Fan motor

Abstract

The invention relates to a fan motor. The fan motor is a reverse fan motor in which the impeller is disposed on the downstream side of the motor with respect to the airflow direction. Thus, the cooling performance of the motor is improved. The fan motor includes a spring that applies a preload to the bearing. Therefore, the gap between the ball of the bearing and the track wheel is removed, and the service life of the bearing can be prolonged. One of the two bearings is disposed close to the impeller. The bearing arranged close to the impeller is a load bearing. The fan motor includes a stopper disposed on an inner side of the motor cover and surrounding one surface of the load bearing. As a result, the stopper can restrict the load bearing from moving in the thrust direction when the load bearing receives thrust during operation.

Description

Technical Field

[0001] The present invention relates to a fan motor that uses an electric motor as a power source to generate airflow. Background Art

[0002] The motor can be installed in household appliances such as vacuum cleaners and hair dryers.

[0003] Vacuum cleaners, hair dryers, etc. may use motors as a power source to generate rotational force.

[0004] Generally, a vacuum cleaner uses the suction power of a fan motor to remove dust, etc. In order to improve cleaning performance such as dust removal and increase capacity, it is necessary to increase the suction power of the fan motor.

[0005] In order to increase the suction force of the fan motor, the fan speed needs to be maintained at a high speed, for example, 10,000 rpm to 140,000 rpm.

[0006] However, when the fan rotates at the rotational speed described above, there is a possibility that the life of the bearing may be adversely affected.

[0007] For example, a ball bearing includes a ball and a raceway wheel surrounding the ball. The raceway wheel includes an inner race located radially inward of the ball across the ball and an outer race located radially outward of the ball.

[0008] The balls roll and rotate at high speed between the inner and outer wheels. If a gap is generated between the balls and the track wheel during operation of the fan motor, vibration and noise are generated due to the gap, thereby shortening the life of the bearing and reducing its durability.

[0009] To improve this problem, when assembling the bearing to the fan motor housing, the gap between the ball and the raceway can be eliminated by applying preload to the outer raceway of the bearing. The outer raceway of the bearing can be fixed to the fan motor housing using adhesive or the like.

[0010] However, even if preload is applied to the bearings, thrust is applied to the impeller, the rotating shaft, the two bearings, and the like as rotating bodies during high-speed operation, causing the following problem.

[0011] Of the two bearings, preload can be applied to the second bearing that is further away from the impeller.

[0012] When the fan motor is running, if the first bearing of the two bearings arranged closer to the impeller is subjected to thrust, the balls and the track wheel of the first bearing are in contact with each other and are loaded by the thrust acting in the same direction as the preload.

[0013] At this time, the outer race of the first bearing needs to be restricted to prevent it from moving in the thrust direction.

[0014] However, during operation, there is a problem that the first bearing is overloaded, which shortens the life of the bearing.

[0015] In addition, if the second bearing of the two bearings is subjected to thrust, the gap between the ball and the track wheel of the second bearing becomes larger under the action of the thrust.

[0016] Therefore, there is a problem that the second bearing may cause abnormal movement such as vibration and slipping of the balls due to the increase in the gap between the balls and the raceway.

[0017] In particular, if the load bearing receiving the thrust is located away from the impeller, a moment is generated around the load bearing when the impeller rotates at high speed, thereby increasing vibration between the rotating shaft and the bearing, which may further shorten the life of the bearing.

[0018] Fan motors can be divided into forward fan motors and reverse fan motors based on the position of the impeller and motor.

[0019] A forward fan motor is a fan motor in which the impeller is located upstream of the motor, based on the direction of air flow.

[0020] A reverse fan motor is a fan motor in which the impeller is located on the downstream side of the motor with respect to the direction of air flow.

[0021] However, in the case of a forward fan motor, the air temperature rises while passing through the impeller, which causes a problem in that the cooling performance of the motor is degraded.

[0022] In the case of a reverse fan motor, air passes through the motor first and then through the impeller, so the motor cooling performance is better than that of a forward fan motor, so it is necessary to research and develop a reverse fan motor.

[0023] In addition, the reverse fan motor requires a completely new structural design based on the bearing preload application method.

[0024] Patent Document 1, which is a prior art related to a bearing preload structure of a reverse fan, namely US Pat. No. 5,904,471A (published on May 18, 1999, hereinafter referred to as Patent Document 1), discloses a cooling method for an electric centrifugal air compressor.

[0025] The spring in Patent Document 1 applies preload to the outer race of one of the two bearings. This causes the outer races of the two bearings to be positioned inward of the inner races of the two bearings, axially approaching each other. This bearing preload method is referred to as an inward preload method.

[0026] However, in Patent Document 1, the axial distance between the center of gravity of the impeller and the outer wheel is greater than the axial distance between the center of gravity of the impeller and the inner wheel.

[0027] Therefore, Patent Document 1 has a problem in that the moment generated by the impeller increases due to the positional relationship between the impeller and the bearing, making it difficult to stably support the bearing and shortening the life of the bearing.

[0028] In addition, if the bearing is subjected to thrust during operation, the gap between the bearing balls and the track wheel will expand, causing the bearing to generate vibration and noise.

[0029] In the prior art patent document 2 related to the bearing preload structure of the reverse fan, namely CN112268009A (publication date: 2021.1.26, hereinafter referred to as patent document 2), a fan and a cleaning appliance product are disclosed.

[0030] However, in the case of Patent Document 2, when rotating at high speed, the distance between the bearing receiving the preload and thrust load and the impeller increases, causing the vibration of the rotating shaft and the like to intensify, and the life of the bearing may be further shortened.

[0031] In the prior art patent document 3 related to the bearing preload structure, namely JP2020-032254A (publication date: 2020.3.5, hereinafter referred to as Patent Document 3), a blower having a bearing tube is disclosed.

[0032] Patent Document 3 includes a forward fan located upstream of the motor relative to the air flow direction and a reverse fan located downstream of the motor. A load bearing is positioned adjacent to the forward fan. A semi-load bearing, which receives preload, is positioned adjacent to the reverse fan.

[0033] According to Patent Document 3, the outside air cools the motor after passing through the forward fan, and the air that has passed through the motor is exhausted to the outside after passing through the reverse fan.

[0034] However, in Patent Document 3, the air temperature rises while passing through the forward fan, so there is a problem that the cooling performance of the motor is lowered compared to the reverse fan motor.

[0035] Furthermore, the spring of Patent Document 3 applies preload to the inner ring of the semi-load bearing.

[0036] However, in Patent Document 3, since the washer arranged between the spring and the inner wheel contacts the inner wheel to transmit preload to the inner wheel as a rotating body, the friction between the inner wheel and the washer causes the inner wheel to wear, thereby causing fatal damage to the bearing.

[0037] Since the inner wheel rotates, torque is applied to the spring, which may cause fatal damage to the spring.

[0038] In particular, Patent Document 3 has a problem in that the preload of the spring causes rotational resistance of the inner wheel, and therefore cannot be applied to a fan motor that needs to rotate at a high speed (100,000 rpm to 140,000 rpm). Summary of the Invention

[0039] Problems to be solved by the invention

[0040] An object of the present invention is to provide a fan motor having a structure that can solve the above-mentioned problems.

[0041] A first object is to provide a fan motor having a structure capable of improving the cooling performance of the motor.

[0042] A second object is to provide a fan motor having a structure capable of extending the life of a bearing and improving durability.

[0043] A third object is to provide a fan motor having a structure that can stably support a bearing against the torque of the fan.

[0044] A fourth object is to provide a fan motor having a structure capable of limiting the movement of a bearing in the thrust direction during high-speed operation.

[0045] A fifth object is to provide a fan motor having a structure capable of maintaining a constant preload magnitude according to a temperature difference between a rotating shaft and a cover and wear of a bearing during operation.

[0046] Technical solutions to the problem

[0047] As a result of in-depth research by the inventors, it was found that the problem of the present invention and the first to fifth purposes mentioned above can be achieved through the following embodiments of the present invention.

[0048] In order to achieve the first purpose mentioned above, the fan motor of the present invention includes: a rotating shaft; an impeller rotatably mounted on the rotating shaft to form an airflow along the axial direction; a motor, arranged on the upstream side of the impeller based on the direction of the airflow, including a rotor coupled to the rotating shaft and a stator surrounding the outer circumference of the rotor, and the motor drives the impeller.

[0049] Thus, since the motor is arranged on the upstream side of the impeller, the external air first cools the motor and then passes through the impeller, thereby improving the cooling performance of the motor.

[0050] The fan motor includes a motor housing for accommodating the motor and a plurality of bearings for supporting the rotating shaft. The plurality of bearings includes a first bearing disposed upstream of the motor and a second bearing disposed downstream of the motor.

[0051] In order to achieve the second object, the fan motor may include a spring for applying preload to the first bearing, thereby extending the life of the bearing and improving its durability.

[0052] To achieve the fourth objective, the fan motor may include a stopper disposed inside the motor housing and surrounding a portion of a surface of the second bearing facing the rotor. The stopper may thereby restrict movement of the second bearing in a thrust direction opposite to the airflow direction.

[0053] In order to achieve the third object, in the fan motor, the second bearing may be arranged adjacent to the impeller, thereby minimizing the moment of the impeller and stably supporting the bearing.

[0054] Alternatively, the second bearing may be arranged on the upstream side or the downstream side of the impeller. Thus, an appropriate bearing preload method may be selected according to the positions of the bearing and the impeller.

[0055] The bearing may be a ball bearing, which may include an inner wheel coupled to the rotating shaft, an outer wheel disposed radially outward of the inner wheel, and balls disposed between the inner wheel and the outer wheel and in rolling contact with the inner wheel and the outer wheel.

[0056] The spring can apply preload to the outer wheel of the first bearing in the direction of the thrust. The axial distance between the outer wheel of the first bearing and the outer wheel of the second bearing can be greater than the axial distance between the inner wheel of the first bearing and the inner wheel of the second bearing. Thus, the spring can apply preload to the bearing in an outward direction.

[0057] The spring can preload the outer wheel of the first bearing toward the airflow direction. The axial distance between the outer wheel of the first bearing and the outer wheel of the second bearing can be smaller than the axial distance between the inner wheel of the first bearing and the inner wheel of the second bearing. Thus, the spring can preload the bearing inward.

[0058] The motor and impeller can be positioned between the first and second bearings. Based on the airflow direction, the bearings can be arranged in the order of first bearing, motor, impeller, and second bearing. In this arrangement, an inward preload method provides more stable bearing support against the impeller's torque than an outward preload method.

[0059] The motor cover may include: a first bearing cover disposed on an upstream side of the motor and accommodating the first bearing; and a second bearing cover disposed on a downstream side of the motor and accommodating the second bearing.

[0060] In order to achieve the fifth purpose mentioned above, the fan motor may further include a retaining member, which is arranged on the inner side of the first bearing cover and supports the spring. The retaining member may include: a spring inner wall portion, which surrounds the inner side of the spring and is combined with the outer peripheral surface of the first bearing; a spring outer wall portion, which surrounds the outer side of the spring and is arranged facing the inner peripheral surface of the first bearing cover; and a connecting portion, which connects one end of the spring inner wall portion and one end of the spring outer wall portion in the direction opposite to the motor. The motor cover may further include a spring support portion, which is arranged toward the motor, protrudes from the inner peripheral surface of the first bearing cover, and supports the end of the spring facing the rotor. Thus, the spring accommodated and supported on the inner side of the retaining member and the spring support portion pulls the first bearing in the direction opposite to the motor, thereby being able to apply pre-stress to the plurality of bearings in an outward manner.

[0061] The retaining member may further include an O-ring mounted on the outer circumferential surface of the spring outer wall portion and movably contacting the inner circumferential surface of the first bearing cover in the thrust direction. Thus, the O-ring can prevent the first bearing from sliding in the circumferential direction. Furthermore, the O-ring allows the retaining member to move axially on the inner circumferential surface of the first bearing cover, thereby allowing the first spring to constantly apply preload (constant preload) to the first bearing in the thrust direction even during operation.

[0062] The motor cover may further include an alignment guide protruding from an inner end of the spring support portion toward the spring inner wall portion and arranged to overlap with the spring inner wall portion in the axial direction. Thus, the alignment guide is aligned with the spring inner wall portion in the axial direction, thereby easily aligning the spring inner wall portion and the first bearing.

[0063] The motor housing may include: a motor support portion that surrounds the outer circumference of the motor and extends axially to support the motor; a first bridge portion that extends radially from the outer circumference of the first bearing housing toward the upstream end of the motor support portion; and a second bridge portion that extends radially from the outer circumference of the second bearing housing toward the downstream end of the motor support portion. Thus, the motor support portion can firmly support the motor.

[0064] The motor support portions may be provided in a plurality and may be spaced apart circumferentially along the outer peripheral edge of the motor. The motor housing may further include an outer ring portion that extends circumferentially and connects the downstream ends of the plurality of motor support portions. Thus, the plurality of motor support portions may be connected and supported by the outer ring portion.

[0065] The stopper may be arranged toward the motor and protrude from the inner peripheral surface of the second bearing cover so that the one surface of the second bearing is locked to the stopper, thereby restricting the second bearing from moving in the thrust direction during high-speed operation of the impeller.

[0066] The diameter of the second bearing may be greater than or equal to the diameter of the first bearing. Thus, the second bearing, as a load bearing close to the impeller, can better withstand thrust during operation.

[0067] The fan motor may further include blades that are arranged on a downstream side of the impeller and guide the airflow.

[0068] The fan motor may further include: an impeller cover coupled to a downstream end portion of the motor cover to accommodate the impeller; and a blade cover coupled to a downstream end portion of the impeller cover to support the blades.

[0069] The upstream end of the impeller cover may be coupled to the inner circumferential surface of the downstream end of the motor cover, and the downstream end of the impeller cover may be coupled to the inner circumferential surface of the upstream end of the blade cover.

[0070] The blades may be composed of single-stage blades or double-stage blades.

[0071] The blade cover supporting the blade may include: a blade outer wall portion, connected to the radial outer end of the blade and combined with the downstream end of the impeller cover; and a blade inner wall portion, connected to the radial inner end of the blade and arranged on the downstream side of the impeller.

[0072] Effects of the Invention

[0073] According to the embodiments of the present invention, the following effects can be achieved.

[0074] First, the impeller is mounted on one end of the rotating shaft, forming a reverse fan motor in which the impeller is arranged downstream of the motor based on the air flow direction, thereby improving the cooling performance of the motor.

[0075] In contrast, Patent Document 3 includes a forward fan located on the upstream side of the motor with reference to the flow direction of air and a reverse fan located on the downstream side of the motor.

[0076] Therefore, in Patent Document 3, the air temperature rises while the air passes through the forward fan, so there is a problem that the cooling performance of the motor is lowered compared to the reverse fan motor.

[0077] Second, when the impeller is arranged on the outside of the two bearings and adjacent to any one of the two bearings, an outward preload method is adopted, that is, preload is applied to the outer wheels of the two bearings in a direction away from each other toward the outsides of the two inner wheels of the bearings. Therefore, even if the torque of the impeller is generated during operation, the bearing can stably support the torque of the impeller.

[0078] In contrast, Patent Document 1 adopts an inward method, that is, preloading is applied to the outer ring of the first bearing arranged on the upstream side based on the air flow direction of the two bearings, so that the outer rings of the two bearings are arranged on the inner sides of the inner rings of the two bearings.

[0079] If the impeller is moving, a moment is generated at the impeller's center of gravity. The magnitude of the impeller's moment varies depending on the axial distance from the outer ring of the bearing. For example, the greater the axial distance between the impeller's center of gravity and the outer ring of the second bearing closest to the impeller, the greater the magnitude of the moment.

[0080] On the contrary, the closer the axial distance between the center of gravity of the impeller and the outer wheel of the second bearing is, the smaller the magnitude of the torque is.

[0081] In the inward preload method of Patent Document 1, the axial distance d1 between the center of gravity of the outer race of the second bearing and the impeller is greater than the axial distance d2 between the center of gravity of the inner race and the impeller. Furthermore, in the inward preload method of Patent Document 1, the axial distance d1 between the center of gravity of the outer race of the second bearing and the impeller is greater than the axial distance d1 between the center of gravity of the outer race of the second bearing and the impeller in the present invention.

[0082] Therefore, the inward preload method of Patent Document 1, compared with the present invention (outward preload method), increases the moment generated by the impeller due to the positional relationship between the impeller and the bearing, making it difficult to stably support the bearing and shortening the bearing life.

[0083] Third, a stopper located inside the motor housing surrounds at least a portion of the motor-facing surface of the outer ring of the second bearing. This stopper restricts movement of the second bearing, which serves as the load-bearing bearing adjacent to the impeller, in the thrust direction. Consequently, even if thrust is generated by the impeller during operation, the second bearing adjacent to the impeller can resist the impeller's thrust, thereby improving the bearing's support performance.

[0084] In contrast, in Patent Document 1, although the second bearing disposed adjacent to the impeller receives thrust during high-speed operation, the second bearing does not have a structure capable of restricting movement in the thrust direction, which is different from the present invention (the same is true for Patent Document 2).

[0085] Therefore, in Patent Documents 1 and 2, if the bearing receives thrust during operation, the gap between the balls of the bearing and the raceway wheel increases, causing a problem in that the bearing generates vibration and noise.

[0086] In Patent Document 3, the load bearing is disposed adjacent to the forward fan, while the semi-load bearing receiving preload is disposed adjacent to the reverse fan.

[0087] However, Patent Document 3 differs from the present invention in that the load spring is disposed away from the reversing fan.

[0088] Therefore, in Patent Document 3, during high-speed rotation, the weight of the impeller intensifies the vibration of the rotating shaft and the like, thereby causing a problem of further shortening the life of the bearings.

[0089] Fourth, the first of the two bearings, located upstream of the motor, is preloaded by a spring and acts as a semi-load bearing. The second bearing, located downstream of the motor, acts as a load bearing subject to thrust. The second bearing's proximity to the impeller minimizes the impeller's torque during operation, thereby maintaining stable bearing support strength.

[0090] In contrast, in Patent Document 2, the half-load bearing that receives the preload of the two bearings is arranged adjacent to the impeller.

[0091] In the case of Patent Document 2, the load bearing receiving the preload and thrust is arranged away from the impeller.

[0092] However, in the case of Patent Document 2, when rotating at high speed, the load bearing and the impeller are spaced apart from each other, and vibration of the rotating shaft and the like is intensified, so that the life of the bearing may be further shortened.

[0093] Fifth, a spring is installed inside the retainer to transmit the spring's preload. The inner wall of the retainer's spring engages the outer circumference of the outer race of the first bearing. Furthermore, an O-ring is attached to the outer wall of the retainer's spring, allowing the retainer to move in the direction of thrust on the inner circumference of the first bearing housing. Therefore, when thrust is generated on the impeller during operation, the spring and retainer move in the direction of thrust, preventing the formation of gaps between the bearing's balls and the raceway. This also reduces bearing vibration and noise, extending bearing life.

[0094] In contrast, the spring of Patent Document 1 applies preload by directly contacting the outer ring of the first bearing. However, the spring of one embodiment of the present invention applies preload indirectly to the bearing via a retaining member, which is different from Patent Document 1 (the preload applying device of Patent Document 2 also directly contacts the bearing).

[0095] Furthermore, in Patent Document 1, the outer races of the two bearings are bonded to the fan motor cover, thereby fixing the axial position between the two bearings (also known as positioning preload), which is different from the present invention.

[0096] In reality, when a fan motor is running, a temperature difference occurs between the rotating shaft and the bearing housing. Furthermore, the preload may vary due to factors such as internal bearing wear.

[0097] When the initially designed preload level changes, the critical speed of the rotating components (such as the shaft, bearings, and rotor) decreases. This reduces the life of the shaft or bearings. Furthermore, Patent Document 3 differs from the present invention in that the outer races of the two bearings are bonded to the inner circumference of the support tube, thereby securing the axial position of the two bearings (also known as a fixed preload).

[0098] Therefore, Patent Document 3 has the same problem as that of Patent Document 1 described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 It is a perspective view showing the appearance of the fan motor of the present invention.

[0100] Figure 2 It will Figure 1 The components of the fan motor are broken down into pieces and shown in an exploded view.

[0101] Figure 3 It is along Figure 1 The cross-sectional view taken along line III-III is a conceptual diagram for explaining the structure of the reverse fan motor.

[0102] Figure 4 It shows Figure 1 Conceptual diagram of the structure of the motor cover. Figure 4 a is a diagram showing the motor cover as viewed from above. Figure 4 b is a diagram showing the motor cover as viewed from below.

[0103] Figure 5 It is magnified Figure 3 The V part in the figure is used to illustrate the concept of the bearing preload structure.

[0104] Figure 6 It is magnified Figure 5 Part VI in FIG. 1 is a conceptual diagram showing a situation in which the first bearing and the retainer are movable in the axial direction along the inner circumferential surface of the first bearing cover using an O-ring.

[0105] Figure 7 It shows Figure 6 A three-dimensional diagram of the structure of the retaining member.

[0106] Figure 8 It is shown in Figure 7 A conceptual diagram showing a spring installed inside a retainer.

[0107] Figure 9 Is used to illustrate Figure 3 Conceptual diagram of the outward preload method for bearings.

[0108] Figure 10 This is a conceptual diagram for explaining the effect of the fan motor of the present invention when it receives thrust during operation.

[0109] Figure 10 a is a conceptual diagram for explaining the operation of the preload applying device for the bearing when the fan motor of the present invention stops operating. Figure 10 b is a conceptual diagram for explaining the action and effect of the preload applying device of the present invention when the fan motor is subjected to thrust during operation.

[0110] Figure 11 This is a conceptual diagram used to compare and illustrate the effects of inward and outward preload methods on bearings in a reverse fan motor. Figure 11 a shows the inward preload method of the bearing. Figure 11 b shows the outward preload method of the bearing.

[0111] Figure 12 Is used to illustrate Figure 3 A conceptual diagram showing a situation in which a first bearing, a rotor, a second bearing, and an impeller are sequentially coupled to the interiors of a motor cover, an impeller cover, and a blade cover.

[0112] Figure 13 FIG. 1 is a conceptual diagram showing a structure of a reverse fan motor according to another embodiment of the present invention.

[0113] Figure 14 This conceptual diagram compares and explains the inward and outward preload methods based on the arrangement relationship between the impeller and two bearings. Figure 14 a shows the inward preloading method. Figure 14 b shows the outward preloading method.

[0114] Figure 15 This is a conceptual diagram showing a fan motor according to still another embodiment of the present invention. DETAILED DESCRIPTION

[0115] Hereinafter, a fan motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0116] In the following description, in order to make the features of the present invention more clear, the description of some structural elements may be omitted.

[0117] 1. Definition of terms

[0118] Terms including ordinal numbers such as "first" and "second" may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from other components.

[0119] When a component is referred to as being “connected” or “linked” to another component, it should be understood that it may be directly connected or linked to the other component, but other components may also be present between them. Conversely, if a component is referred to as being “directly connected” or “directly linked” to another component, it should be understood that no other components exist between them.

[0120] Unless the context clearly indicates otherwise, expressions in the singular used in this specification include expressions in the plural.

[0121] The term "fan motor" used in the following description should be understood as a concept of a device that rotates a fan using power of an electric motor or the like to suck in or blow air.

[0122] The term "radial" or "radial shape" used in the following description refers to a shape extending from a center point to all sides like wheel spokes.

[0123] The term "thrust" used in the following description refers to the force applied to the impeller in the opposite direction to the axial direction when the impeller draws in a fluid such as air in the axial direction. "Thrust" refers to the force acting on the impeller or the rotating shaft to which the impeller is mounted.

[0124] The "axial direction" used in the following description refers to the longitudinal direction of the rotation shaft.

[0125] The "radial direction" used in the following description refers to the length direction of a line segment from the center of a circle or a cylinder to a point on the circumference (circumference).

[0126] The "circumferential direction" used in the following description refers to the direction of the circumferential edge.

[0127] The bearing preload application methods used in the following description can be divided into inward preload method and outward preload method.

[0128] Inward preload refers to applying preload to one of the two bearings, causing the outer races of the two bearings to move axially closer to each other relative to the inner races of the two bearings. In other words, the name "inward preload" comes from the fact that in this method, preload is applied to one of the two bearings, causing the outer races of the two bearings to move inward of the inner races of the two bearings.

[0129] Outward preload refers to applying preload to the bearings so that the outer races of the two bearings move axially away from each other relative to the inner races of the two bearings. In other words, outward preload gets its name from the fact that in this method, preload is applied to one of the two bearings, causing the outer race of the two bearings to move outward of the inner race of the two bearings.

[0130] 2. Description of the structure of the fan motor according to one embodiment of the present invention

[0131] Figure 1 It is a perspective view showing the appearance of the fan motor of the present invention.

[0132] Figure 2 It will Figure 1 The components of the fan motor are broken down into pieces and shown in an exploded view.

[0133] Figure 3 It is along Figure 1 The cross-sectional view taken along line III-III is a conceptual diagram for explaining the structure of the reverse fan motor.

[0134] Figure 4 It shows Figure 1 A conceptual diagram of the structure of the motor cover 110 in FIG. Figure 4 a is a diagram showing the motor cover 110 as viewed from above. Figure 4 b is a diagram showing the motor cover 110 as viewed from below.

[0135] The fan motor of the present invention can be applied to household appliances such as handheld vacuum cleaners.

[0136] The fan motor can be divided into a forward fan motor and a reverse fan motor according to the relative positions of the impeller 140 and the motor 100. In this embodiment, a case where the fan motor is composed of a reverse fan motor is shown.

[0137] The fan motor of the present invention includes a motor housing 110 and a motor 100. The motor housing 110 forms the appearance of the fan motor and houses the motor 100.

[0138] The motor 100 may include a rotating shaft 101 , a rotor 104 , and a stator 106 .

[0139] The rotating shaft 101 is disposed at the center of the motor housing 110 and the impeller housing 143 described later. The rotating shaft 101 may extend along a center line passing through the centers of the motor housing 110 and the impeller housing 143 in the axial direction.

[0140] The plurality of bearings 130 may rotatably support both ends of the rotating shaft 101. The plurality of bearings 130 may include a first bearing 131 and a second bearing 132.

[0141] A first bearing support portion 102 is formed on the upstream side of the rotating shaft 101 . A first bearing 131 is press-fitted into the first bearing support portion 102 . A ball bearing, described below, may be used for the first bearing 131 . The first bearing 131 may be disposed on the upstream side of the rotor 104 .

[0142] A second bearing support portion 103 is formed on the downstream side of the rotating shaft 101 . A second bearing 132 is press-fitted into the second bearing support portion 103 . A ball bearing, described below, may be used for the second bearing 132 . The second bearing 132 may be disposed on the downstream side of the rotor 104 .

[0143] A rotor support portion is formed at the center of the rotating shaft 101. The rotor support portion is disposed between the first bearing support portion 102 and the second bearing support portion 103. The rotor 104 is press-fitted into the rotor support portion.

[0144] The rotor 104 includes permanent magnets 105. The rotor 104 may optionally include a rotor core. The permanent magnets 105 may be coupled to the rotating shaft 101 or to the rotor core. In this embodiment, the rotor core is omitted to achieve miniaturization of the motor 100, and the permanent magnets 105 are coupled to the rotor support.

[0145] The stator 106 surrounds the rotor 104 . The stator 106 may surround the permanent magnet 105 .

[0146] The stator 106 includes a stator core 107 and a stator coil 108. The stator core 107 includes a back yoke, a plurality of teeth, and a plurality of slots. The back yoke may be formed in a cylindrical shape. The back yoke may form the outer peripheral edge portion of the stator core 107.

[0147] The teeth may be formed to protrude radially inward from the inner circumferential surface of the back yoke toward the rotating shaft 101. The plurality of teeth may be arranged circumferentially spaced apart along the circumferential edge of the inner circumferential surface of the back yoke. A groove may be formed between two adjacent teeth in the circumferential direction.

[0148] The slots are formed to penetrate the stator core 107 in the axial direction. The plurality of teeth and the plurality of slots are alternately arranged in the circumferential direction.

[0149] The stator coil 108 may be composed of a plurality of three-phase coils. The stator coil 108 is wound around the teeth. An insulator is provided between the stator coil 108 and the stator core 107 to achieve electrical insulation.

[0150] The plurality of grooves may form an internal flow path for cooling the motor 100. Air may flow through the internal flow path to cool the motor 100.

[0151] A lead wire 109 for applying power extends axially from one side of the stator coil 108. The lead wire 109 can be connected to an external power connection portion 126 to receive external power.

[0152] With this configuration, when a power source such as alternating current is applied to stator coil 108, a magnetic field is generated around stator coil 108. Due to electromagnetic interaction between rotor 104 and stator 106, rotor 104 rotates relative to stator 106. Permanent magnet 105 rotates along with rotating shaft 101, generating a rotational force.

[0153] The motor housing 110 includes a support portion 111 , a first bearing housing 114 , and a second bearing housing 115 .

[0154] The support portion 111 extends in the axial direction. The support portion 111 surrounds a portion of the outer circumference of the stator core 107 to support the stator 106. A plurality of support portions 111 are provided. The plurality of support portions 111 are arranged circumferentially spaced apart along the outer circumference of the stator core 107.

[0155] In this embodiment, three support portions 111 are provided. The number of support portions 111 may be provided in accordance with the number of leads 109. The plurality of support portions 111 may be arranged at intervals of 120 degrees along the circumferential direction.

[0156] A motor housing portion 112 may be recessed on the inner side of the support portion 111. The upstream end of the motor housing portion 112 forms a radial step with the inner side of the support portion 111. The step formed on the upstream end of the motor housing portion 112 contacts the upstream end of the stator core 107 to restrict axial movement of the stator 106.

[0157] First openings 113 are formed radially between circumferentially adjacent support portions 111. First openings 113 connect the exterior and interior of motor housing 110, allowing air outside the fan motor to flow into the internal flow path of motor 100. The plurality of first openings 113 and the plurality of support portions 111 are alternately arranged along the circumference.

[0158] The first bearing cover 114 is disposed on the upstream side of the motor 100. The first bearing cover 114 may be formed in a cylindrical shape. The first bearing cover 114 surrounds the first bearing 131. The first bearing cover 114 accommodates the first bearing 131.

[0159] A plurality of first bridge portions 116 may be disposed between the upstream end of the support portion 111 and the outer peripheral surface of the first bearing housing 114. The first bridge portions 116 connect the upstream end of the support portion 111 and the outer peripheral surface of the first bearing housing 114. The first bridge portions 116 extend radially.

[0160] A plurality of first bridge portions 116 are circumferentially spaced at predetermined intervals along the outer circumference of the first bearing housing 114. Second openings 118 are formed axially between adjacent first bridge portions 116. Second openings 118 connect the exterior and interior of the motor housing 110, allowing air from the fan motor to flow into the internal flow path of the motor 100. The plurality of second openings 118 and the plurality of first bridge portions 116 are alternately arranged circumferentially.

[0161] The radially outer end of the first bridge portion 116 may be connected to the upstream end of the support portion 111. The radially inner end of the first bridge portion 116 may be connected to the outer circumferential surface of the first bearing housing 114. Thus, the support portion 111 can support the first bearing housing 114 by utilizing the connection between the first bridge portion 116 and the first bearing housing 114.

[0162] An outer ring portion 120 may be provided at the downstream end of the support portion 111. The outer ring portion 120 is formed to extend circumferentially along the downstream outer peripheral edge of the stator 106. Thus, the outer ring portion 120 may connect the downstream ends of the plurality of support portions 111.

[0163] The second bearing cover 115 is concentrically disposed at the inner center of the outer ring portion 120. The first bearing cover 114 and the second bearing cover 115 are spaced apart from each other in the axial direction. The first bearing cover 114 and the second bearing cover 115 are concentrically disposed inside the motor housing 110.

[0164] The second bearing cover 115 is formed in a cylindrical shape and accommodates the second bearing 132 .

[0165] The second bearing cover 115 is arranged on the downstream side of the motor 100 . The second bearing 132 is arranged on the downstream side of the motor 100 .

[0166] A plurality of second bridge portions 117 may be disposed between the downstream end of the support portion 111 and the outer circumference of the second bearing housing 115. The second bridge portions 117 connect the downstream end of the support portion 111 and the outer circumference of the second bearing housing 115. The second bridge portions 117 extend radially.

[0167] The plurality of second bridge portions 117 are arranged at predetermined intervals in the circumferential direction along the outer peripheral surface of the second bearing cover 115. A third opening 119 is formed between the plurality of second bridge portions 117 adjacent to each other in the circumferential direction and extending in the axial direction.

[0168] The third opening 119 is a passage connecting the outside and inside of the motor housing 110 to allow air outside the fan motor to flow into the internal flow path of the motor 100. The third openings 119 and the second bridges 117 are alternately arranged along the circumferential direction.

[0169] A portion of the radially outer end portion of the second bridge portion 117 may be connected to the downstream end portion of the support portion 111 . Another portion of the radially outer end portion of the second bridge portion 117 may be connected to the inner circumferential surface of the outer ring portion 120 .

[0170] The radially inner end of the second bridge portion 117 may be connected to the outer circumferential surface of the second bearing housing 115. Thus, the support portion 111 and the outer ring portion 120 may be connected to the second bearing housing 115 via the second bridge portion 117 to support the second bearing housing 115.

[0171] The impeller 140 is disposed on the downstream side of the motor 100 . The impeller 140 may be disposed on the downstream side of the second bearing 132 .

[0172] The impeller 140 includes a hub 141 and a plurality of blades 142. The impeller 140 may be in the form of a diagonal flow fan.

[0173] Hub 141 is formed with an axial inclination to increase its diameter. The diameter of hub 141 gradually increases from the upstream end toward the downstream end, based on the air flow direction. The upstream end of hub 141 faces motor 100.

[0174] An impeller 140 support portion 111 is formed at a downstream end portion of the rotary shaft 101. The second bearing support portion 103 may be disposed between the rotor support portion and the impeller 140 support portion 111.

[0175] A shaft coupling hole is formed in the center of the hub 141 along the axial direction, so that the support portion 111 of the impeller 140 of the rotating shaft 101 can be press-fitted and coupled to the center of the hub 141 .

[0176] Each of the plurality of blades 142 may be formed to extend in a spiral shape along the axial direction of the hub 141. One end of the blade 142 may be formed to protrude radially from the upstream end of the hub 141. The other end of the blade 142 may be formed to protrude from the downstream end of the hub 141 toward the upstream side of the hub 141.

[0177] The plurality of blades 142 are arranged at predetermined intervals along the circumferential direction of the hub 141 .

[0178] Thus, the impeller 140 can rotate together with the rotating shaft 101. The plurality of blades 142 can rotate at high speed together with the hub 141, so that the air passing through the motor 100 flows toward the impeller cover 143 and is sucked in.

[0179] The impeller cover 143 may be disposed at the downstream end of the motor cover 110. The impeller cover 143 and the motor cover 110 are coupled to each other. The upstream end of the impeller cover 143 and the downstream end of the motor cover 110 may be overlapped and coupled to each other.

[0180] For example, the first fastening portion 144 may be formed to protrude radially outward at the upstream end portion of the impeller cover 143. The first fastening portion 144 may extend circumferentially along the periphery of the impeller cover 143.

[0181] A plurality of first fastening holes may be formed axially through the outer ring portion 120. The plurality of first fastening holes may be spaced apart along the circumferential direction of the outer ring portion 120. A plurality of second fastening holes may be formed axially through the first fastening portion 144. The first fastening holes and the second fastening holes may overlap in the axial direction. Fastening members such as bolts may be passed through the first fastening holes and the second fastening holes to be fastened to the outer ring portion 120 and the first fastening portion 144. Thus, the outer ring portion of the motor cover 110 and the first fastening portion 144 of the impeller cover 143 can be fastened together using the fastening members.

[0182] The impeller cover 143 may be formed in a conical shape and together with the motor cover 110 form the appearance of the fan motor.

[0183] The impeller cover 143 may be formed in a shape corresponding to the shape of the hub 141 of the impeller 140 . However, the diameter of the impeller cover 143 is larger than the diameter of the impeller 140 to form a first flow path portion between the impeller cover 143 and the impeller 140 .

[0184] The impeller cover 143 has an accommodation space therein for accommodating the impeller 140. A suction port is formed at the upstream end of the impeller cover 143. The suction port is connected to the downstream end of the motor cover 110 so as to be communicable therewith.

[0185] The impeller cover 143 includes an inclined portion. The inclined portion is formed to be inclined so that the diameter gradually increases from the upstream end of the impeller cover 143 toward the downstream end of the impeller cover 143.

[0186] Blades 146 are arranged on the downstream side of impeller 140. Blades 146 guide the flow of air generated by impeller 140. Blades 146 can guide the rotational flow of impeller 140 in the axial direction. Blades 146 can be composed of single-stage blades 146 or double-stage blades 146. In this embodiment, a configuration with double-stage blades 146 is shown.

[0187] A blade cover 148 is disposed downstream of the impeller cover 143. The upstream end of the blade cover 148 is coupled to the downstream end of the impeller cover 143. The downstream end of the impeller cover 143 and the upstream end of the blade cover 148 may be coupled so as to overlap each other.

[0188] For example, the second fastening portion 145 may be provided at the downstream end portion of the impeller cover 143. The second fastening portion 145 may be formed to protrude radially outward from the downstream end portion of the impeller cover 143.

[0189] The second fastening portion 145 may extend circumferentially along the downstream peripheral edge of the impeller cover 143. A plurality of third fastening holes may be formed axially through the second fastening portion 145. The plurality of third fastening holes may be spaced apart along the circumferential direction of the second fastening portion 145.

[0190] A coupling portion 157 may be provided at the upstream end of the blade cover 148. The coupling portion 157 may extend circumferentially along the upstream peripheral edge of the blade cover 148. A plurality of fourth fastening holes may be formed through the coupling portion 157 in the axial direction.

[0191] The plurality of fourth fastening holes are spaced apart along the circumferential direction of the coupling portion 157. The third and fourth fastening holes are arranged to overlap each other in the axial direction. Fastening members such as bolts pass through the third and fourth fastening holes to couple the second fastening portion 145 and the coupling portion 157.

[0192] Thus, the downstream end portion of the impeller cover 143 and the upstream end portion of the blade cover 148 can be fastened together by the fastening member.

[0193] Blade cover 148 may include an inner wall portion 150, an outer wall portion 155, and blades 146. Inner wall portion 150 is disposed inside blade cover 148. Inner wall portion 150 is formed in a cylindrical shape. Inner wall portion 150 is disposed on the downstream side of impeller 140. Inner wall portion 150 is connected to one side of blade 146, and therefore, inner wall portion 150 may be referred to as blade 146 inner wall portion 150.

[0194] Outer wall portion 155 is formed into a cylindrical shape. Outer wall portion 155 forms the outer appearance of blade cover 148. Outer wall portion 155 is spaced radially outward from inner wall portion 150. Outer wall portion 155 is connected to the other side of blade 146, so outer wall portion 155 can be referred to as blade 146 outer wall portion 155.

[0195] Blades 146 protrude from the outer circumference of inner wall 150 toward the inner circumference of outer wall 155 . Radially inner ends of blades 146 are connected to the outer circumference of inner wall 150 , while radially outer ends of blades 146 are connected to the inner circumference of outer wall 155 .

[0196] The blades 146 may be formed along the outer circumference of the inner wall portion 150 in a spirally inclined manner. The blades 146 may be formed in a curved shape. A plurality of blades 146 may be provided. The plurality of blades 146 may be spaced apart in a circumferential direction along the outer circumference of the inner wall portion 150. A flow path for air flow is formed between the plurality of blades 146.

[0197] The outer wall 155, the plurality of blades 146, and the inner wall 150 may form a second flow path. The second flow path is disposed downstream of the first flow path, and air passing through the first flow path may be discharged to the outside via the second flow path.

[0198] A protrusion is formed at the upstream end portion of the inner wall portion 150 to protrude radially inward. The protrusion is formed to extend in the circumferential direction along the peripheral edge of the inner wall portion 150.

[0199] The second-stage blade 146 may be configured to be separated in the axial direction. The second-stage blade 146 may be configured to include a first blade 147 and a second blade 148. The first blade 147 may be disposed upstream of the second blade 148.

[0200] The inner wall portion 150 may be composed of a first inner wall portion 151 and a second inner wall portion 152 .

[0201] The first inner wall portion 151 may be formed in a cylindrical shape. The second inner wall portion 152 may be formed in a cylindrical shape. The thickness of the first inner wall portion 151 is smaller than that of the second inner wall portion 152. The first inner wall portion 151 is arranged upstream of the second inner wall portion 152. The first inner wall portion 151 and the second inner wall portion 152 may be continuously and integrally connected in the axial direction.

[0202] The inner wall portion 150 may further include a flow path inner wall portion 153. The flow path inner wall portion 153 is formed in a cylindrical shape and surrounds the outer circumference of the inner wall portion 150. The outer circumference of the flow path inner wall portion 153 may form the same circumference as the outer circumference of the second inner wall portion 152.

[0203] A bend 154 is provided at the upstream end of the flow path inner wall portion 153. A first coupling groove is formed at the corner of the upstream end of the first inner wall portion 151. The first coupling groove is formed as a circumferential depression along the outer circumference of the first inner wall portion 151. Thus, the bend 154 can couple with the first coupling groove.

[0204] The outer wall portion 155 may further include a flow path outer wall portion 156. The flow path outer wall portion 156 is formed in a cylindrical shape. A second coupling groove may be formed at the downstream end of the impeller cover 143. The flow path outer wall portion 156 can be coupled to the second coupling groove. The downstream end of the impeller cover 143 surrounds the outer circumference of the flow path outer wall portion 156.

[0205] First blade 147 is formed to project from the outer circumferential surface of flow path inner wall portion 153 toward the inner circumferential surface of flow path outer wall portion 156. First blade 147 is formed to project radially. The radially inner end of first blade 147 is connected to the outer circumferential surface of flow path inner wall portion 153. The radially outer end of first blade 147 is connected to the inner circumferential surface of flow path outer wall portion 156.

[0206] A plurality of first blades 147 are provided between the flow path inner wall portion 153 and the flow path outer wall portion 156. The plurality of first blades 147 are circumferentially spaced apart along the inner circumference of the flow path inner wall portion 153. A flow path for air flow is formed between the plurality of first blades 147.

[0207] Second blades 148 are formed to project from the outer circumferential surface of second inner wall portion 152 toward the inner circumferential surface of outer wall portion 155. Second blades 148 project radially. The radially inner end portions of second blades 148 are connected to the outer circumferential surface of second inner wall portion 152. The radially outer end portions of second blades 148 are connected to the inner circumferential surface of outer wall portion 155.

[0208] Figure 5 It is magnified Figure 3 The V portion in FIG. 1 is a conceptual diagram illustrating the preload structure of the bearing 130 .

[0209] Figure 6 It is magnified Figure 5 Part VI in FIG. 1 is a conceptual diagram showing a state in which the first bearing 131 and the retainer 123 are movable in the axial direction along the inner circumferential surface of the first bearing cover 114 using the O-ring 127 .

[0210] Figure 7 It shows Figure 6 A three-dimensional view of the structure of the retaining member 123.

[0211] Figure 8 It is shown in Figure 7 A conceptual diagram showing a situation in which a spring 138 is installed inside the retainer 123.

[0212] The bearing 130 may be a ball bearing, which may include inner wheels 133a, 133b, outer wheels 135a, 135b, and balls 137a, 137b.

[0213] The inner wheels 133a and 133b can be cylindrical. A hollow hole is formed inside the inner wheels 133a and 133b for the rotation shaft 101 to pass through. The inner circumferences of the inner wheels 133a and 133b are press-fitted onto the rotation shaft 101. First ball-receiving grooves 134a and 134b are formed radially inwardly on the outer circumferences of the inner wheels 133a and 133b. These first ball-receiving grooves 134a and 134b extend circumferentially along the outer circumferences of the inner wheels 133a and 133b.

[0214] Balls 137a and 137b are spherical in shape. Parts of balls 137a and 137b are accommodated in first ball-receiving grooves 134a and 134b, where they roll in contact with the first ball-receiving grooves 134a and 134b of the inner wheels 133a and 133b. A plurality of balls 137a and 137b are provided. These balls 137a and 137b are circumferentially spaced at predetermined intervals along the first ball-receiving grooves 134a and 134b of the inner wheels 133a and 133b.

[0215] The outer wheels 135a and 135b can be cylindrical. Second ball-receiving grooves 136a and 136b are formed radially outwardly on the inner circumferences of the outer wheels 135a and 135b. These second ball-receiving grooves 136a and 136b extend circumferentially along the inner circumferences of the outer wheels 135a and 135b. The outer circumferences of the outer wheels 135a and 135b can be bonded to the inner circumference of the retainer 123, described later, using an adhesive.

[0216] The other portions of the balls 137a and 137b are received in the second ball-receiving grooves 136a and 136b, and roll in contact with the second ball-receiving grooves 136a and 136b of the outer races 135a and 135b. The plurality of balls 137a and 137b are circumferentially arranged at predetermined intervals along the second ball-receiving grooves 136a and 136b of the outer races 135a and 135b.

[0217] The fan motor of the present invention includes a bearing preload applying device. The bearing preload applying device includes a spring 138. Spring 138 can be a coil spring 138. Spring 138 can extend in a spiral direction. Spring 138 can extend along its length with a constant diameter. A through hole can be formed inside spring 138 to allow the spring inner wall portion 124, described later, to pass through.

[0218] The spring 138 can apply preload to the bearing 130 using the retainer 123 .

[0219] The retainer 123 may include a spring inner wall portion 124, a spring outer wall portion 125, and a connecting portion 126. The spring inner wall portion 124 is formed in a cylindrical shape. A hollow portion is formed inside the spring inner wall portion 124 to surround the outer wheel 135a of the first bearing 131.

[0220] The inner circumference of the spring inner wall portion 124 can be fixed to the outer circumference of the outer ring 135a of the first bearing 131 using an adhesive. An adhesive layer can be formed between the inner circumference of the spring inner wall portion 124 and the outer circumference of the outer ring 135a of the first bearing 131.

[0221] The outer peripheral surface of the spring inner wall portion 124 surrounds the inner peripheral surface of the spring 138 .

[0222] The spring outer wall portion 125 is formed in a cylindrical shape. The diameter of the spring outer wall portion 125 is larger than the diameter of the spring inner wall portion 124. The spring outer wall portion 125 is spaced radially outward from the outer peripheral surface of the spring inner wall portion 124.

[0223] An accommodation space for accommodating the spring 138 is formed between the spring outer wall portion 125 and the spring inner wall portion 124 .

[0224] The inner peripheral surface of the spring outer wall portion 125 surrounds the outer peripheral surface of the spring 138. The outer peripheral surface of the spring outer wall portion 125 is arranged to face the inner peripheral surface of the first bearing cover 114.

[0225] A connection portion 126 is provided between the upstream end of the spring outer wall portion 125 and the upstream end of the spring inner wall portion 124 . The connection portion 126 is formed to project from the upstream end of the spring inner wall portion 124 toward the upstream end of the spring outer wall portion 125 .

[0226] The connecting portion 126 is formed to extend in the circumferential direction along the outer peripheral surface of the spring inner wall portion 124. The connecting portion 126 can connect the upstream end portion of the spring inner wall portion 124 and the upstream end portion of the spring outer wall portion 125.

[0227] The spring 138 accommodation space between the spring inner wall portion 124 and the spring outer wall portion 125 is open toward the rotor 104. The spring 138 accommodation space between the spring inner wall portion 124 and the spring outer wall portion 125 is shielded by the connecting portion 126 in the opposite direction to the rotor 104.

[0228] A portion of the spring 138 may be accommodated in the spring 138 accommodation space between the spring inner wall portion 124 and the spring outer wall portion 125. Another portion of the spring 138 may be accommodated in the inner side surface of the spring support portion 121 of the first bearing cover 114 described later.

[0229] The upstream end of the spring 138 contacts the inner surface of the connecting portion 126. The downstream end of the spring 138 contacts the inner surface of the spring support portion 121 of the first bearing cover 114, which will be described later. The downstream end of the spring 138 is supported by the spring support portion 121.

[0230] Thus, the upstream end portion of the spring 138 can preload the connection portion 126 toward the opposite side of the rotor 104 due to the elastic restoring force.

[0231] With the connection portion 126 as a reference, the length of the spring outer wall portion 125 may extend further in the axial direction toward the rotor 104 than the length of the spring inner wall portion 124 .

[0232] A space for accommodating the first bearing 131 is formed inside the first bearing housing 114. A retainer mounting portion 1141 is formed on the inner circumference of the first bearing housing 114 and is recessed radially inward. The retainer mounting portion 1141 extends circumferentially along the inner circumference of the first bearing housing 114.

[0233] The spring outer wall portion 125 of the retainer 123 may be accommodated in and mounted on the retainer mounting portion 1141 .

[0234] The retainer 123 may further include an O-ring 127. The O-ring 127 may be disposed between the outer circumference of the spring outer wall portion 125 and the inner circumference of the first bearing housing 114. An O-ring mounting groove may be formed in the outer circumference of the spring outer wall portion 125, recessed radially inward.

[0235] An O-ring mounting groove extends circumferentially along the outer circumference of the spring outer wall portion 125 to accommodate an O-ring 127. The O-ring mounting groove may have a quadrilateral cross-sectional shape. The O-ring mounting groove may be sized to correspond to the inner diameter of the O-ring 127 so that the O-ring 127 is inscribed therein and engages with the O-ring mounting groove in an interference fit.

[0236] The O-ring 127 may be formed in a circular ring shape. The outer diameter of the O-ring 127 is formed to a size corresponding to the inner diameter of the holder mounting portion 1141. The outer circumferential surface of the O-ring 127 is in close contact with the inner circumferential surface of the holder mounting portion 1141.

[0237] The downstream end portion of the spring outer wall portion 125 of the retainer 123 can be locked and mounted on the downstream end portion of the retainer mounting portion 1141 .

[0238] The O-ring 127 can be formed of an elastic rubber material. Thus, the O-ring 127 can allow the retainer 123 to move in the thrust direction on the retainer mounting portion 1141. Here, the thrust direction is a direction opposite to the flow direction of the air.

[0239] The thrust direction makes the retainer 123 move toward the upstream side of the retainer mounting portion 1141. Figure 5 As a reference, the thrust direction refers to the upper side of the first bearing 131 .

[0240] In addition, the O-ring 127 can prevent the retainer 123 from sliding in the circumferential direction along the inner circumferential surface of the first bearing cover 114 .

[0241] A spring support portion 121 is provided on the inner circumferential surface of the first bearing cover 114. The spring support portion 121 is formed to protrude radially inward from the inner circumferential surface of the first bearing cover 114. The spring support portion 121 is disposed at the downstream end portion of the inner circumferential surface of the first bearing cover.

[0242] The spring support portion 121 is formed to extend circumferentially along the inner circumferential surface of the first bearing housing 114. The spring support portion 121 provides a spring 138 accommodation space for accommodating the other portion of the spring 138. The downstream end of the spring 138 can be fixedly supported on the inner side surface of the spring support portion 121.

[0243] The first bearing housing 114 may further include an alignment guide 122. The alignment guide 122 may be cylindrical. The alignment guide 122 may protrude axially from the radially inner end of the spring support portion 121 toward the spring outer wall portion 125. A shaft through-hole is formed inside the alignment guide 122 for the rotation shaft 101 to pass through.

[0244] The center of the alignment guide 122 can be arranged concentrically with the center of the rotating shaft 101. The alignment guide 122 surrounds the outer peripheral surface of the first bearing 131. The alignment guide 122 is arranged downstream of the spring outer wall portion 125. The alignment guide 122 and the spring outer wall portion 125 are arranged to overlap in the axial direction.

[0245] The alignment guide 122 and the inner circumferential surface of the spring outer wall portion 125 may form the same circumferential surface in the axial direction. Thus, the alignment guide 122 may guide the alignment of the first bearing 131 . The alignment guide 122 may improve the concentricity of the bearing 130 .

[0246] A bearing 130 accommodation space for accommodating the second bearing 132 is formed inside the second bearing cover 115. The diameter of the inner circumference of the second bearing cover 115 is formed to correspond to the diameter of the outer circumference of the second bearing 132.

[0247] The inner circumferential surface of the second bearing cover 115 and the outer circumferential surface of the second bearing 132 may be bonded together using an adhesive. An adhesive layer may be formed between the inner circumferential surface of the second bearing cover 115 and the outer circumferential surface of the second bearing 132.

[0248] A stopper 139 is provided on the inner circumferential surface of the second bearing housing 115. The stopper 139 is formed to protrude radially inward from the inner circumferential surface of the second bearing housing 115. The stopper 139 is formed to extend circumferentially along the inner circumferential surface of the second bearing housing 115.

[0249] The stopper 139 is disposed facing one surface of the upstream end of the outer race 135b of the second bearing 132. The stopper 139 is disposed so as to surround at least a portion of the axial surface of the outer race 135b of the second bearing 132 that faces the rotor 104. The stopper 139 and the axial surface of the outer race 135b of the second bearing 132 can be disposed in close contact with each other.

[0250] Thus, the stopper 139 can restrict the second bearing 132 from moving in the thrust direction.

[0251] Hereinafter, the operation and effects based on the configuration of the present invention will be described.

[0252] According to the above configuration of the present invention, impeller 140 can be rotated at high speed by receiving power from motor 100 via rotating shaft 101. As impeller 140 rotates, air outside motor housing 110 is drawn into the internal flow path of motor housing 110 through the opening of motor housing 110.

[0253] The motor housing 110 has a first opening 113 formed axially through a plurality of first bridge portions 116 disposed on the upstream side of the motor housing 110. The motor housing 110 has a second opening 118 formed radially through a plurality of support portions 111 that support the outer circumference of the stator 106 housed within the motor housing 110. Air outside the motor housing 110 can be drawn into the motor housing 110 through at least one of the plurality of first openings 113 and the plurality of second openings 118.

[0254] Air drawn into the motor housing 110 comes into contact with the stator core 107, stator coil 108, rotating shaft 101, and bearing 130 of the motor 100, thereby cooling the motor 100. Air passing through the internal flow path of the motor 100 can flow toward the intake port of the impeller cover 143 through the third opening 119 of the motor housing 110. The third opening 119 of the motor housing 110 is formed axially through the plurality of second bridge portions 117 disposed on the downstream side of the motor housing 110.

[0255] Air drawn into the intake port of impeller cover 143 swirls while passing through the first flow path portion between impeller 140 and impeller cover 143. Air that has passed through impeller 140 passes through the second flow path portion of blade cover 148. Air that has passed through impeller 140 is axially guided as it passes through a plurality of first blades 147 and second blades 148 formed between flow path inner wall portion 153 and flow path outer wall portion 156.

[0256] The air that has passed through the blade cover 148 is discharged from the outlet end of the second blade 148 to the outside of the blade cover 148 .

[0257] In the reverse fan motor, the motor 100 is arranged upstream of the impeller 140 based on the air flow direction. Therefore, the external air of the fan motor first passes through the motor 100 while cooling the motor 100, and then passes through the impeller 140 and is discharged outside the fan motor.

[0258] Therefore, the low-temperature external air cools the motor 100 before being sucked into the impeller 140 , thereby improving the cooling performance of the motor 100 .

[0259] The preloading method of the bearing 130 of the present invention will be described.

[0260] Figure 9 Is used to illustrate Figure 3 A conceptual diagram of the outward preload method of the bearing 130 in FIG.

[0261] Before the fan motor is operated, preload is applied to the bearing 130 when the fan motor is assembled.

[0262] The first bearing 131 is preloaded in the thrust direction. Figure 12 , which is a reference, refers to the upper side of the first bearing 131. Preload is applied to the outer race 135a of the first bearing 131.

[0263] Spring 138 applies preload to retainer 123, rather than directly applying preload to first bearing 131. The upstream side of spring 138 is disposed in the spring 138 accommodation space between spring inner wall portion 124 and spring outer wall portion 125. The downstream side of spring 138 is disposed in the spring 138 accommodation space between the inner circumferential surface of first bearing cover 114 and alignment guide 122.

[0264] The upstream end of spring 138 abuts against the inner side surface of connecting portion 126 connecting spring inner wall portion 124 and spring outer wall portion 125. The downstream end of spring 138 abuts against spring 138 support portion 111 connected to the downstream end of the inner circumferential surface of first bearing cover 114 and the downstream end of alignment guide 122.

[0265] The connection portion 126 of the retainer 123 is pressed toward the motor 100, compressing the spring 138 by a predetermined amount. The preload of the spring 138 can be determined based on the amount of compression of the spring 138. The greater the compression of the spring 138, the greater the preload of the spring 138. The initial preload setting value of the spring 138 can vary depending on the capacity and size of the motor 100.

[0266] The elastic restoring force of the spring 138 presses the connecting portion 126 of the retaining member 123 in the thrust direction. The inner peripheral surface of the spring inner wall portion 124 of the retaining member 123 and the outer peripheral surface of the first bearing 131 are bonded to each other. If the connecting portion 126 of the retaining member 123 is pulled in the thrust direction by the elastic restoring force of the spring 138, the outer ring 135a of the first bearing 131 is pulled in the thrust direction together with the retaining member 123. Figure 9 As a reference, the thrust direction is from the bottom to the top of the first bearing 131 .

[0267] The downstream side of the first ball receiving groove 134b of the outer race 135a of the first bearing 131 moves in the thrust direction and comes into close contact with one side position of the balls 137a and 137b.

[0268] The ball 137a is pressed by the outer race 135a of the first bearing 131 moving in the thrust direction. The other side of the ball 137a moves toward the upstream side of the first ball receiving groove 134a of the inner race 133a of the first bearing 131 and adheres to it.

[0269] An imaginary straight line connecting a first position P1 where one side of the ball 137a contacts the outer race 135a of the first bearing 131 and a second position P2 where the other side of the ball 137a contacts the inner race 133a of the first bearing 131 is inclined at a preset angle θ relative to the axial direction.

[0270] The inner race 133a of the first bearing 131 moves in the thrust direction together with the upstream movement of the ball 137a. The rotating shaft 101 moves in the thrust direction together with the inner race 133a of the first bearing 131.

[0271] The inner ring 133 b of the second bearing 132 moves in the thrust direction together with the rotating shaft 101 .

[0272] The downstream side of the first ball receiving groove 134 a of the inner race 133 b of the second bearing 132 moves toward the thrust direction of the second bearing 132 and is in close contact with one side position of the ball 137 b of the second bearing 132 .

[0273] The ball 137b of the second bearing 132 is pressed by the movement of the inner race 133a of the first bearing 131 in the thrust direction. The other side of the ball 137b of the second bearing 132 moves toward the upstream side of the second ball receiving groove 136b of the outer race 135b of the second bearing 132 and comes into close contact with the upstream side of the second ball receiving groove 136b.

[0274] An imaginary straight line connecting a first position P1 where one side position of the ball 137b of the second bearing 132 is connected to the inner wheel 133b of the second bearing 132 and a second position P2 where the other side position of the ball 137b of the second bearing 132 is connected to the outer wheel 135b of the second bearing 132 is inclined at a preset angle θ relative to the axial direction.

[0275] According to this structure, the outer wheel 135a of the first bearing 131 moves toward the upstream side of the inner wheel 133 relative to the inner wheel 133a of the first bearing 131, and the outer wheel 135b of the second bearing 132 moves toward the downstream side of the inner wheel 133 relative to the inner wheel 133b of the second bearing 132.

[0276] As a result, the outer race 135a of the first bearing 131 and the outer race 135b of the second bearing 132 can move axially away from each other. In this preloading method for bearing 130, the outer race 135 of bearing 130 is located outside the inner race 133 of bearing 130, so this preloading method can be called an outward preloading method.

[0277] Therefore, according to the outward preloading method of the bearing 130, as the gap between the track wheel and the ball 137b of the bearing 130 is eliminated, the vibration of the bearing 130 is minimized, thereby extending the life of the bearing 130 even at high speed operation.

[0278] Figure 10 This is a conceptual diagram for explaining the effect of the fan motor of the present invention when it receives thrust during operation.

[0279] Figure 10 a is a conceptual diagram for explaining the operation of the preload applying device for the bearing 130 when the fan motor of the present invention stops operating. Figure 10 b is a conceptual diagram for explaining the action and effect of the preload applying device of the present invention when the fan motor is subjected to thrust during operation.

[0280] Before the fan motor starts operating or stops operating, since the impeller 140 does not rotate, no thrust is generated on the impeller 140 .

[0281] In this case, the initial setting value of the preload amount of the bearing 130 can be maintained.

[0282] When the fan motor is in operation, the impeller 140 rotates, thereby generating thrust on the impeller 140 .

[0283] Because first bearing 131 is preloaded by spring 138 and can move in the thrust direction, it is virtually unaffected by the thrust. Therefore, there is no need to restrict the movement of first bearing 131 in the thrust direction. Because first bearing 131 is not subject to load caused by the thrust, it can be called a semi-load bearing.

[0284] On the other hand, if the second bearing 132 is subjected to thrust during operation, it is affected by the thrust. Since the second bearing 132 is subjected to the load caused by the thrust, it can be named a load bearing.

[0285] If the outer ring 135b of the second bearing 132 is not restricted from moving in the thrust direction, the gap between the balls 137a, 137b and the raceway wheel will increase after preload is applied to the bearing 130, thereby adversely affecting the vibration and life of the bearing 130.

[0286] Therefore, it is necessary to restrict the outer ring 135b of the second bearing 132 from moving in the thrust direction. The stopper 139 of the present invention surrounds at least a portion of the surface of the second bearing 132 facing the rotor 104, thereby restricting the outer ring 135b of the second bearing 132 from moving in the thrust direction.

[0287] Furthermore, the load bearing (second bearing 132 ) of the present invention is arranged adjacent to the impeller 140 .

[0288] If the bearing 132 arranged adjacent to the impeller 140 is a semi-loaded bearing rather than a loaded bearing, the moment generated on the center of gravity of the impeller 140 will change due to changes in the axial distance between the outer ring 135 of the semi-loaded bearing and the center of gravity of the impeller 140 caused by changes in the rotational speed and thrust of the impeller 140 during operation. As a result, the vibration changes of the bearing 130 will be aggravated, resulting in a problem of shortened service life.

[0289] Preferably, the bearing 132 disposed adjacent to the impeller 140 is a load bearing. In addition, it is necessary to restrict the outer ring 135 of the load bearing from moving in the thrust direction.

[0290] Figure 11 This is a conceptual diagram used to compare and illustrate the effects of inward and outward preload methods on bearings in a reverse fan motor.

[0291] Figure 11 Graph a shows the magnitude of the torque generated by the rotation of the impeller 10 when the reverse fan motor adopts the inward preload method, with the thick solid line indicating the magnitude of the torque generated by the rotation of the impeller 10 .

[0292] Figure 11 b shows the situation where the magnitude of the torque generated by the rotation of the impeller 140 is represented by a thick solid line when the reverse fan motor adopts the outward pre-load method.

[0293] exist Figure 11 In FIG. 1 , with the center line OO′ of the rotation shaft 13 , 101 as a reference, the magnitudes of the moments M1 , M2 of the impeller 10 , 140 increase as they approach the X-axis direction (left side).

[0294] The moment is a force that causes rotation around a certain point. When the impeller 10 or 140 rotates, a centrifugal force is generated in the impeller 10 or 140. The centrifugal force of the impeller 10 or 140 is directed radially outward from the center of the rotating shaft 101.

[0295] The impeller 10, 140 has a moment that causes it to rotate about the one bearing 12 closest to the impeller 10, 140. The magnitude of the moment M1, M2 acting on the center of gravity of the impeller 10, 140 varies depending on the axial distance between the bearing 11, 12, 130 as the center point and the center of gravity of the impeller 10, 140.

[0296] Assuming the rotational speed and centrifugal force of impellers 10 and 140 are constant, the greater the axial distance between the center of gravity of impeller 140 and bearing 12, the greater the moments M1 and M2. Moments M1 and M2 are proportional to (the force causing rotation) times (the distance between the center point and the rotating object). Here, the force causing rotation is assumed to be a constant centrifugal force. The center point represents the location of bearing 12. The rotating object represents impellers 10 and 140.

[0297] Reference Figure 11 a. When the impeller 10 is located on the outside of one of the two bearings 11 and 12, according to the inward preload method, the axial distance d1 between the outer wheel of the one bearing 12 (the second bearing 132 of the present invention) and the center of gravity of the impeller 10 is greater than the axial distance d2 between the inner wheel of the one bearing 12 and the center of gravity of the impeller 10.

[0298] Therefore, when the impeller 10 is located outside one of the two bearings 11 and 12 , the moment M1 of the impeller 10 trying to rotate about the outer ring of the one bearing 12 is larger than that of the outward preload method of the present invention described below.

[0299] In particular, when the impeller 10 rotates at a high speed of 100,000 rpm to 140,000 rpm, the magnitude difference of the moment M1 of the impeller 140 becomes larger.

[0300] On the contrary, refer to Figure 11 b. When the impeller 140 is located on the outside of a second bearing 132 of the two bearings 130, according to the outward preload method, the axial distance d1 between the outer wheel 135b of the second bearing 132 and the center of gravity of the impeller 140 is smaller than the axial distance d2 between the inner wheel of the bearing 132 and the center of gravity of the impeller 140.

[0301] In this case, when impeller 140 is located outside one of the two bearings 130, as in the present invention, the moment M2 of impeller 140 attempting to rotate about outer ring 135b of the one bearing 132 is smaller than that of the aforementioned inward preload method. This means that the difference between moments M1 and M2 is even greater when impeller 140 rotates at high speeds.

[0302] Therefore, the impeller 140 of one embodiment of the present invention is located on the outside of the second bearing 132 of the two bearings 130, and the spring 138 applies preload to the first bearing 131 in an outward preload manner, thereby reducing the moments M1 and M2 of the impeller 140 and improving the stable support and support performance of the bearing 130.

[0303] Figure 12 Is used to illustrate Figure 3 1 , a conceptual diagram showing a state in which the first bearing 131 , the rotor 104 , the second bearing 132 , and the impeller 140 are sequentially coupled to the interiors of the motor housing 110 , the impeller housing 143 , and the blade housing 148 .

[0304] The motor 100 is housed and supported within the motor housing 110. A retainer 123 is mounted inside the first bearing housing 114, which is located upstream of the motor housing 110. A spring 138 is mounted in a spring 138 accommodation space formed inside the spring inner wall 124, spring outer wall 125, and connecting portion 126 of the retainer 123.

[0305] The rotor 104 is press-fitted to the center of the rotating shaft 101. The first bearing 131 is disposed upstream of the rotor 104 with respect to the air flow direction. The first bearing 131 is press-fitted to the upstream end of the rotating shaft 101.

[0306] The second bearing 132 is disposed on the downstream side of the rotor 104. The second bearing 132 is press-fitted and coupled to the downstream side of the rotating shaft 101.

[0307] The impeller 140 is disposed on the downstream side of the rotor 104. The impeller 140 may be disposed on the downstream side of the second bearing 132. The impeller 140 is press-fitted to the downstream end portion of the rotating shaft 101.

[0308] The rotor 104 assembly including the first bearing 131 , the rotor 104 , the second bearing 132 , and the impeller 140 may be coupled to the rotating shaft 101 in sequence from the upstream side to the downstream side based on the air flow direction.

[0309] The first bearing 131, the rotor 104, the second bearing 132 and the impeller 140 are respectively accommodated and combined on the inner side of the retaining member 123 of the first bearing cover 114 of the motor cover 110, the inner side of the rotor 104 accommodating portion of the stator core 107, the inner side of the second bearing cover 115 and the inner side of the impeller cover 143.

[0310] Preferably, the diameter of the first bearing 131, that is, the diameter of the outer peripheral surface of the outer ring 135, is smaller than the inner diameter of the rotor 104 accommodating portion of the stator core 107. This facilitates assembly of the bearing 130 and the bearing cover.

[0311] If the diameter of the first bearing 131 is greater than or equal to the inner diameter of the housing of the rotor 104 , the first bearing 131 needs to be pre-assembled to the first bearing housing 114 before the motor 100 is assembled to the support portion 111 of the motor housing 110 .

[0312] For example, the motor 100 may be assembled after the first bearing 131 is pre-assembled. In this case, the first bearing 131 may be press-fitted to the upstream end of the rotating shaft 101 while the first bearing 131 is pre-assembled to the first bearing cover 114 .

[0313] Therefore, there is a problem in that it is difficult to press-fit the first bearing 131 into the rotating shaft 101 .

[0314] Therefore, preferably, the diameter of the second bearing 132 is larger than the diameter of the first bearing 131 .

[0315] Thus, the diameter of the second bearing 132 is larger than the diameter of the first bearing 131 , thereby increasing the support strength of the bearing 130 .

[0316] Since the impeller 140 is arranged outside the second bearing 132 of the two bearings 13 , a torque caused by the rotation of the impeller 140 is generated during operation. Therefore, increasing the strength of the second bearing 132 can effectively increase the force, ie, stress, that attempts to resist the torque of the impeller 140 .

[0317] Figure 13 FIG. 1 is a conceptual diagram showing a structure of a reverse fan motor according to another embodiment of the present invention.

[0318] Figure 14 This is a conceptual diagram for comparing and explaining the inward preload method and the outward preload method based on the arrangement relationship between the impeller 240 and the two bearings 130 . Figure 14 a shows the inward preloading method. Figure 14 b shows the outward preloading method.

[0319] This embodiment is different from the above Figures 1 to 12 The embodiment of the present invention is different in that the impeller 240 is disposed between two bearings 130 and applies preload to the bearings 130 in an inward preload manner.

[0320] Other components are the same as above Figures 1 to 12 The embodiments are the same or similar, so repeated description is omitted.

[0321] The following is similar to the above Figures 1 to 12 The following description will focus on the differences between the embodiments.

[0322] The bearings 130 of this embodiment are preloaded inwards. As described above, preloading inwards means applying preload to the bearings 130 so that the outer races 135 of the two bearings 130 move toward each other and are positioned inwards of the inner races 133 of the two bearings 130.

[0323] The spring 138 positioned between the spring inner wall portion 224 and the spring outer wall portion 225 of the holder 223 applies preload so that the outer race 135 a of the first bearing 131 projects toward the motor 100 relative to the inner race 133 a of the first bearing 131 .

[0324] For this purpose, the spring support portion 221 radially protruding from the inner circumference of the first bearing cover 214 is located at the upstream end of the first bearing cover 214. Here, the upstream end of the first bearing cover 214 refers to the Figure 15The upper end of the first bearing cover 214 is used as a reference.

[0325] The connection portion 226 connecting the spring inner wall portion 224 and the spring outer wall portion 225 of the retainer 223 is located at the downstream side end portion of the retainer 223. Here, the downstream side end portion of the retainer 223 refers to the portion where the spring inner wall portion 224 and the spring outer wall portion 225 are connected. Figure 14 The lower end of the retaining member 223 is used as the reference.

[0326] According to such a configuration, the elastic restoring force of the spring 138 supported by the spring support portion 221 presses the connection portion 226 of the holder 223 toward the rotor 104 in the air flow direction.

[0327] Under the action of the elastic restoring force of the spring 138, the outer wheel 135a of the first bearing 131 protrudes toward the motor 100 relative to the inner wheel 133a of the first bearing 131, and the upstream side of the second ball receiving groove 136a of the outer wheel 135a of the first bearing 131 is in close contact with one side of the ball 137a.

[0328] Then, the other side position in the diagonal direction of the ball 137a is in close contact with the downstream side of the second ball receiving groove 136a of the inner wheel 133a of the first bearing 131 and moves downward, and the inner wheel 133b of the second bearing 132 moves toward the motor 100.

[0329] Afterwards, the rotating shaft 101 pressed into the inner wheel 133a coupled to the first bearing 131 descends toward the second bearing 132 along the air flow direction, and the inner wheel 133b of the second bearing 132 pressed into the rotating shaft 101 moves in the same direction together with the inner wheel 133a of the first bearing 131.

[0330] The upstream side of the second ball receiving groove 136 b of the inner race 133 b of the second bearing 132 is in close contact with one side of the ball 137 b and is lowered.

[0331] The outer ring 135 b of the second bearing 132 is fixed to the inner circumferential surface of the second bearing cover 115 .

[0332] In this way, preload is applied to the bearing 130. The preload method of the above embodiment is an inward preload method.

[0333] In this embodiment, the impeller 240 is disposed on the downstream side of the rotor 104 to form a reverse fan motor. The impeller 240 and the rotor 104 are disposed between the two bearings 130. The impeller 240 is disposed adjacent to the second bearing 132 of the two bearings 130.

[0334] Reference Figure 14a. In the case of the inward preload mode of this embodiment, the axial distance d1 between the center of gravity of the impeller 240 and the outer wheel 135b of the second bearing 132 is smaller than the axial distance d2 between the center of gravity of the impeller 240 and the inner wheel 133b of the second bearing 132.

[0335] Reference Figure 14 b. In the case of outward preload, the axial distance D1 between the center of gravity of the impeller 240 and the outer wheel 135b of the second bearing 132 is greater than the axial distance D2 between the center of gravity of the impeller 240 and the inner wheel 133b of the second bearing 132.

[0336] contrast Figure 14 a and Figure 14 b, assuming that the rotational force of the impeller 240 remains constant, Figure 14 The axial distance d1 between the center of gravity of the impeller 240 of the inward preload method of this embodiment and the outer ring 135 of the second bearing 132 is less than Figure 14 b is the axial distance D1 between the center of gravity of the impeller 240 in the outward preload mode and the outer ring 135 of the second bearing 132.

[0337] Therefore, according to this embodiment, when the impeller 240 is disposed between the two bearings 130 and the bearings 130 are preloaded inwardly, the magnitude of the moment M1 caused by the rotation of the impeller 240 during operation is smaller than the magnitude of the moment M2 of the impeller applied to the bearings in which the preload is applied outwardly. Figure 14 The inward preloading method of the bearing in a) can not only improve the supporting performance of the bearing 130 but also extend the life of the bearing 130 by minimizing the increase in torque.

[0338] According to the above Figures 1 to 14 In the embodiment, even if the preload of the bearing 130 changes during operation due to the temperature difference between the fan motor cover (including the bearing 130 cover) and the bearing 130 and the wear of the bearing 130, the spring 138 of the present invention can also apply a constant preload to the bearing 130.

[0339] For the reasons described above, even if the preload of bearing 130 changes during operation, spring 138 of this embodiment still applies a constant preload to bearing 130, thus being referred to as a constant preload. This constant preload method of the present invention can be achieved using retainer 223 and O-ring 227.

[0340] The O-ring 227 is disposed between the inner peripheral surface of the first bearing cover 214 of the retainer 223 and the spring outer wall portion 225 , and allows the retainer 223 to move in the thrust direction along the inner peripheral surface of the first bearing cover 214 .

[0341] The O-ring 227 is made of elastic material. Therefore, when thrust is generated on the impeller 240 , the retainer 223 can move in the thrust direction, thereby eliminating the gap between the balls 137 a and 137 b and the track wheel.

[0342] Figure 15 This is a conceptual diagram showing a fan motor according to still another embodiment of the present invention.

[0343] This embodiment is different from the above Figures 1 to 12 The difference between the embodiment of the present invention and the embodiment of the present invention is that the impeller 240 is arranged between the two bearings 130 and the bearings 130 are preloaded inwardly. Figure 13 and Figure 14 The embodiment of a is the same or similar in that the impeller 240 is disposed between two bearings 130 and applies preload to the bearings 130 in an inward preload manner.

[0344] Since the other components are the same as above Figures 1 to 14 The embodiment is the same or similar to Figures 1 to 14 The following description will focus on the differences between the embodiments.

[0345] The first bearing 131 , which is disposed on the upstream side with respect to the air flow direction, is fitted on the upstream side of the motor.

[0346] When impeller 240 rotates, thrust is generated on impeller 240, rotating shaft 101, and bearing 130. First bearing 131 is housed in first bearing housing 314. The outer circumference of first bearing 131 can be bonded to the inner circumference of the housing 314 using an O-ring or adhesive. In this embodiment, the outer circumference of first bearing 131 is bonded to the inner circumference of the housing 314 using an adhesive.

[0347] The stopper 339 is formed to protrude radially inward from the upstream end portion of the first bearing cover 314 . The upstream end portion of the first bearing 131 is closely attached to the inner surface of the stopper 339 .

[0348] Thus, the stopper 339 can restrict the first bearing 131 from moving in the thrust direction. The first bearing 131 is a load bearing 130 because it bears the thrust load.

[0349] The impeller 240 is arranged on the downstream side of the motor. The impeller 240 is arranged on the upstream side of the second bearing 132. The second bearing 132 is arranged adjacent to the downstream side of the impeller 240.

[0350] The second bearing 132 is housed inside the second bearing housing 315. The outer circumferential surface of the second bearing 132 can be bonded to the inner circumferential surface of the second bearing housing 315 using an O-ring or adhesive. In this embodiment, the outer circumferential surface of the second bearing 132 is bonded to the inner circumferential surface of the second bearing housing 315 using an adhesive.

[0351] A bearing preload applying device may be housed on the inner side of the second bearing cover 315. The bearing preload applying device may be in various forms such as a spring washer 339 or a spring. The spring washer 339 may be formed in a ring shape.

[0352] The spring washer 339 is disposed axially facing the outer ring of the second bearing 132. The spring washer 339 may include a first curved portion and a second curved portion. The first curved portion is formed to protrude toward the outer ring of the second bearing 132.

[0353] The second curved portion is formed to protrude in a direction opposite to the first curved portion. The first curved portion and the second curved portion may be formed in a curved surface shape having a preset curvature.

[0354] When assembling the second bearing 132 to the inner circumference of the second bearing cover 315 , the outer circumference of the second bearing 132 and the inner circumference of the second bearing cover 315 can be fixed using adhesive or an O-ring after the spring washer 339 applies pre-pressure to the outer wheel of the second bearing 132 .

[0355] In this embodiment, if spring washer 339 applies preload to the outer ring of second bearing 132, the outer ring of second bearing 132 moves axially toward impeller 240. With the outer ring of second bearing 132 further protruding toward impeller 240 relative to the inner ring of second bearing 132, the ball bearing and the raceway of second bearing 132 are in close contact with each other without any gap. At this point, the outer and inner rings of second bearing 132 can move together in the axial direction, in close contact with the ball bearings.

[0356] The inner wheel of the first bearing 131 connected to the second bearing 132 through the rotating shaft 101 moves toward the upstream side of the first bearing 131 and is in close contact with the ball of the first bearing 131. The ball of the first bearing 131 and the track wheel can be in close contact with each other without a gap.

[0357] The outer rings of the two bearings 130 are located on the inner sides of the inner rings relative to the inner rings of the two bearings 130 in a direction approaching each other, and the bearings 130 are preloaded in an inward preload manner.

[0358] Thus, the spring washer 339 can remove the gap between the ball and the track wheel of the bearing 130 by applying preload to the outer wheel of the second bearing 132 , thereby extending the life of the bearing 130 .

[0359] An O-ring may be mounted on the outer circumference of at least one of the first bearing 131 and the second bearing 132. The O-ring may be made of an elastic rubber material. This allows the bearing 130 to move axially on the inner circumference of the bearing housings 314 and 315. The O-ring also prevents circumferential slippage.

[0360] When an O-ring is installed on the outer circumference of the second bearing 132, the O-ring allows the second bearing 132 to move axially on the inner circumference of the second bearing cover 315. Therefore, even if the preload changes during operation, the spring washer 339 can apply a constant preload to the bearing 130.

[0361] The above Figures 1 to 14 The embodiment of FIG. 4 employs a retainer and an O-ring, but in this embodiment, a case where the retainer and the O-ring are omitted is shown.

[0362] Therefore, according to this embodiment, in the structure of the reverse fan motor in which the impeller 240 is disposed between the two bearings 130, the bearings 130 are subjected to preload in an inward preload manner, so as described above Figure 14 As described in FIG. 1 a, by minimizing the rotational torque of the impeller 240 during operation, the rotating shaft 101 can be stably supported and the supporting performance of the bearing 130 can be improved.

[0363] The above Figures 1 to 12 The retainer 123 of the embodiment is a structure for applying preload to the bearing 130 in an outward preload manner, and the spring 138 is easily provided.

[0364] The above Figure 13 The retainer 223 of the embodiment applies preload to the bearing 130 in an inward preload manner, and the spring 138 is easily provided.

[0365] Furthermore, the retainers 123 and 223 do not require the O-rings 127 and 227 to be directly attached to the outer circumferential surface of the bearing 130, thereby facilitating the maintenance of the rigidity of the bearing 130. Furthermore, the retainers 123 and 223 are structured to surround the bearing 131 and be mounted so as to be accommodated within the inner circumferential surface of the retainers 123 and 223, thereby further facilitating a reduction in the diameter of the semi-load bearing 131, which does not bear the thrust load.

Claims

1. A fan motor, wherein: include: Rotation axis; An impeller is rotatably mounted on the rotating shaft to form an airflow along the axial direction; a motor, disposed upstream of the impeller with respect to the airflow direction, comprising a rotor coupled to the rotating shaft and a stator surrounding an outer circumferential surface of the rotor, the motor driving the impeller; a motor housing for accommodating the motor; a plurality of bearings supporting the rotating shaft, including a first bearing disposed on an upstream side of the motor among the plurality of bearings and a second bearing disposed on a downstream side of the motor among the plurality of bearings; a spring applying preload to the first bearing; and The stopper is arranged inside the motor cover, surrounds a portion of the second bearing facing the rotor, and restricts the second bearing from moving in a thrust direction opposite to the airflow direction.

2. The fan motor according to claim 1, wherein The second bearing is arranged adjacent to the impeller.

3. The fan motor according to claim 1, wherein The second bearing is arranged on the upstream side or the downstream side of the impeller.

4. The fan motor according to claim 1, wherein The bearing is a ball bearing; The ball bearing comprises: an inner wheel coupled to the rotating shaft; an outer wheel, arranged radially outward of the inner wheel; and The balls are arranged between the inner wheel and the outer wheel and are in rolling contact with the inner wheel and the outer wheel.

5. The fan motor according to claim 4, wherein The spring applies preload to the outer wheel of the first bearing in the thrust direction; An axial distance between an outer wheel of the first bearing and an outer wheel of the second bearing is greater than an axial distance between an inner wheel of the first bearing and an inner wheel of the second bearing.

6. The fan motor according to claim 4, wherein The spring applies pre-compression to the outer wheel of the first bearing in the direction of the airflow; An axial distance between an outer wheel of the first bearing and an outer wheel of the second bearing is smaller than an axial distance between an inner wheel of the first bearing and an inner wheel of the second bearing.

7. The fan motor according to claim 6, wherein: The motor and the impeller are arranged between the first bearing and the second bearing.

8. The fan motor according to claim 1, wherein The motor housing comprises: a first bearing cover, disposed on the upstream side of the motor and accommodating the first bearing; and The second bearing cover is arranged on the downstream side of the motor and accommodates the second bearing.

9. The fan motor according to claim 8, wherein Also included is a retaining member, the retaining member being disposed on the inner side of the first bearing cover and supporting the spring; The retaining member comprises: a spring inner wall portion, surrounding the inner side of the spring and coupled to the outer peripheral surface of the first bearing; a spring outer wall portion, surrounding the outer side of the spring and arranged facing the inner peripheral surface of the first bearing cover; and a connecting portion connecting one end of the inner wall portion of the spring and one end of the outer wall portion of the spring in a direction opposite to the motor; The motor cover further includes a spring support portion, which is arranged toward the motor, protrudes from the inner peripheral surface of the first bearing cover, and supports one end of the spring facing the rotor.

10. The fan motor according to claim 9, wherein The retainer further includes an O-ring mounted on the outer peripheral surface of the spring outer wall portion and movably contacting the inner peripheral surface of the first bearing cover toward the thrust direction.

11. The fan motor according to claim 8, wherein The motor cover further includes an alignment guide that is formed to protrude from an inner end of the spring support portion toward the spring inner wall portion and is arranged to overlap with the spring inner wall portion in an axial direction.

12. The fan motor according to claim 8, wherein The motor housing comprises: a motor support portion, surrounding an outer peripheral surface of the motor and extending in an axial direction to support the motor; a first bridge portion extending radially from an outer peripheral surface of the first bearing cover toward an upstream end portion of the motor support portion; and The second bridge portion extends radially from the outer peripheral surface of the second bearing cover toward a downstream end portion of the motor support portion.

13. The fan motor according to claim 12, wherein: The motor support parts are provided in plurality, and the plurality of motor support parts are arranged spaced apart in the circumferential direction along the peripheral edge of the outer peripheral surface of the motor; The motor cover further includes an outer ring portion extending along a circumferential direction and connecting downstream end portions of a plurality of the motor support portions.

14. The fan motor according to claim 8, wherein The stopper is arranged toward the motor and is formed to protrude from the inner peripheral surface of the second bearing cover so that the one surface of the second bearing is locked to the stopper.

15. The fan motor according to claim 1, wherein The diameter of the second bearing is greater than or equal to the diameter of the first bearing.

16. The fan motor according to claim 1, wherein The impeller further includes blades that are arranged on the downstream side of the impeller and guide the airflow.

17. The fan motor according to claim 16, wherein Also includes: an impeller cover, coupled to the downstream end of the motor cover, and accommodating the impeller; and The blade cover is coupled to the downstream end portion of the impeller cover and supports the blades.

18. The fan motor according to claim 17, wherein The upstream end of the impeller cover is coupled to the inner circumferential surface of the downstream end of the motor cover, and the downstream end of the impeller cover is coupled to the inner circumferential surface of the upstream end of the blade cover.

19. The fan motor according to claim 16, wherein The blades are composed of single-stage blades or double-stage blades.

20. The fan motor according to claim 16, wherein The blade cover supporting the blade comprises: a blade outer wall portion connected to the radially outer end portion of the blade and coupled to the downstream end portion of the impeller cover; and The blade inner wall portion is connected to the radial inner end portion of the blade and is arranged on the downstream side of the impeller.

Images