Blower

Abstract

The invention provides a blower capable of increasing the rotation speed of an impeller. A blower (1) is provided with: a shaft (10); a sleeve (81); an impeller (56) that is rotatably supported on one side in the axial direction of the shaft (10) and generates an air flow from the one side in the axial direction toward the other side by rotation; a first ball bearing (20) including: an inner ring (21) supported on a portion of the shaft (10) close to the impeller (56); and an outer ring (22) fixed to the inner peripheral surface (81i) of the sleeve (81). A second ball bearing (30) having an inner ring (31) supported by a portion of the shaft (10) farther from the impeller (56) than the inner ring (21); a first flange section (28) that is supported by a portion of the shaft (10) between the inner ring (21) and the inner ring (31) and that protrudes radially outward from the shaft (10); and a first spring (40) disposed between the first flange portion (28) and the inner ring (31). The first flange portion (28) presses the inner ring (21) from the other side toward the one side when the impeller (56) rotates.

Description

Technical Field

[0001] The invention relates to a blower. Background Art

[0002] A device is known that includes a rotating shaft rotatably supported by two ball bearings and an impeller mounted on the rotating shaft and rotating together with the rotating shaft (for example, refer to Patent Document 1 below). In the device described in Patent Document 1, an air flow is generated from the impeller side toward the opposite side of the impeller in the axial direction by the rotation of the impeller. In addition, in contrast, a thrust is generated from the opposite side of the impeller toward the impeller side with respect to the rotating shaft or the like.

[0003] In the device described in Patent Document 1, a preload spring is arranged on the impeller side more closely than the ball bearing on the impeller side. In the device described in Patent Document 1, when the impeller rotates, the ball bearing on the impeller side is subjected to a force applied in the direction opposite to the direction of action of the thrust (from the impeller side toward the opposite side of the impeller) by the preload spring, and is preloaded. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-210878 Summary of the invention Problems to be solved by the invention

[0005] In general, the thrust increases as the rotation speed of the impeller increases. In the device described in the above-mentioned patent document 1, a force is applied to the ball bearing close to the impeller side in the direction opposite to the direction in which the thrust acts by a preload spring. Therefore, in the device described in the above-mentioned patent document 1, in order to always apply preload to the ball bearing when the impeller rotates, it is necessary to increase the force of the preload spring as the rotation speed of the impeller increases. However, in general, a maximum value (specified value) is specified for the surface pressure applied to the ball bearing. That is, there is an upper limit to the preload that can be applied to the ball bearing. Therefore, in the past, due to such restrictions on the ball bearing, it was difficult to increase the rotation speed of the impeller.

[0006] Therefore, the present invention provides a blower capable of increasing the rotation speed of an impeller as one of the problems. Solutions for solving problems

[0007] The blower of the present invention comprises: a shaft; a sleeve accommodating a part of the shaft therein; an impeller rotatably supported on one side of the shaft in the axial direction, and generating an air flow from the one side of the shaft in the axial direction toward the other side of the shaft in the axial direction by rotation; a first ball bearing, which comprises: an inner ring supported on a portion of the shaft close to the impeller; and an outer ring fixed to the inner peripheral surface of the sleeve; a second ball bearing, whose inner ring is supported on a portion of the shaft farther from the impeller than the inner ring of the first ball bearing; a first flange portion supported on the shaft between the inner ring of the first ball bearing and the inner ring of the second ball bearing, and extending from the radial outer side perpendicular to the axial direction; and a first spring disposed between the first flange portion and the inner ring of the second ball bearing. In the blower, when the impeller rotates, the first flange portion pushes the inner ring of the first ball bearing from the other side toward the one side.

[0008] Another blower of the present invention comprises: a shaft; a sleeve, which accommodates a part of the shaft; an impeller, which is rotatably supported on one side of the shaft in the axial direction, and generates an air flow from the one side of the shaft to the other side of the shaft in the axial direction by rotation; a first ball bearing, which includes: an inner ring, which is supported on a portion of the shaft close to the impeller; and an outer ring, which is arranged on the inner periphery of the sleeve; a second ball bearing, whose inner ring is supported on a portion of the shaft that is farther away from the impeller than the inner ring of the first ball bearing; a first flange portion, which is supported on the shaft between the inner ring of the first ball bearing and the inner ring of the second ball bearing, and extends from the outer side of the radial direction perpendicular to the axial direction; and a first spring, which is arranged between the first flange portion and the inner ring of the second ball bearing, and an extension portion protruding toward the inner side of the radial direction is provided on the inner periphery of the sleeve, and the end of the one side of the first ball bearing abuts against the extension portion, and the first flange portion pushes the inner ring of the first ball bearing from the other side toward the one side when the impeller rotates.

[0009] These blowers may further include at least one of the following structures.

[0010] The impeller may form a part of a rotor that rotates relative to the sleeve as the shaft rotates, and a maximum value of a load applied by the first spring may be smaller than a load applied by the rotor.

[0011] The outer ring of the second ball bearing may be restricted from moving in the axial direction.

[0012] Alternatively, the air blower may further include a fixing portion, which is fixed to the inner circumferential surface of the sleeve and extends inwardly in the radial direction, and the sleeve includes a step portion protruding inwardly in the radial direction at a portion closer to the one side than the fixing portion, and the outer ring of the second ball bearing is clamped by the step portion and the fixing portion to restrict movement in the axial direction.

[0013] Alternatively, the blower may further include: a second flange portion supported on the shaft at a portion closer to the other side than the inner ring of the second ball bearing and extending from the axial direction to the outer side in the radial direction; and a second spring disposed between the second flange portion and the inner ring of the second ball bearing. In this case, the impeller may form a part of a rotor that rotates relative to the sleeve as the shaft rotates, and when the deflection of the first spring and the second spring changes by the axial clearance of the first ball bearing and / or the second ball bearing, the change in load ((applied force)) applied by the first spring and the second spring is greater than the weight of the inner ring of the second ball bearing.

[0014] Alternatively, the blower may further include a second flange portion, the second flange portion being supported on a portion of the shaft closer to the other side than the inner ring of the second ball bearing and extending from the axial direction to the outer side in the radial direction, the inner peripheral surface of the sleeve including a step portion protruding inward in the radial direction at a portion between the outer ring of the first ball bearing and the outer ring of the second ball bearing in the axial direction, a third spring being arranged between the step portion in the axial direction and the outer ring of the second ball bearing, and the second flange portion pressing the inner ring of the second ball bearing from the other side toward the one side when the impeller rotates. In this case, the impeller may form a part of a rotor that rotates relative to the sleeve as the shaft rotates, and the maximum value of the load applied by the first spring and the maximum value of the load applied by the third spring are respectively smaller than the load applied by the rotor.

[0015] Furthermore, in the above-mentioned blower, a washer may be supported on the surface on the other side of the impeller, and the shaft may pass through the washer. Effects of the Invention

[0016] According to the present invention, there is provided a blower capable of increasing the rotation speed of an impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view in the axial direction of the air blower showing the first embodiment of the present invention. Figure 2 When the impeller is stationary Figure 1 The bearing device is shown in an enlarged and schematic cross-sectional view. Figure 3 When the impeller rotates Figure 1 The bearing device is shown in an enlarged and schematic cross-sectional view. Figure 4 It is a cross-sectional view in the axial direction of the air blower showing the second embodiment of the present invention. Figure 5 When the impeller is stationary Figure 4 The bearing device is shown in an enlarged and schematic cross-sectional view. Figure 6 When the impeller rotates Figure 4 The bearing device is shown in an enlarged and schematic cross-sectional view. Figure 7 It is a cross-sectional view in the axial direction of the air blower showing the third embodiment of the present invention. Figure 8 When the impeller is stationary Figure 7 The bearing device is shown in an enlarged and schematic cross-sectional view. Fig. 9 When the impeller rotates Figure 7 The bearing device is shown in an enlarged and schematic cross-sectional view. Fig.10 It is a cross-sectional view in the axial direction of the air blower showing the fourth embodiment of the present invention. Fig.11 When the impeller is stationary Fig.10 The bearing device is shown in an enlarged and schematic cross-sectional view. DETAILED DESCRIPTION

[0018] The following, with the attached Figure 1 The following examples illustrate the method for implementing the blower of the present invention. The following examples illustrate the embodiments for facilitating the understanding of the present invention and are not intended to limit the interpretation of the present invention. The present invention can be changed and improved according to the following embodiments without departing from its main purpose. In addition, in the above-mentioned drawings, for ease of understanding, the size of each component is sometimes shown in an exaggerated or reduced manner or the hatching is omitted.

[0019] (First Embodiment) Figure 1 2 is a cross-sectional view showing the axial direction of the blower according to the present embodiment. Figure 1 As shown, the blower 1 includes a housing 11 , a bearing device 80 , a stator 70 , and a rotor 50 as main components.

[0020] The bearing device 80 includes a tubular (cylindrical in the present embodiment) sleeve 81 , the shaft 10 , the first ball bearing 20 , the second ball bearing 30 , the washer 29 , the first flange portion 28 , the first spring 40 , and the fixing portion 60 .

[0021] The sleeve 81 is made of metal, for example, and accommodates the first ball bearing 20 , the second ball bearing 30 , the first flange portion 28 , the first spring 40 , the fixing portion 60 , a part of the shaft 10 , and the like therein.

[0022] The shaft 10 passes through the center of the sleeve 81 in the radial direction. A portion of the shaft 10 becomes a protrusion 10a that protrudes outward from the inside of the sleeve 81. In the present embodiment, the blower 1 is configured in a concentric shape in such a way that the shaft 10 is located at the center of the radial direction. However, the positional relationship of the shaft 10 and the like in the blower 1 is not limited to the concentric shape. The long dimension direction of the shaft 10 is the axial direction of the blower 1, and the axial direction is perpendicular to the above-mentioned radial direction. It should be noted that, hereinafter, the side facing the protrusion 10a side in the axial direction is sometimes referred to as "upper", "above", "upper side" or "one side", and the side facing the opposite side of the protrusion 10a side is sometimes referred to as "lower", "below", "lower side" or "the other side". In addition, the side close to the shaft 10 in the radial direction is sometimes referred to as "inner" or "inner side", and the side away from the shaft 10 is sometimes referred to as "outer" or "outer side".

[0023] The first ball bearing 20 is mounted near the protrusion 10a of the shaft 10 (i.e., one side of the shaft 10). In the axial direction, the protrusion 10a is located above the first ball bearing 20. The second ball bearing 30 is mounted near the lower end of the shaft 10 (i.e., the other side of the shaft 10). The second ball bearing 30 is located below the first ball bearing 20. The first ball bearing 20 and the second ball bearing 30 support the shaft 10 rotatably.

[0024] The washer 29 is located above the first ball bearing 20, and the shaft 10 passes through a hole formed in the radial center of the washer 29. The first flange portion 28 is located below the first ball bearing 20 and is supported by the shaft 10. The first spring 40 is disposed between the first flange portion 28 and the second ball bearing 30 in the axial direction. The fixing portion 60 is disposed below the second ball bearing 30.

[0025] It should be noted that the bearing device 80 will be described in more detail later.

[0026] The housing 11 has a cylindrical shape, for example, when viewed from the axial direction, it can be roughly square, roughly rectangular or circular. The internal space of the housing 11 is formed as a wind tunnel for the air flow to flow from the upper side to the lower side along the axial direction. That is, an air intake port 11i for sucking air into the internal space of the housing 11 is formed at the end 11u on the upper side of the housing 11, and an exhaust port 11o for letting the air flow out is formed at the end 11d on the lower side of the housing 11. The bearing device 80, the stator 70, the rotor 50, etc. are accommodated in the internal space of the housing 11. The housing 11 includes a side wall 12, a base portion 13, and fixed blades 14.

[0027] The side wall 12 is located radially outside the rotor 50 and surrounds the rotor 50. The side wall 12 is connected to the upper end 11u of the housing 11. The side wall 12 has a cylindrical shape centered on the shaft 10 and is arranged with a gap between the side wall 12 and the rotor 50. The side wall 12 also has a function of protecting the rotor 50, the bearing device 80, etc. arranged therein.

[0028] The stationary blades 14 are composed of a plurality of stationary blades. The stationary blades 14 connect the side wall 12 and the base portion 13 in the radial direction.

[0029] The base portion 13 includes: a disc-shaped bottom portion 13a perpendicular to the axial direction; a cylindrical outer peripheral wall 13b extending axially upward by a predetermined length from the outer end portion of the bottom portion 13a; and a cylindrical boss portion 13c protruding axially upward by a predetermined length from the inner end portion of the bottom portion 13a. The outer peripheral wall 13b and the boss portion 13c are concentric with respect to the shaft 10.

[0030] The outer peripheral surface of the outer peripheral wall 13b is integrally formed with the fixed vanes 14. That is, the outer peripheral wall 13b is supported by the side wall 12 via the fixed vanes 14. The sleeve 81 of the bearing device 80 is mounted on the inner peripheral surface of the boss portion 13c by press fitting, for example.

[0031] The side wall 12, the base 13 and the fixed blade 14 of the housing 11 can be formed as one piece by injection molding of a synthetic resin (e.g., polybutylene terephthalate resin). In addition, the fixed blade 14 connecting the side wall 12 and the base 13 can also be replaced by a plurality of spokes composed of rod-shaped parts.

[0032] Next, the stator 70 will be described.

[0033] The stator 70 includes a stator core 71 , an insulator 72 , and a plurality of coils 73 as main components.

[0034] In the present embodiment, the stator core 71 is formed by a laminated body formed by laminating cores of a plurality of electromagnetic steel plates made of soft magnetic material. The stator core 71 is located outside the sleeve 81 of the bearing device 80. In the present embodiment, a circular opening 71h is formed on the inner circumferential surface of the stator core 71. The sleeve 81 penetrates the opening 71h of the stator core 71 in the axial direction. The sleeve 81 is assembled to the stator core 71 by, for example, being pressed into the opening 71h of the stator core 71. It should be noted that the stator core 71 can also be fixed to the sleeve 81 using an adhesive.

[0035] The insulator 72 is made of an insulating material, attached to the stator core 71, and covers a portion of the stator core 71. The outer peripheral surface 71o of the stator core 71 is exposed from the insulator 72. The plurality of coils 73 are respectively wound around the stator core 71 with predetermined intervals in the circumferential direction of the stator core 71 through the insulator 72. Therefore, the stator core 71 and the plurality of coils 73 are insulated via the insulator 72.

[0036] Next, the rotor 50 will be described.

[0037] The rotor 50 includes an impeller 56 , a rotor yoke 52 , a magnet 51 , and a bushing 53 as main components.

[0038] The impeller 56 includes a hub 54 and a plurality of blades 55 provided along the circumferential direction on the outer peripheral surface of the hub 54. The hub 54 and the plurality of blades 55 can be integrally formed by, for example, injection molding a synthetic resin (for example, polybutylene terephthalate resin containing glass fiber).

[0039] The hub 54 has a cup-like shape with a bottom cross section that is roughly inverted U-shaped, and includes a plate-like base 54a perpendicular to the axial direction and a cylindrical (cylindrical) side wall 54b extending roughly in the axial direction from the outer end of the base 54a. The hub 54 is arranged with the base 54a facing upward. The hub 54 covers the rotor yoke 52, the magnet 51, the bushing 53, the stator 70, the bearing device 80, etc. from the upper side. In this way, the hub 54 prevents foreign matter from entering the position closer to the inside of the hub 54.

[0040] The plurality of blades 55 have substantially the same shape and extend outward from the side wall 54b of the hub 54. The plurality of blades 55 are arranged substantially at equal intervals in the circumferential direction of the side wall 54b of the hub 54. The plurality of blades 55 are formed so as to generate an air flow that flows axially from the upper side to the lower side in the internal space of the housing 11 when the impeller 56 rotates.

[0041] The bushing 53 is made of, for example, a soft magnetic material. A through hole 53h is formed in the radial center of the bushing 53 so as to penetrate the bushing 53 in the axial direction. The shaft 10 is assembled to the bushing 53 by, for example, pressing the protrusion 10a of the shaft 10 into the through hole 53h. In addition, a recess 53c that is recessed inward is formed in the upper portion of the bushing 53.

[0042] The rotor yoke 52 has a cup-like shape with a bottom cross-section that is roughly inverted U-shaped, and is made of, for example, a soft magnetic material. The rotor yoke 52 includes a plate-like base 52a perpendicular to the axial direction and a tubular (cylindrical) side wall 52b extending roughly along the axial direction from the outer end of the base 52a. The rotor yoke 52 is arranged with the base 52a facing upward. The rotor yoke 52 covers the magnet 51, the stator 70, the bearing device 80, etc. from the upper side. In this way, the rotor yoke 52 prevents foreign matter from entering a position closer to the inside than the rotor yoke 52.

[0043] A circular hole is formed in the radial center of the base 52a of the rotor yoke 52 when viewed from the axial direction. The hole is defined by the inner circumferential surface 52ai of the base 52a. The inner circumferential surface 52ai and its vicinity in the base 52a are fixed by riveting to the upper part of the bushing 53. As a result, the above-mentioned recessed portion 53c is formed in the upper part of the bushing 53. In addition, the upper part of the outer circumferential surface of the side wall 52b of the rotor yoke 52 is fixed to the inner circumferential surface of the side wall 54b of the hub 54 of the impeller 56, for example, using an adhesive. In this way, the rotor yoke 52 is fixed to the inner circumferential surface of the impeller 56.

[0044] The magnet 51 is formed into a ring shape when viewed from the axial direction, and is formed into a cylindrical shape in the present embodiment. The outer peripheral surface of the magnet 51 is fixed to the inner peripheral surface of the side wall 52b of the rotor yoke 52, for example, via an adhesive. The magnet 51 is magnetized alternately into N poles and S poles in the circumferential direction. In the radial direction, the inner peripheral surface 51i of the magnet 51 is located outside the stator 70 and faces the outer peripheral surface 71o of the stator core 71 across an air gap.

[0045] In the blower 1, when current is supplied to the plurality of coils 73, magnetic interaction is generated between the outer circumferential surface 71o of the stator core 71 and the inner circumferential surface 51i of the magnet 51, and a magnetic circuit is formed in the blower 1. The shaft 10 rotates through the magnetic circuit, and as the shaft 10 rotates, the rotor 50 including the impeller 56 rotates around the shaft 10. That is, the rotor 50 including the impeller 56 rotates relative to the bearing device 80 including the stator 70 and the sleeve 81. In this way, the blower 1 is configured as an outer rotor type. Then, by the rotation of the impeller 56, an air flow is generated that flows axially from the upper side (one side) to the lower side (the other side) in the internal space of the housing 11.

[0046] Next, the bearing device 80 will be described in more detail.

[0047] like Figure 1 As shown, in the bearing device 80, the first ball bearing 20 is arranged near the protruding portion 10a of the shaft 10. Figure 1As shown, there is a base 54a of the hub 54 on the upper side of the protrusion 10a. Therefore, the first ball bearing 20 is located closer to the base portion 54a of the hub 54 than the second ball bearing 30. That is, the first ball bearing 20 is located closer to the impeller 56 than the second ball bearing 30.

[0048] Figure 2 2 is a cross-sectional view schematically showing an enlarged state of the bearing device 80 when the impeller 56 is stationary. Figure 2 The state of the bearing device 80 when the impeller 56 is stationary is shown in the case where the blower 1 is arranged so that the protruding portion 10 a of the shaft 10 faces upward in the vertical direction.

[0049] like Figure 2 As described above, the first ball bearing 20 includes an inner ring 21, an outer ring 22, and a plurality of rolling bodies (balls) 23. The shaft 10 is inserted into a through hole defined by the inner circumferential surface of the inner ring 21. The inner ring 21 is supported by the shaft 10 that passes through the through hole of the inner ring 21. The inner ring 21 is supported by a portion of the shaft 10 that is close to the impeller 56. A recessed portion 21c that is recessed inwardly in an arc shape when viewed from the radial direction is formed at the center in the axial direction of the outer circumferential surface 21o of the inner ring 21. The outer circumferential surface of the outer ring 22 is fixed to the inner circumferential surface 81i of the sleeve 81 using, for example, an adhesive. A recessed portion 22c that is recessed outwardly in an arc shape when viewed from the radial direction is formed at the center in the axial direction of the inner circumferential surface 22i of the outer ring 22. The plurality of rolling bodies 23 are supported by being sandwiched between the recessed portion 21c of the inner ring 21 and the recessed portion 22c of the outer ring 22. In this way, by interposing the plurality of rolling elements 23 between the inner ring 21 and the outer ring 22 , the inner ring 21 rotates together with the shaft 10 relative to the outer ring 22 fixed to the sleeve 81 .

[0050] The second ball bearing 30 has the same structure as the first ball bearing 20. The shaft 10 is inserted into the through hole defined by the inner circumferential surface of the inner ring 31 of the second ball bearing 30. The inner ring 31 is supported by the shaft 10 that penetrates the through hole of the inner ring 31. The inner ring 31 is supported by a portion of the shaft 10 that is farther from the impeller 56 than the inner ring 21. The outer circumferential surface of the outer ring 32 is in substantially surface contact with the inner circumferential surface 81i of the sleeve 81. The plurality of rotors 33 are sandwiched and supported by the recessed portion 31c of the inner ring 31 and the recessed portion 32c of the outer ring 32. In this way, by sandwiching the plurality of rotors 33 between the inner ring 31 and the outer ring 32, the inner ring 31 rotates relative to the outer ring 32 together with the shaft 10.

[0051] It should be noted that, in this embodiment, the outer ring 22 of the first ball bearing 20 is fixed to the sleeve 81 by bonding, but the inner ring 21 of the first ball bearing 20 is clearance-fitted with the inner ring 31 and the outer ring 32 of the second ball bearing 30. Specifically, the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30 are clearance-fitted with the shaft 10, respectively, and the outer ring 32 of the second ball bearing 30 is clearance-fitted with the sleeve 81.

[0052] The sleeve 81 includes a step portion 81P protruding radially inward. The step portion 81P is located between the outer ring 22 of the first ball bearing 20 and the outer ring 32 of the second ball bearing 30 in the axial direction. In addition, in the radial direction, the end surface 81Pe of the step portion 81P is located at the same position as the inner peripheral surface 22i of the outer ring 22 of the first ball bearing 20 or at a position outside the inner peripheral surface 22i, and is located at the same position as the inner peripheral surface 32i of the outer ring 32 of the second ball bearing 30 or at a position outside the inner peripheral surface 32i. The upper surface 81Pu of the step portion 81P contacts the lower surface 22d of the outer ring 22 of the first ball bearing 20. The lower surface 81Pd of the step portion 81P contacts the upper surface 32u of the outer ring 32 of the second ball bearing 30. It should be noted that in the present embodiment, the step portion 81P is integrated with the sleeve 81, but it may be composed of another substantially cylindrical member fixed to the inner peripheral surface 81i of the sleeve 81 by bonding or other methods.

[0053] The fixing portion 60 is located on the lower side (the other side) than the step portion 81P. In other words, the step portion 81P is located on the upper side (one side) than the fixing portion 60. The fixing portion 60 is fixed to the inner circumferential surface 81i of the sleeve 81 and extends inward. In the present embodiment, the fixing portion 60 includes: a washer 62 fixed to the inner circumferential surface 81i of the sleeve 81 and extending inward; and a spacer 61 arranged on the upper surface of the washer 62. The lower surface 32d of the outer ring 32 of the second ball bearing 30 contacts the upper surface of the spacer 61. The spacer 61 and the washer 62 are respectively annular, and the shaft 10 is inserted into the inner side of the inner circumferential surface of the spacer 61 and the inner side of the inner circumferential surface of the washer 62. It should be noted that the fixing portion 60 is not limited to this, and for example, it can also be composed of only the washer 62, or it can also be composed of only the spacer 61 fixed to the inner circumferential surface 81i.

[0054] In the present embodiment, the outer ring 32 of the second ball bearing 30 is restricted from moving in the axial direction by being clamped by the step portion 81P and the fixing portion 60. It should be noted that the outer ring 32 of the second ball bearing 30 may be bonded to the inner peripheral surface 81i of the sleeve 81 by using an adhesive or the like to restrict the movement of the outer ring 32 in the axial direction.

[0055] The first flange portion 28 is fixed to a portion between the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30 in the shaft 10, and extends radially outward from the shaft 10. In the present embodiment, the first flange portion 28 is a washer, which is inserted into a groove formed in the outer peripheral surface 10o of the shaft 10, and is thereby supported by the shaft 10. It should be noted that the configuration of the first flange portion 28 is not limited thereto, and for example, it may be a portion integrally formed with the shaft 10 in a flange shape. In the present embodiment, the first flange portion 28 is located directly below the inner ring 21 of the first ball bearing 20, and when the impeller 56 is stationary, it contacts the lower surface 21d of the inner ring 21 of the first ball bearing 20, but it may not contact.

[0056] The first spring 40 is disposed between the lower surface of the first flange portion 28 and the upper surface 31u of the inner ring 31 of the second ball bearing 30. The shaft 10 passes through the inside of the first spring 40. That is, the first spring 40 surrounds a portion of the outer peripheral surface 10o of the shaft 10.

[0057] In the present embodiment, the washer 29 is supported by the shaft 10. For example, the washer 29 is supported by the shaft 10 by being fitted into a groove formed in the outer peripheral surface 10o of the shaft 10. The shaft 10 is inserted into the through hole 53h of the bushing 53.

[0058] When the fan 1 is arranged so that the protruding portion 10a of the shaft 10 faces upward in the vertical direction, when the impeller 56 is stationary, Figure 2 As shown by the middle arrow, the load F1 applied by the rotor 50 acts on the shaft 10 from the upper side to the lower side. Then, as a result, the shaft 10 and the inner ring 21 of the first ball bearing 20 supported by the shaft 10 move downward. As described above, the outer ring 22 of the first ball bearing 20 is fixed to the sleeve 81. Therefore, the inner ring 21 of the first ball bearing 20 is located at the lower side relative to the outer ring 22. Therefore, when the impeller 56 is stationary, the rotating body 23 of the first ball bearing 20 contacts the upper area of ​​the recess 21c of the inner ring 21 and the lower area of ​​the recess 22c of the outer ring 22. That is, when the impeller 56 is stationary, as shown in FIG. Figure 2 As shown by the dashed line in , preload acts on the first ball bearing 20 while the straight line connecting the contact points of the inner ring 21 and the outer ring 22 with the rolling element 23 is inclined with respect to the radial direction so as to go radially outward as it goes downward.

[0059] Since the first spring 40 is arranged on the upper surface 31u of the inner ring 31 of the second ball bearing 30, as the shaft 10 moves downward due to the load F1 applied by the rotor 50, the inner ring 31 supported by the shaft 10 also moves downward. As described above, the axial movement of the outer ring 32 of the second ball bearing 30 is restricted. Therefore, the inner ring 31 of the second ball bearing 30 is located at the lower side relative to the outer ring 32. Therefore, when the impeller 56 is stationary, the rotating body 33 of the second ball bearing 30 contacts the upper area of ​​the recess 31c of the inner ring 31 and the lower area of ​​the recess 32c of the outer ring 32. That is, when the impeller 56 is stationary, as Figure 2 As shown by the dashed line in , preload acts on the second ball bearing 30 while the straight line connecting the contact points between the inner ring 31 and the outer ring 32 and the rolling element 33 is inclined with respect to the radial direction so as to go radially outward as it goes downward.

[0060] Thus, in the bearing device 80, when the impeller 56 is stationary, the preload applied to the first ball bearing 20 and the second ball bearing 30 becomes the following parallel combination: the preload is applied in a state where the straight line connecting the contact points of the respective inner rings and outer rings with the rotating body is inclined relative to the radial direction in a manner toward the radial outside as it goes downward.

[0061] Furthermore, the first spring 40 contacts the first flange portion 28 supported by the shaft 10, and does not contact the first ball bearing 20. Therefore, the urging force of the first spring 40 is prevented from being transmitted to the first ball bearing 20 by the first flange portion 28 supported by the shaft 10. That is, when the impeller 56 is stationary, substantially only the preload caused by the load F1 applied by the rotor 50 is applied to the first ball bearing 20.

[0062] Next, the bearing device 80 when the impeller 56 rotates will be described.

[0063] Figure 3 2 is a cross-sectional view schematically showing the state of the bearing device 80 when the impeller 56 rotates in an enlarged manner. Figure 3 The diagram shows a state of the bearing device 80 when the impeller 56 rotates in a case where the blower 1 is arranged so that the protruding portion 10 a of the shaft 10 faces upward in the vertical direction.

[0064] like Figure 3 As shown by the middle arrow, when the blower 1 is arranged so that the protrusion 10a of the shaft 10 faces the upper side in the vertical direction, when the impeller 56 rotates, in addition to the load F1 applied from the upper side to the lower side by the rotor 50, a thrust F2 acts on the shaft 10. The thrust F2 acts from the lower side (the other side) toward the upper side (one side) due to the air flow from the upper side to the lower side generated by the rotation of the impeller 56.

[0065] Specifically, when the rotation speed of the impeller 56 increases (when the impeller 56 rotates at a high speed), the thrust F2 is greater than the load F1 applied by the rotor 50, and as a result, the shaft 10 and the first flange portion 28 supported by the shaft 10 move upward due to the thrust F2. Moreover, as a result of the upward movement of the first flange portion 28, the inner ring 21 of the first ball bearing 20 is pushed from the lower side (the other side) toward the upper side (one side) by the first flange portion 28 that contacts the lower surface 21d of the inner ring 21 and moves upward. The outer ring 22 of the first ball bearing 20 is fixed to the sleeve 81. Therefore, the inner ring 21 is located on the upper side relative to the outer ring 22. Therefore, when the impeller 56 rotates at a high speed, the rotating body 23 of the first ball bearing 20 contacts the lower area of ​​the recess 21c of the inner ring 21 and the upper area of ​​the recess 22c of the outer ring 22. That is, when the impeller 56 rotates at a high speed, as shown in FIG. Figure 3 As shown by the dashed line in , preload acts on the first ball bearing 20 while the straight line connecting the contact points of the inner ring 21, the outer ring 22 and the rolling element 23 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0066] It should be noted that the rotation speed of the high-speed rotation of the impeller 56 is not particularly limited, and may be, for example, 8000 rpm or more, 10000 rpm or more, 15000 rpm or more, or 30000 rpm or more.

[0067] When the impeller 56 rotates at high speed, the inner ring 31 of the second ball bearing 30 supported by the shaft 10 moves upward together with the shaft 10 due to the thrust F2. However, along with this, the force of the inner ring 31 pushing the first spring 40 also increases, so the first spring 40 rebounds and pushes the inner ring 31 downward. As a result, the inner ring 31 is maintained in the lower position. The axial movement of the outer ring 32 of the second ball bearing 30 is restricted, so the inner ring 31 is relatively located at the lower side with respect to the outer ring 32. Therefore, when the impeller 56 rotates at high speed, the rotating body 33 of the second ball bearing 30 contacts the upper area of ​​the recess 31c of the inner ring 31 and the lower area of ​​the recess 32c of the outer ring 32. That is, when the impeller 56 rotates at high speed, as shown in FIG. Figure 3 As shown by the dashed line in , preload acts on the second ball bearing 30 while the straight line connecting the contact points of the inner ring 31, the outer ring 32 and the rolling element 33 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0068] As described above, in the bearing device 80 , when the impeller 56 rotates at a high speed, the preload applied to the first ball bearing 20 and the second ball bearing 30 becomes a so-called positive combination.

[0069] It should be noted that, although not particularly limited, in the bearing device 80 of the present embodiment, the maximum value of the load (applied force) applied by the first spring 40 is smaller than the load F1 applied by the rotor 50 when the blower 1 is arranged in a manner such that the protrusion 10a of the shaft 10 faces the upper side in the vertical direction. Here, as described above, the thrust F2 applied by the rotor 50 when the impeller 56 rotates at a high speed is greater than the load F1 applied by the rotor 50. That is, in the present embodiment, the load applied by the first spring 40 is smaller than the thrust F2 during high-speed rotation. Therefore, in the bearing device 80, especially during high-speed rotation, the applied force applied by the first spring 40 is suppressed from acting in a manner to overcome the thrust F2.

[0070] As described above, the blower 1 of the present embodiment comprises: a shaft 10; a sleeve 81, which accommodates a portion of the shaft 10 (roughly except for the protrusion 10a) therein; an impeller 56, which is rotatably supported on one side of the shaft 10 in the axial direction, and generates an air flow from one side in the axial direction toward the other side in the axial direction by rotation; a first ball bearing 20, which includes: an inner ring 21, which is supported on a portion of the shaft 10 close to the impeller 56; and an outer ring 22, which is fixed to the inner circumferential surface 81i of the sleeve 81; a second ball bearing 30, whose inner ring 31 is supported on a portion of the shaft 10 that is farther away from the impeller 56 than the inner ring 21 of the first ball bearing 20; a first flange portion 28, which is supported on the shaft 10 between the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30, and extends radially outward from the shaft 10; and a first spring 40, which is arranged between the first flange portion 28 and the inner ring 31 of the second ball bearing 30. Furthermore, in the blower 1 , the first flange portion 28 presses the inner ring 21 of the first ball bearing 20 from the other side toward one side when the impeller 56 rotates.

[0071] The first ball bearing 20 is located near the impeller 56 and away from the base portion 13 of the housing 11 supporting the bearing device 80. Therefore, when the impeller 56 rotates at a high speed, a large moment caused by the rotation of the impeller 56 acts on the first ball bearing 20. However, according to such a blower 1, as described above, when the impeller 56 rotates, the first ball bearing 20 can be preloaded only by the thrust from the lower side to the upper side. That is, in the blower 1, even when the impeller 56 is rotated at a high speed, it is not necessary to apply the spring force in a manner that overcomes the thrust, so that an excessive surface pressure exceeding a predetermined value is suppressed from being applied to the first ball bearing 20. Therefore, according to the blower 1, even when a relatively large moment acts on the first ball bearing 20 due to the high-speed rotation of the impeller 56, it is possible to suppress the application of an excessive load to the first ball bearing 20 and to apply a preload to the first ball bearing 20.

[0072] On the other hand, when the blower 1 is arranged so that the protruding portion 10a of the shaft 10 faces upward in the vertical direction, the second ball bearing 30 located at the lower side is located away from the impeller 56 and is located close to the base portion 13 of the housing 11 that supports the bearing device 80. Therefore, even when the impeller 56 rotates at a high speed, a relatively small moment acts on the second ball bearing 30. Therefore, even when the second ball bearing 30 is preloaded by the urging force of the first spring 40 when the impeller 56 rotates at a high speed, the load on the second ball bearing 30 is relatively small.

[0073] As described above, according to the blower 1 , even when the impeller 56 rotates at a high speed, preload can be applied to both the first ball bearing 20 and the second ball bearing 30 without applying an excessive load, so the rotation speed of the impeller 56 can be increased.

[0074] Furthermore, in the blower 1, as described above, when the impeller 56 is stationary, only the load F1 applied by the rotor 50 acts on the first ball bearing 20 (that is, the force applied by the spring does not act on the first ball bearing 20), so the preload applied to the first ball bearing 20 is reduced. In this way, in the blower 1, since the resistance when the stationary impeller 56 tries to rotate is reduced, the impeller 56 can start rotating more smoothly.

[0075] Furthermore, in the blower 1, as described above, the upper surface 21u of the inner ring 21 of the first ball bearing 20 is in contact with the washer 29. Therefore, the upper surface 21u of the inner ring 21 and the lower surface 53d of the bushing 53 do not move relative to each other (e.g., rotate) in a state of direct contact, thereby suppressing the generation of noise or the wear of the inner ring 21.

[0076] (Second Embodiment) Next, a blower according to a second embodiment will be described. Figure 4 2 is a cross-sectional view showing the axial direction of the blower 2 of this embodiment. Figure 4 As shown, the blower 2 has the same structure as the blower 1 except that a part of the structure of the bearing device 280 is different from the structure of the bearing device 80 of the blower 1. Therefore, hereinafter, for the blower 2, only the points that are different from the blower 1 are described, and the other structures are marked with the same figure marks as the first embodiment and the description is omitted.

[0077] Figure 5 2 is a cross-sectional view schematically showing an enlarged state of the bearing device 280 when the impeller 56 is stationary. Figure 5 FIG. 2 shows a state of the bearing device 80 when the impeller 56 is stationary, when the blower 2 is arranged so that the protruding portion 10a of the shaft 10 faces upward in the vertical direction. Figure 5As shown, the bearing device 280 includes a second flange portion 228 and a second spring 240 .

[0078] The second flange portion 228 is supported by a portion of the shaft 10 that is lower (on the other side) than the inner ring 31 of the second ball bearing 30, and extends radially outward from the shaft 10. In the present embodiment, the second flange portion 228 is a washer that is embedded in a groove formed on the outer peripheral surface 10o of the shaft 10. It should be noted that the configuration of the second flange portion 228 is not limited thereto, and for example, it may also be a portion integrally formed with the shaft 10 in a flange shape.

[0079] The second spring 240 is located directly below the inner ring 31 of the second ball bearing 30 and is disposed between the upper surface of the second flange portion 228 and the lower surface 31d of the inner ring 31 of the second ball bearing 30. The shaft 10 passes through the inner side of the second spring 240. That is, the second spring 240 surrounds a portion of the outer peripheral surface 10o of the shaft 10.

[0080] When the impeller 56 of the blower 2 is stationary when the protruding portion 10a of the shaft 10 is arranged so as to face upward in the vertical direction, the bearing device 80 is similar to the bearing device 80. Figure 5 As shown by the dashed line in , due to the load F1 applied by the rotor 50, a preload is applied to the first ball bearing 20 in a state where the straight line connecting the contact points of the inner ring 21 and the outer ring 22 with the rotor 23 is inclined relative to the radial direction so as to be directed radially inward as it goes upward. When the impeller 56 is stationary, similarly to the bearing device 80, only the load F1 applied by the rotor 50 acts on the first ball bearing 20.

[0081] When the impeller 56 is stationary, the inner ring 31 of the second ball bearing 30 moves downward together with the shaft 10 due to the load F1 applied by the rotor 50. However, at a certain point in time when the inner ring 31 moves downward, the force applied to the inner ring 31 by the first spring 40 is balanced by the force applied to the inner ring 31 by the second spring 240 arranged between the inner ring 31 and the second flange portion 228, and the inner ring 31 is maintained at the position at that point in time. As in the case of the bearing device 80, the axial movement of the outer ring 32 of the second ball bearing 30 is restricted. Therefore, the inner ring 31 of the second ball bearing 30 is located on the lower side relative to the outer ring 32. Therefore, when the impeller 56 is stationary, the rotating body 33 of the second ball bearing 30 contacts the upper area of ​​the recess 31c of the inner ring 31 and the lower area of ​​the recess 32c of the outer ring 32. That is, when the impeller 56 is stationary, as Figure 5 As shown by the dashed line in , preload acts on the second ball bearing 30 while the straight line connecting the contact points between the inner ring 31 and the outer ring 32 and the rolling element 33 is inclined with respect to the radial direction so as to go radially outward as it goes downward.

[0082] Thus, in the bearing device 280, when the impeller 56 is stationary, the preload applied to the first ball bearing 20 and the second ball bearing 30 becomes the following parallel combination: the preload is applied in a state where the straight line connecting the contact points of the respective inner rings and outer rings with the rotating body is inclined relative to the radial direction in a manner toward the radial outside as it goes downward.

[0083] Next, the bearing device 280 when the impeller 56 rotates will be described.

[0084] Figure 6 2 is a cross-sectional view schematically showing the bearing device 280 when the impeller rotates in an enlarged manner. Figure 6 The diagram shows a state of the bearing device 280 when the impeller 56 rotates in a case where the blower 1 is arranged so that the protruding portion 10 a of the shaft 10 faces upward in the vertical direction.

[0085] like Figure 6 As shown by the middle arrow, when the impeller 56 rotates at a high speed, the thrust F2 is greater than the load F1 applied by the rotor 50, and as a result, the shaft 10 and the first flange portion 28 supported by the shaft 10 move upward due to the thrust F2. Moreover, as a result of the upward movement of the first flange portion 28, the inner ring 21 of the first ball bearing 20 is pushed from the lower side (the other side) toward the upper side (one side) by the first flange portion 28 that contacts the lower surface 21d of the inner ring 21 and moves upward. As in the first embodiment, the outer ring 22 of the first ball bearing 20 is fixed (bonded by an adhesive) to the sleeve 81. Therefore, the inner ring 21 is located on the upper side relative to the outer ring 22. Therefore, when the impeller 56 rotates at a high speed, the rotating body 23 of the first ball bearing 20 contacts the lower area of ​​the recess 21c of the inner ring 21 and the upper area of ​​the recess 22c of the outer ring 22. That is, when the impeller 56 rotates at a high speed, as shown in FIG. Figure 6 As shown by the dashed line in , preload acts on the first ball bearing 20 while the straight line connecting the contact points of the inner ring 21, the outer ring 22 and the rolling element 23 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0086] When the impeller 56 rotates at a high speed, the inner ring 31 of the second ball bearing 30 supported by the shaft 10 moves upward together with the shaft 10 due to the thrust F2. When the rotation speed of the impeller 56 increases and the thrust F2 increases, the inner ring 31 moves further upward. Moreover, at a point in time when the inner ring 31 moves upward to a certain extent, the force applied to the inner ring 31 by the first spring 40 is balanced with the force applied to the inner ring 31 by the second spring 240 assembled on the second flange portion 228 and the inner ring 31, and the inner ring 31 is maintained at the position at that point in time. The axial movement of the outer ring 32 of the second ball bearing 30 is restricted. Therefore, the inner ring 31 of the second ball bearing 30 is located on the upper side relative to the outer ring 32. Therefore, when the impeller 56 rotates at a high speed, the rotating body 33 of the second ball bearing 30 contacts the lower area of ​​the recess 31c of the inner ring 31 and the upper area of ​​the recess 32c of the outer ring 32. That is, when the impeller 56 rotates at a high speed, as shown in FIG. Figure 6 As shown by the dashed line in , preload acts on the second ball bearing 30 while the straight line connecting the contact points of the inner ring 31, the outer ring 32 and the rolling element 33 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0087] Thus, in the bearing device 280, when the impeller 56 rotates at high speed, the preload applied to the first ball bearing 20 and the second ball bearing 30 becomes the following parallel combination (i.e., a parallel combination in the opposite direction to that when stationary): the preload is applied while the straight line connecting the contact points of the respective inner rings and outer rings with the rotating body is inclined relative to the radial direction in a manner toward the radial outside as it moves upward.

[0088] It should be noted that, although not particularly limited, in the present embodiment, it is preferred that when the deflection amount of the first spring 40 and the second spring 240 changes the axial clearance amount of the first ball bearing 20 and / or the second ball bearing 30, the change in the load (applied force) applied by the first spring 40 and the second spring 240 is greater than the weight of the inner ring 31 of the second ball bearing 30.

[0089] As described above, the blower 2 of the present embodiment comprises: a shaft 10; a sleeve 81, which accommodates a portion of the shaft 10 (roughly except for the protrusion 10a) therein; an impeller 56, which is rotatably supported on one side of the shaft 10 in the axial direction, and generates an air flow from one side in the axial direction toward the other side in the axial direction by rotation; a first ball bearing 20, which includes: an inner ring 21, which is supported on a portion of the shaft 10 close to the impeller 56; and an outer ring 22, which is fixed to the inner circumferential surface 81i of the sleeve 81; a second ball bearing 30, whose inner ring 31 is supported on a portion of the shaft 10 that is farther away from the impeller 56 than the inner ring 21 of the first ball bearing 20; a first flange portion 28, which is supported on the shaft 10 between the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30, and extends radially outward from the shaft 10; and a first spring 40, which is arranged between the first flange portion 28 and the inner ring 31 of the second ball bearing 30. Furthermore, in the blower 2, the first flange portion 28 presses the inner ring 21 of the first ball bearing 20 from the other side toward one side when the impeller 56 rotates.

[0090] Therefore, according to the blower 2, the rotation speed of the impeller 56 can be increased and the impeller 56 can be smoothly started to rotate for the same reason as the blower 1. Moreover, since the blower 2 includes the gasket 29 as in the first embodiment, the noise generated when the impeller 56 rotates or the wear of the inner ring 21 is suppressed.

[0091] Furthermore, in the blower 2 , since the inner ring 31 of the second ball bearing 30 is supported in a state of being sandwiched from above and below by the first spring 40 and the second spring 240 , the inner ring 31 of the second ball bearing 30 has excellent shock absorption performance.

[0092] (Third Embodiment) Next, a blower according to a third embodiment will be described. Figure 7 2 is a cross-sectional view showing the axial direction of the blower 2 of this embodiment. Figure 7 As shown, the blower 3 has the same structure as the blower 1 except that a part of the structure of the bearing device 380 is different from the structure of the bearing device 80 of the blower 1. Therefore, hereinafter, only the points that are different from the blower 1 will be described for the blower 3, and the other structures are marked with the same reference numerals as the first embodiment and the description is omitted.

[0093] Figure 8 2 is a cross-sectional view schematically showing the state of the bearing device 380 when the impeller 56 is stationary. Figure 8 FIG. 3 shows a state of the bearing device 380 when the impeller 56 is stationary, when the blower 3 is arranged so that the protruding portion 10a of the shaft 10 faces upward in the vertical direction. Figure 8As shown, the bearing device 380 includes a second flange portion 328 and a third spring 340 .

[0094] The second flange portion 328 is supported by a portion of the shaft 10 that is lower (on the other side) than the inner ring 31 of the second ball bearing 30, and extends radially outward from the shaft 10. In the present embodiment, the second flange portion 328 is a washer that is embedded in a groove formed in the outer peripheral surface 10o of the shaft 10. In the present embodiment, when the impeller 56 is stationary, the second flange portion 328 contacts the lower surface 31d of the inner ring 31 of the second ball bearing 30, but it may not contact. In addition, the configuration of the second flange portion 328 is not limited to this, and for example, it may be a portion integrally formed with the shaft 10 in a flange shape.

[0095] The third spring 340 is arranged between the step portion 81P of the sleeve 81 and the outer ring 32 of the second ball bearing 30 in the axial direction. That is, the third spring 340 is arranged between the lower surface 81Pd of the step portion 81P of the sleeve 81 and the upper surface 32u of the outer ring 32 of the second ball bearing 30. In the present embodiment, the third spring 340 is composed of one spring, but may be composed of two or more spring pieces arranged at equal intervals in the circumferential direction.

[0096] It should be noted that the bearing device 380 is different from the bearing devices 80 and 280 and does not include the fixing portion 60 .

[0097] When the impeller 56 of the blower 3 is stationary when the protruding portion 10a of the shaft 10 is arranged so as to face upward in the vertical direction, the bearing device 80 is similar to the bearing device 80. Figure 8 As shown by the dashed line in , due to the load F1 applied by the rotor 50, a preload is applied to the first ball bearing 20 in a state where the straight line connecting the contact points of the inner ring 21 and the outer ring 22 with the rotor 23 is inclined relative to the radial direction so as to go downward toward the radially outer side. When the impeller 56 is stationary, similarly to the bearing device 80, only the load F1 applied by the rotor 50 acts on the first ball bearing 20.

[0098] When the impeller 56 is stationary, the inner ring 31 of the second ball bearing 30 supported by the shaft 10 moves downward together with the shaft 10 due to the load F1 applied by the rotor 50. On the other hand, the outer ring 32 of the second ball bearing 30 moves downward due to the biasing force of the third spring 340. Therefore, the inner ring 31 and the outer ring 32 of the second ball bearing 30 are arranged at substantially the same position in the axial direction. Therefore, when the impeller 56 is stationary, substantially no preload is applied to the second ball bearing 30.

[0099] In this way, in the bearing device 380, the following combination is formed: when the impeller 56 is stationary, the first ball bearing 20 is preloaded, and the second ball bearing 30 is not preloaded, while the straight line connecting the contact points of the inner ring and the outer ring with the rotating body is inclined relative to the radial direction in a manner toward the inner side of the radial direction as it goes upward.

[0100] Next, the bearing device 380 when the impeller 56 rotates will be described.

[0101] Fig. 9 2 is a cross-sectional view schematically showing the bearing device 380 when the impeller rotates in an enlarged manner. Fig. 9 The diagram shows a state of the bearing device 380 when the impeller 56 rotates in a case where the blower 3 is arranged so that the protruding portion 10 a of the shaft 10 faces upward in the vertical direction.

[0102] like Fig. 9 As shown by the middle arrow, when the impeller 56 rotates at a high speed, the thrust F2 is greater than the load F1 applied by the rotor 50, and as a result, the shaft 10 and the first flange portion 28 supported by the shaft 10 move upward due to the thrust F2. Moreover, as a result of the upward movement of the first flange portion 28, the inner ring 21 of the first ball bearing 20 is pushed from the lower side (the other side) toward the upper side (one side) by the first flange portion 28 that contacts the lower surface 21d of the inner ring 21 and moves upward. As in the first embodiment, the outer ring 22 of the first ball bearing 20 is fixed (bonded by an adhesive) to the sleeve 81. Therefore, the inner ring 21 is located on the upper side relative to the outer ring 22. Therefore, when the impeller 56 rotates at a high speed, the rotating body 23 of the first ball bearing 20 contacts the lower area of ​​the recess 21c of the inner ring 21 and the upper area of ​​the recess 22c of the outer ring 22. That is, when the impeller 56 rotates at a high speed, as shown in FIG. Fig. 9 As shown by the dashed line in , preload acts on the first ball bearing 20 while the straight line connecting the contact points of the inner ring 21, the outer ring 22 and the rolling element 23 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0103] When the impeller 56 rotates at a high speed, the second flange portion 328 moves upward together with the shaft 10 due to the thrust F2. As a result, the second flange portion 328 contacts the lower surface 31d of the inner ring 31 of the second ball bearing 30, and moves (pushes) the inner ring 31 from the lower side (the other side) to the upper side (one side). When the rotation speed of the impeller 56 increases and the thrust F2 increases, the inner ring 31 moves further upward through the second flange portion 328. At this time, the inner ring 31 is held in a position in contact with the second flange portion 328 by the urging force applied to the inner ring 31 by the first spring 40. On the other hand, the outer ring 32 of the second ball bearing 30 is pushed upward via the rotor 33 as the inner ring 31 moves upward, but the upward movement is restricted by the urging force of the third spring 340. Therefore, the inner ring 31 of the second ball bearing 30 is located relatively above the outer ring 32. Therefore, when the impeller 56 rotates at high speed, the rotor 33 of the second ball bearing 30 contacts the lower area of ​​the recess 31c of the inner ring 31 and the upper area of ​​the recess 32c of the outer ring 32. Fig. 9 As shown by the dashed line in , preload acts on the second ball bearing 30 while the straight line connecting the contact points of the inner ring 31, the outer ring 32 and the rolling element 33 is inclined relative to the radial direction so as to go radially outward as it goes upward.

[0104] Thus, in the bearing device 380, when the impeller 56 rotates at high speed, the preload applied to the first ball bearing 20 and the second ball bearing 30 becomes the following parallel combination: the preload is applied in a state where the straight line connecting the contact points of the respective inner rings and outer rings with the rotating body is inclined relative to the radial direction in a manner toward the radial outside as it goes upward.

[0105] It should be noted that, although not particularly limited, in the bearing device 380 of the present embodiment, the maximum value of the load (applied force) applied by the first spring 40 and the maximum value of the load (applied force) applied by the third spring 340 are respectively smaller than the load F1 applied by the rotor 50 when the blower 2 is arranged in a manner such that the protrusion 10a of the shaft 10 faces the upper side in the vertical direction. Here, as described above, the thrust F2 when the impeller 56 rotates at a high speed is greater than the load F1 applied by the rotor 50. That is, in the present embodiment, the load applied by the first spring 40 and the load applied by the third spring 340 are respectively smaller than the thrust F2 when rotating at a high speed. Therefore, in the bearing device 380, particularly when rotating at a high speed, the respective applied forces of the first spring 40 and the third spring 340 are suppressed from acting in a manner to overcome the thrust F2.

[0106] As described above, the blower 3 of the present embodiment comprises: a shaft 10; a sleeve 81, which accommodates a portion of the shaft 10 (roughly except for the protrusion 10a) therein; an impeller 56, which is rotatably supported on one side of the shaft 10 in the axial direction, and generates an air flow from one side in the axial direction toward the other side in the axial direction by rotation; a first ball bearing 20, which includes: an inner ring 21, which is supported on a portion of the shaft 10 close to the impeller 56; and an outer ring 22, which is fixed to the inner circumferential surface 81i of the sleeve 81; a second ball bearing 30, whose inner ring 31 is supported on a portion of the shaft 10 that is farther away from the impeller 56 than the inner ring 21 of the first ball bearing 20; a first flange portion 28, which is supported on the shaft 10 between the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30, and extends radially outward from the shaft 10; and a first spring 40, which is arranged between the first flange portion 28 and the inner ring 31 of the second ball bearing 30. Furthermore, in the blower 3 , the first flange portion 28 presses the inner ring 21 of the first ball bearing 20 from the other side toward one side when the impeller 56 rotates.

[0107] Therefore, according to the blower 3, the rotation speed of the impeller 56 can be increased and the impeller 56 can be smoothly started to rotate for the same reason as the blower 1. Moreover, since the blower 2 includes the gasket 29 as in the first embodiment, the noise generated when the impeller 56 rotates or the wear of the inner ring 21 is suppressed.

[0108] Furthermore, in the blower 3 , since the outer ring 32 of the second ball bearing 30 is supported via the third spring 340 , the outer ring 32 of the second ball bearing 30 has excellent shock absorption performance.

[0109] (Fourth Embodiment) Next, a blower according to a fourth embodiment will be described. Fig.10 It is a cross-sectional view in the axial direction showing the air-sending device 4 according to the present embodiment. Fig.11 When the impeller is stationary Fig.10 The bearing device 480 shown is enlarged and schematically shown in a cross-sectional view. Fig.10 and Fig.11 As shown, the blower 4 has the same structure as the blower 1 except that a part of the structure of the bearing device 480 is different from the structure of the bearing device 80 of the blower 1. Therefore, hereinafter, only the points that are different from the blower 1 will be described for the blower 4, and the other structures are marked with the same figure marks as the first embodiment and the description is omitted.

[0110] like Fig.10 and Fig.11As shown, the bearing device 480 of the blower 4 has a substantially similar structure to the bearing device 80 of the blower 1, but is different from the bearing device 80 of the blower 1 mainly in the following points: the sleeve 481 has a protruding portion 482; and the sleeve 81 of the bearing device 80 includes a step portion 81P, whereas the sleeve 481 of the bearing device 480 does not include a step portion like the step portion 81P, but includes a spacer 483 that is separate from the sleeve 481. These differences are described below.

[0111] like Fig.10 and Fig.11 As shown in FIG. 1 , a projection 482 protruding radially inward is formed on the inner circumference of the sleeve 481. In the axial direction, the projection 482 is formed at the upper end or near the upper end of the sleeve 481 and is formed integrally with other parts of the sleeve 481. In the radial direction, the inner circumferential surface 482i of the projection 482 is located on the inner side relative to other parts of the sleeve 481. In the radial direction, the inner circumferential surface 482i of the projection 482 may be located at the same position as the inner circumferential surface 22i of the outer ring 22 of the first ball bearing 20, or may be located on the inner side or on the outer side relative to the inner circumferential surface 22i. In the radial direction, a gap is formed between the inner circumferential surface 482i of the projection 482 and the surface 53i of the bushing 53 opposite to the inner circumferential surface 482i. The projection 482 may be formed in an annular shape (covering the entire circumference of the sleeve 481) or may be formed as a part of the circumferential direction of the sleeve 481. The upper surface 22u (one axial end of the first ball bearing 20) of the outer ring 22 of the first ball bearing 20 abuts against the lower surface (lower surface) of the extension portion 482. Therefore, the extension portion 482 restricts the outer ring 22 of the first ball bearing 20 from moving upward.

[0112] In the present embodiment, the inner peripheral surface 481 i of the sleeve 481 is formed to be flush with the inner peripheral surface 482 i of the extension portion 482 .

[0113] The bearing device 480 includes a spacer 483. The spacer 483 is a component different from the sleeve 481. The spacer 483 is supported so as not to move relative to the sleeve 481 in the axial direction. The spacer 483 may be pressed into the inner peripheral surface 482i of the sleeve 481, or may be bonded to the inner peripheral surface 482i. In this way, the spacer 483 is a component different from the sleeve 481, and thus, the first ball bearing 20 can be inserted into the sleeve 481 from the opening 481bo on the lower side of the sleeve 481, so that the first ball bearing 20 can be moved toward the upper end of the sleeve 481, and then, the spacer 483 can be inserted into the sleeve 481 from the opening 481bo, so that the spacer 483 can be moved toward the first ball bearing 20. In the axial direction, the spacer 483 is located between the first ball bearing 20 and the second ball bearing 30.

[0114] In the axial direction, the outer ring 22 of the first ball bearing 20 is held by the protruding portion 482 and the spacer 483, thereby limiting the movement of the outer ring 22 of the first ball bearing 20 in the axial direction. In this embodiment, unlike the first, second, and third embodiments, the outer ring 22 of the first ball bearing 20 is not fixed (for example, bonded using an adhesive) to the inner circumferential surface 482i of the sleeve 481, but is held by, for example, a clearance fit, an intermediate fit, or an interference fit and arranged on the inner circumference of the sleeve 481. However, the outer ring 22 of the first ball bearing 20 may be fixed to the inner circumferential surface 482i of the sleeve 481 in the same manner as in the first, second, and third embodiments.

[0115] Thus, in the blower 4 of the present embodiment, a protruding portion 482 protruding radially inward is provided on the inner periphery of the sleeve 481, and the end portion of one side of the first ball bearing 20 (the upper surface 22u of the outer ring 22 of the first ball bearing 20) abuts against the protruding portion 482, and the outer ring 22 of the first ball bearing 20 is arranged on the inner periphery of the sleeve 481. According to such a configuration, even if the outer ring 22 of the first ball bearing 20 is not fixed (for example, bonded) to the sleeve 481, the outer ring 22 of the first ball bearing 20 can be restricted from moving upward. In addition, in the present embodiment, a spacer 483 is further provided, so that even if the outer ring 22 of the first ball bearing 20 is not fixed (for example, bonded) to the sleeve 481, the axial movement of the outer ring 22 of the first ball bearing 20 can be restricted. In addition, except for these points, the blower 4 has the same configuration as the blower 1 of the first embodiment. Therefore, even when the impeller 56 rotates at a high speed, preload can be applied to both the first ball bearing 20 and the second ball bearing 30 without applying an excessive load, and the rotation speed of the impeller 56 can be increased.

[0116] Furthermore, such a protruding portion 482 and a spacer 483 can also be applied to the first embodiment, the second embodiment, and the third embodiment. In this case, the axial movement of the outer ring 22 of the first ball bearing 20 can be restricted (the position of the outer ring 22 in the axial direction can be maintained) without fixing the outer ring 22 of the first ball bearing 20 to the sleeve. In particular, when the protruding portion 482 and the spacer 483 are applied to the first embodiment and the second embodiment, the outer ring 22 of the first ball bearing 20 and the outer ring 32 of the second ball bearing 30 can be clamped in the axial direction by the protruding portion 482 and the fixing portion 60, thereby restricting the axial movement of the outer rings 22 and 32. In addition, when the protruding portion 482 and the spacer 483 are applied to the first embodiment and the second embodiment, the spacer 483 does not need to be supported (for example, fixed) so as not to move relative to the sleeve 481 in the axial direction. When the extension 482 and the spacer 483 are applied to the first embodiment and the second embodiment, the outer ring 22 of the first ball bearing 20, the outer ring 32 of the second ball bearing 30, and the spacer 483 can be clamped between the extension 482 and the fixing portion 60, so that the axial movement of the two outer rings 22, 32 and the spacer 483 can be restricted. In this way, when the inner ring 21 of the first ball bearing 20 and the inner ring 31 of the second ball bearing 30 are not fixed to the shaft 10, and the outer ring 22 of the first ball bearing 20 and the outer ring 32 of the second ball bearing 30 and the spacer 483 are not fixed to the sleeve 481, respectively, the assembly of the blower 4 becomes easy by omitting the fixing process such as bonding. In addition, the disassembly and repair of the blower 4 become easier.

[0117] In the above, the present invention has been described by taking the above-mentioned embodiment as an example, but the present invention is not limited thereto.

[0118] For example, in the above-mentioned embodiment, an example in which the gasket 29 is provided is described, but the gasket 29 may not be provided.

[0119] In the above embodiment, the step portion 81P is formed on the sleeve 81 , but the step portion 81P may not be formed. In this case, the outer peripheral surface of the outer ring 32 of the second ball bearing 30 may be bonded to the inner peripheral surface 81 i of the sleeve 81 .

[0120] In addition, those skilled in the art can make appropriate changes to the blower of the present invention based on the prior common knowledge. As long as the structure of the present invention is still possessed through such changes, it is naturally included in the scope of the present invention. Description of Reference Numerals

[0121] 1, 2, 3, 4: blower; 10: shaft; 20: first ball bearing; 21: inner ring; 22: outer ring; 28: first flange portion; 29: washer; 30: second ball bearing; 31: inner ring; 32: outer ring; 40: first spring; 50: rotor; 56: impeller; 60: fixing portion; 81, 481: sleeve; 81P: step portion; 228, 328: second flange portion; 240: second spring; 340: third spring; 482: extension portion.

Claims

1. A blower, comprising: axis; a sleeve, accommodating a portion of the shaft therein; an impeller rotatably supported on one side of the shaft in the axial direction, and generating an air flow from the one side in the axial direction toward the other side in the axial direction by rotating; A first ball bearing, comprising: an inner ring supported on the shaft at a portion close to the impeller; and an outer ring fixed to an inner circumferential surface of the sleeve; a second ball bearing, the inner ring of which is supported on a portion of the shaft that is farther from the impeller than the inner ring of the first ball bearing; A first flange portion supported on the shaft between the inner ring of the first ball bearing and the inner ring of the second ball bearing and extending from the axial direction and the radial direction perpendicular to the axial direction to the outer side; and a first spring disposed between the first flange portion and the inner ring of the second ball bearing, The first flange portion presses the inner ring of the first ball bearing from the other side toward the one side when the impeller rotates.

2. A blower, comprising: axis; a sleeve, accommodating a portion of the shaft therein; an impeller rotatably supported on one side of the shaft in the axial direction, and generating an air flow from the one side in the axial direction toward the other side in the axial direction by rotating; A first ball bearing comprising: An inner ring supported on the shaft at a portion close to the impeller; and an outer ring disposed on the inner periphery of the sleeve; a second ball bearing, the inner ring of which is supported on a portion of the shaft that is farther from the impeller than the inner ring of the first ball bearing; A first flange portion supported on the shaft between the inner ring of the first ball bearing and the inner ring of the second ball bearing and extending from the axial direction and the radial direction perpendicular to the axial direction to the outer side; and a first spring disposed between the first flange portion and the inner ring of the second ball bearing, A protruding portion protruding inward in the radial direction is provided on the inner periphery of the sleeve. The end portion of the first ball bearing on the one side abuts against the protruding portion, The first flange portion presses the inner ring of the first ball bearing from the other side toward the one side when the impeller rotates.

3. The blower according to claim 1 or 2, wherein: The impeller forms part of a rotor that rotates relative to the sleeve as the shaft rotates, A maximum value of a load applied by the first spring is smaller than a load applied by the rotor.

4. The blower according to claim 1 or 2, wherein: The outer ring of the second ball bearing is restricted from moving in the axial direction.

5. The blower according to claim 4, wherein: The blower further includes a fixing portion, which is fixed to the inner peripheral surface of the sleeve and extends inwardly in the radial direction. The sleeve includes a step portion protruding inward in the radial direction at a portion closer to the one side than the fixing portion. The outer ring of the second ball bearing is clamped by the step portion and the fixing portion so as to be restricted from moving in the axial direction.

6. The blower according to claim 5, wherein: The blower also has: A second flange portion supported on the shaft at a portion closer to the other side than the inner ring of the second ball bearing and extending from the shaft to the outside in the radial direction; and The second spring is arranged between the second flange portion and the inner ring of the second ball bearing.

7. The blower according to claim 6, wherein: The impeller forms part of a rotor that rotates relative to the sleeve as the shaft rotates, When the deflection amount of the first spring and the second spring changes by the axial clearance amount of the first ball bearing and / or the second ball bearing, the change amount of the load applied by the first spring and the second spring is greater than the weight of the inner ring of the second ball bearing.

8. The blower according to claim 1 or 2, wherein: The blower further includes a second flange portion, the second flange portion being supported on a portion of the shaft closer to the other side than the inner ring of the second ball bearing and extending from the axial direction to the outer side in the radial direction. The sleeve includes a step portion protruding inward in the radial direction at a portion between the outer ring of the first ball bearing and the outer ring of the second ball bearing in the axial direction. A third spring is arranged between the step portion and the outer ring of the second ball bearing in the axial direction, The second flange portion presses the inner ring of the second ball bearing from the other side toward the one side when the impeller rotates.

Images