Assembling method of ultrathin fan capable of preventing fan blades from falling off

Abstract

The invention discloses an assembling method of an ultrathin fan capable of preventing fan blades from falling off. The assembling method comprises the steps that a fan frame, a sleeve, an oil bearing, a shaft core, an oil seal cover and an anti-falling piece are prepared; an anti-falling piece is installed on an assembling structure at the bottom end of a shaft core of the rotor assembly, and the anti-falling piece at least comprises a limiting part exposed out of the shaft core; the sleeve is arranged at the opening in the lower end of the fan frame, and the oil bearing is fixed in the through cavity from bottom to top; the rotor assembly is inserted into a bearing hole of the oil-retaining bearing from top to bottom until the limiting part of the anti-falling piece is located below the oil-retaining bearing, and the upper end of the shaft core is connected with the fan blades; the lower end of the through cavity of the sleeve is covered with the oil seal cover in a sealed mode, so that assembling is completed; when the shaft core is subjected to abnormal upward axial force, the limiting part of the anti-falling piece abuts against the lower end face of the oil bearing, so that axial limiting of the shaft core is achieved, and the fan blades are prevented from falling off.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ultra-thin fan technology, in particular to an assembly method of an ultra-thin fan capable of preventing fan blades from falling off. BACKGROUND

[0002] Thin fans are widely used in the field of electronic equipment heat dissipation due to their compact structure and small thickness. The reliability of the fan lies in the stable operation of the fan blade assembly, and preventing the shaft core and the fan blade from falling off from the bearing during high-speed rotation or accidental pulling is the key.

[0003] Currently, the industry cannot add a retaining ring assembly to the ultra-thin fan from the bottom of the shaft core upwards. There are problems in implementation because the internal space of the fan bearing with a height of 3.4 mm or less is insufficient to install a retaining ring, resulting in no retaining ring installation during assembly, which causes the fan blades to easily fall off or become loose in the axial direction when subjected to vertical impact, causing the fan to fail. Interference with the upper cover or other objects causes the fan blades to be damaged or produce abnormal noise. In addition, the traditional assembly method of using a pressure ring to press from top to bottom in the prior art can easily cause the lubricating oil to be squeezed out during the process of installing the shaft core into the bearing, making it difficult to control the standard oil amount, and adding a anti-falling structure can easily cause the fan blades to be stuck, the fan to produce abnormal noise, the production yield to be low, and the production cost to be high. Therefore, the ultra-thin fan series basically has no anti-falling structure. Furthermore, the prior art relies entirely on magnetic bias pull to attract and fix. In the case of small size of the ultra-thin fan parts, the magnetic attraction force generated is limited in application scenarios. However, this type of magnetic bias pull structure is not stable in the axial direction of the fan frame and cooperation, and is easy to come off, causing loss. Therefore, the existing ultra-thin bearing structure should be improved to improve the stability of the fan blade assembly, the application range of scenarios, safety, and reduce production costs.

[0004] Therefore, it is necessary to research a new technical solution to solve the above problems. SUMMARY

[0005] In view of the above, the present application aims at the defects of the prior art, and the main purpose is to provide an assembling method of an ultra-thin fan capable of preventing the fan blades from falling off. The assembling structure is recessed at the bottom end surface of the shaft core, the anti-falling piece is directly installed in the assembling structure and can move with the shaft core. When the limiting part abuts against the lower end surface of the oil-impregnated bearing, the anti-falling piece and the oil-impregnated bearing jointly limit the shaft core. In this way, the axial displacement of the shaft core is limited to prevent the fan blades from falling off. In the normal working state, the shaft core can float between the oil-impregnated bearing and the anti-falling piece. When the shaft core is subjected to an abnormal upward axial force, the limiting part of the anti-falling piece moves upward with the shaft core and quickly abuts against the lower end surface of the oil-impregnated bearing to limit the shaft core mechanically, thereby preventing the fan blades from falling off and improving the safety and reliability of the product. In addition, the oil-impregnated bearing is designed to be installed upside down, and the oil seal cover is used to seal the lower end of the through cavity, thereby forming double protection. In this way, on the one hand, the inverted structure enables the lubricating oil of the oil-impregnated bearing to concentrate in the bearing under the action of gravity, thereby avoiding the problem of lubricating oil loss from the lower end opening due to centrifugal force in the traditional vertical installation structure, which is conducive to prolonging the service life of the bearing and reducing the operating noise.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: An assembling method of an ultra-thin fan capable of preventing the fan blades from falling off, characterized in that it comprises the following steps: S1, component preparation: prepare a fan frame, a sleeve, an oil-impregnated bearing, a rotor assembly, an oil seal cover and an anti-falling piece. The bottom end of the shaft core is provided with an assembling structure. The lower end of the fan frame has an opening, the sleeve has a through cavity arranged vertically, and the anti-falling piece at least includes a limiting part exposed outside the shaft core. S2, installation of the sleeve and the fan frame: the sleeve is arranged at the opening at the lower end of the fan frame, and the oil-impregnated bearing is fixed in the through cavity from bottom to top. S3, assembly of the rotor assembly: the rotor assembly is inserted into the bearing hole of the oil-impregnated bearing from top to bottom, and then the anti-falling piece is installed on the shaft core of the rotor assembly until the limiting part of the anti-falling piece is located below the oil-impregnated bearing. S4, oil injection: lubricating oil is injected between the oil-impregnated bearing and the shaft core. S5, packaging: the oil seal cover is sealed at the lower end of the through cavity of the sleeve to complete the assembly. After the assembly is completed, the limiting part of the anti-falling piece is arranged opposite to the lower end surface of the oil-impregnated bearing, and the anti-falling piece can move with the shaft core. Under the action of the magnetic bias force of the fan blades, the shaft core has a downward movement tendency, so that the limiting part of the anti-falling piece keeps in contact or a slight gap state with the inner side of the oil seal cover. When the shaft core is subjected to an abnormal upward axial force, the limiting part of the anti-falling piece will abut against the lower end surface of the oil-impregnated bearing to limit the axial displacement of the shaft core, thereby preventing the fan blades from falling off.

[0007] As a preferred solution, in S3, after the rotor assembly is inserted into the oil- containing bearing, an axial movement gap is formed between the upper end surface of the limiting part and the lower end surface of the oil-containing bearing. When the shaft core moves upward beyond the axial movement gap, the upper end surface of the limiting part abuts against the lower end surface of the oil-containing bearing to limit the movement. The axial movement gap provides necessary axial floating space for the shaft core to adapt to slight deformation, thermal expansion and contraction, or magnetic force changes during operation, ensuring smooth operation and avoiding friction and noise caused by rigid contact. In addition, when the shaft core is subjected to abnormal axial force, the gap serves as a safe displacement buffer zone. Once the displacement exceeds this range, the limiting part of the anti-falling piece immediately forms a rigid mechanical abutment with the oil-containing bearing, achieving absolute reliable limiting while ensuring flexible operation and providing the highest safety protection against falling off.

[0008] As a preferred solution, before the oil seal cover is sealed in S5, a gasket is placed on the upper end surface of the oil seal cover or the lower end surface of the oil-containing bearing, so that the lower end surface of the oil-containing bearing at least partially abuts on the gasket. An active space is formed between the inside of the gasket and the limiting part of the anti-falling piece. By placing the gasket between the lower end surface of the oil-containing bearing and the oil seal cover, the pre-tightening force or axial gap of the bearing can be adjusted and optimized to improve the operating state of the bearing. In addition, the active space formed between the inside of the gasket and the outside of the anti-falling structure provides sufficient radial clearance for the anti-falling structure to move with the shaft core, effectively preventing unnecessary friction or interference with surrounding stationary components during movement, ensuring smooth operation.

[0009] As a preferred solution, before the lower end is sealed in S5, a wear-resistant sheet is placed in the recessed mounting position inside the oil seal cover. After assembly, the lower end of the limiting part of the anti-falling piece can optionally abut on the wear-resistant sheet. The design of the wear-resistant sheet reduces the wear rate of the lower end surface of the limiting part during long-term operation or under axial force, prolonging the service life of the shaft core and the oil seal cover, and avoiding abnormal noise caused by direct metal friction.

[0010] As a preferred solution, in S3, the anti-falling piece is subjected to low-temperature freezing treatment to shrink its size, and then it is aligned and pressed into the assembly structure of the shaft core. After the temperature of the anti-falling piece returns to normal, it forms an interference fit with the assembly structure to achieve connection strength and reliability. The interference fit formed by low-temperature shrinkage, pressing in, and then expanding to normal temperature can withstand the huge centrifugal force and long-term vibration at high speed, completely avoiding the risk of thread loosening or snap ring shifting, and improving the service life and safety of the fan.

[0011] As a preferred solution, the diameter of the limiting part is greater than the diameter of the bearing hole of the oil-containing bearing, so that no matter how much upward pulling force the shaft core receives, the limiting part cannot pass through the bearing hole, thereby forming a lock.

[0012] As a preferred solution, the fan frame is further provided with a stator assembly, which is press-fitted to the outside of the sleeve.

[0013] As a preferred solution, in S3, the anti-falling piece is detachably mounted on the assembly structure of the shaft core; the assembly structure can be a mounting groove vertically extending along the anti-falling piece; or the assembly structure is a clamping groove, and the anti-falling piece is a clamping ring clamped into the clamping groove; or the assembly structure is a threaded groove, and the anti-falling piece is a nut screwed onto the threaded groove. The detachable design allows the damaged anti-falling piece or shaft core to be conveniently replaced during fan maintenance or renovation without scrapping the entire rotor assembly.

[0014] The present application has obvious advantages and beneficial effects compared with the prior art. Specifically, from the above technical solution, The main is that the assembly structure is recessed at the bottom end surface of the shaft core, the anti-falling piece is directly installed in the assembly structure and can move with the shaft core, when the limiting part abuts on the lower end surface of the oil-containing bearing, the anti-falling piece and the oil-containing bearing jointly limit the shaft core, thus realizing the constraint of the axial displacement of the shaft core to clasp the fan blade from falling off; and in the normal working state, the shaft core can float between the preset oil-containing bearing and the anti-falling piece, when the shaft core is subjected to an abnormal upward axial tension, the limiting part of the anti-falling piece moves upward with the shaft core and quickly forms a rigid abutment with the lower end surface of the oil-containing bearing to mechanically limit the fan blade from falling off, thereby improving the safety and reliability of the product in use. Secondly, the oil-containing bearing is designed to be inverted from bottom to top, cooperating with the oil seal cover to seal the lower end of the through cavity, forming double protection, in this way, on the one hand, the inverted structure makes the lubricating oil of the oil-containing bearing concentrate in the bearing under the action of gravity, avoiding the problem of lubricating oil loss from the lower end opening due to centrifugal force in the traditional vertical structure, which is conducive to prolonging the service life of the bearing and reducing the operating noise; on the other hand, the oil seal cover realizes the full sealing of the through cavity, which can effectively block the external dust and water vapor from entering the bearing and shaft core cooperation area, thereby avoiding the aggravation of wear. In addition, the anti-falling piece is directly installed in the assembly structure of the shaft core, without occupying additional axial space, cooperating with the compact design of the sleeve and the oil seal cover, the overall thickness of the fan can be controlled to adapt to the ultra-thin scene requirements.

[0015] To make the structure characteristics and effects of the present application clearer, the present application will be described in detail below with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a perspective view of an embodiment of the present application; Figure 2 is a sectional view of an embodiment of the present application; Figure 3 is an exploded view of an embodiment of the present application; Figure 4 is Figure 2 is a local enlarged view of A in figure 1.

[0017] Brief Description of the Drawings 1, frame; 11, opening; 2, fan blade; 3, sleeve; 31, through cavity; 4, oil bearing; 41, bearing hole; 5, shaft core; 51, assembly space; 6, oil seal cover; 61, gasket; 62, movable space; 63, mounting position; 64, wear-resistant sheet; 611, through hole; 612, cavity; 7, anti-falling piece; 71, limiting part; 72, vertical mounting part; 73, axial movable gap; 8, stator assembly; 81, stator shot package; 82, magnet. DETAILED DESCRIPTION

[0018] Please refer to Figures 1 to 4 , which shows the specific structure of the embodiment of the application.

[0019] In the description of the application, it should be noted that the terms "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the application.

[0020] An assembling method of an ultra-thin fan capable of preventing fan blades from falling off, comprising the following steps: S1, component preparation: preparing a frame 1, a fan blade 2, a sleeve 3, an oil bearing 4, a shaft core 5, an oil seal cover 6 and an anti-falling piece 7; wherein the bottom end of the shaft core 5 is provided with an assembly structure; wherein the lower end of the frame 1 has an opening 11, the sleeve 3 has a through cavity 31 arranged vertically, and the anti-falling piece 7 at least includes a limiting part 71 exposed outside the shaft core 5; S2, sleeve 3 and frame 1 installation: arranging the sleeve 3 at the opening 11 of the lower end of the frame 1, and fixing the oil bearing 4 from bottom to top in the through cavity 31; S3, rotor assembly assembly: the shaft core 5 assembly of the rotor assembly is inserted into the bearing hole 41 of the oil bearing 4 from top to bottom, then the anti-drop piece 7 is installed on the shaft core 5 of the rotor assembly, until the limiting part 71 of the anti-drop piece 7 is below the oil bearing 4, and the upper end of the shaft core 5 is connected with the fan blade 2; wherein the anti-drop piece 7 is installed on the assembly structure 51 at the bottom end of the shaft core 5, preferably in S3, the anti-drop piece 7 is detachably installed on the assembly structure 51 of the shaft core 5; the assembly structure 51 can be a mounting groove 51 arranged vertically along the anti-drop piece 7; or; the assembly structure is a clamping groove, and the anti-drop piece 7 is a clamping ring clamped in the clamping groove; or; the assembly structure is a threaded groove, and the anti-drop piece 7 is a nut screwed on the threaded groove; the detachable design allows the damaged anti-drop piece 7 or shaft core 5 to be conveniently replaced during fan maintenance or renovation without scrapping the entire rotor assembly. Wherein the fan blade and the shaft core of the rotor assembly are connected together; S4, oil injection: injecting lubricating oil between the oil bearing 4 and the shaft core 5; S5, packaging: the oil seal cover 6 is sealed at the lower end of the through cavity 31 of the sleeve 3 to complete the assembly; wherein after the assembly is completed, the limiting part 71 of the anti-drop piece 7 is arranged opposite to the lower end surface of the oil bearing 4 and the anti-drop piece 7 can move with the shaft core 5; under the action of the magnetic biasing force of the fan blade 2, the shaft core 5 has a downward movement trend, so that the limiting part 71 of the anti-drop piece 7 keeps in contact or a micro-gap state with the inner side of the oil seal cover 6; when the shaft core 5 is subjected to an abnormal upward axial force, the limiting part 71 of the anti-drop piece 7 will abut against the lower end surface of the oil bearing 4 to realize the axial limiting of the shaft core 5, preventing the fan blade 2 from falling off. Preferably, the gasket 61 has a through hole 611 arranged vertically upward and downward, and the through hole 611 is vertically arranged upward and downward opposite to the mounting position 63 to form a cavity 612, and the lower end of the oil bearing 4 is at least partially located in the cavity 612.

[0021] Preferably, in S3, after the rotor assembly is inserted into the oil bearing 4, an axial movement gap 73 is formed between the upper end surface of the limiting part 71 and the lower end surface of the oil bearing 4, when the shaft core 5 moves upward beyond the axial movement gap 73, the upper end surface of the limiting part 71 abuts against the lower end surface of the oil bearing 4 for limiting, the axial movement gap 73 provides necessary axial floating space for the shaft core 5, so that it can adapt to slight deformation, thermal expansion and contraction or magnetic force change in operation, ensure smooth operation, avoid friction and noise caused by rigid contact, secondly, when the shaft core 5 is subjected to an abnormal axial force, the gap constitutes a safe displacement buffer zone, once the displacement exceeds this range, the limiting part 71 of the anti-drop piece 7 immediately forms a rigid mechanical abutment with the oil bearing 4, realizing absolutely reliable limiting, while ensuring flexible operation, providing the highest anti-falling safety guarantee.

[0022] Preferably, before the step S5 of covering, a gasket 61 is placed on the upper end face of the oil cover 6 or the lower end face of the oil- containing bearing 4, so that the lower end face of the oil- containing bearing 4 at least partially abuts on the gasket 61; an active space 62 is formed between the inside of the gasket 61 and the limiting portion 71 of the anti -falling piece 7, and the gasket 61 is arranged between the lower end face of the oil- containing bearing 4 and the oil cover 6, so as to adjust and optimize the pre-tightening force or axial clearance of the bearing and improve the running state of the bearing. In addition, the active space 62 formed between the inside of the gasket 61 and the outside of the anti -falling structure provides sufficient radial clearance for the anti -falling structure to move with the shaft core 5, effectively preventing unnecessary friction or interference with the surrounding stationary parts during movement, and ensuring smooth operation.

[0023] Preferably, before the step S5 of covering the lower end, a wear-resistant sheet 64 is placed in the mounting position 63 recessed in the oil cover 6; after assembly, the lower end of the limiting portion 71 of the anti -falling piece 7 can selectively abut on the wear-resistant sheet 64, and the design of the wear-resistant sheet 64 reduces the wear rate of the lower end face of the limiting portion 71 during long-term operation or under axial force, which not only prolongs the service life of the shaft core 5 and the oil cover 6, but also avoids abnormal noise caused by direct metal friction.

[0024] Preferably, in the step S3, the anti -falling piece 7 is subjected to low-temperature freezing treatment to shrink its size, and then is aligned and pressed into the assembly structure of the shaft core 5; after the temperature of the anti -falling piece 7 returns to normal temperature, the anti -falling piece 7 and the assembly structure form an interference fit to achieve connection strength and reliability. The interference fit formed by pressing into the assembly structure after low-temperature shrinkage and returning to normal temperature can withstand the huge centrifugal force under high speed and long-term vibration, completely avoiding the risk of thread loosening or snap ring shifting, and improving the service life and safety of the fan.

[0025] Preferably, the anti -falling piece 7 further comprises a vertical mounting portion 72, and the limiting portion 71 is arranged extending from the lower end of the vertical connecting portion; the anti -falling piece 7 is mounted in the installation groove 51 through the vertical mounting portion 72.

[0026] Preferably, the diameter of the limiting portion 71 is greater than the diameter of the bearing hole 41 of the oil- containing bearing 4, so that no matter how large the upward pulling force on the shaft core 5 is, the limiting portion 71 cannot pass through the bearing hole 41, thereby forming a lock.

[0027] Preferably, the fan frame 1 further comprises a stator assembly 8, which is press-fitted on the outside of the sleeve 3. The stator assembly 8 is arranged outside the sleeve 3, wherein the stator assembly 8 at least comprises a stator shot 81, a motor coil and a magnet 82; the stator shot 81 is sleeved on the outside of the sleeve 3; the motor coil is sleeved on the stator shot 81; and the magnet 82 is located at the outer periphery of the stator shot 81.

[0028] In this embodiment, when the fan is normally running, the shaft core 5 drives the fan blade 2 to rotate at high speed under electromagnetic drive, at this time, the shaft core 5 mainly bears the radial rotating load, due to manufacturing tolerance, thermal expansion or slight unbalanced force (magnetic bias pull) of the magnetic circuit, the shaft core 5 needs a small axial freedom to adapt to these changes, to ensure smooth operation and low noise, in this state, the anti-dropping piece moves synchronously with the shaft core 5, but does not contact the upper oil-containing bearing 44, the shaft core 5 and the anti-dropping piece 7 operate smoothly in a space guided by the bearing hole 41 of the oil-containing bearing 4 and limited by the upper and lower boundaries of the axial movable gap 73; When the fan is subjected to an abnormal axial force directed outward of the fan frame 1 (for example, severe vibration or collision during transportation), at this time, the shaft core 5 will displace upward with the anti-dropping piece 7 at the bottom end, once the displacement exceeds the preset range of the axial movable gap 73, the limiting portion 71 of the anti-dropping piece 7 will immediately make rigid mechanical abutment with the lower end surface of the oil-containing bearing 4 (or the lower surface of the gasket 61), since the oil-containing bearing 4 is firmly fixed in the sleeve 3 and the fan frame 1, this abutment forms a mechanical stop, at this time, the abnormal axial force is effectively absorbed and blocked through the path of the shaft core 5, the anti-dropping piece 7, the oil-containing bearing 4, the sleeve 3, and the fan frame 1, thereby completely preventing the shaft core 5 from further axial disengagement, ensuring that the fan blade 2 will not fall off.

[0029] The assembly process of this embodiment is described in detail as follows: First step: prepare the fan frame 1, fan blade 2, sleeve 3, oil-containing bearing 4, rotor assembly, oil seal cover 6 and anti-dropping piece 7 necessary parts, confirm that the bottom end of the shaft core 5 of the rotor assembly has been processed with an assembly structure 51 (such as a clamping groove, a threaded or interference fit section or a mounting groove) for installing the anti-dropping piece 7; confirm that the lower end of the fan frame 1 is provided with an opening 11, the sleeve 3 has a through cavity 31, and the anti-dropping piece 7 is designed with at least one limiting portion 71 that can be exposed outside the shaft core 5 after installation; Second step: position and install the sleeve 3 to the opening 11 at the lower end of the fan frame 1, ensure stable installation, press or install the oil-containing bearing 4 into the through cavity 31 of the sleeve 3 from the lower opening 11, and fix it in place; Third step: Carefully insert the rotor assembly (including shaft core 5) from the lower direction into the bearing hole 41 of the installed oil-impregnated bearing 4; install the anti-extraction piece 7 to the assembly structure 51 at the bottom end of the shaft core 5, first freeze the anti-extraction piece 7 at low temperature to make it slightly shrink in size, then align and press it into the assembly structure 51 of the shaft core 5, and after it returns to normal temperature, it forms a firm interference fit with the shaft core 5; after installation, the limiting portion 71 of the anti-extraction piece 7 must be completely exposed outside the shaft core 5; then push the rotor assembly upwards or adjust the position of the anti-extraction piece 7 until the limiting portion 71 of the anti-extraction piece 7 moves up to below the oil-impregnated bearing 4, at this time, a certain axial movement gap 73 should be reserved between the upper end face of the limiting portion 71 and the lower end face of the oil-impregnated bearing 4, and then install and fix the fan blades 2 to the upper end of the shaft core 5 to complete the connection of the rotor part and the fan blades 2; it should be noted that the diameter of the limiting portion 71 of the anti-extraction piece 7 should be greater than the inner diameter of the bearing hole 41 of the oil-impregnated bearing 4 to ensure that it can effectively limit the axial movement; Fourth step: Inject an appropriate amount of lubricating oil into the friction pair between the oil-impregnated bearing 4 and the shaft core 5 from the side hole or the upper direction of the sleeve 3 to ensure smooth operation; Fifth step: Optionally place a gasket 61 on the inner side of the upper end face of the oil seal cover 6 or in advance on the lower end face of the oil-impregnated bearing 4, which is used for adjustment or buffering, and the inner hole thereof needs to ensure that it provides sufficient movement space 62 for the limiting portion 71 of the anti-extraction piece 7; secondly, a wear-resistant sheet 64 can also be placed in the installation recess on the inner side of the oil seal cover 6, which is used to contact the lower end of the limiting portion 71 of the anti-extraction piece 7 during fan operation to reduce wear, and finally align and cover the oil seal cover 6 (with the gasket 61 or wear-resistant sheet 64 placed) at the lower end opening 11 of the through cavity 31 of the sleeve 3, and press or fix it to complete the overall sealing; it should be noted that the limiting portion 71 of the anti-extraction piece 7 is arranged opposite to the lower end face of the oil-impregnated bearing 4 and can rotate freely with the shaft core 5 and move axially within a certain range, so that when the fan blades 2 are subjected to the axial pulling force of the magnetic field, the rotor assembly has a downward movement tendency, and the lower end of the limiting portion 71 of the anti-extraction piece 7 keeps in contact or only has a slight gap with the inner side of the oil seal cover 6 (or the wear-resistant sheet 64); When the shaft core 5 is subjected to an abnormal upward axial force, the limiting portion 71 of the anti-extraction piece 7 can immediately move up and abut against the lower end face of the oil-impregnated bearing 4 (or the gasket 61), thereby preventing the shaft core 5 from further moving upward and achieving protection against the fan blades 2 from falling off.

[0030] The design of the present application focuses on: it is mainly through the recessed assembly structure at the bottom end surface of the shaft core, the anti-falling piece is directly installed in the assembly structure and can move with the shaft core, when the limiting part abuts on the lower end surface of the oil-containing bearing, the anti-falling piece and the oil-containing bearing jointly limit the shaft core, in this way, the axial displacement of the shaft core is constrained to prevent the fan blade from falling off; and in the normal working state, the shaft core can float between the preset oil-containing bearing and the anti-falling piece, when the shaft core is subjected to abnormal upward axial tension, the limiting part of the anti-falling piece moves upward with the shaft core and quickly forms a rigid abutment with the lower end surface of the oil-containing bearing, mechanical limiting is performed, the fan blade is prevented from falling off, and the use safety and reliability of the product are improved; Secondly, the oil-containing bearing is designed to be inverted from bottom to top, cooperating with the oil seal cover to seal the lower end of the through cavity, forming double protection, in this way, on the one hand, the inverted structure makes the lubricating oil of the oil-containing bearing concentrate in the bearing under the action of gravity, avoiding the problem of lubricating oil loss from the lower end opening due to centrifugal force in the traditional vertical structure, which is beneficial to prolong the service life of the bearing and reduce the operating noise; on the other hand, the oil seal cover realizes the full sealing of the through cavity, which can effectively block the external dust and water vapor from entering the bearing and shaft core cooperation area, avoiding aggravating wear; In addition, the anti-falling piece is directly installed in the assembly structure of the shaft core, without occupying additional axial space, cooperating with the compact design of the sleeve and the oil seal cover, the overall thickness of the fan can be controlled to adapt to the ultra-thin scene requirements.

[0031] The above is only a preferred embodiment of the present application, and does not limit the technical scope of the present application, so any slight modification, equivalent change and modification of the above embodiment according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A method for assembling an ultra-thin fan to prevent blade detachment, characterized in that, Includes the following steps: S1. Component preparation: Prepare a fan frame, sleeve, oil-impregnated bearing, rotor assembly, oil seal cover, and anti-detachment component; wherein, the bottom end of the shaft core is provided with an assembly structure; wherein, the lower end of the fan frame has an opening, and the sleeve has a through cavity that runs vertically through the shaft core; the anti-detachment component includes at least a limiting part that protrudes outside the shaft core. S2. Sleeve and fan frame installation: Place the sleeve at the opening at the lower end of the fan frame, and fix the oil-impregnated bearing in the through cavity from bottom to top; S3. Rotor assembly assembly: Insert the rotor assembly into the bearing hole of the oil-impregnated bearing from top to bottom, and then install the anti-disengagement component on the shaft core of the rotor assembly until the limiting part of the anti-disengagement component is located below the oil-impregnated bearing. S4. Lubrication: Inject lubricating oil between the oil-impregnated bearing and the shaft. S5. Packaging: The oil seal cover is placed over the lower end of the through cavity of the sleeve to complete the assembly. After assembly, the limiting part of the anti-detachment component is positioned opposite to the lower end face of the oil-impregnated bearing, and the anti-detachment component can move with the shaft core. Under the action of magnetic bias force on the fan blade, the shaft core has a downward movement tendency, so that the limiting part of the anti-detachment component maintains contact or a slight gap with the inner side of the oil seal cover. When the shaft core is subjected to an abnormal upward axial force, the limiting part of the anti-detachment component will abut against the lower end face of the oil-impregnated bearing to achieve axial limiting of the shaft core and prevent the fan blade from falling off.

2. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: In S3, after the rotor assembly is inserted into the oil-impregnated bearing, an axial movement gap is formed between the upper end face of the limiting part and the lower end face of the oil-impregnated bearing. When the shaft moves upward beyond the axial movement gap, the upper end face of the limiting part abuts against the lower end face of the oil-impregnated bearing for limiting.

3. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: Prior to the S5 encapsulation, a gasket is placed on the upper end face of the oil seal cap or the lower end face of the oil-impregnated bearing, such that the lower end face of the oil-impregnated bearing at least partially abuts against the gasket; a movable space is formed between the interior of the gasket and the limiting portion of the anti-disengagement component.

4. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: Before the lower end of S5 is sealed, a wear-resistant sheet is placed in the recessed mounting position inside the oil seal cover; after assembly, the lower end of the limiting part of the anti-detachment component can selectively abut against the wear-resistant sheet.

5. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: In S3, the anti-detachment component is subjected to low-temperature freezing treatment to shrink its size, and then it is aligned and pressed into the assembly structure of the shaft core. After its temperature returns to normal, the anti-detachment component and the assembly structure form an interference fit.

6. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 4, characterized in that: The diameter of the limiting part is larger than the diameter of the bearing bore of the oil-impregnated bearing.

7. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: The sector frame is also provided with a stator assembly, which is press-fitted onto the outside of the sleeve.

8. The assembly method of the ultra-thin fan for preventing blade detachment according to claim 1, characterized in that: In S3, the anti-detachment component is detachably installed on the assembly structure of the shaft core; the assembly structure can be a mounting groove extending vertically along the anti-detachment component; or; the assembly structure is a snap-fit ​​groove, and the anti-detachment component is a snap ring that snaps into the snap-fit ​​groove; or; the assembly structure is a threaded groove, and the anti-detachment component is a nut screwed onto the threaded groove.

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