An axial flow fan

Abstract

The utility model relates to a fan field, concretely relates to a axial flow fan, fan frame, inside radial support rib support stator subassembly has the medium pipe with the axle hole, bearing assembly includes the first bearing and second bearing of interval arrangement in the axle hole, and the outer ring of first bearing is with the axle hole axial location, the outer ring of second bearing can slip axially to the axle hole, mandrel, inner extension end stretches into the axle hole and passes through first bearing, second bearing, inner extension end is equipped with the first limit surface, and the end part is equipped with the pressure structure that can exert along the axial force, is located between first bearing and second bearing in the axle hole and has the first inner hole for mandrel to pass through. The utility model can solve the obvious deficiency of the existing axial flow fan in bearing pre -tightening adjustment, supporting structure stiffness optimization, key component connection reliability and maintainability, make the fan satisfy the use demand of high stability, long life, easy maintenance.

Description

Technical Field

[0001] This utility model relates to the field of fans, specifically to an axial flow fan. Background Technology

[0002] Axial flow fans, as core ventilation and heat dissipation equipment, are widely used in household appliances, industrial control cabinets, automotive electronics, military equipment, and other scenarios. Their operational stability, support structure reliability, and service life directly affect the working efficiency, operating noise, and maintenance costs of downstream equipment. In existing fans, the preload force is highly dependent on the accuracy of bolt tightening torque or shim thickness. However, factors such as the friction coefficient of the thread pair and the elastic deformation of the shims during bolt tightening can easily lead to a large deviation between the actual preload force and the design value. If the preload force is insufficient, assembly gaps cannot be completely eliminated, and vibration and noise are likely to occur during spindle operation, accelerating bearing wear. If the preload force is too large, it will cause a surge in internal contact stress in the bearing, leading to bearing overheating, lubrication failure, and severely shortening the bearing's service life. Furthermore, axial flow fans generate continuous vibration and temperature changes during operation. Rigid preload structures cannot adapt to the thermal expansion and contraction differences between the spindle and the housing caused by temperature changes, easily leading to preload loosening or further increase, resulting in unstable preload conditions and affecting the long-term operational reliability of the equipment. Utility Model Content

[0003] The purpose of this utility model is to address the shortcomings of existing technologies by providing an axial flow fan. This utility model aims to solve the defects of existing axial flow fans in terms of bearing preload adjustment, support structure rigidity optimization, key component connection reliability and maintainability, so that the fan can meet the requirements of high stability, long service life and easy maintenance.

[0004] The purpose of this utility model is achieved as follows: an axial flow fan, comprising:

[0005] A sector frame, internally supported by radial support ribs, the stator assembly having a central tube with a shaft hole;

[0006] The bearing assembly includes a first bearing and a second bearing spaced apart within the shaft hole, wherein the outer ring of the first bearing is axially limited to the shaft hole; and the outer ring of the second bearing is axially movable relative to the shaft hole.

[0007] The mandrel has an inner end that extends into a shaft hole and passes through a first bearing and a second bearing. The inner end is provided with a first limiting surface, and the end is provided with a clamping structure that can apply force along the axial direction. The clamping end of the clamping structure abuts against the first limiting surface and the end of the inner ring of the first bearing. The outer end of the mandrel is provided with an impeller.

[0008] A bushing, disposed within a shaft hole and located between a first bearing and a second bearing, has a first inner hole through which a mandrel passes;

[0009] A first gasket is arranged in the shaft hole and between the first bearing and the shaft sleeve, and has a second inner hole through which the mandrel passes;

[0010] A pre-tightening spring is loosely arranged on the mandrel, and a first end of the pre-tightening spring presses against the first gasket, and a second end of the pre-tightening spring presses against the first end of the shaft sleeve, and a second end of the shaft sleeve abuts against an outer ring of the second bearing.

[0011] The impeller is provided with a stepped hole, one end of the mandrel is fitted in a small hole section of the stepped hole, and the mandrel is provided with a second limiting shoulder which abuts against the small hole section of the stepped hole; a fastener passes through a positioning sleeve in the stepped hole and is connected with the end of the mandrel, the positioning sleeve is pressed against a large diameter section of the stepped hole, and the positioning sleeve is limited in the circumferential direction by the large diameter section of the stepped hole.

[0012] The outer periphery of the positioning sleeve is provided with a protrusion which extends into a recess in the hole wall of the large diameter section of the stepped hole.

[0013] The pressing structure comprises a locking bolt;

[0014] The end of the inner extending end of the mandrel is provided with a threaded hole, a rod portion of the locking bolt is threadedly connected with the threaded hole, and the extending direction of the rod portion is consistent with the axis of the mandrel;

[0015] The head portion of the locking bolt is larger in diameter than the hole diameter of the inner ring of the first bearing, the head end surface of the head portion directly abuts against the first limiting surface and the end portion of the inner ring of the first bearing, thereby constituting a pressing end of the pressing structure, and axial pressing limiting is realized through threaded cooperation.

[0016] The pressing structure comprises a locking bolt, a spring washer and a gasket;

[0017] The extending direction of the rod portion of the locking bolt is consistent with the axis of the mandrel, a spring washer and a gasket are sequentially arranged on the rod portion of the locking bolt, and the head portion of the locking bolt is located on the side of the spring washer away from the gasket;

[0018] The gasket abuts against the first limiting surface and the end portion of the inner ring of the first bearing, the spring washer is clamped between the head portion of the locking bolt and the gasket, the head portion, the spring washer and the gasket are sequentially pressed by the threaded connection of the locking bolt, and the gasket constitutes a pressing end of the pressing structure.

[0019] The first inner hole of the shaft sleeve is fitted with a pre-tightening spring, and a first end of the pre-tightening spring abuts against a flange in the first inner hole of the shaft sleeve.

[0020] The first bearing is a deep groove ball bearing or an angular contact ball bearing, and the second bearing is a deep groove ball bearing or an angular contact ball bearing.

[0021] The inner ring of the second bearing is in abutment with the shaft shoulder on the mandrel through a second shaft sleeve having a stepped hole therein, wherein the small-diameter hole of the stepped hole is in cooperation with the mandrel, the small-diameter hole of the stepped hole is in abutment at the opening end of the second bearing, the large-diameter hole of the stepped hole is in clearance cooperation with the mandrel, and the opening end of the large-diameter hole of the stepped hole is in abutment on the shaft shoulder.

[0022] The mounting seat is provided with a mounting hole, the second end of the middle tube is inserted into the mounting hole, the middle tube is provided with a first shaft shoulder, and a nut is threadedly connected with the internal thread of the second end, the first shaft shoulder and the nut are respectively in abutment at two ends of the mounting hole, and the mounting seat is clamped and fixed together.

[0023] The stator assembly comprises a mounting seat, the outer portion of the middle tube is provided with a Whitworth thread, the mounting seat is provided with a mounting hole, the mounting hole is in positive rotation connection with the Whitworth thread, a reverse rotation limiting nut is arranged on the Whitworth thread, and the reverse rotation limiting nut is in abutment at the opening end in the mounting hole, and a dust cover is arranged at the opening end out of the mounting hole.

[0024] By adopting the above scheme, the following beneficial effects are achieved: the pre-tightening spring sleeved on the mandrel continuously acts on the first gasket and the shaft sleeve by elastic pressure, and then indirectly transmits the elastic pressure to the outer ring of the second bearing, and the pre-tightening force is almost unchanged: the pre-tightening force attenuation and loosening caused by rigidity pre-tightening due to temperature change or vibration are avoided, and stress concentration of the bearing caused by excessive pre-tightening is also avoided. No matter whether the fan is in a start-stop cycle or long-term operation, the pre-tightening force is always maintained in the design range, so that stable cooperation between the bearing and the mandrel is ensured.

[0025] In the structure, the outer ring of the first bearing is axially limited, and the outer ring of the second bearing can slide relative to the shaft hole, and the assembly error and the use wear gap between the two bearings can be automatically compensated by the constant pressure of the pre-tightening spring: the inner / outer rings of the first bearing and the second bearing are uniformly stressed, and early wear, jamming or overheating failure of a single bearing due to overload, such as pre-tightening force concentration, is avoided. Compared with the structure without constant pressure pre-tightening, the service life of the bearing can be improved, and the replacement frequency of the core components of the fan can be reduced.

[0026] The constant pressure pre-tightening force is accurately transmitted to the bearing through the shaft sleeve and the gasket, the radial and axial gaps in the bearing can be eliminated, the coaxiality of the mandrel can be kept stable during high-speed operation, the mandrel can be prevented from shaking due to the gaps, and the radial runout of the outer extension end impeller can be controlled in the minimum range.

[0027] The traditional pre-tightening structure needs to repeatedly adjust the axial position of the bearing to control the pre-tightening force, and the assembly difficulty is high; the structure does not need to accurately calibrate the gap between the bearings by the elastic compensation characteristics of the pre-tightening spring: only the spring needs to be assembled according to the designed compression amount, and a stable pre-tightening force can be automatically formed, and the assembly efficiency is improved. At the same time, if the bearing appears a small amount of wear during long-term use, the spring can automatically compensate the gap and maintain the pre-tightening state, and frequent disassembly and maintenance are not needed, and the later operation and maintenance cost is reduced.

[0028] By using the utility model, the impeller and the mandrel are not prone to loosening due to vibration, and the cooperation of the bearing, the mandrel and the impeller is always in a stable state by the constant pressure pre-tightening mechanism, so that the mandrel deviation and bearing overheating caused by pre-tightening imbalance can be avoided even under complex working conditions such as fan start-stop impact, environmental temperature fluctuation or load change. Compared with the axial flow fan without constant pressure pre-tightening, the overall operation failure rate is reduced, the service life is prolonged, and it is especially suitable for continuous operation of industrial ventilation, household appliance heat dissipation and the like.

[0029] The utility model will be further described below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is the front view of the utility model;

[0031] Figure 2 It is the rear view of the utility model;

[0032] Figure 3 It is Figure 2 It is the middle A-A section view;

[0033] Figure 4 It is another connection structure diagram of the middle tube.

[0034] 100 is the fan frame, 110 is the radial support rib, 200 is the stator assembly, 300 is the middle tube, 304 is the Tang screw, 310 is the shaft hole, 320 is the first bearing, 330 is the second bearing, 340 is the mandrel, 341 is the first limiting surface, 342 is the second limiting shoulder, 344 is the second shaft shoulder, 400 is the pre-tightening structure, 410 is the locking bolt, 420 is the elastic pad, 430 is the gasket, 500 is the shaft sleeve, 511 is the flange, 520 is the second shaft sleeve, 600 is the first gasket, 700 is the pre-tightening spring, 800 is the impeller, 810 is the positioning sleeve, 820 is the fastener, 900 is the mounting seat, 910 is the nut, 930 is the limiting nut and 940 is the dust cover. DETAILED DESCRIPTION

[0035] The specific implementation scheme of the utility model will be described in detail with reference to the drawings.

[0036] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0037] In the description of the present application, it needs to be understood that the terms center, upper, lower, front, rear, left, right, vertical, horizontal, top, bottom, inner, outer and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the terms first, second, etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with first, second can be used to explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of multiple is two or more. It should be noted that in actual application, due to the limitation of equipment precision or installation error, absolute parallelism or perpendicularity effect is difficult to achieve. In the present application, the description of vertical, parallel or same direction is not an absolute limitation condition, but indicates that the vertical or parallel structure can be realized within the preset error range and achieve the corresponding preset effect, so that the technical effect of the limited features can be maximized, and the corresponding technical scheme is easy to implement and has high feasibility.

[0038] In the description of the present application, the description of the terms one embodiment, some embodiments, examples, specific examples, or some examples means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0039] Referring to Figures 1-4 An embodiment of an axial flow fan, comprising: a fan frame 100, an inner part supported by a radial support rib 110, a stator assembly 200, the stator assembly 200 having a middle tube 300 with an axial hole 310;

[0040] The bearing assembly comprises a first bearing 320 and a second bearing 330 arranged in the shaft hole 310, and the outer ring of the first bearing 320 is axially limited by the shaft hole 310; the outer ring of the second bearing 330 can axially slide relative to the shaft hole 310; a mandrel 340, the inner end of which extends into the shaft hole 310 and passes through the first bearing 320 and the second bearing 330, and the inner end is provided with a first limiting surface 341; an end portion is provided with a pressing structure 400 which can apply axial force; the pressing end of the pressing structure 400 abuts against the first limiting surface 341 and the inner ring end portion of the first bearing 320; the outer end of the mandrel 340 is provided with an impeller 800; a shaft sleeve 500 is arranged in the shaft hole 310 and located between the first bearing 320 and the second bearing 330, and has a first inner hole through which the mandrel 340 passes; a first washer 600 is arranged in the shaft hole 310 and located between the first bearing 320 and the shaft sleeve 500, and has a second inner hole through which the mandrel 340 passes; a pre-tightening spring 700 is arranged around the mandrel 340, and the first end of the pre-tightening spring 700 presses the first washer 600, and the second end of the pre-tightening spring 700 presses the first end of the shaft sleeve 500, and the second end of the shaft sleeve 500 abuts against the outer ring of the second bearing 330.

[0041] In some embodiments, the impeller 800 is provided with a stepped hole, one end of the mandrel 340 is fitted into a small hole section of the stepped hole, and the mandrel 340 is provided with a second limiting shoulder 342 which abuts against the small hole section of the stepped hole; a fastener 820 passes through a positioning sleeve 810 arranged in the stepped hole and is connected with the end portion of the mandrel 340, the positioning sleeve 810 is pressed against a large diameter section of the stepped hole, and the positioning sleeve 810 is limited in the circumferential direction by the large diameter section of the stepped hole. The setting of the positioning sleeve 810 can increase the area, so that the torque transmission of the mandrel 340 is more dispersed, and at the same time, the pressure of the fastener 820 can be dispersed to prevent the impeller from being crushed. Further, the positioning sleeve 810 can transmit torque through interference or key connection, etc. In this embodiment, the outer periphery of the positioning sleeve 810 is provided with a protrusion which extends into a recess on the hole wall of the large diameter section of the stepped hole, and the torque is transmitted through the shearing force of the protrusion. In further embodiments, the protrusion can be integrally formed with the positioning sleeve 810, which is convenient for assembly and has high shearing strength.

[0042] In some embodiments, the pressing structure 400 comprises a locking bolt 410; the inner end of the mandrel 340 is provided with a threaded hole, the rod portion of the locking bolt 410 is threadedly connected with the threaded hole, and the extending direction of the rod portion is consistent with the axis of the mandrel 340; the head portion of the locking bolt 410 has a diameter larger than the inner ring hole diameter of the first bearing 320, and the head end surface thereof directly abuts against the first limiting surface 341 and the inner ring end portion of the first bearing 320 to form the pressing end of the pressing structure 400, and the axial pressing limiting is realized through the threaded cooperation, so that the position of the inner ring of the first bearing 320 can be accurately limited.

[0043] In some embodiments, the compression structure 400 comprises a locking bolt 410, a spring washer 420 and a washer 430; the rod of the locking bolt 410 extends along the axis of the mandrel 340, the spring washer 420 and the washer 430 are sequentially sleeved on the rod of the locking bolt 410, and the head of the locking bolt 410 is located on the side of the spring washer 420 away from the washer 430; the washer 430 abuts against the first limiting surface 341 and the inner ring end of the first bearing 320, the spring washer 420 is clamped between the head of the locking bolt 410 and the washer 430, the head, the spring washer 420 and the washer 430 are sequentially compressed by the threaded connection of the locking bolt 410, and the washer 430 constitutes the compression end of the compression structure 400. Compared with the direct contact of the head of the locking bolt 410 with the inner ring of the bearing or the limiting surface, the washer 430 increases the contact area, converts the concentrated compression force of the bolt into uniformly distributed surface pressure, and prevents scratches; on the one hand, the spring washer 420 is elastically deformed under the action of the threaded pre-tightening force of the locking bolt 410, can continuously apply a reverse elastic pressure to the washer 430, offset the pre-tightening force attenuation caused by vibration, impact or thermal expansion and contraction during operation, and maintain stable axial compression force.

[0044] In some embodiments, the first inner hole of the shaft sleeve 500 is matched with a pre-tightening spring 700, and the first end of the pre-tightening spring 700 abuts against the flange 511 in the first inner hole of the shaft sleeve 500. By providing the flange 511, reliable support can be achieved, and at the same time, the mouth of the shaft sleeve 500 has a small wall thickness, which can adapt to the outer ring of a small corresponding bearing, such as the outer ring of the second bearing 330.

[0045] In some embodiments, the first bearing 320 is a deep groove ball bearing or an angular contact ball bearing, and the second bearing 330 is a deep groove ball bearing or an angular contact ball bearing.

[0046] In some embodiments, the mandrel 340 is provided with a second shaft shoulder 344 on the side close to the second bearing 330, the inner ring of the second bearing 330 abuts against the second shaft shoulder 344 on the mandrel 340 through a second shaft sleeve 520, the second shaft sleeve 520 has a stepped hole therein, the small-diameter hole of the stepped hole is matched with the mandrel 340, the small-diameter hole end of the stepped hole abuts against the inner ring of the second bearing 330, the large-diameter hole of the stepped hole is clearance-fitted with the mandrel 340, and the large-diameter hole end of the stepped hole abuts against the second shaft shoulder 344. With this structure, the arc chamfer and other structures on the mandrel 340 can be avoided, reliable contact, stability and transmission of axial force can be achieved.

[0047] In some embodiments, the stator assembly 200 includes a mounting seat 900 having a mounting hole into which the second end of the middle tube 300 is inserted, the middle tube 300 is provided with a first shaft shoulder, and a nut 910 is threadedly connected with the internal thread of the second end, the first shaft shoulder and the nut 910 abut the two ends of the mounting hole respectively and jointly clamp and fix the mounting seat 900, so that the impeller 800 can be clamped and fixed, the torque can be transmitted through friction, and assembly and maintenance are facilitated.

[0048] In some embodiments, the stator assembly 200 includes a mounting seat 900 having a mounting hole into which the second end of the middle tube 300 is inserted, the middle tube 300 is provided with a first shaft shoulder, and a nut 910 is threadedly connected with the internal thread of the second end, the first shaft shoulder and the nut 910 abut the two ends of the mounting hole respectively and jointly clamp and fix the mounting seat 900, so that the impeller 800 can be clamped and fixed, the torque can be transmitted through friction, and assembly and maintenance are facilitated.

[0049] By using the above scheme, the pre-tightening spring 700 is sleeved on the mandrel 340, and the elastic pressure continuously acts on the first gasket 600 and the shaft sleeve 500, and is then indirectly transmitted to the outer ring of the second bearing 330, so that the pre-tightening force is almost unchanged: the pre-tightening force caused by rigid pre-tightening due to thermal expansion and contraction or vibration of components caused by heating of the fan during operation is avoided, and stress concentration of the bearing caused by interference pre-tightening is also avoided. Whether the fan is in a start-stop cycle or long-term operation, the pre-tightening force is always maintained in the design range, so as to ensure the stable cooperation between the bearing and the mandrel 340.

[0050] In the structure, the outer ring of the first bearing 320 is axially limited, and the outer ring of the second bearing 330 can slide relative to the shaft hole 310, and the assembly error and the use wear gap between the two bearings can be automatically compensated by the constant pressure of the pre-tightening spring 700: the inner / outer rings of the first bearing 320 and the second bearing 330 are uniformly stressed, and early wear, jamming or overheating failure of a single bearing caused by overload such as pre-tightening force concentration is avoided, the service life of the bearing can be improved, and the replacement frequency of the core components of the fan is reduced.

[0051] The constant pressure pre-tightening force is accurately transmitted to the bearing through the shaft sleeve 500 and the gasket 430, the radial and axial gaps in the bearing can be eliminated, the coaxial stability of the mandrel 340 can be maintained during high-speed operation, the mandrel 340 can be prevented from shaking due to the gap, and the radial runout of the overhanging end impeller 800 can be controlled in the minimum range.

[0052] The traditional pre-tightening structure needs to repeatedly adjust the axial position of the bearing to control the pre-tightening force, and the assembly is difficult; the utility model discloses the elastic compensation characteristics of the pre-tightening spring 700, and the bearing gap does not need to be accurately calibrated: only the spring needs to be assembled according to the designed compression amount, and stable pre-tightening force can be automatically formed, and the assembly efficiency is improved. At the same time, if the bearing appears slight wear in long-term use, the spring can automatically compensate the gap and maintain the pre-tightening state, frequent disassembly and maintenance are not needed, and the later operation and maintenance cost is reduced.

[0053] The constant-pressure pre-tightening mechanism makes the cooperation of the bearing, the mandrel 340 and the impeller 800 always in a stable state: even in the complex working conditions of fan start-stop impact, environmental temperature fluctuation or load change such as air duct resistance fluctuation, the mandrel 340 deviation and bearing overheating caused by pre-tightening imbalance can be avoided. Compared with the axial flow fan without constant-pressure pre-tightening, the overall operation failure rate is reduced, the service life is prolonged, and the utility model is especially suitable for continuous operation of industrial ventilation, household appliance heat dissipation and other scenes.

[0054] The above only describes the preferred embodiments of the utility model, and is not used to limit the utility model, and obviously, those skilled in the art can make various modifications and changes to the utility model without departing from the spirit and scope of the utility model. In this way, if these modifications and changes of the utility model belong to the scope of the utility model claims and equivalent technologies, then the utility model also intends to include these modifications and changes.

Claims

1. An axial flow fan characterised in that, The application relates to an axial flow fan, which comprises the following components: a fan frame (100) internally supporting a stator assembly (200) through radial supporting ribs (110), wherein the stator assembly (200) has a middle tube (300) with an axial hole (310); a bearing assembly comprising a first bearing (320) and a second bearing (330) arranged in the axial hole (310) in a spaced manner, wherein the outer ring of the first bearing (320) is axially limited by the axial hole (310), and the outer ring of the second bearing (330) can axially slide relative to the axial hole (310); a mandrel (340) with an inner end extending into the axial hole (310) and penetrating through the first bearing (320) and the second bearing (330), wherein the inner end is provided with a first limiting surface (341), and the end is provided with a pressing structure (400) capable of applying axial force, the pressing end of the pressing structure (400) abuts against the first limiting surface (341) and the inner end of the outer ring of the first bearing (320), and the outer end of the mandrel (340) is provided with an impeller (800); a shaft sleeve (500) arranged in the axial hole (310) and located between the first bearing (320) and the second bearing (330), and having a first inner hole for the mandrel (340) to penetrate through; a first gasket (600) arranged in the axial hole (310) and located between the first bearing (320) and the shaft sleeve (500), and having a second inner hole for the mandrel (340) to penetrate through; a pre-tightening spring (700) arranged on the mandrel (340) and pressing the first gasket (600) at a first end and pressing the shaft sleeve (500) at a second end, and the second end of the shaft sleeve (500) abuts against the outer ring of the second bearing (330).

2. An axial fan as claimed in claim 1, characterized in that The impeller (800) is provided with a stepped hole, one end of the mandrel (340) is matched with a small hole section of the stepped hole, and the mandrel (340) is provided with a second limiting shoulder (342) abutting against the small hole section of the stepped hole; a fastener (820) penetrates through a positioning sleeve (810) in the stepped hole and is connected with the end of the mandrel (340), the positioning sleeve (810) is pressed in a large-diameter section of the stepped hole, and the positioning sleeve (810) is limited in the circumferential direction by the large-diameter section of the stepped hole.

3. An axial fan as claimed in claim 2, characterised in that The outer periphery of the positioning sleeve (810) is provided with a protrusion, and the protrusion extends into a recess on the hole wall of the large-diameter section of the stepped hole.

4. An axial fan as claimed in claim 1, characterized in that The pressing structure (400) comprises a locking bolt (410); The end of the inner end of the mandrel (340) is provided with a threaded hole, the rod part of the locking bolt (410) is threadedly connected with the threaded hole, and the extending direction of the rod part is consistent with the axis of the mandrel (340); The head diameter of the locking bolt (410) is larger than the hole diameter of the inner ring of the first bearing (320), the head end surface of the locking bolt (410) directly abuts against the first limiting surface (341) and the inner end of the inner ring of the first bearing (320), and the head end surface of the locking bolt (410) constitutes the pressing end of the pressing structure (400).

5. The axial flow fan according to claim 1, wherein the pressing structure (400) comprises a locking bolt (410), a spring washer (420) and a gasket (430). ​ The rod of the locking bolt (410) extends along the axis of the mandrel (340), and the rod is sequentially sleeved with a spring washer (420) and a washer (430), and the head of the locking bolt (410) is located on the side of the spring washer (420) away from the washer (430); The washer (430) abuts against the first limiting surface (341) and the inner ring end of the first bearing (320), the spring washer (420) is clamped between the head of the locking bolt (410) and the washer (430), the head, the spring washer (420) and the washer (430) are sequentially compressed by the threaded connection of the locking bolt (410), and the washer (430) constitutes the compression end of the compression structure (400).

6. An axial fan as claimed in claim 1, characterized in that The first inner hole of the shaft sleeve (500) is matched with a pre-tightening spring (700), and the first end of the pre-tightening spring (700) abuts against the flange (511) in the first inner hole of the shaft sleeve (500).

7. An axial fan as claimed in claim 1, characterized in that The first bearing (320) is a deep groove ball bearing or an angular contact ball bearing, and the second bearing (330) is a deep groove ball bearing or an angular contact ball bearing.

8. An axial fan as claimed in claim 1, characterized in that The inner ring of the second bearing (330) abuts against the second shaft shoulder (344) of the mandrel (340) through the second shaft sleeve (520), the second shaft sleeve (520) has a stepped hole, the small-diameter hole of the stepped hole is matched with the mandrel (340), the small-diameter hole of the stepped hole abuts against the inner ring of the second bearing (330), the large-diameter hole of the stepped hole is in clearance fit with the mandrel (340), and the large-diameter hole of the stepped hole abuts against the second shaft shoulder (344).

9. An axial fan as claimed in claim 1, characterized in that The stator assembly (200) comprises a mounting seat (900) provided with a mounting hole, the second end of the middle pipe (300) is inserted into the mounting hole, the middle pipe (300) is provided with a first shaft shoulder, and a nut (910) is threadedly connected with the internal thread of the second end, the first shaft shoulder and the nut (910) abut against the two ends of the mounting hole respectively, and the mounting seat (900) is clamped and fixed.

10. An axial fan as claimed in claim 1, characterized in that The stator assembly (200) comprises a mounting seat (900), the middle pipe (300) is provided with a Whitworth thread (304), the mounting seat (900) is provided with a mounting hole, the mounting hole is connected with the Whitworth thread (304) in a normal rotation mode, a reverse rotation limiting nut (930) is arranged on the Whitworth thread (304) and abuts against the inner end of the mounting hole, and the outer end of the mounting hole is provided with a dust cover (940).

Images