Assembly structure between dynamic balance shaft and impeller
By introducing a combined structure of positioning conical shaft section and conical sleeve between the dynamic balance shaft and the impeller, the problem of difficulty in assembly and disassembly between the impeller and the dynamic balance shaft is solved, efficient assembly and disassembly is achieved, and part damage is reduced, ensuring good coaxiality.
Patent Information
- Application Number
- CN202423121140.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-12-18
AI Technical Summary
In the prior art, the assembly structure of the impeller and the dynamic balance shaft has problems such as difficulty in assembly and disassembly and easy to damage. Especially when maintaining a relatively good coaxial degree, the cooperation between the impeller and the dynamic balance shaft is very tight, resulting in low assembly and disassembly efficiency and easy to damage parts.
The combined structure of the positioning conical shaft section and the conical sleeve is adopted, and the initial centering is achieved through the coordination of the positioning conical shaft section and the impeller hub hole. The spiral lift of the conical sleeve and the lock nut is used to lock it at the other end of the impeller, avoiding close cooperation and simplifying the assembly and disassembly process.
It realizes efficient assembly and disassembly of the impeller and the dynamic balance shaft, reduces part damage, improves assembly and disassembly efficiency, and maintains good coaxiality.
Smart Images
Figure CN223241689U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to an assembly structure for an impeller and a dynamic balance shaft of a centrifugal fan. Background Art
[0002] The full name of a centrifugal fan is a centrifugal fan. Its main components include an impeller, a casing, a coupling, and a shaft. The impeller is mounted on the shaft and is the main functional component for generating wind pressure and transmitting energy. The casing houses the impeller and is used to introduce and exhaust gas, while converting part of the kinetic energy of the gas into pressure energy. The coupling is used to connect the shaft to the motor, which drives the shaft to rotate, thereby driving the impeller to rotate. Due to the relatively large size of the impeller and the relatively high speed of centrifugal fans, the rotor, including the impeller and shaft, has relatively high dynamic balancing requirements. Otherwise, the rotor will vibrate due to imbalance, which will not only increase noise but also increase wear on the bearings supporting the shaft.
[0003] Therefore, the assembly between the impeller and the shaft often requires that the impeller and the shaft maintain relatively good coaxiality. The prerequisite is that centrifugal fans must undergo assembly vibration testing before leaving the factory. Before assembly, the rotating impeller needs to be dynamically balanced. Only when the imbalance is within the allowable range can the next assembly work be carried out. The dynamic balance is often based on the dynamic balance test. The shaft or impeller is adjusted according to the dynamic balance test results. It is often not appropriate to adjust it after assembly.
[0004] Dynamic balance needs to be tested on a dynamic balance test device. At this time, the impeller 1 of the centrifugal fan needs to be installed on the dynamic balance shaft 3 of the dynamic balance test device. Figures 1-3 , the impeller 1 is now visible on the dynamic balance shaft 3 Figure 2 and Figure 3 In the figure, the dynamic balancing shaft 3 is a stepped shaft. The shaft section for mounting the impeller 1 is the shaft head 33 shown in the figure. The shaft section to the left of the shaft head 33 is the shaft body 31. A shoulder 32 is provided between the shaft body 31 and the shaft head 33 to position the hub sleeve 11 of the impeller 1 at this end. The shaft section of the dynamic balancing shaft 3 that fits the other end of the hub sleeve 11 is a threaded shaft section 36. After the impeller 1 is properly assembled on the dynamic balancing shaft 3, a round nut 35 is used in conjunction with a locking washer 34 to lock the impeller 1 to the dynamic balancing shaft 3.
[0005] Since the measured parts on the dynamic balancing machine need to maintain relatively good coaxiality with the dynamic balancing shaft 3, the same is true for the impeller 1. Figure 1The problem with the known assembly structure of the dynamic balancing shaft 3 and the impeller shown is that, in order to maintain relatively good coaxiality between the impeller 1 on the dynamic balancing shaft 3 and the dynamic balancing shaft 3, the fit between the impeller 1 and the dynamic balancing shaft 3 is a small clearance fit, and the fit clearance of the small clearance fit is generally 0.049 mm. The hub sleeve 11 of the impeller 1 is very tightly combined with the dynamic balancing shaft 3, resulting in great difficulty in assembling and disassembling the impeller 1 on the dynamic balancing shaft 3. It is often necessary to use special tools or a hammer to knock the impeller 1 off the dynamic balancing shaft 3, which is not only inefficient but also very easy to damage or damage the hub hole of the dynamic balancing shaft 3 and the hub sleeve 11. Utility Model Content
[0006] The purpose of the utility model is to provide an assembly structure between a dynamic balancing shaft and an impeller, which is relatively easy to assemble and disassemble, thereby having relatively high assembling and disassembling efficiency and is not prone to damaging the dynamic balancing shaft and the impeller.
[0007] According to an embodiment of the present invention, a structure for assembling a dynamic balancing shaft and an impeller is provided. The dynamic balancing shaft has a shaft head for mounting the impeller, and a positioning tapered shaft section is connected to one end of the shaft head, and a threaded shaft section is connected to the other end of the shaft head.
[0008] Correspondingly, one end of the impeller is positioned at the positioning cone shaft section;
[0009] A tapered sleeve is provided which fits over the threaded shaft section and partially intervenes in the impeller hub hole to position the impeller at the other end;
[0010] A locking nut is provided to cooperate with the threaded shaft section to lock the tapered sleeve at an end of the tapered sleeve away from the impeller.
[0011] In the above assembly structure, optionally, the locking nut is provided with a backup nut, a rotation-stop washer or a set screw;
[0012] When a set screw is adapted, a pair of set screws are adapted, and two corresponding set screw holes opened on the locking nut are symmetrical about the axis of the locking nut.
[0013] Optionally, the positioning tapered shaft section and the tapered sleeve have the same taper.
[0014] Optionally, the taper of the positioning tapered shaft section is 1:1.2~1:2.
[0015] Optionally, the hub hole of the impeller has a chamfer or a radius.
[0016] Optionally, the fitting clearance between the hub hole of the impeller and the shaft head is 0.5 mm to 1.5 mm.
[0017] Optionally, the height of the step formed by the large circle of the threaded shaft segment relative to the shaft head with a relatively larger diameter is 3-5 mm.
[0018] Optionally, the tapered sleeve and the locking nut are an integrated structure or the gap between the tapered sleeve and the threaded shaft section is 0.05 mm to 0.2 mm.
[0019] Optionally, the locking nut is a round nut.
[0020] Optionally, one end of the tapered sleeve that cooperates with the locking nut has a flange or a pair of ear plates symmetrically arranged with each other;
[0021] When a flange is used, two screw holes symmetrical to each other are opened on the flange;
[0022] When ear plates are used, screw holes are provided on the ear plates.
[0023] In an embodiment of the present invention, the assembly structure between a dynamic balancing shaft and an impeller is provided. The structures used to achieve good coaxiality between the dynamic balancing shaft and the impeller include a positioning tapered shaft section and a tapered sleeve. The positioning tapered shaft section is located at one end of the shaft head that mates with the impeller. The dynamic balancing shaft is provided with a threaded shaft section at the other end of the shaft head. The tapered sleeve is fitted over the threaded shaft section. Furthermore, the positioning tapered shaft section necessarily partially intersects the impeller hub bore. Its tapered shape ensures alignment between the impeller and the dynamic balancing shaft at this end. At the other end of the impeller, the tapered sleeve is partially pressed into the hub bore by a locking nut using the screw lift force, thereby locking the impeller from the second end. The outer surface of the tapered sleeve ensures alignment of the impeller at this end. This allows for a relatively large clearance between the impeller and the dynamic balancing shaft, eliminating the need for a tight fit (interference fit or transition fit) to achieve good coaxiality, thereby facilitating assembly and disassembly of the impeller. For the tapered sleeve, since it is only used for positioning and locking, its axial length is relatively small. Even if it fits relatively tightly with the large diameter of the threaded shaft section, it is easy to remove because the joint surface is relatively small. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The figure is a schematic diagram of the assembly structure of a known impeller and a dynamic balancing shaft.
[0025] Figure 2 for Figure 1 Enlarged view of part I.
[0026] Figure 3 for Figure 1 Enlarged view of Part II.
[0027] Figure 4 Schematic diagram of the assembly structure between the dynamic balancing shaft and the impeller in one embodiment.
[0028] Figure 5 for Figure 4 Enlarged view of Part III.
[0029] Figure 6 for Figure 4 Enlarged view of part IV.
[0030] In the figure: 1. Impeller, 2. Support wheel, 3. Dynamic balance shaft.
[0031] 11. Hub sleeve.
[0032] 31. Shaft body, 32. Shaft shoulder, 33. Shaft head, 34. Lock washer, 35. Round nut, 36. Threaded shaft section, 37. Positioning tapered shaft section, 38. Tapered sleeve. DETAILED DESCRIPTION
[0033] Figure 4 According to an embodiment of the present invention, an assembly structure between a dynamic balancing shaft 3 and an impeller 1 is provided. The impeller 1 is fitted onto the dynamic balancing shaft 3 in a sleeved manner. The shaft section of the dynamic balancing shaft 3 used to cooperate with the impeller 1 is the shaft head 33. The traditional positioning method depends on the stepped shaft feature of the dynamic balancing shaft 3, and a positioning shoulder is provided at one end of the shaft head 33, such as Figure 2 The shoulder 32 is shown in FIG.
[0034] It can be seen that whether it is Figure 1 A known assembly structure shown, or Figure 4 In an assembly structure based on an embodiment of the present invention, the dynamic balancing shaft 3 itself provides positioning for one end of the impeller 1. For the convenience of description, this end is referred to as the first end, and the other end used for positioning the impeller 1 is referred to as the second end.
[0035] It should also be noted that Figure 1 and Figure 4 In the structure shown, a round nut 35 is used to position and lock the second end of the impeller 1. The major diameter of the threaded shaft segment 36 used to cooperate with the round nut 35 is less than or equal to the diameter of the shaft head 33. In the embodiment of the present utility model, the major diameter of the threaded shaft segment 36 is smaller than the bearing 33, and is used to adapt to the tapered sleeve 38 and ensure that the tapered sleeve 38 can partially intervene in the hub hole of the impeller 1.
[0036] In addition, both the positioning tapered shaft section 37 and the tapered sleeve 38 use tapered surfaces to achieve positioning. Obviously, the end of the tapered surface facing the impeller 1 is the small end, and the other end is the large end.
[0037] For the impeller 1, both ends of its hub hole usually have chamfers, and the parts where the two conical surfaces are positioned are preferably parts other than the chamfers.
[0038] A keyway is formed on the shaft head 33 , and the dynamic balancing shaft 3 is circumferentially connected to the impeller 1 by a key connection through the keyway.
[0039] The length of the shaft head 33 is less than the length of the hub hole of the impeller 1, so that the hub sleeve can partially fit the threaded shaft section 36. Figure 1 The known assembly structure shown is still Figure 4 The assembly structures shown in the embodiments of the present invention all adopt this configuration, that is, the length of the hub hole is greater than the length of the shaft head 33, which will not be described in detail here.
[0040] The portion of the impeller 1 having the hub sleeve is also called a mounting seat or a mounting plate, which is common knowledge in the art and will not be described in detail here.
[0041] As can be seen from the foregoing description, the assembly structure of the embodiment of the present invention also utilizes a stepped shaft for the dynamic balancing shaft 3. Compared to the conventional shoulder 32 used to position the first end of the impeller 1, the dynamic balancing shaft 3 of the embodiment of the present invention utilizes a positioning tapered shaft section 37 at the first end to replace the shoulder 32. The impeller 1 is positioned at the first end by mating the first tapered surface of the positioning tapered shaft section 37 with the first end of the hub hole of the impeller 1. The mating of the first tapered surface with the hub hole facilitates ensuring the coaxiality between the first end of the impeller 1 and the dynamic balancing shaft 3.
[0042] Then, the tapered sleeve 38 is inserted from the second end of the dynamic balancing shaft 3, and the second tapered surface of the tapered sleeve 38 is partially inserted into the hub hole, and then the tapered sleeve 38 is pressed against the second end of the impeller 1 by means of the spiral lift of the locking nut and the threaded shaft section 36.
[0043] At this time, the coaxiality of the impeller 1 and the dynamic balancing shaft 3 at the second end depends on the fitting accuracy between the tapered sleeve 38 and the threaded shaft segment 36. Since the tapered sleeve 38 realizes positioning and clamping, it does not need to be too long. Therefore, even if the tapered sleeve 38 and the threaded shaft segment 36 fit relatively tightly, it is relatively easy to install and remove.
[0044] At the same time, due to the relatively good matching accuracy between the positioning tapered shaft section 37 and the hub hole, even if the matching accuracy between the tapered sleeve 38 and the dynamic balancing shaft 3 is relatively low, the coaxiality between the impeller 1 and the dynamic balancing shaft 3 is relatively easy to ensure.
[0045] In order to ensure the reliability of the locking between the locking nut and the threaded shaft section 36, the locking nut is provided with a backup nut, a stop washer 34 or a set screw. Among them, the setting of the backup nut is relatively simple as a whole and has little effect on the rotational inertia of the assembly formed between the impeller 1 and the dynamic balancing shaft 3.
[0046] As for the anti-rotation washer 34, it is a traditional and commonly used method, which is relatively simple to implement.
[0047] Regarding the use of the set screw, it is necessary to open a set screw hole on the locking nut. The set screw is commonly known as a top screw. The locking nut can be further locked on the threaded shaft section 36 through the set screw hole.
[0048] In order to reduce the influence on the dynamic balance, when the locking nut is further locked by a set screw, the two corresponding set screw holes are symmetrically arranged about the axis of the locking nut.
[0049] Furthermore, in order to reduce the impact on the dynamic balance of the assembly, the positioning tapered shaft section 36 and the tapered sleeve 38 have the same taper.
[0050] The taper of the positioning tapered shaft section 36 is 1:1.2 to 1:2. Under the condition of satisfying good positioning accuracy, for example, the axial movement of the round nut 35 is relatively small.
[0051] In order to facilitate assembly, the hub hole of the impeller 1 has a chamfer or a radius.
[0052] In view of the fact that two conical surfaces are used to realize the positioning of the impeller 1 on the dynamic balancing shaft 3, the requirements for the fitting clearance between the impeller 1 and the dynamic balancing shaft 3 are relatively low, that is, the coaxiality is no longer guaranteed by relying on the cylindrical surfaces of the two fitting together. Under this condition, the main consideration is the issue of assembly and disassembly. Therefore, the fitting clearance between the hub hole of the impeller 1 and the shaft head 33 is 0.5mm~1.5mm.
[0053] exist Figure 6 In the illustrated structure, the hub hole diameter of the hub sleeve 11 is slightly larger than the major diameter of the threaded shaft segment 36, thereby forming a step to achieve relatively reliable positioning. Accordingly, the height of the step formed by the major circle of the threaded shaft segment 36 relative to the shaft head 33 is 3~5mm, which is conducive to the intervention of the tapered sleeve 38.
[0054] At the same time Figure 6 As shown, the length of the hub sleeve 11 is greater than the length of the shaft head 33, and the longer portion is recorded as a first length, so that the length of the fitting section of the tapered sleeve 38 is shorter than the first length.
[0055] Furthermore, the tapered sleeve 38 and the locking nut are integrally formed. Under these conditions, the tapered sleeve 38 maintains relatively good coaxiality with the threaded shaft section 36, and thus with the shaft head 33. If the tapered sleeve 38 and the locking nut are separate structures, in order to ensure that the impeller 1 maintains good coaxiality with the dynamic balancing shaft 3 after being clamped, the gap between the tapered sleeve 38 and the threaded shaft section 36 should be kept relatively small, preferably between 0.05 mm and 0.2 mm.
[0056] Regarding the influence on the moment of inertia of the impeller 1 after being clamped on the dynamic balancing shaft 3 , the locking nut is preferably a round nut 35 .
[0057] Considering that the impeller 1 is clamped on the dynamic balancing shaft 3 by means of two conical surfaces, for example, the tapered sleeve 38 is relatively tightly engaged with the hub hole. Under this condition, the end of the tapered sleeve 38 that cooperates with the locking nut has a flange or a pair of ear plates symmetrically arranged with each other.
[0058] Accordingly, when a flange is used, two mutually symmetrical screw holes are opened on the flange;
[0059] When ear plates are used, corresponding screw holes are opened on the ear plates.
[0060] Screws can be used with the help of the screw holes. After the test is completed, first remove, for example, the round nut 35, and then install the screw on the screw hole so that the screw is held against the end face of the impeller 1. Then, the screw is further rotated, and the generated spiral lift can pull out, for example, the conical sleeve 38.
Claims
1. An assembly structure between a dynamic balancing shaft and an impeller, characterized in that: The dynamic balancing shaft has a shaft head for installing the impeller, and a positioning tapered shaft section is connected to one end of the shaft head, and a threaded shaft section is connected to the other end of the shaft head; Correspondingly, one end of the impeller is positioned at the positioning cone shaft section; A tapered sleeve is provided which fits over the threaded shaft section and partially intervenes in the impeller hub hole to position the impeller at the other end; A locking nut is provided to cooperate with the threaded shaft section to lock the tapered sleeve at an end of the tapered sleeve away from the impeller.
2. The assembly structure according to claim 1, characterized in that: The locking nut is provided with a backup nut, a rotation-stop washer or a set screw; When a set screw is adapted, a pair of set screws are adapted, and two corresponding set screw holes opened on the locking nut are symmetrical about the axis of the locking nut.
3. The assembly structure according to claim 1, characterized in that: The positioning tapered shaft section and the tapered sleeve have the same taper.
4. The assembly structure according to claim 3, characterized in that: The taper of the positioning tapered shaft section is 1:1.2~1:
2.
5. The assembly structure according to claim 4, characterized in that: The hub hole of the impeller has a chamfer or a radius.
6. The assembly structure according to claim 1, characterized in that: The fitting clearance between the hub hole of the impeller and the shaft head is 0.5mm~1.5mm.
7. The assembly structure according to claim 1 or 6, characterized in that: The height of the step formed by the large circle of the threaded shaft section relative to the relatively large diameter shaft head is 3~5mm.
8. The assembly structure according to claim 1, characterized in that: The tapered sleeve and the locking nut are an integrated structure or the gap between the tapered sleeve and the threaded shaft section is 0.05mm~0.2mm.
9. The assembly structure according to claim 1, characterized in that: The locking nut is a round nut.
10. The assembly structure according to claim 1, characterized in that: One end of the tapered sleeve that cooperates with the locking nut has a flange or a pair of lugs symmetrically arranged with each other; When a flange is used, two screw holes symmetrical to each other are opened on the flange; When ear plates are used, screw holes are provided on the ear plates.