Shaft end locking mechanism of high-speed rotating shaft

Abstract

The invention discloses a shaft end locking mechanism of a high-speed rotating shaft, and belongs to the field of high-speed motor driving. The invention discloses a shaft end locking mechanism of a high-speed rotating shaft, which aims to meet the requirements when a motor shaft is used on a high-speed rotating occasion, and comprises a shaft which bears a series of parts and then is driven by a high-speed motor to rotate at a high speed, the shaft end part serves as an end cover and is used for preventing related parts on the shaft from axially moving, a pair of coaxial concave-convex matching surfaces are arranged between the high-speed rotating shaft and the shaft end part and serve as assembling and positioning references, and the shaft end part and the high-speed rotating shaft are connected, locked and fixed through screws in the axial direction. The fixing device is mainly used for fixing the shaft end of an impeller driven by a high-speed motor and the shaft end of an air suspension bearing.

Description

Technical Field

[0001] The invention belongs to the field of high-speed motor drive, and in particular relates to a shaft end locking mechanism for a high-speed rotating shaft. Background Art

[0002] For any motor-driven system, after the rotating shaft of the motor carries a series of components, a shaft end locking mechanism will be configured at the shaft end for axial locking and fixation to ensure the stability and reliability of the entire system during operation. Especially for the rotating shaft of a high-speed motor, the requirements for the shaft end locking mechanism are often higher. For example, the high-speed rotating shaft after installing air bearings, impellers and other components has very high requirements for the dynamic balance of the shaft end, and shaft end locking is particularly important.

[0003] Traditional rotating shaft end locking mechanism, such as Figure 1 As shown, threaded holes and through holes are usually opened axially from the end face of the motor shaft 2, and then the pull rod 14 and the nut 13 are used as connecting parts. The torque is transmitted by relying on the preload force of the pull rod 14 and the roughness of the mounting surface to connect and lock the shaft end part 1 with the motor shaft 2. When the torque to be transmitted is large and due to structural reasons, the cross-section of the pull rod 14 allowed to be selected may be smaller, and the pull rod material needs to have a sufficiently large yield strength to provide preload force to obtain torque. For this reason, the pull rod 14 and the nut 13 are usually made of materials with higher yield strength, and are usually non-standard customized parts, which are inconvenient to manufacture and costly. Moreover, it is obvious that the coaxiality of the motor shaft and the shaft end parts is not easy to ensure. Summary of the invention

[0004] The present invention aims to solve several defects of the above-mentioned traditional shaft end locking structure when used on a high-speed rotating shaft driven by a high-speed motor.

[0005] To this end, the present invention provides a shaft end locking mechanism for a high-speed rotating shaft, which includes a shaft that carries a series of components and is driven by a high-speed motor to rotate at high speed, and also includes a shaft end part serving as an end cover to prevent axial movement of related components on the shaft. Between the high-speed rotating shaft and the shaft end part, there is a pair of coaxial concave and convex mating surfaces as assembly positioning references, and the shaft end part and the high-speed rotating shaft are connected and locked along the axial direction with screws.

[0006] A further optimization is that the height of the convex surface is not greater than the depth of the concave surface, and a plurality of evenly distributed shoulder screws are used to connect the shaft end part and the high-speed rotating shaft along the axial direction and then locked and fixed.

[0007] A further optimization is that the plurality of shoulder screws evenly distributed along the axial direction are located at positions avoiding the concave and convex matching surfaces.

[0008] As a preferred solution, the shaft end part is a thin-walled part, the convex surface is arranged on the shaft end part, the concave surface is arranged at the shaft end of the high-speed rotating shaft, and the plurality of shoulder screws evenly distributed along the axial direction are located at the positions of the concave and convex matching surfaces.

[0009] As another preferred solution, the convex surface is cylindrical (or conical) at the shaft end, and the concave surface is a coaxially complementary hole on the shaft end part; and three evenly distributed shoulder screws are used.

[0010] Furthermore, the convex surface is a finely machined boss on the shaft end; the concave surface is a finely machined center hole on the shaft end part; the shoulder screw contains a threaded section and a precision section; the shaft end of the high-speed rotating shaft is provided with a threaded hole and a finely machined smooth hole; the shaft end part contains a finely machined smooth screw hole; wherein, the total length of (shaft end threaded hole 4 + shaft end finely machined hole 5 + finely machined smooth screw hole 8 of shaft end part 1) is not less than the total length of (threaded section 10 + precision section 11) of the shoulder screw, and the remaining thickness of the shaft end part is the length reserved for the countersunk hole.

[0011] After the implementation of the above-mentioned series of related technical solutions, the shaft end parts can achieve a highly concentric connection with the high-speed rotating shaft, and the dynamic balance test results of the entire assembly during high-speed rotation are quite satisfactory. After adopting this shaft end locking mechanism, disassembly and assembly are also convenient, and because the screw has high matching accuracy, repeated disassembly and assembly will not affect the dynamic balance data, so the material requirements for the connecting parts are not high, and standard screw parts can also be used for connection. Therefore, the use of the shaft end locking mechanism of the high-speed rotating shaft reduces the difficulty of designing, processing, and manufacturing the overall structure of the product.

[0012] One of the actual application scenario cases is an impeller assembly that is driven by a high-speed motor shaft. The shaft end where the impeller is installed is equipped with the above-mentioned shaft end locking mechanism to lock and fix the impeller, thereby achieving safe, stable high-speed rotation and dynamic balance of the impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A series of diagrams used in the present invention are listed here: Figure 1 Schematic diagram of a traditional motor shaft end locking mechanism, wherein: 1 is a shaft end part; 2 is a motor shaft; 12 is a gasket; 13 is a nut; and 14 is a pull rod.

[0014] Figure 2 An assembly diagram of a shaft end locking mechanism for a high-speed rotating shaft; Figure 3 An assembly exploded view of a shaft end locking mechanism for a high-speed rotating shaft; wherein: 1 shaft end parts; 2 high-speed rotating shaft; 3 shoulder screw; 4 threaded hole on the shaft; 4 fine-machined hole on the shaft; Finishing boss on 6-axis; finishing center hole of 7-axis end parts; finishing shoulder screw hole of 8-axis end parts; 9. Countersunk hole for shoulder screw of shaft end parts; 10. Thread section for shoulder screw; 11. Precision section for shoulder screw Figure 4 Schematic diagram of the shaft end locking mechanism of the high-speed rotating shaft of the second embodiment, wherein: 1 shaft end parts; 2 motor shaft; 3 shoulder screw; Figure 5 An impeller assembly installed using the shaft end locking mechanism, wherein: 2 high-speed rotating shaft; 3 shoulder screw; 15 front impeller; 16 front bearing seat; 17 motor housing; 18 rear bearing seat; 19 rear impeller; 20 rear impeller housing Specific embodiments

[0015] Based on the ideas of the above series of technical solutions, three specific embodiments are now listed.

[0016] Embodiment 1: like Figure 2 As shown, the present embodiment discloses a shaft end locking mechanism for a high-speed rotating shaft, comprising a high-speed rotating shaft 2 driven by a high-speed motor, and also comprising a shaft end part 1 serving as an end cover for preventing axial movement of related parts on the shaft, and between the high-speed rotating shaft 2 and the shaft end part 1, there is a pair of coaxial concave-convex mating surfaces serving as assembly positioning references, and the shaft end part 1 and the high-speed rotating shaft 2 are connected and fixed along the axial direction with screws.

[0017] like Figure 3 As shown, in this embodiment, the shaft end finish-machined boss 6 of the high-speed rotating shaft 2 is cylindrical; there is a complementary concave surface on the shaft end part 1, that is, the finish-machined center hole 7 of the shaft end part 1, the two are in a coaxial assembly relationship, and the depth of the concave surface is greater than the height of the boss; the concave and convex matching parts are avoided, and the high-speed rotating shaft 2 and the shaft end part 1 are connected by screws, and three evenly distributed shoulder screws are preferably used.

[0018] During the design process, the core part of the shoulder screw 3, that is, the values ​​of the shoulder screw thread section 10 and the shoulder screw precision section 11, is first determined. Then the threaded hole 4 on the shaft, the fine-machined hole 5 on the shaft and the fine-machined shoulder screw hole 8 of the shaft end part corresponding to the shoulder screw 3 can be determined. Finally, the remaining part of the shaft end part 1 is the size of the countersunk hole 9 reserved for the shoulder screw 3. When the shaft end part 1 is very thin, there may not be a chance for the countersunk hole 9 to exist, but the presence or absence of the countersunk hole 9 is also irrelevant. What is important is the coaxial precision matching of the concave and convex surfaces and the tightening of the screws.

[0019] In this embodiment, when the shoulder screw 3 is selected, the specific formula for calculating its core part is as follows: (1) Threaded section 10 of shoulder screw 3: Since shoulder screw 3 is subject to shear force, the shear strength of shoulder screw 3 is calculated. Calculation of shear force

[0020] : Total shear force T: Torque d: The pitch circle diameter of the shoulder screw (2) The diameter of the precision section 11 of the shoulder screw 3 :

[0021]

[0022]

[0023]

[0024] : Shear stress : Shear force : Shear area n: number of screws : 3 shoulder screws 11 places diameter : Shear Strength Select the appropriate diameter shoulder screw based on the calculated theoretical value ⑶ Calculation method for the length of finishing holes 5 and 8: There is extrusion force here, calculated by extrusion strength

[0025] P: Extrusion force A: Force bearing area = ; L: The length of the bolt and the hole : Extrusion stress : Crushing strength Here the extrusion force is equal to the shear force, so

[0026]

[0027] so

[0028] Based on the above, the minimum length L of the bolt and the hole can be calculated, and then the appropriate size of the shoulder screw 3 can be selected according to the specific structure.

[0029] Embodiment 2: like Figure 4 In the shaft end locking mechanism of a high-speed rotating shaft shown in the figure, the shaft end part 1 is a thin-walled part. When the torque to be transmitted is large, in order to reduce the extrusion stress between the shaft end part 1 and the shoulder screw 3 and prevent the shaft end part 1 from being crushed, the difference from the above-mentioned embodiment 1 is that: there is a pair of coaxial concave-convex matching surfaces between the high-speed rotating shaft 2 and the shaft end part 1, the convex surface is on the shaft end part 1, and the concave surface is on the shaft end of the rotating shaft 2, and the two are coaxially matched; the shoulder screw 3 is arranged on the concave-convex matching surface, so the matching surface between the shoulder screw 3 and the shaft end part 1 is lengthened, and the extrusion stress is reduced.

[0030] Embodiment 3: like Figure 5 What is shown is an impeller assembly driven by a high-speed motor, the impeller assembly includes a motor housing 17 of the high-speed motor, a motor shaft 2, and a front bearing seat 16 and a rear bearing seat 18 required for the motor shaft 2 at both ends of the motor housing 17; it also includes a front impeller 15 and a rear impeller 19 installed at both ends of the motor shaft 2, and the rear impeller 19 is equipped with a rear impeller housing 20; the front impeller 15 and the rear impeller 19 are fixed at the shaft end, and the shaft end locking mechanism in embodiment one or embodiment two is adopted.

[0031] In addition to the three specific embodiments disclosed above, other more technical solutions can be designed and implemented according to the concept of the present invention. For example, other numbers of shoulder screws can be evenly distributed; conical concave and convex surfaces can also be used, which should have a better stabilizing effect. All these technical solutions inspired by the same idea should fall within the scope of protection required by the present invention.

[0032] In summary, the implementation of the technical solution of the present invention has good actual experience effect and has the following advantages: 1. The parts connection is highly concentric; 2 Because it is fixed with evenly spaced screws, the extremely important dynamic balance data will not be damaged; 3. Easy to disassemble and assemble, and because the screw has high matching accuracy, disassembly and assembly will not affect the dynamic balance data; 4 It reduces the difficulty of designing, processing and manufacturing the overall structure, and standard parts can be used; and the material requirements for connecting parts are low.

[0033] The shaft end locking mechanism adopted by the present invention solves the defects of the traditional shaft end locking mechanism when used on the high-speed rotating shaft driven by the high-speed motor; it is very suitable for use in various products driven by high-speed motors, in addition to impellers, there are also shaft end locking of high-speed motor shafts of products such as air suspension blowers and compressors, so that the performance of the whole machine can be more fully exerted.

Claims

1. A high-speed rotating shaft end locking mechanism, comprising a high-speed rotating shaft (2) that carries a series of components and is driven by a high-speed motor, and also comprising a shaft end part (1) for preventing axial movement of related components on the shaft, characterized in that: A pair of coaxial concave-convex mating surfaces are provided between the high-speed rotating shaft (2) and the shaft end part (1) as assembly positioning references, and the shaft end part (1) and the high-speed rotating shaft (2) are locked and connected along the axial direction using screws.

2. The shaft end locking mechanism for a high-speed rotating shaft according to claim 1, characterized in that: The depth of the concave surface (7) is not less than the height of the convex surface (6), and a plurality of shoulder screws (3) are evenly distributed along the axial direction.

3. The shaft end locking mechanism for a high-speed rotating shaft according to claim 2, characterized in that: The shaft end part (1) is a thin-walled part, the convex surface (6) is arranged on the shaft end part (1), the concave surface 7 is arranged at the shaft end of the high-speed rotating shaft (2), and the plurality of shoulder screws (3) evenly distributed along the axial direction are arranged at the positions of the concave and convex matching surfaces.

4. The shaft end locking mechanism for a high-speed rotating shaft according to claim 2, characterized in that: The convex surface (6) is cylindrical (or conical) at the shaft end, and the concave surface is a coaxially complementary hole on the shaft end part (1); and the plurality of shoulder screws (3) evenly distributed along the axial direction are arranged at a position avoiding a pair of coaxial concave-convex matching surfaces.

5. The shaft end locking mechanism for a high-speed rotating shaft according to claim 2, characterized in that: The convex surface (6) is a shaft end finely machined boss (6); the concave surface (7) is a shaft end part finely machined center hole (7); the shoulder screw (3) comprises a threaded section (10) and a precision section (11); the shaft end of the high-speed rotating shaft (2) is provided with a threaded hole (4) and a finely machined smooth hole (5); the shaft end part (1) comprises a finely machined smooth screw hole (8); wherein the total length of "shaft end threaded hole (4) + shaft end finely machined hole (5) + finely machined smooth screw hole (8) of the shaft end part (1)" is greater than the total length of the shoulder screw (3) (threaded section 10 + precision section 11), and the remaining thickness of the shaft end part (1) is the length reserved for the countersunk hole (9).

6. The shaft end locking mechanism for a high-speed rotating shaft according to claim 5, characterized in that: The plurality of shoulder screws (3) evenly distributed along the axial direction are provided in three pieces.

7. An impeller assembly driven by a high-speed motor, comprising a high-speed motor stator and a motor housing (17), a high-speed rotating shaft (2) of the motor, wherein the motor housing (17) has a front bearing seat (16) and a rear bearing seat (18) configured for the high-speed rotating shaft (2) at both ends; and further comprising impellers mounted on both ends of the high-speed rotating shaft (2), namely a front impeller (15) and a rear impeller (19), wherein the rear impeller (19) is provided with a rear impeller housing (20); characterized in that: The impeller assembly adopts the shaft end locking mechanism of the high-speed rotating shaft as described in any of the above claims, and is installed on the two shaft ends of the high-speed rotating shaft (2) of the motor to complete the axial locking and fixation of the front impeller (15) and the rear impeller (19).

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