Dynamic balance mandrel for dynamic balance test of impeller assembly and manufacturing method of dynamic balance mandrel

Abstract

The invention discloses a dynamic balance core shaft for testing dynamic balance of an impeller assembly and a manufacturing method of the dynamic balance core shaft. The dynamic balance core shaft is mainly formed by assembling a shaft body, a belt pulley and a cylindrical pin. The shaft body comprises a micro-cone cylindrical surface assembled and contacted with the impeller assembly, a shaft shoulder is arranged at the large end of the micro-cone cylindrical surface, and a cylindrical surface is arranged at the other end of the shaft shoulder; the belt pulley comprises a second cylindrical hole, and the second cylindrical hole and the cylindrical surface on the shaft body are assembled in an interference fit mode. The axial end face, close to the belt pulley, of the shaft body is provided with a core shaft cylindrical hole for dynamic balance testing, and the hole depth of the core shaft cylindrical hole for dynamic balance testing is used for adjusting the gravity center of the dynamic balance core shaft. The gravity center of the dynamic balance mandrel is adjusted to be within the installation supporting face of the impeller assembly without the positioning key, the distance between the gravity center of the impeller assembly and the gravity center of the dynamic balance mandrel is reduced as much as possible, and therefore it is ensured that the dynamic balance mass of the impeller assembly meets the design requirement.

Description

Technical Field

[0001] The invention relates to a mandrel for dynamic balancing test of an impeller, in particular to a dynamic balancing mandrel for dynamic balancing test of an impeller assembly and a manufacturing method thereof, belonging to the technical field of dynamic balancing test. Background Art

[0002] In order to cool down the working environment temperature of the airborne radar and enable the radar to work normally, a cooling fan is used as a solution. In order to evaluate the matching impeller assembly of the cooling fan ( Figure 1 ) The reliability of the welding structure, the impeller assembly is required to be tested for overspeed during the manufacturing process, and the dynamic balance is retested after the overspeed test. After the cooling fan is installed on the aircraft, the impeller assembly is driven by the motor to rotate. In order to obtain the required flow and pressure rise of cold air, the impeller assembly is designed as an ultra-thin large-diameter impeller (ultra-thin large-diameter impeller refers to: impeller diameter ≥ 200mm, impeller thickness ÷ impeller diameter ≤ 0.15), and there is no keyway in the impeller inner hole, and the impeller is assembled on the motor shaft without a positioning key. The operating speed of the impeller is 11000rpm, and the overspeed test speed is 13200rpm, running at this speed for 5min. Before the test, the impeller assembly is dimensionally inspected and dynamically balanced, and its allowable unbalance is not greater than 0.2g·cm. After the overspeed test, the impeller assembly is retested for size and dynamic balance quality. The result is that the size of the impeller assembly has not changed significantly, but the unbalance has changed greatly. The change in unbalance is specifically manifested in the following aspects:

[0003] 1) Before and after the overspeed test, the residual unbalance values ​​of the same impeller assembly vary, with the largest value exceeding +15% of the allowable measurement value, i.e., the measurement result before the overspeed test is 0.2g·cm, and the measurement result after the overspeed test is 0.23g·cm.

[0004] 2) Before the overspeed test, the residual unbalance value of the impeller assembly was re-measured several times, and the measurement results were recorded each time; after the overspeed test, the residual unbalance value of the impeller assembly was re-measured several times. Compared with the data before the overspeed test, the difference in the residual unbalance values ​​was large or small, and some exceeded the allowable error value of the two measurements;

[0005] 3) Before assembling the impeller assembly onto the dynamic balancing test shaft, mark lines on the surface of the impeller assembly and the dynamic balancing test shaft. After consciously changing the relative angular positions of the impeller assembly and the dynamic balancing test shaft one by one, perform a dynamic balancing test. The difference in the residual unbalance of the impeller assembly varies, but it is always possible to find an angular position where the residual unbalance before and after the overspeed test are basically equal. Then, at this angular position, remove the impeller assembly from the dynamic balancing shaft, and then reinstall the impeller assembly on the dynamic balancing test shaft for dynamic balancing retest. Repeat this several times, and the residual unbalance has good repeatability.

[0006] 4) In fact, when the impeller with a positioning key is dynamically balanced, the presence of the positioning key ensures the uniqueness of the installation position between the impeller and the dynamic balance test shaft, thereby ensuring that the residual unbalance has good repeatability. The unbalance of the impeller assembly changes with the distance and angular position (i.e. the angle between the two) between the unbalance of the impeller assembly and the unbalance of the dynamic balance test shaft.

[0007] The fundamental reason for the above changes is that the residual unbalance of the impeller assembly measured in the past is actually the vector sum U0 of the residual unbalance U1 of the impeller assembly itself and the residual unbalance U2 of the dynamic balancing test shaft. The magnitude of this vector sum U0 changes with the change of the angular position (i.e. the angle between the two) between the unbalance of the impeller assembly and the unbalance of the dynamic balancing test shaft.

[0008] The solution to this problem [see Figures 4 to 8 ] can be found on pages 89-90 of "Principles of Dynamic Balancing and Dynamic Balancing Machine" (Edited by Ye Neng'an and Yu Rusheng, published by Huazhong University of Science and Technology Press, first edition in December 1985, first printing in December 1985); it can also be found on pages 38-40 of "Balancing Technology" (Compiled by Heppnheim 1991 Hatto Schneider, Shanghai Schenck Machinery Co., Ltd.). The two solutions are actually one. Theoretically, they are valid, but it is very troublesome to implement them in practice.

[0009] Figure 4 In the figure, an auxiliary shaft with unbalance U1 is shown, with eccentricity e at the rotor mounting and axial runout;

[0010] Figure 5 A rotor with an unbalance U is shown in FIG.

[0011] Figure 6 The figure shows a rotor with an unbalance U, mounted on an auxiliary shaft with an unbalance U1, which also generates an unbalance U due to the mounting eccentricity e.偏 , the unbalance U caused by the rotor displacement of half a gap on the auxiliary shaft 间 The unbalanced amount U converted from the unbalanced force couple caused by axial runout 轴 , so the total unbalance is U 合 =U1+U+U 偏 +U 间 +U 轴 .

[0012] Figure 7 The figure shows that the rotor rotates 180° on the auxiliary shaft. At this time, U1 and U 偏 , U 间 , U 轴 The magnitude and direction of U remain unchanged, and U rotates 180° to become U', that is, U = -U'. Total unbalance U' 合 =U1+U'+U 偏 +U 间 +U 轴 .

[0013] Figure 8 The unbalance U measured by the secondary method is shown in 合 , U' 合 Subtract U 合 -U' 合 =2U'. The size and direction of U' can be obtained from the vector diagram.

[0014] It is obviously unrealistic to directly use the above solution for batch dynamic balancing of impeller rotors because its operability is too poor. The appearance of the parts will become very ugly due to the removal of excess metal by dynamic balancing with a 180° change of direction, and it is difficult to be recognized in terms of quality.

[0015] Can we find a good and easy-to-implement solution? After repeated research and verification, the applicant found that the magnitude of the impeller assembly's unbalance changes with the distance and angular position (i.e., the angle between the two) between the impeller assembly's unbalance and the unbalance of the dynamic balancing test shaft. The solution to this problem is to work hard on the design of the dynamic balancing shaft, adjust the center of gravity of the dynamic balancing shaft to the installation support surface of the impeller assembly, and minimize the distance between the center of gravity of the impeller assembly and the center of gravity of the dynamic balancing shaft. Summary of the invention

[0016] In order to overcome the defects existing in the existing impeller assembly dynamic balancing technology, the present invention aims to provide a dynamic balancing mandrel and a manufacturing method thereof that can be suitable for dynamic balancing testing of the impeller assembly, adjust the center of gravity of the dynamic balancing mandrel to within the mounting support surface of the impeller assembly (or adjust the center of gravity of the dynamic balancing mandrel to within the spatial area formed by the mounting support surface of the impeller assembly), and reduce the distance between the center of gravity of the impeller assembly and the center of gravity of the dynamic balancing mandrel as much as possible to ensure that the dynamic balancing quality of the impeller assembly meets the design requirements.

[0017] To achieve the above object, the present invention adopts the following technical solutions:

[0018] A dynamic balancing mandrel for dynamic balancing test of an impeller assembly:

[0019] The impeller assembly is an impeller without a positioning key;

[0020] The center of gravity of the dynamic balancing mandrel is located in the spatial area formed by the installation support surface of the impeller assembly, and the center of gravity of the dynamic balancing mandrel coincides with or tends to coincide with the center of gravity of the impeller assembly. The installation support surface is the surface of the impeller assembly to which the dynamic balancing mandrel exerts a supporting force when the impeller assembly and the dynamic balancing mandrel are assembled without a locating key.

[0021] As a solution, the impeller assembly is an impeller with a diameter ≥ 200 mm and an impeller thickness ÷ impeller diameter ≤ 0.15.

[0022] As a solution, the impeller assembly includes a mounting cylindrical hole, and the cylindrical surface of the inner wall of the mounting cylindrical hole serves as the mounting support surface.

[0023] As a solution, the dynamic balancing mandrel includes a shaft body, a pulley and a cylindrical pin, wherein the pulley is coaxially assembled on the shaft body, and the pulley is connected to the shaft body via a cylindrical pin perpendicular to the shaft body.

[0024] further,

[0025] The shaft body includes a micro-conical cylindrical surface that is in assembly contact with the impeller assembly, with a shaft shoulder at the large end of the micro-conical cylindrical surface and a cylindrical surface at the other end of the shaft shoulder; it should be pointed out that the micro-conical cylindrical surface is actually a conical surface, but because the taper is small, for example, the taper of the micro-conical cylindrical surface in the present invention is 1:3000, and it is close to a cylinder in appearance, so the micro-conical cylindrical surface is used for description.

[0026] The pulley comprises a second cylindrical hole, and the second cylindrical hole is assembled with the cylindrical surface on the shaft body by interference fit.

[0027] Furthermore, the pulley also includes a first cylindrical hole inside for reducing weight.

[0028] As a solution, a cylindrical hole for a dynamic balancing test mandrel is provided on the axial end face of the shaft body close to the pulley, and the depth of the cylindrical hole for the dynamic balancing test mandrel is used to adjust the center of gravity of the dynamic balancing mandrel.

[0029] A method for manufacturing a dynamic balancing mandrel for dynamic balancing test of an impeller assembly including a shaft body, a pulley and a cylindrical pin as described above, comprising:

[0030] S1, according to the diameter of the cylindrical hole of the impeller assembly, a micro-cone cylindrical surface is machined on the shaft body, and a shaft shoulder and a cylindrical surface are machined on the shaft body;

[0031] S2, machining a second cylindrical hole on the pulley according to the outer diameter of the cylindrical surface;

[0032] S3, assemble the shaft body and the pulley, and drill a pin hole at the matching position of the two, and then match a cylindrical pin according to the hole diameter of the pin hole to ensure that the cylindrical pin and the pin hole have an interference fit, and finally insert the cylindrical pin into the pin hole to complete the assembly of the dynamic balancing mandrel;

[0033] S4, a cylindrical hole for a dynamic balancing test mandrel is machined on the axial end face of the shaft body close to the pulley, and the center of gravity of the dynamic balancing mandrel is adjusted to a position close to half of the axial length of the micro-conical cylindrical surface by controlling the hole depth of the cylindrical hole for the dynamic balancing test mandrel.

[0034] Furthermore, the method for manufacturing a dynamic balancing mandrel for dynamic balancing test of an impeller assembly also includes S5: performing a dynamic balancing test on the dynamic balancing mandrel that has completed S4, and removing material from the surface of the pulley so that the residual imbalance of the dynamic balancing mandrel is less than or equal to the residual imbalance of the impeller assembly specified in the design.

[0035] Compared with the prior art, the present invention provides a new solution to the problem of dynamic balancing test of ultra-thin large-diameter impellers without positioning keys. The present invention is easy to implement, and after the implementation of the scheme of the present invention, when the impeller assembly is dynamically balanced before and after the overspeed test, the residual unbalance of the impeller assembly has good repeatability. At the same time, the dynamic balancing mandrel of the present invention has a simple structure, is easy to manufacture and use, and has high positioning and testing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of an ultra-thin large-diameter impeller assembly without a positioning key;

[0037] Figure 2 It is a structural schematic diagram of an existing mandrel for dynamic balancing test;

[0038] Figure 3 It is a structural schematic diagram of the assembly of the existing mandrel and impeller assembly for dynamic balancing test;

[0039] Figures 4 to 8 Schematic diagram of the theoretical method for removing the shaft unbalance for dynamic balancing test from the impeller unbalance;

[0040] Fig. 9 It is a schematic diagram of the structural requirements for the center of gravity design of the dynamic balancing mandrel in the present invention;

[0041] Fig.10 It is a schematic diagram of the shaft structure of the dynamic balancing core shaft in the present invention;

[0042] Fig.11 It is a schematic diagram of the pulley structure of the dynamic balancing mandrel in the present invention;

[0043] Fig.12 It is a schematic diagram of the cylindrical pin structure of the dynamic balancing mandrel in the present invention;

[0044] Fig.13 It is a schematic diagram of the assembly of the dynamic balancing mandrel and the impeller assembly in the present invention;

[0045] In the figure, 1 is an existing mandrel for dynamic balancing test, 2 is a dynamic balancing mandrel, 3 is a shaft body, 4 is a pulley, 5 is a cylindrical pin, 6 is an impeller assembly, 101 is a micro-conical cylindrical surface of an existing mandrel for dynamic balancing test, 102 is a center of gravity of an existing mandrel for dynamic balancing test, 201 is a center of gravity of a dynamic balancing mandrel, 202 is a cylindrical hole of a mandrel for dynamic balancing test, 301 is a micro-conical cylindrical surface, 302 is a cylindrical surface, 303 is a shoulder, 401 is a first cylindrical hole, 402 is a second cylindrical hole, 601 is a mounting cylindrical hole, and 602 is a center of gravity of an impeller assembly. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0047] In order to solve the dynamic balance test problem of ultra-thin large-diameter impeller without positioning keys, the present invention will Figure 2 The conventional dynamic balance test spindle 1 shown in the figure is modified to be Fig. 9 The dynamic balancing mandrel 2 is shown.

[0048] The center of gravity 102 of the conventional dynamic balancing test mandrel is located at the same position as the impeller assembly 6 (see Figure 1 ) of the mounting cylindrical hole 601 for assembling and positioning the micro-conical cylindrical surface 101 of the existing dynamic balancing test mandrel (see Figure 2), after the impeller assembly 6 is assembled on the existing dynamic balancing test mandrel 1, the center of gravity 102 of the existing dynamic balancing test mandrel is outside the axial thickness range of the impeller assembly 6, and the center of gravity 102 of the dynamic balancing test mandrel is far from the center of gravity 602 of the impeller assembly. The positional relationship between the center of gravity 102 of the dynamic balancing test mandrel and the center of gravity 602 of the impeller assembly is shown in FIG. Figure 3 .

[0049] As a comparison, the modified dynamic balancing mandrel 2 is mainly composed of a shaft body 3 (see Fig.10 ), pulley 4 (see Fig.11 ) and cylindrical pin 5 (see Fig.12 ) assembled.

[0050] According to the impeller assembly 6 (see Figure 1 ) of the mounting cylindrical hole 601, the positioning micro-conical cylindrical surface 301 of the shaft body 3 is designed (see Fig.10 ), the micro-cone cylindrical surface 301 is a conical surface, the outer diameter of the large end of which is equal to the maximum inner diameter of the mounting cylindrical hole 601, and the taper of the micro-cone cylindrical surface is 1:3000. A shaft shoulder 303 is designed at the large end of the micro-cone cylindrical surface 301 (see Fig.10 ), a cylindrical surface 302 is designed at the other end of the shoulder 303 (see Fig.10 ), used for interference fit assembly with the second cylindrical hole 402 of the pulley 4.

[0051] The second cylindrical hole 402 on the pulley 4 is designed according to the cylindrical surface 302 of the shaft body 3 (see Fig.11 ), so that an interference fit is formed between the two, and under the premise of meeting the strength requirements of the dynamic balance test, a first cylindrical hole 401 (see Fig.11 ).

[0052] After the shaft 3 and the pulley 4 are processed, Fig. 9 Assemble the pulley 4 on the shaft 3, and drill a pin hole at the matching position between the shaft 3 and the pulley 4, and make a cylindrical pin 5 according to the actual size of the pin hole (see Fig.12 ) to ensure that there is an interference fit between the cylindrical pin 5 and the pin hole. After the cylindrical pin 5 is assembled, press the cylindrical pin 5 into the pin hole to strengthen the positioning.

[0053] After the shaft body 3, the pulley 4 and the cylindrical pin 5 are assembled together to form the dynamic balance shaft 2 (see Fig. 9), and then punch a balancing test mandrel cylindrical hole 202 at the shaft end of the dynamic balancing mandrel 2, and adjust the center of gravity 201 of the dynamic balancing mandrel to about one-half of the axial length of the micro-cone cylindrical surface 301 by changing the depth of the balancing test mandrel cylindrical hole 202 at the shaft end. It should be pointed out that the reason for adjusting to about one-half of the axial length of the micro-cone cylindrical surface 301 is that there are manufacturing deviations in the actual processing process, and it is difficult to accurately adjust the center of gravity 201 of the dynamic balancing mandrel to one-half of the axial length of the micro-cone cylindrical surface 301. Generally, the center of gravity 201 of the dynamic balancing mandrel can be adjusted to a position close to one-half of the axial length of the micro-cone cylindrical surface 301.

[0054] After the impeller assembly 6 is assembled on the dynamic balancing mandrel 2, the center of gravity 602 of the impeller assembly and the center of gravity 201 of the dynamic balancing mandrel are both located within the axial thickness range of the impeller assembly 6 (equivalent to adjusting the center of gravity 201 of the dynamic balancing mandrel to within the mounting support surface of the impeller assembly 6, Fig.13 The axial thickness is more intuitive in the description). The positional relationship between the two is shown in Fig.13 .

[0055] Compared with the prior art, due to the solution of the present invention, the impeller assembly 6 and the dynamic balance shaft 2 can be assembled into a whole by inserting the micro-conical cylindrical surface 301 on the shaft body 3 into the mounting cylindrical hole 601 of the impeller assembly 6 for positioning (mounting support) (see FIG. Fig.13 By changing the depth of the cylindrical hole 202 of the shaft end for dynamic balancing test, the center of gravity 201 of the dynamic balancing shaft can be adjusted to about half of the axial length of the cylindrical hole 601 of the impeller assembly 6 (see Fig.13 ), effectively solving the problem that the center of gravity 102 of the existing dynamic balancing test mandrel deviates from the installation cylindrical hole 601 of the impeller assembly 6, resulting in a large system error in the dynamic balancing test. Therefore, the impeller assembly 6 can be dynamically balanced according to the requirements of the process regulations, and the impeller assembly 6 can be dynamically balanced before and after the overspeed test. The residual unbalance of the impeller assembly 6 has good repeatability. The dynamic balancing mandrel 2 of the present invention has a simple structure, is easy to manufacture and use, and has high positioning and testing accuracy.

[0056] The manufacturing method of the dynamic balancing mandrel 2 is as follows:

[0057] 1) According to the impeller assembly 6 (see Figure 1 ) of the mounting cylindrical hole 601, and the positioning micro-conical cylindrical surface 301 of the machining shaft body 3 (see Fig.10 ), a shoulder 303 is machined at the large end of the micro-cone cylindrical surface 301 (see Fig.10 ), a cylindrical surface 302 is machined at the other end of the shoulder 303 (see Fig.10), used for interference fit assembly with the second cylindrical hole 402 of the pulley 4.

[0058] 2) Design the second cylindrical hole 402 on the pulley 4 according to the cylindrical surface 302 of the shaft body 3 (see Fig.11 ), so that an interference fit is formed between the two, and under the premise of meeting the strength requirements of the dynamic balance test, a first cylindrical hole 401 (see Fig.11 ).

[0059] 3) After the shaft 3 and the pulley 4 are processed, Fig. 9 , assemble the pulley 4 on the shaft body 3, and drill a pin hole at the matching position between the shaft body 3 and the pulley 4, and make a cylindrical pin 5 according to the actual size of the pin hole (see Fig.12 ) to ensure that there is an interference fit between the cylindrical pin 5 and the pin hole. After the cylindrical pin 5 is assembled, press the cylindrical pin 5 into the pin hole to strengthen the positioning.

[0060] 4) After the shaft 3, pulley 4 and cylindrical pin 5 are assembled together to form the dynamic balancing mandrel 2 (see Fig. 9 ), and then punch a cylindrical hole 202 for a dynamic balancing test mandrel at the shaft end of the dynamic balancing mandrel 2, and adjust the center of gravity 201 of the dynamic balancing mandrel to approximately one-half of the axial length of the micro-conical cylindrical surface 301 by changing the depth of the cylindrical hole 202 for a dynamic balancing test mandrel at the shaft end.

[0061] 5) Perform a dynamic balancing test on the dynamic balancing mandrel 2 and remove unbalanced metal on the pulley 4, so that the remaining unbalance of the dynamic balancing mandrel 2 is no more than one tenth of the remaining unbalance value of the impeller assembly 6 specified in the design.

[0062] The method of performing an overspeed test and a dynamic balancing test using the dynamic balancing mandrel 2 of the present invention is as follows:

[0063] 1) Assemble the impeller assembly 6 on the dynamic balancing mandrel 2, and perform dynamic balancing test and correction on the impeller assembly 6 according to the requirements of the process regulations, so that its residual unbalance amount reaches the technical indicators specified in the design;

[0064] 2) According to the requirements of the process regulations, the impeller assembly 6 that has passed the dynamic balance test is subjected to an overspeed test;

[0065] 3) The impeller assembly 6 that has completed the overspeed test is assembled on the dynamic balancing core shaft 2, and the impeller assembly 6 is dynamically balanced again according to the requirements of the process regulations. The residual unbalance amount reaches the technical indicators specified in the design, indicating that the residual unbalance amount of the impeller assembly 6 has good repeatability.

[0066] After adopting the dynamic balancing mandrel 2 of the present invention, the dynamic balancing of the impeller assembly 6 meets the design technical index requirements, and it is assembled in a cooling fan for identification test assessment. The fan passes the long-term operation life test assessment, and at the same time, it also passes the field installation and use assessment, indicating that the dynamic balancing quality of the impeller assembly 6 has been fully verified. The present invention improves the dynamic balancing technology of ultra-thin large-diameter impellers without locating keys, and also provides a simple, economical and practical solution for the dynamic balancing of impellers of the same type.

[0067] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A dynamic balancing mandrel for dynamic balancing test of an impeller assembly, characterized in that: The impeller assembly (6) is an impeller without a positioning key; The center of gravity (201) of the dynamic balancing core shaft is located within a spatial region formed by a mounting support surface of the impeller assembly (6), and the center of gravity (201) of the dynamic balancing core shaft coincides with or tends to coincide with the center of gravity (602) of the impeller assembly. The mounting support surface is the surface of the impeller assembly (6) on which a supporting force is applied by the dynamic balancing core shaft (2) when the impeller assembly (6) and the dynamic balancing core shaft (2) are assembled without a positioning key.

2. A dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 1, characterized in that: The impeller assembly (6) is an impeller with a diameter of ≥200 mm and an impeller thickness ÷ impeller diameter ≤0.

15.

3. The dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 1, characterized in that: The impeller assembly (6) comprises a mounting cylindrical hole (601), and the cylindrical surface of the inner wall of the mounting cylindrical hole (601) serves as a mounting support surface.

4. The dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 1, characterized in that: The dynamic balancing mandrel (2) comprises a shaft body (3), a pulley (4) and a cylindrical pin (5), wherein the pulley (4) is coaxially assembled on the shaft body (3), and the pulley (4) is connected to the shaft body (3) via the cylindrical pin (5) perpendicular to the shaft body (3).

5. A dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 4, characterized in that: The shaft body (3) comprises a micro-conical cylindrical surface (301) which is in contact with the impeller assembly (6) for assembly, a shaft shoulder (303) at the large end of the micro-conical cylindrical surface (301), and a cylindrical surface (302) at the other end of the shaft shoulder (303); The pulley (4) comprises a second cylindrical hole (402), and the second cylindrical hole (402) is assembled with a cylindrical surface (302) on the shaft body (3) by interference fit.

6. A dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 4, characterized in that: The pulley (4) further comprises a first cylindrical hole (401) inside for reducing weight.

7. A dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 4, characterized in that: A dynamic balancing test spindle cylindrical hole (202) is provided on the axial end face of the shaft body (3) close to the pulley (4), and the depth of the dynamic balancing test spindle cylindrical hole (202) is used to adjust the center of gravity (201) of the dynamic balancing spindle.

8. A method for manufacturing a dynamic balancing mandrel for dynamic balancing test of an impeller assembly as claimed in claim 5, characterized in that: include: S1, machining a micro-conical cylindrical surface (301) on the shaft body (3) according to the aperture of the mounting cylindrical hole (601) of the impeller assembly (6), and machining a shaft shoulder (303) and a cylindrical surface (302) on the shaft body (3); S2, machining a second cylindrical hole (402) on the pulley (4) according to the outer diameter of the cylindrical surface (302); S3, assemble the shaft body (3) and the pulley (4), and drill a pin hole at the matching position of the two, and then make a cylindrical pin (5) according to the hole diameter of the pin hole, ensure that the cylindrical pin (5) and the pin hole have an interference fit, and finally insert the cylindrical pin (5) into the pin hole to complete the assembly of the dynamic balancing core shaft (2); S4, a cylindrical hole (202) for a dynamic balancing test mandrel is machined on the axial end face of the shaft body (3) close to the pulley (4), and the center of gravity (201) of the dynamic balancing mandrel is adjusted to a position close to half of the axial length of the micro-conical cylindrical surface (301) by controlling the hole depth of the cylindrical hole (202) for the dynamic balancing test mandrel.

9. The method for manufacturing a dynamic balancing mandrel for dynamic balancing test of an impeller assembly according to claim 8, characterized in that: The method further includes S5: performing a dynamic balancing test on the dynamic balancing core shaft (2) that has completed S4, and removing material from the surface of the pulley (4) so ​​that the residual unbalance amount of the dynamic balancing core shaft (2) is less than or equal to the residual unbalance amount of the impeller assembly (6) specified in the design.

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