Method for controlling initial unbalance of combined rotor

Abstract

The invention discloses a method for controlling the initial unbalance of a combined rotor, and the method comprises the steps: firstly, respectively determining the balance mode of each part, then calculating the standard residual unbalance of each part, and then carrying out the balance correction of each part until the final residual unbalance of each part is close to or reaches the standard residual unbalance. The method comprises the following steps of: recording the value and the position direction of the final residual unbalance of the parts, calculating the assembly angle of the parts according to the value and the position direction of the final residual unbalance, assembling the parts into a combined rotor according to the assembly angle, and finally detecting the initial unbalance of the combined rotor. And the final residual unbalance of the combined rotor is corrected. According to the method, the initial unbalance amount of the assembly is controlled to be minimized by controlling the assembly angle of the parts, the yield of one-time assembly is increased, the weight removal amount or the weight increase amount is reduced, the problem that vibration is generated due to local bending caused by couple unbalance is solved, and the yield of products is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of combined rotor unbalance control, and in particular to a method for controlling the initial unbalance of a combined rotor. Background Art

[0002] At present, most shaft-based combined rotors are assembled randomly, and then dynamically balanced as a whole, and the required dynamic balancing accuracy is achieved by reducing or adding weight to a certain part. The existing random assembly method will result in a large initial imbalance, which will lead to a large amount of weight removal or weight addition, and may even fail to meet the requirements of weight removal or weight addition. Due to the randomness of assembly, it is easy to have problems with disassembly and reassembly, resulting in a low qualified rate for one-time assembly of the combined rotor. Even if the assembly can be balanced through dynamic balancing operations, as the speed of the combined rotor increases, the unbalanced force and couple of the combined rotor will also increase, causing local bending of the shaft to produce vibration, which in turn causes the product to fail to work properly. Summary of the invention

[0003] The purpose of the present invention is to provide a method for controlling the initial unbalance of a combined rotor in response to the above-mentioned problems, thereby minimizing the initial unbalance of the assembly by controlling the angle of part assembly, increasing the qualified rate of a single assembly, reducing weight removal or addition, solving the problem of vibration caused by local bending caused by unbalanced couple, and effectively improving the qualified rate of the product.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0005] According to one aspect of the present invention, a method for controlling the initial unbalance of a combined rotor is provided, comprising the following steps:

[0006] S1, respectively determining a balancing method for correcting each part of the combined rotor;

[0007] S2. Calculate the standard residual unbalance of each part according to the balancing method corresponding to the part;

[0008] S3, performing balance correction on each part respectively until the final residual unbalance of the part approaches or reaches the standard residual unbalance, and recording the value and position direction of the final residual unbalance of the part;

[0009] S4, calculating the assembly angle of the part according to the value and position direction of the final remaining unbalance;

[0010] S5, assembling the parts into a combined rotor according to the assembly angle;

[0011] S6. Performing an initial unbalance detection on the combined rotor and correcting a final remaining unbalance of the combined rotor.

[0012] Preferably, in step S1, the method for determining the balancing mode of the part is:

[0013] Determine the balancing method according to the ratio of the diameter D to the thickness B of the part;

[0014] When D / B ≥ 5, the parts are corrected by static balancing;

[0015] When D / B<5, the parts are corrected by dynamic balancing.

[0016] Preferably, in step S2, the standard residual unbalance of the part corrected by the static balancing method is calculated by the following formula, specifically:

[0017]

[0018] Among them, m per is the allowable residual unbalanced mass, in g; m is the mass of the balanced part, in kg; G is the balancing accuracy, in mm / s; n is the maximum continuous operating speed, in r / min; r is the radius where the residual unbalance is located, in mm.

[0019] Preferably, in step S2, the standard residual unbalance of the part corrected by the dynamic balancing method is calculated by the following formula, specifically:

[0020]

[0021] Among them, U per is the maximum allowable residual unbalance on each plane, in g.mm; W is the static load of a single support journal, in N; n is the maximum continuous operating speed, in r / min.

[0022] Preferably, in step S4, the assembly angle of the parts is determined by the minimum value of the combined unbalance, and the combined unbalance is:

[0023]

[0024] Among them, U x It is the objective function of decomposing all unbalanced quantities into components on the X-axis of the projection plane; U y It is the objective function that decomposes all unbalanced quantities into components on the Y-axis of the projection plane.

[0025] Preferably, the objective function U x for:

[0026]

[0027] Among them, U i is the unbalance value of the i-th part; α i is the position direction of the unbalance of the i-th part.

[0028] Preferably, the objective function U y for:

[0029]

[0030] Among them, U i is the unbalance value of the i-th part; α i is the position direction of the unbalance of the i-th part.

[0031] Preferably, in step S5, the assembly method of assembling the parts into the combined rotor is:

[0032] During the assembly process of each part, the axial runout and radial runout range of each part on the axis of the combined rotor is ≤0.01mm.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] The present invention controls the angle of parts assembly so that the initial unbalance of the combined rotor is within a controllable range, and can reduce the weight removal when performing final residual unbalance control, thereby improving efficiency. At the same time, it also avoids the randomness of random assembly and avoids repeated assembly due to excessive weight removal, thereby effectively solving the problem of transcritical vibration and improving the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the process of the present invention;

[0036] Figure 2 It is a schematic diagram of the combined rotor structure in an example of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the invention, and these aspects of the present invention can be realized even without these specific details.

[0038] See also Figure 1 The present invention provides a method for controlling the initial unbalance of a combined rotor, and the technical solution is as follows:

[0039] A method for controlling the initial unbalance of a combined rotor comprises the following steps:

[0040] S1. Determine the balancing method of each part: Determine the balancing method of each part used to correct the combined rotor.

[0041] Specifically, the unbalanced mode of each component constituting the combined rotor is determined according to the characteristics of the components. In this embodiment, the balancing mode is determined according to the ratio of the diameter D of the component to its thickness B.

[0042] When D / B ≥ 5, the parts are corrected by static balancing;

[0043] When D / B<5, use dynamic balancing to correct the parts.

[0044] By calculating the ratio of the diameter D to the thickness B of each part, and then according to the above ratio range, the balancing method adopted for each part to be corrected is determined.

[0045] S2. Calculate the standard residual unbalance of each part: Calculate the standard residual unbalance of each part according to the balancing method corresponding to each part.

[0046] Specifically, when D / B≥5, the parts are corrected by static balancing. In this embodiment, the ISO1940 standard is used to calculate the standard residual unbalance for the static balancing method. The standard residual unbalance is calculated by the following formula:

[0047]

[0048] Among them, m per To allow for residual unbalanced mass, in g;

[0049] m is the mass of the part being balanced, in kg;

[0050] G is the balancing accuracy, in mm / s;

[0051] n is the maximum continuous operating speed, in r / min;

[0052] r is the radius of the residual unbalance, in mm.

[0053] When D / B is less than 5, the parts are corrected by dynamic balancing. In this embodiment, the standard residual unbalance is calculated with reference to the API617 with higher accuracy for the dynamic balancing method. The standard residual unbalance is specifically calculated by the following formula:

[0054]

[0055] Among them, Uper The maximum allowable residual unbalance on each plane, in g.mm;

[0056] W is the static load of a single support journal, in N;

[0057] n is the maximum continuous operating speed, in r / min.

[0058] According to the above calculation formula, the standard residual unbalance of each part is calculated respectively.

[0059] S3. Make balance corrections to the parts separately: Make balance corrections to each part separately until the final residual unbalance of the part approaches or reaches the standard residual unbalance, and record the value and position direction of the final residual unbalance of the part.

[0060] Specifically, balance correction is performed on each part so that the final unbalance amount is close to or reaches the calculated standard residual unbalance amount, and the size and position direction of the final residual unbalance amount are recorded during the correction process. The final unbalance amount is an amount that does not exceed the standard residual unbalance amount, that is, the final unbalance amount is less than or equal to the standard unbalance amount. In this embodiment, the final residual unbalance amount is equivalent to the standard unbalance amount. For example, during the correction process, if the residual unbalance amount has reached the calculated standard residual unbalance amount, then the residual unbalance amount is the final residual unbalance amount; if during the correction process, the residual unbalance amount cannot reach the standard residual unbalance amount, then the residual unbalance amount closest to the standard residual unbalance amount is selected as the final residual unbalance amount.

[0061] According to the above method, the size and position direction of the final remaining unbalance of the part are obtained.

[0062] S4. Calculate the optimal assembly angle: Calculate the assembly angle of the parts according to the value and position direction of the final remaining unbalance.

[0063] Specifically, the assembly direction of each part is calculated based on the principle of minimum combined unbalance. Assume that the unbalance of each part is U i , direction is α i , decomposing all the unbalanced quantities into the two coordinate systems of the projection plane, we can get the objective function as follows:

[0064]

[0065] Among them, U x The objective function for decomposing all unbalanced quantities into components on the X-axis of the projection plane;

[0066] U y The objective function is to decompose all the unbalanced quantities into the components on the Y-axis of the projection plane;

[0067] U i is the unbalance magnitude of the i-th part;

[0068] α i is the position direction of the unbalance of the i-th part.

[0069] From the above two objective functions, the synthetic imbalance is obtained:

[0070]

[0071] According to the formula of the combined unbalance, the size of the residual unbalance and the assembly angle of each part can be obtained respectively in order to obtain the principle of minimum combined unbalance.

[0072] S5. Assemble the combined rotor according to the assembly requirements: assemble the various parts into a combined rotor according to the assembly angle.

[0073] Specifically, the parts are assembled into a combined rotor based on the assembly angles of the parts calculated according to the principle of minimum combined unbalance.

[0074] Among them, even if the assembly is carried out according to the principle of minimizing the synthetic imbalance, it is still possible that the initial imbalance of the component is large. In order to solve this problem, in this embodiment, it is necessary to assemble according to the following assembly method. Specifically: the axial runout and radial runout of each part on the combined axis, the radial and axial runouts must be controlled within 0.01mm, and this range is optimal.

[0075] S6. Detecting the initial unbalance amount of the combined rotor: Detecting the initial unbalance amount of the combined rotor and correcting the final remaining unbalance amount of the combined rotor.

[0076] Specifically, the initial unbalance amount of the combined rotor dynamic balance is detected, and then the final remaining unbalance amount is corrected according to API 617. The initial dynamic balancing test results show that this method can effectively reduce the initial unbalance amount.

[0077] It should be noted that the object of the present invention is a high-speed shafting assembly, whose rotational speed is between the first and second critical speeds, and is a semi-flexible rotor. In engineering, such rotors are generally subjected to low-speed dynamic balancing according to rigid rotor standards as quasi-rigid rotors.

[0078] Examples:

[0079] The high-speed rotor of a compressor is used as the implementation object. The rotor mass is 5.94kg and the running speed is 37000r / min. The combined rotor is as follows: Figure 2 shown.

[0080] The balancing method used for each part is determined according to its characteristics, and then the residual unbalance is calculated according to the formula. The balancing method and standard residual unbalance are shown in Table 1 below:

[0081] Table 1: Implementation process record

[0082]

[0083]

[0084] According to the determined balancing method and standard residual unbalance, the unbalance of each part is controlled within the standard residual unbalance requirement, and the direction and size are recorded. The final residual unbalance is recorded in Table 1.

[0085] Taking the gear shaft as the positioning, according to the principle of minimum synthetic unbalance, the assembly angle of the corresponding remaining unbalance of each part is calculated. The assembly angle of each part can be calculated according to the optimization algorithm, and its specific angle is shown in Table 1 above.

[0086] The assembly accuracy of each part's runout in each direction must be strictly controlled according to the assembly accuracy. The specific assembly requirements are as follows: Figure 2 shown.

[0087] The present invention controls the angle of parts assembly so that the initial unbalance of the combined rotor is within a controllable range, and can reduce the weight removal when performing final residual unbalance control, thereby improving efficiency. At the same time, it also avoids the randomness of random assembly and avoids repeated assembly due to excessive weight removal, thereby effectively solving the problem of transcritical vibration and improving the product qualification rate.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling the initial unbalance of a combined rotor, characterized in that: The following steps are involved: S1, respectively determining a balancing method for correcting each part of the combined rotor; S2. Calculate the standard residual unbalance of each part according to the balancing method corresponding to the part; S3, performing balance correction on each part respectively until the final residual unbalance of the part approaches or reaches the standard residual unbalance, and recording the value and position direction of the final residual unbalance of the part; S4, calculating the assembly angle of the part according to the value and position direction of the final remaining unbalance; S5, assembling the parts into a combined rotor according to the assembly angle; S6. Performing an initial unbalance detection on the combined rotor and correcting a final remaining unbalance of the combined rotor.

2. The method for controlling the initial unbalance of a combined rotor according to claim 1, characterized in that: In step S1, the method for determining the balancing mode of the part is: Determine the balancing method according to the ratio of the diameter D to the thickness B of the part; When D / B ≥ 5, the parts are corrected by static balancing; When D / B<5, the parts are corrected by dynamic balancing.

3. A method for controlling the initial unbalance of a combined rotor according to claim 2, characterized in that: In step S2, the standard residual unbalance of the part corrected by the static balancing method is calculated by the following formula, specifically: Among them, m per is the allowable residual unbalanced mass, in g; m is the mass of the balanced part, in kg; G is the balancing accuracy, in mm / s; n is the maximum continuous operating speed, in r / min; r is the radius where the residual unbalance is located, in mm.

4. A method for controlling the initial unbalance of a combined rotor according to claim 2, characterized in that: In step S2, the standard residual unbalance of the part corrected by the dynamic balancing method is calculated by the following formula, specifically: Among them, U per is the maximum allowable residual unbalance on each plane, in g.mm; W is the static load of a single support journal, in N; n is the maximum continuous operating speed, in r / min.

5. The method for controlling the initial unbalance of a combined rotor according to claim 1, characterized in that: In step S4, the assembly angle of the parts is determined by the minimum value of the combined unbalance, which is: Among them, U x It is the objective function of decomposing all unbalanced quantities into components on the X-axis of the projection plane; U y It is the objective function that decomposes all unbalanced quantities into components on the Y-axis of the projection plane.

6. A method for controlling the initial unbalance of a combined rotor according to claim 5, characterized in that: The objective function U x for: Among them, U i is the unbalance value of the i-th part; α i is the position direction of the unbalance of the i-th part.

7. The method for controlling the initial unbalance of a combined rotor according to claim 5, characterized in that: The objective function U y for: Among them, U i is the unbalance value of the i-th part; α i is the position direction of the unbalance of the i-th part.

8. The method for controlling the initial unbalance of a combined rotor according to claim 1, characterized in that: In step S5, the assembly method of assembling the parts into the combined rotor is: During the assembly process of each part, the axial runout and radial runout range of each part on the axis of the combined rotor is ≤0.01mm.

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