Machining method for improving dynamic balance of impeller by transferring center line of impeller and impeller

Abstract

The machining method for improving the dynamic balance of the impeller by transferring the center line of the impeller comprises the following steps that the dynamic unbalance amount of the impeller is obtained, and the heavy end of the impeller is marked; calculating the offset C of the center line of the impeller; the impeller is placed in the center of a lathe workbench, the end marked with the impeller weight is placed at a clamping jaw, the outer circle of the impeller is aligned, and the center of the impeller is made to coincide with the original point of the lathe workbench; the heavy end of the impeller is translated towards the outer side of a lathe workbench through a clamping jaw, and translation is conducted according to the calculated offset C of the center line of the impeller; and all the machined surfaces of the impeller are turned, and the dynamic unbalance amount of the impeller is removed. The center line of the impeller is transferred, the center original point of the workbench becomes the new center line original point of the impeller, during turning, more metal materials are turned off on all the machined surfaces of the heavy side of the impeller, and therefore the purpose of improving the balance of the impeller is achieved, efficiency is high, precision is high, and operation is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of impeller processing, and specifically relates to a processing method and an impeller for improving the dynamic balance of an impeller by shifting the center line of the impeller. Background Art

[0002] The nuclear main pump is the heart of the nuclear power unit and the key to controlling the water circulation of nuclear power operation. The nuclear power unit has a large flow rate, and the impeller of the nuclear main pump is a large casting. Due to the large casting volume, flow channel displacement or casting deviation will occur during the casting process, resulting in uneven casting quality. This will cause the dynamic imbalance of the impeller to be too large, sometimes up to several kilograms, which will cause the rotor to run unstably, and the unit will cause vibration, noise and other performance indicators to fail to meet the standards, seriously affecting the safety and reliability of the unit operation, and causing mechanical failure. For the nuclear main pump, the safety and reliability of the unit is the primary task to ensure the safety of people's lives, so the dynamic imbalance must be removed to ensure the safe and reliable operation of the unit. The traditional method for this large weight imbalance is to lift the heavy side of the workpiece on a vertical lathe, cut the raised side cover plate, and remove the weight by measuring the weight on a balance. Under normal circumstances, it is necessary to repeatedly turn and balance several times to reach the standard value of the impeller dynamic balance. On the one hand, this processing method causes uneven cover plate thickness, poor surface quality, and even causes the cover plate thickness to be less than the designed size, affecting the strength of the impeller, causing non-conformity or impeller scrapping, resulting in significant economic losses; on the other hand, repeated operations, low efficiency, and long processing cycles increase the operator's labor intensity. Summary of the invention

[0003] In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller. The method of the present invention is highly efficient and easy to operate. By shifting the center line of the impeller, more metal material is removed from all the processing surfaces on the heavy side of the impeller to achieve the purpose of improving the balance of the impeller.

[0004] To achieve the above-mentioned object, the first aspect of the present invention provides a processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller, comprising the following steps:

[0005] Marking: Obtain the dynamic unbalance of the impeller and mark the heavy end of the impeller;

[0006] Calculate the offset: Calculate the impeller centerline offset C based on the obtained dynamic unbalance of the impeller;

[0007] Transfer the impeller centerline: Place the impeller at the center of the lathe worktable, place the end marked with the impeller weight on the clamp, align the outer circle of the impeller so that the origin of the impeller centerline coincides with the origin of the lathe worktable; then use the clamp to translate one end of the impeller weight toward the outside of the lathe worktable according to the calculated impeller centerline offset C;

[0008] Turning: Start the lathe and turn all the machining surfaces of the impeller to remove the dynamic imbalance of the impeller. At this time, the center of the lathe worktable becomes the new center of the impeller, completing the transfer of the impeller centerline.

[0009] Furthermore, the above-mentioned processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller also includes: performing a rough imbalance detection on the impeller, setting a standard value of the impeller dynamic imbalance to A, and an actual measured value of the impeller dynamic imbalance to G. If G is greater than A, the imbalance is removed by shifting the impeller center line; if G is less than or equal to A, there is no need to remove the imbalance.

[0010] Furthermore, in the above-mentioned processing method for improving the dynamic balance of an impeller by shifting the center line of an impeller, the impeller center line offset C is calculated according to the formula (1) using the measured value G of the impeller dynamic imbalance and the impeller offset ratio E:

[0011] C=G / E (1)

[0012] Where, C: impeller centerline offset, unit: mm;

[0013] G: The measured value of the impeller dynamic unbalance, unit: g;

[0014] E: Impeller offset ratio, unit: g / mm.

[0015] The impeller offset ratio E is the amount of impeller imbalance removed for every 1 mm offset of the impeller centerline.

[0016] Furthermore, in the above-mentioned processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller, in the step of shifting the center line of the impeller, the outer circle of the impeller is aligned so that the origin of the impeller center line coincides with the origin of the lathe worktable. Specifically, the impeller is placed in the center of the lathe worktable, the end marked with the weight of the impeller is placed on the clamp, the outer circle of the impeller is aligned with a dial indicator or a micrometer, and the position of the impeller is adjusted with the clamp so that the origin of the impeller center line coincides with the origin of the worktable.

[0017] Furthermore, the above-mentioned processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller also includes an inspection step, specifically: translating one end of the impeller weight toward the outside of the lathe worktable through the clamp, translating according to the calculated impeller centerline offset C, and aligning the impeller position after translation based on the center of the lathe worktable with a dial indicator or a micrometer until it is determined that the meter value of one end of the impeller weight is twice the offset C, that is, the inspection is qualified.

[0018] A second aspect of the present invention provides an impeller, wherein the processing method of the impeller includes the above-mentioned processing method for improving the dynamic balance of the impeller by shifting the center line of the impeller.

[0019] The beneficial effects of the present invention are:

[0020] The present invention transfers the center line of the impeller, and the center origin of the workbench becomes the new center line origin of the impeller. During turning, more metal material is removed from all the processing surfaces on the heavy side of the impeller, thereby achieving the purpose of improving the balance of the impeller, and the operation is simple. The method provided by the present invention is to remove more metal material from all the processing surfaces on the heavy side of the impeller, which will not cause uneven thickness of the cover plate and poor surface quality of the impeller, will not affect the design size and strength of the cover plate thickness, and ensure the quality of the impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a working principle diagram of the impeller centerline offset of the present invention. DETAILED DESCRIPTION

[0022] In order to better understand the above-mentioned technical scheme, the technical scheme of the embodiments of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the embodiments of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0023] A first aspect of an embodiment of the present invention provides a processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller, comprising the following steps:

[0024] Marking: Obtain the dynamic unbalance of the impeller and mark the heavy end of the impeller;

[0025] Calculate the offset: Calculate the impeller centerline offset C based on the obtained dynamic unbalance of the impeller;

[0026] Transfer the impeller centerline: Place the impeller on the center of the lathe worktable, place the end marked with the weight of the impeller on the clamp, align the outer circle of the impeller so that the origin of the impeller centerline coincides with the origin of the lathe worktable; then use the clamp to translate the end of the impeller marked with the weight toward the outside of the lathe worktable according to the calculated impeller centerline offset C;

[0027] Turning: Start the lathe and turn all the machining surfaces of the impeller to remove the dynamic imbalance of the impeller. At this time, the center of the lathe worktable becomes the new center of the impeller, completing the transfer of the impeller centerline.

[0028] The method provided by the present invention, by marking the heavy end of the impeller, can easily find the outward moving end when the impeller is installed on the lathe workbench, and the worker has a clear operating direction, so that the imbalance of the heavy end can be accurately removed, and the wrong processing direction will not occur. The present invention places the end marked with the weight of the impeller on the clamping jaw, which is convenient for adjusting the position of the impeller with the clamping jaw. It is simple, clear and easy to operate. The present invention obtains the impeller centerline offset C by calculation, and the data is clear and the operability is strong, so the impeller can be quickly translated. After the translation is qualified, all the processing surfaces of the impeller are turned. Since the impeller is offset, more metal is removed on the heavy side, thereby removing the dynamic imbalance of the impeller. At this time, the center origin of the workbench becomes the new centerline origin of the workpiece, and the transfer of the impeller centerline is completed. The method provided by the present invention eliminates the need for heavy cutting of the cover plate, thus ensuring the machining accuracy of the workpiece, saving the machining cycle caused by repeated deweighting and balancing operations, avoiding the risk of the cover plate failing to meet the designed thickness due to deweighting, thereby reducing the strength of the impeller, ensuring product quality, and increasing the safety and reliability of the impeller operation.

[0029] In some feasible embodiments, the processing method further includes: performing a rough imbalance detection on the impeller, setting the standard value of the impeller dynamic imbalance to A, and the measured value of the impeller dynamic imbalance to G. If G is greater than A, the imbalance is removed by shifting the center line of the impeller; if G is less than or equal to A, there is no need to remove the imbalance.

[0030] The present invention performs a rough imbalance detection before the impeller is finely processed, with the purpose of detecting the dynamic imbalance of the impeller as early as possible and removing the imbalance as early as possible, so as to avoid a large dynamic imbalance during the fine balancing of the impeller, the removal of a large amount of metal resulting in deformation, or the removal of a large size resulting in the production of defective products, causing economic losses and affecting the construction period.

[0031] In some feasible implementations, further, the impeller centerline offset C is calculated according to formula (1) using the measured value G of the impeller dynamic unbalance and the impeller offset ratio E:

[0032] C=G / E (1)

[0033] Where, C: impeller centerline offset, unit: mm;

[0034] G: The measured value of the impeller dynamic unbalance, unit: g;

[0035] E: Impeller offset ratio, unit: g / mm.

[0036] The impeller offset ratio E refers to the amount of impeller imbalance removed for every 1 mm offset of the impeller centerline. For example, for a certain impeller, the impeller offset ratio E = 2400g / mm, which means that for every 1 mm offset of the impeller centerline, 2400g of impeller imbalance can be removed.

[0037] Here, the impeller offset ratio E=2400g / mm is only used as an example to enhance understanding. This value may vary depending on the shape and size of the impeller. A person skilled in the art can calculate the impeller offset ratio E based on the metal properties and the shape of the impeller using common knowledge, or can measure the impeller offset ratio E of a specific type / model of workpiece based on a processing method for improving the dynamic balance of the impeller by shifting the impeller centerline.

[0038] In some feasible embodiments, further, in the step of transferring the impeller centerline, the outer circle of the impeller is aligned so that the origin of the impeller centerline coincides with the origin of the lathe worktable, specifically: the impeller is placed in the center of the lathe worktable, the end marked with the impeller weight is placed on the clamp, the outer circle of the impeller is aligned with a dial indicator or a micrometer, and the position of the impeller is adjusted with the clamp so that the origin of the impeller centerline coincides with the origin of the worktable.

[0039] The present invention uses a dial indicator or a micrometer for alignment, the reading is accurate to 0.01mm or 0.001mm, the position is accurate, and the fit between the centerline origin of the workpiece and the origin of the worktable is more accurate. The meter is set outside the outer circle, which is convenient for the operator to observe and is not prone to observation errors.

[0040] In some feasible embodiments, the processing method further includes an inspection step, specifically: translating one end of the impeller weight toward the outside of the lathe worktable through the clamp, translating according to the calculated impeller centerline offset C, and aligning the impeller position after translation based on the center of the lathe worktable with a dial indicator or a micrometer until it is determined that the meter value of one end of the impeller weight is twice the offset C, that is, the inspection is qualified.

[0041] The present invention determines that the meter value at one end of the impeller weight is twice the offset C through a dial gauge or a micrometer, and the operator can operate it simply, reliably and quickly.

[0042] The present invention provides a processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller. The working principle is as follows: Figure 1As shown. The figure shows the outer circle of the impeller ring used for impeller alignment, XOY is the lathe table coordinate system, and O is the coordinate origin. C is the impeller centerline offset, X1 and X2 are the intersection points of the impeller ring outer circle and the X-axis (the origin of the impeller centerline coincides with the coordinate point), Y1 and Y2 are the intersection points of the impeller outer circle and the Y-axis (the origin of the impeller centerline coincides with the coordinate point), O" is the origin of the impeller centerline after the impeller centerline is offset by C, X1" and X2" are the intersection points of the impeller ring outer circle and the X-axis after the impeller centerline is offset by C, and Y1" and Y2" are the intersection points of the impeller ring outer circle and the Y-axis after the impeller centerline is offset by C. First, place the impeller The impeller is placed at the origin of the coordinate system, that is, the origin of the impeller centerline coincides with the origin of the lathe table, and the outer circle of the impeller mouth ring intersects with the coordinate system to form X1, X2, Y1, and Y2. Then the impeller is translated to the side marked with weight according to the calculated impeller centerline offset C. The impeller center moves to the O" position, X1 moves to X1", X2 moves to X2", Y1 moves to Y1", and Y2 moves to Y2". The position of the impeller after movement is aligned based on the center of the lathe table, such as Figure 1 As shown: the Y-axis direction has the same dial value, the X-axis direction is set to 0 at X1", and the X2" direction dial value is 2C, so the offset C is moved according to the calculated value. Then clamp the impeller and turn all the machined surfaces of the impeller, so that the center origin of the lathe table becomes the new center line origin of the impeller, completing the goal of transferring the impeller center line.

[0043] Example 1

[0044] A processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller comprises the following steps:

[0045] Step 1: Obtain the dynamic imbalance of the impeller

[0046] Use a dynamic balancing machine to perform rough imbalance detection on the impeller. Set the standard value of the impeller dynamic imbalance to A, and the measured value of the impeller dynamic imbalance to G. If G is greater than A, the imbalance is removed by shifting the impeller centerline. If G is less than or equal to A, there is no need to remove the imbalance.

[0047] As an example, in this embodiment, a certain type of nuclear main pump is the core equipment of a nuclear power unit, used for controlling water circulation in nuclear power operation. The impeller of the nuclear main pump is a large casting, and its impeller material is CA6NM, which is an ASTM material. According to the standard, the standard value of the impeller dynamic unbalance is set to A=300g, and a dynamic balancing machine is used to perform a rough unbalance detection on the impeller. The measured value of the impeller dynamic unbalance is G=600g. If G is greater than A, the unbalance needs to be removed.

[0048] Step 2: Marking

[0049] Obtain the dynamic unbalance of the impeller and mark it at the heavy end of the impeller.

[0050] As an exemplary explanation, in this embodiment, according to the detection result of step 1, the measured value G of the impeller dynamic unbalance is greater than A, such as Figure 1 As shown, a mark is made on the heavy end of the impeller. As an example, the word "heavy" is written on the heavy end of the impeller as a mark.

[0051] Step 3: Calculate the offset C

[0052] The impeller centerline offset C is calculated based on the obtained dynamic unbalance of the impeller.

[0053] 1) Obtain the impeller offset ratio E. According to the three-dimensional model, the impeller offset ratio E = 2400g / mm is calculated. That is, every 1mm offset of the impeller centerline can remove 2400g of impeller imbalance.

[0054] 2) Calculate the impeller centerline offset C according to formula (1):

[0055] C=G / E (1)

[0056] Where; C: impeller centerline offset, unit: mm;

[0057] G: The measured value of the impeller dynamic unbalance, unit: g;

[0058] E: Impeller offset ratio, unit: g / mm.

[0059] As an exemplary explanation, in this embodiment, the dynamic unbalance amount at the suction end of the impeller is used as a reference to calculate the impeller centerline offset C. In this embodiment, the impeller material of the nuclear main pump is CA6NM, which is an ASTM material.

[0060] Step 1: Obtain the measured values ​​of the impeller dynamic unbalance G = 600g, E = 2400g / mm. According to formula (1), the impeller centerline offset C = 600 / 2400 = 0.25mm.

[0061] Step 4: Transfer the impeller centerline

[0062] 1) Place the impeller in the center of the lathe worktable, place the end marked with the impeller weight on the clamping jaw, align the outer circle of the impeller so that the origin of the impeller centerline coincides with the origin of the lathe worktable.

[0063] As an exemplary explanation, in this embodiment, the impeller is placed at the center of the lathe worktable, the end of the impeller marked "heavy" is placed on the clamp, the outer circle of the impeller is aligned with a dial indicator or a micrometer, and the position of the impeller is adjusted with the clamp so that the origin of the impeller centerline coincides with the origin of the worktable.

[0064] 2) Use the clamp to translate the heavy end of the impeller toward the outside of the lathe worktable, and translate it according to the impeller centerline offset C calculated in step 3.

[0065] As an exemplary explanation, in this embodiment, if Figure 1 As shown, the heavy end of the impeller is translated toward the outside of the lathe worktable through the clamping jaws, that is, the impeller is translated toward the side marked with "heavy", and the translation amount is C = 0.25 mm.

[0066] Step 5: Check

[0067] The position of the impeller after translation is checked based on the center of the lathe table, and is aligned using a dial indicator or micrometer until the dial value at the heavy end of the impeller is determined to be twice the offset C, which means the inspection is qualified.

[0068] As an exemplary explanation, in this embodiment, if Figure 1 As shown, after the impeller is translated by C=0.25mm, the position of the impeller after translation is aligned by dialing. The center of the impeller moves to the O" position, X1 moves to X1", X2 moves to X2", Y1 moves to Y1", and Y2 moves to Y2". With the center of the lathe table as the center, use a dial indicator or micrometer to align the Y-axis direction. The dial value is the same, and the X-axis direction is set to 0 at X1", then the X2" direction needle value is 2C (i.e. 0.5mm). In this way, the offset C is moved according to the calculated value.

[0069] Step 6: Turning

[0070] Start the lathe and turn all the machining surfaces of the impeller to remove the dynamic imbalance of the impeller. In this way, the center of the lathe worktable becomes the new center of the impeller, realizing the transfer of the impeller centerline.

[0071] As an exemplary explanation, in this embodiment, if Figure 1 As shown, all the machined surfaces of the impeller are turned, that is, the imbalance in the range of Y2"-X2"-Y1"-X2 is removed.

[0072] According to the above-mentioned processing method for improving the dynamic balance of the impeller by shifting the center line of the impeller, more than 50 impellers have been operated to offset the center line in actual production, which greatly improved the balance state of the impeller. In the subsequent fine balancing operation, the goal of fine balancing of the impeller can be achieved by drilling several small-sized blind holes at a specific position of the workpiece, and there is no need to perform heavy cutting on the cover plate. This method ensures the processing accuracy of the workpiece, saves the processing cycle caused by repeated deweighting and balancing operations, avoids the risk of the impeller cover plate not meeting the designed thickness due to deweighting, thereby reducing the strength of the impeller, ensures product quality, and increases the safety and reliability of the impeller operation. The present invention achieves the purpose of improving the balance of the impeller by shifting the center line of the impeller and removing more metal materials from all the processing surfaces on the heavy side of the impeller.

[0073] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above are only preferred implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller, characterized in that: The processing method comprises the following steps: Marking: Obtain the dynamic unbalance of the impeller and mark the heavy end of the impeller; Calculate the offset: Calculate the impeller centerline offset C based on the obtained dynamic unbalance of the impeller; Transfer the impeller centerline: Place the impeller at the center of the lathe worktable, place the end marked with the impeller weight on the clamp, align the outer circle of the impeller so that the origin of the impeller centerline coincides with the origin of the lathe worktable; then use the clamp to translate one end of the impeller weight toward the outside of the lathe worktable according to the calculated impeller centerline offset C; Turning: Start the lathe and turn all the machining surfaces of the impeller to remove the dynamic imbalance of the impeller. At this time, the center of the lathe worktable becomes the new center of the impeller, completing the transfer of the impeller centerline.

2. A processing method for improving the dynamic balance of an impeller by shifting the center line of an impeller according to claim 1, characterized in that: The processing method also includes: performing a rough imbalance detection on the impeller, setting the standard value of the impeller dynamic imbalance to A, and the actual measured value of the impeller dynamic imbalance to G. If G is greater than A, the imbalance is removed by shifting the impeller center line. If G is less than or equal to A, there is no need to remove the imbalance.

3. A processing method for improving the dynamic balance of an impeller by shifting the center line of the impeller according to claim 2, characterized in that: The impeller centerline offset C is calculated using the measured value G of the impeller dynamic unbalance and the impeller offset ratio E according to formula (1): C=G / E (1) Where, C: impeller centerline offset, unit: mm; G: The measured value of the impeller dynamic unbalance, unit: g; E: Impeller offset ratio, unit: g / mm; The impeller offset ratio E is the amount of impeller imbalance removed for every 1 mm offset of the impeller centerline.

4. A processing method for improving the dynamic balance of an impeller by shifting the center line of an impeller according to claim 1, characterized in that: In the step of transferring the center line of the impeller, align the outer circle of the impeller so that the origin of the impeller center line coincides with the origin of the lathe worktable. Specifically, place the impeller in the center of the lathe worktable, place the end marked with the impeller weight on the clamp, use a dial indicator or micrometer to align the outer circle of the impeller, and use the clamp to adjust the position of the impeller so that the origin of the impeller center line coincides with the origin of the lathe worktable.

5. A processing method for improving the dynamic balance of an impeller by shifting the center line of an impeller according to claim 1, characterized in that: The processing method also includes an inspection step, specifically: using a clamp to translate one end of the impeller weight toward the outside of the lathe worktable, and translate according to the calculated impeller centerline offset C, and using a dial indicator or a micrometer to align the impeller position after translation based on the center of the lathe worktable until it is determined that the meter value of one end of the impeller weight is twice the offset C, which means the inspection is qualified.

6. An impeller, characterized in that: The impeller processing method includes the processing method for improving the dynamic balance of the impeller by shifting the impeller center line as described in any one of claims 1 to 5.

Images