A nested counterweight square balance built-in mechanical online dynamic balancing device

Abstract

The application discloses a nested counterweight square balance built-in mechanical online dynamic balancing device, belonging to the field of online dynamic balancing of super-speed main shafts, which comprises a driving transmission mechanism arranged in an outer driving cavity, wherein the driving transmission mechanism comprises two DC motors, the DC motors are fixedly connected with shaft couplings through reducers, the shaft couplings are matched with inner gears, the inner gears are connected with outer gears and inner-outer layer counterweight supports, the inner-outer layer counterweight supports are connected with dynamic balancing counterweights, the inner-outer layer counterweight supports and stepped mandrels form a nested structure and are matched with two groups of rolling bearings; the application can realize real-time feedback of the positions of the counterweights, solve the problem of dynamic balance head imbalance and improve the stability and precision of the balancing process.

Description

Technical Field

[0001] This invention relates to the field of rotating machinery spindle balancing technology, specifically to a nested counterweight torque balancing built-in mechanical online dynamic balancing device. Background Technology

[0002] Rotating machinery is widely used in energy, chemical, manufacturing equipment, and defense industries, such as steam turbines, compressors, machine tool spindles, and aero engines. During the operation of rotating machinery, problems such as mass eccentricity, structural asymmetry, installation errors, and wear on the spindle can disrupt its operation and cause vibrations in the rotor system. Torsional vibration and rotational imbalance are particularly prominent in rotating machines, including drive shafts, because they not only hinder the operation of the rotating machine system but can also damage the actual structure and components that make up the rotating machine system.

[0003] Based on the characteristics of rotor imbalance, it can be divided into initial imbalance, gradual imbalance, and sudden imbalance. First, as the rotational speed increases, even initially negligible imbalances can affect the spindle's operating state and interfere with its normal operation, thus placing higher demands on the precision of dynamic balancing. Second, under high-speed, long-term operation, the spindle inevitably develops gradual imbalances due to wear, plastic deformation, and material corrosion. Third, large imbalances can occur during spindle operation due to sudden events. Removing these imbalances usually requires disassembling and reassembling the rotor system and performing offline dynamic balancing on the spindle using a dynamic balancing machine. This consumes significant resources, and new imbalances can arise during disassembly and reassembly due to assembly errors. Therefore, the theoretical research and development of online dynamic balancing equipment have become urgent problems to be solved.

[0004] The motor-driven online dynamic balancing device uses a motor to drive the counterweights. During the spindle's operation, the combined force of the two counterweights cancels out the spindle's own imbalance, achieving online balancing. Currently, the widely adopted non-nested double-counterweight balancing head structure (Publication No.: CN104999330A, titled: A spindle-embedded mechanical online dynamic balancing device; Publication No.: CN115716138A, titled: An embedded mechanical online dynamic balancing device with a counterweight position closed loop) features a mass adjustment block and counterweights arranged side-by-side along the axial direction. This structure is beneficial for calculating the counterweight mass, but because the balancing forces generated by the two counterweights are not in the same plane, an unbalanced torque that cannot be eliminated is generated. This unbalanced torque causes an imbalance within the device itself, severely reducing the overall accuracy of the balancing device. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a nested counterweight torque balancing built-in mechanical online dynamic balancing device, which can provide real-time feedback on the position of the counterweight, improve positioning accuracy, overcome the problem of torque imbalance of non-nested dynamic balancing heads, and improve the stability and balancing efficiency of the balancing process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A nested counterweight torque balancing built-in mechanical online dynamic balancing device includes an outer drive cavity 1, a transmission cavity 2, and a counterweight shaft system 3 arranged sequentially.

[0008] The outer drive cavity 1 contains a centrally symmetrical closed-loop drive mechanism to form a symmetrical power output. The closed-loop drive mechanism includes a symmetrically arranged DC motor 6 with an encoder, which is fixed on a reduction gearbox 8. The power output end of the DC motor 6 is connected to the internal gear 10 via the reduction gearbox 8 and a coupling 9. The reduction gearbox 8 is connected to the motor connecting seat 7. A mass compensation block 11 is connected to the shorter coupling 9.

[0009] The transmission cavity 2 contains a centrally symmetrical internal gear meshing mechanism, forming a symmetrical transmission structure. The transmission structure includes a first external gear 13 and a second external gear 14 that mesh with the two internal gears 10. The second external gear 14 is connected to the inner counterweight support 21, the first external gear 13 is connected to the outer end cover 23, and the outer end cover 23 is connected to the outer counterweight support 22.

[0010] The aforementioned counterweight shaft system 3 contains nested counterweights, including a stepped spindle 15. The stepped spindle 15 is supported within an inner counterweight support 21 via a first bearing 16 and a second bearing 18. An inner end cap 24 is connected to the end of the inner counterweight support 21, and the inner end cap 24 is pressed against the second bearing 18. The inner counterweight support 21 is connected to an outer counterweight support 22 via a third bearing 19. The end of the outer counterweight support 22 is engaged with the stepped spindle 15 via a fourth bearing 20. An end cap 4 is connected to the end of the stepped spindle 15, and the end cap 4 is in contact with the fourth bearing 20. An inner counterweight 25 and an inner counterweight balance block 26 are connected to the inner counterweight support 21, and an outer counterweight 27 and an outer counterweight balance block 28 are connected to the outer counterweight support 22.

[0011] The internal gear 10, the first external gear 13, and the second external gear 14 form a multi-stage reduction gearing system via the reduction gearbox 8 and are self-locking.

[0012] The drive motor 6 can achieve position closed loop.

[0013] The gearbox 8 and coupling 9 are interference fits, and the coupling 9 and internal gear 10 are interference fits, with no clearance at the mating end faces.

[0014] The outer drive cavity 1 and the stepped mandrel 15 are interference fit.

[0015] The DC motor 6, the gearbox 8, the internal gear 10, the first external gear 13, and the second external gear 14 together form a drive mechanism with a reduction ratio of 1470.

[0016] The inner counterweight 25, outer counterweight 27, inner counterweight balance block 26, and outer counterweight balance block 28 are made of tungsten alloy.

[0017] The inner counterweight 25 and inner counterweight balance block 26, the outer counterweight 27 and outer counterweight balance block 28 are nested structures with the same length. The inner counterweight 25 has an angle of 180° and the outer counterweight 27 has an angle of 75.046°.

[0018] The transmission ratio between DC motor 6 and outer counterweight 27 and inner counterweight 25 is:

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention employs a double-layer nested balancing system, eliminating the problem of torque imbalance inherent in ordinary mechanical balancing heads. Each layer of counterweight is equipped with a corresponding counterweight balance block, eliminating force imbalance caused by bolt connections and different mass radii. The use of an coded motor allows for stable and controllable motor position and speed through PWM and PID control methods, avoiding "misalignment" problems and improving balancing efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the outer driving cavity portion of the present invention.

[0023] Figure 3 This is a schematic diagram of the transmission structure of the present invention.

[0024] Figure 4 This is a schematic diagram of the inner and outer layer shaft system support of the present invention.

[0025] Figure 5 This is a schematic diagram of the counterweight distribution according to the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0027] Reference Figure 1A nested counterweight torque balancing built-in mechanical online dynamic balancing device includes an outer drive cavity 1, a transmission cavity 2, and a counterweight shaft system 3 arranged sequentially. The entire device has an end cover 4 at the head and an electromagnetic slip ring 5 at the tail and the connection point with the main shaft. The electromagnetic slip ring 5 leads out the device wiring.

[0028] Reference Figure 2 The outer drive cavity 1 contains a closed-loop drive mechanism that is symmetrically positioned, forming a symmetrical power output. The closed-loop drive mechanism includes a DC motor 6 with an encoder that is symmetrically arranged. The DC motor 6 is fixed on the gearbox 8. The power output end of the DC motor 6 is connected to the internal gear 10 via the gearbox 8 and the coupling 9. The gearbox 8 is connected to the motor connecting seat 7. A mass compensation block 11 is connected to the shorter coupling 9.

[0029] Reference Figure 3 , Figure 4 The transmission cavity 2 contains a centrally symmetrical internal gear meshing mechanism, forming a symmetrical transmission structure. The transmission structure includes a first external gear 13 and a second external gear 14 that mesh with the two internal gears 10. The second external gear 14 is connected to the inner counterweight support 21, the first external gear 13 is connected to the outer end cover 23, and the outer end cover 23 is connected to the outer counterweight support 22.

[0030] Reference Figure 4 , Figure 5 The balance weight shaft system 3 contains nested counterweight balance weights, including a stepped spindle 15. The stepped spindle 15 is supported in the inner counterweight support 21 by a first bearing 16 and a second bearing 18. The end of the inner counterweight support 21 is bolted to an inner end cap 24, which is pressed against the second bearing 18. The inner counterweight support 21 is connected to an outer counterweight support 22 by a third bearing 19. The end of the outer counterweight support 22 is connected to the stepped spindle 15 by a fourth bearing 20. The end of the stepped spindle 15 is connected to an end cap 4, which is in contact with the fourth bearing 20. The inner counterweight support 21 is connected to an inner counterweight 25 and an inner counterweight balance weight 26, and the outer counterweight support 22 is connected to an outer counterweight 27 and an outer counterweight balance weight 28.

[0031] Reference Figure 2 and Figure 3 The internal gear 10, the first external gear 13, the second external gear 14, and the gearbox 8 form a multi-stage reduction gearing system and are self-locking.

[0032] The drive motor 6 can achieve position closed loop.

[0033] The gearbox 8 and coupling 9 are interference fits, and the coupling 9 and internal gear 10 are interference fits, with no clearance at the mating end faces.

[0034] The outer drive cavity 1 and the stepped mandrel 15 are interference fit.

[0035] The DC motor 6, the gearbox 8, the internal gear 10, the first external gear 13, and the second external gear 14 together form a drive mechanism with a reduction ratio of 1470.

[0036] Reference Figure 4 The inner counterweight 25, outer counterweight 27, inner counterweight balance block 26, and outer counterweight balance block 28 are made of tungsten alloy.

[0037] Reference Figure 5 The inner counterweight 25 and inner counterweight balance block 26, the outer counterweight 27 and outer counterweight balance block 28 are nested structures with the same length. The angle of the inner counterweight 25 is 180° and the angle of the outer counterweight 27 is 75.046°.

[0038] Reference Figure 2 and Figure 3 The transmission ratio between DC motor 6 and outer counterweight 27 and inner counterweight 25 is:

[0039] The DC motor 6 receives and outputs signals from the outside via a high-speed slip ring.

[0040] The working principle of this invention is as follows:

[0041] The nested counterweight torque balancing device is embedded in the inner hole of the spindle through an overfitting method. The electromagnetic slip ring 5 is locked to the spindle with bolts. After the power is turned on, the encoder records the current position of the balance block. When the spindle imbalance is detected, the spindle vibration signal is measured and calculated to extract the spindle imbalance amount and phase. The DC motor 6 is then driven to drive the inner and outer counterweight blocks for trial weighing. The control system records the position information of the inner counterweight 25 and the outer counterweight 27. The corresponding algorithm finds the position that minimizes the imbalance vibration vector and controls the inner counterweight balance block 26 and the outer counterweight balance block 28 to move to that position. Since the nested counterweight system itself does not have torque imbalance, the control system with position closed loop can more accurately control the position of the inner counterweight balance block 26 and the outer counterweight balance block 28, thereby avoiding the "misalignment" problem, improving the stability of the balancing process, and improving the balancing efficiency.

Claims

1. A nested counterweight torque balancing built-in mechanical online dynamic balancing device, characterized in that: It includes an outer drive chamber (1), a transmission chamber (2), and a balance weight shaft system (3) arranged sequentially: The outer drive cavity (1) contains a closed-loop drive mechanism with a centrally symmetrical position, forming a symmetrical power output. The closed-loop drive mechanism includes symmetrically arranged DC motors (6) with encoders. The DC motors (6) are fixed on the gearbox (8). The power output end of the DC motors (6) is connected to the internal gear (10) via the gearbox (8) and the coupling (9). The gearbox (8) is fixed on the motor connecting seat (7). A mass compensation block (11) is connected to the shorter coupling (9). The transmission cavity (2) contains a centrally symmetrical internal gear meshing mechanism, forming a symmetrical transmission structure; the transmission structure includes a first external gear (13) and a second external gear (14) that mesh with two internal gears (10), the second external gear (14) is connected to the inner counterweight support (21), the first external gear (13) is connected to the outer end cover (23), and the outer end cover (23) is connected to the outer counterweight support (22); The balance weight shaft system (3) contains nested counterweight balance weights, including a stepped spindle (15). The stepped spindle (15) is supported in the inner counterweight support (21) by a first bearing (16) and a second bearing (18). The end of the inner counterweight support (21) is connected to an inner end cap (24), which is pressed against the second bearing (18). The inner counterweight support (21) is connected to the outer counterweight support by a third bearing (19). The outer counterweight support (22) is connected to the fourth bearing (20) and the stepped spindle (15) at the end. The end of the stepped spindle (15) is connected to the end cap (4), and the end cap (4) is in contact with the fourth bearing (20). The inner counterweight support (21) is connected to the inner counterweight (25) and the inner counterweight balance block (26). The outer counterweight support (22) is connected to the outer counterweight (27) and the outer counterweight balance block (28).

2. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The internal gear (10), the first external gear (13), and the second external gear (14) form a multi-stage reduction gearing system via the gearbox (8) and are self-locking.

3. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The DC motor (6) described above can achieve position closed loop.

4. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The gearbox (8) and coupling (9) are interference fits, and the coupling (9) and internal gear (10) are interference fits, with no clearance at the mating end faces.

5. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The outer drive cavity (1) and the stepped mandrel (15) are interference fit.

6. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The DC motor (6), gearbox (8), internal gear (10), first external gear (13), and second external gear (14) together form a drive mechanism with a reduction ratio of 1470.

7. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The inner counterweight (25), outer counterweight (27), inner counterweight balance block (26), and outer counterweight balance block (28) are made of tungsten alloy.

8. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The inner counterweight (25) and inner counterweight balance block (26), the outer counterweight (27) and outer counterweight balance block (28) are nested structures with the same length. The inner counterweight (25) has an angle of 180° and the outer counterweight (27) has an angle of 75.046°.

9. The nested counterweight torque balancing built-in mechanical online dynamic balancing device according to claim 1, characterized in that: The transmission ratio between the DC motor (6) and the outer counterweight (27) and the inner counterweight (25) is:

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