Stabilizing structure for front bearing of steam turbine

Abstract

The utility model relates to the technical field of steam turbines, in particular to a stabilizing structure for a front bearing of a steam turbine. The stabilizing structure for the front bearing of the steam turbine is arranged between a bearing bush hoop and an upper bearing bush of the front bearing of the steam turbine and comprises an adjusting block, a positioning pin and a fastener, the adjusting block is installed on the bearing bush hoop of the front bearing of the steam turbine, a clamping groove is formed in the adjusting block, and a positioning hole and an installation hole are formed in the bottom of the clamping groove; the positioning pin is mounted on the bearing bush tightening hoop, and the positioning pin is configured to be matched with the positioning hole to position the mounting of the adjusting block; the fastener is configured to be matched with the mounting hole to mount the adjusting block on the bearing bush tightening hoop; wherein the pair of adjusting blocks are symmetrically arranged around the axis of the front bearing of the steam turbine, and the adjusting blocks are configured to be clamped with the bearing bush hoop through the clamping grooves and used for mechanically limiting the upper bearing bush. According to the stabilizing structure for the turbine front bearing, the stability of the turbine front bearing is improved, and safe, stable and long-period operation of a unit is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine technology, and specifically to a stabilizing structure for the front bearing of a steam turbine. Background Technology

[0002] In the field of thermal power generation, steam turbines are key equipment, and their operational stability is crucial to the security of power supply and the economic benefits of power plants. Among them, the radial bearings of steam turbines are the core components that support the turbine rotor and ensure its stable operation.

[0003] The existing turbine generator front bearing consists of upper and lower housing halves, support pads, and locating keys. Babbitt metal is installed inside the bearing housing, connected by tapered pins and bolts. Thermocouples are used as the bearing's metal temperature sensing element. The bearing is mounted on a spherical mount; this spherical fit allows the bearing bush to automatically adjust its position according to the rotor's deflection and tilt, ensuring optimal lubrication between the journal and the bearing bush.

[0004] The aforementioned turbine unit's front bearing theoretically possesses a certain degree of automatic adjustment capability; however, it experiences frequent problems during actual operation. Analysis of the bearing temperature curve reveals that the metal temperature at multiple measuring points on the lower bearing shell gradually increases over time, and the lower bearing shell metal temperature fluctuates with load changes, decreasing during load increases and increasing rapidly during load decreases. Particularly under low load conditions, the high-pressure cylinder's external steam supply flow is excessive, and the high-pressure rotor is relatively light, leading to changes in the high-pressure rotor's shaft trajectory. This alters the relative position of the front bearing shell and the high-pressure rotor, deteriorating the shell's self-aligning capability and accelerating the increase in bearing shell temperature.

[0005] Although existing technologies include drilling holes in the front bearing housing of steam turbine units and installing set screws to dynamically adjust the bearing position and reduce the difficulty of adjusting the bearing center, for example, Chinese patent document CN201339495Y discloses an improved steam turbine bearing alignment pad structure, the set screw method of adjusting the bearing is implemented during unit operation. This method is highly likely to cause the bearing to jam, resulting in a rapid increase in bearing temperature, sudden vibration, and irreversible serious failures, posing a significant safety risk. Summary of the Invention

[0006] Based on the above problems, the purpose of this utility model is to provide a stable structure for optimizing the front bearing of a steam turbine. By optimizing the design and installation of the anti-jump block of the bearing bush, the stability of the front bearing of the steam turbine is improved, ensuring the safe, stable and long-term operation of the unit.

[0007] To achieve the above objectives, this utility model proposes a stabilizing structure for a turbine front bearing, disposed between the bearing bush clamp and the upper bearing bush of the turbine front bearing, comprising:

[0008] An adjusting block is installed on the bearing bush clamp of the front bearing of the steam turbine. The adjusting block is provided with a slot, and the bottom of the slot is provided with a positioning hole and a mounting hole.

[0009] A locating pin is mounted on the bearing bush clamp and is configured to engage with a locating hole to position the adjusting block during installation.

[0010] And fasteners configured to mate with mounting holes to mount the adjusting block onto the bearing bush clamp;

[0011] Among them, a pair of adjusting blocks are symmetrically arranged around the axis of the front bearing of the turbine. The adjusting blocks are configured to engage with the bearing bush using a slot, which is used to mechanically limit the upper bearing bush.

[0012] When a steam turbine operates at high speed, factors such as rotor imbalance and steam pressure fluctuations can cause high-frequency vibration or displacement of the bearing bush. After the adjusting block engages tightly with the bearing bush via a slot, its top or side directly provides physical resistance to the upper bearing bush. When the turbine is running, if the upper bearing bush experiences upward, downward, or radial displacement due to rotor load or vibration, the adjusting block mechanically restricts its movement, ensuring the bearing bush remains in its designed position. The mechanical limiting function of the adjusting block controls the displacement of the upper bearing bush within a safe range, preventing abnormal friction between the bearing bush and the journal, thereby reducing wear, lowering vibration noise, and extending bearing life.

[0013] Preferably, an adjustment gap is provided between the adjustment block and the upper bearing bush, and an adjustment piece is provided within the adjustment gap.

[0014] Preferably, the groove and the bearing bush are in clearance fit.

[0015] Preferably, the card slot is a U-shaped slot, and the inner wall of the U-shaped slot is provided with anti-slip texture.

[0016] Preferably, the end of the mounting hole is provided with a countersunk plate, and the fastener is configured as an internal hex bolt that matches the mounting hole. The countersunk plate is constructed to accommodate the head of the internal hex bolt.

[0017] As a preferred option, the locating pin is a tapered pin.

[0018] Preferably, the tightening torque of the internal hex bolt is 100 N·m-120 N·m.

[0019] Preferably, the bottom of the card slot is provided with a pair of positioning holes, and the mounting hole is located between the pair of positioning holes.

[0020] Compared with existing technologies, the stabilization structure for the front bearing of a steam turbine provided by this utility model has the following substantial features and advancements: This stabilization structure for the front bearing of a steam turbine improves upon the existing anti-jump block of the bearing bush by replacing it with an adjusting block, and changes the installation position from both sides of the upper bearing bush to the bearing bush clamp. This allows the adjusting block to better withstand the effects of rotor disturbance forces and oil film pressure changes, preventing the bearing bush from tilting due to uneven stress, ensuring the stability of the steam turbine rotor shaft system center, improving the stability of the front bearing of the steam turbine, and guaranteeing the safe, stable, and long-term operation of the unit. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the assembly structure of a stabilizing structure for a steam turbine front bearing, according to an embodiment of this utility model.

[0022] Figure 2 This is a schematic diagram of the structure of the adjustment block in an embodiment of the present invention.

[0023] Figure 3 This is a cross-sectional view of the adjustment block in an embodiment of this utility model.

[0024] Attached reference numerals: 1. Upper bearing bush; 2. Bearing bush clamp; 3. Bearing bush anti-jump block installation position; 4. Adjusting block installation position; 5. Adjusting block; 51. Slot; 52. Mounting hole; 53. Positioning hole. Detailed Implementation

[0025] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0026] Existing anti-jump blocks for turbine bearings have defects in shape, size, and installation position, causing instability in the bearing position during operation. This leads to axial misalignment of the bearings during unit operation, resulting in changes in the turbine shaft center, uneven stress on the bearings, and consequently, severe excessive vibration of the turbine shaft system, high bearing temperature, rubbing between moving and stationary parts, and bearing wear and tear, among other problems, even forcing the unit to shut down. The stabilization structure for the turbine front bearing proposed in this utility model aims to improve the stability of the turbine front bearing by optimizing the design of the anti-jump block, ensuring safe, stable, and long-term operation of the unit.

[0027] like Figure 1 and Figure 2 As shown, a stabilizing structure for a turbine front bearing is disposed between the bearing bush clamp 2 and the upper bearing bush 1 of the turbine front bearing, comprising:

[0028] Adjusting block 5 is installed on the bearing bush clamp 2 of the front bearing of the steam turbine. Adjusting block 5 is provided with a groove 51, and the bottom of groove 51 is provided with a positioning hole 53 and a mounting hole 52.

[0029] The locating pin is installed on the bearing bush clamp 2 and is configured to cooperate with the locating hole 53 to position the installation of the adjusting block 5.

[0030] And fasteners, which are configured to mate with mounting holes 52, to mount the adjusting block 5 on the bearing bush clamp 2;

[0031] Among them, a pair of adjusting blocks 5 are symmetrically arranged around the axis of the front bearing of the turbine. The adjusting blocks 5 are configured to engage with the bearing bush clamp 2 using the slot 51, which is used to mechanically limit the upper bearing bush 1.

[0032] When the turbine is running, if the upper bearing 1 experiences upward, downward, or radial displacement due to rotor load or vibration, the adjusting block 5 will mechanically limit its movement, ensuring that the bearing remains in its designed position. The mechanical limiting of the adjusting block 5 can control the displacement of the upper bearing 1 within a safe range, avoiding abnormal friction between the bearing and the journal, thereby reducing wear, lowering vibration noise, and extending bearing life.

[0033] like Figure 2 As shown, a pair of positioning holes 53 are provided at the bottom of the slot 51, and the mounting hole 52 is located between the pair of positioning holes 53. Thus, during the operation of the steam turbine, when the bearing bush is subjected to complex loads from the rotor, the reaction force on the adjusting block 5 forms a stable force-bearing structure through the positioning holes 53 and the mounting hole 52, evenly distributing the force to the bearing bush clamp 2, avoiding local stress concentration, preventing the adjusting block 5 from deforming or loosening due to uneven force, and enhancing the load-bearing capacity and durability of the entire stable structure.

[0034] The number of mounting holes 52 can be selected appropriately based on the actual stress intensity. For example... Figure 2 As shown, a pair of mounting holes 52 are arranged between a pair of positioning holes 53, which helps to further improve the impact load resistance of the adjusting block 5.

[0035] Considering that the ideal clearance between the bearing and the rotor will vary due to factors such as temperature and load when the turbine is operating under different conditions, a clearance compensation design mechanism is added to the stabilizing structure used for the turbine's front bearing to ensure its stability. The specific design structure is as follows.

[0036] An adjustment gap is provided between the adjusting block 5 and the upper bearing 1. An adjusting slab is installed within the adjustment gap. By inserting adjusting slabs of different thicknesses into the adjustment gap, the clearance between the bearing and the rotor can be adjusted. For example, during the turbine start-up and preheating stage, the thickness of the adjusting slab can be increased to compensate for the clearance reduction caused by thermal expansion; during the stable operation stage, replacing the adjusting slab with a thinner one maintains the optimal lubrication clearance, effectively reducing wear, vibration, and efficiency losses caused by improper clearance.

[0037] like Figure 3As shown, a countersunk end is provided at the end of the mounting hole 52. The fastener is configured as a hex socket head cap screw that matches the mounting hole 52. The countersunk end is constructed to accommodate the head of the hex socket head cap screw. Thus, the countersunk end helps to prevent interference between the hex socket head cap screw and the upper bearing shell 1.

[0038] The preferred locating pin is a tapered pin. Compared to a cylindrical pin, a tapered pin can eliminate the gap caused by hole machining errors, ensuring that the positioning error of the adjusting block 5 during installation is controlled within ±0.01mm. This ensures the precise alignment of the adjusting block 5 slot 51 with the bearing bush clamp 2 and the upper bearing bush 1, effectively avoiding uneven bearing bush stress caused by positioning deviations and ensuring stable turbine operation.

[0039] To further reduce the assembly difficulty of the adjusting block 5 and the bearing bush clamp 2, the slot 51 and the bearing bush clamp 2 are fitted with a clearance fit. Furthermore, the turbine generates vibrations and dynamic loads during operation, and the clearance fit provides the adjusting block 5 with a certain buffer space. When encountering a sudden impact, the adjusting block 5 can shift slightly within the slot 51, absorbing some of the impact force, reducing the rigid impact on the bearing bush clamp 2 and the upper bearing bush 1, lowering the probability of structural damage, and ensuring the safe and stable operation of the turbine.

[0040] To further enhance the vibration resistance and anti-loosening performance of the adjusting block 5, the slot 51 is preferably a U-shaped slot. Anti-slip textures are provided on the inner wall of the U-shaped slot. The combination of the U-shaped slot and the anti-slip textures forms a dual anti-loosening mechanism. The enveloping structure of the U-shaped slot can buffer vibration impacts, while the anti-slip textures, through their interlocking action, hinder the relative movement between the adjusting block 5 and the bearing.

[0041] When using the stabilizing structure for the front bearing of a steam turbine as proposed in this embodiment, the front bearing is disassembled strictly according to relevant operating procedures after the unit is shut down. Professional measuring tools are used to accurately measure various data according to the steam turbine manufacturer's quality standards. For example, a high-precision outside micrometer is used to measure the bearing clearance, and a level is used to measure the bearing elevation, ensuring the accuracy of the measurement data and providing a reliable basis for subsequent design and adjustments.

[0042] First, measure the position and dimensions of the bearing bush clamp 2 and the bearing cap horizontal plane, and accurately drill and tap holes on the clamp plane through machining. When installing the adjusting block 5, first install the two M14 socket head cap bolts, then ream the holes and fit in two ø12 diameter locating pins, and then tighten the bolts in a crisscross manner to gradually increase the torque, so that the final torque reaches 100 N·m-120 N·m, ensuring that the adjusting block 5 is firmly installed.

[0043] After installation, use feeler gauges and other tools to measure the anti-slip clearance on both sides of the bearing bush. Based on the measurement results, adjust the thickness of the adjusting shims added to the lower part of the anti-slip block to precisely adjust the anti-slip clearance of the bearing bush to 0.20-0.25mm, meeting the technical requirements of the turbine manufacturer.

[0044] Compared to the original anti-jump block, the external dimensions of the adjusting block 5 have been increased from 80*40*17mm to 220*40*17mm, while using the same material. The installation position has also been optimized, with the adjusting block 5 installed on the bearing clamping positions corresponding to the anti-jump blocks on both sides of the upper bearing 1. The adjusting block 5 can better withstand the effects of rotor disturbance forces and oil film pressure changes, preventing the bearing from tilting due to uneven stress. This ensures the stability of the turbine rotor shaft system center, solving problems such as high bearing temperature, large vibration, bearing shedding due to insufficient bearing stability in existing turbine front bearings, and dynamic and static rubbing. This improves the stability of the turbine front bearing, ensuring safe, stable, and long-term operation of the unit, and reducing economic losses caused by equipment failures for power generation companies.

[0045] This utility model is not limited to the specific technical solutions described in the above embodiments. Besides the above embodiments, this utility model may have other implementation methods. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A stabilizing structure for a front bearing of a steam turbine, characterized in that, The bearing bush clamping device installed between the front bearing bush and the upper bearing bush of the steam turbine includes: An adjusting block is installed on the bearing bush clamp of the front bearing of the steam turbine. The adjusting block is provided with a slot, and the bottom of the slot is provided with a positioning hole and a mounting hole. A locating pin is mounted on the bearing bush clamp and is configured to engage with a locating hole to position the adjusting block during installation. And fasteners configured to mate with mounting holes to mount the adjusting block onto the bearing bush clamp; Among them, a pair of adjusting blocks are symmetrically arranged around the axis of the front bearing of the turbine. The adjusting blocks are configured to engage with the bearing bush using a slot, which is used to mechanically limit the upper bearing bush.

2. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, An adjustment gap is provided between the adjustment block and the upper bearing bush, and an adjustment piece is provided within the adjustment gap.

3. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, The slot and the bearing bush clamp are clearance fit.

4. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, The slot is a U-shaped slot, and the inner wall of the U-shaped slot is provided with anti-slip texture.

5. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, The mounting hole has a countersunk end, and the fastener is configured as an internal hex bolt that matches the mounting hole. The countersunk end is configured to be used to insert the head of the internal hex bolt.

6. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, The locating pin is a tapered pin.

7. The stabilizing structure for the front bearing of a steam turbine according to claim 5, characterized in that, The tightening torque of the internal hex bolt is 100 N·m-120 N·m.

8. The stabilizing structure for the front bearing of a steam turbine according to claim 1, characterized in that, The bottom of the card slot is provided with a pair of positioning holes, and the mounting hole is located between the pair of positioning holes.

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