Structure for connecting elastic floating joint with turbine blade

Abstract

The utility model discloses a turbine blade structure connected by an elastic floating joint, which comprises a wheel disc main body and a blade main body, a dovetail groove is arranged on the side surface of the wheel disc main body, a dovetail pin is arranged at the bottom of the blade main body, an elastic fixing piece is arranged in the dovetail groove, and a fixing groove opposite to the elastic fixing piece is arranged on the side surface of the dovetail pin. A certain thermal expansion gap exists between the dovetail groove and the dovetail pin, the elastic fixing piece comprises a first reed, a second reed and a third reed, the fixing groove comprises a first groove, a second groove and a third groove, the first reed is fixedly installed at the bottom of the dovetail groove, the second reed is fixedly installed on the side face of the dovetail groove, and the third reed is fixedly installed on the bottom of the dovetail groove. The third reed is fixedly installed on the side, away from the second reed, of the dovetail groove, and the elastic fixing piece is inserted into the fixing groove and clamped with the fixing groove. The elastic fixing piece is matched with the fixing groove, so that the problems of stress concentration, mechanical interference, abrasion and the like caused by interference fit are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbines, in particular to a structure of connecting steam turbine blades with an elastic floating joint. Background Art

[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam power device. High-temperature and high-pressure steam passes through a fixed nozzle to become an accelerated airflow and is then sprayed onto the blades, causing the rotor with the blade rows to rotate and perform work externally. Steam turbines are the main equipment in modern thermal power plants and are also used in the metallurgical industry, chemical industry, and ship power plants.

[0003] In the prior art, steam turbine blades and disks are mostly connected by mortise and tenon structures. Steam turbine blades will expand due to heat in a high temperature environment, causing the blades to squeeze the disk, resulting in stress concentration at the connection between the disk and the blades, the root of the blades or the disk itself, increasing the risk of material fatigue, creep and cracking. Due to thermal stress concentration and mechanical interference, the vibration level of the equipment during operation will increase significantly, which will not only accelerate component fatigue, but may also cause resonance, resulting in a sharp increase in vibration. The cumulative effect of high stress, mechanical interference, vibration and wear will greatly shorten the service life of the disk, blades and related components (such as bearings, seals, etc.). Frequent maintenance and replacement not only increase operation and maintenance costs, but may also lead to unplanned downtime, affecting the availability of equipment and the overall economic benefits of the power plant. Therefore, a flexible floating joint is needed to connect the steam turbine blade structure to solve the above problems. Utility Model Content

[0004] The utility model aims to provide an elastic floating joint for connecting a steam turbine blade structure, which has the advantages of good thermal stability and low wear, and solves the problem in the prior art of fatigue wear of the blades caused by thermal expansion and mutual compression between the wheel disc and the blades of the steam turbine in a high temperature environment.

[0005] To achieve the above object, the utility model provides the following technical solution: an elastic floating joint connects a turbine blade structure, including a wheel disc body and a blade body, a dovetail groove is arranged on the side of the wheel disc body, a dovetail pin is arranged on the bottom of the blade body, an elastic fixing piece is arranged in the dovetail groove, and a fixing groove opposite to the elastic fixing piece is arranged on the side of the dovetail pin;

[0006] There is a certain thermal expansion gap between the dovetail slot and the dovetail pin, the elastic fixing member includes a first reed, a second reed and a third reed, the fixing slot includes a first groove, a second groove and a third groove, the first reed is fixedly installed at the bottom of the dovetail slot, the second reed is fixedly installed on the side of the dovetail slot, the third reed is fixedly installed on the side of the dovetail slot away from the second reed, and the elastic fixing member is inserted into the fixing slot and clamped therewith.

[0007] As a preferred embodiment of the utility model of the elastic floating joint connecting the turbine blade structure, the elastic fixing piece is made of tungsten-molybdenum alloy sheet.

[0008] As a preferred elastic floating joint connecting turbine blade structure of the utility model, a limiting protrusion and a supporting protrusion are provided on the top of the elastic fixing part, the height of the supporting protrusion is higher than the height of the limiting protrusion, the limiting protrusion is an "n"-shaped structure, and the supporting protrusion is a bow-shaped structure.

[0009] As a preferred embodiment of the utility model of the elastic floating joint connecting the turbine blade structure, a limit block is fixedly installed on the side of the dovetail groove.

[0010] As a preferred elastic floating joint connecting turbine blade structure of the utility model, the upper end face of the limit block is provided with a countersunk hole, a fixing bolt is provided in the countersunk hole, and a screw hole is provided at the bottom of the dovetail groove. The fixing bolt passes through the countersunk hole and is inserted into the screw hole to be threadedly connected to the wheel disc.

[0011] As a preferred embodiment of the utility model of the elastic floating joint connecting the turbine blade structure, the blade body is a hollow structure.

[0012] As a preferred embodiment of the utility model of the elastic floating joint connecting the turbine blade structure, the blade body is provided with air holes.

[0013] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0014] 1. The utility model reserves a thermal expansion gap between the dovetail groove and the dovetail pin, and adopts a matching method between the elastic fixing part and the fixing groove to ensure that the blades and the impeller can adapt to their respective thermal expansion when running at high temperature, avoid stress concentration, mechanical interference and wear caused by interference fit, and extend the service life of the equipment.

[0015] 2. The utility model realizes effective limitation of the axial position of the blade by the limiting protrusion and the supporting protrusion on the elastic fixing part, thereby preventing the blade from excessively moving in the axial direction. At the same time, the supporting protrusion ensures that the blade fits the disk, avoiding the blade from shaking due to the empty space, thereby enhancing the stability of the blade operation. The elastic fixing part is made of tungsten-molybdenum alloy sheet, and utilizes the excellent high-temperature resistance and high-temperature elasticity of tungsten-molybdenum alloy to ensure that a good elastic connection effect can be maintained in the high-temperature environment of the turbine, maintain stable contact between the blade and the disk, and avoid blade vibration, increased noise and decreased efficiency due to elastic failure. The elastic fixing part has a certain energy absorption and buffering effect, which can effectively reduce the impact of instantaneous airflow pulses in the steam turbine on the blade body and reduce the probability of its breakage.

[0016] 3. The blade body of the utility model adopts a hollow structure design, which reduces the mass and helps to improve the rotational inertia ratio of the rotor, thereby improving the starting performance and dynamic response of the turbine. At the same time, the hollow structure allows the inner end surface of the blade to dissipate heat. The pore design on the blade body enhances the overall heat dissipation efficiency and effectively reduces the performance degradation of the blade caused by thermal deformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 For the utility model Figure 1 Enlarged view of point A in the middle;

[0019] Figure 3 It is a structural schematic diagram of the blade body and the elastic fixing member in the first perspective of the present utility model in the matching state;

[0020] Figure 4 It is a structural schematic diagram of the blade body and the elastic fixing member in the second viewing angle of the utility model in the matching state;

[0021] Figure 5 This is a schematic diagram of the dovetail pin structure of the utility model;

[0022] Figure 6 It is a schematic diagram of the structure of the elastic fixing member of the utility model.

[0023] In the figure: 1. wheel body; 101. dovetail groove; 102. screw hole; 110. limit block; 111. countersunk hole; 112. fixing bolt; 2. blade body; 202. air hole; 210. dovetail pin; 220. fixing groove; 221. first groove; 222. second groove; 223. third groove; 3. elastic fixing member; 301. first spring leaf; 302. second spring leaf; 303. third spring leaf; 310. limit protrusion; 320. supporting protrusion. DETAILED DESCRIPTION

[0024] See also Figure 1-Figure 6 The elastic floating joint connects the turbine blade structure, including a wheel disc body 1 and a blade body 2. A dovetail groove 101 is arranged on the side of the wheel disc body 1, a dovetail pin 210 is arranged on the bottom of the blade body 2, an elastic fixing member 3 is arranged in the dovetail groove 101, and a fixing groove 220 opposite to the elastic fixing member 3 is arranged on the side of the dovetail pin 210;

[0025] There is a certain thermal expansion gap between the dovetail slot 101 and the dovetail pin 210. The elastic fixing member 3 includes a first reed 301, a second reed 302 and a third reed 303. The fixing slot 220 includes a first groove 221, a second groove 222 and a third groove 223. The first reed 301 is fixedly installed at the bottom of the dovetail slot 101, the second reed 302 is fixedly installed on the side of the dovetail slot 101, and the third reed 303 is fixedly installed on the side of the dovetail slot 101 away from the second reed 302. The elastic fixing member 3 is inserted into the fixing slot 220 and clamped therewith.

[0026] Furthermore, the elastic fixing member 3 is made of tungsten-molybdenum alloy sheet.

[0027] Tungsten-molybdenum alloy has excellent high temperature resistance, which enables it to maintain a high elastic modulus and a certain tensile strength in the high temperature environment of the steam turbine, and has high temperature elastic properties that are superior to many metal materials.

[0028] Furthermore, a limiting protrusion 310 and a supporting protrusion 320 are provided on the top of the elastic fixing member 3. The height of the supporting protrusion 320 is higher than that of the limiting protrusion 310. The limiting protrusion 310 is an "n"-shaped structure, and the supporting protrusion 320 is an arched structure.

[0029] The edge of the fixing groove 220 is clamped by the limiting protrusion 310 to limit the axial displacement of the blade body 2, and the blade body 2 is supported by the supporting protrusion 320 so that the upper end surface of the dovetail pin 210 is fixedly fitted with the top of the dovetail groove 101, thereby avoiding shaking caused by too much space between the blade body 2 and the wheel disc.

[0030] Furthermore, a limit block 110 is fixedly installed on the side of the dovetail groove 101 .

[0031] The dovetail groove 101 is blocked by the limiting block 110 to prevent the blade from encountering axial airflow pulses, which would cause the elastic fixing member 3 to separate from the fixing groove 220 , thereby improving the stability of the blade body 2 .

[0032] Furthermore, a countersunk hole 111 is provided on the upper end surface of the limit block 110, a fixing bolt 112 is provided in the countersunk hole 111, a screw hole 102 is provided at the bottom of the dovetail groove 101, and the fixing bolt 112 passes through the countersunk hole 111 and is inserted into the screw hole 102 to be threadedly connected with the wheel.

[0033] The limit block 110 is fixed to the wheel disc by bolts to improve the stability of the limit block 110, and the countersunk hole 111 design will not increase the wind resistance of the wheel disc.

[0034] Furthermore, the blade body 2 is a hollow structure.

[0035] The hollow structure design reduces the mass of the blade body 2 and enables the inner end surface of the blade body 2 to dissipate heat, thereby improving the heat dissipation efficiency of the blade body 2 and reducing its thermal deformation.

[0036] Furthermore, the blade body 2 is provided with air holes 202 .

[0037] When installing the blade, the dovetail pin 210 of the blade body 2 is aligned with the dovetail groove 101 of the disc body 1 and inserted therein, so that the elastic fixing member 3 is stuck in the corresponding fixing groove 220, and the initial fixation of the disc body 1 and the blade body 2 is completed. Then the limit block 110 is fixedly installed at the end of the dovetail groove 101 by the fixing bolt 112, and the fixation of the disc body 1 and the blade body 2 is completed. When the disc rotates at high speed in the steam turbine, the blade body 2 fits with the top of the dovetail groove 101 under the action of centrifugal force. As the temperature gradually increases, the dovetail pin 210 and the dovetail groove 101 squeeze the supporting protrusion 320, causing it to undergo elastic deformation, thereby avoiding the disc body 1 and the blade body 2 from squeezing each other, causing excessive stress on the blade body 2, and reducing the risk of fatigue, creep and cracking of the blade body 2.

[0038] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An elastic floating joint connecting a steam turbine blade structure, comprising a disk body (1) and a blade body (2), wherein a dovetail groove (101) is arranged on the side of the disk body (1), and a dovetail pin (210) is arranged on the bottom of the blade body (2), characterized in that: An elastic fixing member (3) is arranged in the dovetail groove (101), and a fixing groove (220) opposite to the elastic fixing member (3) is arranged on the side surface of the dovetail pin (210); There is a certain thermal expansion gap between the dovetail groove (101) and the dovetail pin (210); the elastic fixing member (3) comprises a first reed (301), a second reed (302) and a third reed (303); the fixing groove (220) comprises a first groove (221), a second groove (222) and a third groove (223); the first reed (301) is fixedly mounted on the bottom of the dovetail groove (101); the second reed (302) is fixedly mounted on the side of the dovetail groove (101); the third reed (303) is fixedly mounted on the side of the dovetail groove (101) away from the second reed (302); and the elastic fixing member (3) is inserted into the fixing groove (220) and clamped therewith.

2. The elastic floating joint connecting steam turbine blade structure according to claim 1 is characterized in that: The elastic fixing piece (3) is made of a tungsten-molybdenum alloy sheet.

3. The elastic floating joint connecting steam turbine blade structure according to claim 2 is characterized in that: A limiting protrusion (310) and a supporting protrusion (320) are arranged on the top of the elastic fixing member (3); the height of the supporting protrusion (320) is higher than the height of the limiting protrusion (310); the limiting protrusion (310) is an "n"-shaped structure, and the supporting protrusion (320) is an arched structure.

4. The elastic floating joint connecting steam turbine blade structure according to claim 1 is characterized in that: A limiting block (110) is fixedly mounted on the side of the dovetail groove (101).

5. The elastic floating joint connecting steam turbine blade structure according to claim 4 is characterized in that: The upper end surface of the limit block (110) is provided with a countersunk hole (111), a fixing bolt (112) is provided in the countersunk hole (111), and the bottom of the dovetail groove (101) is provided with a screw hole (102), and the fixing bolt (112) passes through the countersunk hole (111) and is inserted into the screw hole (102) to be threadedly connected with the wheel disc.

6. The elastic floating joint connecting steam turbine blade structure according to claim 1 is characterized in that: The blade body (2) is a hollow structure.

7. The elastic floating joint connecting steam turbine blade structure according to claim 6 is characterized in that: The blade body (2) is provided with an air hole (202).

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