A set of couplings and a steam turbine, a stress calculation method, a calculation terminal machine and a readable storage medium

Abstract

The invention discloses a kind of set coupling and steam turbine, stress calculation method and computing terminal machine and readable storage medium, including integral structure's coupling flange and coupling sleeve, bolt, shaft, key, buckle, stress release groove and small stop ring, coupling flange is provided with bolt, torque is transmitted by bolt, coupling sleeve is interference fit with shaft, key is arranged between coupling sleeve and shaft, the cross section of key is circular and has axial taper, the hardness of coupling sleeve and shaft is same and coupling is drilled keyway after being installed on shaft, then reaming is carried out, so that the taper of keyway and key is matched, torque is transmitted by key, coupling sleeve and shaft are also provided with buckle between, the outer end of key is provided with split ring, buckle is tightly buckled on split ring and not easy to loosen.For avoiding stress concentration, stress release groove is arranged on shaft, to avoid stress mutation, small stop ring is arranged on shaft, the safety reliability and service life of steam turbine generator are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam turbine generator, in particular to a sleeved coupling, a steam turbine, a stress calculation method, a calculation terminal and a readable storage medium. BACKGROUND

[0002] The steam turbine works under the condition of high temperature, high pressure and high speed. The coupling is a connecting device for transmitting power of the steam turbine to the generator. The coupling connects the rotor of the steam turbine and the rotor of the generator, so as to transmit the torque acting on the rotor of the steam turbine to the rotor of the generator, and make the rotor of the generator rotate, thereby generating electric energy. During the operation of the steam turbine generator, the coupling bears the torque and is the carrier of the torque transmission. The coupling is one of the important components of the steam turbine generator. The sleeved coupling is used for the rotor with sleeved impeller structure, because the integral forged coupling hinders the assembly of the rotor with such structure. The sleeved coupling is assembled on the shaft through the key and the appropriate interference fit.

[0003] When designing the steam turbine generator, the available sleeved coupling structure is very limited. As shown in Figure 4 Most of the keys of the existing sleeved coupling use a plurality of tight screws at the outer end. This way is easy to loosen. The inner end direction of the key is quite sensitive to the friction with the end of the coupling sleeve matched with the shaft. When connected, the maximum stress is concentrated in one point, and the crack starts to appear, resulting in fatigue fracture of the shaft. The existing sleeved coupling, when a large axial load is applied to the coupling, the coupling will move to the main part of the rotor, resulting in stress mutation, reducing the safety reliability and service life of the sleeved coupling. Therefore, a new sleeved coupling needs to be designed to solve the above technical problems, and a corresponding calculation method and safety criterion are needed for checking. SUMMARY

[0004] The present application provides a sleeved coupling, a steam turbine, a stress calculation method, a calculation terminal and a readable storage medium to solve the problems in the prior art.

[0005] To achieve the above purpose, the present application adopts the following technical scheme: a sleeved coupling, comprising a coupling flange, a coupling sleeve, a bolt and a key, the coupling flange and the coupling sleeve are of one-piece structure, the coupling flange is provided with a plurality of bolt holes in the circumferential direction, a bolt is arranged in each bolt hole, the torque is transmitted through the bolt, the coupling sleeve is interference-fitted with the shaft, a key groove is arranged between the coupling sleeve and the shaft, the key groove is composed of half grooves arranged on the coupling sleeve and the shaft respectively, the key is arranged in the key groove, and the torque is transmitted through the key.

[0006] Further, the cross section of the key is circular and has axial taper, the axial taper is 6.35mm per 304.8mm length in the diameter direction, the coupling sleeve is sleeved on the shaft, then the key groove is drilled, then the key groove and the taper of the key are matched by reaming, the material hardness of the coupling sleeve and the shaft is same, so that the drill bit does not move when drilling the key groove.

[0007] Further, the buckle ring is arranged between the coupling sleeve and the shaft, the outer end of the key is provided with an open ring, and the buckle ring is buckled on the open ring to prevent loosening.

[0008] Further, to avoid the axial movement of the buckle ring and the open ring in opposite directions, two radial pins with a diameter of 19mm are radially arranged on the key.

[0009] Further, a steam turbine comprises a shaft, a stress relief groove, a small stop ring and a sleeved coupling, the shaft is sleeved with a sleeved coupling, the stress relief groove is arranged on the shaft to avoid stress concentration, the stress relief groove is arranged between the coupling sleeve and the shaft to avoid stress mutation, and the small stop ring is arranged on the shaft to avoid stress mutation, the small stop ring at the end of the coupling sleeve abutting against the shaft shoulder prevents the movement of the coupling to the main part of the rotor under the impact of the axial load, and the small stop ring limits the position of the coupling sleeve.

[0010] Further, the stress relief groove is arranged at a position in line with the end of the coupling sleeve.

[0011] Further, the torsional shear stress of the coupling sleeve is less than half of the torsional shear stress of the shaft, the shear stress of the coupling flange is 1 / 4 of the torsional shear stress of the shaft, and the bending stress of the coupling flange is half of the bending stress of the shaft.

[0012] The application also provides a stress calculation method of a steam turbine, which comprises the following steps:

[0013] Step 1: design the geometric size of a steam turbine, including the diameter D1 of the shaft, the bolt pitch circle diameter D2, the assembly length L, the sleeve diameter D8, the flange chamfer radius R, the flange thickness t1, the thickness t2 of the sleeve above the key groove and the diameter h of the key at the flange nut end, the assembly length L is 2 / 3D1, the flange chamfer radius R is 0.05D8, the flange thickness t1 is D1 / 4, the thickness t2 of the sleeve above the key groove is D1 / 5 or 2h, and the larger value is taken;

[0014] Step 2: calculate the stress of the bolt, the key, the shaft and the stress relief groove,

[0015] The shear stress calculation formula of the bolt which transmits torque by shear force is:

[0016]

[0017] In the formula, τ is the bolt shear stress, KW is the transmitted load, n is the total number of the coupling bolts, N is the shaft speed, and A' is the cross-sectional area of the bolt shear plane.

[0018] The formula for calculating the tensile stress of the frictionally driven bolt is:

[0019]

[0020] In the formula, σ d is the required tensile stress, A is the minimum cross-sectional area of the bolt, and the friction coefficient is 0.25,

[0021] The formula for calculating the shear stress of the key is:

[0022]

[0023] In the formula, τ k is the shear stress of the key, KW is the transmitted load of the coupling, N is the shaft speed, m is the total number of the keys, l3 is the key length, and h avg is the average value of the key diameter,

[0024] The formula for calculating the torsional shear stress of the shaft is:

[0025]

[0026] In the formula, τ s is the shear stress of the shaft at the narrow end of the coupling sleeve, η s is the minimum diameter of the key,

[0027] The formula for calculating the shear stress of the stress relief groove is:

[0028]

[0029] In the formula, τ SR is the shear stress of the stress relief groove, D SR is the diameter of the stress relief groove.

[0030] Step 3: Determine whether the shear stress of the bolt is less than the allowable shear stress of the bolt, which is: maximum working condition yield / 6.563 and short circuit working condition yield / 2.625;

[0031] Step 4: Determine whether the tensile stress of the bolt is less than the allowable tensile stress of the bolt, which is: maximum working condition yield / 5.25 and short circuit working condition yield / 2.1;

[0032] Step 5: judging whether the shear stress of the key is less than the allowable shear stress of the key, the allowable shear stress of the key being: maximum working condition yield / 3.5 and short circuit working condition yield / 1.75;

[0033] Step 6: judging whether the torsional shear stress of the shaft is less than the allowable torsional shear stress of the shaft, the allowable torsional shear stress of the shaft being: maximum working condition 0.177 tensile and short circuit working condition 0.57 yield;

[0034] Step 7: judging whether the shear stress of the stress relief groove is less than the allowable shear stress of the stress relief groove, the allowable shear stress of the stress relief groove being: maximum working condition 0.177 tensile and short circuit working condition 0.57 yield;

[0035] Step 8: if the results of steps 3-7 are all yes, the geometric size design of the steam turbine is qualified, otherwise, re-entering step 1, modifying the geometric size of the steam turbine, repeating steps 2-7 until the geometric size design of the steam turbine is qualified.

[0036] The application further provides a computing terminal machine for realizing the steam turbine stress calculation method, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, and the processor executes the computer program to realize the steam turbine stress calculation method.

[0037] The application further provides a readable storage medium for storing the steam turbine stress calculation method, and the readable storage medium stores a computer program, and the computer program is executed by the processor to realize the steam turbine stress calculation method.

[0038] Compared with the prior art, the application has the beneficial effects that:

[0039] 1、The safety and reliability of the sleeve coupling and the steam turbine are high. The keys and the clamping rings are arranged between the sleeve coupling and the shaft, the cross section of the key is circular and has axial taper, the key groove is drilled after the sleeve coupling is sleeved on the shaft, then the reaming is performed, so that the key groove and the taper of the key are matched, the material hardness of the sleeve coupling and the shaft is the same, so that the drill bit does not move when the key groove is drilled, the open ring is arranged at the outer end of the key, the clamping ring is tightly clamped on the open ring and is not easy to loosen, and the torque of the sleeve coupling is transmitted to the shaft through the key. The safety and reliability of the sleeve coupling and the steam turbine are improved.

[0040] 2, The coupling and steam turbine can avoid stress concentration. The coupling sleeve and the shaft are matched, and the end of the coupling sleeve is sensitive to friction. When connected, the maximum stress is concentrated in one point, cracks appear, and the shaft is broken due to fatigue. In order to avoid stress concentration, a stress release groove is arranged between the coupling sleeve and the shaft, the stress release groove is arranged at a position in line with the end of the coupling sleeve on the shaft, and the stress is released to avoid stress concentration in one point, thereby avoiding fatigue fracture of the shaft. The service life of the steam turbine generator is improved.

[0041] 3, The coupling and steam turbine can avoid stress mutation. The small blocking ring is arranged on the shaft, and when the coupling is impacted by a large axial load, the small blocking ring at the end of the coupling sleeve abutting against the shaft shoulder prevents the movement of the coupling to the main part of the rotor, thereby improving the service life of the steam turbine generator.

[0042] 4, The stress distribution is optimized. The design of the coupling and steam turbine provided by the application can make the stress more evenly distributed on each part of the coupling and steam turbine, thereby improving the safety, reliability and service life of the coupling and steam turbine.

[0043] 5, The stress calculation method is simplified. The application provides a simpler stress calculation method and safety criterion for checking the coupling and steam turbine, so that engineers can more quickly and accurately calculate the stress of the coupling and steam turbine, thereby better designing and optimizing the structure of the coupling and steam turbine. BRIEF DESCRIPTION OF DRAWINGS

[0044] The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification. The illustrations in the drawings serve to explain the preferred embodiments of the present application, and should not be construed as an improper limitation of the present application. In the drawings:

[0045] Figure 1 The structure of the coupling and steam turbine at the end of the steam turbine shaft according to the application is shown in the structure diagram;

[0046] Figure 2 The geometric size of the coupling and steam turbine at the end of the steam turbine shaft according to the application is shown in the structure diagram;

[0047] Figure 3 The calculation program flowchart of the stress calculation method of the coupling and steam turbine according to the application is shown in the structure diagram;

[0048] Figure 4 The structure of the existing coupling and steam turbine at the end of the steam turbine shaft is shown in the structure diagram.

[0049] 1 - coupling flange, 2 - coupling sleeve, 3 - bolt, 4 - shaft, 5 - key, 6 - clasp, 7 - stress relief groove, 8 - small stop ring, 9 - set screw. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0051] Reference is made to Figures 1-3 In order to illustrate the present embodiment, a set coupling includes a coupling flange 1, a coupling sleeve 2, a bolt 3 and a key 5. The coupling flange 1 and the coupling sleeve 2 are of an integrated structure. The coupling flange 1 is provided with a plurality of bolt holes in the circumferential direction. Each bolt hole is provided with a bolt 3. The bolt 3 transmits torque. The coupling sleeve 2 is in interference fit with a shaft 4. A key groove is provided between the coupling sleeve 2 and the shaft 4. The key groove is composed of half grooves provided on the coupling sleeve 2 and the shaft 4 respectively. The key 5 is arranged in the key groove. The key 5 transmits torque.

[0052] The key 5 has a circular cross section and an axial taper. The axial taper is 6.35 mm per 304.8 mm in the diameter direction. The key groove is drilled after the coupling is set on the shaft 4. Then, reaming is performed so that the taper of the key groove and the key 5 are matched. The material hardness of the coupling sleeve 2 and the shaft 4 is the same. Therefore, when the key groove is drilled, the drill bit does not move due to entering the softer material.

[0053] A clasp 6 is provided between the coupling sleeve 2 and the shaft 4. The outer end of the key 5 is provided with an open ring. The clasp 6 is buckled on the open ring to prevent loosening.

[0054] In order to avoid the axial movement of the clasp 6 and the open ring in opposite directions, two radial pins with a diameter of 19 mm are radially passed through the key 5.

[0055] A steam turbine includes a shaft 4, a stress relief groove 7, a small stop ring 8 and a set coupling. The shaft 4 is provided with a set coupling. In order to avoid stress concentration, the shaft 4 is provided with a stress relief groove 7. The stress relief groove 7 is provided between the coupling sleeve 2 and the shaft 4. In order to avoid stress mutation, the shaft 4 is provided with a small stop ring 8. Under the impact of the axial load, the small stop ring 8 at the end of the coupling sleeve 2 which leans against the shaft shoulder prevents the movement of the coupling to the main part of the rotor and limits the coupling sleeve 2.

[0056] The stress relief groove 7 is provided at a position in line with the end of the coupling sleeve 2.

[0057] In the embodiment, the torsional shear stress of the coupling sleeve 2 is less than half of the torsional shear stress of the shaft 4, the shear stress of the coupling flange 1 is about 1 / 4 of the torsional shear stress of the shaft 4, and the bending stress of the coupling flange 1 is about half of the bending stress of the shaft 4.

[0058] The advantages of the coupling sleeve and the steam turbine according to the above embodiment include:

[0059] 1. The safety and reliability of the coupling sleeve and the steam turbine are improved. The key 5 and the clamping ring 6 are arranged between the coupling sleeve 2 and the shaft 4. The cross section of the key 5 is circular, and the key 5 has axial taper. After the coupling sleeve is assembled on the shaft 4, the key groove is drilled, and then the reaming is performed to make the key groove and the taper of the key 5 match. The material hardness of the coupling sleeve 2 and the shaft 4 is the same, so that the drill bit does not move when drilling the key groove. The outer end of the key 5 is provided with an open ring, and the clamping ring 6 is tightly clamped on the open ring and is not easy to loosen. The torque of the coupling sleeve is transmitted to the shaft 4 through the key 5. The safety and reliability of the coupling sleeve and the steam turbine are improved.

[0060] 2. Stress concentration is avoided. The end of the coupling sleeve 2 is quite sensitive to friction when the coupling sleeve 2 and the shaft 4 are matched. When connected, the maximum stress is concentrated at that point, and cracks begin to appear, leading to fatigue fracture of the shaft 4. In order to avoid stress concentration, the stress release groove 7 is arranged between the coupling sleeve 2 and the shaft 4. The stress release groove 7 is arranged at a position in line with the end of the coupling sleeve 2 and the shaft 4, thereby improving the service life of the steam turbine generator.

[0061] 3. Stress mutation is avoided. The small stop ring 8 is arranged on the shaft 4. When the coupling is subjected to a large axial load impact, the small stop ring 8 at the end of the coupling sleeve 2 against the shaft shoulder prevents the coupling from moving to the main part of the rotor, thereby improving the service life of the steam turbine generator.

[0062] 4. Stress distribution is optimized. The design of the coupling sleeve and the steam turbine can make the stress more evenly distributed on each part of the coupling sleeve and the steam turbine, thereby improving the safety and reliability and the service life of the coupling sleeve and the steam turbine.

[0063] As shown in Figures 2-3 the stress calculation method of the coupling sleeve and the steam turbine according to the above embodiment includes the following steps:

[0064] Step 1: design a set of coupling and turbine geometry, including the diameter of the shaft D1 (cm), bolt pitch circle diameter D2 (cm), assembly length L (cm), sleeve diameter D8 (cm), flange chamfer radius R (cm), flange thickness t1 (cm), the thickness of the sleeve above the keyway t2 (cm) and the diameter of the flange nut end key h (cm), the assembly length L is 2 / 3D1, the flange chamfer radius R is 0.05D8, the flange thickness t1 is D1 / 4, the thickness of the sleeve above the keyway t2 is D1 / 5 or 2h, whichever is greater;

[0065] Step 2: calculate the stress of bolt 3, key 5, shaft 4 and stress relief groove 7,

[0066] The shear stress calculation formula of bolt 3 which only transmits torque by shear force is:

[0067]

[0068] In the formula, τ is the shear stress of the bolt (MPa), KW is the transmitted load (kW), n is the total number of coupling bolts, N is the shaft speed (r / min), A' is the cross-sectional area of the bolt shear plane (cm 2 );

[0069] The tensile stress calculation formula of bolt 3 driven by friction is:

[0070]

[0071] In the formula, σ d is the required tensile stress, A is the minimum cross-sectional area of the bolt, in this formula, the friction coefficient is assumed to be 0.25,

[0072] The shear stress calculation formula of the key 5 is:

[0073]

[0074] In the formula, τ k is the shear stress of the key (MPa), KW is the transmitted load of the coupling (kW), N is the rotational speed of the shaft (r / min), m is the total number of keys, l3 is the key length (cm), h avg is the average value of the key diameter (cm),

[0075] The torsional shear stress calculation formula of the shaft 4 is:

[0076]

[0077] In the formula, τ s is the shear stress of the shaft at the narrow end of the coupling sleeve (MPa), η s is the minimum diameter of the key (cm),

[0078] The shear stress calculation formula of the stress relief groove 7 is:

[0079]

[0080] In the formula, τ SR is the shear stress (MPa) of the stress relief groove, D SR is the diameter (cm) of the stress relief groove;

[0081] Step 3: Determine whether the shear stress of the bolt 3 is less than the allowable shear stress of the bolt 3, and the allowable shear stress of the bolt 3 is: maximum working condition yield / 6.563 and short circuit working condition yield / 2.625;

[0082] Step 4: Determine whether the tensile stress of the bolt 3 is less than the allowable tensile stress of the bolt 3, and the allowable tensile stress of the bolt 3 is: maximum working condition yield / 5.25 and short circuit working condition yield / 2.1;

[0083] Step 5: Determine whether the shear stress of the key 5 is less than the allowable shear stress of the key 5, and the allowable shear stress of the key 5 is: maximum working condition yield / 3.5 and short circuit working condition yield / 1.75;

[0084] Step 6: Determine whether the torsional shear stress of the shaft 4 is less than the allowable torsional shear stress of the shaft 4, and the allowable torsional shear stress of the shaft 4 is: maximum working condition 0.177 tensile and short circuit working condition 0.57 yield;

[0085] Step 7: Determine whether the shear stress of the stress relief groove 7 is less than the allowable shear stress of the stress relief groove 7, and the allowable shear stress of the stress relief groove 7 is: maximum working condition 0.177 tensile and short circuit working condition 0.57 yield;

[0086] Step 8: If the results of steps 3-7 are all yes, then the geometric size design of the one set of couplings and steam turbines is qualified, otherwise, re-enter step 1, modify the geometric size of the one set of couplings and steam turbines, and repeat steps 2-7 until the geometric size design of the one set of couplings and steam turbines is qualified.

[0087] The stress calculation method of the one set of couplings and steam turbines can comprehensively evaluate the stress state of the one set of couplings and steam turbines, ensure that it will not fail due to stress problems during use, and improve the safety reliability and service life of the one set of couplings and steam turbines.

[0088] The embodiment is a computing terminal for realizing a coupling and steam turbine stress calculation method, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to realize a coupling and steam turbine stress calculation method.

[0089] The embodiment is a readable storage medium for storing a coupling and steam turbine stress calculation method, and the readable storage medium stores a computer program, and the computer program is executed by a processor to realize a coupling and steam turbine stress calculation method.

[0090] The computer program in the above embodiment can be any common program language, such as C++, Java or Python, etc. The stress calculation of the bolt 3, the key 5, the shaft 4 and the stress release groove 7 of a coupling and steam turbine is programmed, and in the program, a stress calculation method of a coupling and steam turbine is realized, which comprises the following steps:

[0091] 1. Input the geometric dimensions of a coupling and steam turbine, including the inner and outer diameters, lengths and areas and numbers of the bolt 3, the key 5, the shaft 4 and the stress release groove 7, and the rotation diameter, etc.

[0092] 2. Input the load and constraint conditions of a coupling and steam turbine, including the maximum working condition torque, short circuit working condition torque, rotation speed, etc.

[0093] 3. Calculate the stresses of the bolt 3, the key 5, the shaft 4 and the stress release groove 7 in the maximum working condition and the short circuit working condition based on the input parameters, including shear, tensile and torsional shear stresses, etc.

[0094] 4. According to the calculation results and the tensile limit and yield strength of the material, judge whether the stresses of the bolt 3, the key 5, the shaft 4 and the stress release groove 7 in the maximum working condition and the short circuit working condition meet the design requirements, etc.

[0095] 5. According to the calculation results, optimize the design, and adjust the material, geometric dimensions, etc. to meet the design requirements.

[0096] Through actual adjustment and analysis of the assembly and operation conditions, the coupling and steam turbine structure, stress calculation method and computing terminal and readable storage medium proposed in the above embodiment are safe and reliable, simple in structure and process, and convenient for machining, installation, maintenance and other operations, and have high universality and economy. The safety and reliability and service life of the steam turbine generator are improved.

[0097] The above disclosed embodiments of the present application are only used to help explain the present application. The embodiments do not describe all the details of the present application, and the present application is not limited to the specific embodiments described. According to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application.

Claims

1. A stress calculation method of a steam turbine, characterized by: The steam turbine comprises a shaft (4), a stress release groove (7), a small blocking ring (8) and a sleeved coupling, the sleeved coupling is installed on the shaft (4), the stress release groove (7) is arranged on the shaft (4) to avoid stress concentration, and the stress release groove (7) is arranged between the coupling sleeve (2) and the shaft (4); the small blocking ring (8) is arranged on the shaft (4) to avoid stress mutation, the small blocking ring (8) at the end of the coupling sleeve (2) which leans against the shaft shoulder prevents the movement of the coupling towards the main part of the rotor under the impact of the axial load, and the coupling sleeve (2) is limited, the sleeved coupling comprises a coupling flange (1), a coupling sleeve (2), a bolt (3) and a key (5), the coupling flange (1) and the coupling sleeve (2) are of an integrated structure, the coupling flange (1) is provided with a plurality of bolt holes in the circumferential direction, the bolt (3) is arranged in each bolt hole, the torque is transmitted through the bolt (3), the coupling sleeve (2) is in interference fit with the shaft (4), a key groove is arranged between the coupling sleeve (2) and the shaft (4), the key groove is composed of half grooves arranged on the coupling sleeve (2) and the shaft (4) respectively, the key (5) is arranged in the key groove, and the torque is transmitted through the key (5); The stress calculation method comprises the following steps: Step 1: the geometric size of the steam turbine is designed, including the diameter D1 of the shaft, the bolt pitch circle diameter D2, the assembly length L, the sleeve diameter D8, the flange chamfer radius R, the flange thickness t1, the thickness t2 of the sleeve above the key groove and the diameter h of the flange nut end key, the assembly length L is 2 / 3D1, the flange chamfer radius R is 0.05D8, the flange thickness t1 is D1 / 4, the thickness t2 of the sleeve above the key groove is D1 / 5 or 2h, and the larger one is taken; Step 2: the stress of the bolt (3), the key (5), the shaft (4) and the stress release groove (7) is calculated, The shear stress calculation formula of the bolt (3) which transmits the torque through the shear force is: τ= 1.13 x 10 x 1.13 x 10 4 where τ is the bolt shear stress, KW is the transmitted load, n is the total number of coupling bolts, N is the shaft speed, A A is the cross-sectional area of the bolt shear plane. The tensile stress calculation formula of the bolt (3) which is driven by friction is: σ d = ×1.13×10 4 In the formula, σ d Given the required tensile stress, A is the minimum cross-sectional area of ​​the bolt, and the coefficient of friction is 0.

25. The shear stress calculation formula of the key (5) is: τ k = ×1.13×10 4 In the formula, τ k Where is the shear stress of the key, KW is the load transmitted by the coupling, N is the rotational speed of the shaft, m is the total number of keys, l3 is the key length, and h is the shear stress of the key. avg The average value of the bond diameter. The torsional shear stress calculation formula of the shaft (4) is: τ s = ×1.13×10 4 where τ s is the shear stress at the narrow end of the shaft of the coupling sleeve, s is the minimum diameter of the key, The shear stress calculation formula of the stress release groove (7) is: τ SR = ×1.13×10 4 where τ SR is the shear stress of the stress relief groove, D SR is the diameter of the stress relief groove; Step 3: whether the shear stress of the bolt (3) is less than the allowable shear stress of the bolt (3) is judged, the allowable shear stress of the bolt (3) is: maximum working condition yield / 6.563 and short circuit working condition yield / 2.625; Step 4: whether the tensile stress of the bolt (3) is less than the allowable tensile stress of the bolt (3) is judged, the allowable tensile stress of the bolt (3) is: maximum working condition yield / 5.25 and short circuit working condition yield / 2.1; Step 5: whether the shear stress of the key (5) is less than the allowable shear stress of the key (5) is judged, the allowable shear stress of the key (5) is: maximum working condition yield / 3.5 and short circuit working condition yield / 1.75; Step 6: whether the torsional shear stress of the shaft (4) is less than the allowable torsional shear stress of the shaft (4) is judged, the allowable torsional shear stress of the shaft (4) is: maximum working condition 0.177 tensile and short circuit working condition 0.57 yield. Step 7: judging whether the shear stress of the stress relief groove (7) is less than the allowable shear stress of the stress relief groove (7), the allowable shear stress of the stress relief groove (7) being 0.177 tensile in the maximum working condition and 0.57 yield in the short circuit working condition; Step 8: if the judgment results in steps 3-7 are all yes, the geometric size design of the steam turbine is qualified, otherwise, re-entering step 1, modifying the geometric size of the steam turbine, repeating steps 2-7 until the geometric size design of the steam turbine is qualified.

2. A stress calculation method of a steam turbine according to claim 1, characterized by: The cross section of the key (5) is circular and has axial taper, the axial taper being 6.35 mm per 304.8 mm length in the diameter direction, the coupling sleeve is drilled after being fitted on the shaft (4), then reaming is performed, so that the taper of the key groove and the key (5) are matched, the material hardness of the coupling sleeve (2) and the shaft (4) is the same, so that the drill bit does not move when drilling the key groove due to entering the softer material.

3. A stress calculation method of a steam turbine according to claim 1, characterized by: The clasp (6) is arranged between the coupling sleeve (2) and the shaft (4), the outer end of the key (5) is provided with an open ring, and the clasp (6) is buckled on the open ring to prevent loosening.

4. A stress calculation method of a steam turbine according to claim 3, characterized by: In order to avoid the axial movement of the clasp (6) and the open ring in opposite directions, two radial pins with a diameter of 19 mm are radially arranged on the key (5).

5. A stress calculation method of a steam turbine according to claim 1, characterized by: The stress relief groove (7) is arranged at a position in line with the end of the shaft (4) and the coupling sleeve (2).

6. A stress calculation method of a steam turbine according to claim 1, characterized by: The torsional shear stress of the coupling sleeve (2) is less than half of the torsional shear stress of the shaft (4), the shear stress of the coupling flange (1) is 1 / 4 of the torsional shear stress of the shaft (4), and the bending stress of the coupling flange (1) is half of the bending stress of the shaft (4).

7. A computing terminal for implementing a method of stress calculation for a steam turbine, characterized in that: It comprises a memory, a processor and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to realize the stress calculation method of the steam turbine of claim 1.

8. A readable storage medium storing a method for calculating stress of a steam turbine, characterized by: The computer program is stored on the readable storage medium, and the computer program is executed by the processor to realize the stress calculation method of the steam turbine of claim 1.

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