Axial positioning structure for whole-circle self-locking blade

Abstract

The invention discloses an axial positioning structure for a whole circle of self-locking blades. The axial positioning structure comprises the blades and a wheel disc. Pin holes for positioning are formed in the contact surfaces of the steam inlet sides of the intermediates of the two adjacent blades, and combined positioning pins are arranged in the pin holes; the combined positioning pin comprises a first half pin, a second half pin and an L-shaped pin, wherein pin crowns are arranged at the lower ends of the first half pin and the second half pin. The pin hole comprises a back arc key groove matched with the first half pin, an inner arc key groove matched with the second half pin and a rectangular groove matched with the L-shaped pin, and the back arc key groove and the inner arc key groove are the same in structure and are oppositely arranged; the other end of the rectangular groove penetrates through the lower edge of the middle body; a rim pin hole matched with the L-shaped pin is formed in the rim of the wheel disc; a groove matched with the vertical section of the L-shaped pin is reserved in the side, away from the first half pin, of the second half pin. The L-shaped pin is matched with the rectangular groove and can move up and down in the rectangular groove. The bearing distribution of the tenon teeth and the tenon grooves is improved, and the problems that the bottom space of the tenon grooves is insufficient, and arrangement is limited are solved.

Description

Technical Field

[0001] The invention relates to the axial positioning of turbine blades, and in particular to an axial positioning structure for a full circle of self-locking blades. Background Art

[0002] Full circle self-locking blades are widely used in the design of long turbine blades; the characteristic is that the design of long turbine blades adopts the friction damping structure of integral shroud and boss tie rod (or only one of the above two). Tenon blade root has strong load-bearing capacity and is widely used in the blade root structure of low-pressure long blades of high-speed and high-power turbine units; because it is axially assembled, an axial positioning structure is required to prevent the tenon blade root from sliding out of the tenon groove due to the impact of airflow force.

[0003] However, in order to reduce the risk of fatigue failure of turbine blades due to vibration, self-locking connection structures of the blade body, such as integral V-shaped shrouds and boss tie rods, are applied to the structural design of the turbine blades. The application of this blade body connection structure will change the assembly method of the tenon-tooth turbine blades from single pieces being installed into the tenon groove one by one to a whole circle of blades being installed into the tenon groove simultaneously, which brings difficulties to the arrangement of the axial positioning structure of the turbine blades.

[0004] The layout of the axial positioning structure of the tenon root turbine blade needs to comprehensively consider the layout space, the tenon and the tenon groove stress distribution. For the tenon root turbine blade with self-locking blade body, especially the high-speed turbine blade, the tenon groove size is small, there is not enough space to arrange the axial positioning device at the bottom of the tenon groove, and the bottom of the tenon groove is a high stress area. Summary of the invention

[0005] The purpose of the present invention is to provide an axial positioning structure for a full circle of self-locking blades in response to the deficiencies of the prior art; the axial positioning structure is adopted to avoid weakening the strength of the bottom of the tenon, improve the load distribution of the tenon teeth and the tenon, and solve the problems of insufficient space and limited layout at the bottom of the tenon.

[0006] The technical purpose of the present invention is achieved by the following technical solutions: An axial positioning structure for a full circle of self-locking blades, comprising a blade and a wheel; a contact surface on the steam inlet side of the intermediate body of two adjacent blades is provided with a pin hole for positioning, and a combined positioning pin is arranged in the pin hole; the combined positioning pin comprises a first half pin and a second half pin and an L-shaped pin with a pin crown at the lower end; the pin hole comprises a back arc keyway matched with the first half pin, an inner arc keyway matched with the second half pin, and a rectangular groove matched with the L-shaped pin, and the back arc keyway and the inner arc keyway have the same structure and are arranged oppositely; one end of the rectangular groove is connected to the inner arc keyway , and the other end thereof passes through the lower edge of the intermediate body; the rim of the wheel disc is provided with a rim pin hole which cooperates with the L-shaped pin; the circular pin composed of the first half pin and the second half pin is adapted to the pin hole and can rotate in the pin hole; a groove which cooperates with the vertical section of the L-shaped pin is reserved on the side of the second half pin away from the first half pin; the L-shaped pin is adapted to the rectangular groove and can move up and down in the rectangular groove; after the L-shaped pin is placed in the rectangular groove, the vertical section of the L-shaped pin enters the inner arc key groove, and its lower end is flush with the lower end of the rectangular groove, and the lower end of the L-shaped pin is supported by an auxiliary gasket.

[0007] Preferably, the main bodies of the first half pin and the second half pin are semi-cylindrical structures; the first pin crown is a semi-conical structure; the second pin crown is a long strip structure, the front-to-back length of which is equal to the diameter of the first pin crown, and the left-right width of which is smaller than the radius of the first pin crown; The sum of the thickness of the vertical section of the L-shaped pin and the left and right widths of the second pin crown is less than or equal to the radius of the first pin crown.

[0008] Preferably, the outer diameter of the main body of the first half pin and the second half pin is ψ; the height of the first pin crown and the second pin crown of the first half pin and the second half pin is A; the diameter of the first pin crown and the front-to-back length of the second pin crown are ф; The heights of the horizontal and vertical sections of the L-shaped pin are C and B respectively, its axial width is D, and its thickness is E. The ψ≈0.5ф, B=A, A+1.0MM≤C=≤A+4.0mm, D=0.5ф~1.0ф, and E=0.5ф.

[0009] Preferably, the axial center of the rectangular groove is consistent with the axial center of the back arc key groove; the axial position of the wheel rim pin hole is consistent with the axial position of the rectangular groove.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention avoids weakening the strength of the bottom of the tenon groove, improves the load distribution of the tenon teeth and the tenon groove, and solves the problems of insufficient space and limited layout at the bottom of the tenon groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the assembly of a full circle of self-locking blades; Figure 2 It is a schematic diagram of the structure of the present invention; Figure 3 yes Figure 2 A schematic diagram of the structure of the first half pin and the second half pin of the combined positioning pin; Figure 4 yes Figure 2 Schematic diagram of the structure of the L-shaped pin; Figure 5 It is a schematic diagram of the combined positioning pin before the whole circle of self-locking blades are installed into the mortise and tenon groove; Figure 6 It is a schematic diagram of the combined positioning pin after the entire circle of self-locking blades are installed in the mortise and tenon groove; Figure 7 This is a schematic diagram of the punching and riveting after the entire circle of self-locking blades are installed into the mortise and tenon.

[0012] Reference numerals: 1—blade; 11—blade root; 12—intermediate body; 2—wheel disc; 21—mortise and tenon groove; 22—wheel rim; 3—pin hole; 4—combined positioning pin; 41—first half pin; 411—first pin crown; 42—second half pin; 421—second pin crown; 43—L-shaped pin; 431—horizontal section; 432—vertical section; 5—Auxiliary gasket. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0016] like Figure 1 — Figure 5As shown, an axial positioning structure for a full circle of self-locking blades includes a blade 1 and a wheel disc 2; a contact surface on the steam inlet side of the intermediate body 12 of two adjacent blades 1 is provided with a positioning pin hole 3, and a combined positioning pin 4 is arranged in the pin hole 3; the combined positioning pin 4 includes a first half pin 41, a second half pin 42 and an L-shaped pin 43 with a pin crown at the lower end; the pin hole 3 includes a back arc keyway matched with the first half pin 41, an inner arc keyway matched with the second half pin 42 and a rectangular groove matched with the L-shaped pin 43, and the back arc keyway and the inner arc keyway have the same structure and are arranged oppositely; one end of the rectangular groove is connected with the inner arc keyway, and the other end thereof passes through the lower edge of the intermediate body 12; the wheel rim 22 of the wheel disc 2 is provided with a wheel rim pin hole matched with the L-shaped pin 43; the circular pin composed of the first half pin 41 and the second half pin 42 is adapted to the pin hole 3 and can rotate in the pin hole 3; the second half pin 42 has a groove matched with the vertical section 432 of the L-shaped pin 43 on the side away from the first half pin 41; The L-shaped pin 43 is adapted to the rectangular groove and can move up and down in the rectangular groove; after the L-shaped pin 43 is placed in the rectangular groove, the vertical section 432 of the L-shaped pin 43 enters the inner arc key groove, and its lower end is flush with the lower end of the rectangular groove, and the lower end of the L-shaped pin 43 is supported by the auxiliary gasket 5. The adoption of this technical measure solves the problem of insufficient space at the bottom of the tenon groove 21 and limited layout, avoids weakening the bottom strength of the tenon groove 21, and improves the load distribution of the tenon teeth and the tenon groove 21.

[0017] like Figure 1 As shown, in this embodiment, the tenon root turbine blade with a self-locking connection structure for the blade body such as an integral V-shaped belt has a radial angle of η and an assembly inclination angle of θ. Due to the V-shaped belt being locked in place, the entire circle of self-locking blades needs to be synchronously installed into the tenon groove 21.

[0018] like Figure 1 As shown, the blade root 11 of the blade 1 is assembled in the tenon groove 21 of the wheel disc 2. The blade root 11 is a tenon tooth blade root. The contact surface on the steam inlet side of the intermediate body 12 of two adjacent blades 1 is provided with a pin hole 3 for positioning. Specifically, the contact surface on the steam inlet side of the intermediate body 12 of two adjacent blades 1 is a back arc contact surface and an inner arc contact surface; accordingly, the pin hole 3 includes a back arc key groove that cooperates with the first half pin 41, an inner arc key groove that cooperates with the second half pin 42, and a rectangular groove that cooperates with the L-shaped pin 43. One end of the rectangular groove is connected to the inner arc key groove, and the other end thereof passes through the lower edge of the intermediate body 12. In actual use, the rim 22 of the wheel disc 2 is provided with a rim pin hole that cooperates with the L-shaped pin 43. Specifically, the rim pin hole corresponds to the transverse section 431 of the L-shaped pin 43.

[0019] like Figure 3 — Figure 6As shown, the first half pin 41 and the second half pin 42 placed in the back arc keyway and the inner arc keyway are arranged oppositely. The main body of the first half pin 41 and the second half pin 42 is a semi-cylindrical structure. After the first half pin 41 and the second half pin 42 are installed in the pin hole 3, the upper end surface of the main body of the first half pin 41 and the second half pin 42 is lower than the upper end surface of the pin hole 3. The first pin crown 411 is a semi-conical structure; the second pin crown 421 is a long strip structure, the front and rear length of which is equal to the diameter of the first pin crown 411, and the left and right width is less than the radius of the first pin crown 411; the sum of the thickness of the vertical section 432 of the L-shaped pin 43 and the left and right width of the second pin crown 421 is less than or equal to the radius of the first pin crown 411. In actual use, the back arc keyway corresponds to the main body of the first half pin 41 and the first pin crown 411 to form the upper section of the back arc keyway of the semi-cylindrical structure and the lower section of the back arc keyway of the semi-conical structure; the back arc keyway and the inner arc keyway have the same structure and are arranged oppositely. Since the vertical section 432 of the L-shaped pin 43 needs to be inserted into the inner arc keyway, a groove matching the vertical section 432 of the L-shaped pin 43 is left on the side of the second half pin 42 away from the first half pin 41; the second pin crown 421 can be a semi-conical structure with a groove matching the vertical section 432 of the L-shaped pin 43 when in use. However, there is a problem of difficulty in alignment between the groove and the vertical section 432 when matching, which makes it difficult for the vertical section 432 of the L-shaped pin 43 to be inserted into the groove; therefore, the protrusions on both sides of the original groove on the second pin crown 421 are removed to make it a long strip structure. This technical measure is adopted to facilitate the vertical section 432 of the L-shaped pin 43 to be quickly inserted into the inner arc keyway, thereby improving assembly efficiency.

[0020] The first half pin 41, the second half pin 42, and the L-shaped pin 43 are respectively matched with the clearances between the back arc keyway, the inner arc keyway, and the rectangular groove. In actual use, the circular pin composed of the first half pin 41 and the second half pin 42 is adapted to the pin hole 3 composed of the back arc keyway and the inner arc keyway, and can rotate in the pin hole 3; the L-shaped pin 43 can slide up and down in the rectangular groove. The concave edges of the first half pin 41, the second half pin 42, and the L-shaped pin 43 are rounded and the convex edges are slightly chamfered, wherein the chamfer size is 0~0.1mm larger than the rounded size, and the matching clearances of the remaining parts are all 0~0.05mm. Among them, the L-shaped pin 43 adopts a convex edge with a slight chamfer to avoid interference with the fillets of the back arc keyway and the inner arc keyway.

[0021] In this embodiment, the outer diameter of the first half pin 41 and the second half pin 42 is ψ; the height of the first pin crown 411 and the second pin crown 421 of the first half pin 41 and the second half pin 42 is A; the outer diameter of the first pin crown 411 and the second pin crown 421 is ф; the heights of the horizontal section 431 and the vertical section 432 of the L-shaped pin 43 are C and B respectively, the axial width is D, and the thickness is E, ψ≈0.5ф, B=A, A+1.0MM≤C=≤A+4.0mm, D=0.5ф~1.0ф, E=0.5ф. Among them, the width of the second pin crown 421 is 0.25ф, the thickness of the vertical section 432 is 1 / 2E, because E=0.5ф; the thickness of the vertical section 432 is 0.25ф.

[0022] The pin hole 3 corresponds to the height J of the upper section of the pin hole 3 of the main body of the first half pin 41 and the second half pin 42 ≥ 1.3A.

[0023] The depth of the wheel rim pin hole is F, the clearance between the wheel rim 22 and the lower edge of the intermediate body 12 of the blade root 11 is G, and the upper height of the L-shaped pin 43 is B; the relationship B=F+G is satisfied, and the step surface of the L-shaped pin 43 is higher than the H value of the lower edge of the intermediate body 12 of the adjacent blade 1, H≥1mm; In actual use, the radial inclination angle α of the L-shaped pin 43 is 90°+0.5η, and the axial inclination angle β is 90°+θ.

[0024] The axial center of the rectangular groove is consistent with the axial center of the back arc key groove; the axial position of the wheel rim pin hole is consistent with the axial position of the rectangular groove.

[0025] During assembly, the first half pin 41, the second half pin 42 and the L-shaped pin 43 need to be placed in the back arc keyway, the inner arc keyway and the rectangular groove respectively, and the positions of the first half pin 41, the second half pin 42 and the L-shaped pin 43 need to be adjusted to achieve the axial positioning of the entire circle of self-locking blades.

[0026] The specific assembly method is as follows: Before the whole circle of self-locking blades are installed into the mortise and tenon groove 21, the first half pin 41 and the second half pin 42 are respectively placed into the back arc key groove and the inner arc key groove; the L-shaped pin 43 is placed into the rectangular groove, so that the vertical section 432 of the L-shaped pin 43 faces upward, and the horizontal section 431 of the L-shaped pin 43 faces downward, and the vertical section 432 of the L-shaped pin 43 enters the inner arc key groove, and its lower end is flush with the lower end of the rectangular groove, and the lower end of the horizontal section 431 of the L-shaped pin 43 is supported by the auxiliary gasket 5. In actual use, by setting the auxiliary gasket 5 to support the L-shaped pin 43, the L-shaped pin 43 remains in the rectangular groove, so that the whole circle of self-locking blades can be installed into the mortise and tenon groove 21.

[0027] When a whole circle of self-locking blades is installed into the mortise and tenon groove 21, when the whole circle of self-locking blades is installed until the blade root 11 is flush with the end surface of the wheel disc 2, the auxiliary gaskets 5 are taken out one by one, and the rotor is rotated to make the L-shaped pin 43 sink along the rectangular groove to the corresponding wheel rim pin hole, and the first half pin 41 and the second half pin 42 are rotated 90°; the radial space left by the sinking of the L-shaped pin 43 is blocked, and the pin hole 3 on the upper surface of the intermediate body 12 of the blade 1 is punched and riveted to limit the rotation of the first half pin 41 and the second half pin 42.

[0028] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An axial positioning structure for a full circle of self-locking blades, comprising blades and a wheel; a pin hole for positioning is provided on the contact surface on the steam inlet side of the intermediate body of two adjacent blades, characterized in that: A combined positioning pin is provided in the pin hole; the combined positioning pin comprises a first half pin and a second half pin with a pin crown at the lower end and an L-shaped pin; The pin hole includes a back arc keyway matched with the first half pin, an inner arc keyway matched with the second half pin, and a rectangular slot matched with the L-shaped pin. The back arc keyway and the inner arc keyway have the same structure and are arranged oppositely; One end of the rectangular groove is connected to the inner arc key groove, and the other end thereof passes through the lower edge of the intermediate body; the wheel rim of the wheel disc is provided with a wheel rim pin hole matched with the L-shaped pin; The circular pin composed of the first half pin and the second half pin is adapted to the pin hole and can rotate in the pin hole; A groove matching the vertical section of the L-shaped pin is left on the side of the second half pin away from the first half pin; the L-shaped pin is adapted to the rectangular slot and can move up and down in the rectangular slot; After the L-shaped pin is placed in the rectangular groove, the vertical section of the L-shaped pin enters the inner arc key groove, and its lower end is flush with the lower end of the rectangular groove, and the lower end of the L-shaped pin is supported by the auxiliary gasket.

2. The axial positioning structure for a full circle of self-locking blades according to claim 1, characterized in that: The main bodies of the first half pin and the second half pin are semi-cylindrical structures; the first pin crown is a semi-conical structure; the second pin crown is a long strip structure, the front-to-back length of which is equal to the diameter of the first pin crown, and the left-right width of which is smaller than the radius of the first pin crown; The sum of the thickness of the vertical section of the L-shaped pin and the left and right widths of the second pin crown is less than or equal to the radius of the first pin crown.

3. The axial positioning structure for a full circle of self-locking blades according to claim 2, characterized in that: The outer diameter of the main body of the first half pin and the second half pin is ψ; the height of the first pin crown and the second pin crown of the first half pin and the second half pin is A; the diameter of the first pin crown and the front-to-back length of the second pin crown are ф; The heights of the horizontal and vertical sections of the L-shaped pin are C and B respectively, its axial width is D, and its thickness is E. The ψ≈0.5ф, B=A, A+1.0MM≤C=≤A+4.0mm, D=0.5ф~1.0ф, and E=0.5ф.

4. The axial positioning structure for a full circle of self-locking blades according to claim 1, characterized in that: The axial center of the rectangular groove is consistent with the axial center of the back arc key groove; the axial position of the wheel rim pin hole is consistent with the axial position of the rectangular groove.

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