Adaptively morphing coordinated turbine guide vane support arrangement

Abstract

The adaptive deformation coordination turbine guide vane support layout structure of the present application is provided with a first one-way floating support on the front mounting edge of the outer edge plate of the guide vane and a second one-way floating support on the rear mounting edge of the outer edge plate of the guide vane, wherein one end of the first one-way floating support is movably connected with the flame tube of the combustion chamber, and the front mounting edge of the outer edge plate of the guide vane is matched with the other end of the first one-way floating support in a small gap mode; one end of the second one-way floating support is connected with the outer force bearing casing through a flexible ring, and the rear mounting edge of the outer edge plate of the guide vane is embedded into the other end of the second one-way floating support, which has the characteristics of strong deformation coordination ability, high stability and high reliability of the force transmission path.

Description

Technical Field

[0001] This invention relates to the technical field of turbine stator structures for aero-engines, and more particularly to a turbine guide support layout structure with adaptive deformation coordination. Background Technology

[0002] Currently, engine turbine guide vanes are primarily subjected to circumferential forces and thermal stresses generated by the impact of combustion gases during operation. Their inlet temperatures can reach 1800K–2200K, and this large temperature difference leads to significant and complex thermal deformation. Under hot conditions, thermal expansion occurs unevenly in the axial, circumferential, and radial directions; simultaneously, the guide vane support structure also experiences inconsistent dimensional deformation in the high-temperature environment. Therefore, the layout of high-pressure turbine guide vanes must possess sufficient deformation coordination capabilities, while also controlling the stability and reliability of the high-pressure turbine guide vanes during operation and limiting the guide vane's degrees of freedom sufficiently. This makes its cold and hot state positioning design quite challenging.

[0003] The existing publicly disclosed turbine guide seal structure, publication number "CN 203114428 U", is entitled "A Gas Turbine Engine Seal Hanger Connection Structure". It mainly describes its connection and sealing function, but only involves a local structure and does not involve the overall layout, resulting in low performance.

[0004] The existing publicly disclosed spring-loaded sealing structure of “CN206647140U” and the pin connection with adjusting plate of “CN206477888U” can better adapt to blade floating. Both are local structures that ensure part of the free expansion, but do not involve the overall layout and provide insufficient guidance for the overall design of turbine stators.

[0005] In summary, the existing layout structure has low deformation coordination capability and poor stability of force transmission path. Summary of the Invention

[0006] In view of this, the present invention provides an adaptive deformation coordination turbine guide support layout structure, which has the characteristics of strong deformation coordination ability, high stability of force transmission path and high reliability.

[0007] An adaptive deformation-coordinated turbine guide vane support layout structure is disclosed, suitable for the positioning and sealing of the turbine stator. The stator includes guide vanes and inner and outer load-bearing casings. A first unidirectional floating bracket is provided on the front mounting edge of the outer edge plate of the guide vane, and a second unidirectional floating bracket is provided on the rear mounting edge of the outer edge plate of the guide vane.

[0008] One end of the first unidirectional floating bracket is movably connected to the combustion chamber flame tube, and the front mounting edge of the outer edge plate of the guide vane is fitted with the other end of the first unidirectional floating bracket with a small gap.

[0009] One end of the second unidirectional floating bracket is connected to the outer load-bearing casing via a flexible ring. The rear mounting edge of the guide vane's outer edge plate is embedded in the other end of the second unidirectional floating bracket. When the deformation of the inner load-bearing casing is equal to the deformation of the outer load-bearing casing, the degrees of freedom of the first and second unidirectional floating brackets relative to the guide vane are restricted to "0". When the deformation of the inner load-bearing casing is less than the deformation of the outer load-bearing casing, the degrees of freedom of the first unidirectional floating bracket relative to the guide vane are restricted to "1", and the degrees of freedom of the second unidirectional floating bracket relative to the guide vane are restricted to "0". When the deformation of the inner load-bearing casing is greater than the deformation of the outer load-bearing casing, the degrees of freedom of the first unidirectional floating bracket relative to the guide vane are restricted to "0", and the degrees of freedom of the second unidirectional floating bracket relative to the guide vane are restricted to "1". Furthermore, when the guide vane is rotated by aerodynamic force at XOZ, the degrees of freedom of the second unidirectional floating bracket relative to the guide vane are restricted to "1".

[0010] Beneficial effects

[0011] Through the cooperation between multiple compensation structures, the load distribution on the guide vane mounting edge is uniform, and it is almost only subject to aerodynamic loads. The local stress is small, the deformation coordination ability is strong, and it is not affected by the forced displacement caused by the deformation difference between the inside and outside of the stator or the thermal deformation of the blade itself. That is, it is not affected by the support reaction force, which is beneficial to the blade life. Furthermore, the guide vane support point always maintains high stability and reliability, and there will be no loss of freedom of degree of freedom, ensuring reliable force transmission. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 For turbine guide support layout;

[0014] Figure 2 For turbine guide support structure;

[0015] Figure 3 This is a schematic diagram of the second unidirectional floating support;

[0016] Figure 4 This is a schematic diagram of the first unidirectional floating support;

[0017] Figure 5 It is a bidirectional floating support, in which,

[0018] 1. Hinge bracket; 2. Second unidirectional floating bracket; 3. First unidirectional floating bracket; 4. Bidirectional floating bracket; 5. Guide vane; 6. Outer load-bearing housing; 102. Nut; 103. Inner load-bearing housing; 104. Bolt; 105. Baffle; 106. Sealing ring; 201. Second sealing rope; 202. Flexible support ring; 301. Sliding ring; 302. Flame tube outer ring; 303. First sealing rope; 501. Front mounting edge of the inner edge plate of the guide vane; 502. Rear mounting edge of the inner edge plate of the guide vane; 503. Front mounting edge of the outer edge plate of the guide vane; 504. Rear mounting edge of the outer edge plate of the guide vane; 700. First mating piece; 701. First groove; 800. Second mating piece; 801. Third groove; 900. Second groove. Detailed Implementation

[0019] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0020] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The drawings only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that these aspects can be practiced without these specific details.

[0024] See Figures 1 to 5 The adaptive deformation-coordinated turbine guide vane support layout structure shown is suitable for the positioning and sealing of the turbine stator. The stator includes guide vanes 5, an inner load-bearing casing 103, and an outer load-bearing casing 6. An improvement of this invention is that a first one-way floating bracket 3 is provided on the front mounting edge 503 of the outer edge plate of the guide vane, and a second one-way floating bracket 2 is provided on the rear mounting edge 504 of the outer edge plate of the guide vane.

[0025] One end of the first one-way floating support 3 is axially connected to the combustion chamber flame tube. The front mounting edge 503 of the outer edge plate of the guide vane is fitted with the other end of the first one-way floating support 3 with a small gap. One end of the second one-way floating support 2 is connected to the outer load-bearing casing 6 through a flexible ring. The rear mounting edge 504 of the outer edge plate of the guide vane is embedded in the other end of the second one-way floating support 2.

[0026] The cooperation between the first unidirectional floating support 3 and the second unidirectional floating support 2 restricts the degree of freedom of the guide vane 5 to 0-1 when a displacement difference occurs between the inner and outer load-bearing casings 6. 0 represents that the deformation of the inner load-bearing casing 103 is greater than that of the outer load-bearing casing 6, and 1 represents that the deformation of the inner load-bearing casing 103 is less than that of the outer load-bearing casing 6. Specifically:

[0027] When the deformation of the inner load-bearing casing 103 is equal to the deformation of the outer load-bearing casing 6, the degree of freedom of the first unidirectional floating bracket 3 and the second unidirectional floating bracket 2 relative to the guide vane 5 is restricted to 0.

[0028] When the deformation of the inner bearing casing 103 is less than the deformation of the outer bearing casing 6, the first one-way floating bracket 3 restricts the degree of freedom of the guide vane 5 to "1", and the second one-way floating bracket 2 restricts the degree of freedom of the guide vane 5 to "0" (no degree of freedom is restricted). When the guide vane is rotated by aerodynamic force according to XOZ, the second one-way floating bracket restricts the degree of freedom of the guide vane to "1".

[0029] When the deformation of the inner load-bearing casing 103 is greater than the deformation of the outer load-bearing casing 6, the first unidirectional floating support 3 restricts the degree of freedom of the guide vane 5 to 0, and the second unidirectional floating support 2 restricts the degree of freedom of the guide vane 5 to 1 (axial restriction).

[0030] As a specific implementation method provided in this case, such as Figure 2 As shown, in order to further limit and compensate the inner edge plate of the guide vane 5, a bidirectional floating bracket 4 is provided on the front mounting edge 501 of the inner edge plate of the guide vane. One end of the bidirectional floating bracket 4 is movably connected to the combustion chamber (a groove is opened at the corresponding position of the combustion chamber, and the connection is sufficient to ensure that it does not detach from the combustion chamber). The other end of the bidirectional floating bracket 4 is movably embedded in the front mounting edge 501 of the inner edge plate of the guide vane. The bidirectional floating bracket 4 restricts the degree of freedom of the guide vane 5 to 0 (no degree of freedom is restricted). The bidirectional floating bracket 4 is an arc-shaped structure with a groove. The front mounting edge 501 of the inner edge plate of the guide vane is movably installed in the groove of the bidirectional floating bracket 4.

[0031] A hinge bracket 1 is provided on the rear mounting edge 502 of the inner edge plate of the guide vane. One end of the hinge bracket 1 is fixed to the inner casing, and the other end is hinged to the rear mounting edge 502 of the inner edge plate of the guide vane, thereby restricting the degrees of freedom of the guide vane 5, including the restriction of the three degrees of freedom of axial, radial and rotation. Rotation refers to the restriction of rotation in the XOY (rotation around the Z axis of the casing) direction.

[0032] As a specific implementation method provided in this case, such as Figure 4 As shown, the first unidirectional floating support 3 is illustrated by example. The first unidirectional floating support 3 includes a sliding ring 301, an outer ring 302 of the flame tube, and a first sealing rope 303 to be elastically attached.

[0033] The sliding ring 301 is movably fitted onto the outer ring 302 of the flame tube, and an elastic first sealing rope 303 is provided on the outer ring 302 of the flame tube to ensure the sealing performance between the outer ring of the flame tube and the sliding ring 301. The first sealing rope 303 is placed between the sliding ring 301 and the outer ring 302 of the flame tube. The first sealing rope 303 is used to adjust the first preset gap between the sliding ring 301 and the front mounting edge 503 of the outer edge plate of the guide vane to always remain zero, and to ensure the sealing performance between the sliding ring 301 and the front mounting edge 503 of the outer edge plate of the guide vane. Because there is a deformation difference between the inner and outer load-bearing casings 6, the front mounting edge 503 of the outer edge plate of the guide vane needs to move. By using the sliding ring 301 as an adjusting element, the front mounting edge 503 of the outer edge plate of the guide vane is converted into axial compression of the sealing rope, thus maintaining the sealing performance of the first unidirectional floating bracket 3.

[0034] As a specific implementation method provided in this case, such as Figure 3As shown, the second unidirectional floating support 2 includes a second sealing rope 201 and a flexible support ring 202, wherein,

[0035] One end of the flexible support ring 202 is installed on the outer load-bearing housing 6, and the other end is provided with a first docking piece 700 with a first groove 701. The first docking piece 700 and the outer load-bearing housing 6 have a second preset gap. The second sealing rope 201 is installed in the first groove 701, and the rear mounting edge 504 of the outer edge plate of the guide vane is embedded in the first groove 701 in a radially movable manner (limited in the axial direction).

[0036] When there is a deformation difference between the inner and outer load-bearing casings 6, the rear mounting edge 504 of the outer edge plate of the guide vane causes the flexible support ring 202 to deform, causing the first docking piece 700 to contact the outer load-bearing casing 6, at which point the gap becomes zero.

[0037] As a specific implementation provided in this case, the flame tube is provided with a second groove 900, and the bidirectional floating support 4 includes a second docking member 800 with a third groove 801. One end of the second docking member 800 can slide freely in the second groove 900, and the other end is provided with a third groove 801. The front mounting edge 501 of the inner edge plate of the guide vane is radially movable and embedded in the third groove 801 (the guide vane 5 is axially limited).

[0038] When there is a deformation difference between the inner and outer load-bearing casings 6, the front mounting edge 501 of the inner edge plate of the guide vane drives one end of the second docking piece 800 to slide in the second groove 900, which can ensure that the deformation of the front mounting edge of the inner edge plate of the guide vane is coordinated with that of the flame tube.

[0039] As a specific implementation method provided in this case, such as Figure 5 As shown, the hinge bracket 1 includes an inner support and a baffle 105 arranged in a ring-shaped stepped structure, wherein,

[0040] One end of the inner support is fixed to the rear mounting edge 502 of the inner edge plate of the guide vane by a pin (holes are opened at corresponding positions and the pins are inserted for fixing), and the other end is sealed to the inner load-bearing casing 103 by bolts 104 and nuts 102. For example, the sealing connection is achieved by setting an elastic sealing plate, and / or a protective baffle 105 is provided on the inner ring surface of the inner load-bearing casing 103. The baffle 105 restricts the axial displacement of the blade. This hinge structure does not completely restrict the blade's XOZ rotation and slight displacement in the X direction, and is used to accommodate the axial deformation difference between the inner and outer casings. Furthermore, a sealing ring 106 is provided between the baffle 105 and the rear mounting edge 502 of the inner edge plate of the guide vane to ensure sealing by using elastic deformation.

[0041] Secondly, an adaptive deformation-coordinated turbine guide vane support layout method is provided, using the adaptive deformation-coordinated turbine guide vane support layout structure as described in part or in whole above. This includes a design method for a first preset gap and a second preset gap. The X direction is defined as the guide vane along the airflow direction (axial direction), the Z direction as the guide vane radial direction, and the Y direction as the guide vane tangential direction. Hereafter, X, Y, and Z are used to describe the deformation or movement direction of the part, and all dimensions are in millimeters (mm). The method includes the following steps:

[0042] S1. Based on the strength calculation of the turbine stator, determine the deformation in the X and Z directions of the turbine inner bearing casing under working conditions 1 to n, where n is related to the turbine model.

[0043] DX 内 The deformation of the turbine's internal load-bearing casing in the X direction is denoted as DX. 内 1-DX 内 n,DZ 内 The deformation of the turbine's internal load-bearing casing in the Z direction is denoted as DZ. 内 1-DZ 内 n,DX 外 The deformation of the turbine's external load-bearing casing in the X direction is denoted as DX. 外 1-DX 外 n,DZ 外 The deformation of the turbine external bearing casing in the Z direction is denoted as DZ. 外 1-DZ 外 n;

[0044] The difference in deformation between the inner and outer load-bearing casings in the X and Y directions is Δ. 机匣 The difference Δ is determined by the difference method. 机匣 The extreme values;

[0045]

[0046] S2. Based on the strength calculation of the turbine guide vane, determine the deformation in the X and Z directions of the vane under operating conditions 1-n, where...

[0047] DX b The deformation of the guide vane in the X direction is denoted as DX. b 1-DX b n, DZ b The deformation of the guide vane in the Z direction is denoted as DZ. b 1-DZ b n;DZ b 1-DZ b n satisfies that the radial clearance between the first groove and the outer edge of the guide vane mounting plate 502 is greater than DZ. b The extreme values;

[0048] S3. Determine the radial height difference H between the hinge bracket and the sliding bracket based on the adaptive deformation coordinated turbine guide support layout structure.

[0049] S4, via Δ 机匣 and DX b The first preset gap Ac1 and the second preset gap Ac2 are allocated, and the allocation expression is H·tan1.5≥Ac1+Ac2-(Δ 机匣 +DX b )≥0, and ensure that the blade assembly is vertical;

[0050] Δ 机匣 When taking the extreme value shown, it is necessary to satisfy Ac1 + Ac2 - (Δ 机匣 +DX b ) = 0.

[0051] The type of bracket selected above can be replaced by a functionally corresponding part to achieve the same function. In traditional processes, different materials can be used to make different parts, and these parts can replace the brackets indicated in this invention.

[0052] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An adaptive deformation-coordinated turbine guide vane support layout structure, suitable for the positioning and sealing of the turbine stator, the stator comprising guide vanes and inner and outer load-bearing casings, characterized in that, A first unidirectional floating bracket is provided on the front mounting edge of the outer edge plate of the guide vane, and a second unidirectional floating bracket is provided on the rear mounting edge of the outer edge plate of the guide vane. One end of the first unidirectional floating support is movably connected to the combustion chamber flame tube, and the front mounting edge of the outer edge plate of the guide vane is fitted with the other end of the first unidirectional floating support with a small gap. One end of the second unidirectional floating support is connected to the outer load-bearing casing through a flexible ring, and the rear mounting edge of the outer edge plate of the guide vane is embedded in the other end of the second unidirectional floating support. When the deformation of the inner load-bearing casing is equal to the deformation of the outer load-bearing casing, the degree of freedom of the first and second unidirectional floating supports relative to the guide vane is restricted to "0". When the deformation of the inner load-bearing casing is less than the deformation of the outer load-bearing casing, the degree of freedom of the first unidirectional floating support relative to the guide vane is restricted to "1", and the degree of freedom of the second unidirectional floating support relative to the guide vane is restricted to "0". When the deformation of the inner load-bearing casing is greater than the deformation of the outer load-bearing casing, the degree of freedom of the first unidirectional floating support relative to the guide vane is restricted to "0", and the degree of freedom of the second unidirectional floating support relative to the guide vane is restricted to "1". When the guide vane is rotated by aerodynamic force in an XOZ direction, the second unidirectional floating support restricts the degree of freedom of the guide vane to "1"; the X direction is defined as the direction of the guide vane along the airflow, the Z direction is the radial direction of the guide vane, and the Y direction is the tangential direction of the guide vane, where a degree of freedom restriction of "1" indicates axial restriction; A bidirectional floating bracket is provided on the front mounting edge of the inner edge plate of the guide vane. One end of the bidirectional floating bracket overlaps the combustion chamber, and the front mounting edge of the inner edge plate of the guide vane is movably embedded into the other end of the bidirectional floating bracket. The bidirectional floating bracket always restricts the degree of freedom of the guide vane to "0". A hinge bracket is provided on the rear mounting edge of the inner edge plate of the guide vane. One end of the hinge bracket is fixed to the inner casing, and the other end is hinged to the rear mounting edge of the inner edge plate of the guide vane, which restricts the degree of freedom of the guide vane, including the restriction of the three degrees of freedom of axial, radial and circumferential rotation.

2. The adaptive deformation-coordinated turbine guide support layout structure according to claim 1, characterized in that, The first unidirectional floating support includes a sliding ring, an outer ring of the flame tube, and a first sealing rope, wherein, The sliding ring is movably fitted onto the outer ring of the flame tube, and a first sealing rope is provided on the outer ring of the flame tube to ensure the sealing performance between the outer ring of the flame tube and the sliding ring. The first sealing rope is elastic and can adjust the first preset gap between the sliding ring and the front mounting edge of the outer edge plate of the guide vane to always remain zero, thus ensuring the sealing performance between the sliding ring and the front mounting edge of the outer edge plate of the guide vane.

3. The adaptive deformation-coordinated turbine guide support layout structure according to claim 2, characterized in that, The second unidirectional floating support includes a second sealing rope and a flexible support ring, wherein, One end of the flexible support ring is installed on the outer load-bearing housing, and the other end is provided with a first docking piece with a first groove. The first docking piece and the outer load-bearing housing have a second preset gap. The second sealing rope is installed in the first groove, and the rear mounting edge of the outer edge plate of the guide vane is embedded in the first groove in a radially movable manner. When there is a deformation difference between the inner and outer load-bearing casings, the rear mounting edge of the outer edge plate of the guide vane causes the flexible support ring to deform, which in turn causes the first docking piece to contact the outer load-bearing casing in order to transfer the blade load.

4. The adaptive deformation-coordinated turbine guide support layout structure according to claim 3, wherein the flame tube is provided with a second groove, characterized in that, The bidirectional floating support includes a second docking member with a third groove. One end of the second docking member can slide freely in the second groove, and the other end is provided with the third groove. The front mounting edge portion of the inner edge plate of the guide vane is radially movable and embedded in the third groove. When there is a deformation difference between the inner and outer load-bearing casings, the front mounting edge of the inner edge plate of the guide vane drives one end of the second docking piece to slide in the second groove, which can ensure that the deformation of the front mounting edge of the inner edge plate of the guide vane is coordinated with that of the flame tube.

5. The adaptive deformation-coordinated turbine guide support layout structure according to claim 4, characterized in that, The hinge bracket includes an inner support arranged in a ring-shaped stepped structure, wherein... One end of the inner support is fixed to the rear mounting edge of the inner edge plate of the guide vane by a pin, and the other end is sealed to the inner load-bearing casing, and / or a baffle is provided on the inner ring surface of the inner load-bearing casing.

6. A method for adaptive deformation-coordinated turbine guide support layout, characterized in that, The turbine guide vane support layout structure with adaptive deformation coordination as described in claim 5 is characterized by including a design method for a first preset gap and a second preset gap, defining the X direction as the guide vane along the airflow direction, the Z direction as the guide vane radial direction, and the Y direction as the guide vane tangential direction, including the following steps: S1. Based on the strength calculation of the turbine stator, determine the deformation in the X and Z directions of the turbine inner bearing casing under working conditions 1 to n, where n is related to the turbine model. DX 内 The deformation of the turbine's internal load-bearing casing in the X direction is denoted as DX. 内 1-DX 内 n,DZ 内 The deformation of the turbine's internal load-bearing casing in the Z direction is denoted as DZ. 内 1-DZ 内 n,DX 外 The deformation of the turbine's external load-bearing casing in the X direction is denoted as DX. 外 1-DX 外 n,DZ 外 The deformation of the turbine external bearing casing in the Z direction is denoted as DZ. 外 1-DZ 外 n; The difference in deformation between the inner and outer load-bearing casings in the X and Z directions is Δ. 机匣 The difference Δ is determined by the difference method. 机匣 The extreme values; ; S2. Based on the strength calculation of the turbine guide vane, determine the deformation in the X and Z directions of the vane under operating conditions 1-n, where... DX b The deformation of the guide vane in the X direction is denoted as DX. b 1-DX b n, DZ b The deformation of the guide vane in the Z direction is denoted as DZ. b 1-DZ b n;DZ b 1-DZ b n satisfies that the radial clearance between the first groove and the rear mounting edge of the guide vane's outer edge plate is greater than DZ. b The extreme values; S3. Determine the radial height difference H between the hinge bracket and the sliding bracket based on the adaptive deformation coordinated turbine guide support layout structure. S4, via Δ 机匣 and DX b The first preset gap Ac1 and the second preset gap Ac2 are allocated, and the allocation expression is H•tan1.5≥Ac1+Ac2-(Δ 机匣 +DX b )≥0, and ensure that the blade assembly is vertical; Δ 机匣 When taking the extreme value shown, it is necessary to satisfy Ac1 + Ac2 - (Δ) 机匣 +DX b =0.

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