Flexible gasket for shaft end compression connection and connection system

Abstract

The invention discloses a flexible gasket for shaft end compression connection and a connection system. The flexible gasket comprises a gasket body, the section of the gasket body is S-shaped, termination contact surfaces are formed on the outer sides of two corner sections of the S-shaped gasket body, the two ends of the S-shaped gasket body extend out relative to the termination contact surfaces, and initial contact surfaces are formed at the two ends of the S-shaped gasket body. The connecting system comprises the threaded shaft and further comprises the flexible gasket, and the gasket body is arranged on the threaded shaft and located between the pressed piece and the pressing nut. The flexible gasket has the beneficial effects that the flexibility of the gasket is high, the flexibility of a traditional connection system can be improved by dozens of times to dozens of times, meanwhile, the elastic compression length of the flexible gasket can reach 3-4 mm, and large uncoordinated deformation of the connection system can be contained; the gasket is uniform in overall thickness, smooth in structural transition, S-shaped and free of obvious stress concentration when pressed; the gasket is provided with a termination contact surface, can bear large extrusion force, and allows the compression nut connecting system to have high initial pretightening force.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engine rotor compression nut coupling system, and particularly relates to a flexible gasket for shaft end compression coupling and a coupling system, which can increase the flexibility of the coupling system and ensure that the coupling system always maintains sufficient pre-tightening force in a complex working environment. BACKGROUND

[0002] Various parts exist on the engine rotor shaft, such as bearing inner (outer) ring, runway, spacer block, bevel gear shaft, wheel disc shaft neck, sleeve tooth shaft and the like, and the coupling of each part is usually compressed together by the shaft end nut. The compression force of the shaft end nut is generally tens of thousands of newtons to hundreds of thousands of newtons, and the flexibility grade of the shaft end nut coupling system is generally 10 -5 mm / N~10 -6 mm / N, that is, the deformation coordination of every 0.1mm will affect tens of thousands of newtons of nut compression force.

[0003] There are many factors causing deformation in the working process of the coupling system, such as thermal expansion deformation, centrifugal Poisson effect, nut vibration loosening, working axial force load and the like, which can all cause the pre-tightening force of the coupling system to decrease greatly or even to be zero. Increasing the flexibility of the system is one of the solutions to the above problems, and the greater the flexibility of the system, the smaller the influence of the coordinated deformation of the system on the pre-tightening force. SUMMARY

[0004] The application aims to provide a flexible gasket for shaft end compression coupling and a coupling system, which can increase the flexibility of the compression nut coupling system and reduce the influence of the working environment on the pre-tightening force of the nut coupling system.

[0005] The application achieves the above-mentioned purpose through the following technical scheme. A flexible gasket for shaft end compression coupling, comprising a gasket body, the cross section of the gasket body is S-shaped, the outer side of the two corner segments of the S-shaped gasket body forms a terminal contact surface, the two ends of the S-shaped gasket body extend relative to the terminal contact surface, and the two ends of the S-shaped gasket body form an initial contact surface.

[0006] Further, the S-shaped gasket body comprises flat layer segments and corner segments, the flat layer segments are three inner, middle and outer layers parallel to each other, the corner segments are between the adjacent two flat layer segments, and the corner segments are 180° corners.

[0007] Further, the elastic modulus of the gasket body is 90~110GPa, and the yield strength is not less than 1000MPa.

[0008] Further, the gasket body is made of titanium alloy material.

[0009] Further, the flexibility of the gasket body is 10 -4 ~10-5 mm / N.

[0010] Further, the thickness of the gasket body is h, the distance between the single-sided initial contact surface and the terminal contact surface is a, the distance between the two adjacent flat sections is 3h, and the length of the gasket body axis is 10h+2a.

[0011] Further, h is 1.5-2mm, and a is 1.5-2mm.

[0012] Further, the distance between the two-sided initial contact surface and the terminal contact surface is the same.

[0013] A coupling system of a shaft end compression coupling, comprising a threaded shaft, a compression part and a compression nut arranged on the threaded shaft, and a flexible gasket of a shaft end compression coupling as described above, wherein the gasket body is arranged on the threaded shaft and located between the compression part and the compression nut. Before assembly, the compression end surface of the compression part is in contact with the initial contact surface at one end of the gasket body, and the compression end surface of the compression nut is in contact with the initial contact surface at the other end of the gasket body. During assembly, the compression nut is gradually tightened. After assembly, the compression end surface of the compression part is in contact with the initial contact surface and the terminal contact surface at one end of the gasket body, and the compression end surface of the compression nut is in contact with the initial contact surface and the terminal contact surface at the other end of the gasket body.

[0014] Further, after assembly, F=2a / s, wherein F is the pre-tightening force of the compression nut, a is the distance between the single-sided initial contact surface and the terminal contact surface, and s is the flexibility of the gasket body.

[0015] The beneficial effects of the present application are: (1) The gasket has high flexibility, which can increase the flexibility of the traditional coupling system by tens to hundreds of times, and the elastic compression length of the flexible gasket can reach 3-4mm, which can accommodate large incoordination deformation of the coupling system.

[0016] (2) The gasket has uniform overall thickness, smooth structure transition, and S-shaped structure, and has no obvious stress concentration under pressure.

[0017] (3) The gasket has a terminal contact surface, can withstand a large extrusion force, and allows the compression nut coupling system to have a high initial pre-tightening force.

[0018] The foregoing main scheme of the present application and each further selected scheme thereof can be freely combined to form multiple schemes, all of which are the schemes that can be adopted and claimed by the present application; and the present application can also be freely combined between each non-conflicting selection and between and other selections. A person skilled in the art can understand that there are multiple combinations according to the prior art and common knowledge after understanding the schemes of the present application, all of which are the technical schemes claimed by the present application, and are not listed here. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 is a structural schematic diagram of the present application.

[0020] Fig. 2 is a structural schematic diagram of the present application before assembly.

[0021] Fig. 3 is a structural schematic diagram of the present application after assembly.

[0022] In the figure: 1 - gasket body, 2 - threaded shaft, 3 - compressed part, 4 - compression nut, 5 - initial contact surface, 6 - terminal contact surface. DETAILED DESCRIPTION

[0023] The following non-limiting examples are used to illustrate the present application.

[0024] Example 1 Reference Figs. 1-3 As shown, a flexible gasket of a shaft end compression coupling includes a gasket body 1.

[0025] The gasket body 1 is a circular ring structure, and its cross section is S-shaped. The outer side of the two corner sections of the S-shaped gasket body 1 forms a terminal contact surface 6, and the two ends of the S-shaped gasket body 1 protrude relative to the terminal contact surface 6, and the two ends of the S-shaped gasket body 1 form an initial contact surface 5.

[0026] The two ends of the S-shaped gasket body 1 protrude relative to the corner sections, cooperate with the bending deformation of the corner sections, facilitate the pre-compression of the gasket body 1 before assembly, and after assembly is completed, the two ends of the S-shaped gasket body 1 are compressed and retracted, so that the overall gasket body 1 performs a supporting action, and the flexibility is provided through the S-shaped structure. There are two arrangement forms of the S-shaped gasket body 1, taking the middle shaft body as a reference, the upper cross section is S-shaped, then the lower cross section is inverted S-shaped, or the upper cross section is inverted S-shaped, and the lower cross section is S-shaped.

[0027] The S-shaped gasket body 1 includes integral flat sections and corner sections, the flat sections are three layers of inner, middle and outer layers parallel to each other, mainly used for support, and the end portions of the inner and outer layers of the flat sections are also used for contact and fit due to the initial contact surface 5. The corner sections between the adjacent two flat sections are 180° corners, preferably U-shaped corners, mainly used for transition deformation, and also contact and fit through the terminal contact surface 6.

[0028] The material of the gasket body 1 is preferably selected from a material with high yield strength and low elastic modulus. The elastic modulus of the gasket body 1 is 90-110 GPa, preferably 100 GPa, and the yield strength is not less than 1000 MPa. The gasket body 1 is preferably made of titanium alloy, and the flexibility of the gasket body 1 is 10 -4 ~10 -5 mm / N.

[0029] The distance between the two initial contact surfaces 5 and the terminal contact surfaces 6 is the same, and the distance between the single initial contact surface 5 and the terminal contact surface 6 is a (single compressible size). The distance between the single initial contact surface 5 and the terminal contact surface 6 is half of the gasket assembly compression size.

[0030] The thickness of the gasket body 1 is h. Taking a compression nut with a thread parameter of M100 as an example, the thickness h of the gasket body 1 is 1.5-2 mm. The distance a between the single initial contact surface 5 and the terminal contact surface 6 is 1.5-2 mm. The distance c between the two adjacent flat sections is 3h, i.e. c is 4.5-6 mm. The axial length L of the gasket body 1 is 10h+2a, i.e. L is 18-24 mm.

[0031] Regarding the gasket size design, under the premise of ensuring the strength and flexibility of the gasket, the axial size L of the gasket is as small as possible, and the single compressible size a is as large as possible. The larger a is, the larger the deformation that the coupling system can tolerate, which is beneficial to the reliability of the coupling, but the stress after assembly is also larger, and the value of a is limited by the yield strength of the material. The larger L is, the smaller the assembly stress is, and a larger L value is beneficial to the design of the compression size a, but the L value is limited by the structure design space.

[0032] Example 2 Referring to Figs. 1-3 Fig. 2, a shaft end compression coupling coupling system includes a threaded shaft 2, a compressed part 3 and a compression nut 4, and also includes the flexible gasket of the shaft end compression coupling of example 1. The threaded shaft 2 is sleeved with the compressed part 3 and the compression nut 4. One side of the compressed part 3 is clamped and limited by the shaft shoulder of the threaded shaft, and the compression nut 4 is screwed on the threaded section of the threaded shaft 2.

[0033] The gasket body 1 is sleeved on the threaded shaft 2 and located between the compressed part 3 and the compression nut 4. A gasket with larger flexibility is added to the compression nut coupling system to improve the flexibility of the system, and the flexibility of the gasket is generally 5-10 times that of the original coupling system.

[0034] Referring to Fig. 2 Fig. 3, before assembly, the compressed end surface of the compressed part 3 is in contact with the initial contact surface 5 at one end of the gasket body 1, and the compression end surface of the compression nut 4 is in contact with the initial contact surface 5 at the other end of the gasket body 1.

[0035] During assembly, the compression nut 4 is gradually tightened, the two ends of the gasket body 1 are pressed by the compression nut 4 and the pressing part 3, and the S-shaped two ends are gradually compressed. When the nut and the pressing part are in contact with the terminal contact surface, the gasket cannot be compressed any more, and the assembly is completed.

[0036] Reference Fig. 3 As shown, after assembly, the pressed end face of the pressing part 3 is in contact with the initial contact surface 5 and the terminal contact surface 6 of one end of the gasket body 1, and the compression end face of the compression nut 4 is in contact with the initial contact surface 5 and the terminal contact surface 6 of the other end of the gasket body 1. At this time, the gasket flexibility is reduced to 10 -5 mm / N, and the compression deformation amount significantly decreases with the increase of the pre-tightening force.

[0037] After assembly, F=2a / s, where F is the pre-tightening force of the compression nut 4, a is the distance between the single-sided initial contact surface 5 and the terminal contact surface 6, and s is the flexibility of the gasket body 1.

[0038] The implementation steps of the flexible gasket design are as follows: 1. Evaluate the uncoordinated deformation amount b of the structure, considering thermal deformation, rotor centrifugal Poisson effect, allowable nut back-off angle, working axial force, etc.

[0039] 2. Determine the effective compression force T required by the nut coupling system according to the working load.

[0040] 3. Adjust the thickness, overall size, compression size and material of the gasket to design the characteristic parameters of the flexible gasket: pre-tightening force F, compressible size 2a, overall axial size L, flexibility s and material yield strength.

[0041] 4. The above parameters meet the following requirements: a. The maximum equivalent stress of the gasket under the action of the pre-tightening force F is less than the yield strength of the material; b. The overall axial size L is allowed by the structure; c. After the uncoordinated deformation of the structure, the nut coupling system still has sufficient compression force, i.e. F-(2a-b)*s≥T.

[0042] The foregoing basic examples and each further selected example of the present application can be freely combined to form a plurality of embodiments, all of which are embodiments that can be used and claimed by the present application. In the present application, each selected example can be arbitrarily combined with any basic example and selected example.

[0043] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A flexible gasket for shaft end compression connection, comprising a gasket body (1), characterized in that: The cross section of the gasket body (1) is S-shaped, and the outer sides of the two corner sections of the S-shape of the gasket body (1) form a terminal contact surface (6), and the two ends of the S-shape of the gasket body (1) extend relative to the terminal contact surface (6), and the two ends of the S-shape of the gasket body (1) form an initial contact surface (5).

2. The flexible washer for shaft end compression connection according to claim 1, characterized in that: The washer body (1) is S-shaped and comprises a flat section and a corner section. The flat section is composed of three mutually parallel layers: inner, middle and outer layers. The corner section is between two adjacent flat sections, and the corner section is a 180° angle.

3. The flexible washer for shaft end compression connection according to claim 1 or 2, characterized in that: The elastic modulus of the gasket body (1) is 90-110 GPa, and the yield strength is not less than 1000 MPa.

4. The flexible washer for shaft end compression connection according to claim 3, characterized in that: The washer body (1) is made of titanium alloy.

5. The flexible washer for shaft end compression connection according to claim 1, characterized in that: The flexibility of the washer body (1) is 10 -4 ~10 -5 mm / N.

6. The flexible washer for shaft end compression connection according to claim 1, characterized in that: The thickness of the gasket body (1) is h, the distance between the single-sided initial contact surface (5) and the terminal contact surface (6) is a, the distance between two adjacent flat sections is 3h, and the axial length of the gasket body (1) is 10h+2a.

7. The flexible washer for shaft end compression connection according to claim 6, characterized in that: h is 1.5~2mm, a is 1.5~2mm.

8. The flexible washer for shaft end compression connection according to claim 1, characterized in that: The distances between the initial contact surface (5) and the terminal contact surface (6) on both sides are the same.

9. A coupling system for a shaft end compression connection, comprising a threaded shaft (2), a compressed member (3) and a compression nut (4) being provided on the threaded shaft (2), characterized in that: It also includes a flexible washer for shaft end compression connection according to any one of claims 1 to 8, wherein the washer body (1) is provided on the threaded shaft (2) and is located between the compressed part (3) and the compression nut (4); Before assembly, the pressed end surface of the pressed part (3) is in contact with the initial contact surface (5) at one end of the washer body (1), and the pressing end surface of the clamping nut (4) is in contact with the initial contact surface (5) at the other end of the washer body (1); During assembly, gradually tighten the compression nut (4); After assembly, the compressed end surface of the compressed part (3) contacts and fits with the initial contact surface (5) and the terminal contact surface (6) at one end of the washer body (1), and the compression end surface of the compression nut (4) contacts and fits with the initial contact surface (5) and the terminal contact surface (6) at the other end of the washer body (1).

10. The shaft end compression connection system according to claim 9, characterized in that: After assembly, F = 2a / s, where F is the preload force of the compression nut (4), a is the distance a between the initial contact surface (5) and the final contact surface (6) on one side, and s is the flexibility of the washer body (1).

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