Angle self-compensation tooling for assembling aircraft variable-thickness composite parts and use method thereof

Abstract

The present application belongs to the technical field of aircraft unequal-thickness composite part assembly, and relates to an aircraft unequal-thickness composite part assembly angle self-compensation tool and a use method. When a conventional bolt connection is used on a component with uneven assembly sandwich thickness, local dimpling or the use of an inclined washer, a spherical washer or the like is required for compensation, which can damage the composite material structure, weaken the body strength, and increase the parallel bevel force on the surface of the component. The tool can self-adaptively adjust the internal structure to ensure that only the clamping force of the nut is applied to the surface of the part, and the surface of the composite component is not damaged by dimpling. The tool can adjust the parameters of each bolt by adjusting the camber, easily realize angle self-adaptive adjustment connection within a range of 30°, and has a wider application range.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft unequal-thickness composite part assembly, and relates to an aircraft unequal-thickness composite part assembly angle self-compensation tool and a use method. BACKGROUND

[0002] Composite materials have excellent mechanical properties, such as light weight, high strength, good mechanical properties, high heat resistance and high corrosion resistance. For example, T-1000 carbon fiber has a tensile strength of 7000 MPa at a density of less than 2 g / cm 2 , and is widely used in aerospace products. Composite materials are formed by laying up pre-impregnated materials, and their anisotropic characteristics determine that the in-plane strength of the material is greater than the interlaminar strength, causing the component to easily warp and deform. At the same time, the thickness size deviation of the composite part is large due to the influence of manufacturing process factors such as the number of plies and curing forming pressure. During the assembly process of groups / components, the warping deformation and thickness size change of the composite part cause the assembly gap of the composite material and other parts to be produced, and also cause the thickness of the assembly interlayer to be uneven. The assembly gap can be eliminated through measurement and compensation process, but the uneven thickness of the assembly interlayer causes the local surface of the fastener at the connection to have an included angle, and the conventional fastener cannot simultaneously ensure that the head and tail of the fastener are tightly attached to the two surfaces of the assembly interlayer, thereby causing the composite part to be unevenly stressed and causing delamination and splitting. Composite materials are expensive, and the price of T-1000 carbon fiber can reach up to 4000 yuan / kg by 2024. With the development of China's aviation industry, the proportion of composite materials used in China's aircraft products is gradually increasing. The invention of a specific tool can effectively reduce the scrap rate of composite materials during production and significantly reduce costs. SUMMARY

[0003] In order to solve the problem that the angle of the head and tail of the aircraft unequal-thickness composite part cannot be adjusted during assembly, causing the composite part to be unevenly stressed and delamination and splitting, an angle self-compensation method is invented to compensate for the structural included angle of the uneven thickness of the assembly interlayer. The core technology is to develop a special tool that automatically adjusts the installation angle of the bolt and nut axis in the connecting device during tightening by the design form of the body structure, directly compensates for the angle deviation of the bolt head and nut attachment surface, and thereby simultaneously ensures the attachment requirements of the bolt head and nut to the structure contact surface.

[0004] The technical scheme of the application is as follows:

[0005] The application discloses an angle self-compensation tool for assembling a non-uniform-thickness composite material part of an airplane, which is designed in a split mode, and the light rod section bolt guarantees effective shearing capacity of the tool, the inner thread is designed in an inner thread hole, the thread section bolt is designed in a stepped through hole in the inside and the stepped surface is an arc surface, the two are assembled by using an adjusting bolt, the length of the light rod is selected by measuring the thickness of the composite material part, and the requirement is that |L-H|<=1mm, that is, the length of the light rod cannot exceed the thickness of the sandwich by 1mm and the length of the light rod cannot be less than the thickness of the sandwich by 1mm.

[0006] The thread section bolt is matched with a self-locking nut and is tightened to guarantee reliable connection of the composite material part, the bolt head of the adjusting bolt is an arc surface and is matched with the stepped surface of the thread section bolt.

[0007] The angle self-compensation tool comprises a light rod inner thread bolt, an arc surface adjusting bolt, an inner twelve-angle compensation bolt, a groove cover, a sealing ring, an adjusting washer and a self-locking nut.

[0008] The light rod inner thread bolt has a countersunk head with an inner hexagonal groove and a light rod with a diameter d, and the tail end of the light rod has an MJ inner thread with a diameter d1; the groove at the countersunk head is used for wrenching the bolt, and the groove cover is used for covering after the connection is completed; wherein the selection of d should meet the hole diameter required by the drawing or other design data, d1 should be less than d, when d>=5mm, d1 is d / 2, when d>4mm<=d<5mm, d1 is d-1, and when d<4mm, d1 is d-1. The depth H' of the inner thread hole is H / 2+ / -0.1mm.

[0009] For example, the hole diameter on the drawing is 6.1mm or 6.2mm, and the diameter of the light rod should be 6.0mm, if the hole diameter on the drawing is 5.0mm, the diameter of the light rod is 5.0mm, d1 is 2.5mm, and when the thickness of the sandwich is 7.3mm, the depth of the inner thread hole is 3.6mm.

[0010] The arc surface adjusting bolt has an MJ outer thread with a diameter d1 and a length L1, is matched with the light rod inner thread bolt and has the same length of the threaded part, the bolt head has a circular arc surface with a radius R and a slot knife edge, a groove with a diameter d2 is designed below the bolt head, one aspect is to realize the function of the tool withdrawal groove during the bolt machining, and the other aspect is to adopt a clearance fit with the through hole of the inner twelve-angle compensation bolt, thereby increasing the rotation range of the connecting device and being suitable for a wider range of assembly sandwich angles.

[0011] The inner twelve-angle compensation bolt has an outer thread with a diameter d3 and an internal stepped through hole, the small end of the through hole is a circular hole with a diameter d4, the large end of the through hole is an inner twelve-angle hole with an inscribed circle diameter d5, the stepped surface of the through hole is designed as a circular arc surface with a radius R and is matched with the adjusting bolt to realize the self-adaptive adjusting function, and when the light rod inner thread bolt and the inner twelve-angle compensation bolt are combined through the bolt head of the adjusting bolt, hinge rotation is realized at the circular arc surface with the radius R.

[0012] d3 should be the same as the diameter of the polished rod, d5 is d3-2, d4 < d5.

[0013] The size of the groove diameter d2 should satisfy the formula: d4-d2≥A*sinθ*d5.

[0014] The length of the groove should be equal to the thickness of the washer p.

[0015] Where θ is the included angle of the interlayer, A is the coefficient of the formula, A=1.2 when the aperture D≤4.2mm, A=1.1 when the aperture 4.2mm≤D≤6.2mm, and A=1 when the aperture D≥6.2mm.

[0016] Where θ is the included angle of the interlayer, A is the coefficient of the formula, A=1.2 when the aperture D≤4.2mm, A=1.1 when the aperture 4.2mm≤D≤6.2mm, and A=1 when the aperture D≥6.2mm.

[0017] The radius of the circular arc surface R should satisfy: d4 < R≤d5, and R is preferably the same as d5.

[0018] Except d2, other sizes are integer times of 0.5mm, and d2 is integer times of 0.1mm.

[0019] For example, the aperture D=6.0mm on the drawing, the included angle θ is 15°, and the thickness of the washer p=2mm, then the outer thread diameter d3 of the inner twelve-angle compensation bolt should be 6mm, d1 is 3mm, d5 is 4mm, d4 is 3.5mm, and R is 4mm, then d2≤2.4mm is calculated, d2=2.3mm is taken, and the length of the groove is 2mm.

[0020] The sealing ring is installed at the bolt head and bolt rod part, to enhance the sealing function in the structural assembly, and replace the use of sealant.

[0021] The adjusting washer is installed at the nut and interlayer part, to ensure that the connecting device can meet the requirement of the protruding amount of the threaded polished rod when the thickness of the interlayer changes greatly, and increase the connection reliability; wherein the inner diameter d' of the washer should satisfy the relationship with the included angle θ of the interlayer: d'≥dsecθ, and the inner diameter should be the smallest under the requirement of other assembly, and the thickness p should satisfy p>dsinθcosθ, i.e. p>1 / 2*dsin2θ, and p should be as small as possible under the requirement of other requirements. For example, d=Ф6.2mm, and θ=20°, then d'>6.598mm is calculated, d' should be 7mm at this time, p>1.99 is calculated, and p should be 2mm at this time.

[0022] The self-locking nut adopts a conventional outer hexagonal head nut, the internal thread of which is matched with the MJ external thread d3 of the inner twelve-angle compensation bolt, realizing the assembly connection function and the self-locking function of the connecting device, and ensuring that the tool can be self-adaptively adjusted in the axial angle of the polished rod section and the threaded section during the tightening of the self-locking nut according to the interlayer angle of the composite material component, so as to ensure that the nut, the washer and the contact surface of the composite material component are well fitted. It is noted that the protruding amount of the bolt end after the nut is tightened should be not less than one pitch, that is, the bolt length h1 and the nut thickness and the pitch δ of the self-locking nut should satisfy h1-h2>δ. If the nut thickness h2 is 6 mm and the pitch δ is 1 mm, then h1>7 mm is calculated, and 8 mm should be taken at this time.

[0023] The auxiliary special tool is used to wrench the inner twelve-angle compensation bolt, and a replaceable tool bit with a twelve-angle bit head structure is adopted. The main structure comprises a tool bit bevel gear set, a stabilizing bearing, a shaft coupling, a DC motor with a speed reducer, an explosion-proof cable, a battery pack, a tool shell, a tool switch and a replaceable tool bit.

[0024] The tool is specifically assembled in the following manner: the power shaft on the tool bit bevel gear set is connected with the motor shaft of the DC motor with a speed reducer through the shaft coupling, the stabilizing bearing is arranged between the tool bit bevel gear set and the motor shaft at the middle section of the power shaft, the DC motor is connected with the battery pack and the tool switch through the explosion-proof cable, all the components except the switch are arranged inside the tool shell, the switch is arranged on the surface of the tool shell and fixed to the positions of all the components, and the replaceable tool bit is mechanically connected to the tool shell through the socket on the tool bit bevel gear set and the base on the tool bit bevel gear set.

[0025] The tool bit bevel gear set mainly comprises a pair of orthogonal bevel gears, a tool shaft with an inner four-square base and an orthogonal power shaft, realizes vertical transmission of power, saves tool use space and can work under difficult construction conditions.

[0026] The stabilizing bearing increases the stability of shaft rotation and is connected with the motor shaft of the DC motor with a speed reducer through the shaft coupling, realizing firm connection and stable output.

[0027] The DC motor with a speed reducer is connected with the battery pack and the tool switch through the explosion-proof cable, the tool switch adopts a button type, I / O reversal realizes the switch function, the motor is turned on and the tool starts to work when the I end is pressed, and the motor is turned off and the tool stops working when the O end is pressed.

[0028] The tool shell provides the positions for mounting and fixing all the tool components, all the components except the tool switch are arranged inside the tool shell, the tool switch is arranged in a special position on the surface of the tool shell, and when the tool works, the positions and spaces of all the components are ensured to be stable.

[0029] The replaceable tool bit has an outer dodecahedron tool bit and a square driving socket, the square driving socket is tightly matched on the inner square base of the tool shaft in the tool bit bevel gear set during use, the specification of the tool bit is matched with the hole size of the outer dodecahedron of the outer circle diameter d5, and different accessories are designed according to the hole specification of the inner dodecahedron compensation bolt.

[0030] The use method of the aircraft variable-thickness composite part assembly angle self-compensation tool is as follows:

[0031] First step: measure the sandwich thickness of the composite component at the place where the fastener is to be installed, and determine the parameters of the light rod internal thread bolt, the arc adjustable bolt and the inner dodecahedron compensation bolt according to the hole diameter of the drawing, the actual sandwich thickness and the size of the included angle.

[0032] Second step: take the light rod internal thread bolt, and pre-assemble the inner dodecahedron compensation bolt into a connecting device using the arc adjustable bolt, and manually tighten the arc adjustable bolt by using a slot screwdriver;

[0033] Third step: put the assembled connecting device into the sealing ring, and then pass through the fastener hole of the composite component, so that the light rod tail end of the light rod internal thread bolt is not lower than the surface of the component.

[0034] Fourth step: install the matched adjusting washer and self-locking nut, and tighten the inner dodecahedron compensation bolt by using a tool wrench, and turn the self-locking nut by using a special tool wrench, so that the composite component is clamped by gradually tightening;

[0035] Fifth step: check whether the inner dodecahedron compensation bolt is in complete contact with the surface of the composite component, and check the fitting gap; when it does not meet the requirements, loosen the self-locking nut 6 and repeat the operation of the fourth step to tighten again;

[0036] Sixth step: after checking, install the slot cover in the countersunk groove of the light rod internal thread bolt, and perform corrosion protection on the connecting device.

[0037] The beneficial effects of the present application are as follows:

[0038] (1) When the conventional bolt connection is used on the components with uneven assembly sandwich thickness, it is necessary to locally counterbore the components or use inclined washers, spherical washers and the like for compensation, which can damage the composite material structure and weaken the strength of the body, and increase the parallel inclined force on the surface of the component. The tool can adaptively adjust through the internal structure to ensure that only the clamping force of the nut is applied to the surface of the part, and the surface of the composite component is not damaged by counterboring.

[0039] (2) Conventional threaded connections using washer compensation have a limited application range, generally within 10°. This fixture can easily achieve adaptive angle adjustment within a maximum range of 30° by adjusting the parameters of each bolt through the adjustment of the arc surface, thus having a wider range of applications.

[0040] (3) Only the length of the smooth rod of the smooth rod internal thread bolt 1 needs to be adjusted to meet the connection of composite material components with different interlayer thicknesses. After summarizing the needs in the actual production process, the parameters of the required bolt assembly can be standardized. After standardization, the demand for manufacturing equipment can be greatly reduced while achieving large-scale production. Only the specific manufacturing module needs to be replaced to meet the demand, resulting in low manufacturing cost. Attached Figure Description

[0041] Figure 1 Structure 1 for the connecting device;

[0042] Figure 2 Structure two is the connecting device;

[0043] Figure 3 This is a schematic diagram of the working scenario when the angle is automatically compensated.

[0044] Figure 4 This is a diagram of a specialized tool.

[0045] In the diagram: 1. Internal threaded bolt for the smooth rod; 2. Adjustable arc bolt; 3. Internal dodecagonal compensating bolt; 4. Groove cover; 5. Sealing ring; 6. Adjusting washer; 7. Self-locking nut; 8. Cutter head bevel gear set; 9. Stabilizing bearing; 10. Coupling; 11. DC motor with gearbox; 12. Explosion-proof cable; 13. Battery pack; 14. Tool housing; 15. Tool switch; 16. Replaceable cutter head. Detailed Implementation

[0046] 1. Measure the interlayer thickness of the composite material component at the location where the fasteners are to be installed. Determine the parameters of the required smooth rod internal thread bolt 1, arc-shaped adjustable bolt 2, and internal twelve-angle compensating bolt 3 based on the hole diameter, actual interlayer thickness, and included angle in the drawings.

[0047] example:

[0048] The hole diameter at this location is 6.0mm on the drawing. The actual thickness of the composite material interlayer is 7.2mm after measurement. The included angle is 15° after measurement. Therefore, the diameter of the smooth rod of the smooth rod internal thread bolt 1 is 6mm, the length of the smooth rod part is 7mm, the diameter of the internal thread hole of the smooth rod bolt is 3mm, the internal thread pitch is 0.8mm, and the depth is 4mm.

[0049] The outer thread pitch of the arc adjustable bolt 2 matches the inner thread pitch of the polished rod inner thread bolt 1, which is selected as 0.8 mm, and the length of the threaded part matches the length of the inner threaded hole, which is selected as 4 mm. The self-locking nut is selected as HB8235MJ6x1 (according to the demand of electroplating). The thickness of the washer p>1 / 2*dsin2θ, the inner diameter of the washer d'>dsecθ, and it is calculated that p>1.5 mm and d'>6.21 mm, so p=2 mm and d'=7 mm are selected.

[0050] The outer thread pitch of the inner twelve-angle compensation bolt 3 matches the nut, which is 1 mm, and the length is selected as 8 mm. The outer thread diameter matches the hole diameter in the drawing, which is selected as 6 mm. The diameter d5 of the circle connecting the outer twelve-angle square hole of the through hole is 4 mm, the small diameter d4 of the through hole is 3.5 mm, and R is 4 mm. It is calculated that the groove diameter d2 of the arc adjustable bolt is less than or equal to 2.4 mm, so d2=2.3 mm is selected, and the groove length is 2 mm. Thus, the parameters of the three bolts and the type of the self-locking nut are determined.

[0051] 2. The polished rod inner thread bolt 1 is taken, and the inner twelve-angle compensation bolt 3 is pre-assembled into a connecting device using the arc adjustable bolt 2. A slot screwdriver is used to tighten the arc adjustable bolt 2 manually.

[0052] 3. The assembled connecting device is sleeved into the sealing ring 5, and then inserted into the fastener hole of the composite component. It should be ensured that the tail end of the polished rod inner thread bolt 1 is not lower than the surface of the component.

[0053] 4. The adjusting washer 6 and the self-locking nut 7 are installed, and the inner twelve-angle compensation bolt 3 is tightened using a tool wrench. The self-locking nut 7 is turned using a special tool wrench, and the composite component is gradually clamped by tightening.

[0054] 5. It is checked whether the inner twelve-angle compensation bolt 3 is in complete contact with the surface of the composite component, and the fit clearance is checked. When it does not meet the requirements, the self-locking nut 6 is loosened and the operation of 4 is repeated to tighten again.

[0055] 6. After the check is passed, the slot cover 4 is installed in the countersunk groove of the polished rod inner thread bolt 1, and the connecting device is protected against corrosion.

Claims

1. An angle self-compensating tooling for assembling an aircraft component made of composite material with variable thickness, characterized in that, It comprises an inner threaded bolt of a polished rod (1), an arc adjustable bolt (2), an inner twelve-angle compensation bolt (3), a groove cover (4), a sealing ring (5), an adjusting washer (6) and a self-locking nut (7); The inner threaded bolt of the polished rod (1) has a countersunk head with an inner hexagonal groove and a polished rod with a diameter d, and the tail end of the polished rod has an MJ inner thread with a diameter d1; the groove at the countersunk head is used for tightening the bolt, and the groove cover (4) is used for covering after the connection is completed; The arc adjustable bolt (2) has an MJ outer thread with a diameter d1 and a length L1, which is matched with the inner threaded bolt of the polished rod (1) and has the same length of the threaded part, and the bolt head has a circular arc surface with a radius R and a slot knife edge; a groove with a diameter d2 is designed below the bolt head; The inner twelve-angle compensation bolt (3) has an outer thread with a diameter d3 and an internal stepped through hole, the small end of the through hole is a circular hole with a diameter d4, the large end of the through hole is an inner twelve-angle hole with a circumscribed circle diameter d5, the stepped surface of the through hole is designed to have a circular arc surface with a radius R, and is matched with the arc adjustable bolt (2) to realize the self-adaptive adjustment function; when the inner threaded bolt of the polished rod (1) and the inner twelve-angle compensation bolt (3) are combined through the bolt head of the arc adjustable bolt (2), hinge rotation is realized at the circular arc surface with a radius R; The sealing ring (5) is installed at the bolt head and the bolt rod part to enhance the sealing function in the structure assembly and replace the use of sealant; The adjusting washer (6) is installed at the nut and the interlayer part to ensure that the connecting device can meet the requirement of the protruding amount of the threaded polished rod when the thickness of the interlayer changes greatly, and increase the connection reliability; wherein the inner diameter d' of the washer should meet the relationship with the interlayer angle θ: d' ≥ dsecθ, and the inner diameter should be the smallest under the requirement of other assembly, and the thickness p should meet p > dsinθcosθ, that is, p > 1 / 2·dsin2θ; The self-locking nut (7) adopts a conventional outer hexagonal head nut, and the inner thread thereof is matched with the MJ outer thread d3 of the inner twelve-angle compensation bolt (3).

2. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts according to claim 1, characterized in that, The size of d3 should be the same as the diameter d of the polished rod, d5 is d3-2, and d4 < d5; the size of the diameter of the groove d2 should meet the formula: d4-d2 ≥ A·sinθ·d5.

3. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts according to claim 1 or 2, characterized in that, The length of the groove should be equal to the thickness p of the washer.

4. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts according to claim 1 or 2, characterized in that, It also comprises auxiliary special tools, including a cutter head bevel gear set (8), a stable bearing (9), a shaft coupling (10), a direct current motor with a reduction box (11), an explosion-proof cable (12), a battery pack (13), a tool shell (14), a tool switch (15) and a replaceable cutter head (16). The power shaft of the bevel gear set (8) is connected with the motor shaft of the direct current motor (11) with a speed reducer through a coupling (10), a stabilizing bearing (9) is arranged between the bevel gear set (8) and the motor shaft at the middle section of the power shaft, the direct current motor is connected with the battery pack (13) and the tool switch (15) through an explosion-proof cable (12), all the components are arranged in the tool shell (14) except the switch, the switch is arranged on the surface of the tool shell and fixes the positions of all the components, the replaceable tool bit (16) is mechanically connected with the base of the bevel gear set (8) on the tool body through the socket.

5. The angle self-compensating tooling for assembling aircraft out-of- thickness composite parts of claim 4, wherein, The bevel gear set (8) is composed of a pair of orthogonal bevel gears, a tool shaft with an inner square base and an orthogonal power shaft.

6. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts of claim 4, wherein, The stabilizing bearing (9) increases the stability of the shaft rotation and is connected with the motor shaft of the direct current motor (11) with a speed reducer through a coupling (10), so that the connection is firm and the output is stable.

7. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts of claim 4, wherein, The direct current motor (11) is connected with the battery pack (13) and the tool switch (15) through an explosion-proof cable (12), the tool switch (15) adopts a button mode, the I / O reversing realizes the switch function, when the I end is pressed, the motor is started and the tool starts to work, when the O end is pressed, the motor is stopped and the tool stops working.

8. The angle self-compensating tooling for assembling aircraft out-of- autoclave composite parts of claim 4, wherein, The replaceable tool bit (16) has an outer dodecagon tool bit and a square driving socket, when used, the square driving socket is tightly matched on the inner square base of the tool shaft in the bevel gear set (8), the size of the tool bit matches the size of the through hole of the outer dodecagon with the outer connecting circle diameter d5.

9. The use of the assembly angle self-compensating tooling for aircraft composite parts of variable thickness, according to claim 1, characterized in that, The steps are as follows: First step: measure the thickness of the sandwich of the composite material member where the fastener is to be installed; Second step: take the light rod internal thread bolt (1) and use the arc adjustable bolt (2) to pre-assemble the inner dodecagon compensation bolt (3) into a connecting device, use a slot screwdriver to tighten the arc adjustable bolt (2) manually; Third step: put the assembled connecting device into the sealing ring (5), then pass through the fastener hole of the composite material member, and ensure that the tail end of the light rod internal thread bolt (1) is not lower than the surface of the member; Fourth step: install the matched adjusting washer (6) and self-locking nut (7), and use a tool to tighten the inner dodecagon compensation bolt (3), use a special tool to tighten the self-locking nut (7), and gradually tighten to clamp the composite material member; Fifth step: check whether the inner dodecagon compensation bolt (3) is in complete contact with the surface of the composite material member, and check the fit clearance; when it does not meet the requirements, loosen the self-locking nut (7) and repeat the fourth step to tighten again; Sixth step: after checking, install the slot cover (4) in the countersunk slot of the light rod internal thread bolt (1), and protect the connecting device from corrosion.

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