JP2013095423A - Lightning-resistant fastener and cap for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightning-resistant fastener capable of reliably encapsulating an arc between a cap and a member such as a wing panel, even when the cap is lifted, and a cap for the lightning-resistant fastener.SOLUTION: The cap 30C has its inside provided with a step part (butt part) 50 which butts against a collar 26 fastened to a fastener member 24. A clearance 51 is formed between one end 30a of the cap 30C and a member 22 while making the step part 50 butt against the collar 26. When a sealant material 34 infilled into the cap 30C overflows from an opening at the one end 30a of the cap 30C, it extends to an outer peripheral side from the clearance 51. This can prevent the cap 30C from being pushed back in the direction of isolation from the member 22, by suppressing an increase in the pressure of the sealant material 34 in the cap 30C.

Description

  The present invention relates to a lightning-resistant fastener used for an aircraft body, particularly a wing, and a cap for a lightning-resistant fastener.

A wing constituting an aircraft body generally has a hollow structure, and a wing panel forming a wing surface is fixed to a structural member inside the wing by a fastener member (fastener).
At this time, the fastener member inserts the pin-shaped fastener body into the through-hole formed in both the wing panel and the structural member inside the wing from the outside of the wing, and the tip of the fastener member is fastened from the inside of the wing. By fixing with wing panel, the wing panel and the structural member are fastened.
In addition, structural members other than the wing panel and members for fixing the equipment are also fastened and fixed by fastener members inside the wing and the body.
At this time, the fastener member is inserted such that the pin-shaped fastener body passes through both of the through holes formed in both of the members to be fixed to each other, and the tip portion thereof is fixed with a fastening member (collar). And fasten both members together.
The number of wing panels or members to be fixed is not limited to two.

  By the way, in an aircraft, it is necessary to take all possible measures against lightning for explosion protection. When lightning occurs in an aircraft and a large current flows through a wing panel such as a main wing or a structural member, a part or all of the current flows in a fastening portion formed by the fastener body and the fastening member. When the current value exceeds the limit value of the allowable passage current at each fastening portion, a discharge called an electric arc (or thermal spark) is generated (hereinafter referred to as an arc in this specification). This is because the current passing through the fastening portion causes a sudden temperature rise at the fastening interface of the member mainly composed of the conductive member constituting the fastening portion, the member is locally melted, and discharge is generated in the nearby atmosphere. In many cases, the molten material, called hot particles, is scattered from the melted portion. Generally, the inner space of the wing also serves as a fuel tank, so it is necessary to take measures against explosions. Therefore, during lightning strikes, by preventing arc generation or sealing the arc, it is possible to prevent discharge of the generated arc and prevent hot particles scattered from it from coming into contact with combustible fuel vapor. It is necessary to prevent ignition. Here, the part where the flammable fuel vapor may exist is a surge tank (such as a vent scoop or a burst disk) installed in the fuel tank, generally on the wing tip side of the fuel tank, inside the wing and the fuselage. Inside the tank) and inside the fuel system equipment.

  Therefore, as shown in FIG. 5, a cap 3 made of an insulating material is attached so as to cover the front end portion 1 a of the fastener member 1 and the fastening fitting 2 fastened to the fastener member 1, and further, a sealant is provided inside the cap 3. The structure which fills the agent 4 and closes the clearance gap between the front-end | tip part 1a of the fastener member 1, and the fastener 2 and the cap 3 is proposed (for example, refer patent document 1).

  In the fastening work site using the fastener member 1, as shown in FIG. 5A, when the cap 3 is attached to the tip end portion 1 a of the fastener member 1 and the fastener 2, the sealant 4 is placed in the inner space of the cap 3. Is filled in advance. Then, as shown in FIG. 5 (b), the cap 3 filled with the sealant agent 4 is put on the front end portion 1 a of the fastener member 1 and the fastener 2. Then, excess sealant 4 in the cap 3 overflows from the opening of the cap 3. As shown in FIG. 5C, in the state where the end surface 3a on the opening side of the cap 3 is pressed against the surface of the member 5 such as the wing panel, the overflowing sealant 4 is separated from the cap 3 and the member 5 such as the wing panel. Between the cap 3 and the outer peripheral side of the cap 3 in an annularly raised state so that the arc can be reliably contained at the interface between the cap 3 and the member 5 such as a wing panel.

JP 2010-254287 A

The sealant agent 4 as described above has a high viscosity. For this reason, when the gap between the end surface 3a on the opening side of the cap 3 and the member 5 such as the wing panel is reduced at the final stage of mounting the cap 3, the sealant agent 4 is less likely to flow out of the cap 3 from this portion. And the pressure of the sealant 4 sandwiched between the wing panel and other members 5 increases.
Further, since the sealant agent 4 has elasticity as well as viscosity, as shown in FIG. 5D, even if the cap 3 is pressed against the member 5 such as a wing panel, it is pressed by the pressure and elasticity described above. There is a problem that the cap 3 is pushed back in the direction away from the member 5.

When the cap 3 is pushed back and the end surface 3a on the opening side of the cap 3 is separated from the member 5 such as a wing panel, a gap 7 is generated here, and the arc cannot be contained.
Further, the cap 3 may be lifted, and the sealant agent 4 interposed between the end face of the cap 3 and the member 5 such as a wing panel may become thin in the radial direction of the cap 3. Also in this case, there is a possibility that the arc cannot be reliably contained at the interface between the cap 3 and the member 5 such as the wing panel, which is not preferable.

Further, as shown in FIG. 5 (e), the sealant agent 4 </ b> S existing in a ring shape on the member 5 such as the wing panel on the outer peripheral side of the cap 3 is the sealant agent 4 in the cap 3 or the cap 3. Since the connection with is thin, there is a possibility of peeling off from here after curing. Therefore, after the cap 3 is mounted, it is conceivable that the operator seals the sealant 4 on the outer peripheral side toward the cap 3 side with a finger or a spatula, etc., so that it takes time and effort. The quality depends on the skill level of the operator.
The present invention has been made on the basis of such a technical problem. Even when the cap is lifted, the lightning-resistant fastener capable of reliably containing an arc between the cap and a member such as a wing panel. The aim is to provide a cap for lightning-resistant fasteners.

The lightning-resistant fastener of the present invention based on such an object penetrates the first member and the second member in order to fasten the second member to the first member constituting the aircraft fuselage. A fastener member having a shaft portion protruding on at least one side of the one member and the second member, and a shaft portion of the fastener member protruding on at least one side of the first member and the second member A cap made of an insulating material to be attached, and a sealant made of an insulating material filled in the cap to close a space between the cap and the fastener member. The cap is attached to the fastener member or the fastener member. The cap has a butting portion that abuts the fastening member to be fastened, and the abutting portion is abutted against the fastener member or the fastening member fastened to the fastener member. Surface of the first member, or clearance is formed between the cap and the second member, the sealant in the clearance may be a lightning protection fastener, characterized in that it is filled.
A clearance is formed between the cap and the second member in a state where the abutting portion is abutted against the fastener member or the fastening member fastened to the fastener member, so that the cap filled with the sealant is removed from the fastener member. When covering the end portion, the sealant overflows from the clearance to the outer peripheral side, so that an increase in the pressure of the sealant can be suppressed.
Further, when the clearance is filled with the sealant agent, even if the cap moves away from the first member or the second member, the sealant agent follows the cap, so the cap and the first member or the first member An arc containment function between the surfaces of the two members can be reliably exhibited.

When the shaft portion of the fastener member protrudes on both sides of the first member and the second member, the cap can be provided on each of one end side and the other end side of the shaft portion. That is, in this case, two caps are used.

The present invention also provides a cap that is attached so as to cover the front end of the fastener member that fastens the first member and the second member. The cap is made of an insulating material and has an opening for receiving the tip of the fastener member. And this cap is used in the state which filled the opening with the sealant agent which consists of an insulating material while it has the contact part which contact | abuts the fastener member fastened to a fastener member or a fastener member inside a cap. It is characterized by being.

When the cap is attached in a state where the abutting portion is abutted against the fastener member or the fastening member fastened to the fastener member, the clearance between the cap and the surface of the first member or between the cap and the second member Is formed, and the sealant is filled in the clearance.

  According to the present invention, even when the cap is lifted, it is possible to reliably contain the arc between the cap and the first member or the second member such as the wing panel.

It is sectional drawing which shows the structure of the lightning-resistant fastener and cap in 1st embodiment. It is sectional drawing which shows a state when a cap floats. It is sectional drawing which shows the structure of the lightning-resistant fastener and cap in 2nd embodiment. It is sectional drawing which shows the structure of the lightning-resistant fastener and cap in 3rd embodiment. It is sectional drawing which shows the conventional lightning-resistant fastener.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
[First embodiment]
FIG. 1 is a cross-sectional view of a part of a wing constituting a fuselage of an aircraft to which a lightning-resistant fastener and a lightning-resistant fastener cap according to the present embodiment are applied.
As shown in FIG. 1A, the wing 20 has a wing panel whose outer shell is made of a metal material such as CFRP (Carbon Fiber Reinforced Plastics), which is a composite material of carbon fiber and resin, or an aluminum alloy. (First member) 21 is formed. A reinforcing structural material, a fuel tank, and various devices provided inside the wing 20 are connected to a wing panel 21 via a member (second member) 22 such as a stay formed of a metal material such as an aluminum alloy. It is fixed to. A member 22 such as a stay is attached to the wing panel 21 by a fastener member 24.

The fastener member 24 includes a pin-shaped fastener main body 25 and a collar 26 attached to the fastener main body 25 on the inner side of the wing 20.
The fastener body 25 and the collar 26 are generally formed of a metal material in terms of strength. The fastener body 25 having a pin shape has a thread groove (threaded portion) 25a formed at the tip, and the rear end is a diameter-expanded portion 25b having a diameter increased from the tip. The fastener body 25 is inserted from the outside of the wing 20 into holes 21 a and 22 a formed through the wing panel 21 and the member 22, and the enlarged diameter portion 25 b at the rear end is abutted against the outer surface of the wing panel 21. In this state, the tip is projected inward of the wing 20.
The collar 26 has a cylindrical shape, and a thread groove that meshes with the thread groove 25a of the fastener body 25 is formed on the inner peripheral surface thereof. The collar 26 is screwed into a thread groove 25 a of the fastener body 25 protruding inward of the wing 20. As a result, the wing panel 21 and the member 22 are sandwiched between the enlarged diameter portion 25 b of the fastener body 25 and the collar 26, and the member 22 is fixed to the wing panel 21.

Now, on the inner space side of the blade 20, a cap 30 </ b> A is attached to the fastener member 24, and the cap 30 </ b> A is filled with an insulating sealant 34.
As shown in FIG. 1 (b), the cap 30A has a circular cross section, and has an umbrella shape in which only the one end 30a side is open and the inner and outer diameters gradually decrease toward the other end 30b. ing. The cap 30A can be formed in advance using the same kind of material as the sealant agent 34. In addition to this, the cap 30A can also be formed of an insulating resin such as PPS (polyphenylene sulfide resin), polyimide, PEEK (polyether-ether-ketone resin), or nylon resin.

The cap 30A is formed with a tapered surface 30c whose outer diameter gradually decreases from the other end 30b side toward the one end 30a at the outer peripheral edge of the one end 30a. As shown in FIG. 1A, the tapered surface 30c may be formed so that the crossing angle θ with respect to the surface 22f of the member 22 is about 30 to 60 °, and the cross section of the cap 30A along the axis thereof. The taper surface 30c may be linear, or may have a shape that is recessed inward or a shape that bulges outward.
Further, the one end 30a of the cap 30A is formed with a flat surface 30d orthogonal to the axis of the cap 30A, and a tapered surface 30c is formed on the outer peripheral side of the flat surface 30d.
Here, when the thickness of the cap 30A is, for example, 2.5 mm, the height h of the tapered surface 30c is preferably about 1 to 2.5 mm. The width w of the flat surface 30d is preferably about 0.5 to 1.5 mm.

  In such a cap 30A, the inner diameter of the inner peripheral surface is set so that a predetermined gap is formed between the fastener body 25 and the collar 26 when the cap 30A is attached to the fastener member 24. Yes. In particular, at the one end 30a on the opening side of the cap 30A, the cap 30A is formed so as to ensure a gap of a predetermined dimension t or more between the inner peripheral surface of the cap 30A and the fastener body 25.

  In a state where the cap 30A is attached to the fastener member 24, the sealant agent 34 having an insulating property is filled in the cap 30A. The sealant 34 is interposed between the inner peripheral surface of the cap 30A and the fastener body 25 and the collar 26, so that the insulation between the cap 30A and the fastener member 24 is further enhanced. And in the one end part 30a which is the opening side of the cap 30A, since the sealant agent 34 between the inner peripheral surface of the cap 30A and the fastener body 25 has a thickness of a predetermined dimension t or more, the cap 30A Insulation performance between the inner peripheral surface of the steel plate and the fastener body 25 is ensured.

When the cap 30A is attached to the fastener member 24 that fastens the wing panel 21 and the member 22, an uncured sealant 34 is filled in the cap 30A. Then, in the internal space of the blade 20, the cap 30 </ b> A is pressed against the fastener body 25 of each fastener member 24 protruding inward.
At this time, the sealant agent 34 filled in the cap 30A has a filling amount that overflows from the opening of the one end 30a of the cap 30A. When the one end 30a of the cap 30A hits the surface 22f of the member 22, the overflowing sealant 34 is between the flat surface 30d of the one end 30a of the cap 30A and the surface 22f of the member 22, and the tapered surface 30c and the member. 22 (hereinafter, the sealant agent 34 interposed between the tapered surface 30c and the surface 22f of the member 22 may be referred to as a sealant agent 34B). Here, the sealant agent 34 is filled between the tapered surface 30c and the surface 22f of the member 22, and a sufficient amount is interposed. Further, the sealant agent 34 spreads annularly on the outer peripheral side of the one end portion 30a of the cap 30A, and rises to a position higher than the tapered surface 30c on the surface 22f of the member 22 (hereinafter, this sealant agent 34 is referred to as a sealant agent 34S). Sometimes called).

  Further, when the filled sealant 34 is cured, a lightning-resistant fastener including the fastener member 24 to which the cap 30A is attached is configured.

According to the above-described configuration, the tapered surface 30c whose outer diameter gradually decreases from the other end 30b side toward the one end 30a is formed on the one end 30a of the cap 30A. The sealant 34B overflowing from the cap 30A is interposed between the tapered surface 30c and the surface 22f of the member 22.
Accordingly, as shown in FIG. 2A, the cap 30A is separated from the member 22 by the pressure and elasticity of the sealant 34 sandwiched between the cap 30A and the member 22 at the final stage where the cap 30A is mounted. Even when the sealant 34B is pushed back in the direction to be pressed, the sealant 34B interposed between the tapered surface 30c and the surface 22f of the member 22 has a sufficient thickness. Therefore, even if the one end 30a of the cap 30A and the surface 22f of the member 22 are separated from each other, the sealant agent 34B is not easily interrupted, and the sealant agent 34S swelled in an annular shape on the outer peripheral side can be sucked. It becomes even more difficult to break.
Therefore, even when the cap 30A is lifted, the arc can be reliably contained between the cap 30A and the surface of the member 22, and a lightning-resistant fastener having high reliability can be configured.

  Further, as shown in FIG. 2B, an annular sealant 34S on the outer peripheral side is integrated with the sealant 34B interposed between the taper surface 30c and the surface 22f of the member 22, so that the annular It is possible to prevent the sealant agent 34S from falling off. Therefore, it is not necessary to mold the sealant agent 34S overflowing to the outer peripheral side of the cap 30, and the operation can be performed easily and reliably.

[Second Embodiment]
Next, a second embodiment of the lightning-resistant fastener and the cap of the lightning-resistant fastener according to the present invention will be described. In the following description, the description will focus on components that are different from those of the first embodiment, and components that are the same as those described in the first embodiment will be denoted by the same reference numerals in the drawings. Is omitted.
As shown in FIGS. 3A and 3B, the cap 30B of the present embodiment is formed of the same material and substantially the same shape as the cap 30A of the first embodiment, but at the other end 30b, A through hole 40 is formed.

In the cap 30 </ b> B having such a through hole 40, the cap 30 </ b> B pre-filled with the sealant 34 is attached to the fastener member 24 that fastens the wing panel 21 and the member 22 in the same manner as in the first embodiment. The cap 30 </ b> B is disposed so as to cover the front end of the fastener body 25 of each fastener member 24.
At this time, the sealant agent 34 filled in the cap 30B overflows from the opening of the one end 30a of the cap 30B and also overflows from the through hole 40.
Thereby, it can suppress that the pressure of the sealant agent 34 in the cap 30B increases, and can prevent the cap 30B from being pushed back in the direction away from the member 22. Further, when the cap 30B is pushed back, the sealant agent 34 filled in the cap 30B overflows from the opening of the one end 30a of the cap 30B, as in the first embodiment. The overflowing sealant agent 34 is interposed between the flat surface 30d of the one end 30a of the cap 30B and the surface 22f of the member 22, and between the tapered surface 30c and the surface 22f of the member 22, respectively. Further, the sealant 34 spreads annularly on the outer peripheral side of the one end portion 30a of the cap 30B, and rises to a position higher than the tapered surface 30c on the surface 22f of the member 22. As a result, similarly to the first embodiment, even when the cap 30B is lifted, the arc can be reliably contained between the cap 30B and the surface of the member 22, and high reliability is obtained. A lightning-resistant fastener can be constructed.

  Here, the through hole 40 may have a constant diameter from the inner side to the outer side of the cap 30B, or the inner side, the outer side, or an intermediate part thereof may be formed so that the inner diameter becomes smaller. .

[Third embodiment]
Next, a third embodiment of the lightning-resistant fastener and the cap of the lightning-resistant fastener according to the present invention will be described. In the following description, the description will focus on components that are different from those of the first embodiment, and components that are the same as those described in the first embodiment will be denoted by the same reference numerals in the drawings. Is omitted.
As shown in FIG. 4, the cap 30 </ b> C of the present embodiment is formed with a stepped portion (butting portion) 50 that abuts against the collar 26 fastened to the fastener member 24. The size of the step portion 50 is set so that a clearance 51 is formed between the one end portion 30a of the cap 30C and the surface 22f of the member 22 in a state where the step portion 50 abuts against the collar 26.

According to such a configuration, in the same manner as in the first embodiment, each fastener member is attached to the fastener member 24 that fastens the wing panel 21 and the member 22 with the cap 30C pre-filled with the sealant 34. Press against 24 fastener bodies 25.
At this time, when the step portion 50 of the cap 30C abuts against the collar 26, the pushing amount of the cap 30C is regulated. A clearance 51 is formed between the end portion 30 a of the cap 30 </ b> C and the member 22 in a state where the stepped portion 50 abuts against the collar 26. Therefore, when the sealant 34 filled in the cap 30C overflows from the opening of the one end 30a of the cap 30C as the cap 30C is pushed in, the clearance between the one end 30a of the cap 30C and the member 22 is increased. It spreads from 51 to the outer peripheral side.
Thereby, it can suppress that the pressure of the sealant agent 34 in the cap 30C increases, and can prevent the cap 30C from being pushed back in the direction away from the member 22. Further, since the clearance 51 is formed between the one end 30a of the cap 30C and the member 22, and the sealant agent 34 is filled therein, the cap 30C and the member 22 can be connected even when the cap 30C is pushed back. The arc can be surely confined at the interface, and a lightning-resistant fastener having high reliability can be configured.

In the above embodiment, the wing panel 21 and the member 22 are fastened by the fastener member 24. However, the fastener member 24 and the caps 30A, 30B, and 30C may be applied to any other part. good. Further, the fastener main body 25 of the fastener member 24 can be protruded from both sides of the two members, and caps 30A, 30B, 30C can be provided on both sides thereof.
Further, the outer shape of the caps 30A, 30B, and 30C may be any shape.
Further, in the first and second embodiments, the tapered surface 30c is formed to be continuous in the circumferential direction, but a plurality of tapered surfaces 30c may be intermittently formed in the circumferential direction. .
In addition, a cap having a tapered surface such as the caps 30 </ b> A to 30 </ b> C of the above-described embodiment is also provided on the outer surface side of the wing 20 so as to cover the enlarged diameter portion 25 b of the fastener main body 25 constituting the fastener member 24. The sealant agent may be filled between the cap and the enlarged diameter portion 25b, and this sealant agent may be filled between the taper surface of the cap portion and the outer surface of the blade 20.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

20 wing 21 wing panel (first member)
21a hole 22 member (second member)
22a Surface 24 Fastener member 25 Fastener body 26 Collar 30A, 30B, 30C Cap 30a One end 30b Other end 30c Tapered surface 30d Flat surface 34 Sealant agent 40 Through hole 50 Step portion (butting portion)
51 clearance

Claims (4)

In order to fasten the second member to the first member constituting the aircraft body, the first member and the second member are penetrated, and at least one of the first member and the second member A fastener member having a shaft portion protruding on the side of
A cap made of an insulating material attached so as to cover the shaft portion of the fastener member protruding to at least one side of the first member and the second member;
A sealant made of an insulating material that fills the inside of the cap and closes a space between the cap and the fastener member;
The cap has an abutting portion that abuts against the fastener member or a fastening member fastened to the fastener member,
Clearance between the cap and the surface of the first member or between the cap and the second member in a state where the abutting portion is abutted against the fastener member or a fastening member fastened to the fastener member And the clearance is filled with the sealant agent. The shaft portion of the fastener member protrudes on both sides of the first member and the second member;
The lightning-resistant fastener according to claim 1, wherein the cap is provided on each of one end side and the other end side of the shaft portion. A cap attached to cover the tip of a fastener member that fastens the first member and the second member,
The cap is made of an insulating material and has an opening for receiving the tip of the fastener member;
The cap has an abutting portion that abuts against the fastener member or a fastening member fastened to the fastener member inside the cap,
A cap for a lightning-resistant fastener, wherein the cap is used in a state where a sealant made of an insulating material is filled in the opening.   When the cap is attached in a state where the abutting portion is abutted against the fastener member or a fastening member fastened to the fastener member, the cap and the surface of the first member, or the cap and the second The lightning fastener fastener cap according to claim 3, wherein a clearance is formed between the member and the sealant agent is filled in the clearance.

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