JP2009138780A - Fastener structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fastener structure capable of properly removing a shape memory alloy washer in disassembling, without expanding the shape memory alloy washer, when fastening a fastening part to an installation part, by using a screw member used by combining a screw, the shape memory alloy washer and a ring body. <P>SOLUTION: This fastener structure 1 is provided for fastening the fastening part 10 to the installation part 20 by using the screw member 4 composed of the screw 2 having a screw head part 2a on one end side of a male screw part 2d, the shape memory alloy washer 3 and the ring body 6. The ring body 6 has a screw abutting surface 6a sand a washer abutting surface 6b. The washer abutting surface 6b comprises an inclined face inclining in the approaching direction to the screw abutting surface toward the ring peripheral edge in the diametrical direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is applied to the manufacture of products that can be easily disassembled such that air conditioners, washing machines, refrigerators, televisions, battery packs, simple chargers, etc., and their components or accessory parts, or used materials can be reused, The present invention relates to a structure of a fastening body using a shape memory alloy washer and screws effective for dismantling the product.

  In general, when dismantling a screwed product, conventionally, the operation of loosening the screw and removing the screw has been performed manually. Recently, technology development to achieve so-called easy disassembly using a shape memory alloy washer in combination with a screw at the time of fastening has progressed, and this method is also attracting attention from the viewpoint of recycling use of parts and resource recovery Yes.

  Such an easy disassembly technique is described in Patent Document 1, for example. First, when manufacturing a screw fastening body, a composite product in which a shape memory alloy washer is inserted into a screw and combined is first prepared. The shape memory alloy washer is preliminarily memorized so as to have an inner diameter larger than the outer diameter of the screw head at a predetermined temperature or more, and has a small inner diameter that can be inserted into the screw shaft when fastening the parts. The processing is adjusted. Therefore, when a product is manufactured by fastening parts using the composite product, when disassembling the product after use, if the washer is heated to a predetermined temperature or more, the large diameter stored in the washer inner diameter is stored. Since the shape memory alloy washer pops out from the head of the screw, the product can be disassembled within a short time.

On the other hand, usually, when screwing, a large fastening force (torque) is applied to the screw so that the parts can be securely fastened. At that time, if the washer is used in combination with a screw, and the head shaft side of the screw is machined into a countersunk screw shape, the washer will easily come out of the screw head when the product is disassembled. . Thus, the screw having the screw head having a countersunk screw shape is convenient when the washer is removed.
JP 2005-16713 A

However, the conventional screw has the following problems when it is used in combination with a washer made of shape memory alloy in consideration of dismantling.
In other words, when a conventional screw is screwed directly into a female screw part or an installation surface for the purpose of fastening a fastening part, the head part of the screw Is rotated and screwed into the washer inner diameter. Then, when the screw is rotated and screwed in, the washer arm portion expands in a direction in which the inner diameter of the washer is larger than the outer diameter of the head of the screw, and it becomes difficult to achieve the fastening purpose. .

  The present invention has been devised in view of the above-described problems, and uses a screw member that is a combination of a screw, a shape memory alloy washer, and a ring body to fasten a fastening component to an installation portion. Furthermore, it is an object of the present invention to provide a fastening structure that makes it difficult for the arms of the shape memory alloy washer to expand even when a necessary fastening force is applied, and that the shape memory alloy washer can be easily removed when dismantling. To do.

  That is, the fastening body structure according to the present invention is a shape formed in a shape in which an annular part is cut off by a shape memory alloy with a screw having a head on one end side of the male screw portion and a dimension corresponding to the screw. An installation portion using a screw member comprising a memory alloy washer, and an annular ring body that is inserted and disposed between the shape memory alloy washer and the head of the screw. The shape memory alloy washer is formed so that the inner diameter is larger than the outer diameter of the head above the shape restoration temperature of the material. The fastening component has a screw hole, and the screw hole has a diameter larger than that of the screw head and the ring body, and smaller than a washer outer diameter of the shape memory alloy washer. The ring body is One surface has a washer contact surface that contacts the washer made of shape memory alloy, and the other surface has a screw contact surface that contacts the lower surface of the head of the screw, and the washer contact surface is In the diametrical direction, an inclined surface that is inclined in a direction approaching the screw contact surface as it goes toward the ring periphery is provided.

  In the fastening body structure configured as described above, when the screw is tightened, the head portion of the screw and the ring body are idle, and the screw is advanced without rotating the ring body to press the shape memory alloy washer. Therefore, the screw presses the ring body toward the installation surface and rotates the shape memory alloy washer to the fastening part without rotating the ring body with respect to the inclined surface of the ring body or the ring contact surface of the shape memory alloy washer. Fastening can be performed in a state where a torque exceeding a predetermined level is generated. And when disassembling the fastening body structure, the washer contact surface of the ring body is an inclined surface, so when the washer made of shape memory alloy is heated to a predetermined temperature or higher, the head of the screw is expanded when the washer arm portion expands. It is in a state where it is easy to leave. Therefore, in the fastening body structure, the shape memory alloy washer is smoothly removed from the head portion of the screw, and the fastening component can be removed from the installation portion without removing the screw.

  Moreover, the said fastening body structure WHEREIN: The said ring body is good also as a structure provided with the inclined surface which inclines in the direction approaching the said washer contact surface, as the said screw contact surface goes to a ring periphery in a diameter direction.

  When the screw is screwed in with a screwdriver or the like, the fastening body structure configured as described above has an inclined surface on the screw contact surface of the ring body that comes into contact with the head of the screw. The abutting contact portion becomes smaller, and the screw head and the ring body easily rotate freely, and the force applied from the screw head is concentrated and transmitted from the ring body to the shape memory alloy washer side and pressed. . Further, when the fastening body structure is disassembled, the contact area between the ring body and the screw head is small, so that the screw and the ring body can be easily separated.

  Further, in the fastening body structure, the ring body includes a ring portion having the washer contact surface and the screw contact surface, and a step portion formed in a cylindrical shape continuously on the washer contact surface side of the ring portion. The step portion is formed to have a smaller diameter than the ring portion (and the head portion of the screw) and a diameter larger than the diameter of the male screw portion.

  In the fastening body structure configured in this way, when the screw is turned, the screw contact surface formed on the ring portion of the ring body slides with respect to the head of the screw, causing the screw and the ring body to idle, This step facilitates positioning of the shape memory alloy washer.

  Further, in the fastening body structure, the screw includes a columnar screw step portion having a diameter smaller than the head portion and larger in diameter than the male screw portion between the head portion and the male screw portion, The ring body includes the screw contact surface and a washer contact surface that contacts the shape memory alloy washer, and further includes an insertion hole that can be inserted into a screw step portion of the screw, the screw step portion being the ring body. Further, the length may be equal to or greater than the total thickness of the shape memory alloy washers.

  In the fastening body structure configured in this way, when the screw is turned, the screw contact surface of the ring body slides with respect to the head portion of the screw, and the screw and the ring body rotate freely. Contributes to positioning the shape memory alloy washer so that it is in the center with respect to the shaft portion of the screw.

  Furthermore, in the said fastening body structure, an uneven | corrugated | grooved part is provided in one of the washer contact surface of the said ring body, or the ring contact surface of the said shape memory alloy washer, and the said uneven | corrugated | grooved part is from the inner diameter side of the said ring body. The convex portion and the concave portion are formed toward the outer diameter side or from the inner diameter side to the outer diameter side of the shape memory alloy washer.

  The fastening body structure configured in this way is engaged so that the concave and convex portions formed on the ring body or the shape memory alloy washer rotate around the ring body and the shape memory alloy washer when the screw is tightened. To do. Therefore, even if the ring body rotates without spinning when the screw is turned, the uneven part is caught and the shape memory alloy washer and the ring body are rotated, and the washer arm of the shape memory alloy washer is Suppresses spreading.

  In the fastening body structure according to the present invention, since the screw presses the shape memory alloy washer through the ring body, the contact surface between the screw head and the ring body slips, and the rotation of the screw is transmitted to the ring. The fastening part is fastened to the installation surface with a washer made of shape memory alloy without rotating without rotating the ring body. For this reason, the fastening body structure uses a shape memory alloy washer considering the time of disassembly, and even if a sufficient torque is applied by a driver or the like, the washer arm portion of the shape memory alloy washer can be expanded. In addition, the fastening part can be tightened toward the installation part, and the arm part of the shape memory alloy washer can be widened only by heating at the time of disassembly to facilitate removal of the fastening part. Therefore, it is convenient for facilitating the dismantling work of the product and recycling parts or collecting resources.

  The fastening body structure is provided with an inclination on the screw contact surface of the ring body, so that the contact area between the screw and the ring body is reduced, the sliding between the screw and the ring body is improved, and the screw and the ring body are idle. It becomes easy. Therefore, the shape memory alloy washer can be efficiently pressed to further suppress the expansion of the washer arm portion of the shape memory alloy washer at the time of fastening.

  In the fastening body structure, the ring body is provided with a stepped portion, or the screw is provided with a screw stepped portion, and the arrangement of the shape memory alloy washer is positioned and engaged at the center position of the shaft portion of the screw. Since the fastening work can be performed in a state, workability and efficiency when performing the fastening work are improved.

  When the ring body or the shape memory alloy washer has an uneven portion, the fastening body structure is in a state where the ring body and the shape memory alloy washer rotate along with the rotation of the screw, and the screw is the washer arm portion. The fastening part can be fastened to the installation part without expanding the width. In addition, when the fastening structure is disassembled, the concavo-convex portion does not interfere with the release of the shape memory alloy washer, so that disassembling workability is improved.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 is an exploded perspective view schematically showing the entire fastening body structure, FIGS. 2A and 2B are a sectional view showing a fastening body structure, a sectional view showing a dismantled state, FIG. b) is a bottom view and a side view schematically showing the concavo-convex portion formed in the ring body used in the fastening body structure, and FIGS. 4A to 4G are a fastening procedure and a disassembling procedure of the fastening body structure. They are the perspective view and side view which cut and show a part.

  As shown in FIG. 1 and FIG. 2A, the fastening body structure 1 uses a screw member 4 including a screw 2, a ring body 6, and a shape memory alloy washer 3. Is fastened to the installation part 20. The screw 2 here refers to a general pan screw, module screw, tapping screw or the like, and includes a male screw portion 2d continuous with the head portion 2a.

In the fastening body structure 1, the relationship between the screw 2, the ring body 6, the shape memory alloy washer 3, the screw hole 11 of the fastening part 10, and the installation portion 20 is shown in FIGS. 2 (a) and 2 (b). It has the arrangement and dimensions shown in. That is, the diameter D2 of the screw hole 11 of the fastening part 10 is larger than the diameter (outer diameter) D0 of the head 2a of the screw 2 and the diameter (outer diameter) D1 of the ring body 6, and is outside the shape memory alloy washer 3. It is formed smaller than the diameter D3. The inner diameter of the shape memory alloy washer 3 is formed to be smaller than the diameter D1 of the ring body 6 at normal temperature.
The female screw portion 21 formed in the installation portion 20 is formed so that the male screw portion 2d of the screw 2 can be screwed. As shown in FIG. 2B, the shape memory alloy washer 3 is stored in advance so that the inner diameter of the washer is larger than the diameter D1 of the ring body 6 when heated to the martensite transformation temperature or higher. .

  As shown in FIGS. 1 and 2 (a), the screw 2 includes a head 2a and a male screw portion 2d formed continuously on the head 2a via a shank 2c. Here, the screw 2 forms the lower surface of the head 2a on a horizontal surface. Further, the shank 2c of the screw 2 is a shaft portion that has a diameter substantially equal to that of the male screw portion 2d and is not formed with a thread, and when the ring body 6 described later is inserted, The length is equal to the height dimension. The male screw portion 2d is used in pairs with the female screw portion 21 provided in the installation portion 20 described later. The male screw portion 2d is formed so that its tip is pointed.

  As shown in FIG. 2 and FIG. 3, the ring body 6 includes an annular ring portion 6 </ b> A formed to have substantially the same diameter as the head portion 2 a of the screw 2, and the ring portion continuous with the ring portion 6 </ b> A. A cylindrical step portion 6B having a smaller diameter than 6A is integrally provided, and a through hole 6C is formed in communication with the center. The ring body 6 is formed such that the ring portion 6A has a diameter smaller than the diameter of the screw hole 11 of the fastening component 10 described later. The ring body 6 has a screw contact surface 6a that contacts the upper surface of the screw 2 on the upper surface of the ring portion 6A, and a washer contact surface 6b that contacts the shape memory alloy washer 3 on the lower surface of the ring portion 6A. ,have.

  And the screw contact surface 6a of the ring body 6 has the inclined surface formed in the direction approaching the washer contact surface 6b as it goes to a periphery in a radial direction. Here, the screw contact surface 6a is formed as an inclined surface having a clearance angle α of a predetermined inclination angle on the entire surface contacting the screw of the ring portion 6A. The clearance angle α is preferably set in the range of 10 to 30 degrees as shown in FIG.

  Further, as shown in FIG. 2A, the washer contact surface 6b of the ring body 6 has an inclination angle of a slant surface formed in a direction approaching the screw contact surface 6a toward the periphery in the radial direction (dish (Angle) θ is set to be in the range of 90 to 175 degrees. When the inclination angle θ of the washer contact surface 6b is within the above range, a predetermined tightening force is applied via the shape memory alloy washer 3 to fasten the fastening component 10 to the installation portion 20. Can be. Further, the shape memory alloy washer 3 is easily removed from the screw 2 at the time of disassembly. Therefore, in the ring portion 6A of the ring body 6, the inclination angle θ of the washer contact surface 6b is set in the range of 90 to 175 degrees. In addition, the inclination angle θ of the washer contact surface 6b is more preferably 100 to 170 degrees, and more preferably in the range of 110 to 150 in terms of both fastening properties and disassembly properties. 3A and 3B, the washer contact surface 6b of the ring body 6 is formed so that the entire surface of the washer contact surface 6b is inclined here.

  The step portion 6B of the ring body 6 is formed in a cylindrical shape and is sized to be disposed between the head portion 2a of the screw 2 and the male screw portion 2d, and is larger than the diameter of the male screw portion 2d. It is formed smaller than the diameter of the part 2a. The step 6B is for engaging the shape memory alloy washer 3 so that the shape memory alloy washer 3 does not easily fall off when the screw 2 is tightened. The shape memory alloy washer 3 is positioned in the center of the shaft portion. Although not shown in the figure, provisional attachment of the shape memory alloy washer 3 can be facilitated by providing a structure having a “collar” or “claw” at the lower end of the stepped portion 6B.

  As shown in FIGS. 1 and 2 (a), the shape memory alloy washer 3 is formed in a shape in which a notch is formed in a part of an annular shape and the washer arm portions on the left and right sides of the notch can be separated from each other. Here, the shape memory alloy washer 3 is formed in a substantially C-shape. The shape memory alloy washer 3 is formed such that the washer inner diameter portion is smaller and the washer outer diameter portion is larger than the diameter D2 of the screw hole 11 of the fastening component 10 described later. The washer 3 made of shape memory alloy has a washer inner diameter portion smaller than the diameter D1 of the head 2a of the screw 2, and the washer outer diameter portion is larger, and the diameter of the outermost diameter is D3 when fastened at room temperature. The washer inner diameter portion is formed to have a width dimension smaller than D1. The shape memory alloy washer 3 may be formed such that the positions of the washer arm portions are staggered in the vertical direction so that the spring action can be exerted. The shape memory alloy washer 3 exhibits a martensite phase at room temperature and can be easily deformed, and has a property of exhibiting an austenite phase and recovering a memorized shape at a temperature higher than the transformation temperature (martensite transformation temperature). An alloy composition in which the mixing ratio of various metals is adjusted according to the transformation temperature is used.

  A preferred shape memory alloy used for the shape memory alloy washer 3 includes a Ti—Ni alloy, and the Ni content in the alloy is 49.5 at% to 51.0 at% (atomic percent). Is preferred. Further, this Ti—Ni alloy may be an alloy containing at least one of Cu, Fe, Cr, V, Nb, Co and the like in an amount of 10 at% or less. For example, Ti—Ni—Cu An alloy is mentioned. Furthermore, Cu-type alloys, such as Cu-Al-Ni, Cu-Zn-Al, Cu-Al-Ni-Mn-Ti, Cu-Al-Mn, and Cu-Zn, may be sufficient. In addition, alloys such as Au—Cd, In—Ti, and Fe—Pt can also be used.

  When a Ti—Ni alloy is used for the shape memory alloy washer 3, the shape memory treatment is performed so that the inner diameter becomes D1 (see FIG. 2) or more at a temperature of 400 to 500 ° C. (for example, 450 ° C.), which is the transformation temperature or higher. (For example, a C-shape or arc having a notch [gap] formed in an annular body or an arc shape), and pressurizing to a predetermined inner diameter shape smaller than D1 required at the time of fastening at room temperature (normal temperature) ( For example, the notch [gap] is narrowed so that the inner diameter becomes C1 or less). For example, in the case of a shape memory alloy having a martensite transformation temperature of 75 to 100 ° C., the shape memory alloy washer 3 can be memorized by heating the shape memory alloy to a temperature of 75 to 100 ° C. or higher. As shown in FIG. 2 (b), the gap is enlarged to restore the washer inner diameter larger than the diameter of the head 2 a of the screw 2. Here, the shape memory alloy washer 3 is not subjected to any special surface treatment and is in a normal smooth surface state.

  The fastening component 10 includes a screw hole 11 having a diameter D2 formed larger than the head 2a diameter D0 and the ring diameter D1 of the screw 2. The fastening component 10 used here is made of metal or synthetic resin, and the surface thereof may be subjected to surface treatment such as painting or rust prevention. In the fastening component 10, a hole peripheral surface 12 that contacts the lower surface of the shape memory alloy washer 3 is set on the peripheral surface of the screw hole 11.

The installation part 20 is a part or part for fastening the fastening part 10 with the screw 2, and a female screw part 21 corresponding to the male screw part 2 d of the screw 2 is formed.
The female screw portion 21 has a configuration in which a screw is formed inside the cylindrical member, or a configuration in which a female screw portion is directly formed on a member of the installation portion 20. In FIG. 2, the female screw portion 21 is formed longer than the length of the male screw portion 2d of the screw 2. However, the length of the female screw portion 21 is shorter than or equal to that of the male screw portion 2d. It doesn't matter. In the case where a tapping screw is used, the installation portion 20 is not provided with the female screw portion 21.

Next, a fastening procedure and a disassembling procedure of the fastening body structure 1 will be described with reference to FIG. 2 as appropriate, focusing on FIGS. 4 (a) to 4 (d).
First, as shown to Fig.4 (a), according to the internal thread part 21 of the installation part 20, it is set as the arrangement | positioning state which connects the screw hole 11 of the fastening component 10 in communication.
4B, the ring body 6 is inserted into the screw 2 and the screw member 4 in which the shape memory alloy washer 3 is engaged with the ring body 6 is used. 10 is screwed. When screwing, if the shape memory alloy washer 3 is engaged with the step portion 6B of the ring body 6, workability at the time of fastening is improved.

  As shown in FIGS. 4C and 4D, the screw 2 is screwed with a driver Dr manually or by a robot hand or the like. At this time, the force (tightening torque) to be tightened by the screw 2 is, for example, in the range of 0.8 to 1.37 (N.m) for a screw (M4) having an outer diameter of 4 mm, and is usually 1.1 ( N.m).

  In the fastening body structure 1, when the screw 2 is tightened by the driver Dr, the screw contact surface 6a of the ring body 6 slips even if the head 2a rotates, and the ring body 6 rotates idle with respect to the rotation of the screw. It becomes. Therefore, in a state where the screw 2 is turned and the ring body 6 is idle, the shape memory alloy washer 3 abuts against the ring body 6 and presses the fastening part 10. That is, the rotating force when the screw 2 is screwed in is not applied to the shape memory alloy washer 3 via the ring body 6 to prevent the washer arm portion of the shape memory alloy washer 3 from spreading. is doing. Therefore, as shown in FIG. 4D, in the fastening body structure 1, when the screw 2 is turned, the washer arm portion is expanded by the shape memory alloy washer 3 pressed against the non-rotating ring body 6. Instead, the fastening part 10 is fastened to the installation part 20 with a predetermined torque by the screw 2, thereby realizing a firm fastening.

  Next, when the part is disassembled, as shown in FIG. 4 (e), during the operation of disassembling the part, the fastening body structure 1 including the shape memory alloy washer 3 is not less than a predetermined temperature higher than the martensitic transformation temperature. Put in the environment. For example, when hot air or superheated steam is blown near the shape memory alloy washer 3 or toward the shape memory alloy washer 3, the washer inner diameter portion tries to return to the shape memorized by the shape memory alloy washer 3. Is in a state in which the washer arm is expanded so that the diameter of the screw 2 is larger than the diameter of the head 2 a of the screw 2. At this time, since the washer contact surface 6b is an inclined surface, the washer arm portion is easily expanded and detached from the ring body 6.

Therefore, as shown in FIG. 4 (f), the shape memory alloy washer 3 is detached from the head 2 a of the screw 2.
And as shown in FIG.4 (g), when the shape memory alloy washer 3 (only one is described in a figure) of all the installation locations slips out, it will be in the state from which the fastening component 10 will remove | deviate from the installation part 20, and the installation part 20 As a result, the fastening component 10 is separated.
Thereafter, the screw 2, the shape memory alloy washer 3, the fastening part 10, and the installation part 20 are in a disassembled state by rotating the screw 2 from the installation part 20 with a driver Dr. Alternatively, when the installation part 20 is made of synthetic resin, the screw 2 and the ring body 6 may be recovered from the pulverized product after mechanically pulverizing the installation part 20 with the screws 2 attached.

  As described above, in the fastening body structure 1, the shape memory alloy washer 3 is pressed by the screw 2 through the ring body 6, and the washer arm portion of the shape memory alloy washer 3 is not expanded. The fastening component 10 can be fastened to the installation portion 20 with a desired tightening torque, and the shape memory alloy washer 3 can be detached from the screw 2 at the time of disassembly to facilitate removal of the fastening component 10.

1 to 4, the ring body 6 is described as having a stepped portion 6B. However, for example, a configuration as shown in FIG. 5 may be used. In addition, the already demonstrated structure attaches | subjects the same code | symbol and abbreviate | omits description.
As shown in FIG. 5, the screw member 4 </ b> A of the fastening body structure 1 </ b> A includes a screw 2 </ b> A, a ring body 16, and a shape memory alloy washer 3. The screw 2A is a screw step formed in a columnar shape having a diameter smaller than the outer diameter of the head 2a and larger than the outer diameter of the male screw 2d between the head 2a and the male screw 2d. 2C is provided. The length dimension of the screw step 2C is formed to be longer than the total thickness of the ring body 16 and the shape memory alloy washer 3. Moreover, the ring body 16 is comprised by the cyclic | annular form which has the substantially same outer diameter as the head 2a. Furthermore, the through-hole (insertion hole) 16B is formed in the ring body 16, and as already described, the screw contact surface 16a and the washer contact surface 16b are provided. The shape memory alloy washer 3 is inserted into the outer periphery of the screw step portion 2C at a position below the ring body 6, and is temporarily attached and positioned.

  In this way, as shown in FIG. 5, the screw member 4A has the screw step 2C formed on the screw 2A, and the ring body 16 and the shape memory alloy washer 3 are inserted therein. Is rotated, the shape memory alloy washer 3 is pressed in a state where the ring body 16 is idle with respect to the rotation of the screw 2A. Therefore, the screw member 4 </ b> A can fasten the fastening component 10 to the installation part 20. Further, at the time of dismantling, the shape memory alloy washer 3 expands the washer arm portion and is easily detached from the screw 2A.

  As described above, the fastening body structure 1A makes it difficult to give the shape memory alloy washer 3 the force to expand the washer arm portion via the ring body 16, and thus exhibits a predetermined tightening torque. It becomes possible to fasten the fastening component 10 to the installation part 20 in a state in which the ease of disassembling is ensured at the time of disassembling.

  Further, when the ring body 6 (16) is used, the shape memory alloy washer 3 is formed by providing the concave and convex portion 5 as shown in FIG. 6 on the washer contact surface 6b of the ring body 6 (16). It is also possible to make it more difficult to expand the washer arm portion when fastening. In addition, the already demonstrated structure attaches | subjects the same code | symbol and abbreviate | omits description.

  As shown in FIG. 6, the concave-convex portion 5 is formed with triangular convex portions 5 a and concave portions 5 b having a constant width radially from the periphery of the ring body 6 toward the center (or from the center to the periphery). Here, the concavo-convex portion 5 is formed such that the convex portion 5a and the concave portion 5b are continuously formed in the circumferential direction of the washer contact surface 6b. In this uneven portion 5, the height dimension from the top of the convex portion 5 a to the bottom of the concave portion 5 b is set in the range of 0.05 to 0.25 mm. In addition, the number of the circumferential direction of the convex part 5a is although it does not specifically limit, It is preferable to set as a range of 12-42 mountains (a particularly preferable range is 20-36 mountains). Moreover, the convex part 5a is formed toward the center from the periphery of the washer contact surface 6b at a fixed height. In addition, when the shaft diameter of the screw 2 exceeds M4.0, it is preferable to suppress the expansion of the washer arm portion by interposing the ring body 6. The concavo-convex portion 5 may be formed by knurling with a predetermined processing means such as forging.

  When the ring body 26 in which the concavo-convex portion 5 is formed is used, the concavo-convex portion 5 of the ring body 26 is engaged (hooked) with the washer contact surface 6b, so that the ring body 6 and the shape memory alloy are made. An attempt is made to suppress the force that the shape memory alloy washer 3 tries to spread by the rotation of the washer 3. That is, the rotating force when the screw 2 is screwed is not applied to the shape memory alloy washer 3 so that the washer arm portion of the shape memory alloy washer 3 does not expand. For this reason, in the fastening body structure 1B, when the screw 2 is turned, the ring body 26 rotates idle, or even if the ring body 26 rotates together with the screw, the shape memory alloy washer 3 is also simultaneously provided by the uneven portion 5. The washer 3 made of shape memory alloy is pressed against the hole peripheral surface 12 of the fastening part 10, and the fastening with the screw 2 can be realized without expanding the washer arm portion.

In addition, the shape of the concavo-convex portion 5 used in the fastening body structure 1B is such that the shape of the convex portion 5a and the concave portion 5b is both triangular and is continuous with a constant width in the circumferential direction of the washer contact surface 6b of the ring body 6. Although described, for example, the configuration shown in FIGS. In addition, the structure already demonstrated in FIGS. 7-11 attaches | subjects the same code | symbol, and abbreviate | omits description.
That is, as shown in FIG. 7 (a), the trapezoidal convex portion 5c and the concave portion 5d are configured to be continuous in the ring circumferential direction, and as shown in FIG. The configuration may be such that the sawtooth-shaped convex portion 5e that is formed obliquely by a predetermined angle and the concave portion 5f that is between the convex portions 5e are continuous in the ring circumferential direction. As described above, the convex portions 5c and 5e may have any shape as long as an edge (corner portion) is formed. Furthermore, the convex portion 5e and the concave portion 5f may have different shapes (for example, the concave portion is a flat portion).

  Further, the intervals between the convex portions 5a and the concave portions 5b formed in the same shape of the concavo-convex portion 5 may be equal intervals as shown in FIG. 7, or may be configured as shown in FIG. That is, as shown in FIG. 8A, the convex portions 5a and the concave portions 5b are formed at regular intervals via the flat portion 7, or as shown in FIG. 8B, the convex portions 5a. May be formed independently by the flat portion 7, and the convex portion 5 a and the concave portion 5 b may be continuous and spaced apart by the flat portion 7. Thus, when the shape of the convex part 5a and the recessed part 5b is the same shape, the convex part 5a can be independently formed at predetermined intervals via the flat part 7, or the convex part 5a and the concave part can be formed. 5b may be formed at predetermined intervals via the flat portion 7, or may be formed as a combination thereof.

  Furthermore, the formation direction of the concavo-convex portion 5 has been described as a configuration in which it is formed continuously from the center of the ring body 6 to the periphery and in the circumferential direction of the ring body 6 in FIG. 6, but as shown in FIG. It may be a simple configuration. That is, as shown in FIG. 9A, the uneven portion 15 formed on the washer contact surface 6b of the ring portion 6A is formed in a spiral shape at a predetermined inclination angle from the center of the ring portion 6A toward the periphery. In addition, as shown in FIG. 9B, the concavo-convex portion 25 includes a radial convex portion 25a (or concave portion 25b) from the center of the ring portion 6A toward the peripheral edge, and the radial convex portion 25a (or Convex portions 25ac and 25ac (or concave portions 25bc) are formed as a set which are line symmetrical with respect to the left and right of the concave portion 25b) and are arranged at a predetermined angle in a direction away from the convex portion 25a at the center toward the periphery. The configuration may be such that one set is provided in the circumferential direction of the ring portion 6A. As described above, the direction in which the concave and convex portions 15 and 25 are formed is a direction in which the ring body 6 and the shape memory alloy washer 3 are rotated, and the result is an operation in which the washer arm portion of the shape memory alloy washer expands during disassembly. It doesn't matter as long as it doesn't get in the way.

  And the installation length of the convex part 5a and the recessed part 5b is provided with the fixed width | variety continuously from the inner diameter side of the ring body 6 to the outer periphery side in FIG. 6, but as shown in FIG. It may be a simple configuration. That is, as shown to Fig.10 (a), it is set as the structure which forms the convex part 35a so that it may be formed in the washer contact surface 6b contact | abutted to the washer 3 made from shape memory alloy. That is, the convex part 35a is good also as a structure radially formed toward the periphery from the center of the ring part 6A between the step part 6B side and peripheral side of the ring part 6Aa. Further, as shown in FIG. 10 (b), the convex portion 45a has an annular area in the circumferential direction which is the central side of the ring portion 6A on the washer contact surface 6b of the ring portion 6A, and an annular shape which is in the circumferential direction on the peripheral side. It is arranged for every three annular areas of the area and the annular area between the annular area on the center side and the annular area on the peripheral side. And you may comprise the convex part 45a so that it may be in the state arrange | positioned spirally with respect to the circumferential direction of the head 2a. In addition, in FIG. 10, the flat part is made into the recessed parts 35b and 45b. Thus, the installation lengths of the convex portions 35a and 45a and the concave portions 35b and 45b are the directions in which the ring body 6 and the shape memory alloy washer 3 are provided when the screw 2 is rotated, and are made of the shape memory alloy at the time of disassembly. Any installation length that does not interfere with the movement of the washer arm of the washer 3 as a result may be used.

  Moreover, in FIG. 6, although the width | variety in which the uneven | corrugated | grooved part 5 is formed toward the periphery from the center of the head 2a was demonstrated as a fixed space | interval, the structure as shown in FIG. 11 may be sufficient. In other words, as shown in FIG. 11, the concavo-convex portion 55 is formed by alternately forming a convex portion 55 a having a triangular cross section and a concave portion 55 b that is a flat portion in the circumferential direction. And the convex part 55a is formed so that a width dimension and a height dimension may become small toward an outer periphery from an internal diameter side. Here, the flat portion between the two convex portions 55a and 55a is defined as the concave portion 55b.

  As described above with reference to FIGS. 6 to 11, the configuration of the concavo-convex part is formed from the inner diameter side toward the outer diameter side, and the convex part and the concave part are installed along the circumferential direction. What is necessary is just to be in a state where the edge portion of the convex portion engages (hangs) with the shape memory alloy washer 3. That is, the structure of the concavo-convex portion is such that when the screw is screwed in by a screwdriver or the like, the ring body and the shape memory alloy washer are rotated even if the ring body rotates, and the fastening part 10 is rotated by a torque exceeding a predetermined value. The configuration is not limited as long as it can be fastened and the shape memory alloy washer 3 is easily detached from the screw 2 at the time of disassembly.

  Further, in the description of FIGS. 6 to 11, the configuration has been described in which the concavo-convex portion 5 is provided on the washer contact surface 6 b of the ring body 6, but instead of being formed on the ring body 6, as shown in FIG. The uneven portion 50 may be formed on the ring contact surface 51 that contacts the ring body 6 of the alloy washer 3. When the concave and convex portion 50 is provided in the shape memory alloy washer 3, a cut having a triangular cross section is formed radially in the washer circumferential direction to form the concave portion 50b, and the convex portion 50a is formed between the concave portions 50b and 50b.

In this example, the concave portion 50b is formed on the ring contact surface 51 of the shape memory alloy washer 3, thereby forming the convex portion 50a. However, the convex portion 50a is formed on the ring contact surface 51 of the shape memory alloy washer 3. The part 50a may be configured as a protrusion (not shown). As shown in FIGS. 7 to 11, the convex portion 50 a and the concave portion 50 b have shapes, installation intervals, installation widths, installation lengths, and installation heights that are the same as the ring body 6 when the screw 2 is turned. Especially, if the configuration is such that the memory alloy washer 3 can be rotated to fix the fastening part 10 to the installation part 20 and the shape memory alloy washer 3 can be detached from the ring body 6 at the time of disassembly. is not.
Furthermore, although the screw contact surface 6a and the washer contact surface 6b have been described as a configuration in which the entire surface is inclined as an inclined surface, a configuration in which a part thereof is inclined may be employed. In addition, the screw 2 has been described with its tip pointed, but the tip shape may be flat or curved, and is not particularly limited. The male thread 2d is formed on the screw 2 via the shank 2c. However, the shank 2d may be omitted and the male thread 2d alone may be used.
Further, the ring body 6 (16) may have a diameter larger than that of the head 2a of the screw 2, and the relationship between the shape memory alloy washer 3 and the screw hole 11 of the fastening component 10 may be established. In view of economics, it is desirable that the head is formed smaller than the head 2a.
Furthermore, the ring body 6 (16) may be formed so as to be slippery by polishing its surface with a polishing means such as buffing.

Next, the present invention will be described through examples, but the present invention is not limited to the following examples.
As the screw 2, a steel pan screw (M4) having an outer diameter of the head 2a of 7 mm, a screw diameter of 4 mm, and a screw length of 20 mm was used. In addition, the ring body 6 has three types in which the screw contact surface 6a has an inclination angle α of 10 degrees and the washer contact surface 6b has an inclination angle θ of 20 degrees, 25 degrees, and 30 degrees, respectively. . Further, the ring body 6 was formed with a step portion, the diameter of the step portion was 5 mm, and the length of the step portion was 2 mm.

  Further, a Ti—Ni alloy having a transformation temperature of 95 ° C. was formed into a wire by a normal drawing process, and thereafter, the wire was rolled up and down with a rolling mill to obtain a wire. Further, by pressing or the like, the wire having a flat cross section with a flat surface of 1.4 mm and a side surface of 1.0 mm was formed into a flat wire, and the wire was rolled into a C-shape to obtain a shape memory alloy washer 3. The formed shape memory alloy washer 3 was used in a state of being inserted into and engaged with the step portion of the ring body 6.

On the other hand, three test pieces made of hardened steel equivalent to S45C and having a size of 45 mm wide × 110 mm long × 10 mm thick were prepared. The test piece is provided with 10 countersunk holes with a 7.5 mm hole diameter from the surface to a depth of 4 mm from the surface, and a female screw with an inner diameter of φ4.0 mm below the counterbore. Formed.
Ten types of three screws 2 each fitted with a ring body 6 and a shape memory alloy washer 3 were prepared, and tightening work was sequentially performed with an electric screwdriver under the following conditions.

  That is, the screw 2 in a state in which the shape memory alloy washer 3 is engaged with each of the 10 holes provided in each test piece is tightened at 10 locations with a torque value of 1.1 (Nm), and the fastening state is established. Was observed. As a result, the expansion of the washer arm portion was suppressed to 0.3 mm or less from the initial setting at all 30 positions, and a secure fastening state was realized. From this, it was found that when the ring body 6 inserted into the screw 2 is used together, the screw is firmly tightened even if the screw is fastened with a strong torque.

  As a reference example, the ring body 6 is not used, and a 4 mm diameter screw having the same shape as that shown in FIG. 5 is used except for the 25-degree countersunk screw provided on the screw head. In the configuration, a fastening test was performed at 10 locations using the same members as in the configuration of the example. As a result, when the screw 2 was screwed in any part, the countersunk screw entered the inner diameter side of the shape memory alloy washer 3 and the washer arm portion was expanded, and a firm fastening state could not be secured.

  Next, hot air at 100 ° C. was blown to the fastened shape memory alloy washer by a dryer to confirm whether the shape memory alloy washer 3 was completely detached from the ring body 6, and the results are shown in Table 1. In Table 1, “○” indicates that it has completely detached, and “△” indicates that it has fallen between the screw hole of the test piece and the screw 2 without being completely removed, and the head of the screw. Those which did not leave the part were shown as “x”. In Table 1, “Δ” was evaluated as a pass rate of 50%.

  As shown in Table 1, most of the shape memory alloy washers 3 were detached from the ring body 6 during heating. Thus, by using the ring body 6 together, it is possible to fasten with a predetermined tightening torque value at the time of fastening, and further, the shape memory alloy washer 3 can be reliably detached from the ring body at the time of heating.

It is a disassembled perspective view which shows typically the fastening body structure which concerns on this invention. (A), (b) is sectional drawing of the fastening body structure which concerns on this invention, and sectional drawing which shows the state decomposed | disassembled. (A) is a bottom view which shows the lower surface of the ring body used for the fastening body structure which concerns on this invention, (b) is a side view of the ring body of the screw used for the fastening body structure which concerns on this invention. (A)-(g) is a side view or perspective view which notches and shows a part about the fastening procedure and disassembly procedure of the fastening body structure concerning this invention. (A), (b) is a decomposition | disassembly side view which cuts off a part of other structure of the ring body of the fastening body structure which concerns on this invention, and shows it typically. It is a disassembled perspective view which shows typically the state which provided the uneven | corrugated | grooved part in the ring body of the fastening body structure which concerns on this invention. (A), (b) is a schematic diagram which shows typically the other shape of the uneven | corrugated | grooved part in the ring body of the fastening body structure which concerns on this invention. (A), (b) is a schematic diagram which shows typically the other structure of the convex part of the uneven | corrugated | grooved part in the ring body of the fastening body structure which concerns on this invention, or the installation space | interval of a convex part and a recessed part. (A), (b) is a bottom view which shows typically the other structure of the formation direction in the uneven | corrugated | grooved part of the ring body of the fastening body structure which concerns on this invention. (A), (b) is a bottom view which shows typically the other structure of the installation length of the convex part in the uneven | corrugated | grooved part of the ring body of the fastening body structure which concerns on this invention. It is a bottom view which shows typically the other structure about the installation width | variety of the convex part in the uneven | corrugated | grooved part of the ring body of the fastening body structure which concerns on this invention. It is a disassembled perspective view which shows typically the other structure of a fastening body structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fastening body structure 2 Screw 2a Head 2b Inclined surface 2c Shank 2d Male screw part 3 Shape memory alloy washer 4 Screw member 5 Concave and convex part 5a Convex part 5b Concave part 6 Ring body 6A Ring part 6B Step part 6C Through hole 6a Screw contact Contact surface 6b Washer contact surface 10 Fastening component 11 Screw hole 12 Hole peripheral surface 20 Installation portion 21 Female screw portion

Claims (5)

A screw having a head on one end side of the male screw portion, a shape memory alloy washer formed in a shape corresponding to the screw and having a shape in which an annular part is cut off by the shape memory alloy, and the shape memory alloy A fastening body structure in which a fastening member is fastened to an installation portion by using a screw member that includes an annular ring body that is inserted and disposed in the male screw portion between a washer and a screw head. And
The shape memory alloy washer is formed such that the inner diameter is greater than the outer diameter of the head of the screw at a shape restoration temperature or higher of the material,
The fastening part has a screw hole, and the screw hole is formed to have a diameter larger than that of the screw head and the ring body, and a diameter smaller than a washer outer diameter of the shape memory alloy washer,
The ring body has a washer contact surface that contacts the shape memory alloy washer on one surface thereof, and a screw contact surface that contacts the lower surface of the head of the screw on the other surface,
The fastening body structure characterized in that the washer abutting surface includes an inclined surface that inclines in a direction approaching the screw abutting surface as it goes toward the ring periphery in the diameter direction.   The said ring body is provided with the inclined surface which inclines in the direction approaching the said washer contact surface as the said screw contact surface goes to the ring periphery in a diameter direction. Fastened body structure. The ring body includes a ring portion having the washer contact surface and the screw contact surface, and a step portion formed in a cylindrical shape continuously on the washer contact surface side of the ring portion,
The fastening structure according to claim 1, wherein the step portion is formed to have a smaller diameter than the ring portion and a diameter larger than the diameter of the male screw portion. The screw includes a cylindrical screw step between the head and the male screw portion, the diameter of which is smaller than the head and larger than the male screw portion.
The ring body has a screw contact surface and a washer contact surface that contacts the shape memory alloy washer, and includes an insertion hole that can be inserted into a screw step portion of the screw.
The fastening body structure according to claim 1 or 2, wherein the screw step portion is formed to have a length dimension equal to or greater than a total thickness of the ring body and the shape memory alloy washer.   An uneven portion is provided on one of the washer contact surface of the ring body or the ring contact surface of the shape memory alloy washer, and the uneven portion is from the inner diameter side of the ring body toward the outer shape side, or The fastening body structure according to claim 1, wherein a convex portion and a concave portion are formed from the inner diameter side to the outer shape side of the shape memory alloy washer.

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