JP2004316781A - Fastening structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for enabling easy disassembly of a product with low costs by using a well-known screw. <P>SOLUTION: A screw-shaft 11 is inserted into a screw inserting hole 31 of an object member 3 of fastening in a fastening structure, and the object member 3 and a base material 4 are fastened by screwing the screw shaft 11 into the base material 4 so that a screw head 12 is brought into press contact with the member 3 via a washer 2. The washer 2 is made of a shape-memory material so as to recover its shape when heating the material to shape-recovering temperature and make the bore of the washer 2 larger than an outer diameter of the screw head 12. Further, the screw inserting hole 31 is formed larger than the diameter of the screw head 12. A projecting portion is preferably formed at least on one face between contact-faces with the screw head 12 or the member 3 in the washer 2. A shape-memory alloy or a shape-memory resin is used as the shape-memory material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fastening structure using screws widely used in various fields, and particularly to a fastening structure suitable for application to recycled products such as televisions, refrigerators, washing machines, and air conditioners.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, screws are generally used for fastening parts such as electric appliances. As a conventional example for facilitating disassembly of a component fastened by using a screw as described above, the following fastening structure has been adopted.
[0003]
The screw is made of a shape memory alloy such as a Ti-Ni alloy, and the outer diameter of the male screw forming part at the time of the shape memory processing of the screw is formed smaller than the inner diameter of the female screw part with which the formed male screw is screwed. And, by forming a male thread portion screwed to the female thread portion by plastic deformation, by providing screws, bolts and nuts that can be easily disassembled, labor and cost during disassembly are reduced, and recycling is facilitated. (See, for example, Patent Document 1).
[0004]
By the way, in the above-mentioned Patent Document 1, the fact that the screw returns to the shape stored in shape by heating and the fastening is released is utilized. In this case, the number of screw members is one (male screw), and the purpose is to perform heat separation between the male screw and the female screw (nut) using shape memory characteristics. In this case, from the relationship between the crest diameter and the trough diameter of the screw, the strain recovery required to separate the male screw from the female screw (nut) is about 20%. However, the Ti-Ni alloy (strain recovery 8%) ) Is only 16% (8% × 2) even if it is used for male and female threads. For this reason, the screw cannot actually be easily removed, making it difficult to disassemble.
[0005]
In order to solve such a problem, the present applicant has proposed a fastening structure described in Japanese Patent Application No. 2002-223409.
[0006]
For example, as shown in FIG. 6, a screw a is formed by a first member b including a shaft b1 made of a shape memory material and a head b2, and a thread c1 formed in a cylindrical shape on an outer peripheral surface. And a second member c having That is, the screw a is formed by inserting the second member c into the shaft portion b1 and fixing the two members, and as shown in FIG. The two members are fastened by being inserted into the insertion hole d1 and screwed into the other member e.
[0007]
Then, the diameter of the shaft portion b1 of the first member b is reduced by heating, whereby the first member b is removed from the second member c and separated, so that one member d and the other member e can be easily separated. We are trying to dismantle.
[0008]
[Patent Document 1]
JP-A-8-61346 [0009]
[Problems to be solved by the invention]
However, in the case of the screw a described above, in principle, the first member b only needs to be made of a shape memory material at a portion of the shaft portion b1 that needs to be deformed at a minimum at the time of heating. In order to simplify the production process, it is desired that the entire first member b is made of a shape memory material and integrally formed.
[0010]
On the other hand, since the shape memory material is generally expensive, if the entire first member b is made of the shape memory material, there is a problem that the price of the screw increases.
[0011]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique that can use a conventionally well-known screw and can easily disassemble a product at low cost. .
[0012]
[Means for Solving the Problems]
According to the present invention, the screw shaft portion is inserted into the screw insertion hole formed in the member to be fastened, and the screw shaft portion is screwed into the base material so that the screw head is pressed against the member to be fastened via the washer. A fastening structure for fastening the member to be fastened and the base material, wherein the washer is shape-restored when heated to a shape-recovering temperature, and has a shape memory whose inner diameter is larger than the outer diameter of the screw head. On the other hand, a fastening structure is obtained in which the screw insertion hole is formed larger than the diameter of the screw head.
[0013]
Further, according to the present invention, the screw shaft portion is inserted into a screw insertion hole formed in the member to be fastened, and the screw shaft portion is pressed against the member to be fastened via a washer so that the screw shaft portion is formed on the base material. A fastening structure for fastening a member to be fastened and a substrate by screwing, wherein the washer has a shape such that when heated to a shape recovery temperature, the shape of the washer recovers and its outer diameter becomes smaller than the diameter of the screw insertion hole. A fastening structure is obtained, wherein the fastening structure is made of a stored shape memory material, while the screw insertion hole is formed larger than the diameter of the screw head.
[0014]
The edge of the washer on the side in contact with the member to be fastened may be formed with a chamfer having at least a minimum diameter smaller than a diameter of the screw insertion hole.
[0015]
The surface of the washer on the side in contact with the member to be fastened may be formed with a stepped portion that can be inserted into the screw insertion hole.
[0016]
The washer may have a protrusion formed on at least one of the screw head and the surface in contact with the member to be fastened.
[0017]
The shape memory material may be a shape memory alloy.
[0018]
The shape memory material may be a shape memory resin.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing a first embodiment of the fastening structure of the present invention.
[0020]
This fastening structure is a structure in which the member 3 to be fastened and the base material 4 are fastened by using a conventionally well-known screw 1 having a screw shaft portion 11 and a screw head 12, and specifically, FIG. ), The screw shaft portion 11 is inserted into a screw insertion hole 31 formed in the member 3 to be fastened, and the screw head portion 12 is pressed against the member 3 to be fastened via the washer 2. 11 is screwed into the screw hole 41 of the base member 4 to fasten the member 3 and the base member 4 together.
[0021]
Here, the washer 2 is made of a shape memory material, the shape of which is recovered when heated to a shape recovery temperature, and the shape of which is stored so that its inner diameter becomes larger than the outer diameter of the screw head 12. .
[0022]
As the shape memory material, specifically, a shape memory alloy, a shape memory resin, or the like is used, and the washer 2 is manufactured by the following method or the like.
[0023]
When a shape memory alloy is used, a material punched into a desired shape from a sheet material made of a shape memory alloy is subjected to a shape memory treatment, and then a diameter is adjusted by plastic working, or powder metallurgy, sintering, or the like. A product formed into a desired shape by a method such as consolidation and melt casting is subjected to a shape memory process, and then plastically processed to adjust the diameter, and the like.
[0024]
When a shape memory resin is used, a material punched into a desired shape from a shape memory resin-made plate material, or a shape memory material molded into a desired shape by injection molding is heated and softened. In such a state, the diameter is adjusted by applying a deformation, and cooling is performed to maintain the shape, and the like.
[0025]
On the other hand, the screw insertion hole 31 is formed to be larger than the diameter of the screw head 12.
[0026]
The outer diameter of the washer 1 before shape recovery is larger than the diameter of the screw insertion hole 31 because the member 3 and the base member 4 are fastened by the screw 1 via the washer 2 as described above. Needless to say.
[0027]
With such a fastening structure, when the washer 2 is heated to a shape recovery temperature in a state where the member to be fastened 3 and the base material 4 are fastened as shown in FIG. The inner diameter becomes larger than the diameter of the screw head 12 of the screw 1 (see FIG. 1B). When the shape of the washer 2 is recovered by heating as described above, the screw 1 may be slightly loosened.
[0028]
Therefore, by extracting the member 3 from the screw head 12 through the screw insertion hole 31 larger than the diameter of the screw head 12, the member 3 can be easily removed from the base material 4 as shown in FIG. This makes it possible to easily disassemble a product adopting such a fastening structure at low cost. That is, the product can be easily disassembled.
[Second embodiment]
FIG. 2 is a view showing a second embodiment of the fastening structure of the present invention.
[0029]
This fastening structure uses a washer 5 instead of the washer 2 described in the first embodiment described above. The washer 5 is made of the same shape memory material as the washer 2 described above, and is heated to a shape recovery temperature. The one whose shape is memorized so that its shape is recovered and its outer diameter becomes smaller than the diameter of the screw insertion hole 31 is used.
[0030]
Also, the screw insertion hole 31 is formed larger than the diameter of the screw head 12 similarly to the first embodiment, and the other configuration is also the same as that of the first embodiment. The same members as those described above are denoted by the same reference numerals and description thereof will be omitted.
[0031]
The outer diameter of the washer 1 before shape recovery is larger than the diameter of the screw insertion hole 31 because the member 3 and the base member 4 are fastened by the screw 1 via the washer 2 as described above. Needless to say.
[0032]
With such a fastening structure, when the washer 5 is heated to the shape recovery temperature in a state where the member 3 and the base member 4 are fastened as shown in FIG. The outer diameter is reduced and becomes smaller than the diameter of the screw insertion hole 31 of the screw 1 (see FIG. 2B). When the shape of the washer 2 is recovered by heating as described above, the screw 1 may be slightly loosened.
[0033]
Therefore, by extracting the member 3 from the screw head 12 through the screw insertion hole 31 larger than the diameter of the screw head 12, the member 3 can be easily removed from the base material 4 as shown in FIG. This makes it possible to easily disassemble a product adopting such a fastening structure at low cost. That is, the product can be easily disassembled.
[0034]
Further, in the case of the washer 5 whose shape is stored so that the outer diameter is reduced as shown in the second embodiment, as shown in FIG. What is necessary is just to provide the chamfered part 51 whose minimum diameter is smaller than the diameter of the screw insertion hole 31.
[0035]
By providing the chamfered portion 51 in this manner, (1) positioning of the washer 5 becomes easy. {Circle over (2)} The shape of the washer 5 when heated is heated in a direction in which the fastening force is relaxed, so that the shape can be easily recovered. {Circle around (3)} When the disassembly is performed after the heating, it is possible to obtain the effect that the washer 5 is hardly caught in the screw insertion hole 31 and is easily pulled out.
[0036]
Further, as shown in FIG. 4, a stepped portion 52 may be provided on the surface of the washer 5 on the side in contact with the member 3 to be fastened. The stepped portion 52 is preferably slightly smaller than the diameter of the screw insertion hole 31, and is formed to have the same diameter as the minimum diameter of the chamfered portion 51 in FIG. As a result, the mounting accuracy can be further improved, and the strength can be increased because the thickness can be increased by the stepped portion 52.
[0037]
Note that only the stepped portion 52 may be formed on the washer 5 without forming the chamfered portion 51.
[0038]
Further, in each of the first and second embodiments, as shown in FIG. 5, the protrusions 53 may be provided on the surfaces of the washers 2 and 5 which are in contact with the screw head 12 or the member 3 to be fastened, or on both surfaces thereof. Good. For example, four protrusions 53 may be provided radially at 90 ° intervals, as shown in FIG.
[0039]
By providing the projection 53 in this manner, the surface in contact with the screw head 12 or the member 3 to be fastened, or the contact area with both surfaces can be reduced, and the shape of the washers 2, 5 can be recovered with a lower load. It becomes possible.
[0040]
By the way, as the surface of the washer provided with the projection 53, the washers 2 and 5 shown in FIGS. 1 and 2 may be provided on the surface in contact with the screw head 12 or the member 3 to be fastened, or on both surfaces thereof. The washer 5 shown in FIGS. 3 and 4 may be provided on the surface in contact with the screw head 12. In other words, the protrusion 53 may be provided on at least one of the screw head 12 and the surface in contact with the member 3 to be fastened.
[0041]
The number and shape of the projections 53 are not limited to those shown in FIG. 5, and may be determined appropriately so as to obtain the above-described effects.
[0042]
【The invention's effect】
As described above, according to the present invention, when heated to the shape recovery temperature, the shape is recovered, and the shape memory material washer whose shape is stored so that the inner diameter thereof is larger than the outer diameter of the screw head, or the shape washer. When heated to the recovery temperature, the shape is recovered and the outer diameter is smaller than the diameter of the screw insertion hole. With this structure, the product can be easily disassembled at low cost using a conventionally known screw.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a first embodiment of a fastening structure according to the present invention, wherein FIG. 1 (a) is a side view showing a state in which a member to be fastened and a base material are fastened by screws via a washer before shape recovery. FIG. 4B is a cross-sectional side view showing a state where the shape of the washer is recovered by heating, and FIG. 4C is a side cross-sectional view showing a state where the member to be fastened and the base material are separated.
FIG. 2 is a view showing an example of a second embodiment of the fastening structure of the present invention, wherein FIG. 2 (a) is a side view showing a state where a member to be fastened and a base material are fastened by screws via a washer before shape recovery; FIG. 4B is a cross-sectional side view showing a state where the shape of the washer is recovered by heating, and FIG. 4C is a side cross-sectional view showing a state where the member to be fastened and the base material are separated.
FIG. 3 is a view showing an example of a second embodiment of the fastening structure of the present invention, and is a side cross-sectional view showing a state where the member to be fastened and the base material are fastened by screws via a washer before shape recovery. .
FIG. 4 is a view showing an example of a second embodiment of the fastening structure of the present invention, and is a side cross-sectional view showing a state where the member to be fastened and the base material are fastened by screws via a washer before shape recovery. .
FIG. 5 is a perspective view showing an example of a washer in the first and second embodiments of the fastening structure of the present invention.
FIG. 6 is a view showing an example of a conventional easily disassembled screw, in which (a) is a perspective view and (b) is a side sectional view.
FIG. 7 is a side cross-sectional view showing a state where the fastening target members are fastened using the conventional screw of FIG. 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Screw 11 Screw shaft part 12 Screw head 2 Washer 3 Fastened member 31 Screw insertion hole 4 Base material 5 Washer 51 Chamfered part 52 Stepped part 53 Projection part

Claims (7)

The screw shaft is inserted into a screw insertion hole formed in the member to be fastened, and the screw shaft is screwed into the base material so that the screw head is pressed against the member to be fastened via a washer. A fastening structure for fastening the material
The washer is made of a shape memory material whose shape is memorized so as to recover its shape when heated to a shape recovery temperature and its inner diameter becomes larger than the outer diameter of the screw head, while the screw insertion hole has a screw head. A fastening structure characterized by being formed larger than the diameter of the portion. The screw shaft is inserted into a screw insertion hole formed in the member to be fastened, and the screw shaft is screwed into the base material so that the screw head is pressed against the member to be fastened via a washer. A fastening structure for fastening the material
The washer is made of a shape memory material whose shape is memorized such that the shape of the washer recovers when heated to a shape recovery temperature and its outer diameter becomes smaller than the diameter of the screw insertion hole, while the screw insertion hole is formed of the screw. A fastening structure characterized by being formed larger than the diameter of the head. 3. The fastening structure according to claim 2, wherein a chamfered portion having at least a minimum diameter smaller than a diameter of the screw insertion hole is formed at an edge of the washer on a side contacting the member to be fastened. 4. The fastening structure according to claim 2, wherein a stepped portion that can be inserted into the screw insertion hole is formed on a surface of the washer on a side that contacts the member to be fastened. The fastening structure according to any one of claims 1 to 4, wherein the washer has a projection formed on at least one of a surface of the washer and a surface in contact with the member to be fastened. The fastening structure according to claim 1, wherein the shape memory material is a shape memory alloy. The fastening structure according to any one of claims 1 to 5, wherein the shape memory material is a shape memory resin.

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