JPH0861346A - Screw, bolt, and nut - Google Patents

Abstract

PURPOSE: To reduce the labor and cost in dismantlement and facilitate recycle by providing a screw, bolt and a nut for facilitating dismantlement. CONSTITUTION: A screw is made of the shape memory alloy such as Ti-Ni alloy. The outside diameter d0 of the male screw formation part 12A in the shape memory treatment of this screw is set smaller than the inside diameter d1 of the female screw part with which the male screw part 12B after shaping is meshed. Then, the male screw part 12B screwed with the female screw part is formed through the plastic de formation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to screws, bolts and nuts used for fastening objects to each other, such as for assembling parts into a main body.

[0002]

2. Description of the Related Art Conventionally, brass and stainless screws, or bolts and nuts are generally used when fastening objects to each other such as assembling parts into a main body.
The two objects were fastened by turning a screw or a bolt in a tightening direction manually or by a machine.

When it is necessary to separate the two fixed objects for repair or recycling, use a hand or a machine to turn the screws or bolts in the direction of loosening them to separate the two objects. Was there.

[0004]

Such screws, bolts and nuts are very effective for closely adhering and fixing two objects and are widely used. Therefore, depending on the product, tens to hundreds may be used.

By the way, in recent years, there has been a strong demand for recycling of products, and it has become necessary to effectively utilize the parts and members used in the products. However, in order to separate and separate products by parts or by different materials, used screws or bolts and nuts must be removed one by one. This consumes a very large amount of labor (labor costs, etc.) and time, which is a great burden.
This will increase dismantling costs and costs for the next product.

Further, the user may accidentally loosen and remove the screws, bolts and nuts used in the product. In some cases, the removal may pose a danger to the user, or the performance or function of the product may be changed or deteriorated. As described above, depending on the product, in order to prevent the danger to the user or to maintain the performance, it may be necessary to prevent the screw or bolt once tightened from coming off again, or the user may arbitrarily remove the screw or bolt. It may be bad to remove it.

However, the conventional screws and bolts can be easily removed by the user with a screwdriver or spanner.

Therefore, the present invention has been made to solve the above problems, and a first object thereof is to provide a screw, a bolt and a nut which can be easily disassembled so that the labor and cost at the time of dismantling can be improved. And to facilitate recycling.

A second purpose is to prevent the user from avoiding danger and to maintain product performance by preventing the screw or bolt once tightened from being accidentally loosened or preventing the screw or bolt once tightened from loosening. It is to plan.

[0010]

According to a first aspect of the present invention, there is provided a screw or a bolt made of a shape memory alloy, wherein the outer diameter of the male screw forming portion at the time of shape memory processing is after the formation. The inner diameter of the male screw portion is smaller than the inner diameter of the female screw portion with which the male screw portion is screwed, and the male screw portion that is screwed with the female screw portion by plastic deformation is formed.

According to a fifteenth aspect of the present invention, there is provided a nut made of a shape memory alloy, wherein the inner diameter of the female screw forming portion at the time of shape memory processing is screwed into the female screw portion after the formation. It is formed to be larger than the outer diameter of the portion, and a female screw portion to which the bolt side male screw portion is screwed by plastic deformation is formed.

The invention according to claim 2, 9 or 16 has a transformation temperature of these shape memory alloys of 75 ° C to 110 ° C.
It is set at ℃.

The invention according to claim 3, 10 or 17 uses a Ti-Ni alloy as the shape memory alloy.

The invention according to claim 4, 11 or 18 is characterized in that the composition of the Ti-Ni alloy is Ti-49.5 at.
% Ni to Ti-50.1 at% Ni.

According to the invention of claim 5, 12 or 19, the above-mentioned Ti-Ni alloy is worked and hardened by a cold working method to form into a predetermined shape, and then 350 ° C.
It was subjected to a medium-temperature treatment of storing at a temperature of up to 500 ° C.

Further, in the invention according to claim 6, 13 or 20, the above-mentioned Ti-Ni alloy is preheated to 800 ° C or higher to normalize the structure, and molded into a predetermined shape at room temperature. After that, a low temperature treatment for performing a memory treatment at a temperature of 200 ° C. to 300 ° C. is performed.

In the invention according to claim 7, 14 or 21, as the shape memory alloy, a Cu-Al-Ni alloy,
Alternatively, a Cu-Zn-Al alloy is used.

On the other hand, the invention according to claim 22 or 29,
A screw or a bolt made of a shape memory alloy, which is subjected to shape memory processing in a state where the tightening portion is not formed on the screw head, and then the tightening portion is formed on the screw head by plastic deformation.

The invention according to claim 23 or 30 is
A screw or a bolt made of a shape memory alloy, which is formed by subjecting a thread shape to a shape memory treatment in a distorted state from a standardized shape, and then plastically deforming it to the standardized shape.

In the invention according to claim 24 or 31, the transformation temperature of these shape memory alloys is -150 ° C to 0.
It is set at ℃.

The invention according to claim 25 or 32 is
A Ti-Ni alloy is used as the shape memory alloy described above.

Further, in the invention according to claim 26 or 33, the composition of the above Ti-Ni alloy is Ti-50.9 at.
% Ni to Ti-51.5 at% Ni.

The invention according to claim 27 or 34,
After the solution heat treatment of the above-mentioned Ti—Ni alloy at 800 ° C. to 1000 ° C., the alloy is rapidly cooled at a temperature of about 400 ° C.
It has been subjected to a high temperature treatment in which it is aged and heated for more than an hour.

The invention according to claim 28 or 35,
As the shape memory alloy, a Cu-Al-Ni alloy or a Cu-Zn-Al alloy is used.

[0025]

According to the structure of claim 1 or claim 8, when such a screw or bolt is used to assemble each part or member into a product, the screw or bolt is returned to a shape memory state at a transformation temperature. Just put the product in the above environment,
Each screw and bolt can be removed without human intervention. In this way, a large number of screws and bolts can be removed at one time, so that disassembly (separation, separation) of products can be facilitated. It is also effective when it is desired to release the tightening with screws or bolts at a certain temperature, and for example, it can have a role as a switch for removing the screws or the bolts at a certain temperature. As a result, a person does not have to intervene to remove the screws and the bolts, so that the screws and the bolts can be removed or the switch can be turned on or off by remote control by temperature adjustment.

According to the structure of claim 15, a nut made of a shape memory alloy is used in the same manner as described above, and by assembling each part or member into a product, each nut is returned to a shape memory state or higher than a transformation temperature. By simply placing the product under the environment, each nut can be removed without human intervention. In this way, you can remove a lot of nuts at once,
The dismantling (separation, separation) of products can be facilitated. It is also effective when it is desired to release the tightening by the nut at a certain temperature, and for example, it can be provided with a role of a switch for releasing the nut at a certain temperature. This eliminates the need for human intervention to remove the nut,
The nut can be removed or the switch can be turned on or off by remote control with temperature adjustment.

Further, according to the structure of claim 2, 9 or 16, the transformation temperature of these shape memory alloys is from 75 ° C to
Since it is set to 110 ° C., when used in a room temperature environment, it can be used in the same state as ordinary screws, bolts and nuts. Further, when the screws, bolts and nuts are removed for dismantling the products, the products can be removed by merely placing the products in a high temperature environment without human intervention. Moreover, since the transformation temperature of the shape memory alloy is lower than the heat resistant temperature of the main plastics and rubbers, the plastics and rubbers are not melted and the product is not contaminated.

According to the third, tenth, or seventeenth aspect, the Ti-Ni alloy used as the shape memory alloy is excellent in corrosion resistance, wear resistance, and thermal cycle fatigue characteristics. Particularly effective as a bolt or nut.

Further, according to the structure of claim 4, 11 or 18, the transformation temperature of the Ti-Ni alloy is from 75 ° C to 100 ° C.
The temperature can be set to 0 ° C, which allows the product to be used in a room temperature environment and disassembled at a high temperature (75 ° C to 100 ° C).

Further, according to the structure of the fifth, twelfth or nineteenth aspect, a strong screw, bolt or nut having a large tensile strength can be produced by carrying out such an intermediate temperature treatment.

Further, according to the structure of the sixth, thirteenth or twentieth aspect, by performing such low temperature processing, it becomes easy to memorize and process a complicated shape such as a screw thread or a shape having a small curvature. .

According to the structure of claim 7, 14 or 21, Cu-Al-Ni used as the shape memory alloy.
Since the alloy or the Cu-Zn-Al alloy is lower in price than the Ti-Ni alloy and has good plastic workability, such special screws, bolts or nuts can be mass-produced at a lower cost.

On the other hand, according to the twenty-second or twenty-ninth aspect, the product can be assembled in a low temperature environment, and the screw head cross, one letter or hexagonal thread groove or hexagonal shape can be eliminated at room temperature. Therefore, the user does not accidentally loosen the screw or the bolt. It is also effective when you do not want to loosen the thing that has been tightened once. As a result, even if the loosening may cause a danger, or the performance or the function may be degraded, it is possible to avoid them.

According to the twenty-third or thirtieth aspect, the product is assembled in a low temperature environment, and the screw thread is deformed at room temperature, so that the assembly with the screw or the bolt becomes stronger. Therefore, it is difficult to remove the one that has been tightened once,
Prevents the user from accidentally loosening the screws or bolts or loosening them due to vibration or the like. As a result, even if the loosening may cause a danger, or the performance or the function may be degraded, it is possible to avoid them.

Further, according to the constitutions of claims 24 and 31, in a low temperature environment of zero degree or less, the product is assembled by using the screws and the bolts, and when the temperature is returned to the normal temperature, the shape memory state is restored. Prevent the screws and bolts from being removed or loosened.

According to the twenty-fifth or thirty-second aspect of the invention, the Ti-Ni alloy used as the shape memory alloy is excellent in corrosion resistance, wear resistance and thermal cycle fatigue characteristics, and therefore, screws, bolts or Especially effective as a nut.

Further, according to the structure of the twenty-sixth or thirty-third aspect, since the transformation temperature of the shape memory alloy can be set to 0 ° C. or lower and the shape memory alloy is in the practical composition range, such a screw or bolt can be realized. It will be possible.

Further, according to the twenty-seventh or thirty-fourth aspect, since the transformation temperature of the shape memory alloy can be set to a low temperature (zero degrees or less), it is possible to use the screw head or the screw thread at the normal temperature by the shape memory treatment. .

Further, according to the structure of claim 28 or 35, the Cu-Al-Ni alloy or the Cu-Zn-Al alloy used as the shape memory alloy is lower in price than the Ti-Ni alloy and has the plastic workability. Therefore, such special screws and bolts can be mass-produced at lower cost.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a screw or bolt according to a first embodiment of the present invention, FIG. 2 is a view showing its shape transition, FIG. 3 is a view showing screw processing by its rolling, and FIG. 4 is its use. FIG. 6 is a diagram for explaining the action of FIG. In the present invention,
The difference between the screw and the bolt is only whether or not the screw is engaged with the nut, and they are substantially the same in terms of configuration, action, and effect. Therefore, in the present embodiment, the screw and the bolt will be described together.

In FIG. 1, (a) shows the shape of the screw or bolt according to this embodiment at the time of shape memory processing, and (b) shows the shape of the screw or bolt when it is used. FIG.
The screw (or bolt) 1A at the time of shape memory processing of (a) is
It is composed of a circular screw head 11A and a rod-shaped male screw forming portion 12A in which a screw thread is not yet formed. Screw head 1
On the upper surface of 1A, a cross, a letter, or a hexagonal groove 13A into which the tip of the driver fits is formed. here,
The outer diameter d0 of the male screw forming portion 12A is formed to be smaller than the inner diameter of the female screw portion with which the screw is screwed, that is, the diameter of the screw thread of the female screw portion.

The screw (or bolt) 1B at the time of use in FIG. 1 (b) has a circular screw head 11B having a driver groove 13B formed on the upper surface, a screw thread 14B, and a screw groove 15B.
And a male screw portion 12B formed with. The screw head 11B and the male screw portion 12B have a shorter length (lateral direction) and a larger diameter than the corresponding portions in FIG. Also,
A thread 14 is formed on the male screw portion 12B by rolling described later.
B, a screw groove 15B is formed. Here, the outer diameter d and the valley diameter d1 of the male screw portion 12B are the same as those of the male screw portion 1
The size of 2B is set so that it can be screwed into the corresponding female media portion.

Next, the shape memory, plastic deformation, and state transition of the screw (or bolt) in the above-described embodiment will be described with reference to FIGS. 2 to 4. First, the shape memory alloy material to be the screw (or bolt) is shown in (a) of FIG.
It is processed into the shape of 1) or (a2) and stored in the shape. The material of (a1) is a simple rod-shaped body with no screw head formed, and the material of (a2) is the same as that shown in FIG. 1 (a) in which only the screw head 11A is formed. . At this stage, the male screw forming portion 12A, which is the male screw portion, has a simple rod shape, and its outer diameter d0 is smaller than the inner diameter of the female screw portion with which the screw (or bolt) is screwed.

As a shape memory processing method, for example, a shape memory alloy composed of a predetermined metal material in a predetermined ratio is used.
2 (a1) or (a) using a press molding machine or the like to sufficiently work and harden it by an appropriate cold working method such as rolling or wire drawing.
After molding into the shape of 2), it is fixed with an appropriate fixing jig so that the shape does not change during heat treatment, and heated and held at a temperature of 350 ° C to 500 ° C for several minutes to several hours. This is called medium temperature treatment, but other low temperature treatment or 800 ° C
There is a high temperature treatment in which a solution heat treatment is performed at ˜1000 ° C.

Next, by press working, pressure is applied in the axial direction of the screw, and as shown in FIG.
Increase the diameter of A. When there is no screw head as in (a1), the male screw forming portion 1 is formed at this stage using a press molding die or the like.
The diameter of 2A is increased and the screw head 13A is formed. The diameter d2 of the male screw forming portion 12A is formed to be substantially the same as the effective diameter of the final male screw portion.

Next, by thread rolling, as shown in FIG. 2C, a male screw portion 12B having a screw thread 14B and a screw groove 15B is formed. Rolling is a method in which a member to be processed is sandwiched between two flat plates or cylinders having a mold (there are three cylinders) and rolled while pressing to transfer the shape of the mold to the workpiece, This is a common production method for mass-produced screws and bolts. That is, screw rolling is
This is a method of forming male threads by forming threads and threads by plastic working.

Specifically, as shown in FIG. 3, a screw rolling having rolling dies 2a, 2b in which the male thread portion 12B of the product screw (or bolt) 1B has the same chevron shape and the same pitch as the male thread portion 12B is engraved. The manufacturing machine 2 is used. Rolling dies 2a, 2b
Between the male screw forming portion 1 of the screw material shown in FIG.
2A is sandwiched, and the rolling dies 2a and 2b are pressed against the surface and rolled. As a result, the portion of the rolling dies 2a, 2b pressed by the ridges becomes the valley of the screw, and the rolling dies 2a, 2b
The material rises to the valley of 2b and becomes a screw thread. In this way, the thread rolling is to form a screw without being cut like a normal cutting die, and as described above, the size of the diameter d2 of the male thread forming portion 12A before the rolling is set to the final male size. Although it is necessary to form the screw with a diameter substantially equal to the effective diameter, the material can be saved as compared with the cutting screw, and the tensile strength and the fatigue limit also increase.

In this way, screws and bolts made of shape memory alloy are manufactured. With these screws and bolts,
As shown in FIG. 4A, the component 3 is assembled to the product base 4 or the like. At this time, the screw 1B has the male screw portion 12
B is the female screw portion 4 of the base 4 through the mounting hole 3a of the component 3.
It is screwed into a and the driver is applied to the groove 13B of the screw head 11B and tightened. As a result, the component 3 becomes the base 4
Firmly fixed to.

When this product is to be decomposed for recycling or the like, it is placed in a temperature-controlled room or the like and placed in a high temperature environment. This temperature is set to a temperature higher than the transformation temperature of screws and bolts made of shape memory alloy.

As a result, the shape memory alloy screw or bolt returns to the shape memory processed shape as shown in (d1) and (d2) of FIG. 2, and as shown in FIG. The male screw portion 12B screwed to the female screw portion 4a on the upper part 4 returns to the original female screw forming portion 12A, so that it can be easily removed from the female screw portion 4a.

Therefore, it is possible to remove a large amount of shape memory alloy screws and bolts used in the product at one time and dismantle them. Moreover, if a plurality of products are put in the temperature-controlled room, a large amount of products can be disassembled at once.

Once the screws and bolts are returned to the shape memory state in a high temperature environment, the shape remains in the memory state even if the temperature is returned to normal temperature thereafter, so that the shapes of the screws and bolts are not obtained. Therefore, it is not necessary to maintain the high temperature environment until the removal of all the screws and bolts is completed, and the high temperature environment requires only a short time.

If the shape memory alloy is subjected to excessively large plastic deformation, the shape is not completely recovered (Ti-Ni alloy is 7.5%, Cu-Zn-Al alloy is 4%). Therefore, as shown in (a1) of FIG. 2, the one formed from a completely rod-shaped body is (a1) as shown in (d1) of the same figure.
The state is not completely returned to, and the screw head 11A remains slightly thick. However, when the male screw forming portion 12A is returned to its original position, the screws and bolts can be removed. Therefore, as shown in FIG. 4B, the diameter d0 of the male screw forming portion 12A may be appropriately smaller than the inner diameter d1 of the female screw portion 4a.

Specifically, when it is desired to make the screw equivalent to, for example, an M3 metric coarse screw, the inner diameter of the female screw portion is 2.5.
Since it is 59 mm, the male screw forming portion 12A at the time of shape memory
The diameter d0 is set to about 2.50 mm <d0 <2.55 mm. Even if it is impossible to completely restore the original state when the temperature is high, the male screw portion is easily detached from the female screw portion.

In addition, in order to return the shape memory alloy screw or bolt to its original shape in a high temperature environment, "force" is required to disengage from the corresponding female screw portion. When the shape memory alloy is Ti-49.8 at% Ni, it is 70 at 84 ° C.
A stress of 0 MPa = 71 Kgf / mm ² can be generated. This is a stress that can be sufficiently restored when the female screw portion is within the elastic deformation range and the friction coefficient between the male screw portion and the female screw portion is taken into consideration when tightening the screw.

Next, a second embodiment of the present invention is shown in FIGS. FIG. 5 is a side view of a nut according to a second embodiment of the present invention, FIG. 6 is a view showing its shape transition, FIG. 7 is a view showing its threading process, and FIG. 8 is a view showing its action during use. FIG.

In FIG. 5, (a) shows the shape of the nut according to the present embodiment during shape memory processing, and (b) shows the nut shape when used. The nut 5A at the time of shape memory processing of FIG. 5A has an inner surface 50A as a female screw forming portion.
It has a cylindrical shape having a hole 51A in which a thread groove is not yet formed. Here, the inner diameter of the nut 5A, that is, the diameter d2 of the hole 51A, is formed to be larger than the outer diameter of the male screw portion of the bolt screwed into the nut.

In addition, the nut 5B at the time of use of FIG. 5 (b)
Is formed into a hexagonal tube shape by plastic deformation by press processing described later, and a female screw portion 54B having a screw thread 52B and a screw groove 53B is formed in the hole 51B. Here, the root diameter d and the inner diameter d1 of the female screw portion 54B are
The size of the male screw portion corresponding to the female screw portion 54B is set to just fit.

Next, the shape memory, the plastic deformation, and the state transition of the nut in the above-described embodiment will be described with reference to FIGS. 6 to 8. First, the shape of the nut 5A at the time of shape memory processing is set to a cylindrical shape having a hole 51A as shown in FIG. 6A. After this is subjected to a shape memory process described later, a hexagonal nut 5B as shown in FIG. 6B is formed by plastic working using a hexagonal press die. This is, for example,
This is performed as shown in FIG. That is, first, FIG.
As shown in, the bolt 7 screwed into the nut is inserted into the hole 51A of the nut 5A in which the female screw portion is not formed yet, and the hexagonal press die 6 is set. Then, by pressing in the direction of the arrow, a nut 6B having a predetermined hexagonal shape is formed as shown in FIG. 7 (b). At this time,
The hole 51A also becomes smaller due to the compression, and the screw thread 7a and the screw groove 7b of the bolt 7 are transferred to the inner surface thereof. The root diameter d of the nut 5B thus formed is smaller than the inner diameter d2 of FIG. 6 (a).

Using this shape memory alloy nut 5B and the normal bolt 7 (the shape memory alloy bolt 1B described above is also acceptable), as shown in FIG. Etc.

When this product is to be disassembled for recycling or the like, the product is put in an atmosphere having a temperature higher than the transformation temperature of the shape memory alloy, as in the first embodiment. As a result, the nut 5B returns to the original shape memory state as shown in FIG. 6 (c). Therefore, as shown in FIG. 8B, the hole 51A of the nut 5A has a hole shape larger than the thread diameter of the bolt 7 and can be easily removed from the bolt 7. In this way, a large number of bolts and nuts can be removed and disassembled at once. Therefore, it has the same effect as the case of the screws and bolts, and has the effect that the amount of expensive shape memory alloy material is reduced.

In the first and second embodiments, a Ti-Ni alloy can be used as the shape memory alloy. This is because it is considered to be a practical alloy because it is easily stretched at high temperatures, is easy to work, and has excellent corrosion resistance, wear resistance, and thermal cycle fatigue properties. Deformed T
The transformation temperature at which the i-Ni alloy returns to its original shape is 75 ° C to 10 ° C.
0 ° C is good. This is usually the highest environmental temperature of the product at the time of packaging, and the temperature is usually 60 ° C to 65 ° C.
This is because the temperature is about ° C. Depending on the case, up to about 80 ℃,
When there is a possibility that the environmental temperature during use or packaging will rise, the transformation temperature of the shape memory alloy is raised accordingly.

The practical transformation temperature of the Ti--Ni alloy is about 1.
It is 0 ° C to 100 ° C. Considering that the plastic and rubber members are not melted, the transformation temperature as a shape memory alloy seems to be about 110 ° C. or lower. Ti-
The M transformation temperature of Ni alloy (which indicates the transformation temperature and extends to the martensite transformation temperature) largely depends on the alloy composition, and in order to set the transformation temperature to about 75 ° C. to 100 ° C., the composition is Ti-49.5 at% Ni to Ti-5
It must be in the range of 0.1 at% Ni. More preferably, Ti-49.7 at% Ni to Ti-50.0 at.
The range of% Ni is good. Even if the melting temperature of plastic or rubber is slightly lower than the transformation temperature of shape memory alloy, the transformation of screws, bolts and nuts in the high temperature environment of the product will be performed immediately, so immediately return to normal temperature. Thus, it is possible to prevent the influence of melting of plastic or rubber from occurring.

The heat treatment of the Ti--Ni alloy includes the above-mentioned medium temperature treatment, low temperature treatment and high temperature treatment, but the medium temperature treatment is preferable for the memory shape and transformation temperature of the above-mentioned embodiment. The low temperature treatment is carried out by heating the alloy to 800 ° C. or higher in advance to normalize the structure, forming it into a predetermined shape at room temperature, and
Memory processing is performed at a temperature of 0 to 300 ° C. This is suitable for storing a complicated shape or a curve having a small curvature.
In addition, the high temperature treatment is performed with a high N content of 50.5 at% or more.
Used for i alloy.

In the intermediate temperature treatment, as described above,
Although the memory treatment is performed at a temperature of 500 ° C., the lower the temperature, the larger the stress after heat treatment, and the higher the strength as a screw, bolt or nut. Therefore, 350 ℃ ~ 400 ℃
It is preferable to heat-treat (shape memory processing).

As another material for the shape memory alloys of the first and second embodiments, a Cu-Al-Ni alloy or a Cu-Zn-Al alloy can be used. These Cu-based alloys are inferior in corrosion resistance and wear resistance to Ti-Ni alloys, but are relatively inexpensive and have good plastic workability. Since the transformation temperature of these alloys varies greatly depending on the composition,
It is necessary to control the composition so that it transforms at an appropriate temperature (the Ti-Ni alloy is the same). These alloys are also Ti-Ni
Like alloys, it is easy to put into practical use.

As examples of other alloys, Ni-Al, Ag-
Cd, Au-Cd, Cu-Au-Zn, Cu-Sn, C
u-Zn, In-Tl, In-Cd, Ti-Ni-C
u, Ti-Ni-Fe, etc. are considered.

When the screw or bolt of the first embodiment or the nut of the second embodiment is used only at a low temperature such as below freezing point, the transformation temperature of the shape memory alloy should be set to around 0 ° C. As a result, the screws, bolts or nuts can be removed by simply leaving the product using the screws, bolts or nuts at room temperature, and the product can be disassembled easily. In this case, Ti-Ni
If it is an alloy, Ti-50.8 at% Ni to Ti-51
The range of at% Ni is good. With this composition, the transformation temperature can be set between about -10 ° C and 10 ° C.

Next, a third embodiment of the present invention will be described with reference to FIGS.
0 is shown. This is the second object of the present invention to prevent the screw or bolt once tightened from being loosened.

First, as shown in FIGS. 9A and 10A, a screw (or bolt) 20A is made of a shape memory alloy.
make. However, the heads 21A of the screws or bolts are in a state where there are no grooves such as a cross, a letter, and a hexagon, and the outer shape is not hexagonal. That is, the upper surface is in a circular shape with no tightening portion by a driver or a spanner. In this state, shape memory processing is performed. The transformation temperature of the screw or bolt is set to a low temperature of 0 ° C to -20 ° C or lower. After that, the screw or bolt head 21A is plastically deformed,
As shown in FIG. 9B, a cross, a letter or a hexagonal groove 22B is formed in the head 21B, or as shown in FIG. 10B, the head 21B has an external hexagonal shape. These have the same shapes as conventional screws and bolts.

Using this screw (or bolt) 20B,
Assemble the parts into the product in the low temperature environment. If this is left at room temperature, the groove 22B at the head of the screw (or bolt) 20B disappears due to transformation of the shape memory alloy, or the hexagonal shape returns to a circular shape. That is, a circular head 12A having a flat upper surface
It becomes extremely difficult to return to the screw (or bolt) 20 </ b> A having the above and loosen the tightened screw or bolt. As a result, it is possible to prevent loosening of the screw or bolt once tightened. When the use environment temperature of the product is below zero, the transformation temperature of the shape memory alloy is set to a temperature lower than that.

Next, a fourth embodiment of the present invention is shown in FIG. First, as shown in FIG. 11A, the shape of the screw (or bolt) 30A is made using a shape memory alloy. However, the shape of the thread 31A is slightly changed from the standard shape defined by JIS. For example, as shown by the solid line screw thread 31A enlarged in FIG. 11A, a screw thread having a nominal screw diameter of 0.5% is inflated. Therefore, it cannot be used as a screw or bolt as it is. This shape is made by slightly distorting the rolling mold from the standard. Shape memory processing is performed in the shape of the deformed screw (or bolt) 30A. This deformed screw (or bolt) 30A is re-rolled by a standard die to make a screw (or bolt) 30B having a standard thread 31B as shown in FIG. 11 (b). The product is assembled using the screw (or bolt) 30B.

If the transformation temperature of this shape memory alloy is set to 0 ° C. or lower and the product is assembled in an environment at a lower temperature than that, by leaving this product at room temperature, the shape memory alloy returns to the memory shape. Become. As a result, the screw or bolt and the female screw on the other side are tightened, and the screw or bolt can be attached more firmly.

According to this, it is more difficult to remove the screws and bolts than the third embodiment, and it is possible to prevent the screws and bolts once tightened from being removed at room temperature. If the operating temperature is below freezing, the transformation temperature of the memory alloy needs to be further lowered.

In the third and fourth embodiments, since the shape memory alloy returns to the memory state at the actual use temperature, it is preferable to set the transformation temperature of the shape memory alloy to -150 ° C to 0 ° C. Therefore, when a Ti-Ni alloy is used as the shape memory alloy, the composition range for setting the temperature range is Ti-50.9 at% Ni to Ti-, considering the practical range.
The range of 51.5 at% Ni is preferred. In addition, the practical range is Ti-49.5 at% Ni to Ti-51.5 at% N.
i.

To produce a Ti--Ni alloy having this composition range, after solution heat treatment at 800 ° C. to 1000 ° C.,
It is preferable to perform a high temperature treatment in which the quenched alloy is aged and heated at a temperature of about 400 ° C. for 1 hour or more. That is, high Ni
This is because it is suitable for alloy production.

[0077]

According to the first or eighth aspect of the present invention, the shape memory alloy is used for the screws and the bolts to assemble the respective parts and members into the product, so that the screws and the bolts are brought into the shape memory state. Back Each screw and bolt can be removed without human intervention simply by placing the product in an environment above the transformation temperature, so a large number of screws and bolts can be removed at one time, and the product can be disassembled. (Separation and separation) are facilitated, dismantling costs are reduced, and the recycling of parts and members is facilitated. It is also effective when it is desired to release the tightening with screws or bolts at a certain temperature, and for example, it can have a role as a switch for removing the screws or the bolts at a certain temperature. As a result, a person does not have to intervene to remove the screws and the bolts, so that the screws and the bolts can be removed or the switch can be turned on or off by remote control by temperature adjustment. Therefore, when there is a risk of danger, remote control is possible, which has the effect of avoiding danger.

According to the fifteenth aspect of the present invention, the shape memory alloy is used for the nut to assemble each part or member into the product, so that the nut is returned to the shape memory state. Since each nut can be removed without putting hands by simply placing the screw, it has the same effect as the case of the above-mentioned screws and bolts, and has the effect of requiring less expensive shape memory alloy material. .

Further, according to the invention of claim 2, 9 or 16, the transformation temperature of the shape memory alloy is 75 ° C to 110 ° C.
Since it is set to, when used in a room temperature environment, it can be used in the same state as ordinary screws, bolts and nuts. Further, when the screws, bolts and nuts are removed for dismantling the products, the products can be removed by merely placing the products in a high temperature environment without human intervention. Further, since the transformation temperature of the shape memory alloy is lower than the heat resistant temperature of the main plastics and rubbers, there is an effect that the plastics and rubbers are not melted and the product is not contaminated.

Further, according to the invention of claim 3, 10 or 17, the Ti-Ni alloy used as the shape memory alloy is excellent in corrosion resistance, wear resistance and thermal cycle fatigue characteristics. Particularly effective as a bolt or nut.

According to the invention of claim 4, 11 or 18, the transformation temperature of the Ti-Ni alloy is from 75 ° C to 100 ° C.
The temperature can be set to 0 ° C, which allows the product to be used in a room temperature environment and disassembled at a high temperature (75 ° C to 100 ° C).

According to the invention of claim 5, 12 or 19, by carrying out such an intermediate temperature treatment, a strong screw, bolt or nut having a large tensile strength can be produced.

According to the invention of claim 6, 13 or 20, such low temperature processing facilitates the memory processing of a complicated shape such as a screw thread or a shape having a small curvature. .

According to the invention of claim 7, 14 or 21, the Cu-Al-Ni used as the shape memory alloy is used.
Since the alloy or the Cu-Zn-Al alloy is lower in price than the Ti-Ni alloy and has good plastic workability, such special screws, bolts or nuts can be mass-produced at a lower cost.

On the other hand, according to the twenty-second or twenty-ninth aspect of the invention, the product can be assembled in a low temperature environment, and at the normal temperature, the screw head cross, a letter, a hexagonal thread groove, or a hexagonal shape can be eliminated. Therefore, the user does not accidentally loosen the screw or the bolt. It is also effective when you do not want to loosen the thing that has been tightened once. As a result, even if the loosening may cause a danger, or the performance or the function may be degraded, it is possible to avoid them.

According to the twenty-third or thirtieth aspect of the invention, the product is assembled in a low temperature environment, and the screw thread is deformed at room temperature, so that the assembly with the screw or the bolt becomes stronger. Therefore, it is difficult to remove the one that has been tightened once,
Prevents the user from accidentally loosening the screws or bolts or loosening them due to vibration or the like. As a result, even if the loosening may cause a danger, or the performance or the function may be degraded, it is possible to avoid them.

Further, according to the invention of claim 24 or 31, in a low temperature environment of zero degree or less, the product is assembled by using screws and bolts, and the temperature is returned to the shape memory state at room temperature. It is possible to prevent the screws and bolts from being removed or loosened.

According to the twenty-fifth and thirty-second aspects of the present invention, the Ti-Ni alloy used as the shape memory alloy is excellent in corrosion resistance, wear resistance, and thermal cycle fatigue characteristics, so that the screws, bolts or Especially effective as a nut.

Further, according to the invention of claim 26 or 33, such a screw or bolt can be realized because the transformation temperature of the shape memory alloy can be set to 0 ° C. or less and it is within the practical composition range of the shape memory alloy. It will be possible.

According to the twenty-seventh and thirty-fourth aspects of the present invention, since the transformation temperature of the shape memory alloy can be set to a low temperature (zero degrees or less), it can be used at room temperature by the shape memory treatment of the screw head and the screw thread. .

Further, according to the invention of claim 28 or 35, the Cu-Al-Ni alloy or Cu-Zn-Al alloy used as the shape memory alloy is lower in price than the Ti-Ni alloy and has plastic workability. Therefore, such special screws and bolts can be mass-produced at lower cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a shape memory processing shape of a screw or a bolt according to a first embodiment of the present invention and a shape when used.

FIG. 2 is a diagram showing a state transition of the first embodiment.

FIG. 3 is a diagram showing screw processing by rolling in the first embodiment.

FIG. 4 is an explanatory view showing an operation when using the first embodiment.

FIG. 5 is a view showing a shape memory processing shape of a nut according to a second embodiment of the present invention and a shape when in use.

FIG. 6 is a diagram showing a state transition of the second embodiment.

FIG. 7 is a diagram showing screw processing by a press in the second embodiment.

FIG. 8 is an explanatory view showing an operation when using the second embodiment.

FIG. 9 is a diagram showing a shape memory processed shape of a screw or a bolt according to the third embodiment of the present invention, a shape (groove) at low temperature, and a state transition thereof.

FIG. 10 is a diagram showing a shape-memory processed shape of a screw or a bolt according to the third embodiment of the present invention, a shape (hexagon) at low temperature, and a state transition thereof.

FIG. 11 is a diagram showing a shape memory processed shape of a screw or a bolt according to the fourth embodiment of the present invention, a shape at a low temperature, and a state transition thereof.

[Explanation of symbols]

1A, 1B, 20A, 20B, 30A, 30B Screw (or bolt) 2 Screw rolling machine 2a, 2b Rolling die 3 Parts 4 Base board 4a Female screw part 5A, 5B Nut 6 Press working type 7 Bolt 7a Screw thread 7b Screw Groove 8 Member 9 Housing 11A, 11B, 21A, 21B, 32A, 32B Screw head 12A Male screw forming portion 12B Male screw portion 13A, 13B, 22B Groove 14B, 31A, 31B Screw thread 15B Screw groove 50A Inner surface (forming female screw) Part) 51A, 51B screw hole 52B screw thread 53B screw groove 54B female screw part

Claims (35)

[Claims] 1. A screw made of a shape memory alloy, wherein an outer diameter of a male screw forming portion at the time of shape memory processing is formed smaller than an inner diameter of a female screw portion to which the formed male screw portion is screwed. A screw characterized in that a male screw portion that is screwed into the female screw portion is formed by plastic deformation. 2. The transformation temperature of the shape memory alloy is 75.degree.
The screw according to claim 1, wherein the screw is set to 0 ° C. 3. The screw according to claim 1, wherein the shape memory alloy is a Ti—Ni alloy. 4. The composition of the Ti—Ni alloy is Ti—49.
The screw according to claim 3, which is in a range of 5 at% Ni to Ti-50.1 at% Ni. 5. A Ti—Ni alloy is work-hardened by a cold working method and molded into a predetermined shape, and then 350 ° C.
5. The screw according to claim 3 or 4, wherein the screw is subjected to a medium temperature process of performing a memory process at a temperature of up to 500 ° C. 6. A low temperature in which a Ti—Ni alloy is preheated to 800 ° C. or higher to normalize its structure, molded into a predetermined shape at room temperature, and then subjected to a memory treatment at a temperature of 200 ° C. to 300 ° C. The screw according to claim 3 or 4, which has been subjected to a treatment. 7. The screw according to claim 1, wherein the shape memory alloy is a Cu—Al—Ni alloy or a Cu—Zn—Al alloy. 8. A bolt made of a shape memory alloy, wherein the outer diameter of the male screw forming portion at the time of shape memory treatment is smaller than the inner diameter of the nut side female screw portion to which the formed male screw portion is screwed. And a male screw portion that is screwed into the female screw portion on the nut side is formed by plastic deformation. 9. The transformation temperature of the shape memory alloy is 75 ° C. to 11 ° C.
The bolt according to claim 8, which is set at 0 ° C. 10. The bolt according to claim 8, wherein the shape memory alloy is a Ti—Ni alloy. 11. The composition of the Ti—Ni alloy is Ti-4.
The bolt according to claim 10, wherein the bolt has a range of 9.5 at% Ni to Ti-50.1 at% Ni. 12. The Ti—Ni alloy is worked and hardened by a cold working method to form a predetermined shape, and then 350
The bolt according to claim 10 or 11, wherein the bolt has been subjected to a medium temperature treatment for performing a memory treatment at a temperature of ℃ to 500 ℃. 13. A low temperature in which a Ti—Ni alloy is preheated to 800 ° C. or higher to normalize its structure, molded into a predetermined shape at room temperature, and then subjected to a memory treatment at a temperature of 200 ° C. to 300 ° C. The bolt according to claim 10 or 11, which has been treated. 14. The bolt according to claim 8, wherein the shape memory alloy is a Cu—Al—Ni alloy or a Cu—Zn—Al alloy. 15. A nut made of shape memory alloy, wherein the inner diameter of the female screw forming portion at the time of shape memory processing is formed larger than the outer diameter of the bolt side male screw portion screwed into the formed female screw portion. And a female thread portion to which the male thread portion on the bolt side is screwed is formed by plastic deformation. 16. The transformation temperature of the shape memory alloy is 75.degree.
The nut according to claim 15, wherein the nut is set to 10 ° C. 17. The nut according to claim 15, wherein the shape memory alloy is a Ti—Ni alloy. 18. The composition of the Ti—Ni alloy is Ti-4.
18. The nut according to claim 17, which is in a range of 9.5 at% Ni to Ti-50.1 at% Ni. 19. A Ti—Ni alloy is work-hardened by a cold working method and molded into a predetermined shape, and then 350
The nut according to claim 17 or 18, which has been subjected to a medium-temperature treatment for performing a memory treatment at a temperature of ℃ to 500 ℃. 20. A low temperature in which a Ti—Ni alloy is preheated to 800 ° C. or higher to normalize its structure, molded into a predetermined shape at room temperature, and then subjected to a memory treatment at a temperature of 200 ° C. to 300 ° C. The nut according to claim 17 or 18, which has been treated. 21. The nut according to claim 15, wherein the shape memory alloy is a Cu—Al—Ni alloy or a Cu—Zn—Al alloy. 22. A screw made of a shape memory alloy, characterized in that the screw head is formed by plastic deformation after shape-memory treatment in a state where the screw head has no tightening portion formed thereon. screw. 23. A screw made of a shape memory alloy, which is formed by subjecting a thread shape to a shape memory treatment in a distorted state from a standardized shape, and then plastically deforming to the standardized shape. Characterized by screws. 24. The transformation temperature of the shape memory alloy is -150.degree.
24. The screw according to claim 22 or 23, wherein the screw is set to ˜0 ° C. 25. The screw according to claim 22 or 23, wherein the shape memory alloy is a Ti—Ni alloy. 26. The composition of the Ti—Ni alloy is Ti-5.
26. The screw according to claim 25, which is in a range of 0.9 at% Ni to Ti-51.5 at% Ni. 27. The Ti—Ni alloy has a temperature of 800 ° C. to 100 ° C.
27. The screw according to claim 25 or 26, wherein after the solution heat treatment at 0 ° C, the rapidly cooled alloy is subjected to a high temperature treatment of aging heating at a temperature of about 400 ° C for 1 hour or more. 28. The screw according to claim 22, wherein the shape memory alloy is a Cu—Al—Ni alloy or a Cu—Zn—Al alloy. 29. A bolt made of a shape memory alloy, wherein the tightening portion is formed on the screw head by plastic deformation after the shape memory treatment is performed in a state where the tightening portion is not formed on the screw head. bolt. 30. A bolt made of a shape memory alloy, which is formed by subjecting a thread shape to a shape memory treatment in a distorted state from a standardized shape, and then plastically deforming to the standardized shape. Bolt characterized by. 31. The transformation temperature of the shape memory alloy is -150.degree.
31. The bolt according to claim 29 or 30, wherein the bolt is set to ˜0 ° C. 32. The bolt according to claim 29 or 30, wherein the shape memory alloy is a Ti—Ni alloy. 33. The composition of the Ti--Ni alloy is Ti-50.
33. The bolt according to claim 32, wherein the bolt has a range of 9 at% Ni to Ti-51.5 at% Ni. 34. The Ti—Ni alloy is 800 ° C. to 100 ° C.
34. The bolt according to claim 32 or 33, wherein after the solution heat treatment at 0 ° C, the rapidly cooled alloy is subjected to a high temperature treatment of aging heating at a temperature of about 400 ° C for 1 hour or more. 35. The bolt according to claim 30, wherein the shape memory alloy is a Cu—Al—Ni alloy or a Cu—Zn—Al alloy.