Plug for rotary friction welding and rotary friction welding equipment using plug

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a plug used for rotary friction welding that enables miniaturization of the device, and a rotary friction welding device using the plug.

【0002】

[Conventional technology]

Most of the parts used in the members of the nuclear power plant are made of stainless steel in consideration of harsh operating conditions. SUS304 material was mainly used.

【0003】

However, when this material is heated and melted by welding or the like, the vicinity of the heat-affected zone becomes sensitive and the structure becomes unstable, which causes cracks to occur over a long period of time.

【0004】

For this reason, in nuclear power plants, there is an urgent need to develop preventive maintenance and repair technologies for such cracks, and active research and development is being carried out in cooperation with manufacturers.

【0005】

As a preventive maintenance technique, a method has been proposed in which a sensitized structure is restored to a state close to the original state by heating the heat-affected zone of the material to be repaired by using thermal energy such as laser light.

【0006】

On the other hand, as a repair technique for cases where microcracks have already occurred on the surface, the microcracks are repaired by melting the surface using thermal energy such as laser light, and at the same time, the sensitized structure is close to the original state. The technology to return to is proposed.

【0007】

However, if a relatively large crack occurs and the crack progresses to the inside and cannot be repaired simply by melting the surface, the defective part is deleted and a new member is inserted there for repair. Repair techniques such as the taper plug rotary friction welding method have been proposed (for example, JP-A-11-281790).

【0008】

This taper plug rotary friction welding method will be described with reference to FIGS. 12 and 13. First, as shown in FIG. 12A, the defective portion of the material to be repaired, in which cracks and the like have occurred, is deleted by cutting, drilling, or the like to form the tapered hole 32. In the figure, number 31 indicates the material to be repaired.

【0009】

Then, the grip portion 33b of the plug 33 shown in FIGS. 12 (b) and 12 (c) is attached to a chuck (not shown), and the truncated cone-shaped tapered plug portion 33a is inserted into the tapered hole 32 (see FIG. 13). ). Note that FIG. 12 (b) is a side view of the plug 33, and FIG. 12 (c) is a top view of the plug 33 as viewed from the direction of arrow AA.

【0010】

A motor (not shown) is connected to the chuck to rotate the plug 33 at several thousand revolutions / minute. Further, a hydraulic device (not shown) is used so that a predetermined force is applied to the tapered plug portion 33a in the axial direction when the plug 33 is rotationally pressure-welded.

【0011】

As a result, the taper plug portion 33a rotates while rubbing against the taper hole 32, and the surface of both the taper plug portion 33a and the taper hole 32 is melted and welded by the rotational friction heat at that time.

【0012】

[Problems to be Solved by the Invention]

However, in the above configuration, as will be described later, there are problems that the device becomes large and the operability is poor.

【0013】

That is, the surfaces are melted by frictional heat in order to weld the taper hole 32 and the taper plug portion 33a, but when the taper plug portion 33a is inserted into the taper hole 32, all of these surfaces come into contact with each other at the same time. A large friction torque works, and it is necessary to use a high-power motor that rotates the plug 33 while overcoming this.

【0014】

However, since these repair works must be performed in a limited space such as in a nuclear reactor, there are cases where a work space cannot be secured with a large-scale device.

【0015】

Further, when the repair work must be performed in a special atmosphere (for example, underwater), it may be difficult to pressurize by the hydraulic device.

【0016】

Furthermore, in the repair inside the reactor, since the worker cannot enter the reactor, all the work must be performed by remote control, but the operability is very poor with the conventional equipment, especially. When the grip portion 33b is mounted on the chuck, since the grip portion 33b is formed in a cylindrical shape, the plug 33 slips due to a large friction torque unless the chuck is firmly tightened, and the rotational torque of the motor is transmitted. In some cases, there was a problem that the torque could not be achieved.

【0017】

Therefore, an object of the present invention is to provide a plug used for rotary friction welding, which enables miniaturization of the device and improvement of operability, and a rotary friction welding device using the plug.

【0018】

[Means for solving problems]

In order to solve the above problems, the invention according to claim 1 is a grip portion to be gripped by a chuck to which rotational force and pressing force are applied, and a repaired portion formed by removing defective portions such as cracks by drilling or the like. It is provided with a tapered plug portion that is inserted into the tapered hole of the material and is rotationally welded by the rotational force and pressing force from the chuck, and is welded to the tapered hole by the frictional heat generated at that time to fill the tapered hole. In the plug, the tapered plug portion is formed in a conical trapezoidal shape, and the conical angle is set to an angle smaller than the angle formed by the tapered hole so that the friction torque during rotational friction welding can be reduced. It is characterized by.

【0019】

The invention according to claim 2 is that when the angle formed by the tapered hole is set to 20 to 60 degrees, the cone angle of the tapered plug portion is set to be 0 to 5 degrees smaller than the angle formed by the tapered hole. It is characterized by.

【0020】

The invention according to claim 3 is characterized in that a member having a melting point lower than that of the material forming the tapered plug portion is adhered to the pressure-welded surface of the tapered plug portion.

【0021】

The invention according to claim 4 is characterized in that a powder of the same material as the material forming the tapered plug portion is sprayed onto the pressure-welded surface of the tapered plug portion.

【0022】

The invention according to claim 5 is characterized in that a groove having a predetermined shape is formed on the pressure contact surface of the tapered plug portion.

【0023】

The invention according to claim 6 is characterized in that the groove has a shape of any one of a rectangular groove, a mountain valley groove, a valley groove, a mountain groove, and a corrugated groove.

【0024】

The invention according to claim 7 is characterized in that the chuck hole for gripping the grip portion of the chuck is formed in a rectangular columnar shape, and the grip portion is formed corresponding to the rectangular columnar shape.

【0025】

8. The present invention is characterized in that when the plug is pressed into the tapered hole, it is pressed by the force of air or a spring.

【0026】

BEST MODE FOR CARRYING OUT THE INVENTION

The first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing in detail the plug 2 and the tapered hole 3 in the tapered plug rotary friction welding device according to the present invention. Number 4 in the figure indicates the material to be repaired.

【0027】

The schematic configuration of the taper plug rotary friction welding device according to this embodiment is the same as the conventional one, but the conical angle of the taper plug portion 2a of the trapezoidal conical plug 2 is set to be smaller than the angle formed by the taper hole 3. It is characterized by the fact that it is.

【0028】

That is, the conical angle α of the taper plug portion 2a is set smaller than the angle β formed by the taper hole 3 (α <β).

【0029】

FIG. 2 is a diagram when the taper plug portion 2a is inserted into the taper hole 3 with such a configuration. As can be seen from FIG. 2, since the conical angle α of the taper plug portion 2a and the angle β formed by the taper hole 3 have an angular relationship as described above, the state where the taper plug portion 2a is inserted into the taper hole 3 Then, only the tip portion is in contact.

【0030】

Therefore, when the plug 2 is rotated in such a state, the friction torque generated is only the one generated from the contact portion of the tip portion, and the plug 2 can be rotated even by a motor having a small output.

【0031】

Further, since the contact area is small, it is not necessary to pressurize the plug 2 with a large force, and a device for generating a large force such as a hydraulic device is not required as a pressurizing device.

【0032】

Then, when the contact portion is melted by friction, the plug 2 is pushed into the tapered hole 3 according to the amount of melting, and the contact area gradually increases.

【0033】

At this time, since the newly melted portion is preheated by the heat of the already melted portion, the new portion can be easily melted, and the friction torque can be significantly reduced.

【0034】

From various experiments, the angle β formed by the taper hole 3 is preferably 20 to 60 degrees, and the conical angle α of the taper plug portion 2a at that time is set to an angle smaller than the angle β in the range of 0 to 5 degrees. It is preferable to do so.

【0035】

Next, a second embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0036】

In the above-described embodiment, the conical angle α of the taper plug portion 2a is set appropriately smaller than the angle β formed by the taper hole 3 to significantly reduce the friction torque.

【0037】

On the other hand, in the present embodiment, the welding start temperature is lowered by further adhering a member having a melting point lower than that of the material of the tapered plug portion 2a to the tapered plug portion 2a while satisfying such an angular relationship. The friction torque is reduced.

【0038】

FIG. 3 is a diagram showing a cross section of the plug 2 when the adherend member 5 is adhered to the taper plug portion 2a.

【0039】

Gold, silver brazing, etc. can be exemplified as such an adherend member 5, and plating methods such as electroplating and hot dip galvanizing can be exemplified as an adherence method, but the present invention is not limited thereto, and the taper plug is not limited thereto. Any member and method may be used as long as the melting point is lower than that of the portion 2a and the adherend member 5 can be adhered to the taper plug portion 2a with a thin film.

【0040】

Normally, the taper plug portion 2a is formed of the same material as the member 4 to be repaired, and when the member 4 to be repaired is stainless steel, the melting point of gold is about 500 ° C lower than that of this stainless steel, and the thermal conductivity is increased. Since the rate is extremely high, the friction torque can be significantly reduced.

【0041】

Further, since silver wax has a lower melting point and is cheaper than gold, it is possible to significantly reduce the friction torque while reducing the repair cost.

【0042】

Next, a third embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0043】

In the second embodiment described above, in order to significantly reduce the friction torque, a case where an adherend member 5 such as gold or silver wax is adhered to the taper plug portion 2a by plating or the like has been described. .. In this case, the surface of the adherend member 5 that has been adhered is smoothed by a method such as plating.

【0044】

However, as can be seen from the gist described in the first embodiment, if the area where the taper plug portion 2a is in contact with the taper hole 3 is small, the friction torque for causing welding from that portion first becomes small.

【0045】

Therefore, in the present embodiment, the surface of the tapered plug portion 2a is sprayed with a metal powder of the same material as the tapered plug portion 2a to be adhered.

【0046】

According to this method, the metal powder sprayed on the taper plug portion 2a is adhered in a state of having irregularities, so that the contact area between the taper plug portion 2a and the taper hole 3 becomes small, and the friction torque becomes large. It is possible to reduce the torque.

【0047】

The adherend member 5 is not limited to the metal powder of the same material as the taper plug portion 2a, and other members such as silver brazing and gold can also be used.

【0048】

Next, a fourth embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0049】

In each of the embodiments described so far, the cone angle α of the taper plug portion 2a is made smaller than the angle β formed by the taper hole 3, or the surface of the taper plug portion 2a is made of a metal powder of the same material as the taper plug portion 2a. The friction torque was reduced by reducing the contact area between the taper plug portion 2a and the taper hole 3.

【0050】

On the other hand, in the present embodiment, various grooves 8 (8a to 8e) are formed on the surface of the tapered plug portion 2a to reduce the contact area between the tapered plug portion 2a and the tapered hole 3. Is.

【0051】

As the shape of such a groove 8, the shapes shown in FIGS. 4 to 8 can be proposed. FIG. 4 shows a rectangular groove 8a, FIG. 5 shows a mountain valley groove 8b, FIG. 6 shows a valley groove 8c, FIG. 7 shows a chevron groove 8d, and FIG. 8 shows a corrugated groove 8e.

【0052】

When a rectangular groove 8a is used as the groove 8, the width thereof should be such that the contact surface area between the taper plug portion 2a and the taper hole 3 is about 50%, and the depth should be such that the groove 8 does not remain when welded. It is preferably about 0.5 mm.

【0053】

Further, when the mountain valley groove 8b is used as the groove 8, the contact area is extremely small, so that the shape is effective for reducing the friction torque, and the width and depth thereof are preferably about 1 mm in pitch and 0.5 mm in depth.

【0054】

When the valley groove 8c, the chevron groove 8d, and the corrugated groove 8e are used as the groove 8, the width and depth thereof are preferably about 1 mm in pitch and 0.5 mm in depth.

【0055】

By forming the groove 8 having such a shape, the contact surface between the tapered plug portion 2a and the tapered hole 3 can be made small, so that the friction torque can be significantly reduced.

【0056】

Next, a fifth embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0057】

In the second and third embodiments, gold, silver wax, and metal powder are adhered to the surface of the tapered plug portion 2a, and in the fourth embodiment, grooves of various shapes 8 are formed on the surface of the tapered plug portion 2a. Was formed to reduce the friction torque.

【0058】

On the other hand, in the present embodiment, as shown in FIG. 9, these are combined to reduce the friction torque.

【0059】

Looking at the welding process in terms of time, there are generally a region RA where the initial torque acts as shown in FIG. 10 to start welding, and a region RB where the entire welding is performed after experiencing the maximum torque.

【0060】

In FIG. 10, the curve 13 shows the measured value of the friction torque curve when the plug 33 of the conventional configuration shown in FIGS. 13 and 12 is used, the curve 14 shows the measured value of the friction torque curve when gold-plated, and the curve 15 shows the rectangular groove 8a. When formed, the curve 16 shows the measured value of the friction torque curve of the configuration according to the present invention when the metal powder is exposed.

【0061】

As can be seen from this figure, the configuration most effective in reducing the initial torque and the configuration most effective in reducing the maximum torque are not necessarily the same structure.

【0062】

That is, from FIG. 10, the most effective way to reduce the initial torque is the configuration in which the rectangular groove 8a is formed (curve 15), and the initial torque can be reduced by about 20% as compared with the conventional configuration. In addition, the most effective way to reduce the maximum torque is the configuration in which metal powder is sprayed (curve 16), and the maximum torque can be reduced by about 8%.

【0063】

In this way, there are effective configurations for each in the welding process, and by forming the rectangular groove 8a as illustrated in FIG. 9 and spraying the metal powder, the initial torque and the maximum torque can be reduced. It will be possible to work together.

【0064】

Of course, depending on the size of the groove 8 and the surface condition of the adherend member 5 to be adhered, and the angle difference between the tapered plug portion 2a and the tapered hole 3, the configuration effective for reducing the initial torque and the maximum torque can be reduced. Since the effective configurations change, it is meaningless to specify them uniquely, but at least when the configurations effective for reducing the initial torque and the configurations effective for reducing the maximum torque are different, these configurations are used. The combined use is effective for significantly reducing the friction torque as a whole.

【0065】

Next, a sixth embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0066】

In each of the embodiments described so far, the configuration for reducing the friction torque has been described in order to reduce the size of the device, but the present embodiment relates to the configuration for facilitating the repair work.

【0067】

As shown in FIGS. 13 and 12, since the grip portion 33b of the plug 33 having the conventional configuration is formed in a columnar shape, the chuck is firmly tightened, and at that time, the central axis of the plug 33 is set to the central axis of the chuck. If the plugs are not tightened together, the plug 33 may slip due to the friction torque.

【0068】

In particular, when such a taper plug rotary friction welding device is used for repairing the inside of a nuclear reactor or the like, it is necessary to remotely control the work, but at that time, the work of attaching the plug 33 to the chuck is also performed by remote control. There was a problem that it had to be done and it was very difficult to sufficiently tighten the chuck.

【0069】

Therefore, in the present embodiment, as shown in FIG. 11, the grip portion 2b is formed into a rectangular pillar and the chuck hole (not shown) of the chuck 1 is also formed into the same shape, and the grip portion 2b is inserted into the chuck hole. It is configured so that it can be installed just by itself. Note that FIG. 11A shows a top view of the plug 2, and FIG. 11B shows a side view thereof.

【0070】

With such a configuration, it is not necessary to align the central axis of the plug 2 with the central axis of the chuck, and it is not necessary to firmly tighten the chuck. Rotational friction welding can be performed without causing slippage, which greatly improves operability.

【0071】

Next, a seventh embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same configurations as those of the above-described embodiments, and the description thereof will be omitted.

【0072】

In the case of the plug 33 having the conventional configuration shown in FIGS. 13 and 12, a large friction torque is generated because the welded surfaces come into contact with each other at one time, and therefore a large force is required to pressurize the plug 33 in the direction of the tapered hole 32. The hydraulic system was used.

【0073】

However, when repairing by rotary friction welding in a nuclear reactor or the like, the repaired part may be underwater, and it is difficult to pressurize the plug 2 by the hydraulic device in such an atmosphere.

【0074】

However, by using the plug 2 described so far, the friction torque can be significantly reduced, so that the pressing force can be reduced correspondingly. For example, in an air pressurizing device or a spring pressurizing device using high pressure air or a spring. It becomes possible to use such a device.

【0075】

These devices are smaller than the hydraulic system, and there is a risk of oil leakage in the case of the hydraulic system, but in the case of the air pressurizing device and the spring pressurizing device, there is no need to worry about this, so reliability is eliminated. Will be improved and the work will be easier.

【0076】

[Effect of the invention]

As described above, according to the present invention, the tapered plug portion is formed into a truncated cone shape, and the cone angle is set to an angle smaller than the angle formed by the tapered hole. Therefore, the friction torque at the time of rotational friction welding is increased. This can be reduced, which improves the miniaturization and operability of the device.

[Simple explanation of drawings]

[Figure 1]

It is a figure which shows the structure of the plug and the taper hole which apply to the description of the 1st Embodiment of this invention.

[Figure 2]

It is sectional drawing which shows the situation when the plug is inserted into a taper hole.

[Fig. 3]

It is a figure which shows the structure of the plug applied to the description of the 2nd and 3rd Embodiment of this invention.

[Fig. 4]

It is a figure which shows the structure of the plug applied to the description of the 4th Embodiment of this invention, and is the side view at the time of forming a rectangular groove.

[Fig. 5]

It is a figure which shows the structure of a plug, and is the side view at the time of forming a mountain valley-shaped groove.

[Fig. 6]

It is a figure which shows the structure of a plug, and is the side view at the time of forming a valley groove.

[Fig. 7]

It is a figure which shows the structure of a plug, and is the side view at the time of forming a chevron groove.

[Fig. 8]

It is a figure which shows the structure of a plug, and is the side view at the time of forming a corrugated groove.

[Fig. 9]

It is a figure which shows the structure of the plug applied to the description of the 5th Embodiment of this invention, and is the cross-sectional view when the rectangular groove and the adherend member are formed.

[Fig. 10]

It is a figure which shows the measured value of the friction torque curve with respect to the structure of various taper plug portions.

[Fig. 11]

It is a figure which shows the structure of the plug applied to the description of the 6th Embodiment of this invention.

[Fig. 12]

It is a figure which shows the structure of the plug and the taper hole which apply to the description of the prior art.

[Fig. 13]

It is sectional drawing which shows the situation when the plug is inserted into a taper hole.

[Explanation of symbols]

1 chuck 2 plug 2a Taper plug part 2b grip 3 Tapered hole 4 Material to be repaired 5 Adhesive member 8 grooves 8a rectangular groove 8b Sanya-shaped groove 8c valley groove 8d Yamagata groove 8e corrugated groove