JP6787764B2 - Friction stir welding tool - Google Patents

Description

The present invention relates to a friction stir welding tool.

In recent years, friction stir welding has been used as a material joining method (see Patent Document 1).
In friction stir welding, a rotating joining tool is pressed against the object to be welded, and the object to be welded is fluidized and joined by frictional heat.
In friction stir welding, the joining tool is mounted on the spindle of the friction stir welding device and is rotationally driven around a rotation axis in the direction intersecting the surface of the object to be joined. Then, it is moved along the joint portion on the surface of the object to be joined in the rotating state.

In the friction stir welding device, a dedicated device is often used in order to obtain frictional heat by applying pressure by axial movement (movement of the tool or movement of the work) while rotating the joining tool with high torque. On the other hand, if it is the rotation of the spindle, the movement of the tool, or the movement of the work, a general-purpose machine tool can be used as a substitute.
As the joining tool, for example, a tool in which a conical pin coaxially downward is formed on the lower end surface of a columnar tool body is used. A stepped shoulder is formed around the pin.
During the friction stir welding operation, the pins are press-fitted into the workpiece and the shoulder is maintained facing the surface of the workpiece. Then, the friction portion becomes hot due to the friction between the rotating pin and the object to be joined, and the object to be joined is agitated and joined.

Japanese Unexamined Patent Publication No. 2005-177844

As described above, in friction stir welding, the temperature of the joint becomes high as the joint operation occurs, and heat is conducted to the spindle of the machine tool via the joint tool.
In the dedicated friction stir welding device, the heat from the joining tool is treated. However, general-purpose machine tools do not assume a situation in which heat is conducted to the spindle or spindle head and becomes high temperature only within the range of normal cutting.
For this reason, when a joining tool is attached to a general-purpose machine tool and friction stir welding is performed, the heat conducted to the spindle may adversely affect the spindle or bearings and other mechanical parts that support the spindle. .. For example, there are concerns about damage to the main bearing of the spindle head, damage to the retainer portion, runout of the rotating axis due to thermal expansion, and fretting damage at the tapered shank portion.

An object of the present invention is to provide a friction stir welding tool capable of suppressing heat conduction to a spindle of a machine tool.

The friction stir welding tool of the present invention is a friction stir welding tool mounted on a spindle of a machine tool, and is attached to a shank portion connected to the spindle, a chuck portion connected to the shank portion, and the chuck portion. It has a connecting tool for friction stir welding, and is characterized in that a cooling jacket is formed on the peripheral surface of the chuck portion, and a refrigerant passage for passing a refrigerant is formed in the cooling jacket. ..

In the present invention, by supplying a refrigerant such as air or coolant to the refrigerant passage, the refrigerant passes through the cooling jacket, and the chuck portion can be cooled when the refrigerant passes through the cooling jacket. Therefore, even if the temperature of the joining tool becomes high due to the operation of friction stir welding, the heat is cooled by the chuck portion, and heat conduction to the shank portion or the spindle can be suppressed.

In the friction stir welding tool of the present invention, it is desirable that the refrigerant passage is connected to a center hole formed in the shank portion, and the refrigerant is center-through air or center-through coolant of the spindle.

In the present invention, the refrigerant can be supplied through the spindle, the entire tool can be rotated together with the spindle, and the structure can be simplified. Further, since the center-through air or the center-through coolant generally provided in the spindle of the machine tool is used as the refrigerant, it is not necessary to prepare a special refrigerant supply device.
When the center hole of the shank is not used, as a device for supplying the refrigerant from the outside to the rotating tool, a fixing portion connected to the spindle head such as a refrigerant supply to the through tool tool is provided to receive the refrigerant. It is desirable to separately provide a configuration for delivering the refrigerant to the rotating shank portion and chuck portion.

In the friction stir welding tool of the present invention, it is desirable that a heat insulating portion is interposed between the shank portion and the chuck portion.
In the present invention, even if there is heat conduction from the joining tool to the chuck portion, heat can be blocked by the heat insulating portion, and heat conduction to the shank portion or the spindle can be suppressed.
As the heat insulating portion, a connecting member formed of a heat insulating material, a heat insulating structure in which the contact area of the joint portion is reduced, and the like can also be used.

In the friction stir welding tool of the present invention, it is desirable that a recess for preventing contact is formed on the surface of the chuck portion in contact with the joining tool or the surface of the joining tool in contact with the chuck portion.
In the present invention, since the contact area is formed to be small by the recesses between the joining tool and the chuck portion, heat conduction from the joining tool to the chuck portion can be suppressed.
The concave portion is preferably a concave portion that leaves a cross-shaped convex portion on the end surface of the joining tool or the bottom surface of the chuck portion.

In the friction stir welding tool of the present invention, it is desirable that the shank portion has a recess for preventing contact formed on the surface of the tapered portion that comes into contact with the main shaft.
In the present invention, even if there is heat conduction to the shank portion, the contact area is formed to be small by the recesses, so that heat conduction to the main shaft can be suppressed.
As the concave portion, it is effective to form it in the intermediate thickness portion of the tapered portion, and the configuration is such that the large diameter ring portion and the small diameter ring portion come into contact with the main shaft at two locations (between the large diameter ring portion and the small diameter ring portion). Is a recess), or a configuration in which only the large-diameter ring portion is in contact with the spindle (all other than the large-diameter ring portion is a recess).

In the friction stir welding tool of the present invention, it is desirable that a temperature marker whose appearance changes according to the temperature of the chuck portion is installed on the peripheral surface of the chuck portion.
In the present invention, the temperature of the chuck portion during operation can be monitored by the temperature marker, and the influence on the spindle can be avoided by visually checking the overheated state or the like.
As the temperature marker, it is preferable that the color and brightness of the entire surface change according to the temperature. If the appearance of the entire surface changes in this way, it can be identified from the outside even in the rotating state. The display by numbers and letters is not preferable as a temperature marker because it cannot be read in a rotating state. However, if it is displayed by the number and thickness of striped patterns that are continuous in the rotation direction, it can be identified even in the rotation state.

According to the present invention, it is possible to provide a friction stir welding tool capable of suppressing heat conduction to a spindle of a machine tool.

Sectional drawing which shows one Embodiment of this invention. An enlarged cross-sectional view showing the cooling jacket and the refrigerant passage of the embodiment. FIG. 2 is a cross-sectional view showing a shank portion of the embodiment. The perspective view which shows the temperature marker of the said embodiment. The perspective view which shows the temperature marker of a rotating state. Sectional drawing which shows the shank part of another embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIGS. 1 and 2, the friction stir welding tool 1 of the present embodiment is mounted on a spindle 8 of a machine tool to perform friction stir welding of an object to be joined 7.

As the machine tool of the present embodiment, various types capable of rotating the spindle 8 and moving the spindle 8 relative to the work (the object to be welded 7 in the present embodiment but the object to be machined when used as a machine tool) are used. The spindle 8 and the friction stir welding tool 1 can be moved to any position with respect to the object to be joined 7.
In a machine tool, the spindle 8 is rotatably supported by the spindle head of the machine tool and is rotationally driven by a motor installed in the spindle head.

The friction stir welding tool 1 has a shank portion 20 connected to the spindle 8, a chuck portion 30 connected to the shank portion 20, and a friction stir welding joining tool 10 connected to the chuck portion 30.
A heat insulating portion 40 is interposed between the shank portion 20 and the chuck portion 30. A cooling jacket 50 is formed on the peripheral surface of the chuck portion 30. The cooling jacket 50 is formed with a refrigerant passage 60 for supplying a refrigerant.
Further, a temperature marker 70 whose appearance changes according to the temperature of the chuck portion 30 is installed on the peripheral surface of the chuck portion 30.

The joining tool 10 is a tool for friction stir welding, and has a shoulder 12 and a pin 13 at the tip of the tool body 11.
When the joining tool 10 is press-fitted into the object to be joined 7 in a rotating state, the pin 13 at the tip is press-fitted into the object to be joined 7 while heating and melting the material of the object to be joined 7, and the seam of the object to be joined 7 is joined. Can be melt-bonded.

The shank portion 20 is a 7/24 taper shank (BT type) for automatic tool replacement defined in JISB6339-2: 2011, and can be attached to and detached from the spindle 8 based on JISB6340-2: 2011 corresponding to the same standard.
The shank portion 20 has a tapered cone 21 (tapered portion) corresponding to the conical chuck hole 81 of the main shaft 8.

In the tapered cone 21, a recess 22 is formed in the middle portion of the peripheral surface in the direction of the rotation axis, a small diameter ring portion 23 is formed on the small diameter side of the recess 22, and a large diameter ring portion 24 is formed on the large diameter side of the recess 22. ing.
The small-diameter ring portion 23 and the large-diameter ring portion 24 are formed as a portion where the surface is left by forming a recess 22 with respect to the original surface of the tapered cone 21, and become convex with respect to the recess 22. There is.

When the shank portion 20 is mounted on the spindle 8, the recess 22 does not come into contact with the inner peripheral surface of the chuck hole, and only the small diameter ring portion 23 and the large diameter ring portion 24 come into close contact with the chuck hole. As a result, the area where the shank portion 20 and the spindle 8 are in close contact with each other is reduced to about a fraction of the case where the entire tapered cone 21 is in close contact with the chuck hole without the recess 22, and heat conduction in the portion is reduced. It is suppressed.
The small-diameter ring portion 23 and the large-diameter ring portion 24 that are in close contact with the chuck holes have an area, an outer diameter, and an axial width that can sufficiently transmit the necessary torque when performing friction stir welding with the joining tool 10. ..

The chuck portion 30 is a tubular member having a holding hole 31 into which the tool body 11 can be inserted, and fixing screws 32 are screwed into the side surfaces from two directions.
By tightening the fixing screw 32 with the tool body 11 inserted, the tool body 11 is fixed inside the holding hole 31, whereby the joining tool 10 has the same rotation shaft as the chuck portion 30 or the shank portion 20. It is held on the line.

The heat insulating portion 40 is a cylindrical member interposed between the shank portion 20 and the chuck portion 30, and is fixed to each of them.
The heat insulating portion 40 is formed of a low heat conductive material such as ceramics, and even if the chuck portion 30 becomes hot due to the heat from the joining tool 10, the heat conduction to the shank portion 20 can be significantly reduced or blocked.
The bolt 42 that connects the heat insulating portion 40 and the shank portion 20 and the bolt 43 that connects the heat insulating portion 40 and the chuck portion 30 are independent of each other, and are in the heat conduction path between the shank portion 20 and the chuck portion 30. It is configured so that a low thermal conductive material always intervenes.
A center hole 41 is formed in the heat insulating portion 40, and the center hole 41 is communicated with the center hole 25 of the shank portion 20.

The joining tool 10 has a chuck portion 30 between the fixing screw 32 and the peripheral surface of the tool body 11, and the peripheral surface of the tool body 11 on the opposite side of the fixing screw 32 and the inner peripheral surface of the holding hole 31. Contact with.
The contact between the fixing screw 32 and the inner peripheral surface of the holding hole 31 is sufficiently smaller than the total area of the peripheral surface of the tool body 11, and heat conduction from the joining tool 10 can be suppressed.
The bottom surface of the holding hole 31 of the chuck portion 30 is opened, and the bottom surface of the joining tool 10 is received by contacting with the heat insulating portion 40.

In the joining tool 10, a “+” -shaped notch 14 is formed as a recess for preventing contact on the end surface of the tool body 11, and four fan-shaped convex portions 15 are formed. By bringing the convex portion 15 into contact with the heat insulating portion 40 which is the bottom surface of the holding hole 31, heat conduction is suppressed even in the contact portion between the end surface of the tool body 11 and the heat insulating portion 40.
The central portion of the notch 14 of the tool body 11 is communicated with the center hole 41 of the heat insulating portion 40, and is communicated with the center hole 25 of the shank portion 20 via the center hole 41. The notch 14 reaches the outer peripheral surface of the tool body 11, and the notch 14 communicates with the gap between the outer peripheral surface of the tool body 11 and the inner peripheral surface of the holding hole 31.

The cooling jacket 50 has a case member 51 that covers the outer peripheral surface of the chuck portion 30, and a guide member 52 housed inside the case member 51.
The end of the case member 51 on the joining tool 10 side is arranged at an intermediate position on the peripheral surface of the chuck portion 30, and the end on the opposite side is connected to the heat insulating portion 40.
A large number of heat radiation fins 53 are formed on the outer peripheral surface of the case member 51.

The guide member 52 is installed inside the case member 51, and the space formed inside is divided into an introduction portion 61 and a discharge portion 62. A spiral concave groove is formed on the outer peripheral surface of the guide member 52, and a spiral passage 63 is formed between the guide member 52 and the inner peripheral surface of the case member 51. One end of the spiral passage 63 is communicated with the introduction portion 61, and the other end is communicated with the discharge portion 62.

The refrigerant passage 60 includes an introduction portion 61, a discharge portion 62, and a spiral passage 63 formed in the cooling jacket 50.
The introduction portion 61 is communicated with the holding hole 31 through a through hole 64 penetrating the front and back of the chuck portion 30, and the holding hole 31 passes through the notch 14 of the joining tool 10 and the center hole 41 of the heat insulating portion 40 to form a shank portion. It is communicated with the center hall 25 of 20.
The discharge unit 62 is open to the outside through the discharge hole 65.

The center hole 25 of the shank portion 20 communicates with the center hole 82 of the spindle 8 when it is mounted on the spindle 8.
In this state, when center-through air or center-through coolant is supplied as the refrigerant from the spindle 8, these are introduced into the refrigerant passage 60 through the center holes 82, 25, 41.

In FIG. 2 , the refrigerant C introduced from the center hole 25 of the shank portion 20 is guided to the outer periphery of the tool body 11 through the radial notch 14, and is guided to the outer peripheral surface of the chuck portion 30 (one step outside the holding hole 31). It is introduced into the through hole 64 through the gap between the expanded portion). The refrigerant C introduced into the through hole 64 passes through the gap between the guide member 52 and the chuck portion 30 and is introduced into the introduction portion 61.
The refrigerant C introduced into the introduction section 61 passes through the spiral passage 63 over a predetermined time, cools the chuck section 30 during that time, reaches the discharge section 62, and is discharged from the discharge hole 65.

The temperature marker 70 is installed on the outer peripheral surface of the chuck portion 30 near the joining tool 10.
As shown in FIG. 4 , the temperature marker 70 is a plate-shaped display panel, and is fixed to the chuck portion 30 by screwing or the like.
The temperature marker 70 is obtained by applying or printing a temperature-sensitive material whose color and brightness change with temperature on the surface of the panel, and when the temperature of the chuck portion 30 rises due to the heat from the joining tool 10, the color and brightness are changed. By changing the brightness, the temperature rise can be visually recognized from the outside.

Since the temperature marker 70 changes the color and brightness of the entire panel, it can be visually recognized from the outside even when the chuck portion 30 is in a rotating state.
As shown in FIG. 5 , when the chuck portion 30 is rotating, the temperature marker 70 moves at a high speed, so that it is visually recognized as a strip-shaped movement locus 71 continuous in the circumferential direction.
At this time, for example, if the display of the temperature marker 70 is a character or the like, it is difficult to read it. However, since the temperature marker 70 changes in color and lightness, it can be easily visually recognized as a change in color and lightness of the movement locus 71.

In the present embodiment, the friction stir welding tool 1 is attached to the machine tool by connecting the shank portion 20 to the spindle 8. Then, the spindle 8 and the friction stir welding tool 1 are moved by the machine tool so that the joining tool 10 faces the object to be joined 7. By rotating the spindle 8 in this state, the shank portion 20, the chuck portion 30, and the joining tool 10 are integrally rotationally driven. Then, by press-fitting the joining tool 10 into the object to be joined 7, friction stir welding can be performed.

Here, in the joining tool 10, the temperature becomes high due to friction with the object to be joined 7, and the heat from the joining tool 10 is conducted to the chuck portion 30.
However, the contact area between the joining tool 10 and the chuck portion 30 is limited to a small size by the notch 14 (recessed portion for preventing contact) and the convex portion 15, and heat conduction from the joining tool 10 is suppressed. can do.
Further, a cooling jacket 50 and a refrigerant passage 60 are installed in the chuck portion 30, and even if there is heat conduction from the joining tool 10, it can be cooled.

Further, a heat insulating portion 40 is interposed between the chuck portion 30 and the shank portion 20, and even if there is heat conduction from the joining tool 10, this can be restricted or blocked.
Further, even between the shank portion 20 and the main shaft 8, the mutual contact area is limited to be small by the recess 22, and the heat conduction conduction from the joining tool 10 can be suppressed.
As described above, even if high heat is generated in the joining tool 10 due to friction stir welding, it is possible to prevent the heat from being conducted to the spindle 8 via the chuck portion 30 and the shank portion 20.

In cooling by the refrigerant passage 60, center-through air or center-through coolant may be used properly depending on the processing stage.
For example, during the processing operation of friction stir welding, center through air is passed through the refrigerant passage 60, and the chuck portion 30 is cooled by this air. The air that has passed through is dissipated into the atmosphere.
When the processing is completed, the center through coolant is passed through the refrigerant passage 60 instead of air, and the chuck portion 30 is cooled by this coolant. The passed coolant flows down from the cooling jacket 50, is received by the coolant recovery path installed in the machine tool, and is recovered in the coolant tank.
By properly using the coolant in this way, it is possible to prevent the coolant from adhering to the object to be joined 7 due to air during processing. Further, after processing, cooling can be performed in a short time with a coolant. If a coolant cooling device is installed in the coolant recovery path or the coolant tank, cooling after processing can be completed in a shorter time.

The present invention is not limited to the above-described embodiment, and modifications within the range in which the object of the present invention can be achieved are included in the present invention.
As the joining tool 10, existing parts can be used as they are. Even if it is an existing part, a notch 14 can be provided at the end thereof to form a convex portion 15.
The range of the recess 22 in the shank portion 20 may be appropriately designed for implementation. As described above, in the small diameter ring portion 23 and the large diameter ring portion 24 that are in close contact with the chuck hole, the area, outer diameter, and axial width that can sufficiently transmit the torque required for friction stir welding with the joining tool 10 are large. It suffices if it can be secured.

It is not essential that both the small diameter ring portion 23 and the large diameter ring portion 24 are formed in the shank portion 20.
In FIG. 6 , the tapered cone 21 of the shank portion 20A is formed with a recess 22 up to the end of the small diameter, and only the large diameter ring portion 24 on the large diameter side is provided.
In the shank portion 20A, only the large-diameter ring portion 24 contacts the spindle 8, but if the axial length of the rotation center of the large-diameter ring portion 24 is a predetermined length, the axial direction can also be regulated correctly.
Further, reducing the contact area of the shank portion 20 by the recess 22 is not essential to the present invention and may be omitted as appropriate.

The heat insulating portion 40 is not limited to a solid member using a low friction material, and may be hollowed out or used in combination with other heat insulating means.
Further, the heat insulating portion 40 is not essential to the present invention and may be omitted.
The configuration of the cooling jacket 50 and the refrigerant passage 60 is not limited to the configuration of the above-described embodiment. For example, the heat radiation fin 53 for air cooling may be omitted as appropriate.

It is not essential to use the spiral passage 63 as the refrigerant passage 60. However, by circulating the refrigerant in a spiral shape, the passage time of the refrigerant can be lengthened and the cooling effect of the refrigerant can be enhanced.
The guide member 52 is not essential, and the inside of the cooling jacket 50 may be simply a cavity.
The refrigerant passed through the refrigerant passage 60 does not have to be the center through air supplied from the spindle 8 or the center through coolant, and the configuration introduced from the center holes 82, 25, 41 of each part is not essential.

The present invention relates to a friction stir welding tool and can be used for friction stir welding using a general-purpose machine tool.

1 ... Friction stir welding tool, 10 ... Joining tool, 11 ... Tool body, 12 ... Colder, 13 ... Pin, 14 ... Notch, 15 ... Convex part, 20, 20A ... Shank part, 21 ... Tapered cone, 22 ... Concave part, 23 ... Small diameter ring part, 24 ... Large diameter ring part, 25 ... Center hole, 30 ... Chuck part, 31 ... Holding hole, 32 ... Fixing screw, 40 ... Insulation part, 41 ... Center hole, 42, 43 ... Bolt, 50 ... Cooling jacket, 51 ... Case member, 52 ... Guide member, 53 ... Radiation fin, 60 ... Refrigerant passage, 61 ... Introduction part, 62 ... Discharge part, 63 ... Spiral passage, 64 ... Through hole, 65 ... Discharge hole, 7 ... Joint, 70 ... Temperature marker, 71 ... Movement locus, 8 ... Spindle, 81 ... Chuck hole, 82 ... Center hole.

Claims (5)

A friction stir welding tool mounted on the spindle of a machine tool.
It has a shank portion connected to the spindle, a chuck portion connected to the shank portion, and a joining tool for friction stir welding connected to the chuck portion.
A cooling jacket is formed on the peripheral surface of the chuck portion, and a refrigerant passage through which the refrigerant passes is formed in the cooling jacket.
Between the shank portion and the chuck portion is friction stir welding tool you, characterized in that the heat insulating portion is interposed. A friction stir welding tool mounted on the spindle of a machine tool.
It has a shank portion connected to the spindle, a chuck portion connected to the shank portion, and a joining tool for friction stir welding connected to the chuck portion.
A cooling jacket is formed on the peripheral surface of the chuck portion, and a refrigerant passage through which the refrigerant passes is formed in the cooling jacket.
The surface of the chuck portion or surface of the welding tool in contact with the chuck portion, the friction stir welding tool you, characterized in that the recess for preventing contact is formed, in contact with the welding tool. A friction stir welding tool mounted on the spindle of a machine tool.
It has a shank portion connected to the spindle, a chuck portion connected to the shank portion, and a joining tool for friction stir welding connected to the chuck portion.
A cooling jacket is formed on the peripheral surface of the chuck portion, and a refrigerant passage through which the refrigerant passes is formed in the cooling jacket.
Said shank portion, the surface of the tapered portion in contact with the spindle, friction stir welding tool you, characterized in that the recess for preventing contact is formed. A friction stir welding tool mounted on the spindle of a machine tool.
It has a shank portion connected to the spindle, a chuck portion connected to the shank portion, and a joining tool for friction stir welding connected to the chuck portion.
A cooling jacket is formed on the peripheral surface of the chuck portion, and a refrigerant passage through which the refrigerant passes is formed in the cooling jacket.
Wherein the circumferential surface of the chuck portion, the friction stir welding tool you, characterized in that the temperature marker appearance changes according to the temperature of the chuck portion is provided. Any one of claims 1 to 4, wherein the refrigerant passage is connected to a center hole formed in the shank portion, and the refrigerant is center-through air or center-through coolant of the spindle. Friction stir welding tool described in.

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