JP2009262166A - Friction stud welding device and its suction pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction pad and the like by which a friction stud welding device can be fixed on the surface of a workpiece with high suction force and frictional force. <P>SOLUTION: The suction pad 10 is a means for fixing, on the surface of a workpiece, a friction stud welding device which joins a stud bolt to the surface of a workpiece by a friction stud welding method. In the front portion to be oppositely arranged on the workpiece surface, an air intake hole 17 is provided to be connected to a vacuum pump and, in the periphery, an airtight material 14 is installed that hermetically seals between the front portion and the workpiece, with a non-slip member 15 mounted also on the periphery separately from the airtight material 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a friction stud joining apparatus for joining a stud bolt (joined article) to the surface of a workpiece (joined article) by a friction stud joining method, and a suction pad for fixing the apparatus to the surface of the workpiece. It is.

  There is an arc stud method as a conventional method for joining a joined object to an object to be joined. In the arc stud method, first, an arc discharge is generated between a joined article and a workpiece, and the joined article and the article to be joined are melted by the arc discharge, and a molten product is formed between the joined article and the article to be joined. A molten pool is formed. Next, the bonded object is pressed against the object to be bonded in a state where the molten pool is formed, and the bonded object is bonded to the object to be bonded.

  There is a friction welding method as another method for joining a joined object to an object to be joined. In the friction welding method, the bonded object is rotated in a state in which the bonded object is pressed against the object to be bonded, and frictional heat is generated between the bonded object and the object to be bonded, and the joint between the bonded object and the object to be bonded is plastic. A joined object and a to-be-joined object are joined by producing a deformation | transformation (for example, refer patent document 1).

There is brazing as another conventional method for joining a joined object to an object to be joined. In brazing, a brazing material having a melting point lower than that of the bonded object and the object to be bonded is disposed between the bonded object and the object to be bonded, and the brazing material is melted to bond the bonded object and the object to be bonded ( For example, see Patent Document 2).
Japanese Patent Laid-Open No. 2002-153979 JP 2002-290068 A

  However, the arc stud method has a problem that defects such as cracks and blowholes occur in the process of solidifying the molten pool, the quality of the welded portion and the bonding strength are likely to vary greatly, and the bonding reliability is low. In addition, in order to perform the arc stud method, an auxiliary device such as a gun for performing welding, a welding power source for applying voltage and a device for supplying a shielding gas for preventing oxidation, etc., and wiring of these auxiliary devices And piping is necessary. Moreover, the oxide film removal process before joining, a stud joining process, and a ferrule removal process are required, and there are many processes.

  The friction welding method is a stable method that is not affected by a change in posture, but in order to cause plastic deformation, it is necessary to press the bonded product against the workpiece with a pressing force of several hundred kg to ton order. Therefore, the friction welding method can be applied only to the joint that can withstand such a pressing force and the workpiece to be joined. There is a problem that it cannot be joined by the law. The generated frictional heat is proportional to the product of the relative speed and the pressing force. When the joint has a small diameter, the relative speed is low, and thus a particularly large pressing force or ultra-high speed rotation is required.

  In the brazing of aluminum, there is a problem that a step of removing the oxide film on the portion to which the brazing material of the bonded article and the object to be bonded adheres is required, and the number of processes is increased. Moreover, it is difficult to apply brazing to high-strength aluminum alloys having a wide melting temperature range and a relatively small difference in melting point with the brazing material, such as Cu, Mg, Zn, and Si. .

In order to solve these problems, the present inventors have disclosed a friction stud joining method capable of joining a stud bolt to an object to be joined (hereinafter referred to as a workpiece) with a small pressing force without deteriorating the working environment, and the same. Developed a joining device using This joining apparatus has the structure shown in FIG. 1 and is used as shown in FIG. That is, the suction pad 10 is provided in the front part of the joining apparatus 1, and the suction pad 10 is fixed to the surface of the work B, and the stud bolt A is pressed while rotating and joined onto the work B. When the stud bolt A is pressed, a eutectic material that is a melting point lowering substance is inserted between the stud B and the workpiece B to promote local melting.
This joining device can be effectively used when, for example, a stud bolt for fixing a heat insulating panel is attached to an LNG tank containing liquefied natural gas (abbreviated as LNG).

In FIG. 1, the friction stud joining device 1 presses the stud bolt A against the surface of the work B (see FIG. 2) and rotates the stud bolt A to generate frictional heat, thereby causing the stud bolt A to be applied to the work. Join. For example, the stud bolt A is joined so that the axis is perpendicular to the outer surface of the spherical LNG tank. The joining apparatus 1 includes a gripping part 5 that grips a stud bolt A and extends toward the rear (upper part in the drawing), an air cylinder 3 that displaces the gripping part 5 back and forth (up and down in FIG. 1), and the gripping part 5. And a control means (not shown) for controlling the driving of the air cylinder 3 and the spindle motor 2. Reference numeral 4 in the figure denotes an operation handle.
Further, as shown in FIGS. 1B and 1C, the suction pad 10 provided at the front portion is integrally fastened to the main body of the joining apparatus 1 with bolts 12 and faces the surface of the workpiece. An intake hole 17 is provided in the front portion, and an airtight material 14 made of hard rubber is attached to the entire inner and outer peripheries surrounding the intake hole 17. The suction pad 10 is overlapped with the front part facing the surface of the work, and the air in the space sealed between the airtight members 14 (between the front part and the work) is discharged from the suction hole 17, whereby the suction pad 10. 10 is adsorbed to the work surface and fixed. By doing so, even if the work (for example, the tank wall surface) is a non-magnetic material and can only be accessed from one side, the work place is narrow, and it is difficult to use a robot or the like, the joining device 1 can be made smooth. Can be used.

However, this joining apparatus has the following problems. That is, (1) When the stud bolt is joined, the reaction force in the pressing direction and the suction force cancel each other and the vertical stress is lowered, so that the frictional force between the workpiece and the suction pad is lowered, and the joining device The whole may rotate. (2) With the exhaustion of the airtight material, the thickness thereof decreases, so that the metal portion of the suction pad main body may come into contact with the workpiece or the suction force / friction force may be reduced. (3) If dust, dust, etc. adhering to the surface of the workpiece, or burrs generated during joining adhere to the airtight material, the friction coefficient tends to decrease. (4) When a malfunction occurs in the middle of the exhaust path, such as when the exhaust path is long, there is a possibility that the adsorbing force decreases and the fixing state of the joining device to the workpiece becomes unstable.
The present invention has been made to solve these problems, and provides a preferable suction pad that provides a high suction force and friction force to a workpiece, and a friction stud joining device including the same.

The suction pad of the friction stud joining device according to the present invention is for fixing a joining device for joining a stud bolt to the surface of the workpiece by the friction stud joining method, and is arranged opposite to the workpiece surface. In addition to providing an air inlet hole connected to the vacuum pump in the front part and providing an airtight material that seals between the front part and the workpiece around the front part, a non-slip member is provided on the front part separately from the airtight material. It is characterized by being attached to.
Note that the friction stud joining device may be integrally connected to the suction pad as described later, but the device may be detachable and attached to the suction pad one by one. .

  In the suction pad of the present invention, the suction hole and the airtight material are provided on the front surface portion opposed to the surface of the workpiece as described above, and the anti-slip member is provided separately from the airtight material. Rather than having both the airtight material and the non-slip member as a common member, both are configured independently to obtain the maximum effect with the optimal material for maintaining airtightness and generating frictional force. Can do. That is, a) the non-slip member can be made relatively hard (for example, hard rubber) and the airtight material can be made soft, and therefore the adhesion performance of the airtight material can be improved and the adsorption force to the workpiece can be improved. B) As a non-slip member, one with high frictional force generation effect can be adopted, and the use stability of the joining device can be improved without increasing the suction area (size of the suction pad). Is possible.

The suction pad of the present invention is preferably provided with a plurality of suction areas in the front portion, and the suction holes and the airtight material are provided in each suction area.
By doing so, for example, even if an airtight leak occurs in any of the suction areas, the airtightness is maintained in the other suction areas, and the state where the suction pads are fixed to the workpiece is maintained. Immediate fixing does not become unstable.

In the suction pad of the present invention, the surface (front surface) of the anti-slip member is preferably formed on a curved surface or an inclined surface that follows the work surface.
When the surface of the workpiece is curved, such as when a stud bolt is joined to the outer wall of a spherical tank, the surface of the anti-slip member is formed as a curved surface or an inclined surface as described above so that it follows the surface of the workpiece. This is advantageous in terms of the ease with which a frictional force is generated. A plurality of non-slip members having different surface shapes corresponding to the curved surface of the workpiece surface are prepared, and the anti-slip member may be used by appropriately replacing the front surface portion of the suction pad. Although the front surface portion of the suction pad may be a curved surface that follows the workpiece surface, it requires considerable cost to prepare a large number of suction pads corresponding to the workpiece. Further, since the airtight material can be soft as described above, it is not necessary to make its surface curved or the like.

For the suction pad of the invention, it is preferable that the airtight material is formed of a sponge made of rubber or synthetic resin having closed cells.
A sponge made of rubber or synthetic resin is soft and easily deformed, and has closed cells inside, so that it is suitable for securing airtightness. That is, when the air in the front portion of the suction pad is exhausted from the intake hole with a vacuum pump or the like, the airtight material made of the sponge is compressed between the front portion of the suction pad and the work and deforms to both while deforming. It follows and adheres closely, bringing high airtightness between the two to ensure the suction performance of the suction pad. Since the hermetic material is easily deformable, it is advantageous in that the anti-slip member is pressed against the work surface to obtain a high frictional force.

In the suction pad of the invention, it is more preferable to provide a dust seal for protecting the airtight material on the side closer to the stud bolt insertion position than the airtight material.
In the friction stud joining method, as described above, the stud bolt to be rotated is pressed against the surface of the work to generate frictional heat, and both are joined using the frictional heat. At this time, a burr | flash generate | occur | produces from the front-end | tip of a stud bolt, and the surface of a workpiece | work, and there exists a possibility that the part may adhere to an airtight material. When burrs adhere to the airtight material, the suction force decreases, and as a result, the friction coefficient of the suction pad decreases. By providing a dust seal on the side closer to the stud bolt insertion position on the inner side than the airtight material as described above, it is possible to avoid adhesion of burrs to the airtight material, and to prevent the adsorption force and friction force from being reduced. Can do.

The friction stud joining device according to the present invention is characterized in that a suction pad having any one of the above-described configurations is integrally provided at a front portion.
In such a joining apparatus, when the stud bolt is joined to the workpiece surface, the operator can easily attract and fix the joining apparatus at an arbitrary place by the action of the suction pad, and the pressing direction and the rotating direction during joining can be fixed. Suction force and frictional force that can withstand the reaction force can be stably generated. Even if the workpiece is, for example, a non-magnetic outer wall of an LNG tank, the same adsorption force / friction force can be obtained, so that the stud bolt can always be easily joined. In addition, since equipment such as the suction means for the suction pad can be installed at a remote location, it is possible to reduce the equipment brought into the work place.

In the suction pad of the present invention, the anti-slip member is provided on the front surface portion in addition to the airtight material, so that it is possible to obtain the maximum effect with the optimum materials for the airtight maintenance and the generation of the frictional force, respectively. It can be securely fixed to the surface.
By using a plurality of suction areas, it is possible to stabilize the state where the bonding apparatus is fixed to the workpiece surface.
If the surface of the anti-slip member is formed on a curved surface or an inclined surface that follows the workpiece surface, it is easy to generate a strong frictional force, and the stability of the joining apparatus in use can be further enhanced.
Forming the airtight material with a rubber or synthetic resin sponge having closed cells is particularly advantageous in that the suction performance of the suction pad to the workpiece is ensured and a high frictional force is obtained.
If a dust seal for protecting the airtight material is provided on the side closer to the stud bolt insertion position than the airtight material, it is possible to avoid sticking to the airtight material, which tends to occur when the stud bolt is joined. And decrease in frictional force can be prevented.

  According to the friction stud joining device of the invention, since a high adsorption force and friction force on the workpiece can be obtained, the operation of joining the stud bolt to the workpiece surface can be easily performed.

  An embodiment of the invention will be described with reference to FIGS. FIG. 2 is a schematic view showing a state in which the friction stud joining device 1 is fixed to the workpiece surface. FIGS. 3A and 3B show an example of an embodiment relating to the suction pad 10 (particularly, the pad main body 11) fixed to the front portion of the bonding apparatus 10, wherein FIG. 3A is a front sectional view, and FIG. It is. 4A and 4B show another embodiment relating to the suction pad 10, wherein FIG. 4A is a bottom view of the suction pad 10 formed in a square shape, and FIG. 4B is a bottom view of the suction pad 10 formed in a circle shape. is there. FIG. 5 is a conceptual diagram showing an embodiment of the exhaust structure of the suction pad 10, and FIG. 6 is a conceptual diagram showing another embodiment of the exhaust structure of the suction pad 10.

  As shown in FIG. 2, the suction pad 10 attached integrally with the friction stud joining device 1 has a stud pressing direction reaction force (straight dashed arrow) generated when the stud bolt A is pressed against the work B, and a stud. A stud rotating direction reaction force (circular broken arrow) is generated when the bolt A is rotated. Therefore, the suction pad 10 needs to be configured to be able to generate the suction force and the friction force against the pressing direction reaction force and the rotation direction reaction force.

  As shown in FIGS. 3A and 3B, the suction pad 10 is sufficient for the stud bolt A (see FIG. 1) to pass through the center of a square or circular pad body 11 made of an aluminum alloy. An insertion port 13 having a large size is provided. Further, an airtight material 14, a non-slip member 15 and a dust seal 16 are attached to a surface (front surface portion, lower side in FIG. 3) where the pad main body 11 faces the surface of the workpiece B (see FIG. 2). Then, air is discharged from the suction hole 17 provided so as to penetrate the pad main body 11 in the thickness direction by an exhaust means such as a vacuum pump 21 (see FIGS. 1 and 5) connected thereto, thereby obtaining a suction pad. 10 is adsorbed on the surface of the workpiece B, and the bonding apparatus 1 is fixed to the surface of the workpiece B via the adsorption pad 10.

  The airtight member 14 is disposed as a continuous body surrounding the intake hole 17 and seals between the front portion and the work B. A soft rubber sponge or a synthetic resin sponge is used as the airtight material 14, and the inside thereof has closed cells. Since the sponge is soft and easily deformed, when the suction pad 10 is brought close to the surface of the work B and air is exhausted from the suction hole 17 by the vacuum pump 21, the airtight material 14 is compressed by the work B and the pad main body 11. And the gap between the surface of the workpiece B and the pad main body 11 is sealed all around.

  The anti-slip member 15 shown in FIG. 3 is made of hard rubber, and for example, chloroprene synthetic rubber or natural hard rubber is used. The anti-slip member 15 generates a frictional force against the rotational reaction force generated when the joining device 1 rotates the stud bolt A, and faces the front surface portion of the suction pad 10, that is, the surface of the workpiece B. Provided on the entire periphery of the. In addition, when a stud bolt is joined to the outer surface of a spherical tank or the like, it is preferable that the surface of the anti-slip member 15 adheres to the outer surface with as wide an area as possible.

  The dust seal 16 is provided to protect the airtight material 14. The dust seal 16 is attached to the inner peripheral surface of the insertion hole 13 of the stud bolt A, which is closer to the center than the airtight material 14 in the pad main body 11. In the friction stud joining method, the rotated stud bolt A is pressed against the surface of the work B to generate frictional heat, and both are joined using the frictional heat. At this time, if a burr is generated between the tip of the stud bolt A and the surface of the workpiece B and a part thereof adheres to the airtight material 4, the airtightness may be reduced and the friction coefficient may be reduced. In order to prevent this, a soft rubber dust seal 16 is attached to the suction pad 10 of FIG.

  In the suction pad 10 of FIG. 4A, the front surface portion of the pad main body 11 is divided into four in the vertical and horizontal directions to form a four-part suction area 18. Each suction area 18 is provided with an intake hole 17 and an airtight material 14 surrounding the entire periphery of the intake hole 17. In addition, although the anti-slip | skid member 15 and the dust seal | sticker 16 are also attached to the same front surface part, illustration is abbreviate | omitted for easy understanding. The anti-slip member 15 may be attached in an arbitrary suction area 18. Further, the dust seal 16 is disposed at a location closer to the center than the airtight members 14 such as the periphery of the insertion opening 13.

In the example of FIG. 4B, the front surface portion of the suction pad 10 is divided into a concentric circle and a two-part suction area 18 is configured. Each suction area 18 is provided with an intake hole 17 and an airtight material 14 surrounding the entire periphery of the intake hole 17. Note that the anti-slip member 15 and the dust seal 6 are not shown in the same manner as described above.
In this manner, when a plurality of suction areas 18 are provided, even if any one of the suction areas 18 is damaged in the airtight material 14 and the degree of vacuum is reduced (airtight leakage or the like), the other suction areas 18 Since the joining device can be fixed by the action, the fixing of the joining device 1 to the surface of the workpiece B does not immediately become unstable.

  As shown in FIG. 5, the suction pad 10 discharges air from the front surface portion opposed to the surface of the workpiece B, so that the normal exhaust path 20 and the normal exhaust path 20 have the above-described problems. And an emergency exhaust path 30 for performing emergency exhaust from the front portion. The normal exhaust path 20 has one end connected to the suction hole 17 of the suction pad 10 and the other end connected to a vacuum pump 21 installed at a predetermined distance from the bonding apparatus 1. . The suction hole 17 and the vacuum pump 21 are connected by a flexible pressure-resistant air hose or the like, and the length of the hose can be extended to about 40 m. An ejector may be used in place of the vacuum pump 21.

  The emergency exhaust path 30 is a means for performing emergency exhaust from the front portion of the suction pad 10 when there is a malfunction in the normal exhaust path 20. The other end is connected to the hole 17, and is connected to a reserve tank 31 and a compressor 32 that are installed at a predetermined distance from the joining device 1. The intake hole 17 and the reserve tank 31 are connected by a flexible pressure-resistant air hose or the like, and the length of the hose can be extended to about 40 m. A connection fitting that can be branched into two systems is attached to the intake hole 17, and the normal exhaust path 20 and the emergency exhaust path 30 may be connected to the connection port, respectively.

  The suction pad 10 is provided with detection means for detecting the degree of vacuum in the space between the front portion and the surface of the work B on which the front portion is disposed. For example, a digital vacuum gauge may be connected to the intake port of the vacuum pump 21 as the detection means. When the degree of vacuum in the suction pad 10 decreases, the joining of the stud bolt A by the joining device 1 (that is, rotation / pressing of the stud bolt A) is immediately stopped by the control means (not shown).

  When the joining of the stud bolt A by the joining device 1 is stopped, the control means immediately exhausts air from the front portion of the suction pad 10 through the emergency exhaust path 30. In the emergency exhaust, the compressed air from the compressor 32 moves the piston in the reserve tank 31, thereby discharging the air from the front portion. At that time, the air urgently exhausted from the front portion is stored in the reserve tank 31.

  An air blow path is also connected to the suction hole 17 of the suction pad 10 for air blowing from the front portion toward the surface of the workpiece B when the front portion is brought close to the surface of the workpiece B. If the air blow is performed in this manner before the connection device 1 is fixed to the surface of the workpiece B, dust, dust and the like on the surface can be removed, and the suction force and friction force by the suction pad 10 can be increased.

  Although the air blow path may be provided separately from the emergency exhaust path 30 and the like, the emergency exhaust path 30 including the reserve tank 31, the compressor 32, and the like can be used as the air blow path. This is because the air blow can be performed by operating the piston of the reserve tank 31 in the direction opposite to that for emergency exhaust. If both the paths are made common in this way, only one path including the reserve tank 31 and the compressor 32 is required, so that the joining device 1 can be simplified and reduced in weight.

In FIG. 6, the joining device 1 is provided with a gripping portion 5 for gripping the tip end portion of the stud bolt A and an air cylinder 3 for pressing down the stud bolt A together with the gripping portion 5. 3 can be arranged to be shared as the emergency exhaust path 30 described above. That is, by providing the air cylinder 3 with the function of moving the grip portion 5 back and forth (up and down in the drawing) and the function of operating the emergency exhaust path 30, the entire joining device 1 is simplified and reduced in weight. Specifically, the inside of the air cylinder 3 shown in FIG. 6 is allowed to communicate with the front portion of the suction pad 10 (the space between the workpieces B), and in the event of an emergency, the air cylinder 3 is designed after such communication. The emergency exhaust is performed from the front portion by extending the front side.
In this case, the operation procedure of the emergency exhaust path 30 is as follows. (1) When the degree of vacuum is reduced due to a part of the normal exhaust path 20 being damaged or the like, (2) the normal exhaust path 20 is shut off, and (3) the joining device 1 is emergency stopped (for example, the grip 5 is raised) (4) The degree of vacuum of the front surface portion (between the surface of the workpiece B) is ensured by the emergency exhaust path 30.

It is a figure which shows the outline | summary of the friction stud joining apparatus 1, Comprising: (a) is a front view, (b) is a bottom view, (c) is cc sectional drawing in (b). It is a perspective view which shows the state which fixed the friction stud joining apparatus 1 to the surface of the workpiece | work B using the suction pad 10. FIG. An embodiment is shown about suction pad 10 of an invention, (a) is a front sectional view, and (b) is an enlarged view of section b in (a). The other embodiment about the suction pad 10 of invention is shown, (a) is a bottom view of the suction pad 10 formed in the rectangle, (b) is a bottom view of the suction pad 10 formed in the circle. is there. It is a conceptual diagram which shows one Embodiment about the exhaust structure of the suction pad 10 of invention. It is a conceptual diagram which shows other embodiment about the exhaust structure of the suction pad 10 of invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Friction stud joining apparatus 3 Air cylinder 10 Adsorption pad 11 Pad main body 13 Insertion port 14 Airtight material 15 Anti-slip member 16 Dust seal 17 Intake hole 18 Adsorption area 20 Normal exhaust route 30 Emergency exhaust route A Stud bolt B Workpiece θ Non-slip member Inclination angle

Claims (6)

A friction stud joining device for joining a stud bolt to the surface of a workpiece by a friction stud joining method, is a suction pad for fixing to the surface of the workpiece,
In addition to having a suction hole connected to the vacuum pump in the front part that is disposed opposite to the work surface and surrounding it with an airtight material that seals between the front part and the work, the airtight material is A suction pad for a friction stud joining device, which further comprises a non-slip member.   The suction pad of the friction stud joining device according to claim 1, wherein the front portion includes a plurality of suction areas each having the suction hole and the airtight material.   The suction pad of the friction stud joining device according to claim 1 or 2, wherein the anti-slip member has a curved surface or an inclined surface on the surface of the workpiece.   The suction pad of the friction stud joining device according to any one of claims 1 to 3, wherein the airtight material is formed of a sponge having closed cells or a sponge made of synthetic resin.   5. The friction stud joining device according to claim 1, wherein a dust seal for protecting the hermetic material is provided closer to the stud bolt insertion position than the hermetic material. pad.   A friction stud joining apparatus for joining a stud bolt to a work surface by a friction stud joining method, wherein the suction pad according to any one of claims 1 to 5 is integrally provided at a front portion. Stud joint device.

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