JP7765702B2 - Method for manufacturing lap joint of organic layer coated metal sheets, and apparatus for manufacturing lap joint of organic layer coated metal sheets - Google Patents

Description

The present invention relates to a method for manufacturing a lap joint of organic layer-coated metal sheets and an apparatus for manufacturing a lap joint of organic layer-coated metal sheets.

Metal plate lap joints, obtained by joining plates made up of multiple overlapping metal plates, are found in the joints of various mechanical parts. The most commonly used method for joining metal plates is welding. Examples of welding methods used to join plate assemblies include spot welding, arc welding, and laser welding.

However, during welding, the joint is heated to a temperature above the melting point of the metal plates. This can cause the mechanical properties of the metal plates to deteriorate at the joint and its surrounding area. This phenomenon is particularly noticeable in steel plates, especially high-strength steel plates with a tensile strength of 780 MPa or more.

Additionally, welding is not suitable for joining dissimilar materials. When dissimilar materials are melted and mixed and then solidified, large amounts of brittle intermetallic compounds are formed in the weld metal. As a result, it is difficult to ensure sufficient joint strength when welding dissimilar materials.

Friction welding has been gaining attention in recent years as another method for joining metal plates. Friction welding is a pressure welding process in which two parts are brought into contact with each other and pressure is applied using frictional heat (raising the temperature near the joint) generated by rotating one or both parts or another friction element (JIS Z 3001-2:2018).

Friction welding is sometimes called friction welding. However, friction welding does not usually involve melting or solidifying the welded area. In friction welding, the surface of the base material is removed, and the newly exposed surface is heated by frictional heat to a temperature below the melting point, activated, and then pressurized to form the welded area. Therefore, friction welded areas usually do not contain weld metal.

Friction welding has traditionally been used to join rod-shaped materials such as pipes longitudinally. For example, Patent Document 1 discloses a friction welding method for propeller shafts in which a thin-walled pipe and a thick-walled pipe are arranged coaxially and their end faces are abutted and rotated relative to each other, generating frictional heat to press the end faces together, characterized in that the inner diameter of the thin-walled pipe is smaller than the inner diameter of the thick-walled pipe.

However, in recent years, attempts have been made to use friction welding to join multiple metal plates in an overlapping manner, using a rivet-like connecting member with a head and a shank. In this friction welding method, a connecting member having a shank and a head is pressed into the sheet assembly until the tip of the shank contacts the metal plate arranged on the outermost surface of the sheet assembly. The tip of the shank is then friction-welded to the metal plate arranged on the outermost surface of the sheet assembly. As a result, the metal plate friction-welded to the tip of the shank and the head provided at the base end of the shank sandwich the metal plate passed through by the shank, mechanically joining the sheet assembly. Lap joining of metal plates by friction welding can be said to be a joining method that combines friction welding and mechanical joining.

When joining metal plates using friction welding, the metal plates do not melt or mix together. Therefore, friction welding makes it easy to join metal plates made of different materials. Furthermore, the heat input during friction welding is less than that during welding. Therefore, friction welding is less likely to cause thermal degradation of the joint and its surrounding area.

As an example of a technology for joining metal plates using friction welding, Patent Document 2 discloses an apparatus that joins at least two flat plates, one of which is a support plate with greater strength than the other supported plate placed on top of it, using a joining element rotated by a rotary feeder unit. The joining element presses the supported plate against the support plate with a collar and forms a friction welded joint with the support plate via a shaft. The rotary feeder unit is equipped with a measuring device that measures the axial force and each feed distance applied by the rotary feeder unit, sends a signal indicating an increase in pressing force caused by lowering the shaft unit of the joining element, and advances the rotary feeder unit. The apparatus completes the friction welding process by adjusting the feed movement of the rotary feeder unit through at least three consecutive joining stages: a first stage for adjusting the feed so that the rotary feeder penetrates the supported plate; a second stage for adjusting the friction welding between the shaft unit and the support plate; and a third stage for applying the axial force of the joining element to the support plate.

Japanese Patent Application Laid-Open No. 2004-141933 JP 2011-062748 A

In recent years, there has been a demand for even higher corrosion resistance in metal lap joints. To improve corrosion resistance, it is preferable to coat the surface of a metal lap joint with an organic layer such as a paint film. However, welding is not suitable for joining metal plates whose surfaces are coated with an organic layer, i.e., organic layer-coated metal plates. When organic layer-coated metal plates are welded, the organic layer or gases generated from the organic layer become mixed into the weld metal, causing welding defects. For this reason, it is difficult to ensure sufficient joint strength when welding organic layer-coated metal plates. Furthermore, if the organic layer is an insulator, it is difficult to perform resistance welding such as spot welding.

The inventors therefore attempted to join metal plates coated with an organic layer by friction welding. As a result, they confirmed that the organic layer did not interfere with friction welding and that good joint strength could be ensured.

On the other hand, when organic layer-coated metal plates are joined by friction welding, it has been found that the organic layer deteriorates and peels off around the connecting member, as shown in Figure 4. The corrosion resistance of the metal plate lap joint is impaired where the organic layer peels off. This peeling of the organic layer is likely to occur when multiple joints are performed consecutively. There have been no previous reports of organic layer deterioration or peeling when organic layer-coated metal plates are joined consecutively multiple times by friction welding. Therefore, the organic layer deterioration phenomenon discovered by the inventors is unknown to those skilled in the art. Incidentally, there have been reported cases of friction welding metal plates having metal plating such as Zn plating instead of an organic layer, but in these cases, plating degradation was not a concern.

In light of the above circumstances, the present invention aims to provide a method and apparatus for manufacturing an organic layer-coated metal sheet lap joint that can suppress deterioration of the organic layer more than conventional methods when friction welding organic layer-coated metal sheets.

The gist of the present invention is as follows:

(1) A method for manufacturing an organic layer coated metal sheet lap joint according to a first embodiment of the present invention includes the steps of: fixing a sheet assembly made up of a plurality of overlapping metal sheets to an anvil; press-fitting a connecting member having a shank and a head provided at the base end of the shank into the sheet assembly from the opposite side of the anvil until the metal sheet in contact with the anvil comes into contact with the tip of the shank; friction-welding the metal sheet in contact with the anvil and the tip of the shank, and using the head to weld the metal sheet through which the shank has penetrated to the metal sheet through which the shank has been friction-welded. and a step of mechanically joining the plate to the anvil, wherein in the fixing step, the plate set is fixed to the anvil by pressing a cylindrical sleeve against the plate set from the opposite side of the anvil, and in the pressing step, the connecting member is pressed into the plate set through the inside of the sleeve, an organic material layer is disposed on one or both surfaces of the plate set, and when the organic material layer and the sleeve come into contact, the organic material layer is cooled using the sleeve, and when the organic material layer and the anvil come into contact, the organic material layer is cooled using the anvil.
(2) In the manufacturing method of the organic material layer-coated metal sheet lap joint described in (1) above, when the organic material layer and the sleeve are in contact with each other, the organic material layer may be cooled by making the sleeve out of copper or a copper alloy and/or by providing the sleeve with a cooling mechanism using a refrigerant, and when the organic material layer and the anvil are in contact with each other, the organic material layer may be cooled by making the anvil out of copper or a copper alloy and/or by providing the anvil with a cooling mechanism using a refrigerant.
(3) In the manufacturing method of the organic material layer-coated metal sheet lap joint described in (1) above, when the organic material layer and the sleeve are in contact with each other, the organic material layer may be cooled by providing a refrigerant-based cooling mechanism on the sleeve, and when the organic material layer and the anvil are in contact with each other, the organic material layer may be cooled by providing a refrigerant-based cooling mechanism on the anvil.
(4) In the method for manufacturing a lap joint of organic layer-coated metal sheets according to any one of (1) to (3) above, the organic layer may be in contact with the sleeve.
(5) In the method for manufacturing a lap joint of organic layer-coated metal sheets described in (4) above, a chamfer having a radius of 0.1 mm or more may be provided on the inner edge of the end face of the sleeve that contacts the organic layer.
(6) A manufacturing method of an organic substance layer-coated metal sheet lap joint according to a second embodiment of the present invention includes the steps of: fixing a sheet assembly consisting of a plurality of overlapping metal sheets to an anvil; pressing a connecting member having a shaft and a head provided at the base end of the shaft into the sheet assembly from the opposite side of the anvil until the metal sheet in contact with the anvil comes into contact with the tip of the shaft; friction-welding the metal sheet in contact with the anvil to the tip of the shaft, and mechanically joining the metal sheet through which the shaft has penetrated to the metal sheet to which the shaft has been friction-welded, using the head; and an organic substance layer is disposed on at least the surface of the sheet assembly in contact with the anvil, and cooling the organic substance layer using the anvil.
(7) In the manufacturing method of the organic layer coated metal sheet lap joint described in (6) above, the organic layer may be cooled by making the anvil out of copper or a copper alloy and/or by providing the anvil with a cooling mechanism using a refrigerant.
(8) In the method for manufacturing a lap joint of organic layer-coated metal sheets described in (6) above, the organic layer may be cooled by providing a cooling mechanism that uses a refrigerant on the anvil.
(9) In the method for manufacturing a lap joint of organic layer-coated metal sheets according to any one of (1) to (8) above, one or more of the plurality of metal sheets may be a steel sheet.

(10) A manufacturing apparatus for an organic material layer-coated metal sheet lap joint according to a third embodiment of the present invention includes an anvil configured to fix a sheet assembly consisting of a plurality of overlapping metal sheets, a rotary pressing mechanism that presses a connecting member having a shaft portion and a head portion provided at the base end of the shaft portion against the sheet assembly from the opposite side of the anvil while rotating the connecting member around the axis of the connecting member, and a cylindrical sleeve that is pressed against the sheet assembly from the opposite side of the anvil to fix the sheet assembly, wherein the rotation axis of the rotary pressing mechanism is inside the sleeve, the sleeve has a cooling means, and the sleeve cools the organic material layer .
(11) In the manufacturing apparatus for an organic layer-coated metal sheet lap joint described in (10) above, the cooling means may be one or both of the sleeve itself made of copper or a copper alloy and a refrigerant-based cooling mechanism provided on the sleeve .
(12) In the manufacturing apparatus for a lap joint of organic layer-coated metal sheets described in (10) above, the cooling means may be a cooling mechanism that uses a refrigerant and is provided in the sleeve .
( 13 ) In the manufacturing device for an organic layer coated metal sheet lap joint described in ( 10 ) above, the sleeve may have a chamfered portion with a radius of 0.1 mm or more on the inner edge of the end surface that contacts the organic layer .

The present invention provides a method and apparatus for manufacturing an organic layer-coated metal sheet lap joint that can suppress deterioration of the organic layer more than conventional methods when friction welding organic layer-coated metal sheets.

1 is a schematic diagram of a method for manufacturing an organic layer-coated metal sheet lap joint according to a first embodiment. FIG. FIG. 10 is a cross-sectional schematic view of a cooling mechanism for the anvil and sleeve. 5 is a schematic diagram of a method for manufacturing an organic layer-coated metal sheet lap joint according to a second embodiment. FIG. 1 is a schematic diagram of a method for manufacturing an organic layer-coated metal sheet lap joint using a conventional metal sheet lap joint manufacturing apparatus. FIG.

The method for manufacturing an organic layer-coated metal sheet lap joint according to the first embodiment of the present invention includes the steps of:
(S1) a step of fixing a plate set B composed of a plurality of overlapping metal plates B1 and B2 to an anvil 11;
(S2) a step of press-fitting a connecting member C having a shaft portion C2 and a head portion C1 provided at a base end of the shaft portion C2 into the plate assembly B from the opposite side of the anvil 11 until the first metal plate B1 in contact with the anvil 11 comes into contact with the tip end of the shaft portion C2;
(S3) frictionally welding the first metal plate B1 in contact with the anvil 11 to the tip of the shank C2, and mechanically joining the second metal plate B2, through which the shank C2 has penetrated, to the first metal plate B1, to which the shank C2 has been frictionally welded, by the head C1;
Here, in the fixing step S1, a cylindrical sleeve 12 is pressed against the plate set B from the opposite side of the anvil 11, thereby fixing the plate set B to the anvil 11, and in the press-fitting step S2, a connection member C is pressed against the plate set B through the inside 122 of the sleeve 12. An organic layer E is disposed on one or both surfaces of the plate set B, and when the organic layer E and the sleeve 12 contact each other, the organic layer E is cooled using the sleeve 12, and when the organic layer E and the anvil 11 contact each other, the organic layer E is cooled using the anvil 11.

The organic layer-coated metal sheet lap joint A obtained by the above-described method comprises a sheet assembly B consisting of a first metal sheet B1 arranged as the outermost layer and one or more second metal sheets B2 overlapping the first metal sheet B1; a connecting member C friction-welded perpendicularly to the first metal sheet B1 and having a shaft C2 that passes through the second metal sheet B2, and a head C1 provided at the base end of the shaft C2 that mechanically joins the first metal sheet B1 and the second metal sheet B2; and one or both surfaces of the sheet assembly B are coated with an organic layer E.

The method for manufacturing an organic layer-coated metal sheet lap joint according to the first embodiment is described in detail below.

(Fixing process S1)
First, a plate set B consisting of a plurality of overlapping metal plates is fixed to an anvil 11. Here, an organic layer E is disposed on one or both surfaces of the plate set B. This makes it possible to manufacture an organic layer-coated metal plate lap joint A whose surfaces are coated with the organic layer E. The number of metal plates included in the plate set B may be two, three or more.

For convenience, the metal plate arranged on the outermost layer of the plate assembly B and in contact with the anvil 11 will be referred to as the first metal plate B1, and the other metal plates will be referred to as the second metal plates B2. The first metal plate B1 is the metal plate to which the tip of the shank C2 of the connecting member C is friction-welded, and the second metal plate B2 is the metal plate through which the shank C2 of the connecting member C passes. There is one first metal plate B1. There may be one or more second metal plates B2.

In the manufacturing method according to the first embodiment, the plate assembly B is fixed to the anvil 11 by a cylindrical sleeve 12. Specifically, the cylindrical sleeve 12 is vertically abutted against the surface of the plate assembly B on the opposite side of the anvil 11. The sleeve 12 is then pressed against the plate assembly B from the opposite side of the anvil 11. Note that a fixing jig other than the sleeve 12 may be used in combination to more firmly fix the plate assembly B to the anvil 11.

(Press-fitting step S2)
The head C1 provided at the base end of the shaft C2 is connected to the rotary pressing mechanism 13 of the manufacturing apparatus 1 for the organic layer-coated metal sheet lap joint A. The head C1 provided at the base end of the shaft C2 may be connected to the rotary pressing mechanism 13 in advance of the fixing step S1. The connecting member C is pressed perpendicularly against the plate assembly B from the opposite side of the anvil 11, and the tip of the shaft C2 is brought into contact with the plate assembly B.

Then, by rotating and pressing the connecting member C, the shaft portion C2 of the connecting member C is pressed into the plate assembly B, penetrating the metal plates. Because the plate assembly B is fixed to the anvil 11, the connecting member C rotates relative to the plate assembly B during the press-fitting step S2 and subsequent steps. The connecting member C is also pressed against the plate assembly B through the inner surface 122 of the sleeve 12. This allows the sleeve 12 to secure the periphery of the connecting member C with an even pressure force, stabilizing the joining process. As mentioned above, in this embodiment, the metal plate being penetrated is referred to as the second metal plate B2.

The press-fitting step S2 continues until the tip of the shank C2 of the connecting member C comes into contact with the metal plate in contact with the anvil 11, i.e., the first metal plate B1. By making the length of the shank C2 of the connecting member C sufficiently longer than the total thickness of the second metal plate B2, the tip of the shank C2 can come into contact with the first metal plate B1. Furthermore, to facilitate penetration, it is preferable that the tip of the shank C2 of the connecting member C be pointed rather than flat. However, the press-fitting step S2 is a process in which the tip of the shank C2 of the connecting member C penetrates the second metal plate B2 and contacts the first metal plate B1, and the method for this is not important. As described above, the connecting member C may be pressed while being rotated to penetrate the second metal plate B2, or a through-hole may be pre-formed in the second metal plate B2, and the connecting member C may be pressed without being rotated to penetrate the second metal plate B2.

(Friction welding step S3)
By further rotating and pressing the connecting member C, the contact area between the tip of the shank C2 and the first metal plate B1 is heated. Furthermore, at the contact area, the tip of the shank C2 and the outermost surface of the first metal plate B1 are removed, revealing a new surface. When the rotation of the connecting member C is stopped, the new surface is immediately cooled by heat transfer from the new surface to the surrounding area. The two activated new surfaces are then firmly joined after cooling, forming a friction weld D.

When the tip of the shank C2 of the connecting member C is friction-welded to the first metal plate B1, the second metal plate B2 is positioned between the first metal plate B1 joined to the tip of the connecting member C and the head C1 provided at the base end of the connecting member C. In other words, the head C1 of the connecting member C mechanically joins the second metal plate B2, through which the shank C2 of the connecting member C passes, to the first metal plate B1 to which the shank C2 of the connecting member C is friction-welded.

Through the above steps, an organic layer-coated metal sheet lap joint A is obtained in which one or both surfaces are coated with an organic layer E. However, the present inventors have discovered that the organic layer E disposed on the surface may peel off, as shown in Figure 4. The present inventors have examined the peeled portion in detail and have confirmed the following facts.
(1) As shown in FIG. 4, when the sleeve 12 and the organic layer E were in contact with each other, the organic layer E peeled off at the location where the sleeve 12 was pressed.
(2) As shown in FIG. 4, when the anvil 11 and the organic layer E were in contact with each other, the organic layer E peeled off at the location where the connecting member C was pressed.
(3) When friction welding was performed multiple times in a short period of time using one joining device, the incidence of peeling increased as the number of times it was performed increased.

Previously, the harmful effects of frictional heat in friction welding were not recognized. In resistance welding such as spot welding, the weld is cooled via the electrode to prevent electrode deterioration due to welding heat and promote solidification of the molten metal. However, in friction welding, the connection member C is replaced with a new one each time a joint is joined. Therefore, thermal degradation of the connection member C and its surrounding components was not considered a problem. Rather, excessive cooling of the connection member C was considered undesirable, as it facilitates plastic deformation of the connection member and promotes the creation of a new, activated surface. In prior art, cooling of the friction-welded area meant cooling after the rotational pressure of the connection member was stopped. Furthermore, the adverse effects of frictional heat on surface treatment were not known. In fact, when friction welding was performed using the above procedure on zinc-plated steel sheets, which have a relatively low melting point, no peeling of the zinc plating occurred.

However, the inventors hypothesized that the frictional heat generated during the press-fitting step S2 through the friction welding step S3 was transferred to and accumulated in the sleeve 12 and anvil 11, causing the temperature to rise at the contact points between the sleeve 12 and/or anvil 11 and the plate assembly B, which in turn caused the deterioration of the organic layer E.

The inventors therefore attempted to provide cooling means to the sleeve 12 and anvil 11 to cool the organic layer E in contact with the sleeve 12 and/or anvil 11 during the press-fitting step S2 through the friction welding step S3. As a result, they were able to prevent the organic layer E from peeling off. Furthermore, even when the organic layer E was cooled using the sleeve 12 and anvil 11, friction welding was not hindered, and good joint strength was ensured.

Based on the above findings, in the manufacturing method for organic layer-coated metal sheet lap joint A according to the first embodiment, the organic layer E is cooled using a fixture that comes into contact with the organic layer E during the steps S2 through S3 of press-fitting. Specifically, when the organic layer E comes into contact with the sleeve 12, the organic layer E is cooled using the sleeve 12, and when the organic layer E comes into contact with the anvil 11, the organic layer E is cooled using the anvil 11.

As described above, the organic material layer E may be provided on only one surface of the plate assembly B, or on both surfaces. Furthermore, when the organic material layer E is provided on only one surface of the plate assembly B, the organic material layer E may be provided on the anvil 11 side or on the side opposite the anvil 11. When the organic material layer E is provided only on the anvil 11 side, it is sufficient to cool the organic material layer E using at least the anvil 11. When the organic material layer E is provided only on the sleeve 12 side, it is sufficient to cool the organic material layer E using at least the sleeve 12. When the organic material layer E is provided on both the anvil 11 side and the sleeve 12 side, it is sufficient to cool the organic material layer E using both the anvil 11 and the sleeve 12. Furthermore, when the organic material layer E is provided on only one surface of the plate assembly B, it is also possible to cool the organic material layer E and the metal plate using both the anvil 11 and the sleeve 12.

Note that "cooling" refers to cooling the metal plate to a degree that suppresses the temperature rise caused by friction welding. For example, even if the anvil 11 and sleeve 12 are made of an ordinary material, such as steel, some heat transfer occurs from the metal plate to the anvil 11 and sleeve 12 during friction welding. However, because steel cannot sufficiently suppress the temperature rise caused by friction welding, such heat transfer does not constitute cooling in this embodiment.

The cooling means is not particularly limited. One suitable example of a cooling means is to use a metal with high thermal conductivity for the material of the anvil 11 and/or sleeve 12. For example, by making the anvil 11 and/or sleeve 12 from copper or a copper alloy, heat transfer from the anvil 11 and/or sleeve 12 to the device body can be promoted, cooling the organic layer E. The thermal conductivity of the material of the anvil 11 and/or sleeve 12 is preferably 220 W/mK or higher, and more preferably 280 W/mK or higher.

Another suitable example of a cooling means is to provide the anvil 11 and/or sleeve 12 with a refrigerant-based cooling mechanism 111, 121, as shown in Figure 2. The anvil 11 and/or sleeve 12 may be made of copper or a copper alloy and provided with the refrigerant-based cooling mechanism 111, 121. Note that in Figure 2, the cooling mechanism 121 is depicted as a device that sprays refrigerant toward the work table from the rear side of the work table for the anvil 11. The cooling mechanism 121 is also depicted as a refrigerant flow path extending from the front side to the back side of the page. However, naturally, various configurations can be applied to the cooling mechanisms 111, 121 depending on the application. For example, heat-conductive materials other than copper and copper alloys, as well as Peltier elements, can also be used as cooling means.

Furthermore, according to the results of experiments conducted by the inventors, the sleeve 12 caused peeling of the organic layer E more frequently than the anvil 11. However, as described above, peeling can be prevented by cooling the organic layer E using the sleeve 12. Therefore, when the sheet assembly B is arranged so that the organic layer E and the sleeve 12 are in contact, the manufacturing method for organic layer-coated metal sheet lap joints according to this embodiment demonstrates even greater advantages over conventional manufacturing methods.

Furthermore, as a result of detailed analysis of the peeled portion of the organic layer E, the inventors discovered that warping of the second metal plate B2 in contact with the sleeve 12 can also lead to peeling of the organic layer E. When the shank C2 of the connecting member C is inserted through the second metal plate B2, the second metal plate B2 can warp toward the base end of the shank C2. This can cause the inner edge of the end face of the sleeve 12 that contacts the organic layer E to slightly damage the organic layer E.

Therefore, a chamfered portion 123 with a radius of 0.1 mm or more may be provided on the inner edge of the end surface of the sleeve 12 that comes into contact with the organic layer E. This eliminates the risk of the inner edge of the end surface of the sleeve 12 damaging the organic layer E, and more effectively prevents peeling of the organic layer E. The chamfered portion 123 preferably has a radius of 0.2 mm or more, and more preferably a radius of 0.3 mm or more. Note that typical sleeves 12 are manufactured by means such as drilling holes in a rod-shaped material, and do not have a chamfered portion 123 formed on the inner edge of the end surface of such sleeves 12.

Next, a method for manufacturing a lap joint of organic layer-coated metal sheets according to a second embodiment of the present invention will be described.
(S1) a step of fixing a plate set B composed of a plurality of overlapping metal plates to an anvil 11;
(S2) a step of press-fitting a connecting member C having a shaft portion C2 and a head portion C1 provided at a base end of the shaft portion C2 into the plate assembly B from the opposite side of the anvil 11 until the first metal plate B1 in contact with the anvil 11 comes into contact with the tip of the shaft portion C2;
(S3) frictionally welding the first metal plate B1 in contact with the anvil 11 to the tip of the shank C2, and mechanically joining the second metal plate B2, through which the shank C2 has penetrated, to the metal plate to which the shank C2 has been frictionally welded by the head C1;
Here, an organic layer E is disposed on at least the surface of the plate assembly B that contacts the anvil 11, and the organic layer E is cooled using the anvil 11. Hereinafter, the manufacturing method according to the second embodiment will be described in detail in comparison with the first embodiment.

The manufacturing method for an organic layer-coated metal sheet lap joint according to the second embodiment is essentially the same as the manufacturing method according to the first embodiment. However, in the manufacturing method according to the second embodiment, the process of fixing the sheet assembly B to the anvil 11 is not particularly limited. Unlike the first embodiment, the use of a sleeve 12 in the second embodiment is not essential. For example, the sheet assembly B can be fixed to the anvil 11 using a fixing jig such as a clamp, which is not shown in Figure 3. If the sleeve 12 is not used, the connecting member C can be pressed and joined at any location on the sheet assembly B. Furthermore, in the manufacturing method according to the second embodiment, the organic layer E is disposed at least on the surface of the sheet assembly B that contacts the anvil 11. The anvil 11 is then used to cool the organic layer E disposed on the anvil 11 side.

Furthermore, preferred aspects of the manufacturing method according to the first embodiment can also be applied to the manufacturing method according to the second embodiment. For example, the organic layer E may be cooled by making the anvil 11 out of copper or a copper alloy and/or by providing the anvil 11 with a cooling mechanism 111, 121 that uses a refrigerant.

The basic aspects of the manufacturing methods according to the first and second embodiments have been described above. Next, we will explain more preferred aspects that are commonly applicable to both.

(Suitable examples of metal plates)
The type of metal plate is not particularly limited. The materials of the multiple metal plates included in the plate set B may be the same or different. For example, one or more of the multiple metal plates may be steel plates. This can increase the strength of the organic layer-coated metal plate lap joint A. All of the multiple metal plates may be steel plates.

Note that the rotational force and pressing force required to penetrate the shank C2 of the connecting member C is greater and takes a longer time when using a steel plate than when using a soft metal plate such as an aluminum plate. Therefore, when the second metal plate B2 is a steel plate, the temperature of the organic material layer E is likely to rise, and therefore the organic material layer E is likely to peel off. However, in the manufacturing methods of the first and second embodiments, the organic material layer E is cooled by the anvil 11 and/or sleeve 12, so peeling of the organic material layer E can be effectively prevented even if one or more of the multiple metal plates is a steel plate.

Also, prior to performing the press-fitting step S2, a hole for passing the shank C2 of the connecting member C may be pre-formed in the second metal plate B2. This is particularly effective when the second metal plate B2 is made of a hard material such as a steel plate. This makes it easier to perform the press-fitting step S2. Specifically, the shank C2 of the connecting member C can be passed through in a short time. Furthermore, the shank C2 of the connecting member C can be passed through without having to rotate the connecting member C. The shape of the hole formed in the second metal plate B2 is not particularly limited, as long as it has a diameter smaller than the diameter of the head C1 of the connecting member C. Unlike bolt fastening, the diameter of the hole formed in the second metal plate B2 may be smaller than the thickness of the shank C2 of the connecting member C. This is because the connecting member C is press-fitted into the plate assembly B.

(Suitable Examples of Organic Layer E)
The organic layer E is a surface coating layer containing an organic substance and is used, for example, to improve the corrosion resistance and aesthetics of metal sheet lap joints. One example of the organic layer E is a coating film primarily composed of an organic substance. To further improve the properties of the organic layer E, additives composed of inorganic substances or metals may be added to the organic layer E. Another example of the organic layer E is a coating film using an organic substance as a binder. In this case, even if the organic substance content is low, there is a risk of the organic substance degrading and the organic layer peeling during normal friction welding. The organic substance contained in the organic layer E is not particularly limited, but the present invention is more effectively applied to organic layer E containing an organic substance with a glass transition temperature of 50°C or less, since it is easily softened and peeled by heat. An intermediate layer, such as a plating or a chemical conversion coating, may be further provided between the organic layer E and the metal sheet.

As described above, organic layer E is disposed on one or both surfaces of plate set B. Alternatively, both sides of the metal plates included in plate set B may be coated with organic layer E, thereby disposing organic layer E on the mating surfaces of the metal plates inside plate set B. Adhesives, sealants, etc. may be applied to the mating surfaces of the metal plates included in plate set B.

The configuration of the connecting member C and the friction welding conditions are not particularly limited. In the manufacturing methods according to the first and second embodiments, peeling of the organic material layer E is prevented by cooling the organic material layer E using the anvil 11 and/or sleeve 12. Therefore, the joining conditions are not particularly limited, and conditions can be appropriately adopted depending on the configuration of the multiple metal plates that are the materials to be joined.

Next, we will explain the manufacturing apparatus 1 for organic substance layer-coated metal sheet lap joints according to a third embodiment of the present invention. The manufacturing apparatus 1 for organic substance layer-coated metal sheet lap joints according to the third embodiment includes an anvil 11 configured to secure a sheet assembly B composed of multiple overlapping metal sheets; a rotary pressing mechanism 13 that presses a connecting member C, which has a shaft portion C2 and a head portion C1 provided at the base end of the shaft portion C2, against the sheet assembly B from the opposite side of the anvil 11 while rotating the connecting member C around the axis of the connecting member C; and a cylindrical sleeve 12 that is pressed against the sheet assembly B from the opposite side of the anvil 11 to secure the sheet assembly B. The rotation axis of the rotary pressing mechanism 13 is located inside 122 of the sleeve 12, and one or both of the anvil 11 and the sleeve 12 have cooling means.

The anvil 11 and the cylindrical sleeve 12 secure the plate assembly B. One or both of the anvil 11 and the sleeve 12 have cooling means capable of cooling the organic layer E formed on the surface of the plate assembly B. This prevents the organic layer E from peeling off. Because the sleeve 12 is more likely to cause the organic layer E to peel off, it is preferable to provide a cooling means on the sleeve 12.

The cooling means is not particularly limited, but for example, one or both of the anvil 11 and the sleeve 12 may be made of copper or a copper alloy, and these themselves may serve as the cooling means. Alternatively, the cooling means may be a refrigerant-based cooling mechanism 111, 121 provided on one or both of the anvil 11 and the sleeve 12. Both of these cooling means may also be employed. That is, more preferably, one or both of the anvil 11 and the sleeve 12 are made of copper or a copper alloy and have a refrigerant-based cooling mechanism 111, 121.

The sleeve 12 may have a chamfered portion 123 with a radius of 0.1 mm or more on the inner edge of the end surface that comes into contact with the organic layer E. This eliminates the risk of the inner edge of the end surface of the sleeve 12 damaging the organic layer E, and more effectively prevents peeling of the organic layer E.

The rotary pressing mechanism 13 presses the connecting member C, which has a shaft portion C2 and a head portion C1 attached to the base end of the shaft portion C2, against the plate assembly B while rotating it around the axis of the connecting member C from the opposite side of the anvil 11. This allows the connecting member C to rotate relative to the plate assembly B, thereby achieving friction welding. Note that in order to press the connecting member C into the plate assembly B through the cylindrical sleeve 12, the rotation axis of the rotary pressing mechanism 13 must be located on the inside 122 of the sleeve 12. The rotary pressing mechanism 13 may also include a gripping portion capable of gripping and rotating the head portion C1 of the connecting member C. On the other hand, if the head portion C1 of the connecting member C has a polygonal hole, the rotary pressing mechanism 13 may simply include a polygonal protrusion shaped to correspond to the polygonal hole in the head portion C1. The mechanism for rotating and pressing the connecting member C is not particularly limited, and any known configuration suitable for friction welding can be used as appropriate.

The use of the manufacturing apparatus 1 according to the third embodiment is not particularly limited, but it is suitable for carrying out the manufacturing method according to the first embodiment, for example.

Next, we will explain the manufacturing apparatus 1 for organic layer-coated metal sheet lap joints according to a fourth embodiment of the present invention. The manufacturing apparatus 1 for organic layer-coated metal sheet lap joints according to the fourth embodiment includes an anvil 11 configured to secure a sheet assembly B made up of multiple overlapping metal sheets, and a rotary pressing mechanism 13 that presses a connecting member C having a shaft portion C2 and a head portion C1 provided at the base end of the shaft portion C2 against the sheet assembly B from the opposite side of the anvil 11 while rotating the connecting member C around the axis of the connecting member C, and the anvil 11 has a cooling means.

The manufacturing apparatus 1 according to the fourth embodiment is essentially the same as the manufacturing apparatus 1 according to the third embodiment. However, the means for fixing the plate assembly B to the anvil 11 in the manufacturing apparatus 1 according to the fourth embodiment is not particularly limited. Unlike the third embodiment, the use of a sleeve 12 in the fourth embodiment is not required. For example, the manufacturing apparatus 1 may be provided with a fixing jig such as a clamp for fixing the plate assembly B to the anvil 11. If the sleeve 12 is not used, the connecting member C can be pressed and bonded to any location on the plate assembly B. Furthermore, the manufacturing apparatus 1 according to the fourth embodiment uses the anvil 11 to cool the organic material layer E arranged on the anvil 11 side. Note that if the manufacturing apparatus 1 according to the fourth embodiment does not include the sleeve 12, there is likely to be no risk of the organic material layer E arranged on the opposite side of the anvil 11 peeling off.

The use of the manufacturing apparatus 1 according to the fourth embodiment is not particularly limited, but it is suitable for carrying out the manufacturing method according to the second embodiment, for example.

The effects of one aspect of the present invention will be explained in more detail using examples. However, the conditions in the examples are merely an example of conditions adopted to confirm the feasibility and effects of the present invention. The present invention is not limited to this example of conditions. Various conditions may be adopted in the present invention as long as they do not deviate from the gist of the present invention and the objectives of the present invention are achieved.

Various organic layer-coated metal sheet lap joints were produced by friction welding two steel sheets, as shown below, fixed to an anvil using a sleeve. When a painted first metal sheet was placed on top of an unpainted second metal sheet, various cooling methods were applied to the anvil, and peeling of the organic layer of the first metal sheet was evaluated. When a painted second metal sheet was placed on top of an unpainted first metal sheet, various cooling methods were applied to the sleeve, and peeling of the organic layer of the second metal sheet was evaluated.

Friction welding was performed at 30 mm intervals, every 10 seconds, for a maximum of 100 points. After completion of the joining, the surface of the organic layer-coated metal sheet lap joint was visually observed to check for peeling of the organic layer. The evaluation criterion was the number of times of joining until the first peeling of the coating film occurred.
・The number of bonding cycles before the first peeling of the coating is 91 or more: ◎
The number of times the coating film is bonded until peeling occurs for the first time is 21 to 90 times: ○
- The number of bonding times until the coating film first peeled off was 6 or more and 20 or less: △
- The number of times the coating is bonded until peeling occurs for the first time is 1 to 5 times: ×

The sleeve and anvil were made of four types: steel, copper, steel with a water-cooling mechanism, and copper with a water-cooling mechanism. In some experiments, the sleeve was chamfered with a radius of 0.1 mm on the inner edge of the end face that came into contact with the organic layer.
The evaluation results for the organic layer in contact with the sleeve are shown in Table 2. To obtain the experimental results shown in Table 2, the anvil was made of steel, the sleeve was one of the four types described above, and the plate assembly was assembled in a joining device so that the organic layer was disposed on the surface of the plate assembly in contact with the sleeve.
Table 3 shows the evaluation results for the organic layer in contact with the anvil. To obtain the experimental results shown in Table 3, the anvil was one of the four types described above, the sleeve was made of steel, and the plate assembly was assembled into the joining device so that the organic layer was disposed on the surface of the plate assembly in contact with the anvil.
The test results for the case where the sleeve was provided with a chamfered portion are added to Table 2 in parentheses.

In the comparative example in which both the sleeve and the anvil were made of steel, peeling occurred very early in both the organic layer on the anvil side and the organic layer on the sleeve side.
When the sleeve was made of steel and the anvil was made of copper or had a water-cooling mechanism, peeling of the organic layer on the anvil side was suppressed.
Furthermore, when the anvil was made of steel and the sleeve was made of copper or had a water-cooling mechanism, peeling of the organic layer on the sleeve side was suppressed.
Furthermore, it was confirmed that providing a chamfered portion on the sleeve prevented peeling of one organic layer in some cases.

1 Manufacturing apparatus 11 Anvil 111 Cooling mechanism 12 Sleeve 121 Cooling mechanism 122 Inner side of sleeve 123 Chamfered portion 13 Rotary pressing mechanism A Organic layer coated metal plate lap joint B Plate set B1 First metal plate B2 Second metal plate C Connecting member C1 Head C2 Shaft portion D Friction welding portion E Organic layer S1 Fixing process S2 Press-fit process S3 Friction welding process

Claims (13)

a step of fixing a plate set composed of a plurality of overlapping metal plates to an anvil;
a step of press-fitting a connecting member having a shaft portion and a head portion provided at a base end of the shaft portion into the plate assembly from the opposite side of the anvil until a metal plate in contact with the anvil comes into contact with a tip end of the shaft portion;
a step of frictionally welding the metal plate in contact with the anvil and the tip of the shank, and mechanically joining the metal plate through which the shank has penetrated by the head to the metal plate to which the shank has been frictionally welded;
Equipped with
In the fixing step, a cylindrical sleeve is pressed against the plate set from the opposite side of the anvil to fix the plate set to the anvil;
In the press-fitting step, the connecting member is passed through the inside of the sleeve and press-fitted into the plate assembly,
An organic layer is disposed on one or both surfaces of the plate set,
A method for manufacturing a lap joint of organic material layer-coated metal sheets, wherein when the organic material layer and the sleeve are in contact with each other, the organic material layer is cooled using the sleeve, and when the organic material layer and the anvil are in contact with each other, the organic material layer is cooled using the anvil. When the organic layer is in contact with the sleeve, the sleeve is made of copper or a copper alloy and/or the sleeve is provided with a cooling mechanism that uses a refrigerant, thereby cooling the organic layer;
A method for manufacturing an organic layer-coated metal sheet lap joint as described in claim 1, characterized in that when the organic layer comes into contact with the anvil, the organic layer is cooled by making the anvil out of copper or a copper alloy and/or by providing the anvil with a cooling mechanism using a refrigerant. The method for manufacturing an organic material layer-coated metal sheet lap joint according to claim 1, characterized in that when the organic material layer and the sleeve come into contact, the organic material layer is cooled by providing a refrigerant-using cooling mechanism on the sleeve, and when the organic material layer and the anvil come into contact, the organic material layer is cooled by providing a refrigerant-using cooling mechanism on the anvil. A method for manufacturing an organic layer-coated metal sheet lap joint according to any one of claims 1 to 3, characterized in that the organic layer and the sleeve are in contact with each other. The method for manufacturing an organic layer-coated metal sheet lap joint described in claim 4, characterized in that a chamfer with a radius of 0.1 mm or more is provided on the inner edge of the end face of the sleeve that comes into contact with the organic layer. a step of fixing a plate set composed of a plurality of overlapping metal plates to an anvil;
a step of press-fitting a connecting member having a shaft portion and a head portion provided at a base end of the shaft portion into the plate assembly from the opposite side of the anvil until a metal plate in contact with the anvil comes into contact with a tip end of the shaft portion;
a step of frictionally welding the metal plate in contact with the anvil and the tip of the shank, and mechanically joining the metal plate through which the shank has penetrated by the head to the metal plate to which the shank has been frictionally welded;
Equipped with
an organic layer is disposed on at least the surface of the plate assembly that contacts the anvil;
The method for manufacturing a lap joint of organic layer-coated metal sheets includes cooling the organic layer using the anvil. The method for manufacturing an organic layer-coated metal sheet lap joint according to claim 6, characterized in that the organic layer is cooled by making the anvil out of copper or a copper alloy and/or by providing the anvil with a cooling mechanism using a refrigerant. 7. The method for manufacturing a lap joint of organic-substance-coated metal sheets according to claim 6, wherein the organic layer is cooled by providing a cooling mechanism that uses a refrigerant on the anvil. The method for manufacturing an organic layer coated metal plate lap joint according to any one of claims 1 to 8, characterized in that at least one of the plurality of metal plates is a steel plate. an anvil configured to fix a plate set made up of a plurality of overlapping metal plates;
a rotary pressing mechanism that rotates a connecting member having a shaft portion and a head portion provided at a base end of the shaft portion around the axis of the connecting member from the opposite side of the anvil while pressing the connecting member against the plate assembly;
a cylindrical sleeve that is pressed against the plate set from the opposite side of the anvil to fix the plate set;
Equipped with
a rotation shaft of the rotary pressing mechanism is located inside the sleeve;
the sleeve has a cooling means;
The sleeve cools the organic layer.
Manufacturing equipment for organic layer coated metal sheet lap joints. The cooling means
The sleeve itself is made of copper or a copper alloy; and
11. The manufacturing device for a lap joint of organic layer coated metal sheets according to claim 10, characterized in that one or both of the cooling mechanisms using a refrigerant are provided in the sleeve . 11. The manufacturing apparatus for a lap joint of organic layer coated metal sheets according to claim 10, wherein the cooling means is a cooling mechanism that uses a refrigerant and is provided in the sleeve . 11. The manufacturing device for a lap joint of organic layer-coated metal sheets according to claim 10 , wherein the sleeve has a chamfered portion with a radius of 0.1 mm or more on the inner edge of the end surface that comes into contact with the organic layer.