JP2020116600A - Joint method, joint device and joint structure of metal plates - Google Patents

Abstract

To provide a method for joining plural metal plates with joint strength higher than that of a caulking joint without using secondary materials.SOLUTION: A joint method in this invention includes: a mechanical joint process of overlapping plural metal plates 101, 102 to dispose on a die 20 having a recess and forming a joint part 110 having a side wall 111 and bottom 112 by pressurizing plural metal plates 101, 102 by a punch 10 to plastically deform to carry out a mechanical clinch joint; and an ultrasonic joint process of metallurgically joining the bottom 112 by imparting an ultrasonic wave to the bottom 112 of the joint part 110 formed in the mechanical joint process.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method of joining a plurality of metal plates, a joining device, and a joining structure.

Fuel economy regulations around the world are becoming stricter year by year, and automobile manufacturers are under pressure to implement systematic measures in response to requests for improved fuel economy due to regulations on carbon dioxide emissions.
Improvements in fuel efficiency include weight reduction of the vehicle body in addition to improvement of the engine and drive system, and nonferrous metal is adopted as a constituent member as a means of weight reduction. Specifically, iron-based metals such as high-tensile steel plates are used for automobile frames that require high strength, and non-ferrous metals such as aluminum alloys are used for ceilings and suspensions that may have low strength. Used. Therefore, it is necessary to join these dissimilar metal plates together.

Examples of a method for joining a plurality of stacked metal plates include mechanical joining methods such as SPR (Self-Piercing Rivet) described in Patent Document 1 and mechanical clinch bonding described in Patent Document 2. The joining by SPR has a high joining strength because a rivet is driven and joined to a metal plate as an auxiliary material, and is used for a portion requiring high strength. Mechanical clinch bonding does not require auxiliary materials because the metal plates are plastically deformed and bonded, but the bonding strength is low, and they are used for bonding and the like.

JP, 2002-174219, A Japanese Patent No. 5213028

As described above, mechanical clinch bonding does not require auxiliary materials and is more advantageous in cost than SPR, so expansion of use is desired, but bonding strength is lower than SPR. Therefore, it is necessary to improve the joining strength in order to expand the use of caulking joining.

Therefore, an object of the present invention is to provide a method of joining a plurality of metal plates with a joining strength higher than that of caulking joining and without using an auxiliary material.

According to the present invention, a plurality of metal plates are stacked and arranged in a die having a recess, and the plurality of metal plates in the recess are pressed by a punch to give plastic deformation, thereby forming a tubular joint having a side wall and a bottom. A mechanical joining step of forming a mechanical clinch joining, and an ultrasonic joining step of metallurgically joining the bottom portion by applying ultrasonic waves to the bottom portion of the joining portion formed in the mechanical joining step; And a method of joining metal plates including

Further, the present invention provides a die having a concave portion, a punch arranged to face the concave portion, a cylinder for advancing and retracting the punch in a processing direction, an ultrasonic oscillating mechanism for applying an ultrasonic wave to the punch, A control device for controlling the operation of the cylinder, and a joining device for joining a plurality of stacked metal plates, wherein the plurality of metal plates arranged in the die are pressed by the punch. A tubular joint having a side wall and a bottom is formed by giving plastic deformation, mechanical clinch joining is performed, and ultrasonic waves are applied to the bottom of the joint by the punch to metallize the bottom. The welding mechanism according to claim 1, wherein the control mechanism controls the operation of the cylinder so that the pressing force of the punch can be adjusted to different values during plastic deformation and during ultrasonic wave application.

The pressing surface of the punch in the joining device is preferably flat.

Further, the present invention is a joining structure that constitutes a joining portion of a plurality of stacked metal plates, wherein the joining portion has a tubular shape having a sidewall portion and a bottom portion, and the sidewall portion is formed by mechanical clinch joining. The joining structure is mechanically joined and the bottom portion is metallurgically joined.

It is preferable that the plurality of metal plates are composed of different kinds of metals.

The materials of the plurality of metal plates are preferably composed of ferrous metal and non-ferrous metal.

According to the joining method of the present invention, a plurality of metal plates are mechanically joined by mechanical clinch joining, and further, by metallurgically joining by applying ultrasonic waves, caulking joining is performed without using a submaterial. Can also improve the bonding strength.

It is explanatory drawing of the joining method which concerns on 1st Embodiment of this invention. It is a schematic diagram for demonstrating the joining structure of the joining part joined by the joining method of 1st Embodiment. It is explanatory drawing of the joining method which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the mechanical joining conditions in Example 1 of this invention. It is explanatory drawing of the ultrasonic bonding conditions in Example 1 of this invention. 5 is a comparison diagram before and after ultrasonic bonding in Example 1. FIG. It is a figure which shows the measuring method of joint strength (shear strength). 6 is a graph showing the relationship between the amount of ultrasonic energy input and the bonding strength. It is a cross-sectional photograph of the joining part which ultrasonically joined dissimilar metal plates.

Hereinafter, preferred embodiments of a metal plate joining method, a joining device, and a joining structure of the present invention will be described with reference to the drawings.

<First Embodiment>
A joining method according to the first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a diagram for explaining each step of the joining method according to the first embodiment. The joining method according to the first embodiment includes a mechanical joining step and an ultrasonic joining step.

In the mechanical joining step, as shown in FIG. 1A, the metal plate 101 and the metal plate 102 are arranged in a state of being stacked on the die 20 having the recessed portion, pressed by the holding plate 30, and then punched by the punch 10. Pressurize. In this way, the metal plates 101 and 102 are plastically deformed to form an interlock and mechanical clinch bonding is performed to mechanically bond the metal plates to each other.
The plurality of metal plates (101, 102) may be the same kind of metal or different kinds of metal, but when the joining method of the present invention is used in the manufacture of automobiles, as an example, a high strength steel plate and a non-ferrous steel plate which are ferrous metals. A dissimilar metal such as an aluminum-based metal plate that is a metal is used.
Here, the mechanical clinch joining means a joining form formed on the side wall portion 111 of the joining portion 110 deformed into a cylindrical shape by being pressed by the punch 10 as shown in FIG. The side wall portion 111 of the metal plate 101 disposed at the bottom has a shape that bulges outward in the radial direction on the bottom portion 112 side, which is a joining mode in which the metal plate 101 and the metal plate 102 are engaged (interlocked). ..

FIG. 2 shows a joint structure of the joint portion 110. The joint 110 is formed in a tubular shape having a side wall 111 and a bottom 112. The above-mentioned interlock is formed in the side wall portion 111. Since the bottom portion 112 has a thickness smaller than the original thickness of the metal plate 101 and the metal plate 102 when the joint is formed, ultrasonic vibrations are easily transmitted to the joint interface in the subsequent ultrasonic joining step. Therefore, even when joining metal plates having a thickness not suitable for ultrasonic bonding, ultrasonic bonding can be performed by applying the bonding method of the present invention.

In the ultrasonic bonding step, as shown in FIG. 1B, the bottom 112 of the bonding portion 110 formed on the metal plate 101 and the metal plate 102 is placed on the anvil 50A that is a jig, and the horn 40A is used. Ultrasonic waves are applied to the bottom 112 of the joint 110 (see FIG. 2 ). The ultrasonic vibration removes the oxide film and dirt from the bonding interface between the metal plates 101 and 102, and metallurgically bonds them. The pressing surface of the horn 40A and the receiving surface of the anvil 50A hold a bottom 112 (material to be processed) at the time of applying ultrasonic waves, and thus projections are formed on the entire surface. The horn 40A can be ultrasonically vibrated by an ultrasonic oscillation mechanism (not shown).

As described above, according to the joining method of the present embodiment, the joining structure of the joining portion 110 includes the mechanical joining by mechanical clinch joining at the side wall portion 111 and the metallurgical joining by applying ultrasonic waves at the bottom portion 112. It has a high bonding strength as compared with a bonded portion formed by only one of mechanical bonding and ultrasonic bonding.
In the present embodiment, an example in which two metal plates are used as the plurality of metal plates has been shown, but three or more metal plates may be joined together.

According to the joining method and the joining structure of the first embodiment described above, the following effects are obtained.

(1) In the joining method of the present invention, a plurality of metal plates 101, 102 are stacked and arranged on a die 20 having a recess, and the plurality of metal plates 101, 102 in the recess are pressed by a punch 10 to give plastic deformation. By a mechanical joining step of forming a joining portion 110 having a side wall portion 111 and a bottom portion 112 by mechanical clinch joining, and by applying ultrasonic waves to the bottom portion 112 of the joining portion 110 formed in the mechanical joining step, And an ultrasonic bonding step of metallurgically bonding the bottom portion 112. Accordingly, the joint portion 110 is not only mechanically joined at the side wall portion 111 but also metallurgically joined at the bottom portion 112, so that the joint strength can be improved. Further, even in the case of joining metal plates having a thickness not suitable for ultrasonic joining, the thickness of the bottom portion 112 in the joining portion 110 becomes thin in the mechanical joining process. Therefore, if the joining method of the present invention is applied, Ultrasonic bonding becomes possible.

(2) A joining structure that constitutes a joining portion 110 of a plurality of metal plates 101 and 102 that are stacked is provided. And the bottom portion 112 is metallurgically joined. Accordingly, the joint structure of the joint 110 according to the present invention includes not only mechanical joints but also metallurgical joints, so that joint strength can be improved.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIG.
FIG. 3 is a diagram for explaining each step of the joining method according to the second embodiment.

As shown in FIG. 3A, the bonding apparatus 1 includes a punch 10, a die 20, a holding plate 30, a cylinder 60 for moving the punch 10 back and forth according to a processing method, and an ultrasonic oscillator 70 as an ultrasonic oscillation mechanism. The punch 10 is connected to an ultrasonic oscillator 70 and is configured to vibrate ultrasonically.
In the second embodiment, first, the metal plate 101 and the metal plate 102 are arranged in a state of being stacked on the die 20 having the recessed portion and are pressed by the holding plate 30.

In the mechanical joining process, as shown in FIG. 3B, the cylinder 60 is advanced to press the metal plate 101 and the metal plate 102 with the punch 10 to plastically deform them to form an interlock and mechanical clinch joining. Then, the metal plates are mechanically joined together. As a result, a joint structure is obtained similarly to the joint portion 110 shown in FIG.

As shown in FIG. 3C, in the second embodiment, the punch 10 is used as the horn 40B for applying ultrasonic waves to the metal plate, and the die 20 is used as the anvil 50B that is a receiving jig for applying ultrasonic waves. .. In the ultrasonic bonding step, as shown in FIG. 3B, the bottom portion 112 of the bonding portion 110 formed on the metal plate 101 and the metal plate 102 is placed on the die 20 serving as the anvil 50B, and the punch serving as the horn 40B is formed. Ultrasonic waves are applied to the bottom portion 112 of the joining portion 110 via 10 (see FIG. 2) to perform metallurgical joining. As described above, by configuring the punch 10 to be capable of ultrasonic vibration, the ultrasonic bonding step can be continuously performed following the mechanical bonding step, and the productivity can be improved.
When applying ultrasonic waves, the cylinder 60 is controlled by a control mechanism (not shown) so as to reduce the pressure applied to the joint 110 of the punch 10. This is because when ultrasonic bonding is performed with the pressure applied by the punch 10 in the mechanical bonding step, the holding force of the metal plate 101 and the metal plate 102 by the punch 10 and the die 20 is too strong, and ultrasonic vibration causes an interface between the metal plates. This is because it is not transmitted to. By reducing the pressure applied to the punch 10 when applying ultrasonic waves, ultrasonic bonding can be performed with an appropriate pressure.

According to the joining method, the joining device, and the joining structure of the second embodiment described above, the following effects are exhibited in addition to the above effects (1) and (2).

(3) A joining device for joining a plurality of stacked metal plates 101, 102 of the present invention is provided with a die 20 having a recess, a punch 10 arranged so as to face the recess, and the punch 10 in the processing direction. A cylinder 60 for advancing and retreating, an ultrasonic oscillator 70 for applying ultrasonic waves to the punch 10, and a control mechanism for controlling the advancing and retreating of the cylinder 60 are provided, and a plurality of metal plates 101, 102 arranged on the die 20 are provided. , A cylindrical joint having a side wall and a bottom is formed by applying a plastic deformation by pressurizing with the punch 10, mechanical clinch joining is performed, and ultrasonic waves are applied to the bottom 112 of the joint 110 by the punch 10 (40B). By applying, the bottom part 112 is metallurgically joined, and the control mechanism controls the operation of the cylinder 60 to make the pressing force of the punch 10 (40B) different between plastic deformation and ultrasonic wave application. It should be adjustable. Thereby, since the ultrasonic bonding process can be continuously performed from the mechanical bonding process, the productivity can be improved.

(4) The pressing surface of the punch 10 (40B) was flat. As a result, even if the punch 10 used as the horn 40B for imparting ultrasonic vibration is worn, maintenance is easier as compared with the pressing surface of a general horn provided with protrusions.

Examples in which two metal plates are joined by the joining method of the present invention, comparative examples and reference examples joined by the conventional joining method will be described below with reference to FIGS. 4 to 9.

(Example 1)
Example 1 was one in which two metal plates of the same type were bonded by the bonding method described in the first embodiment of the present invention, and two metal plates of the same type were caulked and bonded only by the mechanical bonding process. It was designated as Comparative Example 2. The test materials shown in Table 1 were used as the metal plates 101 and 102. Table 1 shows the dimensions and mechanical properties of the test material, and Table 2 shows the chemical composition (mass %) of the test material.

As shown in FIG. 4, the punch 10 has a cylindrical shape with a diameter of 4.5 mm and the radius of curvature of the corners on the pressure surface side is 0.2 mm, and the depth Jm to the bottom of the recess is 1.3 mm and the recess. The mechanical bonding process was performed using the die 20 having a bottom diameter of 7.0 mm. A step, which is one step lower than the bottom, is formed between the bottom and the side wall of the recess of the die 20. The pressure load of the punch 10 was 45 kN, and the punch 10 was pushed in until the residual plate thickness ST of the bottom 112 of the joint 110 was 1.1 mm. In this way, Comparative Example 1 was obtained by performing only caulking and joining in the mechanical joining process.

Subsequently, as shown in FIG. 5A, a horn 40A having a cylindrical shape with a diameter of 3.2 mm and having a pressing surface shown in FIG. 5B and an anvil having a pressing surface shown in FIG. 5C. Table 3 shows the bottom 112 of the joint 110 formed by mechanical joining using an ultrasonic joining device (manufactured by Japan Emerson Co., Ltd.) having an ultrasonic oscillation mechanism (not shown). Ultrasonic vibration was applied under the conditions to perform metallurgical bonding, and the example 1 was obtained.

FIG. 6A shows a cross-sectional photograph of the joint in Comparative Example 1, and FIG. 6B shows a cross-sectional photograph of the joint in Example 1. In Comparative Example 1, the joint interface can be clearly seen, whereas in Example 1, it can be seen that the joint interface is ambiguous. Thus, in Example 1, it was found that the bonding interface was metallurgically bonded.

In Example 1, ultrasonic joining was performed while changing the amount of ultrasonic energy input, and the joining strength (shear strength) in the shearing direction was measured by the tensile test shown in FIG. 7. The tensile test was performed using an autograph manufactured by Shimadzu Corporation at a tensile speed of 10 mm/min. The result is shown in the graph of FIG. In the graph of FIG. 8, the shear strength measured for Comparative Example 1 is shown by a dotted line for comparison.
As shown in FIG. 8, the bonding strength of Comparative Example 1 in which only caulking bonding was performed was about 3 kN, whereas in Example 1 in which ultrasonic bonding was also performed, the bonding strength was about 4 kN, which was about 30%. It was found that the strength was improved.

(Reference example)
Next, as a reference example, an experiment was carried out to confirm whether or not ultrasonic bonding was possible between dissimilar metals. The test materials shown in Table 4 were used as the dissimilar metals. Table 4 shows the plate thickness and mechanical properties of the test material, and Table 5 shows the chemical composition of the test material.

An ultrasonic welding apparatus manufactured by Nippon Emerson Co., Ltd. was used to change the input energy of ultrasonic waves to perform ultrasonic welding on dissimilar metal plates to obtain a reference example. The horn of the ultrasonic bonding device has a shape similar to the shape of the pressing surface shown in FIG. 5A and has a pressing surface of 5 mm×10 mm. Further, the anvil of the ultrasonic bonding device has a receiving surface similar to the shape of the receiving surface shown in FIG. 5B, and has a receiving surface of 12 mm×12 mm.

FIG. 9 shows a cross-sectional photograph of the ultrasonic bonding portion of the reference example.
According to the high-magnification cross-sectional photograph of FIG. 9, it was confirmed that the joint interface between the Al alloy plate and the plated steel plate was metallurgically bonded.

Although the embodiments and examples of the metal plate joining method, the joining device, and the joining structure of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and is appropriately changed. Is possible.

10 punch 20 die
30 Presser plate 40A, 40B Horn 50A, 50B Anvil 60 Cylinder 70 Ultrasonic oscillator 101, 102 Metal plate 110 Bonding part 111 Side wall part 112 Bottom part

Claims (6)

A plurality of metal plates are stacked and arranged in a die having a recess, and the plurality of metal plates in the recess are pressed by a punch to give plastic deformation to form a tubular joint having a side wall and a bottom. Mechanical joining process of mechanical clinch joining,
By applying ultrasonic waves to the bottom portion of the joint portion formed in the mechanical joining step, an ultrasonic joining step of metallurgically joining the bottom portion,
A method for joining metal plates, including. A die having a recess,
A punch arranged to face the recess,
A cylinder that advances and retracts the punch in the processing direction,
An ultrasonic oscillating mechanism for applying ultrasonic waves to the punch,
A control device for controlling the operation of the cylinder, and a bonding device for bonding a plurality of stacked metal plates,
The plurality of metal plates arranged on the die are pressed by the punch to give a plastic deformation to form a tubular joint having a side wall and a bottom, and mechanical clinch joining is performed,
By applying ultrasonic waves to the bottom of the joint by the punch, the bottom is metallurgically joined,
The control mechanism can control the operation of the cylinder to adjust the pressing force of the punch to different values during plastic deformation and during ultrasonic wave application. The joining device according to claim 2, wherein a pressing surface of the punch is flat. A joint structure that constitutes a joint portion of a plurality of stacked metal plates,
The joint portion has a tubular shape having a side wall portion and a bottom portion,
The side wall portion is mechanically joined by mechanical clinch joining,
A joining structure in which the bottom is metallurgically joined. The joining structure according to claim 4, wherein the plurality of metal plates are made of different kinds of metals. The joint structure according to claim 5, wherein materials of the plurality of metal plates are composed of ferrous metal and non-ferrous metal.