Tool and ultrasonic junction method

Abstract

To improve bond strength between dissimilar materials through ultrasonic junction.SOLUTION: A tool for ultrasonic junction is given in which: the tool contacts with a surface of one member of an object to be joined where two members are overlapped to transfer supersonic vibration so that two members are joined. The tool includes: a body part which is columnarly extended; and a carbon layer which is formed on a contact surface contacting with the object to be joined in the body part. The object to be joined is obtained by overlapping an aluminum member made of aluminum material with a resin member, and the body part is contacted with the object to be joined from the surface of the aluminum member.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a tool for ultrasonic bonding and an ultrasonic bonding method.

Background Art

[0002] Conventionally, ultrasonic bonding has been performed in which ultrasonic vibration is transmitted to a bonded body in which a plurality of members are stacked by a tool to bond a contact portion with this tool (see Patent Documents 1 and 2). Ultrasonic bonding is an advantageous bonding method in terms of cost and weight because, unlike a method of mechanically bonding members with a fastening component such as a rivet, no fastening component is required for each bonding location.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although ultrasonic bonding is currently used for bonding metal members, it is not used for bonding dissimilar materials such as resin members and metal members. This is because in ultrasonic bonding of dissimilar materials, there are differences in the properties of the materials, and there is a problem that it is difficult to sufficiently increase the bonding strength as a bonded body.

[0005] The present disclosure has been made to solve this problem, and an object thereof is to increase the bonding strength by ultrasonic bonding of dissimilar materials.

Means for Solving the Problems

[0006] The tool according to the present disclosure is an ultrasonic bonding tool for bonding two members by transmitting ultrasonic vibration in contact with the surface of one member with respect to a bonded body in which two members are stacked, and includes a main body portion extending in a columnar shape and a carbon layer formed on a contact surface that contacts the bonded body in the main body portion. The bonded body is a stack of an aluminum member formed of an aluminum material on a resin member, and the main body portion is a tool that contacts the bonded body from the surface of the aluminum member.

Advantages of the Invention

[0007] The applicant of the present application focused on the possibility that the contact state between the tool and the bonded body affects the bonding strength between the aluminum member and the resin member by ultrasonic bonding, and attempted to control this contact state. The control method is to coat the contact surface of the tool with the bonded body with another member, and the bonding strength in the case of bonding with tools coated with various materials is confirmed.

[0008] As a result, it was found that in the tool with a carbon layer formed on the contact surface, the bonding strength is significantly higher than in the case where other coatings are applied or no coating is applied. Therefore, with the tool according to the present disclosure, the bonding strength can be increased even between different materials such as an aluminum member and a resin member.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0011] (1) Overall configuration As shown in FIG. 1, the ultrasonic horn 1 extends in a columnar shape, and a bonding tip as a tool 10 for ultrasonic bonding is attached to the tip side thereof. In the present embodiment, a plurality (specifically, 8) of tools 10 are attached at equal angular intervals so as to surround the ultrasonic horn 1 around its axis, and it is used in a state where it is rotated around the axis so that any one of the tools 10 faces downward.

[0012] As shown in FIG. 2, this ultrasonic horn 1 is used to bond the resin member 110 and the aluminum member 120 at the contact location by bringing the tool 10 into contact with the surface of the aluminum member 120 and transmitting ultrasonic vibration to the bonded body 100 in which the aluminum member 120 is stacked on the resin member 110.

[0013] The bonded body 100 is arranged so that a region to be bonded is located between the anvil 2 and the tool 10, and ultrasonic vibration from the ultrasonic horn 1 is transmitted through the tool 10 in a state where the tool 10 is pressed against this region with a predetermined pressure (see arrow a in the figure). In the present embodiment, the ultrasonic horn 1 is configured to apply ultrasonic waves so that the ultrasonic horn 1 vibrates along its axial direction (see arrow b in the figure).

[0014] The resin member 110 is a sheet-like member formed of a resin material. In the present embodiment, it is formed of carbon fiber reinforced thermoplastics.

[0015] The aluminum member 120 is a sheet-like member formed of an aluminum alloy.

[0016] As shown in FIG. 3, each of the tools 10 includes a main body portion 11 that extends columnarly from the outer peripheral surface of the ultrasonic horn 1, and a carbon layer 15 formed on a contact surface 13 that contacts the object to be joined 100 in the main body portion 11. This carbon layer 15 is formed of diamond-like carbon.

[0017] Among these, the contact surface 13 is formed as the tip surface of the main body portion 11, and in a plan view of the plane formed by the stacking direction of the aluminum member 120 with respect to the resin member 110 (the vertical direction in FIGS. 2 and 3) and the vibration direction of the ultrasonic vibration transmitted to the object to be joined 100 (the left-right direction in FIGS. 2 and 3), it is a convex curved surface. As a result, the contact surface 13 has a convex shape from the ultrasonic horn 1 toward the object to be joined 100 side.

[0018] The ultrasonic bonding by the ultrasonic horn 1 having the above-described configuration is performed by the following procedure: the object to be joined 100 is disposed between the anvil 2 and the tool 10, and the ultrasonic horn 1 is vibrated with ultrasonic waves of a predetermined period while pressing this tool 10 against the object to be joined 100, and this ultrasonic vibration is transmitted to the object to be joined 100.

[0019] The applicant of the present application pressed the tool 10 against the object to be joined 100 with a force of 2400 N and transmitted ultrasonic vibrations with an amplitude of 65 to 70 μm for 1 second for joining. Then, the joining interface between the resin member 110 and the aluminum member 120 was observed with an electron microscope in the object to be joined 100. And from this electron microscope image, as shown in FIG. 4, a region (see the broken-line circle in the figure) where the aluminum material of the aluminum member 120 penetrates up to the resin member 110 side (specifically, between carbon fibers) was confirmed. It can be said that this region contributes to the improvement of the joining strength of both members.

[0020] (2) Modification Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the gist of the invention.

[0021] For example, in the above embodiment, the configuration in which the resin member 110 is formed of a carbon fiber reinforced thermoplastic resin was exemplified. However, the resin member 110 may have a configuration formed of other resin materials.

[0022] Further, in the above embodiment, the configuration in which the carbon layer 15 is formed of diamond-like carbon was exemplified. However, the carbon layer 15 may have a configuration formed of other carbon materials.

[0023] (3) Operational effects The applicant of the present application focused on the possibility that the contact state between the tool 10 and the joined body 100 affects the joining strength between the resin member 110 and the aluminum member 120 by ultrasonic joining, and attempted to control this contact state. The control method is to apply a coating by a separate member to the contact surface with the joined body 100 in the tool 10, and the joining strength in the case of joining with a tool coated with various materials is confirmed. Here, after performing ultrasonic joining under the same conditions as above, the aluminum member 120 was pulled in the direction of peeling from the joined body 100, and the tensile load at the time of actual peeling was measured as the joining strength.

[0024] As a result, it was found that in the tool 10 having the carbon layer 15 formed on the contact surface 13, the joining strength is significantly higher than in the case where other coatings are applied or no coating is applied. Specifically, in the case of a tool without a coating on the contact surface 13 or a tool with a titanium layer formed on the contact surface 13, the joining strength did not exceed 1400 N. However, in the tool 10 with the carbon layer 15 formed on the contact surface 13, the joining strength exceeds 1600 N, and a significant improvement in the joining strength has been confirmed.

[0025] From this, in the tool 10 of the above embodiment, the joining strength can be increased even between different materials such as the resin member 110 and the aluminum member 120.

[0026] Furthermore, the applicant of the present application has confirmed the bonding strength when bonding with a plurality of tools having different surface shapes of the contact surface 13 in the tool 10 in order to control the contact state with the object to be joined 100 by the tool 10. As a result, it has been found that in the tool 10 having the contact surface 13 with a convex curved surface shape, the bonding strength is significantly higher than when the contact surface 13 is a flat plane.

[0027] Specifically, in the tool 10 having the carbon layer 15 formed on the contact surface 13, when the contact surface 13 is a flat plane, the bonding strength was 1375 N. On the other hand, when the contact surface 13 is a convex curved surface, the bonding strength exceeds 1600 N, and a significant improvement in the bonding strength has been confirmed.

[0028] Thereby, with the tool 10 of the above-described embodiment, ultrasonic bonding with higher bonding strength can be realized.

Explanation of Reference Numerals

[0029] 1... Ultrasonic horn, 2... Anvil, 10... Tool, 11... Main body portion, 13... Contact surface, 15... Carbon layer, 100... Object to be joined, 110... Resin member, 120... Aluminum member.

Claims

1. An ultrasonic bonding tool for bonding two members by transmitting ultrasonic vibration in contact with one member surface to a bonded body formed by overlapping the two members, comprising: A main body portion extending in a columnar shape; A carbon layer formed on a contact surface in contact with the bonded body in the main body portion; and The bonded body is formed by overlapping an aluminum member made of an aluminum material on a resin member, The main body portion is brought into contact with the bonded body from the surface of the aluminum member, Tool.

2. In a plan view of the contact surface formed by the laminated direction of the aluminum member and the resin member and the vibration direction of the ultrasonic vibration transmitted to the bonded body, the contact surface is a convex curved surface, The tool according to claim 1.

3. When the resin member is formed of a carbon fiber reinforced thermoplastic resin, The carbon layer is formed of diamond-like carbon, The tool according to claim 1 or claim 2.

4. A bonding tip attached to an ultrasonic horn, The tool according to claim 1 or claim 2.

5. An ultrasonic bonding method for bonding members at the contact location of a tool by transmitting ultrasonic vibration to a bonded body formed by overlapping two members by means of the tool from the surface of one member, comprising: Using, as the bonded body, one formed by overlapping an aluminum member made of an aluminum material on a resin member, Using, as the tool, one provided with a main body portion extending in a columnar shape and a carbon layer formed on a contact surface in contact with the bonded body in the main body portion, Contacting the tool with the bonded body from the surface of the aluminum member to transmit ultrasonic vibration, Ultrasonic bonding method.

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