Method for manufacturing automotive resin parts and ultrasonic welding horn

Abstract

This reduces the cost of adhesive materials and adhesive parts used to join the outer member 11 and the inner member 12, and improves the recyclability of the resin part 10. [Solution] The method for manufacturing an automotive resin part 10, in which an outer member 11 and an inner member 12 are joined, involves inserting multiple piercing portions 24 provided at the tip of an ultrasonic welding horn 20 into the inner member 12 which is in contact with the outer member 11, and applying ultrasonic vibrations to the inner member 12 using the piercing portions 24. This joins the outer member 11 and the inner member 12 by ultrasonic welding.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a resin part for an automobile in which two members are ultrasonically welded, and an ultrasonic welding horn for ultrasonically welding two members constituting the resin part for an automobile.

Background Art

[0002] When manufacturing a resin part for an automobile composed of two members, methods for joining the two members include, for example, using an adhesive, using a double-sided adhesive tape, and using ultrasonic welding.

[0003] Patent Document 1 below describes a method for manufacturing a soundproof member (resin part) for an automobile, in which a resin base material and a resin fiber laminate made of a material different from this base material are joined by ultrasonic welding. In this manufacturing method, the tip of the vibrator for ultrasonic welding is pressed against the fiber laminate laminated on the base material to apply ultrasonic vibration, thereby joining the base material and the fiber laminate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case described in Patent Document 1, the tip surface of the vibrator has an uneven shape partitioned by lattice-shaped grooves, and at the time of ultrasonic welding, a film composed of the molten resin of the base material and the fiber laminate is formed on the vertical surface forming the depth of the groove, thereby increasing the joining strength between the base material and the fiber laminate. Therefore, it was necessary to weld the base material and the fiber laminate with high-power ultrasonic waves.

[0006] Furthermore, the soundproofing material manufactured by the manufacturing method described in Patent Document 1 is composed of a base material and a fiber aggregate of different materials. Therefore, when recycled, if it is recovered as a single unit, it will negatively affect the physical properties of the recycled product, and if the base material and the fiber aggregate are separated, the number of steps required increases. As a result, its recyclability was poor. [Means for solving the problem]

[0007] The present invention has been made to solve at least one of the above problems, and a method for manufacturing an automotive resin part according to one aspect of the present invention is a method for manufacturing an automotive resin part in which a first member and a second member are joined together, The ultrasonic welding horn is characterized by joining the first and second members by ultrasonic welding by applying ultrasonic vibrations to the second member using the protrusions, while the protrusions, which are provided at the tip of the horn, are pierced into the second member which is in contact with the first member.

[0008] According to the above configuration, since no separate adhesive material or adhesive parts are used to join the first and second members, the cost of adhesive materials and adhesive parts is reduced, and the recyclability of the resin parts can be improved. In addition, because the energy of the ultrasonic vibration is concentrated at the piercing point, the first and second members can be welded together with low-power ultrasound.

[0009] Preferably, the piercing portion reaches the joint surface of the second member and penetrates the second member while melting the second member by the application of ultrasonic vibration. According to the above configuration, when the piercing portion penetrates the second member, the molten resin of the second member flows to the joint surface side of the second member and the first member and functions as an adhesive, thereby increasing the joint strength. Furthermore, if the piercing portion that penetrates the second member does not extend beyond the joint surface of the first member, the impact on the appearance of the outer surface of the first member can be suppressed.

[0010] Preferably, a convex shape is provided on the joining surface of one of the first member and the second member, projecting toward the other, thereby creating a gap between the first member and the second member, into which the molten resin of the second member can flow. According to the above configuration, the molten resin of the second member, which functions as an adhesive, fills the void, thereby increasing the contact area between the first member, the second member, and the molten resin, and thus increasing the bonding strength.

[0011] Preferably, a recess is formed extending from the tip surface of the piercing portion toward the base end, thereby giving the piercing portion a rim end. According to the above configuration, the energy of ultrasonic vibrations can be concentrated at the contact point between the rim edge and the second member, thereby enhancing the effect of melting the second member with low-power ultrasonic waves and piercing and welding the piercing portion. Furthermore, since the molten resin of the second member, which functions as an adhesive between the first and second members, can be received in the recess, it is possible to suppress the molten resin from overflowing onto the opposite side of the joining surface of the second member, thereby contributing to improved bonding strength.

[0012] Preferably, the first member and the second member are made of the same resin material. According to the above configuration, the first and second components of the resin parts can be recovered as a single unit without being separated during the recycling process, thereby further improving recyclability.

[0013] Another aspect of the present invention is an ultrasonic welding horn used for joining a first member and a second member constituting an automotive resin part by ultrasonic welding, The tip is equipped with multiple piercing portions for applying ultrasonic vibrations while piercing the second member which is in contact with the first member, The aforementioned piercing portion is characterized by having a rim-like end, formed by the formation of a recess extending from the tip surface of the piercing portion toward the base end.

[0014] With the above configuration, the energy of the ultrasonic vibration is concentrated at the piercing point, allowing the first and second members to be welded together with low-power ultrasound. In particular, the energy of the ultrasonic vibration can be concentrated at the contact point between the rim and the second member, enhancing the effect of melting the second member with low-power ultrasound and piercing the piercing point to weld it together. Furthermore, since the molten resin of the second member, which functions as an adhesive between the first and second members, can be received in the recess, it is possible to suppress the molten resin from overflowing onto the opposite side of the joint surface of the second member, thereby contributing to improved joint strength. [Effects of the Invention]

[0015] According to the present invention, since no separate adhesive material or adhesive component is used to join the first member and the second member, the cost of adhesive materials and adhesive components can be reduced, and the recyclability of the resin component can be improved. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing an ultrasonic welding horn according to one embodiment of the present invention. [Figure 2] (A) A front view showing the ultrasonic welding horn. (B) A bottom view showing the ultrasonic welding horn. [Figure 3] (A) An explanatory cross-sectional view showing a method for manufacturing a resin part using the ultrasonic welding horn, the ultrasonic welding horn is shown in a cross-section along the line III-III in Figure 2(A). (B) A view from the direction along the line BB in Figure 3(A), showing the joint surface of the second member that abuts the first member. [Figure 4] (A) An explanatory cross-sectional view showing the manufacturing method, with an enlarged view of the main part showing the piercing portion inserted into the second member. (B) An explanatory cross-sectional view showing the manufacturing method, with an enlarged view of the main part of the resin component to which the first member and the second member are joined. [Modes for carrying out the invention]

[0017] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Among the resin parts 10 for automobiles, as shown in FIG. 4(B), there are those formed by joining two resin members. For example, in door trims, pillar trims, roof spoilers, etc., an outer member 11 (first member. Only a part is shown.) having a surface as a design surface is joined to an inner member 12 (second member. Only a part is shown.) for attaching the outer member 11 to a vehicle body panel (not shown) or the like by ultrasonic welding.

[0018] The ultrasonic welding horn 20 shown in FIG. 1 is a vibrator that can directly contact the inner member 12 joined to the outer member 11 and transmit ultrasonic vibrations, and is made of a metal such as aluminum, titanium, or iron. The ultrasonic welding horn 20 has a main body portion 21 on the base end side and an application portion 22 provided at the tip of the main body portion 21.

[0019] The main body portion 21 is connected to a booster (not shown) that converts an electrical signal from an ultrasonic oscillator (not shown) into mechanical vibrations and amplifies the vibrations. The application portion 22 transmits ultrasonic vibrations while applying a load to the inner member 12 in order to ultrasonically weld the inner member 12 to the outer member 11, and has a rectangular parallelepiped-shaped base portion 23 and a plurality of spike portions 24 provided on the front end surface 23a of the base portion 23.

[0020] The spike portion 24 penetrates into the inner member 12 while contacting the inner member 12 and transmitting ultrasonic vibrations during ultrasonic welding, and is formed in a frustum of a cone shape that tapers toward the tip. The spike portion 24 may be formed in other shapes such as a cylindrical shape, a frustum of a pyramid shape, or a prismatic shape.

[0021] As shown in FIGS. 1, 2(B), and 3(A), a concave portion 24a recessed toward the base end side is formed on the front end surface of the spike portion 24. In this embodiment, the concave portion 24a has a curved surface and may have a concave spherical surface. By forming the concave portion 24a, the spike portion 24 has a rim edge portion 24b, and this rim edge portion 24b can abut against the inner member 12.

[0022] In this embodiment, five piercing portions 24 of the same shape are arranged on the tip surface 23a of the base portion 23 in a five-dot pattern, but they may be arranged differently from those in this embodiment, and piercing portions 24 of different shapes may be arranged, and the number of piercing portions 24 may be less than five or more than five.

[0023] Next, a method for manufacturing a resin part 10 by joining an outer member 11 and an inner member 12 using ultrasonic welding with the ultrasonic welding horn 20 described above will be explained with reference to Figures 3 and 4. In this embodiment, the outer member 11 and the inner member 12 are made of the same resin material.

[0024] First, as shown in Figure 3(A), the inner member 12 is placed on top of the outer member 11 and brought into contact with it. The outer member 11 has an outer surface 11a which is the design surface, and an inner surface 11b which is the joining surface with the inner member 12.

[0025] As shown in Figures 3(A) and (B), the inner member 12 has a convex-shaped portion 13 that protrudes toward the outer member 11 on its inner surface 12a, which is the joint surface with the outer member 11. In this embodiment, multiple convex-shaped portions 13 are provided in a hemispherical shape and are arranged at equal intervals on the inner surface 12a of the inner member 12.

[0026] The convex portion 13 forms a gap 14 between the outer member 11 and the inner member 12. In this embodiment, the convex portion 13 is formed on the inner surface 12a of the inner member 12, but the gap 14 may also be formed by providing the convex portion 13 on the inner surface 11b of the outer member 11.

[0027] As shown in Figure 3(A), the protruding portion 24 of the ultrasonic welding horn 20 is pressed against the outer surface 12b of the inner member 12 while being pressed toward the outer member 11. Next, an ultrasonic oscillator (not shown) is activated to transmit ultrasonic vibrations to the inner member 12 via the protruding portion 24 of the ultrasonic welding horn 20. The energy of the ultrasonic vibrations is concentrated at the contact point between the rim end 24b of the protruding portion 24 and the inner member 12, causing the inner member 12 to melt and the protruding portion 24 to penetrate the inner member 12.

[0028] As shown in Figure 4(A), the piercing portion 24 is inserted into the inner member 12, and ultrasonic vibrations are applied to the inner member 12, melting the inner member 12 and creating a hole in it, reaching the inner surface 12a of the inner member 12. As a result, the piercing portion 24 penetrates the inner member 12, and the molten resin 12c of the inner member 12 flows into the void 14 and fills the void 14. In this embodiment, the piercing portion 24 is inserted into the inner member 12 so as not to exceed the inner surface 11b of the outer member 11.

[0029] The molten resin 12c of the inner member 12 that flows to the joining surface side of the outer member 11 and the inner member 12 functions as an adhesive, and by adhering tightly to the outer member 11 and the inner member 12, the outer member 11 and the inner member 12 are joined together as shown in Figure 4(B), and the resin part 10 is manufactured.

[0030] In particular, the molten resin 12c of the inner member 12 fills the gap 14, increasing the contact area between the outer member 11 and the inner member 12, thereby increasing the bonding strength.

[0031] Furthermore, as shown in Figure 4(A), by receiving the molten resin 12c of the inner member 12 into the recess 24a of the piercing portion 24, it is possible to suppress the molten resin 12c from overflowing to the outer surface 12b of the inner member 12, thereby contributing to improved bonding strength.

[0032] Furthermore, by melting the inner member 12 and creating a hole, the piercing portion 24 that penetrates the inner member 12 does not exceed the inner surface 11b of the outer member 11, thereby suppressing the impact on the outer surface 11a of the outer member 11, which is the design surface.

[0033] According to the above embodiment, since no other adhesive material or adhesive parts such as double-sided adhesive tape are used to join the outer member 11 and the inner member 12, the cost of adhesive materials and adhesive parts can be reduced, and the recyclability of the resin part 10 can be improved.

[0034] In particular, because the outer member 11 and the inner member 12 are made of the same resin material, the resin part 10 can be recovered as a whole without separating the outer member 11 and the inner member 12 during recycling, and this does not adversely affect the physical properties of the recycled product. Therefore, the recyclability of the resin part 10 can be further improved.

[0035] Furthermore, because the ultrasonic vibration energy is concentrated at the piercing portion 24, the outer member 11 and the inner member 12 can be welded together with low-power ultrasonic waves. In particular, the ultrasonic vibration energy can be concentrated at the contact point between the rim end 24b of the piercing portion 24 and the inner member 12, thereby enhancing the effect of melting the inner member 12 with low-power ultrasonic waves and piercing and welding it with the piercing portion 24.

[0036] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be adopted without departing from the spirit of the invention. In the above embodiment, the resin part 10 was manufactured by joining two members, the outer member 11 and the inner member 12, by ultrasonic welding. However, the two members constituting the resin part 10 are not limited to the outer member and the inner member, but may be any other two members. It is not necessary to provide the convex-shaped portion 13 on the inner surface 11b of the outer member 11 and the inner surface 12a of the inner member 12. The piercing portion 24 that penetrates the inner member 12 may extend beyond the inner surface 11b of the outer member 11. [Industrial applicability]

[0037] The present invention can be applied to a method for manufacturing an automotive resin part in which two members are ultrasonically welded together, and to an ultrasonic welding horn for ultrasonically welding two members constituting an automotive resin part. [Explanation of symbols]

[0038] 10 Resin part, 11 Outer member (first member), 11a Outer surface of outer member (design surface), 11b Inner surface of outer member (joint surface), 12 Inner member (second member), 12a Inner surface of inner member (joint surface), 12b Outer surface of inner member, 12c Molten resin of inner member, 13 Convex shape, 14 Gap, 20 Ultrasonic welding horn, 21 Main body, 22 Application part, 23 Base of application part, 23a Tip surface of base, 24 Piercing part, 24a Recess, 24b Rim end

Claims

1. A method for manufacturing an automotive resin part in which a first member and a second member are joined together, A method for manufacturing an automotive resin part, characterized in that the protrusions provided at the tip of an ultrasonic welding horn are pierced into the second member which is in contact with the first member, and ultrasonic vibrations are applied to the second member by the protrusions, thereby joining the first member and the second member by ultrasonic welding.

2. A method for manufacturing an automotive resin part according to claim 1, A method for manufacturing an automotive resin part, characterized in that the piercing portion melts the second member by applying ultrasonic vibrations, reaches the joint surface of the second member, and penetrates the second member.

3. A method for manufacturing an automotive resin part according to claim 2, A convex shape is provided on the joining surface of one of the first member and the second member, projecting toward the other, thereby creating a gap between the first member and the second member. A method for manufacturing an automotive resin part, characterized in that the molten resin of the second member can flow into the above-mentioned void.

4. A method for manufacturing an automotive resin part according to any one of claims 1 to 3, A method for manufacturing an automotive resin part, characterized in that a recess is formed extending from the tip surface of the piercing portion toward the base end, thereby giving the piercing portion a rim.

5. A method for manufacturing an automotive resin part according to any one of claims 1 to 3, A method for manufacturing an automotive resin part, characterized in that the first member and the second member are made of the same resin material.

6. An ultrasonic welding horn used for joining a first member and a second member constituting an automotive resin part by ultrasonic welding, The tip is provided with multiple piercing portions for applying ultrasonic vibrations while piercing the second member which is in contact with the first member, An ultrasonic welding horn characterized in that the piercing portion has a mouth-edge end, formed by the formation of a recess extending from the tip surface of the piercing portion toward the base end.

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