JP2003145625A - Method for connecting thermoplastic resin member and method for connecting fiber-reinforced thermoplastic resin member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a burr from occurring in the connection of a thermoplastic resin and to increase the connecting strength in the case of connecting a fiber- reinforced thermoplastic resin. SOLUTION: The method for connecting the thermoplastic resin member comprises the steps of bringing a first thermoplastic resin member 1 into contact with a second thermoplastic resin member 2, then pushing the first thermoplastic resin member 1 including the predetermined part of the surface boundary line 7a between the member 1 and the member 2 against a rotating probe 8 on the surface of the member 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining thermoplastic resin members and a method for joining fiber reinforced thermoplastic resin members.

[0002]

2. Description of the Related Art Conventionally, for joining thermoplastic resin members, energy is applied until the joining surfaces are melted by vibrating, ultrasonic waves, friction between the resin members or the like after the joining surfaces are brought into contact with each other, or by previously joining. The surface was pressed against a hot plate, energy was applied until the bonded surfaces were melted, and then the bonded surfaces were brought into contact with each other.

On the other hand, the joining of fiber reinforced resin containing fibers such as glass fiber and carbon fiber in resin has also been performed by using vibration, ultrasonic waves, friction between resin members, and hot plate. . For example, Japanese Patent Laid-Open No. 08-142
Japanese Patent Laid-Open No. 197 discloses a method of manufacturing a resin component in which a fiber-reinforced resin in which fibers are oriented toward a joint surface and a resin containing no fibers are brought into contact with each other and vibration welding is performed.

[0004]

However, vibration,
With any method such as ultrasonic waves, friction between resin members, hot plate, etc., since the joining surfaces are pressed with a certain predetermined pressure with the vicinity of the joining surfaces being melted, burrs occur at the joining part. was there. When burrs are generated, there is a problem that a step of removing the burrs is required and the cost is increased. Further, if the burr cannot be removed, the performance may be adversely affected depending on the product. For example, if the generated burr cannot be removed like the inner diameter side of the intake manifold, there is a problem that the burr reduces the fuel supply amount.

On the other hand, the fiber-reinforced resin has the following problems. It is well known that the fiber orientation affects the strength of the fiber orientation. That is, it is strong against the stress in the direction parallel to the fiber orientation direction and weak against the stress in the direction orthogonal to the fiber orientation direction. Therefore, in order to increase the bonding strength, it is desirable to make the fiber orientation direction orthogonal to the bonding surface. Therefore, in the above publication, the fibers are oriented toward the joint surface before joining. However, even if the fibers are oriented toward the bonding surface before bonding, it is necessary to press the members to be bonded together. Therefore, as shown in FIG. 7, the fibers 20 are parallel to the vibration direction during vibration welding. That is, the first resin member 22 and the second resin member 23 are oriented parallel to the joint surface 21, and the joint surface 21
Tensile strength (joint strength) in the direction orthogonal to
There is a problem that the bonding strength level is lowered to about 30%. The fiber orientation direction is the direction of the long axis of the fiber.

The present invention has solved the above-mentioned problems and provides a method for joining resin members in which burrs do not occur, or a joining method with high joining strength in joining fiber-reinforced resin.

[0007]

In order to solve the above technical problems, the technical means taken in claim 1 of the present invention (hereinafter referred to as the first technical means) is the first thermoplastic resin. After contacting the resin member and the second thermoplastic resin member,
A surface of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined part of the surface boundary line between the thermoplastic resin member and the second thermoplastic resin member is pressed against the surface portion by rotating a probe. A method for joining thermoplastic resin members is characterized by moving along a boundary line. here,
The surface boundary line is a portion of the contact portion between the first thermoplastic resin member and the second thermoplastic resin member, which is exposed on the surface.

According to the first technical means, heat generated by friction between the rotating probe and the thermoplastic resin member melts the portion of the thermoplastic resin member against which the probe is pressed, and the melted portion is the probe. Since it is pressed by, the melted resin is pressed and the occurrence of burrs can be suppressed. More specifically, the thermoplastic resin member against which the front portion of the rotating probe is pressed melts, the first thermoplastic resin member and the second thermoplastic resin member are joined, and the rear portion of the probe is pressed against. It solidifies in the part where it is. During the melting, joining, and solidification, the melted portion is held down by the probe, so the resin cannot come out to the probe side. Therefore, burrs do not occur. The front and rear of the probe are the direction in which the probe moves forward and the opposite direction. In addition, a support member that is in close contact with both thermoplastic resin members is provided on the back surface side of the thermoplastic resin member that faces the surface of the side on which the probe is pressed. The same applies to the following description.

In order to solve the above technical problems, the technical means taken in claim 2 of the present invention (hereinafter referred to as the second technical means) are the first thermoplastic resin member and the second thermoplastic resin member.
At least one of the thermoplastic resin members is made of fiber reinforced resin, and after contacting the first thermoplastic resin member and the second thermoplastic resin member, the first thermoplastic resin member and the second thermoplastic resin member
Pressing the rotating probe against the surface portions of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined portion of the surface boundary line with the thermoplastic resin member and moving the probe along the surface boundary line. And a method for joining fiber-reinforced thermoplastic resin members. Here, the surface boundary line is a portion of the contact portion between the first thermoplastic resin member and the second thermoplastic resin member that is exposed on the surface, as in the first technical means.

According to the second technical means, heat generated by friction between the rotating probe and the thermoplastic resin member melts the portion of the thermoplastic resin member against which the probe is pressed and the front portion of the probe. The orientation of the fibers in the thermoplastic resin melted by the probe is changed by the rotation of the probe, and the fibers are solidified in the rear part of the probe with the fibers oriented in a direction almost orthogonal to the contact surface of the contact part. As a result, it is possible to realize a bond having a high bonding strength.

The mechanism is inferred as follows. This will be described with reference to FIGS. FIG. 1 is a cross-sectional explanatory view of the state in which the first fiber-reinforced resin member and the second fiber-reinforced resin member before joining are in contact with each other as seen from above, and FIG. 2 is a cross-sectional explanatory view of the same state as that in FIG. 1 seen from the side. is there. FIG. 2 corresponds to the AA cross section of FIG.

The first fiber reinforced resin member 1 and the second fiber reinforced resin member 2 are members formed by injection molding in which thermoplastic resins 3 and 4 and fibers 5 and 6 are mixed. The fibers are oriented along the direction of resin flow during injection molding. In FIGS. 1 and 2, the fibers 5 and 6 are oriented in a direction orthogonal to the contact surfaces 7 of the first fiber-reinforced resin member 1 and the second fiber-reinforced resin member 2. However, since the contact surface 7 is an end portion of the first fiber-reinforced resin member 1 and the second fiber-reinforced resin member 2 at the time of molding, and is the end of the resin flow, the fibers 5a and 6a of FIGS.
As described above, it is oriented in a direction parallel to the contact surface 7.

FIG. 3 is a cross-sectional explanatory view showing a state in which the first fiber-reinforced resin member and the second fiber-reinforced resin member being joined are in contact with each other as viewed from above, and FIG. 4 is a side view showing the same state as in FIG. It is a section explanatory view of a completed portion. FIG. 4 corresponds to the BB cross section of FIG. A probe 8 rotating on the surface of the first fiber reinforced resin member 1 and the second fiber reinforced resin member 2 including a predetermined portion of the surface boundary line 7a between the first fiber reinforced resin member 1 and the second fiber reinforced resin member 2. It is pressed and moved in the D direction along the surface boundary line 7a. The surface boundary line 7a is a portion exposed on the resin surface of the contact surface 7. The rotation direction of the probe 8 is the C direction. At the front portion 8a of the probe 8, the thermoplastic resin is melted by the frictional heat generated by the rotation of the probe 8.
The molten resin is dragged by the rotational force of the probe 8 and moves along the rotational direction. Due to the movement of the molten resin, the thermoplastic resins of the first fiber reinforced resin member 1 and the second fiber reinforced resin member 2 are mixed. As a result, the first fiber-reinforced resin member 1 and the second fiber-reinforced resin member 2 are joined. When the molten resin moves in the rotation direction of the probe 8, the fibers 9a in the front portion 8a of the probe 8 move together with the molten resin. At this time, the orientation of the fiber 9a is changed by the rotational force of the probe 8 along the rotational direction of the probe 8 like the fibers 9b, 9c, and 9d, and when the resin is solidified at the rear portion 8b of the probe 8, the position is changed. Are fixed like fibers 9d. The orientation direction of the fixed fiber 9d is substantially orthogonal to the contact surface 7. As a result, the contact surface 7
The joint strength with respect to the tensile stress in the direction orthogonal to can be increased. There are fibers whose orientation direction is not orthogonal to the contact surface 7 around the resin-melted portion at the time of joining, but this does not significantly affect the joining strength. This is because it is the base material portion of the first fiber reinforced resin member 1 and the second fiber reinforced resin member 2, and is larger than the strength of the joint portion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
It will be described with reference to the drawings. FIG. 5 is a cross-sectional view of the probe used in the examples. The probe 8 is composed of a shaft portion 10 and a stirrer portion 11, and the material thereof is SKD61 (nitriding treatment). The shaft portion 10 has a cylindrical shape with a diameter of 15 mm and a length of 100 mm, and an agitator portion 11 is provided at one end in the length direction. The portion around the stirrer portion 11 of the shaft portion 10 provided with the stirrer portion 11 is a shoulder portion 12. The shoulder portion 12 is a portion that comes into contact with the resin at the time of joining. The stirrer 11 has a shape in which a hemisphere having a radius of 2 mm is provided at the tip of a cylinder having a diameter of 4 mm. The distance from the shoulder portion 12 to the tip of the hemisphere (stirring allowance) is 4.
It is 22 mm.

FIG. 6 is an explanatory view for explaining the state of the probe during joining. The shaft portion 10 of the probe 8 is held by a probe holding portion of a vertical milling machine device that rotationally drives the probe 8 (not shown). At this time, the cylindrical axis of the probe 8 is the surface 13 of the resin 13 against which the probe 8 is pressed.
The probe 8 is inclined from the axis perpendicular to a in the direction opposite to the forward direction of the probe 8 by the forward angle. In the embodiment, the advance angle is set to 0.5 °. It should be noted that the resin 13 is a representation of the two resins to be joined without distinction.

The probe 8 is rotated at 230 rpm, and the probe 8 is moved from the one end 7b to the other end 7c along the surface boundary line 7a in FIG. 3 at a processing speed of 20 mm / min. At this time, the shoulder portion 12 of the probe 8 is set to be pressed into the resin 13 to a predetermined depth from the surface 13a of the resin 13. This predetermined depth is referred to as the shoulder press-fitting depth.

In Example 1, both the first thermoplastic resin member and the second thermoplastic resin member are 100 mm × 100 m.
A 6 nylon material (1013NW8 manufactured by Ube Industries, Ltd.) having a size of m and a thickness of 5 mm was used. The sides with a thickness of 5 mm were brought into contact with each other, and the probe 8 rotating as described above was pressed along the surface boundary line 7a while joining under the condition of a shoulder press-fitting depth of 0.05 to 0.5 mm. The first thermoplastic resin member and the second thermoplastic resin member are lightly pressed in the directions in which they come into contact with each other, and are pressed from above by a spring to prevent displacement. Although not shown, the first thermoplastic resin member and the second thermoplastic resin member are provided on the back surface of the first thermoplastic resin member and the second thermoplastic resin member opposite to the surfaces on which the probes 8 are pressed. A supporting member (a metal flat plate) that is in close contact with is provided.

In Comparative Example 2, the same first thermoplastic resin member and second thermoplastic resin member as in Example 1 were used, and the applied pressure was 21 to 28 kgf / cm ² , the amplitude was 1.7 mm, and the welding margin was 1.8 mm. Then, vibration welding was performed under the condition of a frequency of 240 Hz.

After joining both Example 1 and Comparative Example 1, the joints were visually observed. In Comparative Example 1, burr was generated at the joint, but in Example 1, no burr was observed. As a result, in the joining method of the present invention, it is not necessary to remove burrs after joining, and the manufacturing cost can be reduced.

In Examples 2 to 4, glass fiber-containing 6-nylon GF30 material (manufactured by Ube Industries, Ltd .: 1015GN) was used as the first thermoplastic resin member and the second thermoplastic resin member.
KE) was used. Diameter about 11μm, length about 200μm
30% by weight of the glass fiber. The first thermoplastic resin member and the second thermoplastic resin member were joined under the same conditions as in Example 1 except for the shoulder press-fitting depth. In both the first thermoplastic resin member and the second thermoplastic resin member, the main orientation direction of the glass fiber is orthogonal to the contact surface. Example 2,
The shoulder press-fitting depth conditions of Example 3 and Example 4 are 0.25.
mm, 0.10 mm and 0.05 mm. All examples were performed 3 times. No burrs were found on all joints. After joining, the test piece was machined according to JIS K 7162 1BA (total length: 80 mm, parallel part thickness: 3.5, parallel part width: 5 mm, parallel part length: 30 m).
m, distance between marked lines: 25 mm) was cut out. The test piece is
The joining portion is cut out so that the contact surface is substantially in the middle of the length of the parallel portion and the contact surface is orthogonal to the length direction of the parallel portion, that is, the pulling direction. Using this test piece, a tensile strength test was performed at a pulling speed of 5 mm / min.

In Comparative Example 2, the first thermoplastic resin member and the second thermoplastic resin member made of the same materials as those in Examples 2 to 4 were used, and the applied pressure was 21 to 28 kgf / cm ² and the amplitude was 1.7 m.
Vibration welding was performed under the conditions of m, depth 1.8 mm, and frequency 240 Hz. In both the first thermoplastic resin member and the second thermoplastic resin member, the main orientation direction of the glass fiber is orthogonal to the contact surface. Comparative Example 2 was also performed 3 times, but in all cases, burrs were generated in the joint portion as in Comparative Example 1. After joining, test pieces were cut out in the same manner as in Examples 2 to 4 and a tensile strength test was performed under the same conditions as in Examples 2 to 4.

Next, 6 nylon GF used as the base material, that is, the first thermoplastic resin member and the second thermoplastic resin member
Test pieces similar to those in Examples 2 to 4 and Comparative Example 2 were cut out using No. 30 so that the main orientation direction of the glass fibers was parallel to the tensile direction, and a tensile strength test was performed under the same conditions as in Examples 2 to 4. It was The base material was also tested three times.

Table 1 shows the results of tensile strength tests of Examples 2 to 4, Comparative Example 2 and the base material. The relative strength (base metal strength retention rate) based on the tensile strength of each of three times, its average strength, and the strength of the base material was shown. In Comparative Example 2, the strength is reduced to about 20% of the base metal strength, but in Examples 2 to 4, the strength of 50% or more of the base metal strength can be secured. The base material strength tested here is the result of testing in the direction of the highest strength of the fiber reinforced resin. The fact that 50% or more of the strength can be secured is an excellent result in practical use. For example, even in the case of a non-oriented material in which the direction of the fibers is random, the fibers are oriented so as to be orthogonal to the contact surface at the joining portion by the mechanism described above, so that a joining strength higher than the base material strength can be realized. The shoulder depth is preferably 0.05 to 0.5 mm. If the shoulder depth is too large, the resin may be repelled at the shoulder and burr may occur. If the shoulder depth is too small, the shoulder portion cannot hold the resin and a groove is formed at the joint. As shown in Table 1, the shoulder depth is preferably 0.2.
It is preferably 5 mm or less, more preferably 0.1 mm or less.

[0024]

[Table 1] As described above, the thermoplastic resin is brought into contact with each other, and the rotating probe is pressed against the resin surface including the predetermined part of the surface boundary line and moved along the surface boundary line to realize the bonding without burr. it can. Further, in the case of the fiber reinforced resin, it is possible to prevent the occurrence of burrs and at the same time realize high strength bonding.

In the embodiment, the number of rotations of the probe is set to 23.
Although the rotation speed was 0 rpm, the rotation speed is not particularly limited as long as it is equal to or higher than the rotation speed at which the resin can be melted by friction heat. The amount of frictional heat is not unique because it depends on the shape of the stirrer, but is preferably 200 to 500 rpm in the stirrer shape of the example. Two
If it is less than 00 rpm, the calorific value is not sufficient and the resin is insufficiently melted to result in insufficient joining, and if it is more than 500 rpm, the frictional heat becomes too large, and the material may escape or soften. Foaming and oxidative decomposition are likely to occur, the surface has an uneven appearance, and the internal quality of the joint cannot be obtained. The advancing angle is also not particularly limited, but is preferably 0.5 to 1.5 °.

In Examples 2 to 4, the first thermoplastic resin member,
Although the case where both the second thermoplastic resin members are fiber reinforced resins is shown, the same effect can be obtained if either one is fiber reinforced resin.

The material, surface treatment and shape of the probe are
It may be appropriately set because it is related to the type and amount of the resin as the material to be joined, the type and amount of the reinforcing fiber, and the thickness of the joined portion. The shapes of the shaft portion, the shoulder portion, and the stirring bar portion may be appropriately set according to the application. The shaft portion and the stirrer portion may be integrated, or separate bodies may be joined together.
The stirrer extension of the stirrer part is 85
% Or less is desirable. If it is more than 85%, the resin will be melted down and the agitated resin cannot be retained.

In the embodiment, the contact surface is a flat surface, but is not particularly limited, and the cross section of the contact portion can be appropriately set such as an antiphase L type, a combination of T-shape and U-shape. Further, the shapes of the first thermoplastic resin member and the second thermoplastic resin member can be applied to various shapes such as a cylindrical shape like an intake manifold other than the flat plate.

[0029]

As described above, according to the present invention, the surfaces of the first thermoplastic resin member and the second thermoplastic resin member are brought into contact with each other after the first thermoplastic resin member and the second thermoplastic resin member are brought into contact with each other. A thermoplastic resin, characterized in that a rotating probe is pressed against the surface portions of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined portion of the boundary line and moved along the surface boundary line. At least one of the joining method of the members or the first thermoplastic resin member and the second thermoplastic resin member is made of fiber reinforced resin, and the first thermoplastic resin member and the second thermoplastic resin member are brought into contact with each other, and then the The rotating probe is pressed against the surface portions of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined portion of the surface boundary line between the first thermoplastic resin member and the second thermoplastic resin member. Along the surface border Since moving it towards the junction of the fiber-reinforced thermoplastic resin member, characterized in Te, to be prevented occurrence of burrs, in the joining of the fiber-reinforced resin bonding strength can be increased.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a state in which a first fiber-reinforced resin member and a second fiber-reinforced resin member before joining are in contact with each other as viewed from above.

FIG. 2 is a cross-sectional explanatory view of a state in which a first fiber-reinforced resin member and a second fiber-reinforced resin member before joining are in contact with each other as seen from a side surface.

FIG. 3 is an explanatory cross-sectional view of a state in which the first fiber-reinforced resin member and the second fiber-reinforced resin member being joined are in contact with each other as viewed from above.

FIG. 4 is an explanatory cross-sectional view of a joint-completed portion, viewed from the side, showing a state in which the first fiber-reinforced resin member and the second fiber-reinforced resin member being joined are in contact.

FIG. 5 is a cross-sectional view of a probe used in an example.

FIG. 6 is an explanatory diagram illustrating a state of the probe during joining.

FIG. 7 is an explanatory cross-sectional view of a vibration welded portion viewed from a side surface.

[Explanation of symbols]

1 ... First thermoplastic resin member 2 ... Second thermoplastic resin member 5, 6 ... Glass fiber (fiber) 7 ... Contact surface 7a ... surface boundary line 8 ... Probe

Continued front page    F term (reference) 4F211 AA29 AD05 AD16 AD19 TA01                       TC08 TD07 TN20 TQ13

Claims (2)

[Claims] 1. A first thermoplastic resin member and a second thermoplastic resin member after contacting the first thermoplastic resin member and the second thermoplastic resin member with each other.
Pressing the rotating probe against the surface portions of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined portion of the surface boundary line with the thermoplastic resin member and moving the probe along the surface boundary line. A method for joining thermoplastic resin members, comprising: 2. At least one of the first thermoplastic resin member and the second thermoplastic resin member is made of a fiber reinforced resin, and after contacting the first thermoplastic resin member and the second thermoplastic resin member, The rotating probe is pressed against the surface portions of the first thermoplastic resin member and the second thermoplastic resin member including a predetermined portion of the surface boundary line between the first thermoplastic resin member and the second thermoplastic resin member. A method for joining fiber-reinforced thermoplastic resin members, characterized by moving along a surface boundary line.