JP3318345B2 - Welding method for resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding resin molded articles, and more particularly to a method for applying a vibration to a joint between two molded articles made of resin, which can be matched with each other, so that frictional heat generated at the time of the vibrations causes both molded articles. TECHNICAL FIELD The present invention relates to a method for welding a resin molded product for welding a joint portion between them.

[0002]

2. Description of the Related Art Conventionally, as this type of welding method, as shown in FIG. 3, for example, as shown in FIG. 3, a resin upper case 21 and a matching resin lower case 22 are joined. There are methods that apply in cases. That is, the welding method shown in FIG.
Vibration is applied to the joint surface between the upper case 21 and the lower case 22 by the friction heat.
This is a method of melting and bonding a joint portion with the substrate.

In FIG. 3, an upper case 21 is a lower case 2
2. A molded article made of a resin that can be matched with 2, and has a box shape that opens downward, and an annular joining projection 24 that projects downward so as to surround the opening is formed on the opening end surface. You.

The lower case 22 that can be matched with the upper case 21 is a molded article made of resin and has a box shape that opens upward.
The two cases 21 and 22 cooperate with each other to form a hermetically closed space by opposing and matching the opening of the case.

[0005] The lower case 22 has an annular joint step 2 corresponding to the joint projection 24 of the upper case 21 on the opening end face thereof.
3 are formed, whereby the joining protrusion 24 and the joining step 2 are formed.
3 can be brought into contact with each other, and the contact surface between the joining projection 24 and the joining step 23 forms a joining surface between the upper case 21 and the lower case 22.

[0006] The joint surface between the upper case 21 and the lower case 22 is welded by applying vibration to the contact surface between the joint projection 24 of the upper case 21 and the joint step 23 of the lower case 22. . At this time, the upper case 21 and the lower case 2
Vibration is applied to the joint surface with the second member 2 in a horizontal direction in a state where pressure is applied from above and below, and a PV value is set particularly high.

In this case, the width e of the step 23 of the lower case 22 is set to be larger than the width b of the joining projection 24 of the upper case 21 so as to allow the amplitude of the vibration applied to the joining surface. Keep it. At the time of this vibration welding, the distal end portion of the joining projection 24 of the upper case 21 (the molten portion 2 in FIG. 3).
6) is melted by frictional heat due to vibration. At this time, it is desirable that the width b of the joining projection 24 is set to twice (b = 2a) the height a of the fusion portion 26. .

In the method of welding resin molded articles, as described above, pressure is applied to the joint surface between the upper case 21 and the lower case 22, that is, the contact surface between the joint protrusion 24 and the joint step 23. By applying vibration in the horizontal direction in this state, the joining protrusion 24 and the joining step 23 move relative to each other in a state of contact, so that friction is generated between the two 24 and 23 so that frictional heat is generated. become.

Then, the leading end (fused portion 26) of the joining projection 24 is melted by the frictional heat generated at this time, and as a result, the upper case 21 and the lower case 22 are formed along the joining step 23. Are welded in a joined state.

However, in such a conventional method for welding resin molded articles, poor welding may occur depending on the shape and size of the case and the direction in which vibration is applied.

For example, when the shape of the opening of the upper case 21 is rectangular, the shape of the joint projection 24 also becomes square. When a vibration in a direction perpendicular to the vibration direction (X direction in FIG. 3) is applied, the tip end (fused portion 26) of the joining protrusion 24 forming a side perpendicular to the vibration direction is in contact with the joining step 23. Due to the frictional force therebetween, it is impossible to follow the vibration, and it bends and swings around the root.

That is, when a portion forming a straight line is formed in the joining protrusion 24, the joining protrusion 24 has a low rigidity against a force applied in a direction perpendicular to the side thereof. When vibration is applied in a direction orthogonal to the vertical direction, the tip of the joining protrusion 24 may be easily deformed by the vibration.

Therefore, when the vibration in the X direction is given in FIG. 3, the tip of the joining projection 24 which forms a side perpendicular to the vibration direction swings synchronously in the vibration direction and is deformed. Therefore, the speed and distance of the relative movement between the joining protrusion 24 and the joining step 23 are reduced, and as a result, the friction of the contact surface between the joining protrusion 24 and the joining step 23 is insufficient, and the joining protrusion 24 Thus, the predetermined frictional heat required to melt the melted portion 26 cannot be obtained.

The present invention solves the above-mentioned problems, and when joining two molded articles made of resin together by vibration welding, the welded state of the joining portion can be improved regardless of the direction of vibration to be applied. It is an object of the present invention to provide a method for welding a resin molded product which can be made into a resin.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention solves the above-mentioned problems by providing a flange provided on the periphery of one molded product.
Between the flange and the flange provided on the periphery of the other molded product
Of resin molded products to join the parts together by vibration welding
The joint surface of the flange of the one molded product, the other
Project in the direction of the joining surface of the flange of
The tip is formed in a convex or concave molten portion,
The diameter gradually increases as the root part moves away from the molten part.
The joint projection formed on the tapered reinforcing part
And the joint surface of the flange of the other molded product
The tip of the protrusion can contact the bottom surface and
Protrusion can be vibrated in the direction perpendicular to the joining direction
And a tip of the joining protrusion is connected to the joining step.
Contact the bottom of the
And vibrates the joint protrusion in a direction perpendicular to the joint direction.
To melt the molten portion, and connect the reinforcing portion to the
It is buried in the molten resin that has flowed into the joint,
Means for integrally joining the two flanges together is adopted.

[0016]

According to the present invention, the above means are adopted.
Connect the tip of the joining protrusion of one resin molded product to the other resin molded product.
Contact the bottom surface of the joining step of
Apply pressure between the flanges of the
Vibration in the direction perpendicular to the joining direction during
As a result, frictional heat is generated between the joining protrusion and the joining step,
Due to the frictional heat of the melting part of the tip of the joining protrusion melts,
Melting of the reinforcement at the base of the joint protrusion flowing into the joint step
It is buried in resin, and both flanges are joined together
become.

Here, according to the present invention, it is possible to prevent the joining projection from bending and deforming when vibration for welding is applied.

That is, since the joining projection is reinforced by the tapered reinforcing portion formed at the base thereof, the strength of the tip of the joining projection is increased and the rigidity is improved. ing. Therefore, the joint projection is prevented from being deformed by the applied vibration due to its rigidity.

As a result of preventing the joint projection from being deformed when the vibration is applied, the direction of the applied vibration is not restricted. And a sufficient frictional heat can be obtained between them, so that the welded state of the joint portion can be improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below.

FIG. 1 is a view for explaining one embodiment of a method for welding a resin molded product according to the present invention. That is, the welding method of this tree <br/> fat moldings, the joining protrusion 4 to the flange <br/> the upper case 1 made of resin is provided, made of a resin capable conform to the upper case 1 of the lower case 2 A joining step 3 corresponding to the joining projection 4 is provided on the flange , and a pressure is applied to the joining surface between the joining projection 4 and the joining step 3.
The frictional heat between the joint surfaces by applying vibration
And the frictional heat melts the joint between them.
Is a method in which the base of the joining protrusion 4 is tapered.
The rigidity of the joint protrusion 4 is increased by providing
It is intended to increase.

In FIG. 1, an upper case 1 is a lower case 2
A resin molded article that can be consistent with, with a box-shaped opening downward, tension annularly outward in the opening
An outgoing flange is provided integrally with the lower side of this flange.
And an annular joining projection 4 projecting downward is integrally provided.
It has become.

The joining projection 4 has a tip portion that forms a fused portion 6 by forming a convex curved surface by an arc centered on the inside of the joining projection 4, and forms a fused portion 6 with the upper case 1. When the case 2 is welded, the molten portion 6 is melted so that the upper case 1 and the lower case 2 are bonded to each other.

The joining protrusion 4 is formed with a tapered reinforcing portion 5 having a width gradually increasing upward from a root portion to a molten portion 6. The reinforcing portion 5 has a tip portion ( The rigidity of the molten portion 6) is ensured.

The lower case 2 that can be matched with the upper case 1 is a molded article made of resin and has a box shape that opens upward. The opening of the lower case 2 and the opening of the upper case 1 are formed. Are opposed to each other so that the two cases 1 and 2 cooperate with each other to form a closed space therein.

The opening of the lower case 2 has an annular shape outward.
The flange that protrudes from the
Predetermined at the part corresponding to the joint protrusion 4 of the upper case 1 on the upper surface side
An annular joining step 3 having a depth and a width is provided.
ing. Then, match the upper case 1 with the lower case 2
In this case, the joining protrusions 4 of the upper case 1
Are designed to come into contact with each other.
The contact surface with the joining step 3 is between the two flanges of both cases 1 and 2.
Of the joint surface.

In order to weld the upper case 1 and the lower case 2, vibration is applied to the joint surface between the upper case 1 and the lower case 2, that is, the contact surface between the joint protrusion 4 and the joint step 3. Do. At this time, vibration is applied to the joint surface between the upper case 1 and the lower case 2 in the horizontal direction while pressure is applied from above and below, and the PV value is set particularly high.

In this case, the width e of the step 3 of the lower case 2
Is set to be larger than the width b of the fusion portion 6 of the joining protrusion 4 of the upper case 1 so as to allow the amplitude of vibration applied to the joining surface. And at the time of this vibration welding,
The melted portion 6 of the joining projection 4 of the upper case 1 is melted by vibration. At this time, the width b of the melted portion 6 is set to twice (b = 2a) the height a. It is desirable.

At this time, the maximum width d of the reinforcing portion 5 of the joining protrusion 4 is 3/2 times the width b of the molten portion 6 (d = 3/3).
2b), and the height a of the molten portion 6 is desirably set to be equal to the height c of the reinforcing portion 5 (a = c).

Next, the operation of the above will be described.

As described above, the method of welding the resin molded product is performed by joining the upper case 1 and the lower case 2 to each other.
On the contact surface between the joining projection 4 of the lower case 2 and the joining step 3 of the lower case 2,
By applying horizontal vibration while applying pressure, the joining protrusion 4 and the joining step 3 move relative to each other in contact with each other. Will occur.

Then, the molten portion 6 of the joining projection 4 is melted by the frictional heat generated at this time , and the molten resin is joined.
Flows out into the step 3 and into the molten resin at the base of the joining projection 4
Part 5 is buried between the flanges of both cases 1 and 2.
Will be integrally joined in a state of close contact.

Here, in the method for welding a resin molded product according to the present invention, poor welding does not occur regardless of the shape and size of the case and the direction in which vibration is applied.

That is, since the tapered reinforcing portion 5 is formed at the base of the joining protrusion 4, the joining protrusion 4 is reinforced by the reinforcing portion 5. That is, since the fusion portion 6 at the distal end of the joining protrusion 4 is reinforced by the reinforcing portion 5 to improve the rigidity, the rigidity of the fusion portion 6 causes the fusion with the joining protrusion 4 at the time of welding. When vibration is applied to the contact surface with the step portion 3, the vibration prevents the melted portion 6 from being bent and deformed.

Accordingly, the deformation of the joining protrusion 4 is prevented, so that when the vibration is applied, the joining protrusion 4 and the joining step 3 relatively move at a predetermined amplitude and speed. As a result, good friction is generated on the contact surface between the joining protrusion 4 and the joining step 3, and sufficient frictional heat is obtained, so that the welding of the joining portion can be performed reliably. .

In FIG. 1, when vibration is applied in a direction (X direction in FIG. 1) orthogonal to the sides of the joining projection 4, the rigidity of the joining projection is low in the prior art, Is deformed so as to oscillate about the root portion, thereby reducing the friction between the joint step portion 3 and the rigid portion 5 of the present invention. As a result, the molten portion 6 is prevented from swinging due to vibration, whereby the molten portion 6 follows the vibration, and the amplitude and speed of relative movement with the joining step 3 can be secured. It has become.

[0037] Then, the above results, without being limited by the direction of the vibration imparting, even vibrations in any direction, or the shape and size of the case be of any type,
Sufficient frictional heat can be obtained by improving the friction of the contact surface between the joining projection 4 and the joining step 3, and thereby the joint between the flange of the upper case 1 and the flange of the lower case 2 can be formed . <br/> The welding state can be improved. In addition, the upper case
The reinforcing portion 5 of the joining protrusion 4 of the
It will be buried in the molten resin that has flowed into the step 3.
Thus, the reinforcing portion 5 also functions as a core for reinforcing the joining portion.
Can increase bonding strength
become.

FIG. 2 shows a modification of the above embodiment.

FIG. 2 shows a modification of the shape of the tip of the fusion portion 6 of the joining projection 4 formed on the upper case 1 shown in FIG. Therefore, the detailed description is omitted by assigning the same reference numerals.

That is, the distal end of the fusion portion 16 of the joining protrusion 14 of the upper case 1 shown in FIG.
And a concave curved surface is formed by an arc centered on the outside. As described above, the shape of the joining protrusion 14 is not limited to the above-described one, and may be arbitrarily determined according to the size and shape of the upper case 1.

In the above embodiment and its modifications, the reinforcing portions 5 of the joining projections 4 and 14 are formed in a tapered shape. However, the shape is not limited to this. That is, the reinforcing portion 5
Reinforces the joint projections 4 and 14 to melt the tip 6
It suffices if it is formed in a shape that prevents deformation of the 16.

[0042]

According to the present invention, there is provided the above structure.
The joint protrusion provided on the joint surface of the flange of one molded product
With the tip of the part on the joint surface of the flange of the other molded product
Make contact with the bottom of the joint, and press
When the force is applied, the joint protrusion vibrates in the direction orthogonal to the joint direction.
To melt the molten part, and the reinforcing part flows out into the joint step
Immersed in molten resin
They will be joined together. In this case, the root of the joint
The base part gradually increases in diameter as it moves away from the melted part.
The rigidity of the joint projections is formed by the
Can be increased. Therefore,
When vibration is applied to the contact surface with the joint protrusion, the joint protrusion
Joining because it can prevent the molten part at the tip from being deformed
The relative displacement between the protrusion and the joining step at the specified amplitude and speed
Can be moved. As a result, the joining protrusion
Good friction at the contact surface between the steel and the joining step
Can produce sufficient frictional heat to melt the melted part.
The joint between the joint projection and the joint step
To facilitate product production
Can be done. Also, the shape and size of the resin molded product
Is no longer restricted by the
You can also increase the degree of freedom. Furthermore, reinforcement of the joint projection
Part is the molten wood that has melted and has flowed into the joining step.
Since it will be buried in the fat, the reinforcing part
Can function as a core to increase the degree of bonding
The strength can be greatly increased.

[0043]

[0044]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a method for welding a resin molded product according to the present invention.

FIG. 2 is a view showing a modification of the method of welding the resin molded product shown in FIG.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

 1, 21 ... upper case 2, 22 ... lower case 3, 23 ... joining step part 4, 14, 24 ... joining projection part 5 ... reinforcing part 6, 16, 26 ... molten part

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-50124 (JP, A) JP-A-62-78423 (JP, U) Katsuyoshi Saito, Adhesion and joining technology by internal heating method (1), Industrial Materials, Japan, Nikkan Kogyo Shimbun, August 1, 1986, Vol. 34, No. 8, p. 108-114 Kohei Tajima, Characteristics of Vibration Welding and Recent Applications, Plastic Age, Japan, Plastic Age, Inc., February 1, 1990, Vol. 36 90-2, p. 187-191 (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 65/06-65/08 B23K 20/10-20/12

Claims (1)

(57) [Claims] 1. A flange provided on a peripheral portion of one molded product.
Between the flange and the flange provided on the periphery of the other molded product
This is a method of welding resin molded products that are joined together by welding.
To the joint surface of the flange of one molded product and the other
Protrude in the direction of the joint surface of the flange of the
The end is formed into a convex or concave fused part and the root is
The tape gradually increases in diameter as the base part moves away from the molten part.
The joint projection formed on the reinforcing portion is formed integrally,
At the joint surface of the flange of the other molded product,
The end can contact the bottom surface, and
Joining stage that can vibrate in the direction perpendicular to the joining direction
Part, and the tip of the joining protrusion is provided on the bottom surface of the joining step.
Contact and apply pressure between the two flanges in this state.
By vibrating the joining protrusion in a direction perpendicular to the joining direction,
The molten portion is melted so that the reinforcing portion is in the joining step portion.
Immersed in the molten resin flowing out of the
A method for welding a resin molded product, wherein the flanges are integrally joined .