JPH0380413B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for fixing an inner package inside two resin molded articles. The present invention can be used to manufacture vacuum surge tanks, reservoir master cylinders, power steering oil tanks, canisters, and the like.

[Prior Art] As a conventional method for fixing an inner package inside two resin molded products, the following method is known.

(1) Undercut method A method in which a part of the inner envelope is fitted into a recess provided in the inner wall of the resin molded product, and then the two resin molded products are joined.

(2) Snap-fit method A concave part is provided on the inner wall of the resin molded product, and a convex part is provided on the inner envelope.
A method of fitting a concave part and a convex part using the elasticity of the inner envelope, and then joining two resin molded products.

(3) Caulking method A protrusion provided on the inner wall of the resin molded product is inserted into a hole provided in the inner envelope, and the penetrated protrusion is melted and pressed to make the inner envelope larger in area than the hole. A method of fixing and then joining two resin molded products.

(4) Adhesion method A method of gluing the inner envelope to the inner wall of the resin molding, and then joining the two resin molded products.

[Problems to be Solved by the Invention] The conventional method described above has the following problems.

(1) Undercut method This method requires an undercut part in the mold for molding the resin molded product, which causes problems in the molding process. Furthermore, it is difficult to fit the inner envelope into the recess.

(2) Snap-fit method This method, like the undercut method described above, requires an undercut portion in the mold, and has problems in forming. There is also a risk that the inner envelope may fall off due to deterioration of the elasticity of the inner envelope over time.

(3) Caulking method, adhesion method Although these methods reliably fix the inner body, the number of steps increases, leading to an increase in manufacturing costs.

Another method is simultaneous welding. This method uses a thermoplastic inner body and simultaneously melts and joins two thermoplastic resin molded products. This method does not require an increase in the number of steps, and the inclusion body is securely fixed. However, with this method, air bubbles may be introduced during welding, resulting in insufficient sealing performance and strength of the joint. Therefore, it is not suitable for things such as vacuum surge tanks that require sufficient sealing performance and sufficient strength at the joint between two bodies. Further, the material of the inner body is limited to thermoplastic resin, particularly the same material as the two resin molded products, and the use of inner bodies made of other materials is not possible.

The present invention provides a method for fixing an inner capsule that solves the above-mentioned problems.

[Means and effects for solving the problems] The inner package fixing method of the present invention includes a first opening end that is welded to a first locking portion that stops movement toward the bottom of an inner wall portion made of thermoplastic resin. a first engaging portion that engages with the first locking portion, and a first engaging portion that engages with the first locking portion;
When inserted and held in the outer shell, the inner envelope has an end surface slightly lower than the first opening end and has a second engaging portion that contacts the inner wall surface of the first outer shell, and the inner envelope is inserted into the first outer shell. and engaging the first engaging portion with the first locking portion; the first open end of the first outer shell portion and the second open end opposite to the first open end; heating the second open end of a lid-shaped second outer shell made of thermoplastic resin to at least partially melt the first and second open ends; The two open ends are brought into contact and pressed together, the first open end and the second open end are welded, a part of the molten part is pushed out inside the first and second outer shell parts, and the second open end of the inner envelope is welded. The second locking portion is formed on the end face of the second locking portion, and the inner package is fixed by the first locking portion and the second locking portion. It is characterized by the following.

The first outer shell part and the second outer shell part used in the method for fixing an inner capsule of the present invention generally have a cylindrical shape, and may have any cross section such as circular, square, or triangular. The material used is a thermoplastic resin that can be melted and bonded, such as addition polymers of vinyl compounds such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene, or polyamide, polycarbonate, polyacetal, linear polyester, and fluororesin. , thermoplastic resins such as cellulose derivatives can be used. Furthermore, a mixture of these resins with fillers such as glass fibers and inorganic fillers can also be used.

The inner wrapper used in the inner wrapper fixing method of the present invention is provided inside the first outer shell portion or the first outer shell portion and the second outer shell portion, and generally has a shape such as a plate shape or a cylindrical shape. to do. The material is not limited to thermoplastic resin, and various materials such as metal and thermosetting resin can be used.

In the inner package fixing method of the present invention, first, the inner package is inserted and held in the first locking part of the first outer shell part.

The first locking part restricts the movement of the inner package toward the bottom of the first outer shell, and the first locking part is a convex part provided on the inner wall or the bottom of the first outer shell. It can be made into a department. In this case, the inner envelope is inserted and held by the first engaging portion of the inner envelope engaging with the first locking portion. The first engaging portion is, for example, the peripheral edge of the lower surface of the plate-shaped inner envelope, and is the bottom of the cylindrical inner envelope.

One end surface of the inner envelope in the inserted and retained state needs to be slightly lower than the open end of the first outer shell. A wall portion of the first outer shell portion that is higher than one end surface of the inner envelope becomes a first locking portion by fusion bonding, which will be described later. If one end surface of the inner envelope is at the same height as the opening end of the first outer shell, or if one end surface of the inner envelope is higher, it becomes impossible to fix the inner envelope, and one end surface of the inner envelope is too low. In some cases, the inner capsule may wobble, resulting in insufficient fixation. Note that the wall portion of the first outer shell portion that is higher than one end surface of the inner envelope is a portion that becomes a melting margin, and the height thereof is preferably determined in consideration of the amount of protrusion of the first locking portion, which will be described later.

After the inner package is inserted into the first outer shell part, it is necessary to prevent it from falling off from the first open end, and the second engaging part is provided. For example, this second engaging part is locked by making the outer diameter of the inner envelope slightly larger than the inner diameter of the first outer shell part, or by making the outer peripheral surface into a tapered shape and stopping by elastic reaction force. be able to. A second outer shell portion is melt-bonded to the first outer shell portion. The second outer shell can be a lid-like member that covers the first outer shell, or a cylindrical member that has the same shape as the first outer shell. Further, a second inner package can be inserted and held inside the second outer shell. In this case, the same method as for inserting and holding the inner package into the first outer shell part can be used, in which a third locking part corresponding to the first locking part is formed in the second outer shell part, and a third locking part corresponding to the first locking part is formed in the second outer shell part. The movement toward the bottom is restricted by locking the third engaging portion of the second inner envelope, which corresponds to the first engaging portion, with the third locking portion. Then, the end surface of the second inner body is
It is desirable to make the opening slightly lower than the second opening end of the outer shell part and prevent the fourth engaging part from falling off, which corresponds to the second engaging part.

Next, the first part of the first outer shell part into which the inner envelope is inserted and held is
The open end and the second open end of the second outer shell are heated and melted. This melting may be done partially or the entire circumference of the opening end may be melted. As a method for heating and melting, a hot plate welding method, a hot air welding method, a welding method using frictional heat, an ultrasonic welding method, etc. can be used.

The molten first open end and second open end are pressed into contact with each other. At this time, the melted portion is pushed out to the outside and inside of the first and second outer shell parts, and becomes a melted burr. The greatest feature of the present invention is that the molten burr is actively utilized to fix the inner package. That is, the molten burr extruded inward protrudes along the end surface of the inner envelope, and is cooled and solidified to form the second locking portion. Therefore, the movement of the inner envelope toward the second outer shell is as follows:
The inner envelope is regulated by the second locking portion, and is sandwiched and fixed between the first locking portion and the second locking portion.
Note that when the second inner shell is inserted and held in the second outer shell, the molten burr is formed on the end face of the inner shell of the first outer shell and the end face of the second inner shell of the second outer shell. A second locking portion is formed by protruding between the first and second locking portions. The two inner bodies are thus fixed simultaneously, which is particularly efficient. In addition, when melting, by adjusting the vertical positions of the first outer shell and the second outer shell and adjusting the flow direction of the melted part due to gravity, it is possible to cover the peripheral edge of the inner envelope. The body becomes more firmly fixed.

[Effects of the Invention] According to the inner envelope fixing method of the present invention, the inner envelope is fixed at the same time when the end surfaces of two resin molded products are melted and joined. Furthermore, when a thermoplastic resin is used for the inner envelope, a portion of the inner envelope is integrated with the melted portion, further ensuring secure fixation. Therefore, the number of steps is not increased compared to the conventional method, and the inner package is securely fixed. Furthermore, a product with excellent sealing effect and strength at the joint can be obtained. Furthermore, the method for fixing the inner capsule of the present invention has excellent effects, such as the fact that any material can be used regardless of the material of the inner capsule.

[Example] (First Example) As shown in FIG. 1, the main body 10 and the lid 11 have substantially the same bottomed cylindrical shape, and are molded using polypropylene resin. The inner diameter of the main body 10 near the open end is 90 mm, and from the open end
From the 3.5mm inner part, the inner diameter becomes 87mm. Due to this difference in inner diameter, a ring-shaped step 12 is formed on the inner wall of the main body 10, going around the inner peripheral surface. In addition, the main body 10 and the lid body 1
Ring-shaped support parts 13 and 14 are formed on the outer surface of the main body 10 and the lid body 1.
It is used to support both parts when joining them.

The inner envelope 15 is a 2 mm thick steel disk manufactured by press working, and its diameter is the same as the inner diameter of the main body 10 near the open end.

Joining was performed as follows using the parts configured as described above.

First, the inner envelope 15 was held in the main body 10 by bringing it into contact with the step 12 . Then, with the main body 10 in the lower position and the lid body 11 in the upper position, the end surfaces 16 and 17 of the open ends of the two were melted and joined by hot plate welding.
The conditions were that the temperature of the hot plate was 280°C, the welding time was 30 seconds, and the main body 10 and the lid 11 were pressed in the axial direction. As a result, as shown in FIG. 2, the main body 10 and the lid 11 were melted to a depth of 1.2 mm from the open ends and protruded inwardly and outwardly, forming ring-shaped convex portions 18 and 19, respectively. The convex portion 18 covered the peripheral edge of the upper surface of the inner envelope 15, and the inner envelope 10 was sandwiched and fixed between the step 12 and the convex portion 18.

In the obtained product, the inner envelope 15 was securely fixed without play, and the sealing performance of the joint was excellent. Further, the strength of the joint was also equivalent to that of the main body 10 and the lid 11.

(Second Example) In this example, a two-stage, bottomed, substantially cylindrical main body 20 molded from 66 polyamide resin containing 30% by weight of glass fiber is used, and the same glass fiber as the main body 20 is used. A two-stage, bottomed, substantially cylindrical inner envelope 21 molded from a polyamide resin containing the above-mentioned components was inserted into each main body 20. and inclusion body 21
The outer surface of the first lower part 22 of the main body 20 is the first lower part 2 of the main body 20.
Since the outer diameter of the open end of the inner envelope 21 is slightly larger than the inner diameter of the open end of the main body 20, the inner envelope 21 is held without falling off from the main body 20. Two main bodies 20 holding the inner envelope 21 were used, and the open ends of each were melted and joined by a hot air welding method (hot air temperature: 390° C., welding time: 25 seconds). As a result, both inner envelopes 21 were securely fixed by the ring-shaped melting convex portions 24. Note that the melted convex portion 24 partially wrapped around the inner side of the inner envelope 21, and furthermore, the inner envelope 21 was partially melted, so that it was fixed more reliably.

(Third Example) A bottomed cylindrical main body 30 and a cylindrical lid 31 having a center hole 32 at the center of the bottom surface are molded from polypropylene resin containing 20% by weight of an inorganic filler. A substantially cylindrical inner envelope 33 having a substantially Ω-shaped cross section is inserted and held in the lid 31 by its own elastic reaction force. Note that the inner envelope 33 is molded from nylon 6 containing 30% by weight of glass fibers. Then, the main body 30 and the lid 31 were melted and joined by hot air welding. At this time, since the lid body 31 was placed at the bottom and the main body 30 was placed at the top, it was melted and joined.
A portion of the melt flows and solidifies so as to cover the surface of the inner envelope 31, forming a melt convex portion 34. Therefore, the inner envelope 31 was securely fixed, and the strength of the joint was also good.

[Brief explanation of drawings]

1 and 2 relate to a first embodiment of the present invention, with FIG. 1 being a sectional view showing the state before fusion bonding, and FIG. 2 being a sectional view showing the state after fusion bonding. 3 and 4 relate to a second embodiment of the present invention, with FIG. 3 being a sectional view showing the state before fusion bonding, and FIG. 4 being a sectional view showing the state after fusion bonding. 5 and 6 relate to a third embodiment of the present invention, with FIG. 5 being a sectional view showing the state before fusion bonding, and FIG. 6 being a sectional view showing the state after fusion bonding. 15, 21, 33...inclusion body, 18, 24, 3
4... Melting convex portion.

Claims (1)

[Claims] 1. A container-shaped first outer shell portion having a first locking portion for stopping movement toward the bottom on an inner wall portion made of thermoplastic resin, and a first open end to be welded; a first engaging portion that engages with the first locking portion;
When inserted and held in the outer shell, the inner envelope has an end surface slightly lower than the first opening end and has a second engaging portion that contacts the inner wall surface of the first outer shell, and the inner envelope is inserted into the first outer shell. and engaging the first engaging portion with the first locking portion; the first open end of the first outer shell portion and the second open end opposite to the first open end; heating the second open end of a lid-shaped second outer shell made of thermoplastic resin to at least partially melt the first and second open ends; The two open ends are brought into contact and pressed together, the first open end and the second open end are welded, a part of the molten part is pushed out inside the first and second outer shell parts, and the second open end of the inner envelope is welded. The second locking portion is formed on the end face of the second locking portion, and the inner package is fixed by the first locking portion and the second locking portion. A method for fixing an inclusion body, characterized by: 2. The second outer shell part is provided with a third locking part on the inner wall part that stops the movement toward the bottom, and a third engaging part that engages with the third locking part, and a third locking part that engages with the third locking part;
When inserted and held in the outer shell, the second inner envelope has an end surface slightly lower than the second opening end and has a fourth engaging part that contacts the inner wall surface of the second outer shell. The method for fixing an inner package according to claim 1, wherein the second inner package is inserted into a shell and fixed by the second locking part and the third locking part.