JPH07108607A - Method and apparatus for fixing metal boss to polyamide resin molded form - Google Patents

Abstract

PURPOSE:To obtain a method for fixing a metal boss in which processing man- hour can be reduced and productivity can be improved by emitting a high frequency wave to a metal inserted resin molded form after cooling or in a heated state to heat a resin molded part in contact with the boss to a melting temperature or higher of polyamide resin, then cooling it, and fixing the boss into a through hole of the form. CONSTITUTION:A molded form A conveyed by a belt 1 is placed on an up and down pedestal 3 by a moving arm 2, raised and moved to a position of a chuck 6 of a moving robot 5 by a fixing apparatus. The form A is cooperatively grabbed by the chuck 6, and moved to above a coil 8. Then, when a supporting base 9 is raised to support the form A, the chuck 6 is opened, the base 9 is simultaneously lowered to guide the form A into the coil 8, stationarily positioned, rotated and emitted with a high frequency wave. The robot 5 is returned onto the pedestal 3 during its period, and next similar operation is started. After the high frequency is emitted, the base 9 is again raised, the form A is grabbed by a chuck 11 of the robot, moved to above a guide route 12, and the form A is opened on the route 12 as indicated by an arrow 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a fixing device for fixing a metal boss to a polyamide resin molded product such as a gear, a wheel or a roll, or a ring-shaped or tubular product.

[0002]

Polyamide resin has self-lubricating property,
As it has excellent mechanical properties such as tensile strength and bending strength and heat resistance, it can be used as a structural member such as gears, wheels, rolls and other rotating objects used without lubrication, industrial equipment, fasteners for machine tools, etc. Widely used. A metal boss is fitted and fixed to the rotating object and the bearing portion.

As a method for fitting and fixing a metal boss to a ring-shaped product such as a polyamide resin molded product such as a polyamide resin gear, a wheel and a roll, the present applicant has previously filed Japanese Patent Application No.
No. 0-102060 (Japanese Patent Publication No. 59-22336) is proposed.

This is because when the metal boss is fitted and fixed to the polyamide resin molded product, the dry weight loss ratio of the molded product is 0.5.
% Or less and heat-expand a polyamide resin molded product having an inner diameter with a shrink-fitting margin of 0.4 to 3% with respect to the outer diameter of the metal boss, and fitting the metal boss into this to shrink-fit it, Then, the metal boss and the polyamide resin are fused by high-frequency heating.

That is, when fitting and fixing a metal boss to a polyamide resin molded product having a through hole in the center, the molded product is heated and dried to remove its volatile components, and the loss on drying rate is 0.5%. At the same time, the metal boss and the polyamide are simultaneously or continuously heated and expanded, and a metal boss is fitted into the metal boss and shrink-fitted. The resin is fused.

[0006]

However, in the case of this shrink-fitting method, when a shrink-fitting margin for fitting and fixing the metal boss is formed in the through hole formed in the polyamide resin molded product, it is heated and expanded to a predetermined extent. It is necessary to accurately provide a shrinkage allowance when cooling after cooling. For this reason, processing man-hours increase and productivity may decrease.

The present invention solves these problems and provides a method and an apparatus for fixing a metal boss to a polyamide resin molded article, which can reduce the number of processing steps and improve the productivity. .

[0008]

DISCLOSURE OF THE INVENTION The present invention for solving the above-mentioned problems is to provide at least an inner peripheral surface portion of a through hole of a polyamide resin molded article in which a through hole having a shape substantially the same as or slightly smaller than the outer shape of a metal boss is formed. After heat-softening, the heat-softened through hole is press-fitted with a metal boss having an uneven surface to form a metal-containing resin molded product, and the metal-containing resin molded product is cooled or in a heated state. Or, while rotating the coil for high frequency irradiation, this molded product is irradiated with a high frequency to heat at least the resin molded product portion in contact with the metal boss to a temperature higher than the fusion temperature of the polyamide resin, and then the resin molded product containing metal. The method is characterized by a method for fixing a metal boss to a polyamide resin molded article, in which the metal boss is cooled to fix the metal boss in the through hole of the polyamide resin molded article.

The high-frequency irradiation coil can be formed by spirally winding it and can be formed so as to cover almost the entire article to be irradiated. Further, a synthetic resin film can be applied to the surface of the high frequency irradiation coil.

The present invention also includes a mobile robot for gripping a resin-molded product containing a metal that has been moved to a predetermined position and moving it to a high-frequency irradiation coil position, and receiving the molded product from the mobile robot and coiling the molded product. A support table that is supported in a fixed state inside, a coil that radiates high frequency, and a mobile robot that receives the molded product from the support table and holds it, and guide it to the next cooling step, which is the same as or different from the above. It is also characterized in that a metal boss fixing device for a polyamide resin molded product is configured by interlocking installation.

[0011]

By heating and softening the inner peripheral surface of the through hole of the polyamide resin molded product, the metal boss can be lightly pressed and pressed into the through hole. By irradiating with high frequency while rotating, the resin molded part near the surface of the metal boss is efficiently and uniformly heated above the fusion temperature to adhere to the surface of the metal boss with unevenness and cool. As a result, the metal boss and the polyamide resin molded product are fixed to each other.

[0012]

EXAMPLE An example of the present invention will be described below. The polyamide resin molded product according to the present invention is molded by, for example, a monomer casting method, and has a through hole having a shape that is substantially the same as or slightly smaller than the outer shape of the metal boss to be fitted and fixed. The metal boss has a slight uneven shape on the surface to be joined with the resin molded product.

About 130 to 1 of the above polyamide resin molded product
It heats at 50 degreeC and heat-softens at least the inner peripheral surface part of a through-hole. If the temperature is obviously low, it will be difficult to soften, and if it is obviously high, it will be too soft, which is not preferable in terms of processing accuracy, or an additional useless heating operation will be added. In the heat-softened state, a metal boss is press-fitted into the through hole by using a pressurizing machine such as a press machine to form a metal-containing resin molded product.

In this case, if the metal boss is to be press-fitted into the through hole without being softened by heating, a considerable amount of pressure is required, but the softening by heating makes it possible to press-fit with light pressure. In addition, it is preferable that the uneven shape of the surface of the metal boss is formed as an unevenness of, for example, about 1 to 3 mm by knurling or groove processing.

Next, after the resin-containing molded product containing metal is cooled or in a heated state, the molded product or the coil for high-frequency irradiation is rotated while the high-frequency is appropriately set and irradiated, and at least the metal boss is irradiated. The inner peripheral surface portion of the resin molded product which is in contact with is heated to about 240 to 260 ° C. or higher, which is the melting temperature of the polyamide resin or higher. The above rotation makes the irradiation uniform and efficient. By the above heating, the inner peripheral surface portion of the softened molded product and the uneven portion of the metal boss are brought into close contact with each other, and both are fixed.

The high-frequency irradiation coil may be wound in a single shape so as to surround the outer periphery of the molded product, but it may be spirally wound and formed so as to cover almost the entire molded product. The irradiation efficiency can be further improved by adopting this method. In any case, the high frequency irradiation coil can be formed by combining the current-carrying portion of the coil itself and the diffusion portion such as a metal plate.

Further, it is possible to use a coil for high frequency irradiation in which the surface of the coil itself is coated with a synthetic resin film. With such a coil, even if the coil and the molded product are inadvertently contacted, the resin molded product does not melt, and it is possible to prevent the occurrence of defective products and electrical short circuits, thus ensuring work safety. It is preferable because the property can be secured.

Subsequently, the molded product is cooled to securely fix the metal boss and the polyamide resin molded product to obtain a resin molded product containing the metal boss.

An embodiment of a device for fixing the polyamide resin molded product and the metal boss by the above high frequency will be described below. FIG. 1 is a schematic front view of an example of an apparatus according to the present invention for irradiating a high frequency to fix a metal-containing resin molded product, and FIG. 2 is a schematic plan view of the same.

The metal-containing resin molded product A in which the metal boss is press-fitted by a press machine (not shown) is conveyed to a predetermined position by the conveyor belt 1. At this predetermined position, 1
A moving arm 2 is provided for moving each one to a predetermined position. The moving arm 2 is operated by an air cylinder or other arbitrary driving means, and is formed so as to sequentially hold the molded products A one by one and move the molded products A onto the elevating table 3. The elevating table 3 is horizontally installed on the upper end of the rod of the elevating device that moves up and down by any driving means such as hydraulic pressure or pneumatic pressure, and one end of the moving path 4 on which the moving arm 2 operates and a mobile robot arranged above it. It moves up and down between 5 as shown by arrow a.

The mobile robot 5 has a chuck portion 6 for gripping a molded product which is operated by an air cylinder or other arbitrary driving means, and is located between the upper part of the lifting table 3 and the upper part of the high frequency irradiation coil 8. Is installed so as to reciprocate along the rail 7 as indicated by an arrow b.

The coil 8 is fixedly installed on the side of the lifting table 3 and is connected to a high frequency generator. Inside the coil 8, a support 9 for the molded product is arranged without contact. This support base 9 has a projection 9a at the upper end that fits the molded product A, and is fixed to the upper end of the rod of an elevating device that moves up and down and rotates by a motor or other arbitrary driving means. It reciprocates with the mobile robot 5 or 10 located above, as shown by arrow c, and rotates in the coil 8 as shown by arrow d.

The mobile robot 10 is the mobile robot 5 described above.
And a chuck portion 11 which is operated by an air cylinder or other arbitrary driving means, and a rail 7 is provided between the coil 8 and a guide path 12 to a cooling device (not shown). It is installed so as to reciprocate along the arrow e. The guide path 12 may be a cooling device itself such as a water tank.

According to the above-mentioned fixing device, the molded article A conveyed by the conveyor belt 1 is placed on the elevating table 3 by the moving arm 2, and the elevating table 3 is raised to position the chuck part 6 of the mobile robot 5. Move up to. In conjunction with this, the chuck portion 6 grips the molded product A and moves the molded product A above the coil 8. Next, when the support base 9 rises to support the molded article A,
The chuck part 6 is opened, and at the same time, the support base 9 is lowered to guide the molded product A into the coil 8 so that the molded product A is fixed and rotated, and at the same time, high frequency irradiation is performed by the coil 8. In the meantime, the mobile robot 5 returns to above the lifting table 3 and starts the next operation similar to the above.

After the high-frequency irradiation, the support base 9 moves up again, and the chucked portion 11 of the mobile robot 10 which is stopped upward holds the molded product A and moves down. The mobile robot 10 moves to above the guide path 12 and opens the molded product A to the guide path 12 as indicated by an arrow f. As a matter of course, all of the above-mentioned devices are configured to be interlocked and controlled.

In the fixing device of the above embodiment, the elevating table 3 may be used as a stationary table so that the mobile robot 3 moves up and down to grip the molded article A on the stationary table. Further, similarly, the mobile robots 5 to 10 may be formed so as to move up and down with respect to the support base 9. It is preferable that the mobile robots 5 and 10 are different robots in terms of work efficiency, but it is also possible to operate both robots by one mobile robot. In this case, move b,
The operation sequence is vertical movement c, movement e, and return movement above the lifting table 3 (or stationary table). Furthermore, the support base 9
The protrusion 9a may be fitted with the molded product A and can stably support the molded product A, and may have a recess or other arbitrary configuration.

(Embodiment 1) A metal boss made of a cylindrical steel material having an outer diameter of 60 mm and a height of 30 mm whose outer peripheral surface is knurled with a pitch of 2 mm, an outer diameter of 110 mm, a height of 30 mm, and a boss hole diameter of 59.7 mm. Was prepared.

First, the molded product was heated at 140 ° C. for 1 hour. The boss hole of the molded product after heating was softened to such an extent that it could be slightly deformed. Place the metal boss in the boss hole of this heat-formed product, place it on the lower mold of a press machine of a type in which the mold descends from above, and lower the upper mold to press the metal boss into the boss hole. To form a metal-containing resin molded product. The pressure of the press was 30 kg / cm ² . In addition, when the resin molded product is not heated and a metal boss is set up in the boss hole and press-fitted as it is with the mold, 150 kg of pressure is applied.
A pressure of / cm ² was required.

The metal-containing resin molded product was placed in a copper high-frequency irradiation coil spirally wound with an inner diameter of about 130 mm and a pitch of 30 mm and having a height of about 50 mm without contacting without cooling. The copper high-frequency irradiation coil used had its outer surface insulated and coated with a urethane resin having a thickness of about 0.5 mm.

Then, while rotating the metal-containing resin molded product 5 times / minute, the same condition as in the case of the conventional technique (the technique disclosed by the applicant of the present invention), that is, a frequency of 200 KH was used.
High frequency irradiation was performed at Z, voltage 3.8 KV, and current 1.0 A. Irradiation was performed for 49 seconds. In this state, the temperature of the portion of the resin molded product in contact with the metal boss was heated to 250 to 260 ° C., which is higher than the melting temperature of the polyamide resin.

After heating, the metal-containing resin molded product was put in water and cooled to obtain a polyamide resin molded product having a metal boss fixed therein. A torque of 180 kg-m could be obtained as the metal boss fixing strength in the radial direction of this molded product.

As is apparent from the above, according to the present invention, compared with the prior art (same as above), the metal boss is heated with a predetermined pressure after heating without the need to provide a shrink fitting margin with high accuracy. Can be fitted into the boss hole, and moreover,
By heating, the metal boss fixing strength can be made higher than before, and the heating time before press-fitting the metal boss can be reduced to about 1/2 (1 hour), and the high frequency irradiation time can be significantly shortened (6
It was possible to shorten the processing time by 11 seconds compared to 0 seconds) and improve the processing cycle. Further, it has been clarified that the improvement of the metal boss fixing strength in the radial direction can be achieved and that the cost including the power cost can be reduced by changing the set value of the high frequency. Even when the molded product came into contact with the high-frequency irradiation coil, the urethane resin was coated on the outer surface, so that partial deformation such as melting did not occur.

[0033]

As described above, according to the present invention, it is not necessary to provide the resin molded product with a shrink fit allowance, and it is not necessary to heat the resin molded product to reduce its weight or to expand it by heating. The metal boss can be easily press-fitted by heating at least the inner peripheral surface of the through hole to slightly soften it. At this time, since the outer surface of the metal boss is provided with an uneven shape such as knurling, even if the dimensional accuracy of the through hole provided in the resin molded product has some fluctuation, it does not affect the fitting of the metal boss. , Easy fitting is possible. Further, it is possible to improve the fixing strength.

In addition, the heating is performed by irradiating a high frequency while rotating the metal-containing resin molded product or the high-frequency irradiation coil, so that at least the inner peripheral surface of the resin molded product in contact with the uneven metal boss is covered with the resin. Since heating is performed at the melting temperature or higher, uniform irradiation of high frequency can be performed and efficient irradiation can be performed, and the metal boss and the resin molded product can be firmly and firmly fixed by heating for a relatively short time.

Further, if the high frequency irradiation coil is wound in a spiral shape so as to cover substantially the entire molded article, the uniformity of irradiation and the irradiation efficiency are further improved.

Furthermore, if the surface of the coil for high frequency irradiation is coated with a synthetic resin film, even if the coil and the molded product are inadvertently contacted with each other, the molded product is not melted and defective products can be prevented. At the same time, electrical short circuits can be prevented, and work safety can be ensured. According to the apparatus of the present invention, the above-mentioned molded product is fixed accurately and efficiently.

[Brief description of drawings]

FIG. 1 is a schematic front view of an apparatus for fixing a metal-containing resin molded product by irradiating a high frequency, which is one embodiment according to the present invention.

FIG. 2 is a schematic plan view of FIG.

[Explanation of symbols]

 1 Conveyor Belt 2 Moving Arm 3 Lifting Table 4 Moving Path 5 Mobile Robot 6 Chuck 7 Rail 8 Coil 9 Support 10 Mobile Robot 11 Chuck 12 Guideway A Molding

Claims (4)

[Claims] 1. A polyamide resin molded article having a through hole having a shape that is substantially the same as or slightly smaller than the outer shape of a metal boss is heat-softened at least the inner peripheral surface of the through-hole, and a surface is formed in the heat-softened through-hole. A metal boss formed by forming a concave-convex shape is press-fitted to form a metal-containing resin molded product, and after cooling or in a heated state, a high frequency wave is applied to the metal-containing resin molded product or the high-frequency irradiation coil while rotating. Irradiate and heat at least the part of the resin molded product that is in contact with the metal boss to the fusion temperature of the polyamide resin or higher, and then cool the resin molded product containing the metal to make the metal boss a through hole of the polyamide resin molded product. A method for fixing a metal boss to a polyamide resin molded article, characterized in that it is fixed inside. 2. The metal boss for a polyamide resin molded article according to claim 1, wherein the high-frequency irradiation coil is formed by spirally winding it and is formed so as to cover substantially the entire article to be irradiated. Sticking method. 3. The method for fixing a metal boss to a polyamide resin molded article according to claim 1, wherein the surface of the high frequency irradiation coil is coated with a synthetic resin film. 4. A mobile robot for gripping a resin-molded product containing metal that has been moved to a predetermined position and moving it to a high-frequency irradiation coil position, and receiving the molded product from this mobile robot and placing the molded product in the coil. A configuration in which a support base that is supported by, a coil that radiates high frequency, and a mobile robot that receives and grips a molded product from the support base and guides it to the next cooling process are the same as or different from the above mobile robot. A device for fixing a metal boss to a polyamide resin molded article, comprising: