JP2019119122A - Thermal welding device - Google Patents

Abstract

TECHNICAL PROBLEM: To provide a thermal welding device which makes constant the amount of pressurization for pressing a welding boss by improving assembly accuracy by reducing the number of components.SOLUTION: A thermal welding device is for caulking two tip end sides of a welding boss protruding from a fixed hole at the same time by passing the welding boss formed at a thermoplastic resin molded article into the fixed hole provided on a to-be-fixed object side. In the thermal welding device comprising a resistance heating element formed at the tip end of a thermal welding device chip and the thermal welding chip constituted by a cooling pipe united with the resistance heating element, a rod cylinder is arranged in coaxial with the thermal welding chip, and a piston rod of the rod cylinder is hollow, and the cooling pipe of the thermal welding chip is connected to the piston rod, and air supplied to the hollow part of the piston rod passes through the cooling pipe communicated to the piston rod to cool the resistance heating element.SELECTED DRAWING: Figure 1

Description

In the present invention, when fixing an object to be fixed to a thermoplastic resin molded product, a welding or deformation portion called a welding boss is formed in advance on a part of the thermoplastic resin molded product, and the welding boss is used as an object to be fixed The fixing object is fixed to the thermoplastic resin molded product by melting or deforming the tip end which is made to pass through the fixing hole on the side or engage with the engaging portion formed on the fixing object side by heat. The present invention relates to a heat welding apparatus for caulking.

DESCRIPTION OF RELATED ART The heat welding apparatus currently disclosed by patent document 1 is well-known as a heat welding apparatus which carries out the caulking stop of the to-be-fixed thing to a thermoplastic resin molded article (henceforth a "molded article"). This thermal welding apparatus heats the resistance heating element at the tip of the thermal welding tip to melt and heat the welding boss, and after forming the welding boss into a desired shape, supply cooling air to the cooling pipe included in the thermal welding chip to weld It is a thermal welding device that cools and solidifies the boss immediately and crimps it.

This heat welding apparatus clamps the heat welding tip 2 in which the resistance heating element 3 and the cooling pipe 5 are coaxially arranged and the cooling pipe 5 of the heat welding tip 2 as shown in FIG. An air cylinder or an electric cylinder (not shown) showing the thermal welding device 1 (lifting block) configured of the slide rail 12 and the spring 13, the stroke sensor (photoelectric sensor) 15 for detecting the operating position of the thermal welding tip 2, and the mounting base 11. It is a structure to raise and lower with.

In addition, adjustment of the strength (pressing force) of the thermal welding tip 2 pressing the welding boss is performed by applying the amount of pressure of the spring 13 with the adjuster nut 14b, and the completion of the caulking stop is lowered to the position set by the thermal welding tip 2. Is detected by the stroke sensor 15.

Moreover, in patent document 2, the joining apparatus which biases a heater chip | tip (heat welding chip | tip) with a compression coiled spring, and generates desired pressing force is disclosed. This bonding apparatus has a structure in which the elevating block is moved up and down by a motor and a ball screw, a rod connected to the heater chip is biased by a compression coil spring, and the heater chip is brought into contact with the joint to heat it.

Unexamined-Japanese-Patent No. 2010-042527 JP 2012-228700 A

However, these heat welding devices have the following problems.
The thermal welding apparatus comprises a elevating block, a spring for urging the thermal welding tip (heater chip) and the thermal welding tip in the caulking direction of the welding boss, a slide guide for sliding the thermal welding tip up and down, and a thermal Since it is comprised with a stroke sensor etc. which detect the position of a welding tip, it is necessary to assemble precisely, confirming operation of parts mutually.

In addition, since the pressing force at the time of caulking is adjusted by the amount of pressure applied by the spring, when using a plurality of heat welding tips, it was very time-consuming to make the amount of pressure applied by each spring uniform. .

Moreover, since the fixed object to be crimped to the molded product is miniaturized year by year and arranged with high density, the distance between the welding bosses to be crimped becomes narrow, and the thermal welding apparatus is miniaturized to enable welding of the narrow portion. There is a need.

Further, with the three-dimensional shaping of the molded product, the object to be fixed is often disposed on the free curved surface, and it is necessary to arrange the thermal welding device to the inclined position at a different angle or direction for each welding boss. However, since the conventional thermal welding apparatus can only perform the pressing operation by the spring, an operation cylinder for moving the thermal welding apparatus independently for each angle is required for processing in the inclination direction. And increase in the complexity of the thermal welding equipment.

In order to solve these problems according to the present invention, the invention according to claim 1 is characterized in that the welding boss formed on the thermoplastic resin molded product is passed through the fixing hole provided on the object side from the fixing hole A thermal welding apparatus for simultaneously caulking two protruding welding bosses at the front end side of the welding boss, comprising a resistance heating element formed at the tip of the heat melting apparatus tip and a cooling pipe integrated with the resistance heating element In the heat melting apparatus having the heat welding tip, a rod cylinder is disposed coaxially with the heat welding tip, a piston rod of the rod cylinder is hollow, and the cooling pipe of the heat welding tip is connected to the piston rod And the air supplied to the hollow portion of the piston rod can cool the resistance heating element by passing through the cooling pipe in communication with the piston rod. It is characterized in that formed by.

The invention according to claim 2 is characterized in that, in the heat welding apparatus according to claim 1, the heat welding tip of the heat welding apparatus is an impulse heating system.

The invention according to claim 3 is characterized in that, in the heat welding device according to any one of claims 1 or 2, the rod cylinder of the welding device is an air cylinder operated by air pressure. It is

The invention according to claim 4 is characterized in that, in the heat welding device according to any one of claims 1 to 3, the rod cylinder of the welding device is an electric cylinder operated by electric control. It is

The invention according to claim 5 is characterized in that in the heat welding apparatus according to any one of claims 1 to 4, the pressing force of the rod cylinder of the welding apparatus changes in the caulking process. It is

According to the present invention described above, the following effects can be obtained.
Since the number of parts is small, assembly is easy and assembly accuracy is also improved.
Furthermore, the variation in the amount of pressure applied to the heat-welded tip can be made constant.
Furthermore, the thermal welding apparatus can be miniaturized and installed in a narrow space.
Furthermore, the force corresponding to the formation angle of the welding boss is free, and the pressing force of the welding boss can be made constant and the size can be reduced to facilitate installation in a narrow space.
Furthermore, the dimensional accuracy is stabilized by increasing the pressing force of the welding boss at the end of the welding process.

Side view of the thermal welding device Cross sectional view of thermal welding tip and cooling pipe Conventional heat welding equipment. Explanatory drawing of the welding process by a heat welding apparatus. Conceptual diagram of pressure adjustment by multiple thermal welding devices The thermal welding apparatus of the present invention disposed at an inclined position Conventional heat welding apparatus disposed at an inclined position

The heat welding apparatus according to the present invention has a structure in which the pressing is performed by an air cylinder in which a heat welding tip of an impulse heating system and a cooling pipe of the heat welding tip and a hollow piston rod are coaxially connected.

The thermal welding tip is determined by the size and shape of the welding boss to be crimped, and the piston diameter of the air cylinder is appropriately selected according to the pressing force required for caulking the welding boss.

The heat welding apparatus will be described using FIGS. 1 to 3. FIG. 1 is a side view of the thermal welding apparatus 1, FIG. 2 is a sectional view of the thermal welding tip 2 and the cooling pipe 5, and FIG. 3 is a side view of the conventional thermal welding apparatus 1. As shown in FIG.

The heat welding apparatus 1 of FIG. 1 is composed of a heat welding tip 2 and an air cylinder 8.
The heat welding tip 2 comprises a heat generating portion 3, wires 6a and 6b, an insulating portion 4 and a cooling pipe 5. When a voltage is applied from the wires 6a and 6b, the tip 3 generates heat and the contact surface 3a of the tip 3 Is heat-melted while pressing the welding boss to perform caulking.

The contact surface 3a is basically a concave shape with a circular outer periphery, but the center of the contact surface 3a is partially convex according to the shape of the boss of the caulking stopper, or a disk-like flange is on the outer periphery Although it may be formed, the description about these shapes is omitted.

The air cylinder 8 advances and retracts the piston rod 9 penetrating the main body of the air cylinder 8 by the air pressure supplied from the air hoses 10a and 10b, and the pressure constant or variable by the air pressure from the air hose 10a in the caulking step. The heat welding tip 2 is pressed against the welding bosses.
Since the air cylinder 8 incorporates a position sensor (not shown), the position of the piston rod 9 can be detected in the forward and backward directions.

FIG. 2 is a cross-sectional view of the welding tip 2 and the piston rod 9.
The cooling pipe 5 of the welding tip 2 is coaxially joined to the piston rod 9 having a hollow structure, and the cooling air 7a supplied from the cooling hose 7 is injected through the hollow portion 9a of the piston rod 9 to the inside of the tip portion 3. . The air that has cooled the tip 3 passes through the opening 3 a and is open to the atmosphere.

FIG. 3 is a side view of the conventional heat welding apparatus 20. As shown in FIG. The conventional thermal welding apparatus 20 has a thermal welding chip 2, a slide block 12 which is attached to a cooling pipe 9 and is slid up and down, and the slide block 12 is biased to press the thermal welding chip 2 against a welding boss. , A position sensor 15 for detecting the lowered position of the slide block 12, and a lift block 11 for mounting these components.
The elevating block 11 is moved up and down with respect to the molded product by an elevating device (not shown).

The shaft 14 erected on the slide block 12 penetrates the spring 13, and the processing position is positioned by the lowering position adjusting nut 14 a provided on the upper side of the elevating block 11. The preload of the spring 13 is adjusted by a spring preload adjusting nut 14b.

The position adjustment procedure of the caulking stop in the conventional heat welding apparatus 20 determines the descent position of the heat welding apparatus 1 by a lifting device (not shown).
Set the descent limit position of the slide block 12 (welding tip 2) with the descent position adjustment nut 14a.
The position sensor 15 is set to detect the lowered position of the slide block 12.
-Measure the pressing force of heat caulking by applying a push-pull gauge (force gauge) to the tip of the welding tip 2, and set the amount of applied pressure of the spring 13 with the spring applied pressure adjusting nut 14b with 4b.
In the procedure of

However, if the lowering position of the heat welding apparatus 1 is slightly changed upward or downward in the adjustment work of the heat welding apparatus 20, the pressing force changes along with the lowering limit position of the welding tip 2. In this case, it is necessary to repeat the steps 2 to 4 described above, and the adjustment work of the thermal welding device 20 has a high degree of difficulty.

The tolerance of the spring constant of the compression coil spring used for the spring 13 is defined as 4% (first grade) to 12% (third grade) when the number of effective turns exceeds 10 in the JIS standard. Therefore, when controlled by the dimension setting of the amount of applied pressure (amount of contraction mm) of the spring 13, an error of the tolerance occurs in the pressing force against the heat welding tip 2, so the spring is measured while measuring the actual pressing force with the push-pull gauge It is necessary to adjust the pressurization amount of 13. Since a large number of heat welding tips 2 are attached to the heat welding apparatus, many steps are required to measure and adjust the pressing force.

When the dimension (mainly the diameter) of the boss 18a is changed due to a design change or the like, the heat-welded tip 2 is replaced with a dimension compatible with the boss 18a. In order to obtain an appropriate thermal caulking pressing force for the heat-welded tip 2 having different dimensions, it is necessary to reset the amount of pressure applied to the spring 13 or to change the spring constant by replacing the spring 13.

The pressing force of the caulking stop in the heat welding apparatus 1 of the present invention can be easily adjusted by the air regulator so that the air pressure supplied to the air cylinder 8 can be adjusted easily. Therefore, the lower limit position adjustment and pressing force of the conventional heat welding apparatus 20 described above It is possible to easily change the caulking condition without the need for resetting of the amount of pressure applied to the spring 13 or changing the spring constant due to replacement of the spring 13 during the change.

In addition, if the rod cylinder is an electric cylinder, the pressing force can be set constant regardless of the stroke and caulked with a fixed pressing force. Furthermore, since the electric cylinder can change the pressure depending on the processing time or working stroke by setting the program, caulking is started with a low pressing force, and the pressing force is increased according to the working time and working stroke. At the end of machining, it is also easy to stabilize the dimensional accuracy by maximizing the pressing force.

An embodiment of the crimping process according to the present invention will be described with reference to FIG. The thermal welding device 1 is lowered to a position set by a lifting device (not shown), and then the air hose 10a of the air cylinder 8 is supplied with air whose pressure is made constant by the air regulator (not shown) to operate the piston rod 9 The welding tip 2 at the tip of the rod 9 is lowered.

Electric current is supplied from the electric wires 6a and 6b at the timing when the contact surface 3a at the tip of the heat generating portion 3 of the welding tip 2 contacts the boss 18a of the molded article 18 and heat generation of the heating portion 3 of the welding tip 2 The surface 3a is softened and melted while pressing the tip of the boss 18a of the molded product 18 by the pressure of the air cylinder 8, and the tip of the boss 18a is formed into the concave shape of the contact surface 3a.

The pressing force of the welding tip 2 is determined by the diameter of the air cylinder 8 used and the air pressure, and the air pressure is set by an air regulator (not shown). For this reason, when it is desired to change the pressing force of the welding tip 2, the pressing force can be changed only by adjusting the air regulator, and there is no need to replace the spring 13 as in the prior art.

The pressure of the caulking process is reduced until the heat generation part 3 of the welding tip 2 generates heat and the temperature of the end heating part boss 18a rises, and the melting and softening of the boss 18a starts. It is desirable that the pressing force be increased to form the tip of the boss 18a into the concave shape of the contact surface 3a, and finally, the pressing force be maximized to form a crimped shape.

However, in the case of the conventional method in which the welding tip 2 is pressed by the spring 13, the welding tip 2 abuts on the tip of the boss 18a and then only the set amount of the spring 13 is contracted. The pressing force (spring constant × amount of contraction) of the welding tip 2 increases by the amount of contraction (boss processing height) from the contact position of the spring 13 and the boss 18 a melts and softens to lower the welding tip 2 Therefore, there was a problem that pressing force fell.

In addition, when the height (the caulking cost) of the welding boss 18a becomes large, the amount of contraction of the spring 13 becomes large, and there is a problem that the difference in pressing force becomes larger at the start of processing and at the end of processing. Therefore, it is necessary to use a long spring in order to reduce the change in pressing force due to the amount of contraction of the spring 13, and there is a problem that the welding device 1 becomes larger.

In the case of the pressure by the air cylinder 8 of the present invention, since the change in the pressure due to the stroke of the cylinder 8 is small, it is possible to perform the caulking with a constant pressure. In addition, it is possible to stabilize the dimensional accuracy by changing the pressing force of the cylinder 8 in the caulking process by using a pressure variable air regulator by electric control.

Next, air is supplied from the cooling hose 7 for a predetermined time, and the air passing through the hollow portion 9a of the piston rod 9 and the return pipe 5 is jetted to the tip 3 for a predetermined time, and the tip of the boss 18a via the contact surface 3a. Is solidified by cooling to complete caulking. The conduction time of the heating current is controlled by the timer, but at the same time, the position sensor of the air cylinder 8 detects the lowered position of the welding tip 2 to check whether the caulking has been completed normally.

When the caulking is completed, air is supplied to the air hose 10b of the air cylinder 8 and the piston rod 9 ascends to separate the welding tip 2 from the molded product 18, then the heat welding apparatus 1 ascends to complete the processing Do.

The pressure adjustment of the air cylinder 8 in the case of using a plurality of thermal welding devices 1 will be described with reference to FIG. FIG. 5 is a conceptual view of a device for arranging a plurality of welding devices 1 using air cylinders 8 of the same size and performing caulking. In the thermal welding apparatus 1 of the present invention, the pressure is set by one air regulator 19 and the pressing force of the welding tips 2 connected in parallel is kept constant, so that the caulking can be performed with the same pressing force.

In the conventional thermal welding apparatus 20 pressed by the spring 13, the pressing force of the welding tip 2 is measured by applying a push-pull gauge to the tip of each welding tip 2, and the amount of pressure applied by the spring 13 is the spring pressure adjusting nut 14b. It is very time consuming to set a plurality of thermal welding devices under the same pressing conditions, but according to the present invention, it is necessary to measure the pressing force at one place and set the air pressure. Well, condition setting work is greatly simplified. Moreover, since the pressing force of the welding tip 2 can be easily performed by checking the scale of the air regulator 19, it is possible to perform a stable quality caulking stop processing.

An example in which the thermal welding device 1 is mounted at the inclined position will be described with reference to FIG. FIG. 6 is a side view in which the heat welding apparatus 1 is mounted at an inclined position according to the present invention, and FIG. 7 is a side view in which the conventional heat welding apparatus 20 is mounted at an inclined position.

FIG. 6 shows a state in which the thermal welding device 1 is mounted on the inclined block 16 in order to crimp in a direction perpendicular to the inclined mounting surface of the molded article 18. The inclined block 16 on which the thermal welding device 1 is mounted is lowered by a lifting device (not shown) to approach the molded product 18 up to a preset height, and from that position the thermal welding is coaxially connected to the piston rod 9 of the air cylinder 8 The tip 2 is for caulking. The caulking process is the same as that of the first embodiment, and thus the description thereof is omitted.

Although one heat welding apparatus 1 is shown in FIG. 6, a plurality of welding bosses 18a are disposed on the surface of an actual molded product 18, and the molded product 18 has many three-dimensional shapes, so the mounting surface angle is It is not constant, and the inclination angles of the welding bosses 18a are also slightly different. For this reason, it is necessary to arrange a plurality of welding units in which the thermal welding device 1 is mounted on the inclined blocks 16 having different angles, which facilitates downsizing of the thermal welding device 1 and setting of a plurality of caulking stoppers as in the second embodiment. What you can do is important.

In the case of the conventional thermal welding apparatus 20 shown in FIG. 7 as a comparative example, the air cylinder 8 and the thermal welding apparatus 20 are mounted on the inclined block 16, and the elevating block 11 of the thermal welding apparatus 20 is inclined via the slide block 12a. The elevating block 11 and the air cylinder 8 are connected to each other by a connecting portion 17.

The operation sequence is to lower the mold 18 by a lifting device (not shown) to approach the molded product 18 up to a preset height, and from that position to the lift block 11 and the slide block 12a via the connecting portion 17 connected to the air cylinder 8. The heat welding tip 2 is lowered to the molded product 18 side. The pressing force at which the thermal welding tip 2 caulks the boss 18 a of the molded product 18 is set by the spring pressurization adjusting nut 14 b.

Compared with FIG. 6, although the action itself of the caulking stop of the heat welding tip 2 is the same, it is difficult to arrange in a complicated layout because the number of parts is large, the structure is complicated and the welding unit becomes large. . Furthermore, it is necessary to adjust the position of the thermal welding tip 2 and the pressing force with an adjustment nut in a narrow space, and many man-hours are required to set a large number of crimping conditions constant.

By using the compact thermal welding apparatus 1 of the present invention shown in FIG. 6, the degree of freedom in the arrangement of the thermal welding apparatus is increased in caulking at the inclined position, and the arrangement of dense bosses and molded articles of three-dimensional shape is achieved. It becomes possible to stop parts by caulking.

DESCRIPTION OF SYMBOLS 1 welding apparatus 2 heat welding tip 3 tip 4 insulating part 5 cooling pipe 6a, 6b electric wire 7 cooling hose 8 air cylinder 9 piston rod 10a, 10b air hose 11 lifting block 12 slide block 13 spring 14 shaft 15 position sensor 16 tilt block 17 Connection part between cylinder and elevating block 18 Molded product 19 Fixed object 20 Conventional thermal welding device 21 Air regulator

Claims (5)

A thermal welding apparatus for simultaneously welding two tip ends of welding bosses projecting from the fixing hole through a fixing hole formed on a thermoplastic resin molded product through a fixing hole provided on the object side. In the heat melting apparatus, the heat melting tip includes the resistance heating element formed at the tip of the heat melting apparatus tip and the cooling pipe integrated with the resistance heating element.
A rod cylinder is disposed coaxially with the heat welding tip,
The piston rod of this rod cylinder is hollow,
The cooling pipe of the thermal welding tip is connected to the piston rod;
The thermal welding apparatus is configured such that the air supplied to the hollow portion of the piston rod can cool the resistance heating element by passing through the cooling pipe in communication with the piston rod. The heat welding apparatus according to claim 1, wherein the heat welding tip of the heat welding apparatus is an impulse heating method. The heat welding apparatus according to any one of claims 1 and 2, wherein the rod cylinder of the heat welding apparatus is an air cylinder operated by air pressure. The heat welding apparatus according to any one of claims 1 to 3, wherein the rod cylinder of the heat welding apparatus is an electrically operated cylinder operated by electric control. The heat welding device according to any one of claims 1 to 4, wherein a pressing force of the rod cylinder of the heat welding device changes in a caulking process.

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