JP7066164B2 - Heat welding device - Google Patents

Description

In the present invention, when the object to be fixed is fixed to the thermoplastic resin molded product, a welded or deformed portion called a welding boss is formed in advance on a part of the thermoplastic resin molded product, and this welded boss is used as the object to be fixed. The object to be fixed is placed on the thermoplastic resin molded product by melting or deforming the tip side, which is projected through the fixing hole on the side or engaged with the engaging portion formed on the side to be fixed, by heat. It relates to a resistance heating element used in a heat welding device for caulking.

As a method for caulking an object to be fixed to a thermoplastic resin molded product, the method disclosed in Patent Document 1 is known. This method is a resistance heating element for a welding device (hereinafter referred to as "resistance heating element") that forms two heat generating parts on one heat welding tip and heats them at the same time so that the two welding bosses can be caulked at the same time. be.

In this resistance heating element, two welded chips are formed so as to project from the base surface at symmetrical positions with the center sandwiched at the tip of the chip body composed of one, and the side plate is raised from the base surface. A slit is formed so as to divide the base surface from the base surface to the back surface of the back surface of the contact surface of the welding tip from the center to the front and back, and the feeding portion for the welding tip is outside the center of the side plate. , It is formed at the front and rear symmetrical positions across the slit.
Japanese Patent No. 3899355

The power supply electric wire attached to the power supply unit for the resistance heating element used in the caulking fixing method of Patent Document 1 described above needs to stably supply a large current even when the temperature changes during heat welding, so that it is crimped. The electric wire is directly attached to the side plate by brazing as shown in FIG. 8 instead of the method of screwing with a terminal.

However, as shown in FIG. 9A, the mounting position of the electric wire may be slightly displaced from the center of the side plate due to a processing error during mounting.

Further, even if the mounting heights H of the electric wires are aligned and the mounting position is aligned with the center of the side plate, it is difficult to spread the melting allowance of the brazed braz symmetrically from the center, as shown in FIG. 9B. The range of brazing may be different on the left and right.

As a result, in the case of FIGS. 9A and 9B, a difference occurs in the heat generation temperature of the two welding chips even though the two welding chips are formed so as to project symmetrically with respect to the center. It ends up.

FIG. 11 shows an example in which the heat generation state when the mounting position of the electric wire 7 is deviated by 1 mm from the center is verified by thermal analysis (CAE). The CAE software used is Autodesk CFD. (Autodesk is a registered trademark of Autodesk Incorporated)

6a and 6b are contact surfaces for caulking, and the heat generation temperature when the position of the electric wire 7 is displaced by 1 mm to the 6a side is 215 to 220 ° C for 6a and 205 to 210 ° C for 6b according to the analysis result. The temperature difference between the two contact surfaces is about 10 ° C.

In this state, it is difficult to adjust the variation in the heating temperature of the two welding chips, and there is a problem that the variation in appearance and strength occurs when the two welding bosses are caulked at the same time.

The cause of this will be considered based on FIG. 10 (A) as to the difference in the current flowing through the heat generating portion 5 of the two welding tips 3.

FIG. 10A is a current flow (plan view) when the position of the electric wire 7 is displaced from the center.

The current flowing from the electric wire 7 branches from the side plate to the base surface 2 and flows to the electric wire 7a via the two heat generating portions 5. At this time, since the electric wire 7 is shifted to the left from the center, the electric resistance becomes R1 <R2, and a large amount of current flows to the R1 side where the electric resistance is small.

Therefore, even if the electric resistances of the two heat generating portions 5 are the same, it is considered that the calorific value of the left heat generating portion 5 (R1) increases and a temperature difference occurs.

An object of the present invention is to solve the temperature difference between the two welding chips described above, and even if there is a processing error in the wire mounting position for applying a voltage to the welding chip, the heating temperature difference does not occur between the two welding chips. It is to provide a resistance heating element capable of stable quality caulking.

In order to achieve the above object, the invention according to claim 1 is a resistance heating element for a welding device capable of simultaneously caulking two welding bosses, wherein the chip body of the resistance heating element has a rectangular base surface and the same. The side plate vertically raised from the longitudinal edge of the base surface, the sleeve plate vertically raised from the short edge of the base surface, and the symmetry with a certain interval in the longitudinal direction from the center point of the base surface of the base surface. It consists of two welding chips that are vertically projected downward from the base surface at a position and have a heat generating portion at the tip, and two feeding portions. The base surface is from the center point of the base surface to the front of the heat generating portion. The sleeve plate is divided into two by a slit extending to the center of the upper end of the sleeve plate and a slit extending from the center of the upper end of the sleeve plate to the front of the heat generating portion, and the sleeve plate is divided into two by a slit extending from the center of the upper end to the front of the heat generating portion. One of the two feeding parts is on the outside of one of the two divided sleeve plates, and the other feeding part is on the outside of the other of the two divided sleeve plates, the center point of the base surface. It is characterized in that it is formed diagonally from each other and the height from the base surface is set to be the same.

Further, the invention according to claim 2 is a resistance heating element for a welding device capable of simultaneously caulking two welding bosses, and the chip body of the resistance heating element is formed from a circular base surface and a peripheral edge of the base surface. Two welded plates that are vertically raised and are projected vertically downward from the base surface at a symmetrical position at a certain interval from the center point of the base surface of the base surface, and have a heating element at the tip. It consists of a chip and two feeding parts, and the base surface is divided into two by a slit extending from the center point of the base surface to the front of the heat generating part and a slit extending from the upper end of the sleeve plate to the front of the heat generating part. The sleeve plate is divided into two by a slit extending from the upper end to the front of the heat generating portion, and one of the two feeding portions has a feeding portion on the outside of one of the divided two feeding portions and the other. The feeding portion is formed on the outside of the other side of the sleeve plate divided into two, diagonally from the center point of the base surface and within 5 mm from the slit, and the height from the base surface is the same. It is characterized by being set.

Further, the invention according to claim 3 is a resistance heating element for a welding device capable of simultaneously caulking two welding bosses according to any one of claims 1 and 2, wherein the resistance for the welding device. The heating element is characterized in that the number of electric wires connected to the feeding portion is two or more.

According to the present invention, in a welded chip in which two welded chips are formed so as to project symmetrically across the center from the tip of the chip body, even if there is a processing error in the wire mounting position for voltage application, there are two. It is possible to provide a heat welding tip in which the current flowing through the welding tip is the same and the heat generation temperature does not vary.

It is a perspective view of a resistance heating element. It is sectional drawing of a resistance heating element. 3 views of the resistance heating element, (a) is a front view, (b) is a side view, (c) is a plan view, and (d) is a bottom view. It is sectional drawing of a resistance heating element. An embodiment in which the base surface of the resistance heating element is square. This is an example in which the base surface of the resistance heating element is round. This is an embodiment in which two electric wires are attached to the feeding portion of the resistance heating element. It is a figure of the conventional electric wire attachment example. It is a figure which shows the trouble example at the time of the conventional electric wire attachment, (A) is the state which the position of a feeding line is deviated from the center, and (B) is the state which the brazing range is different on the left and right. It is a schematic diagram of the current flow. In (A), when the position of the feeding part of the conventional resistance heating element is deviated from the center, in (B), the position L of the feeding part of the resistance heating element of the present invention is left and right. Indicates different cases. It is a contour diagram showing the heat generation state of the conventional resistance heating element by thermal analysis, and shows the temperature when the position of the power supply part is deviated by 1 mm from the center. It is a contour diagram which shows the heat generation state of the resistance heating element of this invention by thermal analysis, (A) shows the temperature when the position of an electric wire is 2mm from a slit, and (B) shows the temperature when the position of an electric wire is 3mm from a slit.

The basic form of the resistance heating element according to the present invention is that two welded chips are formed so as to protrude from the bottom surface of the chip body at intervals on the left and right, and further, from the upper end of the chip body to the heat generating portion of the welded chip. In the form in which a slit or a cavity is inserted so as to be divided into two parts in the front-rear direction, the position of the feeding portion of the + and-poles with respect to the chip body divided into two parts is based on the intermediate line between the welding bosses on the side plate. It is formed separately on the left and right, and the positions in the height direction from the base surface are set to be the same.

Next, an embodiment of the present invention will be described in detail with reference to each figure.

The first embodiment will be described in detail with reference to FIGS. 1, 2, 3 (a) to 3 (d) and FIG.

FIG. 1 is a perspective view of the resistance heating element 1, and FIG. 2 is a sectional view taken along the line AA of the resistance heating element 1. The resistance heating element 1 is composed of a chip main body 2 and two welded chips 3 that are symmetrically projected on the base surface 2a of the chip main body 2 with a certain interval between them. Slits 8 and 8a are formed so as to be divided into two from the sleeve plate 2b of the chip main body 2 to the base surface 2a and the back side of the heat generating portion 5 formed in the protruding portion 4 formed at the tip of the welded chip 3.

As a whole, the chip body 2 is divided into two parts, and the base surface 2a portion of the chip body 2 straddles the slit 8 in the front-rear direction with + and-pole pieces, and is outside the two welded chips 3. The front and back are connected by the heat generating portion 5 with the appearance of being projected from the top.

The slits 8 and 8a of the chip body 2 function as an insulating space, and the slit 8a also serves as an outlet for cooling air.

Further explaining the chip body 2 with reference to FIGS. 3A to 3D, the chip body 2 has two divided protrusions 4 and two protrusions 4 intersecting each other at the tip of the protrusions 4. A heat generating portion 5 is formed in the portion. A concave contact surface 6 is formed on the tip surface of the heat generating portion 5, and the slit 8a reaches the back side of the heat generating portion 5.

The position of the feeding portion (attaching portion of the electric wires 7 and 7a) with respect to the chip main body 2 is outside the left and right welding chips 3 on the sleeve plate 2b, and is symmetrical in a plan view on a diagonal line having an intermediate point 2c as an intersection. It is formed separately at each position, and the height from the base surface 2a is 10 mm, which are set to be the same.

In this embodiment, the height of the feeding portion from the base surface 2a is set to 10 mm, but the height is not limited to this dimension, and can be appropriately set depending on the height dimension of the chip body 2 and the mounting method of the electric wires 7 and 7a. However, the height from the base surface 2a is always the same.

Since the electric wires 7 and 7a are fixed to the feeding portion by brazing, a width of about 2 to 5 mm is required for brazing and fixing, but the wires 7 and 7a should be as close to the slit 8 as possible and the distance from the slit 8 should be two. The same is desirable for both.

In this embodiment, the mounting positions of the electric wires 7 and 7a are set to 2 mm from the slit 8 in FIG. 3 (b), but up to about 10 mm is allowed.
Explaining the arrangement of the electric wires 7 and 7a in a plan view and a bottom view in FIG. 3 (d), a point object in which the electric wires 7 and 7a are connected diagonally with the intermediate point 2c of the two welding chips 3 as the center point. It is an arrangement that becomes.

As shown in FIG. 4, the resistance heating element 1 having the above configuration has an insulating support member 10 inserted in the chip main body 2, the outside of the chip main body 2 including the electric wire 7 is covered with a cover 9, and the support The heat welding device 1 is formed by inserting the air pipe 11 through the center of the member 10 from the rear.

In this embodiment, the electric wire 7 is fixed by brazing, but the method of fixing the electric wire is not limited to this, and it goes without saying that various attachment methods such as welding to a crimp terminal or a tab can be selected.

Next, the error in the mounting position of the electric wires 7 and 7a and the heat generation balance of the welded tip 3 in this embodiment are verified.

FIG. 10B is a plan view of the arrangement of the electric wires 7 and 7a.
At this time, the electric wire 7 is arranged at a point target with the slit 8 for dividing the chip main body 2 interposed therebetween, but an error may occur in the positions L1 and L2 in the Y direction.

FIG. 12A shows the results of thermal analysis (CAE) when the mounting positions L1 and L2 of the electric wires 7 and 7a are aligned at 2 mm from the slit 8.

FIG. 12B shows heat generation analysis (CAE) when the mounting position L2 of the electric wire 7a is similarly 2 mm from the slit 8 and the mounting position L1 of the electric wire 7 is 3 mm from the slit.

According to the analysis results, when the position of L1 is 2 mm in FIG. 12 (A) and 3 mm in FIG. 12 (b), the contact surfaces 6a and 6b of the heat generating portion 5 are at 225 ° C to 227 ° C in both cases. It was confirmed that there was no difference in the heat generation temperature at the tip of the chip.

This is because, as shown in FIG. 10B, when the current from the electric wire 7 branches from the chip body 2 and flows to the electric wire 7a via the heat generating portion 5, the resistances R1 and R2 pass through the two heat generating portions 5. The difference is very small, and it is considered that there is no difference in the heat generation temperature because the currents flowing through the two heat generation units 5 are almost the same.

As described above, when the position of the conventional electric wire 7 is displaced by 1 mm, the temperature difference between the two welding chips is about 10 ° C. in the thermal analysis of FIG. 11, but according to the present invention, the position of the electric wire 7 is displaced by 1 mm. Even in this case, the temperature difference of the heat generating portion 5 does not matter, so that when the two welding bosses are caulked at the same time, the appearance and strength are less likely to vary and the quality is stable.

Further, if a large current is required, it is possible to attach a plurality of electric wires.

FIG. 7 shows a structure in which, in the first embodiment, a side plate relief portion 2e is provided on the side of the sleeve plate 2b of the chip body 2 where the electric wire 7 is not attached to prevent a short circuit, and two electric wires 7 are attached at a position close to the slit 8. Is.

By doing so, it becomes possible to shorten the heating time by passing a large current while trying to reduce the size of the resistance heating element 1, which leads to a reduction in the processing time.

In this embodiment, an example is shown in which the side plate relief portion 2e is provided and two electric wires 7 are used, but the processing of the side plate relief portion 2e is not indispensable, and the number of electric wires 7 to be attached to the chip body 2 and the mounting method are also included in this. It is not limited.

Example 3 will be described with reference to FIG.

FIG. 5 is a perspective view of the chip body 2 of the resistance heating element 1 in a square view in a plan view.

The configuration of the resistance heating element 1 is basically the same as that of the heating element having a rectangular chip body in FIG. 1, but the electric wire mounting portion for applying voltage is 2 mm from the slit 8 of the sleeve plate 2b of the chip body 2 divided into two. Therefore, the two welded chips 3 are formed at the point-to-target positions on the diagonal line with the intermediate point 2c as the intersection, and the heights from the base surface are set to be the same.

It is desirable that the electric wires 7 and 7a of the feeding portion are attached within 5 mm from the slit 8 and the distance from the slit 8 is the same in both places.

Even if an error of about 1 mm occurs in the mounting position of the electric wire 7, the current flowing from the electric wire 7 branches from the chip main body 2 and the current passing through the heat generating portion 5 becomes almost the same. The balance is maintained as in Example 1.

Example 4 will be described with reference to FIG.

FIG. 6 is a perspective view of the chip body 2 of the resistance heating element 1 in a circular or elliptical shape in a plan view.

The configuration of the resistance heating element 1 is basically the same as that of the heating element having a rectangular chip body in FIG. 1, but the electric wire mounting portion for applying voltage is 2 mm from the slit 8 of the sleeve plate 2b of the chip body 2 divided into two. Therefore, the two welded chips 3 are formed at the point-to-target positions on a diagonal line having the intermediate point 2c as the intersection, and the heights from the base surface are set to be the same.

It is desirable that the electric wires 7 and 7a of the feeding portion are attached within 5 mm from the slit 8 and the distance from the slit 8 is the same in both places.

Even if an error of about 1 mm occurs in the mounting position of the electric wire 7, the current flowing from the electric wire 7 branches from the chip main body 2 and the current passing through the heat generating portion 5 becomes almost the same. The balance is maintained in the same manner as in Examples 1 to 3.

1 Resistance heating element 2 Chip body 2a Base surface 2b Sleeve plate 2c Midpoint 2d Side plate 2e Side plate relief part 3 Welding tip 4 Protruding part 5 Heat generating part 6a, 6b Contact surface 7,7a Wire 8, 8a Slit 9 Cover 10 Insulation support Member 11 Air pipe 12 Brazing range

Claims (3)

The chip body of the resistance heating element is
With a rectangular base surface,
The side plate that rises vertically from the longitudinal edge of this base surface,
A sleeve plate that rises vertically from the short edge of the base surface,
Two welded chips that are projected vertically downward from the base surface at symmetrical positions with a certain interval in the longitudinal direction from the center point of the base surface of the base surface and have a heat generating portion at the tip.
It consists of two power supply units.
The base surface is divided into two by a slit extending from the center point of the base surface to the front of the heat generating portion and a slit extending from the center of the upper end of the sleeve plate to the front of the heat generating portion.
The sleeve plate is divided into two by a slit extending from the center of the upper end to the front of the heat generating portion.
One of the two feeding portions is located on the outside of one of the two divided sleeve plates, and the other feeding portion is on the outside of the other of the two divided sleeve plates, centered on the base surface. They are formed diagonally from the points, and the height from the base surface is set to be the same.
A resistance heating element for welding equipment that can simultaneously caulk two welding bosses. The chip body of the resistance heating element is
With a circular base surface,
The sleeve plate that rises vertically from the periphery of this base surface,
Two welded chips that are vertically projected downward from the base surface at symmetrical positions with a certain interval from the center point of the base surface of the base surface and have a heat generating portion at the tip.
It consists of two power supply units.
The base surface is divided into two by a slit extending from the center point of the base surface to the front of the heat generating portion and a slit extending from the upper end of the sleeve plate to the front of the heat generating portion.
The sleeve plate is divided into two by a slit extending from the upper end to the front of the heat generating portion.
One of the two feeding portions is located on the outside of one of the two divided sleeve plates, and the other feeding portion is on the outside of the other of the two divided sleeve plates, centered on the base surface. It is formed diagonally from a point and within 5 mm from the slit, and the height from the base surface is set to be the same.
A resistance heating element for welding equipment that can simultaneously caulk two welding bosses. The two welding bosses according to claim 1 or claim 2, wherein the resistance heating element for a welding device has two or more electric wires connected to the feeding portion. A resistance heating element for welding equipment that can be crimped at the same time.

Images