JP7586103B2 - Crimping device - Google Patents

Description

The present invention relates to a crimping device and a method for manufacturing molded products by crimping.

Turret punch presses that punch and process metal plates are conventionally known.
The punching press disclosed in Patent Document 1 moves a ram to cooperate with a punch and a die to perform punching on a workpiece. This press is provided with a punch position adjustment device that forms a convex portion on the head of the punch and moves a regulator plate having a hole that fits into the convex portion to regulate the movement stroke of the punch.
This punch position adjustment device regulates the amount of movement of the punch via a regulator plate and changes the feed clearance of the punch depending on the thickness and material of the workpiece.

Japanese Patent Application Publication No. 9-192755

According to the punching press of Patent Document 1, a punch position adjustment device that makes the regulator plate movable is driven to regulate the movement stroke of the punch. The punch position adjustment device is operated according to the thickness, material, etc. of the workpiece to regulate the movement stroke of the punch, making it possible to adjust the feed clearance.

This type of punching press requires a punch position adjustment device in addition to the punch drive device to regulate the punch movement stroke during punching, making the device complex and large-sized. In addition, the punching process is performed on the work by punching.

This invention is similar to Patent Document 1 in that it uses punching, but instead of punching the workpiece, it uses a fixing member corresponding to the workpiece and the object to be fixed by crimping, and the problem it is trying to solve is different from that of Patent Document 1.

The object of the present invention is to provide a crimping device and a method for manufacturing a molded product by crimping that prevents damage to the workpiece caused by the approach of the workpiece to the tip of the punch when the protrusion of the fixing member is inserted into the hole of the fixed object and the boss portion formed by crushing the protrusion from the top side is used to connect the fixing member and the fixed object.

The crimping device according to the first aspect of the present invention is a crimping device for crimping and fixing a fixing member (2) made of resin having a convex portion (4) to a fixed object (3) having a hole ( 6) into which the convex portion is inserted,
A frame (23);
a punch holder (26) that is movable up and down relative to the frame;
a punch (10) attached to the punch holder and having a pressing portion (17) at a tip thereof capable of pressing the convex portion of the fixing member;
a workpiece upper surface stopper (40) mechanically coupled to the punch holder;
The workpiece upper surface stopper has an inner wall (50) facing the tip of the punch via a gap, and an abutment surface (48) that can abut against an upper surface (33) of the object to be fixed on the protruding side of the convex portion when the convex portion of the fixing member is inserted into the hole of the object to be fixed, and prevents damage to the object to be fixed from occurring when the pressing portion approaches the upper surface ,
The abutment surface of the workpiece top surface stopper is maintained at a level equal to or spaced apart from the top surface of the fixed object to such an extent that no damage such as burrs is caused to the fixed object when the tip of the pressing portion approaches the top surface of the fixed object .

The manufacturing method of the molded product according to the second invention of the present invention is a manufacturing method of a molded product by crimping and includes the steps of: carrying in a workpiece (1) with a hole (6) of a fixed object (3) inserted into a convex portion (4) of a fixing member (2); abutting a pressing portion (17) of a solid cylindrical punch (10) against the top surface (5) of the convex portion of the fixing member to start applying pressure; abutting a workpiece top surface (33) with a workpiece top stopper (40) after pressure application is started so as to restrict the pressing portion of the punch from biting into the workpiece before the pressing portion of the punch abuts against the workpiece top surface; releasing the operation of applying pressure to the pressing portion against the workpiece after the abutment; and moving to an operation of moving the punch and the workpiece top surface stopper away from the workpiece.

The manufacturing method of the molded product according to the third invention of the present invention is a manufacturing method of a molded product by heat crimping, and includes the steps of: carrying in a workpiece (1) with a hole (6) of a fixed object (3) inserted into a convex portion (4) of a fixing member (2); abutting a pressing portion (17) of a heated solid cylindrical punch (10) against the top surface of the convex portion of the fixing member to start applying pressure; abutting a workpiece top surface stopper (40) against the workpiece top surface (33) after pressure application has started so as to restrict the pressing portion from biting into the workpiece before the pressing portion of the punch abuts against the workpiece top surface; terminating the heat crimping operation after abutment; releasing the operation of applying pressure to the workpiece with the pressing portion after completion; and transitioning to an operation of moving the punch and the workpiece top surface stopper away from the workpiece.

According to the crimping device of the first aspect of the present invention, after crimping begins, the tip of the punch descends and the top surface of the convex portion is pressed. At this time, the abutment surface of the workpiece top surface stopper, which is mechanically connected to the punch holder, abuts against the workpiece top surface of the object to which the workpiece is to be fixed.
As a result, when the crimping device is operating and the tip of the punch approaches the workpiece, the abutment surface (lower surface) of the workpiece upper surface stopper, which is mechanically connected to the punch holder, abuts against the upper surface of the workpiece before the tip of the pressing portion of the punch tip comes into contact with the upper surface of the workpiece.
Therefore, the punch can be lowered by the stroke amount required for crimping. The punch will not bite into the workpiece, regardless of unevenness in the dimensions of the workpiece or pallet.

Even if the height of the workpiece top surface relative to the crimping device is uneven, the position of the descending end of the tip of the punch will be constant relative to the workpiece top surface. This makes it possible to prevent damage such as burrs from occurring during crimping.

1 is a front view of a crimping device according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a tip portion of a punch of the crimping device according to the first embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a workpiece upper surface stopper of the crimping device according to the first embodiment of the present invention. 1 is an enlarged schematic cross-sectional view of a main portion of a crimping device according to a first embodiment of the present invention; FIG. 2 is a perspective view of a workpiece upper surface stopper according to the first embodiment of the present invention. 3A and 3B are schematic cross-sectional views showing the operation of a main part of the crimping device according to the first embodiment of the present invention, in which FIG. 3A is a schematic cross-sectional view before pressing, and FIG. 3B is a schematic cross-sectional view after pressing. 5A to 5C are schematic explanatory views showing the operation steps of the first embodiment of the present invention. FIG. 8 is an enlarged schematic explanatory diagram of a portion VIII in FIG. 7B . FIG. 8 is an enlarged schematic explanatory diagram of part IX in FIG. 7(C). FIG. 10 is an explanatory diagram illustrating the generation of burrs in a crimping device according to a comparative example.

Below, the crimping device and the method of manufacturing a molded product according to several embodiments of the present invention will be described with reference to the drawings. Note that the same reference numerals are used to designate substantially the same components in several embodiments, and the description will be omitted.

First Embodiment
A crimping device and a method for manufacturing a molded product according to a first embodiment of the present invention will be described with reference to FIGS.

The crimping device of this embodiment is a thermal crimping device that manufactures molded products by thermal crimping. This thermal crimping device uses an electric heating punch.

As shown in FIG. 1, the thermal crimping device 20 has a frame 23 that can be moved up and down by a drive unit 22 attached to a base 21. A linear guide 25 is provided so as to be movable relative to a guide rail 24 formed on the side of the frame 23, and a punch holder 26 is fixed to the linear guide 25.

The punch holder 26 is biased in the downward direction as shown in FIG. 1 by a compression coil spring 31 relative to the frame 23, and its downward movement is restricted by a stopper 32.
The punch 10 having a solid cylindrical shape is fixed to a punch holder 26. The tip portion 12 of the punch 10 fixes the workpiece 1 to the fixing member 2 and the object 3 by thermal crimping through thermal welding, as shown in FIG.

Although a workpiece is not shown in FIG. 1, the punch holder 26 is formed of a holder body 261 having a portion for fixing the punch 10, and a punch holder extension portion 27 that extends downward from another portion of the holder body 261 in the axial direction of the punch 10 near the punch 10.

The punch holder extension 27 is formed by extending in the direction in which the tip 12 of the punch 10 presses the workpiece. One end 41 of the workpiece upper surface stopper 40 is fixed to the lower end of the punch holder extension 27.

As shown in FIG. 2, the tip 12 of the punch 10 has an annular tapered surface 13 on the outer wall and an annular tapered surface 14 on the inner wall that widens toward the tip. The bottom surface of the tip 12 of the punch 10 has a concave curved surface 15. This curved surface 15 of the punch 10 can press against the top surface of the protrusion 3 of the fixed member 1. The pressing portion 17 formed on the tip 12 of the punch 10 forms an annular protrusion 16 on the tip 12 of the punch 10. The annular protrusion 16 is formed by the annular tapered surface 13 of the outer wall and the annular tapered surface 14 of the inner wall.

The workpiece upper surface stopper 40 has one end 41 joined to the lower end of the punch holder extension 27, and the other end 42 having a notch 43 as shown in Fig. 5. In the space formed by this notch 43, the tip 12 of the punch 10 shown in Fig. 2 is positioned as shown in Figs. 1 and 4.
The workpiece upper surface stopper 40 has an inner wall 50 that faces a part of the tip portion 12 of the punch 10 with a gap therebetween.

The inner wall 50 faces a part of the outer wall of the tip portion 12 of the punch 10 via a gap, and as shown in Figures 3 and 4, forms a notch 43, and has a large diameter portion 44 having a large arc-shaped surface, a slope portion 45, a small diameter portion 46 having a small arc-shaped surface, and a radially inward protruding portion 47.
The abutting portion 47 has a radially inward protruding portion 471, and the lower surface forms the abutting surface 48. The inner wall 50 faces the outer wall of the tip portion 12 of the punch 10 with a gap therebetween.

The outer surface of the abutment portion 47 forms an abutment surface 48. The abutment surface 48 is capable of abutting against the upper surface 33 of the protruding side of the convex portion 4 of the object to be fixed 3. As a result, when the punch 10 descends and approaches the workpiece during operation of the crimping device, the difference (displacement) between the position level of the punch tip and the position level of the upper surface of the object to be fixed regulates the distance between the punch tip position and the upper surface position of the object to be fixed.

The cutout 43 forms a thin-walled portion 49. When the molded product that holds the workpiece has a complex shape, the thin-walled portion 49 can enter the space by utilizing the gap or small space in the complex-shaped part.

The notch 43 in the workpiece top surface stopper 40 forms a space that allows the tip 12 of the punch 10 to be inserted and a space that avoids interference with the object to be fixed 3.

This allows the tip 12 of the punch 10 to approach the object 3 without interfering with the specific diameter portion 7, such as a protrusion, of the object 3 on the work side. This expands the allowable range of work shapes that can be fixed by thermal crimping.

A PLC (programmable logic controller) as a control device (not shown) controls the power supply to the punch 10 and controls the temperature of the pressing portion 17 of the punch 10. The amount of power supplied to the punch 10 is controlled via a transformer according to a predetermined procedure, and the punch 10 is heated.

Next, the operation will be described.
The workpiece 1 to be joined is made up of a fixing member 2 made of thermoplastic resin and a fixed object 3 made of thermoplastic resin. The fixing member 2 has a convex portion 4 on its outer surface, and the fixed object 3 has a hole 6 into which this convex portion 4 fits. The workpiece 1 is in a state in which the convex portion of the fixing member is inserted into the hole of the fixed object. The workpiece in this state corresponds to a molded product 70 before molding.

FIG. 6A shows a state in which the tip of the punch 10 of the thermal crimping device 20 abuts against the top surface 5 of the protrusion 3 of the fixing member 2.
Fig. 6(B) shows a state in which the protruding portion of the convex portion 4 pressed by the pressing portion 11 at the tip of the punch 10 from the state shown in Fig. 6(A) is thermally melted and deformed to become a boss portion 8. In this state, the fixing member 2 and the object to be fixed 3 are joined by crimping. The workpiece in this state corresponds to the molded product after molding.
(About operation)

Next, the operation of the thermal crimping device of this embodiment will be described with reference to Figures 6, 7, 8, and 9.

The workpiece is brought below the thermal crimping device 20 with the protrusion 4 of the object to be fixed 3 inserted into the hole 6 of the fixing member 2.

The pre-molded product 70, which corresponds to a workpiece having multiple protrusions 4, is placed on a pallet 80 as shown in FIG. 7(A) and is transported below the thermal crimping device 20.

As shown in FIG. 7(A), before the crimping operation begins, the tip 12 of the punch 10 of the thermal crimping device 20 is in an initial position in the sky. Before the crimping operation begins, a pallet 80 carrying the molded product 70 before molding is brought in below the punch 10.

Next, the frame 23 is lowered by the driving of the driving unit 22, and the punch 10 shown in FIG. 7(A) is lowered to the position shown in FIG. 7(B).
Electricity is applied to the punch 10 of the thermal crimping device 20, and the heated punch 10 is lowered in the direction of the arrow by the distance a shown in Figure 7, and as shown in Figure 6 (A), the pressure surface 15 of the pressing portion 17 of the tip 12 of the punch 10 comes into contact with the top surface 5 of the convex portion 4 of the object to be fixed 5, and pressing begins.

Immediately after pressing begins, the compression coil spring 31 shown in FIG. 1, which corresponds to the biasing means, contracts and bends, after which the tip 12 of the punch 10 further descends and is thermally melted and deformed from the top surface 5 of the convex portion, forming the welded boss portion 8 shown in FIG. 6 (B).

At this time, the abutment surface 48 of the workpiece upper surface stopper 40 mechanically coupled to the holder body 261 of the punch holder 26 abuts against the workpiece upper surface 33 of the object 3 to be fixed of the workpiece 1. As a result, when the tip 12 of the punch 10 approaches the workpiece during operation of the thermal crimping device 20, the abutment surface 48 (lower surface) of the workpiece upper surface stopper 40 mechanically coupled to the punch holder abuts against the upper surface 33 of the workpiece before the tip of the pressing portion of the tip of the punch comes into contact with the workpiece upper surface 33.
Therefore, the punch 10 can be lowered by the stroke amount required for crimping.

As shown in Figures 7(A), (B), and (C), if the distance between the workpiece upper surface 33 at the crimping portion and the upper end of the frame 23 is L1 before the crimping operation starts, L2 before the pressing starts after the punch descends, and L3 after the pressing ends after the punch descends, the relational equation is as follows.

L2<L3<L1

As shown in FIG. 7(C), the difference (displacement) between the position level of the tip of the punch 10 and the top surface level of the object to be fixed 3 is regulated by regulating the distance between the tip of the punch and the top surface of the object to be fixed.

As a result, when the pre-molded product 70 is brought below the heat crimping device, even if the height of the workpiece top surface relative to the heat crimping device is not uniform, the position of the descending end of the tip 12 of the punch 10 will be constant relative to the workpiece top surface 33. This makes it possible to prevent burrs from occurring during heat crimping fixation, as will be explained in comparison with the comparative embodiment described below.

In this embodiment, when fixing an object to be fixed to a thermoplastic resin molded product (resin substrate), a protruding portion for crimping, called a welding boss, is formed on a part of the thermoplastic resin molded product, and this welding boss is passed through a fixing hole formed on the side of the object to be fixed so that its tip protrudes from the fixing hole, and the pressing portion of the tip of the punch is pressed against the top surface of this protruding protrusion, and the heat from the tip of the punch causes the top surface side of the tip of the protrusion to melt and deform, crushing the protrusion, thereby thermally crimping the object to be fixed to the thermoplastic resin molded product.

Example applications of the present invention include crimping bosses on resin cases, crimping pins on printed circuit boards, crimping resin lens frames, and assembling precision molded products and parts.

(Comparison with comparative form)
The present embodiment will be described in comparison with a comparative embodiment.
The thermal crimping device according to the comparative embodiment shown in FIG. 10 differs from the above embodiment in that it does not have a work surface stopper.

In both the comparative embodiment and this embodiment, the workpiece is placed on a pallet and transported to the thermal crimping device, and then a punch is lowered from above, pressing the heated pressure surface 65 of the punch against the protrusion 4 of the workpiece 1, causing the protrusion 4 to thermally melt and deform, and crimping and fixing the fixing member and the object to be fixed.

However, with the comparative thermal crimping device, as the tip of the punch 60 descends, the annular protrusion 66 at the tip of the punch bites into the top surface of the object to be fixed, resulting in the bite amount δ shown in Figure 10, and causing damage such as burrs on the top surface of the object to be fixed 3 as a molded product.

One of the causes of burrs is that the height position (top surface position of the object to be fixed) of the workpiece 1 brought under the heat crimping device is not uniform between workpieces. The top surface position level of the object to be fixed to the workpiece is not uniform (even) between workpieces.

In this embodiment, the amount of movement of the lower end of the punch tip during operation of the thermal crimping device is restricted to prevent the generation of burrs.

In this embodiment, when the punch moves (descends) toward the workpiece during thermal crimping, the lower surface of the workpiece upper surface stopper abuts against the upper surface of the workpiece before the tip of the pressing part of the punch contacts the upper surface of the workpiece (object to be fixed).

Therefore, when the punch moves up and down, the difference between the level of the lower surface of the workpiece upper surface stopper and the level of the punch tip position is constant, so a constant distance is maintained between the punch tip position and the workpiece upper surface position when the punch descends relative to the workpiece upper surface. This prevents the tip of the punch from biting into the upper surface of the fixed object before it bites into the upper surface of the fixed object, even if the height of the works placed on the pallet is uneven.
Therefore, damage such as burrs on the upper surface of the workpiece can be prevented.
(Embodiments of the present invention)

An embodiment of the crimping device according to the first aspect of the present invention is as follows.
The abutment surface of the workpiece top surface stopper is an abutment surface that maintains the pressing portion at the same level as the top surface (33) of the fixed object or at a level spaced apart from the top surface to an extent that does not cause damage such as burrs to the fixed object when the tip of the pressing portion approaches the surface on the side that forms the convex portion of the fixed object.
This prevents the tip of the punch from digging into the workpiece, suppresses the occurrence of burrs, and improves the quality of the molded product.

The pressing portion has a pressure surface (15) capable of coming into contact with the top surface (5) of the protrusion, and an annular protrusion (16) formed on the outer ring portion of the pressure surface.
This allows the protrusion to be plastically deformed to form a boss, thereby ensuring reliable crimping and fixing of the molded product.

The crimping device may include a biasing means (31) for biasing the punch holder in one direction against the frame.
This makes it possible to absorb the impact force when the punch is pressed, to appropriately form a boss portion due to deformation of the convex portion, and to manufacture a high-quality molded product that is fixed by crimping.

The crimping device may be provided with a linear guide (25) that guides the punch holder so that it can move relative to the frame. This, combined with the deflection caused by the biasing means, absorbs the impact force when the punch is pressed, properly forms a boss portion due to deformation of the convex portion, and produces a high-quality molded product that is crimped and fixed.

The crimping device includes a base (21) and a drive unit (22) that moves the frame up and down relative to the base. The crimping device can be driven by linking the up and down movement of the punch with the up and down movement of the frame.

The workpiece upper surface stopper may have a thin portion (49) that ensures a space near the pressing portion of the punch so as not to interfere with the object to be fixed.
As a result, even if the pre-molded product has a complex shape, if there is a small space around the convex portion and a thin-walled portion can be inserted into that space, the work top surface stopper will perform the stopper function during the crimping operation, resulting in a highly convenient crimping device that can handle pre-molded products with complex shapes.

The workpiece upper surface stopper may have a notch (43) that allows for the presence of a protrusion (7) protruding from the upper surface of the object to be fixed so as not to interfere with the object to be fixed.
Similarly, even if the pre-molded product has a complex shape, if there is a small space around the convex portion and a thin-walled portion can be inserted into that space, the work top surface stopper will perform the stopper function during the crimping operation, resulting in a highly convenient crimping device that can handle pre-molded products with complex shapes.

The crimping device can be applied to a crimping device that can pass electricity through the punch to heat the tip of the punch and can thermally melt and deform the convex portion when the pressing portion presses the convex portion.

In the case of a heat crimping device, the inner wall of the annular protrusion can be provided with an annular tapered inner wall surface (14) that facilitates removal after heat crimping, thereby improving the quality of the molded product after molding.
Other Embodiments

The present invention has been described as a method for manufacturing a molded product by thermal crimping, but it can also be applied to a crimping device that crimps and fixes an object to a fixing member by applying pressure to the pressing part without heating the punch by passing an electric current through it.

The present invention can be applied to a crimping device that uses a cold punch that does not apply heat.
In the above embodiment, the thermal crimping device using the electrically heated punch has been described. However, in the present invention, the thermal crimping device may be of a heating type other than the electrically heated type.

Although a resin material is used for the object to be fixed in the above embodiment of the present invention, it may be a metal material, an inorganic material, or other material.
The workpiece upper surface stopper shown in the above embodiment is merely one embodiment, and it goes without saying that the shape of the workpiece upper surface stopper of the present invention is not limited to this.

The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention.

1 Work,
2 fixing member,
3. Fixed object,
4 convex portion,
5 Top surface,
6 holes,
10 punches,
12 tip portion,
15 Curved surface (pressure surface)
16 Annular protrusion,
17 pressing portion,
20 heat crimping device,
21 Base,
22 Drive unit,
23 frames,
25 Linear guide,
27 punch holder extension,
31 compression coil spring (biasing means),
33 Work top surface,
40 Work top stopper,
43 notch,
48 abutment surface,
49 Thin-walled portion,
50 inner wall,
70 Molded products,
80 pallets.

Claims (10)

A crimping device for crimping and fixing a fixing member (2) made of resin having a convex portion (4) to a fixed object (3) having a hole (6) into which the convex portion is inserted, comprising:
A frame (23);
a punch holder (26) that is movable up and down relative to the frame;
a punch (10) attached to the punch holder and having a pressing portion (17) at a tip thereof capable of pressing the convex portion of the fixing member;
a workpiece upper surface stopper (40) mechanically coupled to the punch holder;
The workpiece upper surface stopper has an inner wall (50) facing the tip of the punch via a gap, and an abutment surface (48) that can abut against an upper surface (33) of the object to be fixed on the protruding side of the convex portion when the convex portion of the fixing member is inserted into the hole of the object to be fixed, and prevents damage to the object to be fixed from occurring when the pressing portion approaches the upper surface ,
A crimping device in which the abutment surface of the workpiece top surface stopper maintains a level equal to or spaced apart from the top surface of the fixed object to an extent that does not cause damage such as burrs to the fixed object when the tip of the pressing portion approaches the top surface of the fixed object . The crimping device according to claim 1, further comprising an extension (27) of the punch holder, the extension being mechanically connected to the workpiece upper surface stopper. The crimping device according to claim 1, wherein the pressing portion has a pressure surface (15) that can come into contact with the top surface (5) of the convex portion, and an annular convex portion (16) formed on the outer ring portion of the pressure surface. The crimping device according to claim 1, further comprising a biasing means (31) for biasing the punch holder in one direction against the frame. The crimping device according to claim 1, further comprising a linear guide (25) that guides the punch holder so that it can move relative to the frame. The crimping device according to claim 1, comprising a base (21) and a drive unit (22) that moves the frame up and down relative to the base. The crimping device according to claim 1, wherein the workpiece upper surface stopper has a thin-walled portion (49) that ensures space near the pressing portion of the punch so as not to interfere with the object to be fixed. 2. The crimping device according to claim 1, wherein the workpiece upper surface stopper has a notch (43) that allows the presence of a protrusion (7) protruding from the upper surface of the object to be fixed so as not to interfere with the object. 2. The crimping device according to claim 1, wherein an electric current can be passed through the punch to heat the tip of the punch, and when the pressing portion presses against the convex portion, the convex portion is thermally melted and deformed, thereby thermally crimping the fixing member and the object to be fixed . The pressing portion has a pressing surface (15) capable of contacting the top surface (5) of the protruding portion, and an annular protruding portion (16) formed on an outer ring portion of the pressing surface,
10. The crimping device according to claim 9 , wherein the inner wall of the annular projection has an annular tapered inner wall surface (14) for facilitating removal after heat crimping.

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