JP2008036711A - Screw fixing device and method of manufacturing screw fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the structure of a screw fixing tool and a method of manufacturing the screw fixing tool by which a screw cutting is prevented from being forgotten and a product on which screw cutting is surely performed by performing the whole of a series of manufacturing process including the formation of a thread groove by press processing. <P>SOLUTION: This screw fixing tool 1 is provided with: a flange part 13 which is fixable to the main body frame 50 by caulking to a hole 51 which is formed on the main body frame 50; and a cylindrical part 10 which is continued to the flange part and in which a space part 15 is made to be present in the inner part. The whole of the series of manufacturing process including the formation of a thread groove may be performed by forming one turn of the thread groove 20 by press processing on the top face 11 by which the opposite part of the flange of the cylindrical part is closed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a screw fixing tool for fixing a screw to a main body frame side when a circuit board is mounted on a main body frame of a liquid crystal television, for example, and a manufacturing method thereof.

Conventionally, for example, a circuit board is mounted on a main body frame of a liquid crystal television using a fixing tool and a screw.
As shown in FIG. 4, the fixing tool 40 has a screw groove 42 spirally cut from the upper surface at the center of the cylindrical portion 41, and a flange portion 43 having a larger diameter than the cylindrical portion 41 at the lower end.

Then, as shown in FIG. 5, the fixing device 40 is fixed and integrated with the main body frame 50 by caulking 45 the flange portions 43 of the fixing device 40 to the plurality of holes 51 formed in the main body frame 50. Then, the circuit board 60 is disposed on the upper surface side of the fixture 40 and the screw 70 is inserted into the hole 61 of the circuit board 60 and the screw groove 42 of the fixture 40, so that the circuit board 60 is attached to the main body frame 50. And was fixed.
Further, during the caulking process 45, the bulging portion on the main body frame 50 side enters the cutting groove portion 44 formed in the cylindrical portion 41 so that the fixing is ensured.

The fixture 40 described above has a problem in that it takes time and labor to manufacture because each cylindrical portion 41 needs to be threaded by a manual operation or a secondary processing. Further, since it is necessary to thread the thread grooves 42 one by one with respect to a large number of fixtures 40, the thread grooves 42 are notched due to a mistake in processing (forgetting to cut the screw) of several manufactured fasteners. There was a case where it was not done.
Then, when the fixing tool 40 is caulked 45 to the main body frame 50, if the screw groove 42 is not cut into one of the fixing tools 40, the circuit board 60 cannot be mounted, There is a disadvantage that the integrated main body frame 50 is treated as a defective product.

Various fixing devices for fixing the screw have been proposed as shown in the following patent document, but there is no structure suitable for fixing the circuit board 60 to the main body frame 50.
JP-A-10-285720 JP 09-137816

  The present invention has been proposed in view of the above circumstances, and by performing a series of manufacturing processes including the formation of thread grooves in a screw fixture by a press process, forgetting of thread cutting is prevented and threading is reliably performed. It is an object of the present invention to provide a structure of a screw fixture from which a product can be obtained and a method for manufacturing the screw fixture.

In order to achieve the above object, the invention of claim 1 includes a flange portion 13 that can be fixed to the flat plate (main body frame 50) by being caulked 45 in a hole 51 formed in the flat plate (main body frame 50). The screw fixture 1 includes a cylindrical portion 10 that is continuous to the flange portion 13 and has a space portion 15 in the inside thereof, and includes the following configuration.
On the top surface 11 that closes the opposite flange portion of the cylindrical portion 10, a screw groove 20 (one round) is formed by pressing.

According to the second aspect of the present invention, a plurality of screw fixtures 1 are respectively fixed to a flat body frame 50 contained in an electrical appliance or the like by a caulking process 45, and a screw 70 is attached to each of the screw fixtures 1. A cylindrical screw fixing tool 1 for fixing the circuit board 60 via the above structure includes the following configuration.
A flange portion 13 that can be fixed to the main body frame 50 by being caulked 45 in a hole formed in the main body frame 50 is provided.
A cylindrical portion 10 is provided which is continuous with the flange portion 13 and has a space portion 15 inside.
The top surface 11 that closes the opposite flange portion of the cylindrical portion 10 is provided with a screw slot 20 (one round) formed by pressing.

The invention of claim 3 is a method of manufacturing the cylindrical screw fixture 1 having the flange portion 13 at one end and the thread groove 20 at the other end by pressing the strip plate 30 multiple times in a flow operation. The following steps are included.
Body forming process. In this step, the cylindrical body is formed by a plurality of press processes so that one end is open and the other end has a top surface 11.
Hole formation process. In this step, a hole 34 similar to a gourd shape in which a circular portion 34a and a long hole portion 34b are connected to the top surface 11 of the cylindrical body is punched by pressing.
Thread groove machining process. In this process, one screw (one round) of the screw groove 20 provided with the step absorption hole 21 is formed by press working on the top surface 11 in which the hole 34 similar to the gourd type is formed.
Cutting process. In this step, a cylindrical body in which a thread groove is formed from the belt-like plate is cut off so as to have a flange portion 13 around it to obtain a screw fixture.
According to a fourth aspect of the present invention, in the hole forming step of the screw fixing device manufacturing method according to the third aspect, the basic shape of the hole drilled in the top surface of the cylindrical body is a circular portion connected to a long hole portion. In the vicinity of the connection between the circular portion and the long hole portion, the shape is asymmetrical.

According to the screw fixture 1 of the present invention, the screw groove 20 into which the screw 70 is screwed is formed by the screw groove 20 of one mouth (one round) by the press working process, so that a series of manufacturing steps are all performed by the press process. Thus, the structure of the screw fixture 1 in which the screw groove 20 is reliably formed can be obtained.
In addition, when manufacturing a screw fixture, the hole to be drilled in the top surface of the cylindrical body by pressing (a shape in which a long hole portion is connected to a circular portion) is made asymmetrical, so that the subsequent screw groove About the thread groove 20 formed in a manufacturing process, it can be set as the thread groove which increased the part which has contacted the screw thread, and can ensure the stability at the time of screw mounting | wearing.

An example of an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the screw fixture 1 according to the present invention is configured to have a cylindrical portion 10 that is open on one side and closed on the other side by a top surface 11. A flange portion 13 that protrudes to the outer periphery of the cylindrical portion 10 is formed at the opening-side lower end of the cylindrical portion 10. On the peripheral surface of the flange portion 13, irregularities including a mountain shape 13 a and a valley shape 13 b are continuously formed. This is to facilitate deformation of the inner wall portion of the hole due to the unevenness when the flange portion 13 is caulked to the hole of the flat plate, and to prevent rotation during rotation (prevention of rotation). It is.
The diameter of the flange portion 13 is slightly larger than the diameter of the hole in the main body frame to which the screw fixture 1 is mounted in order to perform the caulking process. The state in which the screw fixture 1 is attached to the main body frame by the caulking process will be described later.

The top surface 11 of the cylindrical portion 10 is formed with a hole to be a single mouth (one turn) of the screw groove 20 by press working. As shown in FIGS. 1 (a) and 1 (c), the thread groove 20 is formed on a perforated hole (a hole 34 having a shape similar to a gourd shape shown in FIGS. 2 and 6 described later). It is formed by deforming by press working into a shape that fits corresponding to one screw thread (one turn) of a screw attached to the part. By providing a step absorption hole 21 in the screw groove 20 (hole), a step corresponding to the screw thread can be formed in the screw groove 20 due to the presence of this portion.
That is, the screw groove 20 is configured to have a step corresponding to one screw thread across the step absorption hole 21 and a spiral shape corresponding to one screw thread.

  In addition, a space portion 15 in which the tip portion of the screw can be stored is formed inside the cylindrical portion 10. The length of the cylindrical portion 10 is set according to the length of the screw fixed to the screw fixture 1 and the height required for design.

Next, a basic manufacturing method of the screw fixture 1 having the above structure will be described with reference to FIG.
The screw fixture 1 includes a cylindrical body having a flange portion 13 at one end and a thread groove 20 at the other end by pressing the belt-like plate 30 a plurality of times in the vertical direction by an upper die and a lower die in a flow operation. It is formed by doing.
The series of steps shown in FIG. 2 is performed in close proximity to the belt-like plate 30 by synchronizing the upper and lower mold plates (not shown) arranged above and below the belt-like plate 30 made of metal pieces.・ Each step is performed at the same time in a state where the strip plate 30 is clamped by each plate, and each plate is separated after the step is completed, and the strip plate 30 is moved rightward in the drawing by a predetermined distance. Each processing portion is sequentially moved to the next step.

  First, cylindrical bodies 31, 32, and 33 having one end opened and a top surface at the other end by a plurality of press workings (sequential die processing) in FIGS. Are sequentially molded, and finally, press processing is performed so as to have the cylindrical portion 10 on which the top surface 11 is formed (main body forming step). In this process, a desired cylindrical body cannot be obtained by a single press process. Therefore, a cylindrical body having a cylindrical portion 10 having a desired shape is formed by sequentially performing a plurality of press processes in a flow manner. Is possible (FIG. 2D).

Next, the elongated hole portion 34b is connected to the substantially circular portion 34a as shown in FIG. 6 by press working that punches the top surface 11 of the molded cylindrical body with a punch (not shown). A hole 34 having such a shape (a shape similar to a gourd shape) is drilled (hole forming step) (FIG. 2 (e)).
As shown in FIG. 6, the hole 34 is formed in a shape in which the long hole portion 34 b is connected to the substantially circular portion 34 a. The hole 34 is not symmetrical on the left and right in FIG. 6, but is formed such that the radius R1 of the hole in the left portion of the drawing at the connecting portion between the substantially circular portion 34a and the elongated hole portion 34b is larger than the radius R2 on the right side. Thus, the shape is asymmetrical in the vicinity of the connection between the substantially circular portion and the long hole portion. This is to ensure the stability of screw mounting by increasing the number of screw groove portions that are in contact with (supported) when the screw is mounted in a thread groove formed by press working, which will be described later. is there.

Subsequently, the top surface 11 including the hole 34 is pressed to deform the hole 34, and as shown in FIG. 7, the thread groove 20 and the long hole portion 34 b obtained by deforming the substantially circular portion 34 a. By forming the step absorption hole 21 that is deformed, one mouth (one round) of the screw groove 20 is formed (screw groove processing step) (FIG. 2 (f)).
That is, in the thread groove processing step, the elongated hole portion 34b is deformed, so that it is between the high position and the low position of the thread groove 20 as shown in FIGS. 7 (a), (b), and (c). A step absorption hole 21 for interposing a space without a thread groove is formed, and the substantially circular portion 34a is deformed to form a spiral thread groove 20 having a height difference of one round.
Further, in the screw groove 20, when the screw groove 20 having the step absorption hole 21 is formed by pressing so that the left side in FIG. 7 is the start of the screw pitch and the right side is the end of the screw pitch, It is necessary to increase the thread groove portion in contact with (support) and to bend the end side of the right screw pitch high (see FIG. 7C). Therefore, in order to make the end position of the right screw pitch longer than that on the left side with respect to the bending position, the hole 34 is asymmetric in the state of FIG. 6 before press working.

  Next, a cut groove in which unevenness that becomes the outer periphery of the flange portion 13 is repeated is formed by press working around the cylindrical body (FIG. 2G).

Finally, by punching out with a punch (not shown), the cylindrical body in which the screw groove 20 is formed is cut off from the belt-like plate 30 to obtain the screw fixture 1 as a product (FIG. 2). (H)).
In the series of manufacturing processes described above, the series of manufacturing processes including the formation of the thread grooves 20 are all performed by press processing (sequential die processing), so that forgetting the threading is prevented and the threading process is reliably performed ( The screw fixture 1) in which the thread groove 20 is formed can be obtained only by pressing.

Next, how to use the above-described screw fixture 1 will be described with reference to FIG.
The screw fixture 1 is for mounting the circuit board 60 on a main body frame 50 such as a liquid crystal television, and is used at a plurality of locations corresponding to the four corners of the circuit board 60, for example.

First, the screw fixture 1 is inserted into the plurality of holes 51 formed in the main body frame 50 from the top surface 11 side (FIG. 3A). Since the diameter of the flange portion 13 of the screw fixture 1 is formed larger than the hole 51, the flange portion 13 abuts against the back surface of the main body frame 50.
In this state, by pressing the screw fixture 1 arranged on the contact plate 100 from the main body frame 50 side, the flange portion 13 is pushed into the hole 51, and the mountain shape 13a and the valley shape 13b around the flange portion 13 are the main body. It is buried on the frame 50 side (FIG. 3B).

The circuit board 60 is placed on the fixed screw fixture 1, the hole 61 provided in the circuit board 60 is aligned with the top surface 11 portion of the screw fixture 1, and the screw 70 is attached. Since the hole 61 formed in the circuit board 60 is formed larger than the screw diameter of the screw 70, the screw thread of the screw 70 is fitted only in the screw groove 20 of the screw fixture 1, and the screw 70 is screwed. By doing so, the fitting portion (one valley portion) moves to the screw base side, and the screw 70 is fastened between the screw fixture 1 and the circuit board 60 (FIG. 3C).
As shown in FIG. 3 (c), one screw thread valley portion 71 is located in the screw groove 20, and the screw thread top line below the valley portion 71 is in the screw groove 20. The screw 70 is fixed with respect to the screw fixture 1 by abutting along.

  According to the structure of the screw fixture 1 described above, the screw groove 20 to which the screw 70 is screwed is formed by the screw groove 20 of one mouth (for one round) by a series of press processing, so that the screw groove 20 is reliably formed. The screw fixing tool 1 can be obtained, and as described in the prior art, no defective product is generated at the stage where the screw fixing tool 1 is mounted on the main body frame 50, and the generation of useless members is prevented. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS One Example of the screw fixing tool of this invention is shown, (a) is plane explanatory drawing, (b) is side surface explanatory drawing, (c) is AA sectional view explanatory drawing of the top view. (A)-(h) is process explanatory drawing for demonstrating the manufacturing process of the screw fixing tool of this invention. (A)-(c) is sectional explanatory drawing for demonstrating how to use the screw fixing tool of this invention. The structure of the conventional screw fixing tool is shown, (a) is plane explanatory drawing, (b) is side surface explanatory drawing, (c) is sectional explanatory drawing. It is sectional explanatory drawing which shows the fixed state of the main body frame and circuit board which use the conventional screw fixing tool. It is a top view which shows the shape of the hole drilled by the hole formation process in the manufacturing process of a screw fixing tool. (A), (b), and (c) show the thread groove pressed in the thread groove machining process in the manufacturing process of the screw fixture, (b) is a plane explanatory view, and (a) is an A in (b). Arrow explanatory drawing, (c) is BB sectional explanatory drawing of (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw fixing tool 10 Cylindrical part 11 Top surface 13 Flange part 15 Space part 20 Screw groove 21 Level | step difference absorption hole 30 Strip | belt-shaped board 34 Hole 43 Flange part 45 Caulking process 50 Main body frame 60 Circuit board 70 Screw 71 Valley part

Claims (4)

A screw fixture comprising: a flange portion that can be fixed to the flat plate by caulking in a hole formed in the flat plate; and a cylindrical portion that is continuous with the flange portion and has a space inside. ,
A screw fixture, wherein a single screw groove is formed by press working on a top surface that closes an opposite flange portion of the cylindrical portion. Cylindrical shape when fixing a plurality of screw fixtures to a flat body frame contained in electrical appliances by caulking, and fixing a circuit board to each screw fixture via screws Screw fixing tool,
A flange portion that can be fixed to the main body frame by being caulked in a hole formed in the main body frame;
A cylindrical portion that is continuous with the flange portion and has a space inside;
A screw fixture, comprising: a top surface that closes an anti-flange portion of the cylindrical portion, and a single screw groove formed by pressing. A method of manufacturing a cylindrical screw fixture having a flange portion at one end and a thread groove at the other end by pressing the strip plate multiple times in a flow operation,
A main body forming step of forming a cylindrical body by a plurality of press processes so that one end is open and a cylindrical shape having a top surface at the other end; and
A hole forming step of drilling a hole in the top surface of the cylindrical body by pressing; and
A thread groove processing step of forming a single thread groove on the top surface where the hole is formed by press processing;
A cutting process step of cutting a cylindrical body in which a thread groove is formed from the belt-like plate so as to have a flange portion around it,
The manufacturing method of the screw fixing tool characterized by the above-mentioned. In the hole forming step, the hole drilled in the top surface of the cylindrical body has a basic shape in which a long hole is connected to a circular part, and is asymmetrical in the vicinity of the connection between the circular part and the long hole. The manufacturing method of the screw fixture of Claim 3 which is the shape of these.

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