JP5019593B2 - Manufacturing method of screw fixture - Google Patents

Description

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

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. 10, the fixing tool 40 has a screw groove 42 spirally cut from the upper surface at the center of the column portion 41, and a flange portion 43 having a larger diameter than the column portion 41 at the lower end.

  Then, as shown in FIG. 11, 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.

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, a situation occurs in which the thread grooves 42 are not cut due to a processing error (forgetting to cut the threads) for several fixtures. was there.
When the fixing tool 40 is caulked 45 to the main body frame 50 and the screw groove 42 is not cut into one of the fixing tools 40, the circuit board 60 cannot be mounted and integrated. There is a problem in that the 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

Accordingly, the present inventor has applied for a screw fixing device having a structure in which a thread groove is formed in the screw fixing device by press processing to prevent forgetting of screw cutting and a product that is reliably threaded can be obtained. The proposal was made at -188840.
However, in the structure of the screw fixture shown in Japanese Patent Application No. 2006-188840, when the flange portion of the screw fixture is caulked and the screw fixture is fixed and integrated with the main body frame, the caulking strength is high. There was a case where it was insufficient.

  In addition, the conventional screw fixture shown in FIG. 10 is provided with an annular groove portion 44 in which the periphery of the cylindrical portion 41 becomes a groove at the flange 43 side end of the cylindrical portion 41 in order to ensure the strength during the caulking process. However, since the fixing tool 40 is formed by a lathe one by one, the processing is complicated.

  The present invention has been proposed in view of the above circumstances, and forgets to cut the thread by performing a series of manufacturing processes including the formation of the thread groove and the formation of the groove portion for the caulking process in the screw fixture by the press process. It is an object of the present invention to provide a method for manufacturing a screw fixture that can prevent and securely obtain a threaded product and can secure sufficient caulking strength.

In order to achieve the above object, the method of the present invention is a cylindrical screw having a flange portion at one end and a thread groove at the other end by press-working the strip plate in the vertical direction by the upper die and the lower die in a flow operation. A method of manufacturing a fixture, comprising the following steps.
Body forming process. In this step, a cylindrical body is formed by a plurality of press processes using the upper mold and the lower mold so that one end is open and a top surface is formed on the other end.
Hole formation process. In this step, a hole is drilled in the top surface of the cylindrical body by pressing.
Thread groove machining process. In this step, one round (one round) screw groove having a step absorption hole is formed on the top surface where the hole is formed by press working.
Groove processing step. This process incorporates a cam mechanism that moves the vertical movement of a corresponding upper mold plate into a horizontal movement and moves it against a predetermined lower mold plate to face the cylindrical body. By performing press working from the horizontal direction, a groove is formed on the base side surface of the cylindrical body by press working.
Cutting process. In this step, a cylindrical body in which a thread groove is formed is cut off from the belt-like plate so as to have a flange portion around it.

  The method of claim 2 is characterized in that, in the groove processing step of the method of manufacturing the screw fixture of claim 1, two pairs of the cam mechanisms are arranged, and four grooves are simultaneously formed in the cylindrical body.

According to the method of the present invention, the screw groove 20 into which the screw 70 is screwed is formed by one round (one round) of the screw groove 20 provided with the step absorption hole 21 by press working, and the end of the cylindrical portion 10 on the flange portion side. The plurality of groove portions 14 are formed by press processing, so that a series of manufacturing processes can be performed by press processing, and the screw groove 20 is reliably formed and sufficient caulking strength is ensured by the presence of the groove portions 14. It can be set as the structure of the screw fixing tool 1 which can be performed.

BEST MODE FOR CARRYING OUT THE INVENTION

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 manufactured by the method of the present invention includes 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.

On the top surface 11 of the cylindrical portion 10, a screw groove 20 is formed once (for one round) by press working. As shown in FIGS. 1 (a) and 1 (c), the thread groove 20 is a screw thread that is attached to this portion with respect to a perforated hole (a hole 34 similar to a gourd shape of FIG. 2 described later). It is formed by deforming by press working into a shape that fits into one mountain. By providing a step absorption hole 21 in the hole (screw groove 20), a step can be formed in the screw groove 20 due to the presence of this portion.
That is, the screw groove 20 has a step corresponding to one mountain with the step absorption hole 21 interposed therebetween, and has a spiral shape corresponding to one screw thread.

Four groove portions 14 are formed at the flange portion 13 side end of the cylindrical portion 10 by press working. Each groove part 14 is formed in the cylindrical part 10 in the position which mutually opposes at equal intervals, and each comprises the arch-shaped recessed part. This groove portion 14 is used to make it difficult for the screw fixture 1 to come off from the member to be fixed in the caulking process described later.
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 FIGS.
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. (FIG. 2D).

Next, a hole 34 that resembles a gourd mold is punched in the top surface 11 of the molded cylinder by punching with a punch (not shown) (hole forming step) (FIG. 2 (e)). .
Subsequently, by performing press working with respect to the top surface 11 include holes 34 similar to gourd shape, one by deforming the hole 34 similar to gourd shape, forming a screw groove 20 and the step absorption holes 21 A circumferential (one round) thread groove is formed (thread groove machining step) (FIG. 2F).

  Next, two pairs (four pieces) of groove portions 14 are formed on the base portion of the cylindrical body (on the belt-like plate 30 side) so as to face each other by pressing (FIG. 2G). The processing of the groove portion 14 is not performed by pressing in the normal vertical direction (upper die / lower die), but is performed by incorporating a cam mechanism in the lower die in the horizontal direction and pressing from the horizontal direction (groove portion processing step). .

  That is, as shown in FIG. 3, when the strip 30 moves in the direction of the arrow, the four pressing plates 103 are cylindrical with respect to the predetermined plate 111 of the lower mold 110 that performs the processing of FIG. Two pairs of cam mechanisms 100 operating from the horizontal direction with respect to the body 10 are disposed. The direction of horizontal movement by the two pairs of cam mechanisms 100 is inclined by 45 degrees with respect to the moving direction of the strip 30, and the horizontal movements are arranged so as to intersect at right angles.

As shown in FIGS. 3 to 5, each cam mechanism 100 is fixed to the cam mechanism main body 101 coupled to the lower mold 110, the slide body 102 moving in the cam mechanism main body 101, and the slide body 102. The pressing plate 103 and the interlocking plate 125 connected to the upper mold 120 and operating in the vertical direction are provided.
A plate 121 is movably connected to the upper mold 120 through a buffering means 123 such as a spring together with a guide member 124, and is formed on a cylindrical portion 122 formed on the lower surface of the plate 121 and on the upper surface of the plate 111 of the lower mold 110. The cylindrical body 10 formed in the belt-like body 30 is sandwiched between the inner side surface and the outer side surface by the formed cylindrical groove portion 112.

One end side of the stop shaft 104 is fixed to the end surface of the slide plate 102 so that the other end passes through the side portion of the cam mechanism body and faces the outside. By attaching the pulling spring 106 between the two, the slide plate 102 is always urged outward (the state shown in FIG. 5A).
At the front end of the pressing plate 103, a rectangular protrusion 107 for forming the groove portion 14 with respect to the base portion of the cylindrical body 10 is formed.
The contact surface between the interlocking member 125 and the slide plate 102 is provided with an inclined surface 125a and an inclined surface 102a, respectively, and vertical movement by the interlocking member 125 can be converted into horizontal movement by sliding the inclined surfaces ( The state is as shown in FIG.
In addition, the interlocking body 125 descends in conjunction with the plate 121 when the upper mold 120 descends in the vertical direction. However, after the column portion 122 of the plate 121 is inserted into the cylindrical body 10 of the strip-shaped body 30, The positions of the interlocking member 125 and the plate 121, the buffering means 123, and the like are adjusted so that the lower end inclined surface 125a operates so as to contact the inclined surface 102a of the slide body 102.

Therefore, as shown in FIG. 6, after the cylindrical portion 122 of the plate 121 is inserted into the cylindrical body 10 of the belt-like body 30, the slide body 103 moves against the pulling spring 106, and the rectangular protrusion 107 at the tip thereof. Abuts against the base of the cylindrical body 10 and presses while supporting the position of the inner surface by the cylindrical portion 122 (FIG. 6B), so that the cylindrical portion 10 is not deformed by the pressing force, and the groove portion 14 is highly accurate. Can be formed.
The production of the groove 14 in the cylindrical body 10 by the cam mechanism 100 having the above-described structure is performed in four directions with respect to the cylindrical body 10, so that the base portion of the cylindrical body 10 can be obtained by a single press working with the upper mold 120 and the lower mold 110. Four grooves 14 can be formed on the side surface.

  Then, a cut groove in which irregularities serving as the outer periphery of the flange portion 13 are repeated is formed by press working around the cylindrical body (FIG. 2 (h)).

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). (I)).
Since the series of manufacturing processes described above are all performed by press processing (sequential die processing) including the formation of the thread grooves 20 and the groove portions 14, the forgetting of threading is prevented and the threading process is reliably performed. In addition, a product (a screw fixture 1 in which the screw groove 20 and the groove portion 14 are formed only by pressing) that can secure sufficient caulking strength due to the presence of the groove portion 14 can be obtained.
In addition, according to the manufacturing method described above, since the groove portion 14 is formed by pressing the cam mechanism 100 from four directions with respect to the cylindrical body 10, the groove portion 14 can be reliably engraved with a relatively small pressing force. Is possible.

In the manufacturing method described above, the cam mechanism 100 is operated on the cylindrical body 10 from four directions to perform press working. However, the groove portion 14 is configured by pressing with the cam mechanism from only two opposite directions. Also good. In this case, by setting the tip shape of the pressing plate 103 to a desired shape, for example, it is possible to form two groove portions 14 in which most of the cylindrical portion 10 is concave as shown in FIG. In the case of this example, the groove part 14 of the cylindrical body 10 forms a concave part in a part other than the two surface parts 10a on the surface of the cylindrical part 10.
In each example, a plurality of groove portions are formed. However, the groove portions may be formed by pressing so as to form a recess over the entire circumference of the cylindrical portion.
The other parts of the screw fixture of FIG. 7 have the same configuration as the screw fixture of FIG.

Next, how to use the above-described screw fixture 1 will be described with reference to FIGS. 8 and 9.
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 each of the plurality of holes 51 formed in the main body frame 50 from the top surface 11 side (FIG. 8A). 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 periphery of the flange portion 13 is buried in the main body frame 50 side ( FIG. 8B and FIG. 9A). At this time, the screw fixing tool is attached to the main body frame 50 such that the thickness of the plate of the main body frame 50 bulges 55 into the groove portion 14 and the lower surface of the flange portion 13 is flush with the back surface of the main body frame 50. 1 is fixed by the caulking process 45 (FIGS. 8C and 9B).

The circuit board 60 is installed on the fixed screw fixture 1, the hole 61 provided in the circuit board 60 and the top surface 11 portion of the screw fixture 1 are aligned, and the screw 70 is mounted with a washer 80 interposed. 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. 8D).
As shown in FIG. 8 (d), the screw fitting position is such that one trough portion 71 of the screw thread is located in the screw groove 20, and the screw thread top line below the trough 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 turn ( 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 sufficient caulking strength can be ensured by the presence of the groove portion 14, so that, as described in the conventional example, a defective product is obtained when the screw fixing tool 1 is attached to the main body frame 50. It is possible to prevent the generation of useless members.

BRIEF DESCRIPTION OF THE DRAWINGS It shows an example of embodiment of the screw fixing tool of this invention, (a) is plane explanatory drawing, (b) is side surface explanatory drawing, (c) is AA sectional view explanatory drawing of the top view. (A)-(i) is process explanatory drawing for demonstrating the manufacturing process of the screw fixing tool of this invention. It is plane explanatory drawing which shows the positional relationship of the cam mechanism with respect to the strip | belt shaped object in the manufacturing process of the screw fixing tool of this invention. (A) (b) is a plane explanatory view showing an operation state of a cam mechanism, (a) shows a state before horizontal operation, and (b) shows a state after horizontal operation. (A) (b) is side explanatory drawing which shows the operation state of a cam mechanism, (a) shows the state before horizontal operation, (b) shows the state after horizontal operation. (A) and (b) are expanded sectional explanatory drawings explaining the engraved state of the strip | belt-shaped body by a cam mechanism, (a) shows the state before horizontal operation, (b) shows the state after horizontal operation. The other example of embodiment of the screw fixing tool of this invention is shown, (a) is plane explanatory drawing, (b) is side explanatory drawing, (c) is AA sectional view explanatory drawing of the top view. is there. (A)-(d) is sectional explanatory drawing for demonstrating how to use the screw fixing tool of this invention. (A) And (b) is a partially expanded sectional explanatory view for demonstrating the usage of 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw fixing tool 10 Cylindrical part 11 Top surface 13 Flange part 14 Groove part 15 Space part 20 Screw groove 21 Level | step difference absorption hole 30 Strip plate 34 Hole 45 Caulking process 50 Main body frame 60 Circuit board 70 Screw 71 Valley part 100 Cam mechanism 101 Cam mechanism Main body 102 Slide body 103 Press plate 107 Square protrusion 110 Lower mold 111 Plate 112 Column groove 120 Upper mold 121 Plate 122 Column 123 Buffering means 125 Interlocking body

Claims (2)

A method of manufacturing a cylindrical screw fixture having a flange portion at one end and a thread groove at the other end by performing a plurality of vertical press operations by an upper die and a lower die in a flow operation on a strip plate,
A main body forming step of forming a cylindrical body by a plurality of press operations by the upper mold and the lower mold so that one end is open and the other end has a top surface;
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 (for one round) with a step absorption hole on the top surface where the hole is formed by press working; and
Incorporating a cam mechanism that opposes the predetermined lower plate by converting the vertical movement of the corresponding upper plate into a horizontal movement from the horizontal direction facing the cylindrical body. A groove processing step of forming a groove by press processing on the base side surface of the cylindrical body by pressing;
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.   The screw fixing device manufacturing method according to claim 1, wherein in the groove portion machining step, two pairs of the cam mechanisms are arranged to simultaneously form four groove portions in the cylindrical body.

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