TWI620604B - Metal plate with screw hole, housing, and manufacturing method of metal plate with screw hole - Google Patents

Abstract

The screw hole of the metal plate with the screw hole of the present invention has a cylindrical outer wall portion rising from one side of the metal plate and a cylindrical inner wall folded from the end edge of the outer wall portion to the inner side of the outer wall portion And a female thread is formed on the inner circumferential surface of the inner wall portion.

Description

Metal plate with a screw hole, a frame body, and a metal plate with a screw hole Field of invention

The present invention relates to a metal plate with a screw hole, a frame, and a method of manufacturing a metal plate with a screw hole. More specifically, it is a metal plate with a screw hole which is also provided with a screw hole which is excellent in the reinforcing force of the male screw when it is thinned, and which is also prevented from being damaged by the screw hole. The frame of the metal plate of the screw hole and the manufacturing method of the metal plate with the screw hole mentioned above.

The present application claims priority based on Japanese Patent Application No. 2013-154105, filed on Jan.

Background of the invention

Most of the frames of the outdoor unit or the substation of the air conditioner are formed into metal plates of various shapes by cutting or bending. Since the metal plate and the mounting portion of the other metal plate or the accessory member constituting the frame body are largely screw-shaped, there is a case where the metal plate is formed with a screw hole.

Figure 11 is a view schematically showing a screw hole of a conventional metal plate, It is a longitudinal cross-sectional view when viewed in a section including the central axis of the screw hole. The figure shows a metal plate 510 having a screw hole. To understand the structure, the male screw 550 and the other metal plate 551 having the through hole 551a are further shown by imaginary lines. The metal plate 510 shown in the figure has a cylindrical vertical wall portion 511 that functions as a screw hole (hereinafter, the vertical wall portion 511 is referred to as a screw hole 511). One end of the vertical wall portion 511 is connected to the metal plate body 513, and a female screw 511b is formed on the inner circumferential surface. When the metal plate 510 is attached to the metal plate 551 having the through hole 551a and mounted thereon, the male screw 550 is inserted into the through hole 551a and screwed into the screw hole 511 to be coupled. This screw hole 511 is formed on a metal plate by burring, and is most easily used for processing.

12A and 12B are longitudinal cross-sectional views schematically showing an example of a process for manufacturing a screw hole of a conventional metal plate, and Fig. 12A shows a drilling step, and Fig. 12B shows a step of punching. When the screw hole 511 is machined, first, a pre-drilled hole is drilled in the metal plate 520 to be processed. Pre-drilling can be done by shearing or cutting. When drilling a pre-drilled hole by shearing, a drilling punch 531 and a drilling die 532 as shown in Fig. 12A are used. If the punch 531 and the die 532 are relatively close, a portion of the metal plate 520 is pushed into the through hole of the die 532 together with the punch 531. As a result, a portion of the metal plate 520 is cut by a blade provided in the punch 531 and the die 532, respectively, to separate and drill the pre-drilled hole.

A pre-drilled metal plate 520 is drilled to form an elongated flange as a vertical wall portion. As shown in Fig. 12B, the punching process uses a punching punch 533, a punching die 534, and a blank holder 539. In the burring process, in a state where the metal plate 520 is held by the die 534 and the blank 539, the punch 533, the die 534, and the blank 539 are moved relatively close to each other, and the metal plate 520 is placed. The peripheral portion of the pre-drilled hole is pushed into the recess of the die 534 together with the punch 533. As a result, the peripheral portion of the pre-drilled hole of the metal plate 520 is elongated in the pushing direction of the punch 533, and is also enlarged in the radial direction, and as a result, the cylindrical elongated flange, that is, the vertical wall portion 511 is formed.

The female screw 511b is machined on the inner circumferential surface of the cylindrical vertical wall portion 511 thus formed by, for example, tapping (not shown), whereby the screw hole 511 can be formed in the metal plate 520.

As for the screw hole of the metal plate, as shown in Patent Document 1, various types have been proposed so far. The frame proposed in Patent Document 1 has a screw hole formed in the second sheet metal member of the constituent member. The screw hole of the second sheet metal member has a first flat plate portion and a second flat plate portion which are formed so that the end edges of the sheet metal members are folded and opposed to each other. The screw hole of the second sheet metal member further includes a first cylindrical portion and a second cylindrical portion. The first cylindrical portion protrudes from the first flat plate portion into a cylindrical shape and has a screwing portion on the inner peripheral surface. The cylindrical portion protrudes from the second flat plate portion into a cylindrical shape and has a screw portion on the inner peripheral surface, and is arranged in line with the first cylindrical portion. According to the second sheet metal member, since the female screw is formed as the screwing portion on the inner circumferential surface of the first cylindrical portion and the second cylindrical portion, the axial direction of the contact with the male screw is long, and the tightness can be ensured. Solid torque.

Further, Patent Document 2 discloses a structure in which a first thin plate in which a first cylindrical portion is formed and a second thin plate in which a second cylindrical portion is formed are laminated, and the first tubular portion is coaxially embedded. After the inside of the second cylindrical portion, the self-tapping screw is screwed to the inner circumferential surface of the first cylindrical portion from the second thin plate side, whereby the first thin plate is consolidated to the first thin plate.

Advanced technical literature Patent literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 2011-214802

Patent Document 2 Japanese Patent Laid-Open Publication No. 2012-241839

Summary of invention

In the screw hole of the conventional metal plate 510 shown in Fig. 11, a female screw 511b is formed on the inner circumferential surface of the vertical wall portion (elongated flange) 511 which is formed by punching. The screw hole 511 which is formed by the burr processing is reduced in thickness with respect to the metal plate which is required to be lightweight for use in home electric appliances or automobile parts, and the fixing force of the male screw is lowered. Further, due to the deformation of the screw hole 511, the screw hole of the screw hole 511 and the screw of the male screw 550 do not engage, that is, the screw hole 511 is broken.

Moreover, in the above-mentioned Patent Document 1, there is proposed a structure in which the screw holes have a first flat plate portion and a second flat plate portion which are disposed to face each other, and the first flat plate portion and the second flat plate portion are respectively provided with screws. The cylindrical part of the joint. According to this configuration, it has been described that the length of the female screw that is in contact with the male screw is long in the axial direction, and the tightening torque can be secured. When the screw hole is formed, the pre-drilling is performed on the first flat plate portion, and then the burring process is performed. Thereby, the cylindrical portion is provided, and the pre-drilled hole is drilled in the second flat plate portion, and the burring process is performed. Here, the cylindrical portion is provided, and thereafter, the first flat plate portion is folded over to be superposed on the second flat plate portion, and further, a female screw is required to be processed. Thus, the processing requires six steps, and the number of processing is greatly increased. Further, when the first flat plate portion is folded over to overlap the second flat plate portion, the centers of the two cylindrical portions are required to coincide with each other, and high bending accuracy is required. Because of this, when it is metal When the sheet processing is described in the screw hole of Patent Document 1, there is a problem that the processing cost is greatly increased.

In the above-mentioned Patent Document 2, the paragraph number [0014] describes that "the second cylindrical portion is pressed by the first tubular portion in the radial direction, so that the thin plates are not loosened and the screws are firmly fixed. The member is fixed to have no gap between the first tubular portion and the second tubular portion, thereby preventing the relative positional deviation between the first thin plate and the second thin plate from being targeted.

In this configuration, when the difference between the inner diameter of the second tubular portion and the outer diameter of the first tubular portion is large, even if the first tubular portion is expanded radially outward, the second cylinder cannot be completely crimped. As a result, there is a flaw in the above effects. Therefore, in order to obtain sufficient consolidation force, it is preferable to make the above-described dimensional difference (gap size) small to some extent, but it is difficult to perform the operation of embedding the first cylindrical portion in the second cylindrical portion, and it is not correct, as the case may be. The ground is fitted, but there is still a mistake in screwing into the self-tapping screw. At this time, of course, the first thin plate and the second thin plate cannot be reliably fixed. Moreover, the screw holes are generally not only provided in one place but in multiple places, so it is undeniable that the probability of causing such work is not low. Therefore, the configuration of Patent Document 2 is not necessarily sufficient from the viewpoint that a sufficient consolidation force can be surely obtained.

The present invention has been made in view of the above circumstances, and an object of the invention is to provide a metal plate with a screw hole which can reduce the increase in processing cost and which is excellent in the fixing force of the screw hole and the male screw when the thin plate is formed, and can prevent the screw hole from being damaged. A frame for a metal plate with a screw hole and a method for manufacturing a metal plate with a screw hole.

In order to solve the above problems, the inventors of the present invention have analyzed the reduction of the fixing force of the screw caused by the thinning of the metal plate as illustrated in Fig. 11, and have obtained the following main causes of (a) to (d). .

(a) In the burr processing, the thickness of the root portion of the vertical wall portion 511 is reduced as the cylindrical vertical wall portion 511 is formed. Further, the "root portion" means a portion 511a of the vertical wall portion 511 which is connected to the metal body 513 as shown by a two-dot chain line in Fig. 11.

(b) Since the groove is machined to the root portion which is thinned by the thickness reduction of the above (a), the thickness is extremely thin.

(c) The plate is extremely thin and elastically deformed, and the fixing force is lowered. Further, when the male screw 550 is screwed in (locked in), plastic deformation occurs at a very thin plate thickness, and the screw hole 511 is broken or broken.

(d) The cylindrical vertical wall portion 511 is plastically deformed in the diameter expansion direction, and the screw having the screw hole 511 is in contact with the screw of the male screw 550, during the screwing operation or the unscrewing operation of the sun screw 550. The area where the area is reduced. At this time, the consolidation force is lowered, and the screw hole 511 is broken.

As a result of the review, the inventors of the present invention thought that the screw hole is configured as a cylindrical outer wall portion that rises from the metal plate and a cylindrical inner wall portion that is folded from the outer wall portion to the inner side. The double wall further has a female thread formed on the inner circumferential surface of the inner wall portion. Thereby, even when the thickness of the metal plate is made thin, the screw hole and the male screw are excellent in the fixing force, and the screw hole can be prevented from being damaged.

Further, the inventors of the present invention have conceived that the other aspect of the screw hole is configured such that the cylindrical inner wall portion rises from the metal plate and is folded from the inner wall portion to The double wall of the cylindrical outer wall portion formed on the outer side further forms a female thread on the inner circumferential surface of the inner wall portion, and this structure can obtain substantially the same effect.

The present invention has been completed based on the above findings, and the gist thereof is shown below.

(1) One aspect of the present invention is a metal plate having a screw hole, which is a metal plate having a screw hole, the screw hole having a cylindrical outer wall portion rising from one side of the metal plate, and from the foregoing An end edge of the outer wall portion is folded over to a cylindrical inner wall portion inside the outer wall portion, and a female screw is formed on an inner circumferential surface of the inner wall portion.

(2) In the metal plate with the screw hole as in the above (1), the front end of the inner wall portion and the other surface of the metal plate may be in the same plane.

(3) In the metal plate with the screw hole as in the above (1), the following structure may be employed, wherein the inner wall portion is in a state where the male screw is not screwed to the female screw of the screw hole. The outer circumferential surface is spaced apart from the inner circumferential surface of the outer wall portion, and at least a portion of the outer circumferential surface of the inner wall portion abuts the outer wall in a state where the male screw is screwed to the female screw of the screw hole. The aforementioned inner circumference of the Ministry.

(4) In the case of the metal plate with the screw hole attached to the above (3), the front end of the inner wall portion and the other surface of the metal plate may be in the same plane.

(5) Another aspect of the present invention is a metal plate with a screw hole, which is a metal plate having a screw hole; the screw hole has a cylindrical inner wall portion rising from one side of the metal plate and An end edge of the inner wall portion is folded over to a cylindrical outer wall portion on the outer side of the inner wall portion, and a female screw is formed on an inner circumferential surface of the inner wall portion.

(6) Still another aspect of the present invention is a housing comprising a metal plate having a screw hole, a member having a through hole, and the screw hole inserted into the through hole to insert the metal plate and the foregoing A male screw having a member in which a through hole is coupled; the metal plate is a metal plate having a screw hole as in any one of the above (1) to (5).

(7) A further aspect of the invention, the method of manufacturing the metal plate with the screw hole according to any one of the above (1) to (4), comprising the step of: forming the outer wall portion on the metal plate And a circular plate portion connected to the inner side of the outer wall portion; a pre-drilled hole is drilled in a center of the circular plate portion; and the circular plate portion drilled with the pre-drilled hole is bent to an inner side of the outer wall portion to form the foregoing The inner wall portion; the female inner thread is processed on the inner circumferential surface of the inner wall portion formed by the inner wall portion.

(8) In the method of manufacturing a metal plate having a screw hole as described in the above (7), in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness t (mm), A punch that satisfies the shoulder size of the radius R (mm) of the following formula (a).

0.5≦R/t≦1.0 Equation (a)

(9) In the method of manufacturing a metal plate with a screw hole as in the above (7), in the step of drilling the aforementioned pre-drilled hole in the metal plate having a thickness dimension t (mm), the pre-drilling may be performed The radius r (mm) of the pre-drilled hole is drilled to satisfy the following formula (b).

0.5≦r/t≦1.2 Equation (b)

(10) In the method of manufacturing a metal plate with a screw hole as described in the above (7), the outer wall portion is formed by the metal plate having a thickness t (mm) and In the step of the circular plate portion, a punch having a shoulder size satisfying the radius R (mm) of the following formula (a) may be used, in the step of drilling the aforementioned pre-drilled hole of the metal plate, the pre-drilling The hole drilling is such that the radius r (mm) of the aforementioned pre-drilled hole satisfies the following formula (b).

0.5≦R/t≦1.0 Equation (a)

0.5≦r/t≦1.2 Equation (b)

(11) A method of manufacturing a metal plate with a screw hole according to any one of the above (1) to (4), comprising an opening step, an outer wall portion, and a disk portion forming step a step of forming the inner wall portion and a processing step of drilling the pre-drilled hole in the metal plate; the step of forming the outer wall portion and the circular plate portion forming the outer wall portion concentrically with the pre-drilled hole, and connecting to the outer wall a circular plate portion on the inner side of the portion; the inner wall portion forming step of bending the disk portion to the inner side of the outer wall portion to form the inner wall portion; and the processing step of processing the yin on the inner circumferential surface of the inner wall portion Thread.

(12) In the method of manufacturing a metal plate having a screw hole as described in the above (11), in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness t (mm), A punch that satisfies the shoulder size of the radius R (mm) of the following formula (a).

0.5≦R/t≦1.0 Equation (a)

(13) In the method of manufacturing a metal plate with a screw hole as in the above (11), in the step of drilling the aforementioned pre-drilled hole in the metal plate having a thickness dimension t (mm), the pre-drilling may be performed The radius r (mm) of the aforementioned pre-drilled hole after the step of forming the aforementioned circular plate portion satisfies the following formula (b).

0.5≦r/t≦1.2 Equation (b)

(14) In the method of manufacturing a metal plate having a screw hole as described in the above (11), the step of forming the outer wall portion and the disk portion by the metal plate having a thickness t (mm) may be used. A punch that satisfies the shoulder size of the radius R (mm) of the following formula (a) is a step of drilling the pre-drilled hole into the circular plate portion in the step of drilling the aforementioned pre-drilled hole in the metal plate The radius r (mm) of the aforementioned pre-drilled hole satisfies the following formula (b).

0.5≦R/t≦1.0 Equation (a)

0.5≦r/t≦1.2 Equation (b)

The metal plate with the screw hole according to the above aspect (1) to (4) of the present invention has a double wall structure having an outer wall portion and an inner wall portion which is folded from the outer wall portion to the inner side. According to this configuration, when the male screw is screwed to the female screw of the inner wall portion, the inner wall portion is pushed to the outer side in the radial direction by the pressing force of the male screw, but can be restrained by being supported by the wall portion located at the outer periphery thereof. Excessive deformation of the inner wall. As a result, it is possible to prevent a decrease in the fixing force due to breakage of the screw hole or excessive expansion of the inner wall portion.

Further, from the viewpoint of the consolidation force, the elastic effect of the diameter reduction direction is always applied to the inner wall portion because the inner wall portion is folded over to the inner side of the outer wall portion to form a springback effect. As a result, since the male screw is screwed into the female screw of the inner wall portion, the male screw is pressed and the female screw is pressed to be in close contact with each other, so that a high consolidation force without loosening can be ensured.

Further, in view of the prevention of breakage, since the outer wall portion does not form a conventional female thread, it is possible to prevent the root portion of the outer wall portion from being thinner and easily broken due to the formation of the female thread. Also, although the root portion of the inner wall portion is shaped It has a female thread, but it is not easily damaged because it forms a double wall structure surrounded by an outer wall. In this way, since each of the bent portions of the screw holes can ensure high strength, damage can be prevented.

As described above, according to the metal plate with the screw hole in this aspect, even if the plate thickness is small, the screw hole and the male screw are excellent in the fixing force, and the screw hole can be prevented from being damaged.

The metal plate with the screw hole according to the aspect of the above (5) has a double wall structure having an inner wall portion and an outer wall portion which is folded from the inner wall portion to the outer side. According to this configuration, when the male screw is screwed to the female screw of the inner wall portion, the inner wall portion is pushed to the outer side in the radial direction by the pressing force of the male screw, but can be restrained by being supported by the wall portion located at the outer periphery thereof. Excessive deformation of the inner wall. As a result, it is possible to prevent a decrease in the fixing force due to breakage of the screw hole or excessive expansion of the inner wall portion.

Since the frame body according to the above aspect (6) is provided with the above-mentioned metal plate with the screw hole, the screw hole and the male screw are excellent in the fixing force, and the screw hole can be prevented from being damaged. Therefore, it can prevent the screw that has been screwed in from loosening.

As described above, in the method of manufacturing the metal plate with the screw holes as described in the above (7) to (14), the screw hole having excellent fixing force and preventing breakage can be processed on the metal plate. Moreover, the number of processing and the increase in processing cost can be reduced.

10,100,110,200,510‧‧‧Metal plates with screw holes

10a, 513‧‧‧ body of metal plate

10x‧‧‧ surface

10y‧‧‧The other side of the metal plate

12,212‧‧‧ screw holes

12a, 212a‧‧‧External wall

12a1‧‧‧The root part of the outer wall

12a2‧‧‧The other end

12b, 212b‧‧‧ Inner Wall

12b1, 212b1‧‧‧ female thread

12b3‧‧‧ front end of the inner wall

12c‧‧‧ the root part of the inner wall

20,220‧‧‧Metal plates

20a‧‧‧Outer wall

20b‧‧‧round board

20b1‧‧‧Pre-drilling

31‧‧‧Drilling punch

32‧‧‧Drilling die

35‧‧‧Pressure punch

36‧‧‧Pressure die

36a‧‧‧Binder clip

37‧‧‧Reaming punch

38‧‧‧Reaming die

39‧‧ ‧ ping clip

40‧‧‧ Screw tap

50,550‧‧‧yang screws

51‧‧‧Members (metal plates)

51a, 551a‧‧‧through holes

70‧‧‧ frame

511‧‧‧Vertical wall (screw hole)

511a‧‧‧Parts connected to the main body

511b‧‧‧ female thread

520‧‧‧Metal plates for processing objects

531‧‧‧Drilling punch

532‧‧‧Drilling die

533‧‧‧With the punch

534‧‧‧Pressure die

539‧‧‧Binder clips

551‧‧‧Metal sheet

A‧‧‧ (Figure 1)

A‧‧‧The point at which the female thread begins to plastically deform (Figure 10)

B‧‧‧ intersection

CL‧‧‧Center axis of the screw hole

L, L’‧‧‧ Straight line

L1, L2‧‧‧ length dimension of the inner wall

O‧‧‧From the fixed state to the point of increase

R‧‧‧

r‧‧‧Pre-drilling radius

T‧‧‧ plate thickness

X‧‧‧ arrows

1 is a view schematically showing a screw hole of a metal plate with a screw hole according to a first embodiment of the present invention, and is a longitudinal cross-sectional view when viewed in a cross section of a central axis including a screw hole.

Fig. 2 is an enlarged view of a portion A of Fig. 1 and is a view before being screwed into a self-tapping screw.

Fig. 3 is an enlarged view of a portion A of Fig. 1 and is a view after screwing in a self-tapping screw.

Fig. 4 is an exploded perspective view showing the casing of the embodiment.

Fig. 5A is a view for explaining a method of manufacturing a metal plate with a screw hole according to the embodiment, and is a cross-sectional view showing a step of forming an outer wall portion in the processing flow.

Figure 5B is a cross-sectional view showing the drilling step following the forming step of the outer wall portion of the processing flow.

Fig. 5C is a cross-sectional view showing the step of forming the inner wall portion following the drilling step of the processing flow.

Fig. 5D is a cross-sectional view showing the step of forming the female thread after the forming step of the inner wall portion of the processing flow.

Fig. 6A is a view showing a modification of the method of manufacturing a metal plate with a screw hole according to the embodiment, and showing a cross-sectional view of a drilling step in the machining flow.

Fig. 6B is a cross-sectional view showing the step of forming the outer wall portion after the drilling step in the processing flow of the modification.

Fig. 6C is a cross-sectional view showing the step of forming the inner wall portion subsequent to the step of forming the outer wall portion in the processing flow of the modification.

Fig. 6D is a cross-sectional view showing the step of forming the female thread after the step of forming the inner wall portion in the processing flow of the modification.

FIG. 7 is a view schematically showing a screw hole of a metal plate with a screw hole according to a second embodiment of the present invention, and is a longitudinal cross-sectional view when viewed in a cross section including a central axis of the screw hole.

Figure 8 is a view schematically showing a screw hole with a third embodiment of the present invention; The figure of the screw hole of the metal plate is a longitudinal cross-sectional view when viewed in a cross section including the central axis of the screw hole.

FIG. 9 is a view schematically showing a screw hole of a metal plate with a screw hole according to a fourth embodiment of the present invention, and is a longitudinal cross-sectional view when viewed in a cross section including a central axis of the screw hole.

Fig. 10 is a graph showing the relationship between the angle of the male screw and the tightening torque of the experiment for evaluating the fixing force of the screw hole, and the relationship between the rotation angle of the male screw and the tightening torque.

Fig. 11 is a cross-sectional view schematically showing a screw hole of a conventional metal plate with a screw hole.

Fig. 12A is a view showing an example of a processing flow of a screw hole of a conventional metal plate with a screw hole, and is a cross-sectional view showing a drilling step in the machining flow.

Figure 12B is a cross-sectional view showing the rinsing step of the processing flow following the drilling step.

Form for implementing the invention

Hereinafter, each embodiment of the method for manufacturing a metal plate with a screw hole, a frame having the metal plate with the screw hole, and a metal plate with a screw hole according to the present invention will be described with reference to the drawings. Further, the metal plate with the screw holes of the present invention can be applied to any of the electroless plated steel and the plated steel plate.

First embodiment

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing a gold with a screw hole according to a first embodiment of the present invention; The diagram of the screw hole of the sub-plate 10 is a longitudinal cross-sectional view when viewed in a cross section including the center axis CL of the screw hole. Further, in Fig. 1, in order to understand the structure, in addition to the metal plate 10 with the screw holes, the male screw 50 and the metal plate 51 having the through hole 51a are also shown by imaginary lines.

As shown in Fig. 1, the screw hole 12 of the metal plate 10 having the screw hole (hereinafter also referred to as the metal plate 10) of the present embodiment has an outer wall portion 12a and an inner wall portion 12b. The outer wall portion 12a is formed in a cylindrical shape that rises substantially perpendicularly from the body 10a of the metal plate 10. In other words, the root portion 12a1 of the cylindrical outer wall portion 12a at one end in the axial direction is connected to the body 10a, and its central axis CL is perpendicular to the surface 10x of the body 10a. The other end 12a2 of the outer wall portion 12a in the direction along the central axis CL is connected to the root portion 12c of the inner wall portion 12b. The inner wall portion 12b is formed in a cylindrical shape that is disposed coaxially with the outer wall portion 12a, and is formed by folding the upper end (the other end 12a2) of the outer wall portion 12a to the inner side. Further, a female screw 12b1 is formed on the inner circumferential surface of the inner wall portion 12b.

In the screw hole 12 of the metal plate 10 with the screw hole of the embodiment, even if the thickness t is thin, the thickness of the inner wall portion 12b at the root portion 12c can be reduced, and the fixing force of the screw hole 12 can be improved. Also, the screw hole 12 can be prevented from being damaged. The reason why the thickness of the root portion 12c of the inner wall portion 12b is reduced in the metal plate 10 having the screw hole in the present embodiment will be described later. Here, the "root portion 12c of the inner wall portion 12b" as indicated by a dotted line in Fig. 1 means a portion connected to the other end 12a2 of the outer wall portion 12a.

The screw hole 12 of the metal plate 10 with a screw hole according to the present embodiment has a double wall structure having an outer wall portion 12a and an inner wall portion 12b obtained by folding the outer wall portion 12a. Thereby, the screwing operation of the sun screw 50 or screwing In the loosening operation, even if the inner wall portion 12b receives the force in the diameter increasing direction by the pressing of the male screw 50, the outer wall portion 12a can be supported from the periphery, so that the inner wall portion 12b can be prevented from being excessively deformed in the diameter expanding direction to prevent solidification. The lowering of the clamping force and the breakage of the screw hole 12.

The screw hole 12 of the metal plate 10 having the screw hole according to the present embodiment is described as a manufacturing method to be described later, and is formed into a contact between the outer peripheral surface of the inner wall portion 12b and the inner peripheral surface of the outer wall portion 12a during the bending process. By the bounce, the formed inner wall portion 12b is slightly deformed in the diameter reducing direction. Therefore, in a state where the male screw 50 is not screwed to the female screw 12b1 of the screw hole 12, the outer peripheral surface of the inner wall portion 12b is spaced apart from the inner peripheral surface of the outer wall portion 12a, and the male screw 50 is screwed to the screw. In the state of the female screw 12b1 of the hole 12, at least a part of the outer peripheral surface of the inner wall portion 12b is formed to abut against the inner peripheral surface of the outer wall portion 12a. This structure will be described in further detail with reference to FIGS. 2 and 3.

First, as shown in FIG. 2, in the state before the male screw 50 is screwed into the screw hole 12, the springback generated after the screw hole 12 is formed by the bending process, the front end portion 12b3 of the inner wall portion 12b and the root portion of the outer wall portion 12a Part 12a1 is slightly spaced apart. Therefore, a slight gap is formed between the outer peripheral surface of the inner wall portion 12b and the inner peripheral surface of the outer wall portion 12a.

Next, as shown in FIG. 3, in a state where the male screw 50 is screwed into the screw hole 12, the inner wall portion 12b which has withstood the pressing force of the male screw 50 is elastically deformed in the diameter-expanding direction, and as a result, The outer peripheral surface of the wall portion 12b abuts against the inner peripheral surface of the outer wall portion 12a, and the gap disappears. Therefore, as described above, the outer wall portion 12a prevents the deformation of the inner wall portion 12b from being restricted, and in addition to this, the inner wall portion 12b exerts a restoring force that can return to the state of Fig. 2 by the rebound. Because of this resilience, as shown As indicated by the arrow X of the arrow 3, the inner wall portion 12b is given the potential energy of the sun-facing screw 50, so that the female screw 12b1 and the male screw 50 are kept in close contact with each other. Therefore, the fixing force between the screw hole 12 and the male screw 50 can be further increased to prevent the male screw 50 from coming loose.

As described above, the screw hole 12 of the metal plate 10 with the screw hole of the present embodiment has the cylindrical outer wall portion 12a which is vertically raised from one side 10x of the metal plate 10, and is folded from the upper edge of the outer wall portion 12a. The cylindrical inner wall portion 12b on the inner side of the outer wall portion 12a is formed with a female screw 12b1 on the inner circumferential surface of the inner wall portion 12b.

According to this configuration, even if the thickness t of the metal plate 10 having the screw holes is made thin, the fixing force of the screw holes 12 and the male screws 50 is excellent, and the breakage of the screw holes 12 can be prevented. Further, since the screw hole 12 is formed into a body by a forming process, it is not necessary to perform a complicated operation such as welding, and the processing cost is not greatly increased.

Further, in the metal plate 10 with the screw hole in the present embodiment, the front end 12b3 of the inner wall portion 12b and the other surface 10y of the metal plate are flush with each other.

According to this configuration, when the flat surface of the other surface 10y of the mounting surface of the metal plate 10 to which the screw hole is attached is required to have no unevenness, the degree of unevenness of the formation of the screw hole 12 can be minimized. And it is ensured that the length dimension of the female thread 12b1 is the largest. Therefore, it is possible to obtain a metal plate 10 with screw holes and a combination of aesthetic and consolidation forces.

Next, the casing of this embodiment will be described below using Figs. 1 and 4 .

As shown in FIG. 4, the frame body 70 of the present embodiment has the above-mentioned metal plate 10 with a screw hole, and a member (metal plate) 51 having a through hole 51a, which is inserted into The screw hole 12 is screwed into the through hole 51a, and the male screw 50 between the metal plate 10 and the member 51 to which the screw hole is attached is joined. 4 is an exploded perspective view showing a principal part of the screw hole 12 in a state in which the screw plate 12 is screwed into the screw hole 12 and the metal plate 10 with the screw hole and the member 51 are joined, as shown in FIG.

According to the frame body 70 of the present embodiment, since the metal plate 10 having the screw holes has the above-described structure, the screw holes 12 and the male screws 50 have excellent fixing force, and the screw holes 12 can be prevented from being damaged. Further, it is also a frame 70 that can prevent the male screw 50 that is screwed in from coming loose. Further, as the casing 70, an indoor unit or an outdoor unit of the air conditioner, a casing of the power conversion apparatus, and the like can be exemplified.

Further, in Fig. 1, the member 51 which is a metal plate having the through hole 51a is attached to the front end 12b3 side of the inner wall portion 12b, but the present invention is not limited to this configuration, and the member 51 may be attached to the root of the inner wall portion 12b. Part 12c side structure. That is, in Fig. 1, the metal plate 10 with the screw holes may be opposed to the upper and lower surfaces of the member 51. In addition, the "inner end portion 12b front end 12b3" refers to an end portion located at a position facing the root portion 12c in the direction along the center axis line CL. Further, the member 51 is not limited to a metal plate, and includes an attachment member having a through hole or the like.

Next, a method of manufacturing the metal plate 10 with screw holes according to the present embodiment will be described. In the present embodiment, after the outer wall portion forming step, the drilling step is performed, and a modification (described later) of the outer wall portion forming step after the drilling step may be employed.

5A to 5D are schematic views showing a processing flow of a method of manufacturing a metal plate according to the embodiment, and FIG. 5A is a view showing a step of forming an outer wall portion. 5B shows the drilling step, FIG. 5C shows the inner wall forming step, and FIG. 5D shows the female thread forming step.

First, in the outer wall portion forming step, the outer wall portion 20a and the disc portion 20b connected to the outer wall portion 20a are formed in the metal plate 20 (raw material) to be processed. The cylindrical outer wall portion 20a is connected to the body of the metal plate 20 at one end of the central axis CL direction, and rises from the metal plate 20 such that its central axis CL is perpendicular to the surface of the metal plate 20. The inner side of the other end of the outer wall portion 20a in the direction of the central axis CL is connected to the disc portion 20b.

The outer wall portion 20a and the disk portion 20b of such a shape can be formed by press working or drawing processing using a punch and a die. In the press working, as shown in Fig. 5A, a blank holder 36a is used in addition to the press punch 35 and the press punch 36. In a state in which the metal plate 20 is held by the blank holder 36a and the die 36 from the front surface and the back surface thereof, the punch 35, the die 36, and the blank holder 36a are relatively moved, and one portion of the metal plate 20 is combined with the punch 35. Push into the die 36. Thereby, the cylindrical outer wall portion 20a and the disc portion 20b are formed on the metal plate 20.

In the subsequent drilling step, a pre-drilled hole is drilled in the center of the circular plate portion 20b. That is, as shown in FIG. 5B, the drilling hole 31 and the drilling die 32 are used to perform the drilling of the shearing process, and the pre-drilled hole 20b1 is drilled in the disk portion 20b. Drilling can also be carried out by using a drilling machine or a laser cutting machine.

In the subsequent inner wall portion forming step, the disc portion 20b of the pre-drilled hole 20b1 is drilled and bent, and the inner wall portion 12b which is folded over to the inner side of the outer wall portion 20a (12a) is formed. The bending of the disc portion 20b can be performed by a so-called reaming process.

That is, in the hole expanding process, the punching punch 37, the punching die 38, and the blank clip 39 shown in Fig. 5C can be used. That is, the punch 37, the die 38, and the blank holder 39 are relatively moved while the metal plate 20 is held by the die 38 and the blank holder 39 from the front surface and the back surface thereof. At this time, the punch 37 is pushed into the pre-drilled hole 20b1. In this manner, when the disc portion 20b of the metal plate 20 is pushed into the inner side of the outer wall portion 20a together with the punch 37, the disc portion 20b is elongated in the pushing direction of the punch 37, and the surface is also enlarged in the radial direction. As a result, the inner wall portion 12b (20b) having a cylindrical shape and folded from the outer wall portion 12a (20a) to the inner side is formed. At this time, the outer peripheral surface of the inner wall portion 12b is formed to contact the inner peripheral surface of the outer wall portion 12a, and since the inner wall portion 12b is slightly deformed in the diameter reducing direction by the rebound, a gap as shown in FIG. 2 is generated.

In the subsequent thread cutting step, the female thread 12b1 is machined on the inner circumferential surface of the formed inner wall portion 12b. The processing method of the female thread 12b1 is not particularly limited, and as shown in FIG. 5D, the female thread 12b1 can be machined by the tapping 40. As described above, according to the manufacturing method of the present embodiment, the metal plate 10 having the screw hole, that is, the screw hole 12 having the outer wall portion 12a and the inner wall portion 12b of a portion of the outer wall portion 12a can be processed. Metal plate 20.

According to the manufacturing method of the present embodiment, the thickness reduction of the root portion of the screw hole can be reduced as compared with the conventional method of forming the screw hole by the edge processing as described with reference to Fig. 11 . That is, in the conventional manufacturing method, as shown in FIG. 12B, in the state of the edge processing, in the state where the metal plate 520 is held by the die 534 and the blank holder 539, the portion around the pre-drilled hole of the metal plate 520 is The punch 533 is pushed into the recess of the die 534 together and deformed, whereby the vertical wall portion 511 is formed. At this time, due to the deformation of the metal plate 520 around the pre-drilled hole The root portion 511a is close to the portion held by the die 534 and the blank holder 539, so that a very large tensile stress is generated at the root of the vertical wall portion 511, and as a result, the thickness is reduced.

On the other hand, as shown in Fig. 5C, in the inner wall portion forming step, the disk portion 20b is pushed together with the punch 37 into the outer wall portion 20a (12a) while the metal plate 20 is held by the die 38 and the blank holder 39. The inside is deformed, whereby the inner wall portion 12b is formed. At this time, in the metal plate 20, the deformed disk portion 20b and the portion between the punch 38 and the blank holder 39 are present with the outer wall portion 12a. Thereby, the tensile stress generated in the root portion 12c of the inner wall portion 12b can be relieved, and as a result, the thickness reduction of the root portion 12c can be reduced as compared with the conventional root portion 511a (see Fig. 11).

Therefore, according to the manufacturing method of the present embodiment, the fixing force of the formed screw hole 12 and the male screw 50 can be improved, and the screw hole 12 can be prevented from being damaged. Further, since the screw hole 12 has a double wall structure of the outer wall portion 12a and the inner wall portion 12b, deformation of the inner wall portion 12b in the diameter expansion direction can be prevented, and the reduction of the fixing force due to the deformation and the breakage of the screw hole 12 can be prevented. . Further, since the inner wall portion 12b is formed by bending the disc portion 20b, when the male screw 50 is screwed into the screw hole 12, the restoring force due to the springback of the inner wall portion 12b occurs, and the inner wall portion 12b is adhered to Male screw 50. Thereby, the fixing force of the screw hole 12 can be further improved, and the screwing of the male screw 50 can be more reliably prevented from coming loose.

In the present embodiment, since the screw holes 12 can be formed in four steps of forming the outer wall portion, drilling, forming the inner wall portion, and forming the female thread, the number of the machining holes can be reduced as compared with the conventional screw hole proposed in the above Patent Document 1. increase. Again, the above four steps do not require high processing accuracy. Thus, according to this embodiment The manufacturing method can reduce the increase in processing cost as compared with the screw hole proposed in the above Patent Document 1.

As a method of manufacturing the metal plate with the screw hole of the present invention, a modification other than the above description may be employed as shown in FIGS. 6A to 6D.

Fig. 6A shows a drilling step, Fig. 6B shows an outer wall portion forming step, Fig. 6C shows an inner wall portion forming step, and Fig. 6D shows a female thread forming step. In the present modification, when the screw hole 12 is formed, first, in the drilling step, the pre-drilling hole is drilled. That is, as shown in FIG. 6A, the drilling punch 31 and the drilling die 32 are used to perform the drilling of the shearing process, and the pre-drilled hole 20b1 is drilled in the metal plate 20 to be processed. Drilling can also be done using a drilling machine or a laser cutting machine.

In the subsequent outer wall forming step, as shown in FIG. 6B, the cylindrical outer wall portion 20a and the disc portion 20b connected to the outer wall portion 20a are formed in the metal plate 20. The root portion of one end of the cylindrical outer wall portion 20a in the axial direction is connected to the metal plate 20, and rises from the metal plate 20 such that its central axis CL is perpendicular to the surface of the metal plate 20. Further, the inner side of the other end of the outer wall portion 20a along the direction of the central axis CL thereof is connected to the disc portion 20b. In the present modification, the outer wall portion 20a and the disc portion 20b are formed such that the pre-drilled hole 20b1 is concentric with the cylindrical outer wall portion 20a.

The formation of the outer wall portion 20a and the circular plate portion 20b can be formed by press working or drawing processing using a punch and a die. In the press working, a blank holder 36a is used in addition to the press punch 35 and the press punch 36 as shown in Fig. 6B. The metal plate 20 is configured such that the center of the pre-drilled hole 20b1 and the concave portion of the die 36 The center of the part is identical, and the metal plate 20 is held by the die 36 and the blank holder 36a. In this state, the punch 35, the die 36, and the blank holder 36a are relatively moved, and a part of the metal plate 20 is pushed into the die 36 together with the punch 35. Thereby, the cylindrical outer wall portion 20a and the disc portion 20b are formed in the metal plate 20. At this time, the pre-drill hole 20b1 is deformed to expand the diameter.

In the subsequent inner wall portion forming step, as shown in Fig. 6C, the formed circular plate portion 20b is bent, and the inner wall portion 12b which is folded from the outer wall portion 12a to the inner side is formed.

In the subsequent female thread forming step, as shown in Fig. 6D, the female thread 12b1 is machined on the inner peripheral surface of the inner wall portion 12b. The bending of the disk portion 20b is performed by a hole expanding process in the same manner as in the above embodiment. Further, the processing of the female thread 12b1 is not particularly limited as in the above embodiment, and for example, it can be processed by the tapping 40.

Further, in the manufacturing method of the above modification, the screw hole 12 having the outer wall portion 12a and the inner wall portion 12b may be formed in the metal plate 20. Further, in the present modification, when the inner wall portion forming step bends the disc portion 20b, the disc portion 20b deformed in the metal plate 20 and the portion held by the die 38 and the blank holder 39 are also present. The outer wall portion 12a. Therefore, the thickness of the root portion 12c of the inner wall portion 12b can be reduced, and as a result, the fixing force of the screw hole 12 can be improved, and the breakage of the screw hole 12 can be prevented.

Further, in the present modification, as in the above-described embodiment, since the obtained screw hole 12 has a double wall structure having the outer wall portion 12a and the inner wall portion 12b, the inner wall portion 12b can be prevented from being excessively expanded in the diameter expansion direction. The deformation is prevented, and the reduction of the fixing force caused by the same and the breakage of the screw hole 12 are prevented. Again, when When the male screw 50 is screwed into the screw hole 12, the inner wall portion 12b is brought into close contact with the male screw 50 by the springback. Thereby, the fixing force of the screw hole 12 is further improved, and the screwing of the male screw 50 can be prevented from coming loose.

In the present modification, the screw holes 12 can be formed by drilling, the outer wall portion forming, the inner wall portion forming, and the female screw forming in four steps. Therefore, compared with the conventional screw hole proposed in the above Patent Document 1, the increase in the number of machining can be suppressed. Also, high processing accuracy is not required for the above four steps. Therefore, the present modification can reduce the increase in processing cost as compared with the screw hole proposed in the above Patent Document 1.

In the present modification, the outer wall portion forming and the inner wall portion forming step can be performed by the same apparatus. In this case, the increase in the number of processing can be further suppressed. Specifically, in FIG. 6B, the reaming punch 37 (not shown) shown in FIG. 6C is disposed to face the pressing punch 35. After the outer wall portion 20a (12a) and the disk portion 20b are formed by the pressing punch 35 and the punching die 36, the inner wall portion 12b is formed by the reaming punch 37 immediately.

In the first embodiment and its modification described above, in the outer wall portion forming step (see Figs. 5A and 6B), it is preferable to use the radius of the die 36 and the shoulder when forming the outer wall portion 20a (12a) and the disk portion 20b. R (mm) satisfies the punch 35 of the following formula (1). Further, in the drilling step (refer to FIG. 5B, FIG. 6A), it is preferable that the pre-drilled hole is a radius r (mm) of the pre-drilled hole before the forming of the inner wall portion of the subsequent inner wall portion forming step satisfies the following formula (2). Further, t shows the plate thickness (mm) of the metal plate 20.

0.5≦R/t≦1.0 Equation (1)

0.5≦r/t≦1.2 Equation (2)

Here, the "radius of the shoulder" of the punch 35 means joining and forming The outer peripheral surface of the punch 35 where the outer wall portion 20a (12a) of the metal plate 20 abuts and the radius of the R portion of the front end surface of the punch 35 abutting on the formed disk portion 20b (see FIGS. 5A and 6B). Further, "the radius of the pre-drilled hole before the inner wall portion of the inner wall portion forming step is formed", specifically, in the above embodiment, corresponds to the pre-drilled hole 20b1 drilled in the drilling step shown in Fig. 5B. The radius, in the above-described modification, corresponds to the radius of the pre-drill hole 20b1 in the state in which the outer wall portion forming step is deformed in the diameter expansion direction as shown in Fig. 6B after the drilling step.

When the radius R (mm) of the shoulder portion of the punch 35 is less than 0.5 × t (mm) in the outer wall portion forming step, the punch 35 is caught in the R portion (curved portion) that connects the outer wall portion 20a (12a) and the disc portion 20b. In part, there is a case where the thickness is reduced to the phenomenon of breakage, resulting in a defective product, and the manufacturing yield is lowered. On the other hand, when the radius R (mm) of the shoulder portion of the punch 35 is larger than 1.0 × t (mm), the inner wall portion forming step connects the outer wall portion 20a (12a) and the R portion of the disc portion 20b ( The bent portion is not sufficiently bent, and the outer wall portion 20a (12a) is collapsed toward the inner wall portion 12b side, and as a result, there is still a defect in the product.

Further, when the radius r (mm) of the pre-drilled hole 20b1 is less than 0.5 × t (mm), the inner wall portion forming step deforms the peripheral portion of the pre-drilled portion 20b1 when the circular plate portion 20b is bent The power is too big. Thereby, the R portion (curved portion) connecting the outer wall portion 20a (12a) and the main body of the metal plate 20 is deformed, and as a result, the inner wall portion 12b and the outer wall portion 20a (12a) cannot be formed, and the product is defective. The yield is reduced. On the other hand, when the radius r (mm) of the pre-drilled hole is larger than 1.2 × t (mm), the inner wall portion 12b formed by the inner wall portion forming step has a small height and a small number of threads. Therefore, there is a possibility that the force of solidification with the male screw 50 cannot be obtained.

In the method of manufacturing a metal plate with a screw hole, a frame having the metal plate with the screw hole, and a metal plate with a screw hole, the material of the metal plate itself is not particularly limited.

The method for producing a metal plate with a screw hole according to the present invention is preferably a step of forming the inner wall portion, and a punch 37 having a tapered portion at the front end as shown in Figs. 5C and 6C is used. The reason for this is that, in the description of the prior art, the straight punching punch 533 shown in Fig. 12B is easily promoted by using the punch 37 having a tapered portion which is smaller as the outer diameter of the front end is smaller. The R portion (bending portion) connecting the outer wall portion 20a (12a) and the disc portion 20b is bent and deformed, and the collapse of the outer wall portion 20a (12a) can be suppressed.

Second embodiment

Hereinafter, a second embodiment of the present invention will be described with reference to Fig. 7 . In the description, the differences from the first embodiment will be mainly described, and the other points are the same as those in the first embodiment, and the description thereof will be omitted.

Fig. 7 is a view schematically showing a screw hole 12 of a metal plate 100 with a screw hole according to the present embodiment, and is a longitudinal sectional view corresponding to Fig. 3 when viewed in a cross section including a central axis CL of the screw hole 12.

The metal plate 100 with a screw hole according to the present embodiment has a length L1 of the inner wall portion 12b longer than that of the first embodiment. As a result, the front end 12b3 of the inner wall portion 12b protrudes from the aforementioned other surface 10y of the metal plate.

According to this configuration, for example, when the metal plate 100 with the screw holes is overlapped and the other metal plate 51 is aligned, as shown in FIG. 7, the protruding portion of the inner wall portion 12b is embedded in the other metal plate 51. In the through hole 51a, the alignment can be easily performed.

Further, since the length of the female screw 12b1 is longer than that of the first embodiment described above, the length of the portion screwed to the male screw 50 can be made longer, and the consolidation can be performed more reliably.

Third embodiment

Hereinafter, a third embodiment of the present invention will be described with reference to Fig. 8 . In the description, the differences from the above-described first embodiment will be mainly described, and the other points are the same as those in the first embodiment, and the description thereof will be omitted.

Fig. 8 is a view schematically showing a screw hole 12 of a metal plate 110 having a screw hole according to the present embodiment, and is a longitudinal sectional view corresponding to Fig. 3 when viewed in a cross section including a central axis CL of the screw hole 12.

The metal plate 10 with a screw hole according to the present embodiment has a length L2 of the inner wall portion 12b shorter than that of the first embodiment. As a result, the front end portion 12b3 of the inner wall portion 12b is located further inside than the other surface 10y of the metal plate. Therefore, when the screw is locked, a slight gap is formed between the surface of the other metal plate 51.

According to this configuration, for example, when the metal plate 10 with the screw hole is overlapped with the other metal plate 51 and then locked by the male screw 50, since the inner wall portion 12b is shorter than the first embodiment, The length of the portion where the male screw 50 is screwed is shortened. However, due to the aforementioned gap, when the male screw 50 is locked, the front end portion 12b3 of the inner wall portion 12b is allowed to be closer to the screw head of the male screw 50. Then, while the male screw 50 is locked, the male screw 50 pulls the inner wall portion 12b toward itself, and as a result, the cylindrical inner wall portion 12b is reduced in diameter. Thereby, the inner wall portion 12b tightly closes the male screw 50, and a high consolidation force can be secured.

Fourth embodiment

Hereinafter, a fourth embodiment of the present invention will be described with reference to Fig. 9 . In the description, the differences from the above-described first embodiment will be mainly described, and the other points are the same as those in the first embodiment, and the description thereof will be omitted.

Fig. 9 is a view schematically showing a screw hole 212 of a metal plate 200 with a screw hole according to the present embodiment, and is a longitudinal sectional view corresponding to Fig. 3 when viewed in a cross section including a central axis CL of the screw hole 212.

The metal plate 200 with the screw hole in the embodiment is a metal plate having a screw hole 212 having a cylindrical inner wall portion 212b rising from one side of the metal plate 220 and the end portion from the inner wall portion 212b. The cylindrical outer wall portion 212a is folded over to the outer side of the inner wall portion 212b, and a female screw 212b1 is formed on the inner circumferential surface of the inner wall portion 212b.

Although this configuration is different from the above-described first embodiment, the effect of springback of the inner wall portion 212b cannot be obtained, but the outer wall portion 212a can block the diameter expansion direction of the inner wall portion 212b when the male screw (not shown) is locked. Deformation. Therefore, since the excessive deformation of the inner wall portion 212b can be restricted, even if the thickness of the metal plate 220 is thin, the breakage of the screw hole 212 or the reduction of the fixing force can be prevented.

Further, the metal plate 200 with the screw holes of the present embodiment can also be used as a constituent element of the frame. In other words, a metal plate having a screw hole, a member having a through hole, and a frame in which the screw hole is inserted into the through hole and the metal plate is coupled to the member having the through hole is provided in the frame. As the aforementioned metal plate, the above-mentioned metal plate 200 with a screw hole can be used.

Example

In order to verify the effect of the present invention, the gold of the screw hole is attached to the present invention. In the manufacturing method of the slab, an screw hole was formed in the metal plate, and an experiment for evaluating the fixing force of the screw hole was performed.

The sample used was a steel plate having a thickness of 0.4 to 0.6 mm and a tensile strength of 270 MPa. In the method of manufacturing a metal plate with a screw hole according to the first embodiment described with reference to FIGS. 5A to 5D, the steel plate is machined with a screw hole having a nominal diameter of M3 in JIS B0205 (2001).

The outer wall portion forming step was carried out by a press working, and a wall portion 20a having a height of 1.4 mm was formed by using a press punch 35 having an outer diameter of 3.2 mm, a die 36 having a concave portion having an inner diameter of 4.6 mm, and a blank holder 36a. At this time, the shoulder radius R of the pressing punch 35 is changed. Further, the drilling step uses the drilling punch 31 and the drilling die 32 to perform the shearing process. At this time, the radius r of the pre-drill hole 20b1 is changed. The inner wall portion forming step is performed using a tapping punch 37 having a tapered tip end, a reaming die 38, and a blank holder 39. The reaming punch 37 uses a straight portion having a radius of 1.2 mm, and the front end corner portion of the tapered portion has a chamfer of 60° with respect to the central axis CL.

For comparison, according to the processing flow described using FIGS. 12A and 12B, a metal plate 10 with screw holes formed with screw holes formed in a metal plate by conventional punching was also fabricated (Experiment No. 1-1A, 2) -1A, 3-1A).

Further, for comparison, a metal plate (not shown) having a screw hole having the structure of Fig. 1 described in Patent Document 2 cited in the background of the invention (Experiment No. 1-1B, 2-) was also produced. 1B, 3-1B). This comparative example is described with reference to Fig. 1 shown in the first embodiment, that is, a structure in which the inner circumferential surface and the inner wall portion of the outer wall portion 12a are in a state in which the male screw 50 is screwed. The outer surface of 12b is still separated to create a considerable gap, and the circumference of the inner wall portion 12b It is supported by the outer wall portion 12a.

In each experiment, 20 metal plates were prepared and screw holes were machined. At this time, the number of defective manufacturing defects was investigated, and the manufacturing yield was calculated.

Further, an experiment for evaluating the consolidation force was performed on the screw holes of the metal plates each having the screw holes. In the experiment for evaluating the consolidation force of the screw hole, a screw fixing device capable of measuring the tightening torque was used, and the male screw was screwed into the screw hole of the metal plate. At this time, the relationship between the angle of the male screw and the consolidation torque was measured. The angle between the angle (°) of the obtained male screw and the consolidation torque (N.m) is differentiated by the corner, and the ratio of the angle of rotation of the male screw (°) to the consolidation torque (N.m/°) is obtained. Relationship.

Fig. 10 is a view showing the relationship between the rotation angle of the male screw and the tightening torque and the change ratio of the rotation angle of the male screw to the tightening torque in the experiment for evaluating the fixing force of the screw hole. As shown in the figure, when the rotation angle increases as the male screw is screwed in, the tightening torque is changed from a certain state in which the initial stage is almost zero to an increase, and then formed to be substantially constant and then decreased. From the relationship between the angle of rotation and the tightening torque, the point O at which the tightening torque is changed from a certain state of 0 to an increase is obtained.

On the other hand, the change ratio of the tightening torque is such that when the rotation angle increases as the male screw is screwed in, after the above-mentioned point O starts to increase, it is substantially constant, and then decreases. From the relationship between the angle of change of the angle of the male screw and the tightening torque, the change ratio of the tightening torque is changed from a certain state to a reduced corner. Let the point on the curve of the relationship between the display corner and the tightening torque of this corner be point A. This point A indicates the point at which the female thread (screw hole) begins to plastically deform.

A line L connecting the point O and the point A thus obtained is drawn. Again A straight line L' in which the straight line L is moved in parallel by 10° in the direction in which the corner is increased. Let the intersection of this straight line L' and the curve showing the relationship between the rotation angle and the tightening torque be point B. The ratio of the tightening torque (N.m) of the point B to the tightening torque TA (N.m) of the point A (TB/TA, dimensionless) was calculated as an index for evaluating the fixing force of the screw hole. This type of TB/TA shows the ratio of the tightening torque maintained after the female thread begins to plastically deform, in other words, the ratio of the screw hole to the reinforcing force of the male screw after the female thread begins to plastically deform. Therefore, the larger the TB/TA, the better the consolidation force of the screw holes and the male screws.

The meanings of the symbols in the "Evaluation of Consolidation Force" column in Tables 1-3 are as follows.

VG (Very Good): The display satisfies TB/TA≧1.2.

GD (Good): The display satisfies 1.2>TB/TA≧1.0.

FA (Fair): The display satisfies 1.0>TB/TA≧0.8.

BD (Bad): The display satisfies TB/TA<0.8.

Tables 1 to 3 show the experimental No. of each experiment, the thickness t of the metal plate, the processing method of the screw hole, the shoulder radius R of the pressure-bearing punch, R/t, and whether or not the above formula (1) is satisfied. ), the value of the radius r, r/t of the pre-drilled hole before forming the inner wall portion, whether it conforms to the above formula (2), the manufacturing yield, the value of the consolidation force index TB/TA and its evaluation, and the experimental classification . Here, whether or not the above formula (1) is Y is satisfied, the value of R/t is satisfied to satisfy the above formula (1), and when N is N, the value of R/t is not satisfied with the above formula (1). Further, whether or not the expression (2) is Y is satisfied, the value of r/t is satisfied to satisfy the above formula (2), and when N is N, the value of r/t is not satisfied with the above formula (2).

From Tables 1 to 3, the evaluation of the consolidation force is BD in the comparative example, whereas in the present invention, it is VG, GD or FA. Therefore, it has been confirmed that the metal plate with the screw hole of the present invention, the frame body having the metal plate with the screw hole, and the metal plate are manufactured by the screw hole and the male screw.

Further, in the comparative example (Experiment No. 1-1A, 2-1A, 3-1A), in the burr processing, the root portion of the vertical wall portion was broken due to the decrease in thickness, or the screw hole snail could not be completely formed by the thread cutting. The tooth is defective, and the number of occurrences increases as the thickness of the sample becomes thinner. As a result, in the comparative example, the manufacturing yield was all 70% or less. In contrast, in the example of the present invention, both are 90% In the above, the manufacturing yield is improved.

Further, in the comparative examples (Experiment No. 1-1B, 2-1B, and 3-1B), the following problem was observed, and the above problem was caused by the fact that the portion of the female thread corresponding to the inner wall portion was not equivalent. Since the peripheral portion of the outer wall portion is supported, the rigidity is low, and therefore, the machining accuracy of the female thread which is difficult to perform the correct tapping screw and cannot maintain the machining accuracy is not uniform in the circumferential direction. Thus, when the rigidity of the female threaded portion corresponding to the inner wall portion is weak and the machining accuracy of the female thread is low, the structural state between the female thread and the male screw is not uniform in the circumferential direction of the female thread.

Further, in the example of the present invention, in the test in which the value of R/t was less than 0.5 and the value of R/t exceeded 1.0, it was confirmed that the manufacturing yield was slightly lowered. On the other hand, in the experiment in which the value of r/t was less than 0.5, it was confirmed that the manufacturing yield was slightly lowered. Further, in the experiment in which the value of r/t was 1.2 or less, the evaluation of the consolidation force was VG or GD. On the other hand, in the experiment in which the value of r/t exceeded 1.2, the evaluation of the consolidation force was FA. It is apparent from the above that in the outer wall portion forming step, the punch satisfying the above formula (1) is used, and the radius r of the pre-drilled hole before the pre-drilling is drilled into the inner wall portion satisfies the above formula (2), Thereby, the manufacturing yield and the fixing force of the screw holes can be further improved.

Industrial availability

The manufacturing method of the metal plate with the screw hole, the frame body having the metal plate with the screw hole, and the metal plate with the screw hole according to the present invention, the fixing force of the screw hole and the male screw even when the thin plate is formed Excellent and prevents damage to the screw holes. Therefore, the metal plate with the screw hole of the present invention, the frame body having the metal plate with the screw hole, and the metal with the screw hole When the manufacturing method of the board is applied to the frame of the outdoor unit or the substation of the air conditioner, it can contribute to the thinning of the metal sheet.

Claims (10)

A metal plate with a screw hole is a metal plate having a screw hole, the screw hole having a cylindrical outer wall portion rising from one side of the metal plate, and folding from the edge of the outer wall portion to the outer wall a cylindrical inner wall portion on the inner side of the inner portion; wherein the inner peripheral surface of the inner wall portion is formed with a female thread, and the front end of the inner wall portion is flush with the other surface of the metal plate, and the male screw is not screwed to In a state in which the female screw of the screw hole is formed, the outer circumferential surface of the inner wall portion is spaced apart from the inner circumferential surface of the outer wall portion, and the inner wall is screwed to the female screw of the screw hole. At least a portion of the outer peripheral surface of the portion abuts against the inner circumferential surface of the outer wall portion. A frame comprising: a metal plate having a screw hole; a member having a through hole; and a male screw that is screwed into the screw hole in a state of being inserted into the through hole to join the metal plate and the member having the through hole; The board is a metal plate with a screw hole as claimed in claim 1. A method of manufacturing a metal plate with a screw hole, the method of manufacturing a metal plate with a screw hole as claimed in claim 1, comprising the steps of: forming the outer wall portion on the metal plate and connecting to the inner side of the outer wall portion a circular plate portion; a pre-drilled hole is drilled in a center of the aforementioned circular plate portion; The inner disk portion is formed by bending the disk portion into which the pre-drilled hole is drilled to the inner side of the outer wall portion, and the female screw thread is formed on the inner circumferential surface of the inner wall portion that is formed. A method of manufacturing a metal plate with a screw hole according to claim 3, wherein in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness dimension t (mm), the use has the following formula (1) The punch of the shoulder size of the radius R (mm): 0.5 ≦ R / t ≦ 1.0 Equation (1). A method of manufacturing a metal plate with a screw hole as claimed in claim 3, wherein in the step of drilling the aforementioned pre-drilled hole in the metal plate having a thickness dimension t (mm), the pre-drilled hole is drilled into the aforementioned pre-drilled hole The radius r (mm) satisfies the following formula (2): 0.5 ≦ r / t ≦ 1.2 Equation (2). A method of manufacturing a metal plate with a screw hole according to claim 3, wherein in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness dimension t (mm), the use has the following formula (1) The punch of the shoulder size of the radius R (mm) is in the step of drilling the aforementioned pre-drilled hole of the metal plate, and drilling the pre-drilled hole into the radius r (mm) of the pre-drilled hole to satisfy the following formula (2): 0.5 ≦ R / t ≦ 1.0 Equation (1) 0.5 ≦ r / t ≦ 1.2 Equation (2). A manufacturing method of a metal plate with a screw hole, which is manufactured as a request item a method of attaching a metal plate of a screw hole, comprising: a hole opening step of drilling a pre-drilled hole in the metal plate; forming an outer wall portion and a circular plate portion, forming the outer wall portion concentrically with the pre-drill hole, And a circular plate portion connected to the inner side of the outer wall portion; the inner wall portion forming step of bending the circular plate portion to the inner side of the outer wall portion to form the inner wall portion; and the processing step of the inner wall portion The inner peripheral surface is machined with the aforementioned female thread. A method of manufacturing a metal plate with a screw hole according to claim 7, wherein in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness dimension t (mm), the use has the following formula (1) The punch of the shoulder size of the radius R (mm): 0.5 ≦ R / t ≦ 1.0 Equation (1). A method of manufacturing a metal plate with a screw hole as claimed in claim 7, wherein in the step of drilling the aforementioned pre-drilled hole in the metal plate having a thickness dimension t (mm), the pre-drilled hole is drilled to form the aforementioned circular plate The radius r (mm) of the aforementioned pre-drilled hole after the step of the portion satisfies the following formula (2): 0.5 ≦ r / t ≦ 1.2 Equation (2). A method of manufacturing a metal plate with a screw hole according to claim 7, wherein in the step of forming the outer wall portion and the disk portion by the metal plate having a thickness dimension t (mm), the use has the following formula (1) a punch having a shoulder size of a radius R (mm) is a step of drilling the pre-drilled hole into the pre-drilled hole after the step of forming the aforementioned circular plate portion in the step of drilling the aforementioned pre-drilled hole The radius r (mm) satisfies the following formula (2): 0.5 ≦ R / t ≦ 1.0 Equation (1) 0.5 ≦ r / t ≦ 1.2 Equation (2).