JP6433301B2 - Bush and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylindrical bush having a seam formed on a side wall and a manufacturing method thereof.

  Conventionally, a bushing technique in which a seam is formed on a side wall in a cylindrical shape is known. For example, as described in Patent Document 1.

  Patent Document 1 discloses a wound bush formed by bending a rectangular flat blank material into a cylindrical shape and having a seam inclined with respect to a generatrix on the outer peripheral surface. The technique described in Patent Document 1 has an object of facilitating close contact of the abutting surfaces forming the seam by inclining the seam with respect to the generatrix on the outer peripheral surface.

In the wound bush configured as described above, the blank material is usually formed by punching a plate material by press working. At this time, the end surfaces of both end portions of the blank material to be the butting surfaces are perpendicular to the surface to be the inner peripheral surface and the outer peripheral surface of the wound bush. Therefore, when the butt of the end face is curved blank so that cylindrical, as shown in FIG. 9, the gap G increases generated between both end surfaces. For example, when this winding bushing is used for a sliding bearing of a transmission, oil leaks from the gap G in the axial direction of the winding bushing, so that deterioration of hydraulic controllability such as responsiveness at the time of pressure increase becomes a problem.

JP-A-60-201115

  The present invention has been made in view of the above situation, and a problem to be solved is to provide a wound bushing having a small gap between butting surfaces forming a seam and a method for manufacturing the wound bushing. .

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1, a seam is formed in the side wall in a cylindrical shape, the seam is formed by a pair of butting surfaces substantially parallel to each other , and each end surface of one end in one direction is one surface in the plate thickness direction. The plate-like plate material formed to spread outward from the other side to the other side, the one side becomes an inner peripheral surface, and the respective end surfaces of the both end portions are abutted with each other to form the pair of abutting surfaces. As shown in the figure, it is formed by being curved in a cylindrical shape, and at both ends of the plate-like plate material, an arc portion curved so as to form an arc shape having a center of curvature on the one surface side is formed, Each end face of the both ends of the flat plate material is formed in parallel with the direction toward the center of curvature .

  According to a second aspect of the present invention, each of the pair of butting surfaces is substantially parallel to the radial direction of the bush.

In Claim 3 , the plate | board thickness of the said flat plate-shaped board | plate material is 1.2 mm or less.

In Claim 4 , each end surface of the both ends of the flat plate material is non-linear when viewed from the thickness direction of the flat plate material, and meshes with each other when the end surfaces are brought into contact with each other. It is a shape.

In Claim 5 , the process which prepares a board | plate material, the 1st bending process which bends the said board | plate material in circular arc shape, and forms the 1st circular arc-shaped bending part in the said board | plate material, and said 1st circular arc-shaped bending part were formed. A first cutting step of obtaining a primary processed plate having the first arc-shaped bent portion at one end by cutting the plate material at the first arc-shaped bent portion, and the primary processed plate into the first arc-shaped bent portion. A second bending step in which a second arc-shaped bent portion is formed in the primary processed plate, and the primary processed plate in which the second arc-shaped bent portion is formed is converted into the second circle. A second cutting step of obtaining a secondary processed plate having the first arc-shaped bent portion and the second arc-shaped bent portion at both ends by cutting at the arc-shaped bent portion, and the secondary processed plate, The first arc so that the end faces of both end portions face each other A third bending step of bending portion and the second circle arc bent portion in the same direction bending cylinder, it is intended to include a.

In Claim 6 , in said 1st cutting process, said 1st circular arc-shaped bending part is punched toward the outer peripheral surface side from the internal peripheral surface side of the said 1st circular arc-shaped bending part, and the said primary work board is obtained. Is.

According to claim 7 , in the second cutting step, the second arc-shaped bent portion is punched from the inner peripheral surface side to the outer peripheral surface side of the second arc-shaped bent portion, whereby the secondary processed plate is To get.

In Claim 8 , the plate | board thickness of the said board | plate material is 1.2 mm or less.

In Claim 9 , a 1st cutting process cut | disconnects so that the end surface of the edge part which has said 1st circular arc-shaped bending part of said primary processed board may become non-linear shape seeing from the plate | board thickness direction of the said primary processed board And the second cutting step has the second arc-shaped bent portion of the secondary processing plate when the respective end surfaces of the both end portions of the secondary processing plate abut each other in the third bending step. The end surface of the portion is cut so as to have a shape that meshes with the end surface of the end portion having the first arc-shaped bent portion.

  As effects of the present invention, the following effects can be obtained.

  In Claim 1, the clearance gap between butt | matching surfaces can be made small.

  In Claim 2, the clearance gap between the butt | matching surfaces can be made smaller.

In Claim 3 , the clearance gap between butt | matching surfaces can be made smaller.

In the fourth aspect , the length of the seam can be increased.

According to the fifth aspect of the present invention, a bush having a small gap between the butted surfaces can be manufactured.

In Claim 6 , the burr | flash which generate | occur | produces at the time of a cutting | disconnection can fill up the clearance gap of the radial direction outer side.

According to the seventh aspect of the present invention, when the burr generated at the time of cutting becomes a finished product, the gap on the radially outer side can be filled.

According to the eighth aspect of the present invention, it is possible to manufacture a bush having a smaller gap between the butt surfaces.

According to the ninth aspect , a bush having a long seam can be manufactured.

The bush which concerns on 1st embodiment of this invention is shown, (a) Front view, (b) Bottom view. BRIEF DESCRIPTION OF THE DRAWINGS (a) Top view and (b) Front view which show the board | plate material of the bush which concerns on 1st embodiment of this invention. Schematic which shows the (a) 1st bending process and the (b) 1st cutting process in the manufacturing method of the bush which concerns on 1st embodiment of this invention. Schematic which shows the (a) 2nd bending process and the (b) 2nd cutting process in the manufacturing method of the bush which concerns on 1st embodiment of this invention. Schematic which shows the 2nd step of the (b) 3rd bending process in the (a) 3rd bending process in the manufacturing method of the bush which concerns on 1st embodiment of this invention. Schematic which shows the sizing process in the manufacturing method of the bush which concerns on 1st embodiment of this invention. The flowchart of the manufacturing method of the bush which concerns on 1st embodiment of this invention. (A) Plan view showing a bush material according to the second embodiment, (b) Plan view showing a bush material according to the third embodiment, (c) Plan view showing a bush material according to the fourth embodiment . The bottom view which shows the conventional winding bush.

  In the following, the directions indicated by arrow U, arrow D, arrow F, arrow B, arrow L and arrow R in the figure are defined as upward, downward, forward, backward, leftward and rightward, respectively. To explain.

  First, with reference to FIG.1 and FIG.2, the outline | summary of a structure of the bush 10 of 1st embodiment is demonstrated.

  A bush 10 shown in FIG. 1 is a sliding bearing that rotatably supports a rotating shaft on a sliding surface. The bush 10 is formed in a cylindrical shape extending in the vertical direction. The bush 10 has a slip surface on the inner peripheral surface. A joint 11 is formed in the bush 10.

  The joint 11 is a cut that penetrates the inner peripheral surface and the outer peripheral surface of the bush 10. The joint 11 is formed on the side wall of the bush 10 so as to extend linearly from the upper bottom surface to the lower bottom surface of the bush 10. The joint 11 is formed by the left and right butting surfaces 11a.

  The butting surface 11 a is a surface that forms the seam 11. The left and right butting surfaces 11a are formed to face each other. The left and right butting surfaces 11a are formed substantially parallel to each other. The left and right butting surfaces 11a are in close contact with each other over substantially the entire surface so that the gap between the left and right butting surfaces 11a is small. The left and right butting surfaces 11 a are formed substantially parallel to the radial direction of the bush 10.

  The bush 10 configured as described above is formed by bending a flat plate 20 into a cylindrical shape. The plate member 20 shown in FIG. 2 is a material before the bush 10 is bent into a cylindrical shape. The plate material 20 is formed in a rectangular plate shape. An appropriate material (for example, an iron-based material) is used as the plate member 20. The plate thickness t of the plate material 20 is 1.2 mm or less. An arc portion 21 is formed on the plate member 20.

  The arc portion 21 is a portion that is curved so as to have an arc shape having a center of curvature c on the upper surface side of the plate material 20 (above the upper surface of the plate material 20). The arc portions 21 are formed at both ends of the plate member 20 in the left-right direction. The arc portion 21 is formed such that the radius of curvature r2 of the arc portion 21 is substantially the same as the radius r1 of the bush 10 (see FIG. 1). An end surface 21 a in the left-right direction of the arc portion 21 is formed so as to spread outward in the left-right direction as it goes from the upper surface to the lower surface of the plate member 20. The end surface 21 a is formed in parallel with the direction toward the center of curvature c of the arc portion 21.

  The bush 10 is formed by curving the plate member 20 configured in this manner into a cylindrical shape with a radius r1 so that the left and right end faces 21a face each other. That is, the left and right end surfaces 21a become the butting surfaces 11a, respectively. At this time, the plate member 20 is bent so that the upper surface of the plate member 20 becomes the inner peripheral surface (so that the arc portion 21 is bent upward in FIG. 2B).

As described above, a relatively thin plate thickness t = 1.2 mm or less is used as the plate material 20. When the plate thickness t exceeds 1.2 mm, when the plate member 20 is bent into a cylindrical shape, the area of the portion where the left and right end surfaces 21a (butting surfaces 11a) face each other increases. Along with this, the gap between the left and right end faces 21a also increases.
On the other hand, in the first embodiment, since the plate member 20 has a plate thickness t = 1.2 mm or less, the area of the portion where the left and right end faces 21a face each other is relatively small. Therefore, the gap between the left and right end faces 21a can be further reduced.

  In addition, as described above, the radius of curvature r2 of the arc portion 21 is formed to be substantially the same as the radius r1 of the bush 10. Furthermore, the end face 21a in the left-right direction of the arc portion 21 is formed in parallel to the direction toward the center of curvature c of the arc portion 21 (outwardly expanding toward the lower side). Therefore, when the plate member 20 is bent in a cylindrical shape as described above, the upper ends of the left and right end surfaces 21a come into contact with each other, and substantially the entire left and right end surfaces 21a come into contact with each other. Therefore, the gap between the left and right end faces 21a can be made very small.

The bush 10 configured in this way is used for, for example, a sliding bearing of a transmission. The conventional bush shown in FIG. 9 has a large gap G between the butted surfaces, so that oil easily leaks from the gap G. On the other hand, the bush 10 of the first embodiment can prevent oil leakage because the gap between the butted surfaces 11a is very small. Therefore, for example, responsiveness during hydraulic control can be improved.

  Next, a method for manufacturing the bush 10 will be described with reference to FIGS.

  First, the plate material M is supplied to a molding machine. The plate material M is transported forward by the transport belt and supplied into the molding machine. The plate M has a plate thickness of 1.2 mm or less.

  The plate M supplied to the molding machine is subjected to the first bending process shown in FIG. 3A (step S101). When the plate material M is conveyed forward and supplied to the molding machine, the plate material M is bent upward (in the direction of arrow a shown in FIG. 3) so that the bent portion has an arc shape. As a result, a first arc-shaped bent portion 211 is formed in the plate material M.

  Next, the plate material M on which the first arc-shaped bent portion 211 is formed is subjected to a first cutting step shown in FIG. 3B (step S102). After the first arc-shaped bent portion 211 is formed, the plate material M is cut from the upper rear to the lower front (in the direction of arrow b shown in FIG. 3) in the first arc-shaped bent portion 211. At this time, the plate material M is cut in parallel with the radial direction (direction toward the center of curvature) of the first arc-shaped bent portion 211. The remaining cut portion is used in a subsequent process as the primary processed plate 20a having the first arc-shaped bent portion 211 at the front end.

  After cutting in the first cutting process, the primary processed plate 20a is subjected to a second bending process shown in FIG. 4A (step S103). When the primary processed plate 20a is conveyed forward, the primary processed plate 20a is bent upward (in the direction of arrow c shown in FIG. 4A) so that the bent portion has an arc shape. Thereby, the 2nd circular arc-shaped bending part 212 is formed in the primary processed board 20a.

  Next, the primary processed plate 20a on which the first arc-shaped bent portion 211 and the second arc-shaped bent portion 212 are formed is subjected to a second cutting step shown in FIG. 4B (step S104). After the second arc-shaped bent portion 212 is formed, the primary processed plate 20a is cut at the second arc-shaped bent portion 212 from the upper rear to the lower front (in the direction of arrow b shown in FIG. 4). At this time, the plate material M is cut in parallel with the radial direction (direction toward the center of curvature) of the second arc-shaped bent portion 212. This cut piece has a first arc-shaped bent portion 211 at the upper end and a secondary processed plate (that is, the plate material 20 (see FIG. 2)) having the second arc-shaped bent portion 212 at the lower end. Used in.

  Next, the plate member 20 is subjected to a third bending step shown in FIG. 5 (step S105 and step S106). The third bending step is divided into a U-bending step shown in FIG. 5A and a rough bending step shown in FIG.

  In the U-bending step (step S105) shown in FIG. 5A, the upper and lower ends of the plate member 20 are pressed backward, so that the upper and lower ends of the plate member 20 are directed toward the center in the vertical direction of the plate member 20, respectively. It is bent (in the direction of arrow d shown in FIG. 5A). As a result, as shown in FIG. 5A, the plate member 20 is bent into a substantially U shape with the rear opening.

  Next, the substantially U-shaped plate member 20 is subjected to a rough bending process shown in FIG. 5B (step S106). When the first arc-shaped bent portion 211 and the second arc-shaped bent portion 212 are pressed forward, the plate material 20 bent in a substantially U shape moves forward (in the direction of arrow e shown in FIG. 5B). Bend. As a result, the substantially U-shaped plate member 20 has a cylindrical shape in which the end surface 211a of the first arc-shaped bent portion 211 and the end surface 212a of the second arc-shaped bent portion 212 abut each other, as shown in FIG. .

  Next, the plate member 20 bent into a cylindrical shape is subjected to a sizing process shown in FIG. 6 (step S107). In the sizing process, a die 30 is used. The die 30 is formed in a cylindrical shape, and the cross section of the inner periphery thereof is processed into a highly accurate perfect circle. In this sizing step, the plate material 20 bent into a cylindrical shape is moved in the left direction (the direction of the arrow f shown in FIG. 6) to pass through the inside of the die 30. Thereby, the cylindrical bush 10 with improved roundness of the outer peripheral surface is obtained.

  If necessary, the inner peripheral surface of the bush 10 is also sized to obtain a bush 10 having a desired inner diameter.

  In this manufacturing method, before the plate material M is cut to create the plate material 20, the plate material M is bent into an arc shape to form a first arc-shaped bent portion 211 and a second arc-shaped bent portion 212, and this first circle The arc-shaped bent portion 211 and the second arc-shaped bent portion 212 are cut. That is, since the plate material M is cut in the same state as the state bent into the cylindrical shape, the end surfaces 211a and 212a face each other in parallel when the plate material 20 is bent into the cylindrical shape. Therefore, when the end faces 211a and 212a are brought into contact with each other, the gaps can be brought into close contact with each other.

  Moreover, in the 1st cutting process and 2nd cutting process which are shown in FIG.3 (b) and FIG.4 (b), the outer peripheral surface side from the inner peripheral surface side of the 1st circular arc-shaped bending part 211 and the 2nd circular arc-shaped bending part 212 is shown. The plate material M (primary processed plate 20a) is cut. At this time, in the cut portion of the plate material M, the outer peripheral surface side is the burr side, and the inner peripheral surface side is the sagging side. However, in the subsequent third bending step (rough bending step), the plate member 20 is pressed from the outer peripheral surface side so as to be cylindrical, and at that time, the burr on the outer peripheral surface may fill the gap between the butted surfaces 11a. it can.

As described above, the bush 10 according to the first embodiment has a cylindrical shape, the seam 11 is formed on the side wall, and the seam 11 is formed by the pair of butting surfaces 11a substantially parallel to each other.
By comprising in this way, the clearance gap between the butt | matching surfaces 11a can be made small.

The bush 10 has the pair of butting surfaces 11a substantially parallel to the radial direction of the bush 10, respectively.
By comprising in this way, the clearance gap between the butt | matching surfaces 11a can be made smaller.

The bush 10 has a flat plate-like plate material 20 in which each end face 21a at both ends in one direction extends outwardly from one face in the thickness direction toward the other face, and the one face is an inner peripheral face. In addition, the end surfaces 21a of the both end portions are abutted with each other to form the pair of abutting surfaces 11a.
By comprising in this way, the clearance gap between the butt | matching surfaces 11a can be made smaller.

In addition, the bush 10 is formed with an arc portion 21 that is curved so as to have an arc shape having a center of curvature c on the one surface side at both ends of the flat plate material 20, and the flat plate material 20. The respective end surfaces 21a of the both end portions are formed in parallel with the direction toward the center of curvature c.
By comprising in this way, the clearance gap between the butt | matching surfaces 11a can be made smaller.

The bush 10 has a plate thickness t of the flat plate member 20 of 1.2 mm or less.
By comprising in this way, the clearance gap between the butt | matching surfaces 11a can be made smaller.

Moreover, the manufacturing method of the bush 10 which concerns on 1st embodiment is a 1st bending process which forms the 1st circular arc-shaped bending part 211 in the process of preparing the board | plate material M, and bending the said board | plate material M in the circular arc shape. Then, by cutting the plate material M on which the first arc-shaped bent portion 211 is formed at the first arc-shaped bent portion 211, a primary processed plate 20a having the first arc-shaped bent portion 211 at one end is obtained. A first cutting step and a second bending step of bending the primary processed plate 20a in an arc shape in the same direction as the first arc-shaped bent portion 211 to form a second arc-shaped bent portion 212 on the primary processed plate 20a. And cutting the primary processed plate 20a on which the second arc-shaped bent portion 212 is formed at the second arc-shaped bent portion 212, the first arc-shaped bent portion 211 and the second Arc-shaped bent portion 21 A second cutting step of obtaining a plate material 20 (secondary processed plate) having the above-mentioned shape, and the first circular arc-shaped bent portion 211 and the second plate plate 20 so that the end surfaces 211a and 212a of the both end portions face each other. And a third bending step that is bent in the same direction as the two arc-shaped bending portion 212 to form a cylindrical shape.
By comprising in this way, a bush with a small clearance between the butting surfaces 11a (the end surface 211a and the end surface 212a) can be manufactured.

Further, in the method for manufacturing the bush 10 according to the first embodiment, in the first cutting step, the first arc-shaped bent portion 211 is directed from the inner peripheral surface side to the outer peripheral surface side of the first arc-shaped bent portion 211. By punching out, the primary processed plate 20a is obtained.
By configuring in this way, it is possible to fill the gap on the radially outer side when the burr generated during cutting becomes a finished product.

Further, in the method for manufacturing the bush 10 according to the first embodiment, in the second cutting step, the second arc-shaped bent portion 212 is directed from the inner peripheral surface side to the outer peripheral surface side of the second arc-shaped bent portion 212. By punching out, the plate material 20 is obtained.
By configuring in this way, it is possible to fill the gap on the radially outer side when the burr generated during cutting becomes a finished product.

The plate thickness M of the plate material M is 1.2 mm or less.
By comprising in this way, the bush 10 with a smaller clearance between the butting surfaces 11a (the end surface 211a and the end surface 212a) can be manufactured.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described configuration, and various modifications can be made within the scope of the invention described in the claims.

  For example, in the first embodiment, the seam 11 is formed so as to extend linearly from the upper bottom surface to the lower bottom surface of the bush 10, but is not limited thereto. For example, the respective end surfaces 21a at both ends in the left-right direction of the plate material 20 are non-linear when viewed from the plate thickness direction of the plate material 20, and can also have a shape that meshes with each other when the end surfaces 21a are brought into contact with each other. It is.

As an example of the above, for example, as in the second embodiment shown in FIG. 8A, the left end surface 21a of the plate member 20 has a concave shape recessed in the right direction, and the right end surface 21a corresponds to the left end surface 21a. It can also be configured to have a convex shape that is convex in the right direction.
Further, as in the third embodiment shown in FIG. 8B, the left and right end surfaces 21a of the plate member 20 can be configured to have a zigzag shape in which unevenness is repeated left and right.
Further, as in the fourth embodiment shown in FIG. 8C, the left end surface 21a of the plate member 20 has an arc shape that is recessed in the right direction, and the right end surface 21a is convex in the right direction corresponding to the left end surface 21a. It is also possible to configure so as to have an arc shape.
By comprising in this way, the length from the front end of the said end surface 21a along the end surface 21a of the board | plate material 20 to a rear end becomes long in planar view. Therefore, when the plate member 20 configured in this manner is curved in a cylindrical shape, the length of the joint 11 (the length in the front-rear direction of the abutting surface 11a along the left and right abutting surfaces 11a) becomes longer. For this reason, even if oil enters through a slight gap between the butting surfaces 11a when the bush 10 is used, it is not easy for the oil to pass through the gap from one bottom surface of the bush 10 to the other bottom surface. As a result, oil leakage can be made more difficult to occur.

As described above, in the bush 10 according to the second embodiment, the third embodiment, and the fourth embodiment, the end surfaces 21a of the both ends of the flat plate material 20 are in the thickness direction of the flat plate material 20. When viewed from above, the shape is non-linear and meshes with each other when the end surfaces 21a are brought into contact with each other.
By comprising in this way, the length of the joint line 11 (distance of the part which the right and left abutting surfaces 11a (end surface 21a) mutually opposes) can be lengthened.

In the first cutting step, cutting is performed so that the end surface of the end portion having the first arc-shaped bent portion 211 of the primary processed plate 20a is non-linear when viewed from the thickness direction of the primary processed plate 20a. The second cutting step includes an end portion having the second arc-shaped bent portion 212 of the plate member 20 when the end surfaces 211a and 212a of the both end portions of the plate member 20 are brought into contact with each other in the third bending step. The end surface 212a is cut so as to have a shape that meshes with the end surface 211a of the end portion having the first arc-shaped bent portion 211.
By configuring in this way, it is possible to manufacture the bushing 10 having a long joint 11 (the distance between the portions where the left and right butting surfaces 11a (end surfaces 211a and 212a) face each other).

  In the first embodiment, the bush 10 is formed by bending the flat plate material 20 into a cylindrical shape, but is not limited to this, and can be formed by various methods. .

  In the first embodiment, the left and right butting surfaces 11a of the bush 10 are in close contact with each other so that the gap between the left and right butting surfaces 11a is small. There is no need to adhere closely to. The bush 10 includes one having a slight gap between the left and right butting surfaces 11a.

  In the first embodiment, the left and right butting surfaces 11a of the bush 10 are formed substantially parallel to the radial direction of the bush 10. However, the present invention is not limited to this. For example, the left and right butting surfaces 11 a may be formed obliquely with respect to the radial direction of the bush 10.

  Moreover, in 1st embodiment, although the end surface 21a of the board | plate material 20 shall be formed in parallel with the direction which goes to the curvature center c of the circular arc part 21, it is not limited to this. For example, the end surface 21 a may be formed obliquely with respect to the direction toward the center of curvature c of the arc portion 21.

  Moreover, in 1st embodiment, although plate | board thickness t of the board | plate material 20 was 1.2 mm or less, it is not limited to this, The thing exceeding 1.2 mm can also be used.

10 Bush 11 Seam 11a Butt Face 20 Plate Material (Secondary Processed Plate)
20a Primary processed plate 21 Arc portion 21a End surface 211 First arc-shaped bent portion 211a End surface 212 Second arc-shaped bent portion 212a End surface

Claims (9)

A seam is formed on the side wall in a cylindrical shape, and the seam is formed by a pair of butting surfaces substantially parallel to each other ,
A plate-like plate material formed so that each end face of both end portions in one direction extends outwardly from one surface in the plate thickness direction to the other surface, so that the one surface becomes an inner peripheral surface, and Formed by curving into a cylindrical shape so that the respective end faces of both ends are abutted against each other to form the pair of abutting faces,
A curved arc portion is formed at both ends of the flat plate material so as to form an arc shape having a center of curvature on the one surface side,
Each end surface of the both end portions of the flat plate material is formed in parallel with a direction toward the center of curvature.
Bush. Each of the pair of butting surfaces is substantially parallel to the radial direction of the bush,
The bush according to claim 1. The plate thickness of the flat plate material is 1.2 mm or less,
The bush according to claim 1 or claim 2. Each end face of the both ends of the flat plate material is non-linear when viewed from the plate thickness direction of the flat plate material, and has a shape that meshes with each other when the end surfaces are brought into contact with each other.
The bush according to any one of claims 1 to 3 .   Preparing the plate material;
  A first bending step of bending the plate material in an arc shape to form a first arc-shaped bent portion in the plate material;
  A first cutting step of obtaining a primary processed plate having the first arc-shaped bent portion at one end by cutting the plate material on which the first arc-shaped bent portion is formed at the first arc-shaped bent portion;
  A second bending step of bending the primary processed plate in an arc shape in the same direction as the first arc-shaped bent portion, and forming a second arc-shaped bent portion in the primary processed plate;
  By cutting the primary processed plate on which the second arc-shaped bent portion is formed at the second arc-shaped bent portion, the first arc-shaped bent portion and the second arc-shaped bent portion are respectively provided at both ends. A second cutting step for obtaining a secondary processed plate;
  A third bending step of bending the secondary processed plate into a cylindrical shape by bending in the same direction as the first arc-shaped bent portion and the second arc-shaped bent portion so that the end faces of the both end portions face each other; ,
  A method for manufacturing a bush comprising:   In the first cutting step, the first processed plate is obtained by punching the first arc-shaped bent portion from the inner peripheral surface side to the outer peripheral surface side of the first arc-shaped bent portion.
  The method for manufacturing a bush according to claim 5. In the second cutting step, the secondary processed plate is obtained by punching the second arc-shaped bent portion from the inner peripheral surface side to the outer peripheral surface side of the second arc-shaped bent portion.
A method for manufacturing the bush according to claim 5 or 6 . The plate thickness of the plate material is 1.2 mm or less,
The method for manufacturing a bush according to any one of claims 5 to 7 . In the first cutting step, the end surface of the end portion having the first arc-shaped bent portion of the primary processed plate is cut so as to be non-linear when viewed from the thickness direction of the primary processed plate,
In the second cutting step, when the respective end surfaces of the both end portions of the secondary processed plate are brought into contact with each other in the third bending step, the end portion having the second arc-shaped bent portion of the secondary processed plate Cutting so that the end surface has a shape that meshes with the end surface of the end portion having the first arc-shaped bent portion,
The manufacturing method of a bush as described in any one of Claim 5-8.

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