JP2011031286A - Method of manufacturing nearly cylindrical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a nearly cylindrical member on the bottom surface of a cup-shaped member of which a large opening is formed and, furthermore, which is also high in dimensional accuracy. <P>SOLUTION: The method of manufacturing a nearly clutch part 1 in which a large opening 2a is formed on the bottom surface of a cup-shaped member comprises: a first stage where a coil material 10 is formed into a desired size by performing trimming and also a blank material 13 is obtained by forming an opening 12 for working by piercing; a second stage where the blank material is formed into the cup-shaped member by performing drawing in the peripheral part of the blank material at the drawing rate of 70-90% several times; a third stage where ironing is applied to the side wall 3 of the cup-shaped member; and a fourth stage where the opening 2a is formed in the bottom part 2 of the cup-shaped member by piercing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a substantially cylindrical member. More specifically, the present invention relates to a method of manufacturing a substantially cylindrical member in which a large opening is formed on the bottom surface of a cup-shaped member by pressing.

  A cup-shaped member having a large opening at the bottom is difficult to mold with a constant plate thickness with high dimensional accuracy, and it is more difficult to form a notch on the side surface. This is because the stress associated with processing remains in the product as residual stress in each process, so the dimensional accuracy cannot be made constant, and it is difficult to make the thickness constant due to material thickness variation and material anisotropy. . The following three methods can be considered as a method of forming such a substantially cylindrical member.

In the first method, a plate material is drawn into a cup shape with a drawing die to form an intermediate material, and then a hole is formed on the bottom surface of the cup shape, and the side wall is cut by cutting or the like.
The second method is drawing using a blank material in which a product shape is developed, and then performing cutting, piercing, or the like.
The third method is a method in which a pipe-shaped member and a five-circle coin-shaped member, that is, a member having an opening at the center are joined by welding.

  In addition, Patent Document 1 describes that a circular flat plate material is formed into a cup-shaped member by pressing at a low drawing ratio. Patent Document 2 describes one using flow forming. In addition, Patent Document 3 describes a method for squeezing an opening of a pipe-shaped material.

JP 2006-68781 A JP-A-10-331868 JP 2001-121229 A

  According to the 1st method, when forming in cup shape, the plate | board thickness of the round part which a bottom part and a side wall are continuing tends to reduce, and variation arises in plate | board thickness. In addition, if an opening is formed in the bottom and a notch is formed in the side wall due to the influence of residual stress during processing, a springback occurs and the product is easily deformed. In particular, the processing of the side surface is complicated and takes time.

  According to the second conventional method, since the development blank is drawn, it is difficult to make the plate thickness constant. Moreover, when this also forms an opening part in a bottom part or a side wall, a springback will arise and a product will deform | transform easily.

  According to the third conventional method, labor is required and the manufacturing cost increases. Furthermore, the product is easily deformed by heat during welding, and a post-process for correcting the deformation is required.

  When a plate material is formed by pressing, it is difficult to make the product thickness uniform and to stabilize the product shape accuracy. Therefore, the present invention is a substantially cylindrical member having a large opening on the bottom surface of the cup-shaped member, a shape having a notch on the side surface, and high uniformity in overall thickness and dimensional accuracy of the shape. It is an object to provide a manufacturing method.

A method for manufacturing a substantially cylindrical member according to the present invention (Claim 1) is a method for manufacturing a substantially cylindrical member in which a large opening is formed on the bottom surface of a cup-shaped member, and is substantially circular by trimming a plate material. A first step of obtaining a blank material in which an opening for preliminary processing is formed by piercing at the center thereof, and a plurality of drawing moldings with a drawing ratio of 70 to 90% around the opening of the blank material A second step of forming a cup-shaped member consisting of a bottom portion and a side wall by performing the rotation, a third step of applying a squeaking process to the side wall of the cup-shaped member, and piercing the bottom portion of the cup-shaped member And a fourth step of forming the opening.
The squeezing ratio is a percentage of the product diameter with respect to the blank diameter.

  Such a pressing device preferably includes a step of forming an opening on the side wall by trimming or piercing after the fourth step.

  Further, it is preferable to include a sixth step of correcting the spring back of the side wall after the fifth step.

  Further, it is preferable that a process of pressing the bottom portion is performed between the second step and the third step or in the third step.

In the method for manufacturing a substantially cylindrical member according to the present invention (Claim 1), since an opening for preliminary processing is formed in a blank material and then drawn, the stress (residual stress) remaining in the product can be reduced, and the bottom portion Even if an opening is formed in the side wall, it is difficult to deform.
Moreover, since the cup-shaped member is formed by performing drawing with a drawing ratio of 70 to 90% a plurality of times, a reduction in the thickness of the portion where the bottom and the side wall are continuous (the rounded portion) is prevented. The strength of the part can be increased.
Furthermore, after forming a large opening at the bottom, the side wall is subjected to plastic deformation by squeeze processing, so that deformation of the large opening can be prevented.

  Since the cylindrical member obtained by such a manufacturing method is uniform with high dimensional accuracy, the thickness of the entire member can be prevented from lowering the strength of the member due to partial reduction in thickness. it can. In particular, the member manufactured by this manufacturing method is used in a situation where stress is likely to concentrate in a weak place by receiving centrifugal force due to rotational motion and inertial force due to motion in various other directions, for example, Suitable for clutch case. Note that a pressure is applied to the clutch case in a direction from the tip of the side wall toward the rounded portion. Since the cylindrical part obtained by this manufacturing method has the strength of a rounded part, it can receive the said load reliably.

  In such a method for manufacturing a substantially cylindrical member, when the fourth step is followed by a step of forming an opening in the side wall by trimming or piercing (Claim 2), the dimensions of the opening The accuracy can be increased. That is, normally, when the opening is formed in the side wall, the side wall is not continuous in the circumferential direction, so that spring back is caused by the residual stress generated in the side wall and the direction of deformation of the side wall becomes non-uniform. However, according to the present manufacturing method, the side wall is squeezed so that the direction of the spring back can be aligned inward in the radial direction.

  Further, when the sixth step of correcting the spring back of the side wall is provided after the fifth step (Claim 3), the dimensional accuracy of the entire shape including the opening can be further increased. That is, since the side wall is squeezed, the direction of the spring back of the side wall is aligned inward in the radial direction, and the dimensional accuracy can be easily increased in a single step of expanding the side wall outward.

  In the case where a process of pressing the bottom portion between the second step and the third step or in the third step is performed (Claim 4), the dimensional accuracy can be easily increased without increasing the number of additional steps. .

FIG. 1a is a front view of a substantially cylindrical member manufactured by the manufacturing method of the present invention, and FIG. 1b is a cross-sectional view taken along the line II of FIG. 1a. FIG. 2a is a schematic view showing a step of obtaining a blank material in the method for producing a substantially cylindrical member of the present invention, and FIG. 2b is a side view of the blank material shown in FIG. 2a. FIG. 3a is a schematic view showing a process of obtaining an intermediate material from a blank material, and FIG. 3b is a side view of each process of a member processed by the process of FIG. 3a. FIG. 4a is a schematic view showing a process of obtaining the substantially cylindrical member of the present invention from an intermediate material, and FIG. 4b is a side view of each process of the member processed by the process of FIG. 4a.

  FIG. 1 shows a substantially cylindrical clutch component 1 manufactured by the manufacturing method of the present invention. The clutch component 1 is a cup-shaped member, and the vertical wall 3 has eight notches 3a and the bottom surface 2 has large holes 2a. This is a part that puts the clutch plate inside and rotates together with the clutch plate. Therefore, force is applied in the axial direction (longitudinal direction) in assembling the parts. Further, since a force (centrifugal force) is applied in the circumferential direction by the rotation, the parts are easily deformed by the force. Furthermore, since many notches are also formed, the possibility of further deformation is high. Therefore, high dimensional accuracy is required in the entire region of the shape and plate thickness of the parts so as not to partially reduce the strength (so as not to deform).

  In addition, as a field | area where the cylindrical member obtained by this invention is used, they are various cases and a rotary body. Below, the manufacturing method of such components is explained in full detail.

  First, the shape of each part of the substantially cylindrical clutch component 1 manufactured by the present invention will be described with reference to FIGS. 1a and 1b. A clutch component 1 shown in FIGS. 1 a and 1 b includes a ring-shaped bottom portion (bottom surface) 2 and side walls 3 (vertical walls) that rise continuously from the periphery of the bottom portion 2. The side wall 3 and the bottom 2 are continuous via a rounded portion 4 that is smoothly curved.

In FIG. 1, the cylindrical member has a diameter of about 208 mm and a side wall height of about 61 mm. The thickness of the side wall is about 3 mm. The radius of curvature of the outer surface of the rounded portion 4 is about 2 mm. The clutch part 1 has a diameter of 150 to 300 mm, preferably 205 to 215 mm, a side wall height of 20 to 100 mm, preferably 50 to 70 mm, and a plate thickness of 1 to 5 mm, preferably 2 -4 mm, and the radius of curvature of the rounded portion is about 1-3 mm. As the material, a steel plate having a tensile strength of 400 N / mm ² or more is preferable from the viewpoint of strength.

  The bottom surface 2 is formed with a circular hole (opening) 2a. The inner diameter of the opening 2a is about 197 mm, which is about 95% of the inner diameter of the cup. In addition, the shape of the opening 2a can be formed in an elliptical shape or a rectangular shape in addition to a circular shape. A plurality of small openings may be formed. Furthermore, according to the manufacturing method of the present invention to be described later, the diameter of the circular opening 2a is 70 to 98%, particularly 90 to 96% with respect to the inner diameter of the cup while maintaining a high dimensional accuracy of the shape and thickness. Sometimes the effect of the present invention is high.

  Eight rectangular openings 3a (notches) reaching the upper part of the side wall 3 are formed in the side wall 3 at equal intervals in the circumferential direction. The notch 3a has a height of about 51.7 mm and a width of about 45 mm. The notch 3a may be a hole whose upper end does not reach the outside. Further, as the shape of the cutout portion 3a, a circular shape, an elliptical shape, or a star shape can be used in addition to a polygonal shape such as a triangle, a rectangle, or a rhombus. Note that the cutout portion 3 a having such a shape may be a hole formed in the side wall 3 that does not reach the upper end of the side wall 3. The height of the notch 3a is 10 to 90 mm, preferably 40 to 60 mm, and the width is 10 to 80 mm, preferably 30 to 60 mm. In addition, the number of the notch parts 3a is 1-20, Preferably it is 5-15.

  Next, the manufacturing method of the clutch component 1 of FIG. 1 is demonstrated using FIG. First, as shown in FIG. 2a, a predetermined amount of a plate is cut out from a plate material wound in a coil shape, and a blank material for drawing is obtained. At this time, the coil material 10 is prepared first, and the coil material 10 is cut into an appropriate length (the cut coil material 10a). Then, simultaneously with the cutting, the upper and lower end edges in the width direction are trimmed to form arcs 11 and 11 that are part of a circular shape. Note that an arrow A in FIG. 2b indicates a direction in which trimming or piercing is performed.

  Next, a small-diameter preliminary processing opening 12 (hereinafter referred to as a preliminary processing opening) is formed at the center by piercing. The opening 12 is used for suppressing plate reduction in drawing and reducing load in squeeze processing. In addition, trim processing is performed so that the entire shape including the arcs 11 and 11 is circular. The trim processing is performed with two large arc-shaped trim molds that connect the left and right ends of the upper and lower arcs 11 and 11 respectively (step S1). This is the blank material 13. The preliminary processing opening 12 has a diameter of about 100 to 150 mm, preferably about 48 to 72% of the product circular shape (inner diameter dimension). In this way, when the coil material is cut and then trimmed into a circle, the yield can be improved compared to normal blanking in which a circular plate is removed from the coil material.

  Subsequent to the first step S, as shown in FIGS. 3a and 3b, the blank material 13 is drawn (step S2). The drawing is performed by drawing a plurality of drawing operations at a drawing ratio of about 70 to 90% around the small-diameter opening of the blank 13. The drawing ratio is preferably 75 to 85%. Step S2a in the drawing is the first drawing. Further, in step S2b, the intermediate drawing product 13a deformed by the molding in step S2a is further subjected to a second drawing at a drawing rate of 70 to 90%. By gradually narrowing down to a small diameter in this way, it is possible to prevent the thickness of the rounded portion 12 from being reduced, thereby making the final thickness of the entire part uniform. In step S2a, the radius of curvature of the rounded portion 4 is about 15 to 20 mm, and in step S2b is about 5 to 10 mm. In these drawing processes S2a and S2b, the rounded portion 4 is still large and the bottom portion 2 is inclined, and is not flat.

  The number of times of drawing and the drawing rate per time are the ease of drawing due to the material or the shape of the final part, such as the yield and labor by increasing the drawing process, and the conventional drawing technology. Decided in consideration. Note that the aperture ratio may be changed for each aperture. Here, the drawing ratio is expressed by the diameter after processing / the diameter before processing × 100 (%).

  Next, squeeze molding is performed on the side wall 3 that has been thickened by performing the drawing (step S2) (step S3). In this squeeze molding, the thickness of the side wall is reduced, and the strength is increased by plastic deformation. Note that this squeeze molding is performed in a compression field (push squeeze squeeze) so as not to greatly reduce the thickness of the side wall. Therefore, in the squeeze molding, the molding force is set to such a degree that the side wall 3 does not become defective due to buckling or the like. The molding force varies depending on the shape and material of the product.

  Before proceeding to the fourth step, the bottom surface of the blank material 13 is pressed to flatten the inclined bottom portion 2 and shape the rounded portion 4 to a predetermined size. Thus, the cup-shaped intermediate material 14 with little difference in plate thickness can be formed by performing the pretreatment and the first step S1 to the third step S3.

  As shown in FIGS. 4a and 4b, the bottom 2 of the intermediate material 14 is pierced to form an opening 2a (step S4). If the opening 2a is large, the opening is usually easily deformed due to the influence of anisotropy and the like due to the processing such as drawing. For example, it may be deformed into an elliptical shape. However, since the intermediate material 14 is plastically deformed on the side wall 3 and has an apparent yield point, the amount of springback can be suppressed. That is, since the side wall 3 is erected from the peripheral edge of the bottom part 2 of the intermediate material 14, it acts like a rib and is reinforced, and even if the opening part 2a is formed, the spring back is used to form the opening part 2a. The shape is difficult to deform. In addition, since the side wall 3 extends upward by drawing and the material flows radially outward so that the diameter of the opening 2a also increases at the bottom 2, the material is obtained by that amount, so the yield is improved. .

  Thereafter, the notch 3a is formed on the side wall 3 by trimming (step S5). Eight notches 3 a are formed at equal intervals in the circumferential direction of the side wall 3. In this embodiment, first, four notches 3a are formed at equal intervals (step S5a). Next, the notch portions 3a are respectively formed in the middle of the formed notch portions 3a so as to form a total of eight notch portions 3a (step S5b). If the cutout is small, the entire trimming process can be performed at once.

  Further, since the tip of the notch 3a reaches the upper part, the side wall 3 does not continue in the circumferential direction. When such a notch is formed in the tubular member, the side wall 3 causes spring back due to residual stress or the like generated inside the side wall 3 during processing, and the eight divided side walls 3 become complicated. It will be deformed. However, according to this manufacturing method, since the side wall 3 is squeezed in the step S4, the direction of the spring back is aligned inward in the radial direction. Therefore, it becomes easy to perform the process which corrects a spring back after that.

  Subsequent to the step S5, the upper end face is cut to align the entire length (height) of the side wall 3 (step S6a). Thereafter, the spring back generated by the processing in the steps S5 and S6a is corrected (step S6b). By applying force from the inner diameter to the outer diameter side of the side wall 3 that has been spring-backed inward (taper punch, cam, etc.), it is only necessary to correct it in the same direction, that is, outward in the radial direction. be able to.

  Thus, since the clutch component 1 obtained by the manufacturing method of the present application is uniform with high dimensional accuracy, the thickness of the entire member can be prevented from partially decreasing due to the thickness being partially reduced. it can. In particular, the members manufactured by the manufacturing method of the present application are suitable for use in situations where stress is likely to be concentrated in weak locations by receiving centrifugal force due to rotational motion and inertial force due to motion in various other directions. ing.

1 Tubular member 2 Bottom (bottom)
2a Opening (hole)
3 Side wall (vertical wall)
3a Notch (opening)
4 Round part 10 Coil material 10a Plate material (Cut coil material)
11 Arc 12 Opening 13 for processing Blank material 13a Intermediate molded product 14 Intermediate material

Claims (4)

A manufacturing method of a substantially cylindrical member in which a large opening is formed on the bottom surface of a cup-shaped member,
A first step of trimming a plate material to form a substantially circular shape, and forming a blank material by forming an opening for preliminary processing by piercing at the center thereof; and
A second step of forming a cup-shaped member composed of a bottom and a side wall by performing drawing at a drawing rate of 70 to 90% around the opening of the blank material a plurality of times;
A third step of squeezing the side wall of the cup-shaped member;
A method of manufacturing a substantially cylindrical member comprising a fourth step of forming an opening by piercing at the bottom of the cup-shaped member.   The manufacturing method of the substantially cylindrical member of Claim 1 provided with the 5th process of forming an opening part in the said side wall by the trimming process or the piercing process after the said 4th process.   The manufacturing method of the substantially cylindrical member of Claim 2 provided with the 6th process of correcting the spring back of a side wall after the said 5th process.   The manufacturing method of the substantially cylindrical member in any one of Claim 1, 2 or 3 which performs the process which presses a bottom part between the said 2nd process and a 3rd process, or a 3rd process.

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