Patent Application
20250128309
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2023-181955, filed on Oct. 23, 2023, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a press die apparatus.
Japanese Laid-Open Patent Publication No. 2021-37528 discloses a pressing apparatus. This apparatus includes punches, a die with die holes into which the punches are respectively inserted and withdrawn, and a backing plate located directly beneath and adjacent to the die to support it. In the above publication, the backing plate is referred to as a die holder.
The backing plate has discharge holes that are respectively connected to the die holes. Punched members, which are punched out of the metal plate by the die and punches, are respectively discharged out of the discharge holes through the die holes.
When the punched members in the metal plate are located proximate to each other, the corresponding die holes are located proximate to each other. As a result, the discharge holes respectively connected to the die holes are also located proximate to each other. The closer the discharge holes are to each other, the narrower the width of a partition wall separating them. In this case, there is a risk that the strength of the backing plate, which is essential for supporting the die, and consequently the strength of a press die apparatus, may be reduced.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
A press die apparatus according to an aspect of the present disclosure includes a die including die holes into which punches are respectively inserted and withdrawn. The punches are configured to punch out a workpiece. The die also includes first partition walls, each separating adjacent ones of the die holes from each other. The press die apparatus also includes a backing plate that is adjacent to the die to support the die. The die includes die hole groups, each including the die holes that are adjacent to each other. The backing plate includes backing holes respectively connected to the die hole groups and a second partition wall, separating adjacent ones of the backing holes from each other. The second partition wall has a widened section that increases in width, continuously or in a stepwise manner, as the widened section extends away from the die. A maximum width of the widened section is greater than a width of the first partition wall.
Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.
This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted.
Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art.
In this specification, “at least one of A and B” should be understood to mean “only A, only B, or both A and B.”
A press die apparatus according to an embodiment will now be described with reference to
First, the rotor core 11 will be described.
As shown in
The rotor core 11 includes a central hole 12 and magnet accommodating holes 13, which respectively accommodate magnets (not shown). The rotor core 11 has, for example, twenty magnet accommodating holes 13. The central hole 12 and the magnet accommodating holes 13 extend through the rotor core 11 in the axial direction. The central hole 12 and the magnet accommodating holes 13 are formed by through-holes in the iron core pieces 11a, with the through-holes connected to each other.
The magnet accommodating holes 13 are arranged on the outer circumferential portion of the rotor core 11 at intervals in the circumferential direction. Each magnet accommodating hole 13 has a substantially rectangular shape with long sides and short sides in plan view. Two magnet accommodating holes 13 adjacent to each other in the circumferential direction are inclined in opposite directions with respect to the circumferential direction.
As shown in
The press die apparatus 20 includes a lower die assembly 21 and an upper die assembly 22 that is configured to move toward and away from the lower die assembly 21.
The lower die assembly 21 includes a die holder 30, a backing plate 40, a die plate 50, and a die 60. The die holder 30 is, for example, the lower part of the press die apparatus 20. The backing plate 40 is fixed to the upper surface of the die holder 30. The die plate 50 is fixed to the upper surfaces of the die holder 30 and the backing plate 40. The die 60 is fixed to the die plate 50.
As shown in
Punches 80, which will be described later, are respectively inserted into and withdrawn from the die holes 61. The die holes 61 respectively form the through-holes, which define the magnet accommodating holes 13, in the workpiece W by punching out the workpiece W using the punches 80.
Hereinafter, the circumferential direction of the die holes 61 arranged in an annular pattern will be referred to as a circumferential direction C, and the radial direction of the die holes 61 will be referred to as a radial direction R.
Each die hole 61 has a substantially rectangular shape with long sides and short sides in plan view. Two die holes 61 adjacent to each other in the circumferential direction C are inclined in opposite directions with respect to the circumferential direction C.
The die 60 includes die hole groups 61A, each including multiple die holes 61 that are adjacent to each other in the circumferential direction C. Each die hole group 61A includes, for example, four die holes 61. The die 60 includes, for example, five die hole groups 61A arranged in an annular pattern.
The widths of the die holes 61 and the widths of the first partition walls 62 are, for example, constant in the axial direction of the die holes 61. In this specification, the term “width” refers to the width in the circumferential direction C.
As shown in
The backing plate 40 is located directly beneath and adjacent to the die 60 to support the die 60. The backing plate 40 is located directly beneath and adjacent to the die plate 50 to support the die plate 50.
As illustrated in
As shown in
Each second partition wall 42 has a widened section 43 that continuously increases in width as it extends away from the die 60. The widened section 43 extends across the entire second partition wall 42. The width of the widened section 43 is smallest on the side where the die 60 is located and largest on the side opposite to where the die 60 is located. The maximum width of the widened section 43 is greater than the width of the first partition wall 62. The minimum width of the widened section 43 is smaller than the width of the first partition wall 62.
As shown in
The upper end of the widened section 43, which is the end of the widened section 43 where the die 60 is located, includes an edge 45 formed by continuously connecting the inclined surfaces 44 of adjacent ones of the backing holes 41 to each other. The angle formed between the two inclined surfaces 44, which define the edge 45, is, for example, 45° to 60°.
As shown in
As shown in
As shown in
As shown in
The die holder 30 includes a retaining recess 33 on the upper surface of the die holder 30. The retaining recess 33 opens toward the die 60 and retains the backing plate 40. The die holder 30 surrounds the outer circumference of the backing plate 40.
As shown in
As shown in
The width of the holder hole 31 and the width of the third partition wall 32 are, for example, constant in the axial direction of the holder hole 31. The width of the holder hole 31 is greater than the minimum width of the backing hole 41 and smaller than the maximum width of the backing hole 41. The width of the third partition wall 32 is greater than the width of the first partition wall 62 and smaller than the maximum width of the second partition wall 42.
As shown in
As shown in
The punches 80 are respectively inserted into and withdrawn from the die holes 61, in synchronization with the reciprocating motion of the slide of the pressing device in the vertical direction. This causes the workpiece W to be punched out, forming through-holes. The scrap generated during the punching of the workpiece W passes through the die holes 61, backing holes 41, and holder holes 31 in that order, and is discharged outside the lower die assembly 21. Pieces of scrap are discharged through the backing holes 41 and the holder holes 31, which are respectively connected to the die holes 61.
A press die apparatus that is different from the press die apparatus 20 is used to form through-holes, defining the central hole 12, in the workpiece W. Subsequently, the iron core piece 11a including each through-hole is punched out of the workpiece W.
The operation and advantages of the present embodiment will now be described.
In this configuration, the die holes 61 are respectively connected to the backing holes 41. This eliminates the need to provide partition walls corresponding to all the first partition walls 62 on the backing plate 40. Each second partition wall 42, which separates the backing holes 41 from each other, includes the widened section 43. The maximum width of the widened section 43 is larger than the width of the first partition wall 62 of the die 60. Thus, even when the die holes 61 are proximate to each other, a reduction in the width of the second partition wall 42 is limited. This limits a reduction in the strength of the backing plate 40 and consequently limits a reduction in the strength of the press die apparatus 20.
In this configuration, the scrap discharged into the backing holes 41 slides down along the inclined surfaces 44, making it easier to discharge the scrap outside the backing holes 41. This improves the scrap discharge efficiency in the press die apparatus 20.
This configuration reduces the minimum width of the end of the widened section 43 on the side where the die 60 is located. As a result, when the distance between the die holes 61 decreases so that the widths of the first partition walls 62 decrease, the distance between the backing holes 41 is still reduced. This limits a reduction in the strength of the backing plate 40 while decreasing the distance between the backing holes 41.
In this configuration, even when the die holes 61 are proximate to each other, a reduction in the width of each third partition wall 32, which separates adjacent ones of the holder holes 31 from each other, is limited. This limits a reduction in the strength of the die holder 30 and consequently limits a reduction in the strength of the press die apparatus 20.
This configuration allows the press die apparatus 20 to be used to form multiple through-holes arranged in an annular pattern on the workpiece W. Thus, the press die apparatus 20 can be used to manufacture the rotor core 11, which has the magnet accommodating holes 13 arranged in an annular pattern, and the stator core of a rotating electric machine that has multiple slots arranged in an annular pattern.
To improve the durability of the backing plate 40, reducing the degree of stress concentration on the second partition wall 42 is preferable.
In the above configuration, the first partition wall 62 and the second partition wall 42 face each other, with the gap G in between. This arrangement reduces or eliminates the contact area between the first partition wall 62 and the second partition wall 42. Thus, the load applied to the die 60 during the use of the press die apparatus 20 is less likely to act directly on the second partition wall 42. This reduces the degree of stress concentration on the second partition wall 42.
The present embodiment may be modified as follows. The present embodiment and the following modifications can be combined as long as they remain technically consistent with each other.
The rotor core 11 may have cooling passages that extend through the rotor core 11 in the axial direction, located radially inside the magnet accommodating holes 13. In this case, as shown in
There may be no gap G between the edge 45 and the lower surface of the die 60. In this case, since the entire edge 45 is located at the same height as the upper surface of the backing plate 40, the entire edge 45 is in contact with the first partition wall 62.
The die holes 61 do not have to be arranged in an annular pattern; for example, they may also be arranged straight. That is, the press die apparatus 20 does not have to be used to form the iron core pieces 11a. For instance, it may also be used to form through-holes arranged straight in the workpiece W.
The width of the holder hole 31 may increase as it extends further away from the backing plate 40. In other words, the width of the third partition wall 32 may decrease as it extends further away from the backing plate 40. Even in this case, the maximum width of the third partition wall 32 is preferably greater than the width of the first partition wall 62.
The width of the third partition wall 32 may be less than or equal to the width of the first partition wall 62.
The edge 45 may be formed by two inclined surfaces 44 and a flat surface that connects the two inclined surfaces 44 to each other. In this case, the width of the upper end of the widened section 43 is increased.
The portion of the inner surface of each backing hole 41 that defines the widened section 43 may have a curved surface that protrudes on either one side or the other in the circumferential direction C.
The width of the die hole 61 may increase as it approaches the backing plate 40. In other words, the width of the first partition wall 62 may decrease as it approaches the backing plate 40. In this case, the maximum width of the widened section 43 is also preferably greater than the maximum width of the first partition wall 62.
The width of the widened section 43 may increase in a stepwise manner as it extends away from the die 60. In this case, the portion of the inner surface of the backing hole 41 defining the widened section 43 is a stepped inner surface.
As shown in
Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-181955 | Oct 2023 | JP | national |
