JP2015150605A - Rolling die structure for double-end threaded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce rolling failures to a columnar screw stock when forming a double-end threaded body so as to be capable of performing mass production of the double-end threaded body in a high accuracy.SOLUTION: A double-end threaded body D is rolled by use of a die member 10 including a stiff surface which is relatively displaced with respect to a screw stock B while being brought into press-contact with the screw stock B. The die member 10 comprises: a precursor processing region Q including a region gradually approaching to the axis of the screw stock B along a direction of the relative-displacement, and a region gradually separating from the axis thereof in a virtual surface 22 obtained by connecting outermost parts of the surface; and a double-end threaded part formation region U where a plurality of recess parts 30, which are an approximately parallelogram shapes when viewed in the direction normal to the virtual surface 22 and are recessed from the virtual surface 22, are arranged along the direction of the relative-displacement.

Description

  The present invention relates to a rolling die structure and the like for efficiently and stably producing both screw bodies having a right screw portion and a left screw portion on the same region in the axial direction of the screw portion by rolling. .

  Conventionally, when a male screw having only one of a right-handed screw or a left-handed screw is manufactured by rolling, a screw material that is a metal cylindrical rod-like body also called a blank is formed with a plurality of strips. While pressing with a die member that becomes a plurality of rigid flat plates, rigid cylinders or rigid cylinders on the surface, the screw material and the die member are relatively displaced to form a screw thread or a screw groove while plastically deforming the screw material surface. It is common. The strips formed on the die member are formed in a state where the cross section is formed in a desired shape, for example, a substantially triangular shape, substantially parallel to each other, and having a lead angle.

  As a male threaded body, both threaded bodies having a right threaded part and a left threaded part on the same region in the axial direction of the threaded part of the male threaded body are known, and attempts have been made to produce this by rolling. (See Patent Document 1).

  According to Patent Document 1, by optimizing the shape of the parallelogram-shaped recess that becomes the strip of both screw bodies recessed in the die member, the shaft shape after rolling is relatively stable, and The strip can be formed with high accuracy. However, in the future, there is a demand for a technology that enables mass production of both screw bodies with higher accuracy by simple setting of a rolling device.

JP 2013-43183 A

  The present invention solves the above-mentioned problems, i.e., reduces both rolling failure of the cylindrical screw material when forming both screw bodies, and enables mass production of high-precision both screw bodies. An object is to provide a die structure for rolling a threaded body.

  In order to solve the above problems, the means adopted by the die structure for rolling both screw bodies includes a die member having a rigid surface that is relatively displaced while being pressed against the screw material, and the die member is formed on the surface of the die member. Precursor processing region having a region gradually approaching the axis of the screw material along the direction of relative displacement on the virtual surface obtained by connecting the outermost parts, and a region gradually separating from the axis And a threaded portion forming region having a substantially parallelogram shape in a normal direction view of the virtual surface, and a plurality of concave portions recessed from the virtual surface being arranged in a plurality along the direction of relative displacement. It is characterized by providing.

  In relation to the above means, at least a part of the precursor processing region in the die member is present on the upstream side when the screw material is relatively displaced with respect to the both screw forming regions. .

  In relation to the above means, the precursor processing region and the two threaded portion forming regions in the die member are arranged independently.

  In relation to the above means, the arrangement pitch of the plurality of concave portions arranged linearly along the direction of relative displacement in the both screw forming regions is different from the approaching region and the separation in the precursor processing region. It is characterized by being set to an integral multiple of the pitch between the areas to be processed.

  According to the present invention, it is possible to reduce the rolling failure of a cylindrical screw material when forming both screw bodies, and to achieve an excellent effect of enabling mass production of both screw bodies with high accuracy.

The outline of the die structure for both screw body rolling adopted in the embodiment of the present invention is shown, (A) is flat die rolling, (B) is rolling rolling, (C) is planetary rolling. FIG. (A) is a front view showing a die member having the same die structure, and (B) is a side view. (A) is a front view explaining arrangement | positioning of the recessed part of the both screw part formation area in the same die structure, (B) is a figure which shows the deformation | transformation process of the screw raw material by the both screw part formation area, (C) FIG. 3 is an enlarged sectional view showing a sectional shape of the concave portion. (A) thru | or (C) is a side view which shows the process of processing a screw raw material by the precursor process area | region in the same die structure. (A) is a side view showing a part of both screw bodies in an enlarged manner, (B) is a cross-sectional view showing the cross-sectional area of the highest apex of the thread in both screw regions, and (C) the both screw bodies FIG. (A) is a side view showing a part of both screw bodies in an enlarged manner, (B) is a sectional view showing a cross-sectional area of a crossing portion of screw threads in both screw regions, and (C) the both screw bodies. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, a die structure for rolling both screw bodies according to an embodiment of the present invention will be described. The die structure for rolling both screw bodies deforms the surface of the screw material B while being pressed against the cylindrical screw material B and relatively displaced in a direction orthogonal to the axial direction of the screw material B, It is for rolling both screw bodies D which have a right-hand thread part and a left-hand thread part on the same area | region in a direction.

  As a rolling method, so-called flat die rolling using two plate-shaped die members 10 shown in FIG. 1 (A), or two or more circular or cylindrical round shapes shown in FIG. 1 (B). So-called rolling rolling using the die members 12 and 12 together, as shown in FIG. 1 (C), one is an arc-shaped die member 13 and the other is a cylindrical or cylindrical round die member 12 so-called rolling. There is planetary rolling. Hereinafter, in the present embodiment, the case of a flat die structure will be specifically described. However, the present invention can be applied to any other rolling methods not exemplified in these.

  The rolling die structure of the present embodiment includes two or more die members 10 that are pressed against the screw material B, and each die member 10 has a rigid surface 20. While these two or more die members 10 are pressed against the screw material B, the rigid surfaces 20 thereof are displaced relative to each other and at the same time relative to the screw material B.

  As shown in FIG. 2A, the rigid surface 20 of the die member 10 has a concave surface 30 on a virtual surface 22 obtained by connecting the outermost portions of the rigid surface 20 (portions that are closest to the screw material B). A plurality of threaded portion forming regions U provided in a plurality of independently aligned manners are provided. The concave portions 30 of both screw portion forming regions U have a substantially parallelogram shape when viewed in the normal direction, and are recessed from the virtual surface 22 as shown in FIG. Here, the virtual surface 22 has a planar shape in the case of the plate-shaped die member 10, a cylindrical surface shape in the case of the round die shape, and a partial cylindrical surface (arc surface) shape in the case of the arc-shaped die shape. It is desirable to set to.

  As shown in FIG. 3A, each recess 30 is formed in a substantially parallelogram shape when viewed from the normal direction of the virtual plane 22, and preferably has a substantially rhombus shape. Thus, if it sets to a substantially rhombus shape, each screw pitch in the right-hand thread part and left-hand thread part of the both screw bodies D to be rolled can be made equal to each other.

  Each of these concave portions 30 is formed such that two or more corner portions 31, 31 of the substantially parallelogram-shaped four-corner corresponding portions in the normal direction view are rounded in the normal direction view as shown in FIG. Is done. In the present embodiment, all the corners 31, 31, 32, 32 of the substantially parallelogram-shaped four-corner corresponding portion are rounded. The two or more corner portions 31, 31 are preferably set in a diagonal position, and in particular, the direction in which the screw material B rolls, that is, the relative displacement, of the two or more corner portions 31, 31 is preferable. If it is set as a diagonal position in the direction of, it is preferable that the facet generated during rolling is likely to flow out of the recess 30 during relative displacement.

  As shown in FIG. 3 (B), the concave portion 30 has a virtual substantially quadrangular pyramid-shaped hole shape with the opening surface as one constituent surface, and the central top portion of the substantially quadrangular pyramid shape is A deepest portion 34 of the recess 30 is formed. More preferably, the shape is such that the deepest portion 34 of the recess 30 has a substantially flat bottom 35. By doing so, the bottom 35 is widened, and it is easy to flow out without clogging the generated facet, and the highest peak of the thread M of both screw bodies D does not form an acute angle in the direction perpendicular to the axis of both screw bodies D. Therefore, the stability when the female screw body is screwed to the both screw bodies D can be improved. Moreover, the product precision of the both screw bodies D obtained by mass production can be remarkably improved.

  When the screw material B is relatively moved in the both screw portion forming region U, the shaft portion E of the screw material B is gradually formed, and both screw threads are formed around the shaft portion E.

  As shown in FIG. 3 (C), these recesses 30 have a substantially parallelogram shape in which the peripheral portion 33 is rounded as in, for example, R processing in the cross-sectional shape along the normal direction of the virtual surface 22. It forms round along the circumference | surroundings of the peripheral edge 33 which comprises. In this way, by rounding the periphery 33 of the recess 30 over the circumference of the periphery 33, the surface of the die member 10 and the screw material B are scraped off from the screw material B during rolling. Therefore, it is possible to prevent the generation of the facet that occurs. In addition, this invention is not limited to this, For example, as shown to FIG 3 (D), you may make it trapezoid shape and can also make it V shape.

As shown in FIG. 3A, the substantially parallelogram-shaped concave portion 30 in the normal direction of the virtual surface 22 has at least one diagonal distance W among its diagonal lines, the radius of the screw blank B as R0, and the circumference. When the rate is π, it is set to be 2πR0 or less. Preferably, when the root diameter of both screw bodies D obtained by carrying out the present invention is d _R (see FIG. 5), the diagonal distance W of at least one of the diagonal lines of the substantially parallelogram forming the recess 30 is πd. _R or less. More preferably, setting the diagonal distance of a diagonal line parallel to at least the relative displacement direction of the diagonal of the parallelogram forming the recess 30 in the following [pi] d _R. By setting in this way, the screw pitch of the right screw portion and the left screw portion can be set to be equal, and a highly accurate double screw body D can be obtained.

In addition, as shown in FIG. 3A, the opening of the recess 30 sets one diagonal distance of the substantially parallelogram in the normal direction of the virtual surface 22, preferably a relatively long diagonal distance W in the relative displacement direction. The other diagonal distance, preferably the diagonal distance F in the direction orthogonal to the relative displacement direction is set to be relatively short. The concave portion 30 has a volume v of the concave portion 30, a circumferential ratio π, a concave pitch of the concave portions 30 in a direction orthogonal to the direction of relative displacement of the die member 10, and a valley diameter of both screw bodies D. _R (see FIG. 5), where h is the depth of the deepest portion 34 of the recess 30, the set range of the volume v of the recess 30 is defined by πpd _R h / 7 ≦ v ≦ πpd _R h / 5. It is preferable to configure so that. If it is set to be smaller than this range, the thread M is too thin, becomes too small and the strength is insufficient, or when the female screw body is screwed into the both screw bodies D which are male screws obtained by the practice of the present invention. The play becomes too big and the backlash becomes too big. Conversely, if it is set to be larger than this range, the thread M will be too thick or too large, and play will be reduced when the female screw body is screwed into the both screw bodies D, which are male screws obtained by the practice of the present invention. After that, it becomes difficult to screw or cannot be screwed, or it is difficult to roll the thread M with high accuracy.

  If rolling is performed using the die member 10 having the die structure for rolling the double screw body D as described above, the high-precision double screw body D can be efficiently mass-produced.

  The rigid surface of the die member has a precursor processing region on a virtual surface 22 obtained by connecting between the outermost portions (portions that are closest to the screw material B) of the rigid surface. This precursor processing region is for processing into a precursor cross-sectional shape (hereinafter referred to as a substantially elliptical shape) such as an elliptical or oval cross-sectional shape, for example, and both screws following this In the part forming region U, a precursor shape for facilitating the formation of both screw parts is formed. In particular, the rigid surface 20 of the die member 10 that processes the precursor cross-sectional shape into a substantially elliptical shape has a precursor processing region Q on the virtual surface 22 as shown in FIG.

  As shown in FIG. 4, the precursor processing region Q gradually approaches the axis E1 of the screw material B while maintaining the surface state of the virtual surface 22 along the direction of relative displacement with the screw material B. The approaching region Q1 that repeats and the separation region Q2 that gradually separates from the axis E1 are repeated. Therefore, as shown in FIG. 4A, the process of compressing the screw material B, which initially has a circular shape in cross section, in the approach region Q1 is repeated in the same phase. Thus, the cross section is non-circular having a major axis and a minor axis. In addition, although the case where the approach area Q1 and the separation area Q2 are curved surfaces is illustrated here, the present invention is not limited to this. For example, as shown in FIG. 4 (D), the projections and depressions may have a trapezoidal cross section, or may be sawtooth-like projections and depressions.

  As shown in FIG. 2A, at least a part of the precursor processing region Q in the die member 10 exists on the upstream side when the screw material B is relatively displaced with respect to both screw portion forming regions U. Desirably, the precursor processing region Q and both screw portion forming regions U are disposed independently. If it does in this way, before the screw raw material B approachs into both the thread part formation area | region U, it will become possible to deform | transform into the substantially elliptical shape in advance in the precursor process area | region Q. Of course, a part or all of this precursor processing region Q may overlap with both screw portion forming regions U. In the case of stacking, the thread material B is formed simultaneously while the thread material B is elliptically processed.

  The deformation pitch between the approach region Q1 and the separation region Q2 in the precursor processing region Q with respect to the arrangement pitch PU of the plurality of recesses 30 arranged on a straight line along the direction of relative displacement in both screw portion formation regions U PQ is set to an integral multiple thereof, here four times. In addition, since the parallelograms are arranged in an oblique lattice shape, the recesses 30 have a lattice pitch PX of the plurality of recesses 30 arranged in a zigzag shape, which is a half of the arrangement pitch PU of the recesses 30 arranged on a straight line. Become one. Furthermore, the phase of the deformation pitch PQ and the phase of the arrangement pitch PU are in agreement between the precursor processing region Q and both screw portion forming regions U adjacent thereto. If it does in this way, rolling of the screw raw material B to the both thread part formation area | region U from the precursor process area | region Q will be performed smoothly.

  As shown in FIGS. 5B and 6B, in both screw bodies D, a pair of screws having a phase difference of 180 degrees is characteristic of both screw regions formed by overlapping the right and left screws. The total cross-sectional area S1 (see FIG. 5 (B)) of only the thread M at the highest peak of the peaks M, M and the threads M, M intersect each other at 90 degrees in the circumferential direction with respect to the highest peak. It can be mentioned that the total cross-sectional area S2 (see FIG. 6B) of only the thread M at the intersecting portion is significantly different. That is, in the rolling of both screw bodies D, the thread material B is deformed so that the shaft portion E approximates a perfect circle, but the surrounding screw thread M has a volume near the highest apex and 90 It must be rolled so that the volume in the vicinity of the intersecting part is different. Therefore, if rolling is performed using both threaded portion forming regions U with the thread material B having a perfect circular section, the threaded material B near the intersection is thinned and the threaded material B near the highest peak is increased. Depending on the material of the screw material B, the flow of such a material may be difficult.

  Accordingly, as in the present embodiment, in the precursor processing region Q upstream of the two screw portion forming regions U, the screw material B has a long axis at a location where it can be the highest peak of the future screw thread M. By deforming into a substantially elliptical shape with the short axis as the place where the thread M can be crossed, the amount of plastic deformation of the screw material B can be reduced in the two screw part forming regions U. In addition, the precursor processing region Q and both screw portion forming regions U are integrally disposed on the die member 10, and the deformation pitch PQ (short axis and long axis pitch) of the precursor processing region Q and both screws The phase of the highest peak of the thread in the part forming region U and the pitch of the intersecting part (a quarter of the array pitch PU) are matched. As a result, by performing a series of rolling operations together with elliptical or oval machining and screw thread machining, it becomes possible to roll both screw regions with extremely high accuracy with extremely high work efficiency. .

  As shown in FIG. 2 (A), the rigid surface 20 of the die member 10 is a planar cylinder (column) that is disposed adjacent to both screw portion forming regions U in a state of being displaced in the axial direction of the screw material B. The portion forming region K may be provided. The cylindrical portion forming region K rolls the cylindrical region of the both screw bodies D of FIGS. 5 and 6.

  The rolling method of both screw bodies D using the rolling die structure of this embodiment is relatively displaced in a direction perpendicular to the axial direction of the screw material B while being pressed against the cylindrical screw material B. Then, the surface of the screw material B is deformed to roll the both screw bodies D having the right screw portion and the left screw portion on the same region in the axial direction.

  When rolling using a plate-shaped die member 10 as in this embodiment, as shown in FIG. 1A, one flat die member 10 is fixed and the distance between the outermost surfaces is fixed thereto. The other flat die member 10 is arranged so as to be a predetermined distance d, and the other flat die member 10 is relatively displaced while maintaining the distance d.

  As shown in FIG. 3B, in both threaded portion forming regions U, the distance between the central axis E1 of the screw material B and the virtual surface 22 is decreased from the upstream side where the screw material B is relatively displaced toward the downstream side. It can also be set. In that case, the virtual surfaces 22 of the pair of opposed flat die members 10 may be set non-parallel so that the distance from each other gradually decreases in the direction in which the screw material B rolls.

  Further, as shown in FIG. 1B, in the case of so-called rolling rolling using two or more round die members 12, 12 having a columnar shape or a cylindrical shape, the two round die members 12, 12 are The rotating shafts are held in parallel so that the distance between the outermost surfaces is a predetermined distance d. Then, each of them can be rotated while maintaining the distance d. At this time, the respective round die members 12, 12 may be reversely rotated or rotated in the same direction.

  In addition, as shown in FIG. 1C, in the case of rolling by a so-called planetary method in which one is an arc-shaped die member 13 and the other is rolled using a columnar or cylindrical round die member 12, The arc-shaped die member 13 is fixed, and the other round die member 12 is rotatably held so that the distance between the outermost portions is a predetermined distance d. The rigid surfaces 20 and 20 are disposed so as to be relatively displaceable while maintaining the distance d.

  Further, according to the die structure of the present embodiment, as shown in FIG. 2A, the screw material B can be processed into an oval shape or an oval shape using the precursor processing region Q of the die member 10. .

  More specifically, the screw material B is deformed in advance into a substantially elliptical shape before the screw material B enters the both screw portion forming regions U.

  At that time, in the precursor processing region Q upstream of the both screw portion forming regions U, the thread material B is a long axis at a place where it can be the highest peak of the future thread M, and the intersection of the future thread M It is deformed into a substantially elliptical shape so that the place where it can become a short axis. As a result, the amount of plastic deformation of the screw material B can be reduced in the both screw portion forming regions U. In addition, the precursor processing region Q and the both screw portion forming regions U are integrally disposed on the die member 10, and the deformation pitch PQ (short axis and long axis pitch) of the precursor processing region Q and both screws Ellipse or oval machining and thread machining are performed in a series of rolling operations while matching the phases of the highest peak of the thread in the part forming region U and the pitch of the intersection (a quarter of the arrangement pitch PU). Do it all together. As a result, it is possible to roll both screw regions with extremely high accuracy with extremely high work efficiency.

  Although the rolling die structure of the both screw bodies D described above has been described, of course, the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Die member 20 Rigid surface 22 Virtual surface 30 Recessed part 31 Corner part 35 Bottom part 50 Valley part B Screw material D Double screw body E Shaft part K Cylindrical part formation area M Screw thread Q Precursor processing area U Both screw part formation area

Claims (4)

A die member having a rigid surface that is relatively displaced while being pressed against a screw material,
The die member is
A precursor having a region gradually approaching the axis of the screw material along the direction of relative displacement on a virtual surface obtained by connecting the outermost portions of the surface, and a region gradually separating from the axis. Body processing area,
Both threaded portion forming regions having a substantially parallelogram shape when viewed from the normal direction of the virtual surface, and a plurality of concave portions recessed from the virtual surface are arranged along the relative displacement direction. Characterized by comprising,
Die structure for rolling both screw bodies. At least a part of the precursor processing region in the die member is present on the upstream side when the screw material is relatively displaced with respect to the both screw forming regions,
The die structure for rolling both screw bodies according to claim 1. In the die member, the precursor processing region and the both screw forming regions are independently arranged,
A die structure for rolling both screw bodies according to claim 1 or 2. The arrangement pitch of the plurality of recesses arranged linearly along the direction of relative displacement in the two threaded portion forming regions is the pitch between the approaching region and the separating region in the precursor processing region. It is set to an integer multiple,
A die structure for rolling both screw bodies according to any one of claims 1 to 3.

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