JPH0919719A - Method for correcting end face of circular cross-section shaft like member and rolling die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for effectively correcting the shape and dimension of the end face of a shaft like member and a die therefor. SOLUTION: By gripping a circular cross-section shaft like blank 30 between a pair of rolling dies and rolling it, the end part of the shaft like blank 30 is applied with a load from the outside in the radius direction and the flow of the material is generated partially, the excess margin 31 generated with the flow of the material is moved to the central part of the end part of the blank 30 into the state of projecting in the axial direction, the end face 11 generated on the outer circumference side than the excess margin 31 projecting to the axial direction is made as the finishing face of the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for straightening an end surface of a shaft member having a circular cross section such as a piston pin, and a rolling die for the same.

[0002]

2. Description of the Related Art A full floating type piston pin used in a gasoline engine or the like requires a high dimensional accuracy in a dimension between end faces, that is, an axial length. Therefore, conventionally, the piston pin is manufactured through the following steps. ing. First, a material cut into a predetermined size from a coil is processed into a hollow cylindrical shape from a multi-stage header that is pressed at a plurality of consecutive stations, and the end surface of the material thus obtained is subjected to cutting work to obtain a shape. And finished the dimensions.

As a method of replacing cutting, a method of press working is known. As shown in FIG. 11, the hollow cylindrical material 1 is formed by pressing a pair of press dies 2a, 2
Set between b and apply a load in the axial direction while restricting the outer periphery by these press dies 2a and 2b, and the surplus 3 due to the deformation is placed at the center of the end face that does not hinder the function and assembly. It is a method of producing and thereby finishing the shape and dimensions.

[0004]

Among the above-mentioned conventional end face straightening methods, the method by cutting has a problem that it takes time to set and process a rough material, the material yield is low, and the productivity is poor. .

On the other hand, in the method of press working,
Although such an inconvenience does not occur, since a load is applied to the entire rough material to cause deformation, a large load is required, and there is a possibility that the equipment becomes large. Further, a surplus due to applying a load in the axial direction may occur as a protrusion 4 on the outer peripheral surface as shown in FIG. In such a case, the step of removing the protrusion 4 increases, and even if the protrusion 4 is removed in the above-described multi-stage header, the fracture surface 5 associated therewith causes the outer periphery of the product as shown in FIG. It may occur on the surface, and this may cause a decrease in strength.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for straightening an end surface of a shaft-shaped member having a circular cross section and a rolling die for carrying out the method with good productivity. To do.

[0007]

In order to achieve the above-mentioned object, the method of the present invention involves sandwiching a shaft-shaped rough material having a circular cross section between a pair of rolling dies and rolling it. By this, a load is applied from the outside in the radial direction to the end of the shaft-shaped material to partially cause the material to flow, and the surplus generated by the flow of the material is applied to the center of the end of the rough material. The method is characterized in that the end surface formed on the outer peripheral side of the extra thickness projected in the axial direction is used as the finished surface of the product while being moved to the axially projected state.

Further, in the method of the present invention, the excess thickness is generated by applying a cutting load to the end of the shaft-shaped rough material with a narrow width along a plane perpendicular to the central axis, and then the excess thickness is generated. It is also possible to apply a load to and move the surplus so as to project in the axial direction toward the center of the end of the rough material.

Further, according to the rolling die of the present invention, by sandwiching a shaft-shaped rough material having a circular cross section and moving the rough material in a direction in which the rough material is rolled, a partial plastic deformation is caused at an end portion of the rough material. A rolling die that is formed into a predetermined shape and size by projecting to the rough material side at a position corresponding to the end of the rough material in a state where the rough material is sandwiched and its projecting height gradually increases. A thin plate-shaped ridge is formed, and the side surface of the ridge that comes into contact with the surplus formed at the end of the rough material is twisted so as to be gradually parallel to the central axis of the rough material. It is characterized in that it is formed in a shape.

According to the method of the present invention, the shaft-shaped rough material is
It is sandwiched between a pair of rolling dies and is rolled in that state to undergo plastic working on the ends. That is, a load is applied to the end portion in the radial direction from the outside, and a partial flow of the material is generated accordingly, and the surplus is gradually moved to the center portion of the end portion. The edge surface newly generated in this way is used as a finished surface of the product, and the edge surface is corrected.
Therefore, the shape of the end face and the interval between the end faces, that is, the axial length is determined by the shape and size of the processed portion in the rolling die, and as a result, the end face can be corrected quickly and accurately.

Further, in the present invention, if the excess thickness is generated by applying a cutting load to the end of the rough material and the load is applied to the excess thickness to move to the center of the end, the excess thickness of the excess thickness is Since the load is small, the load required for rolling can be low, the life of the mold is extended, and slippage between the rough material and the die is reduced, so that inconvenience such as peeling of the rough material can be prevented. it can.

Further, in the rolling die of the present invention, since the ridges that bite into the rough material have a thin plate shape, it is possible to apply a cutting load to the ends of the rough material to generate a surplus, and The surplus is pushed by the side surface of the ridge and turned so as to be gradually parallel to the central axis of the rough material, and finally moved to the center side of the end portion. Therefore, according to this rolling die, after the surplus is generated, the load is applied only to the surplus to finish the product into a predetermined shape, so that the molding load can be low and the relative between the rough material and the die. It is possible to reduce the mechanical slippage, improve the mold life, and prevent peeling of the rough material.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described more specifically with reference to the drawings. First, the object to be machined in the example shown in the figure will be described. In this example, the piston pin 10 shown in FIG. 2 is the object, which is a hollow shaft-shaped member, the outer diameter of which is defined in a pre-process not shown. It has been processed to the dimensions of. The distance between the shaft end faces 11, that is, the axial length W1, the length W2 of the outer peripheral face 12, the radial dimension H1 of the taper portion 13 at the shaft end portion, and the radial dimension H2 of the end surface 11 including the taper portion 13. And are finished by end face straightening. Further, as the rough material of the piston pin 10, a hollow cylindrical member made of steel, the outer diameter of which is adjusted by the above-described multistage header or the like, is used.

FIG. 1 shows one of a pair of rolling dies 20 for carrying out the method of the present invention. The rolling die 20 is a so-called flat rolling die, and as an example, a ridge 22 is formed on both right and left sides of a rectangular plate-shaped base portion 21. These ridges 22 are for causing plastic deformation at the ends of the rough material.
Two side surfaces facing each other are formed as inclined surfaces 23 so as to form the tapered portion 13. The distance between the start end of the inclined surface 23, that is, the boundary between the inclined surface 23 and the base portion 21 is set to be the same as the length W2 of the outer peripheral surface 12 of the piston pin 10 to be obtained. Further, the inclination angle θ of the inclined surface 23 gradually increases from one end side to the other end side in the longitudinal direction of the base portion 21. Therefore, the height of the protrusion 22 gradually increases as the inclination angle θ increases.

Further, the inclination angle θ of each inclined surface 23 is set to the maximum angle that coincides with the angle of the taper portion 13, and the front side (that is, the portion where the inclination angle θ is small) from the point where the maximum angle is reached. On the other side), it is set to its maximum angle. And the inclination angle θ of each inclined surface
A second protrusion 24 is formed at a position where the angle is the same as that of the tapered portion 13. This second ridge 24
Is for molding a part of the tapered portion 13 formed by the inclined surface 23 into an end surface perpendicular to the axial direction of the rough material, and therefore a surface perpendicular to the base portion 21 (hereinafter, It is formed by a vertical surface 25) and a surface orthogonal to the vertical surface 25, that is, a surface parallel to the base portion 21 (hereinafter, temporarily horizontal surface) 26.

The width of the vertical surface 25 forming the second protrusion 24 (width measured in the direction perpendicular to the base portion 21)
Is formed so as to be gradually larger, and accordingly, the horizontal surface 26 is formed so that the width thereof is gradually increased. Further, the height of the intersection of the vertical surface 25 and the inclined surface 23, that is, the height of the starting end of the vertical surface 25 from the base portion 21 is set to be the same as the radial width H1 of the tapered portion 13 of the piston pin 10. . In other words, the portion of the inclined surface 23 that is closer to the base portion 21 than the second protrusion 24 is a surface that substantially forms the tapered portion 13.

The maximum width of the vertical surface 25 is set to be the same as the radial dimension H2 of the end surface 11 of the piston pin 10 including the tapered portion 13. Further, the distance between the vertical surfaces 25 on the left and right inclined surfaces 23 is set to be the same as the axial length of the piston pin 10, that is, the distance W1 between the end surfaces 11 of the piston pin 10. In addition, in FIG. 3, in order to explain the shape of the second protrusion 24, the line AA of FIG.
The cross sections along the line BB and the line CC are respectively shown.

The method of the present invention using the above-mentioned rolling die 20 will be described below. FIG. 4 schematically shows the progress of the processing. First, a rough column previously formed in a hollow cylindrical shape is used. From the pair of rolling dies 20, the ridges 22
Place it between the parts that do not project. When the rolling dies 20 are linearly moved in the opposite directions in that state, the rough material 30 rolls between these rolling dies 20,
At the same time, the left and right ridges 22 of the rolling die 20 apply a load to the shaft end of the rough material 30 from the outside in the radial direction. That is, each of the inclined surfaces 23 presses the shaft end portion of the rough material 30, so that the corner portion of the shaft end portion is deformed into a taper shape. Along with this, a surplus 31 is generated, but this surplus 31 is moved to the center side at the end of the rough material 30 by the inclined surface 23.

When the corner portion of the shaft end portion of the rough material 30 is formed to the desired taper angle in this way, the inclined surface 2 is formed.
The second ridge 2 provided at the maximum inclination angle portion of 3
4 begins to act on the rough material 30. That is, the second protrusion 24 starts to bite into the tapered shaft end portion of the rough material 30. As described above, the second ridge 24 is composed of the vertical surface 25 perpendicular to the base portion 21 and the horizontal surface 26 orthogonal to the vertical surface 25. Deforms in a right-angled cross section as shown in FIG. More specifically, the vertical surface 25 presses the tapered shaft end portion of the rough material 30 in a direction perpendicular to the central axis thereof, and as a result, the rough material 30 is formed with the end surface 11 perpendicular to the axial direction. To be done. Further, since the horizontal surface 26 increases in distance from the base portion 21 as the width of the vertical surface 25 increases, the surplus material 31 in the rough material 30 is pushed by the horizontal surface 26 and the end portion of the rough material 30 is pushed. Moved to the center.

The spacing between the new left and right end faces 11 thus generated is defined by the vertical surface 25 of the rolling die 20.
It is the same as the distance W1 between them, and the axial length W2 of the outer peripheral surface of the rough material 30 is defined by the distance between the starting ends of the inclined surfaces 23, that is, the width of the flat surface of the base portion 21, and the rough material 30
The width in the radial direction of the tapered corner portion of the inclined surface 2
3 is the same as the dimension H1 in the height direction on the lower side of the vertical surface 25 in FIG.
The width of the end surface of 0 from the outer peripheral surface is the same as the dimension H2 of the vertical surface 25 from the base portion 21. As a result, the rough material 30 is deformed by the inclined surface 23 and deformed by the second protrusion 24 to correct the shaft end portion, and the piston pin 10 having the desired shape and size is obtained.

In the above-mentioned embodiment, the taper angle of the tapered portion formed at the end of the rough material 30 is gradually formed to be a regular angle. However, instead of this, from the beginning of the processing. You may form in a regular taper angle. An example will be described below.

FIG. 5 shows a part of one of a pair of flat-rolling dies 40 used for the processing, in which a ridge 42 having the same shape is formed on both left and right sides of a rectangular plate-shaped base portion 41. Has been formed. The ridge 42 has a triangular cross section,
The inclination angle θ of the inner inclined surface 43 of the inclined surfaces is set to be the same as the taper angle of the tapered portion 13 of the piston pin 10. The distance between the starting ends of the inclined surfaces 43 of the left and right protrusions 42, that is, the intervals between the intersections with the base portion 41, is set to be the same as the length W2 of the outer peripheral surface 12 of the piston pin 10. Further, the height of the ridge 42 gradually increases from one end side to the other end side in the longitudinal direction of the base portion 41, and the maximum height thereof is the radial direction of the taper portion 13 of the piston pin 10. Is set to be the same as the width H1.

Further, the other side surface of the ridge 42, that is, the outer side surface 44, extends from the position where the height of the ridge 42 reaches the maximum height to the front side (the other end side in the longitudinal direction of the base portion 41). It is formed so that it gradually becomes horizontal toward it. This state is shown in FIG. 6, and the cross-sectional shape of the ridge 42 is changed from a triangle to a quadrangle, and finally, the ridge 42 is configured to have a trapezoidal shape with a maximum height. Further, as shown in FIG. 5, the side surface 44 thereof is gradually higher than the top of the protrusion 42 while being horizontal with respect to the base portion 41, and the maximum height from the surface of the base portion 41 is the piston pin. 10
Is set to be the same as the radial dimension H2 of the end surface 11 including the tapered portion 13 from the outer peripheral surface 12. The surface extending from the top of the ridge 42 to the upper side in the drawing is the base portion 41.
Is a surface (hereinafter, referred to as a vertical surface) 45 that is perpendicular to the vertical surface 45. The distance between the vertical surfaces 45 of the left and right ridges 42 is the same as the distance W1 between the end surfaces 11 of the piston pin 10. It is set.

When the end face of the rough material 30 is corrected by the rolling die 40, the rough material is sandwiched between the pair of rolling dies 40, and the rolling dies 40 are linearly moved in the opposite directions in this state. Rolling the rough material 30 by moving it is the same as in the above-described embodiment. Rough material 30 in that case
The deformation process of the end portion of is shown in FIG. As described above, in the ridge 42, the inclination angle of the inner inclined surface is the taper portion 1.
Since the taper angle is the same as the taper angle of 3 and the height is gradually increased, the ridge 42 of the rough material 30 gradually bites into the end of the rough material 30 as the rough material 30 rolls. In this way, the rough material 3
A taper portion is gradually formed at the shaft end portion of 0, and at the same time, an excess thickness 31 is generated.

When the rough material 30 relatively moves to the position of the maximum height of the ridge 42 in the rolling die 40, the ridge 42
The bite of (1) is finished, and the side surface 44 starts processing the extra thickness 31 before and after that. That is, the side surface 44 is
As described above, since it gradually changes to a so-called horizontal plane that extends horizontally from the top of the ridge 42, the extra thickness 31 is pressed by the side surface 44 thereof and gradually changes its direction so as to be parallel to the central axis of the rough material 30. To be Further, since the side surface, which is a horizontal plane, is displaced upward in the drawing so that the dimension from the base body portion 41 is gradually increased, the extra thickness 31 moves toward the center side at the end portion of the rough material 30 as the machining progresses. To be made. In that case, since the vertical surface 45 extending upward from the top of the protrusion 42 defines the shape of the end surface of the rough material 30, the end surface 1 perpendicular to the central axis of the rough material 30 is defined at this portion.
1 is formed.

The interval between the new left and right end faces 11 thus generated is defined by the vertical surface 45 of the rolling die 40.
It is the same as the distance W1 between them, and the axial length W2 of the outer peripheral surface of the rough material 30 is defined by the distance between the intersecting portions of the inclined surface 43 and the base portion 41, that is, the width of the flat surface of the base portion 41. The width of the tapered corner portion of the material 30 in the radial direction is the same as the height H1 of the protrusion 42, and the width of the end surface of the rough material 30 including the tapered corner portion from the outer peripheral surface is a vertical surface. It is the same as the dimension H2 from the base portion 41 of 45.
As a result, the rough material 40 is deformed by the ridges 42, the side surfaces 44, and the vertical surfaces 45 to correct the ends, and the piston pin 10 having the desired shape and size is obtained.

In the case of the processing method using the rolling die 40 shown in FIG. 5, the surplus 31 at the beginning of the processing.
Is generated by cutting it from the rough material 30 in a partially connected state, and the extra thickness 31 is moved to the center side of the shaft end portion. Therefore, the amount of material to be made to flow in the rough material 30 is smaller than that in the method shown in the first embodiment, and as a result, the load required for processing is correspondingly reduced and the service life of the rolling die 40 is reduced. Becomes longer and peeling of the material from the rough material 30 is less likely to occur.

In this way, another example will be described in which the surplus material 31 is first formed in the rough material 30, the taper processing is performed in parallel with this, and the surplus material 31 is moved to a predetermined position. . FIG. 8 shows a pair of rolling dies 5 used for the processing.
0 shows a part of one, and on the left and right sides of the base portion 51, thin plate-like ridges 52 having a gradually increasing height are formed to project. The maximum height of the protrusion 52 is set to be the same as the dimension H1 measured in the radial direction from the outer peripheral surface 12 of the tapered portion 13 of the piston pin 10. The distance between the left and right ridges 52 is gradually widened as the height thereof is increased. That is, the space at the start end portion where the piston pin 1 starts to project from the base body portion 51 is the smallest.
0 is set to be the same as the axial length W2 of the outer peripheral surface 12, and the interval at the highest height is the end surface 1 of the piston pin 10.
It is set to be the same as the interval W1 between the two.

In the above-mentioned embodiment, the outer side surface of the ridge is gradually horizontal, but in this embodiment, the ridge 52 itself is twisted so as to be horizontally horizontal. That is, in the portion of the protrusion 52 on the front side of the maximum height, the height of the top of the protrusion 52 from the base portion 51 is not changed, and the portion of the protrusion 52 on the base side (root portion) is the piston pin. 10 is gradually displaced to the front side in the axial direction, and the protrusion 52 is twisted outward so that the entire protrusion 52 becomes gradually horizontal, which is schematically shown in FIG. Further, the protrusion 52 has a height gradually increasing from the base portion 51 in a state of being parallel to the base portion 51, and the maximum height H2 thereof includes the taper portion 13 of the piston pin 10. It is set to be the same as the dimension H2 from the outer peripheral surface 12 of the end surface 11.

When the end face of the rough material 30 is corrected by the rolling die 50, the rough material is sandwiched between the pair of rolling dies 50, and the rolling dies 50 are linearly moved in the opposite directions in this state. Rolling the rough material 30 by moving it is the same as in each of the above-described embodiments. Rough material 3 in that case
The process of deformation of the 0 end is shown in FIG. As described above, the ridge 52 is configured so as to gradually project from the surface of the base portion 51 and gradually increase in height, so that the rough material 30 rolls relative to the rolling die 50. As a result, the protrusion 52 gradually bites into the end of the rough material 30. The distance between the left and right ridges 52 increases as the height increases, so that the bite position with respect to the rough material 30 moves to the axial end side of the rough material 30. Therefore, rough material 3
The end portion of 0 is deformed into a taper shape. The starting position of the deformation is defined by the minimum distance W2 between the ridges 52, and the end position of the tapered portion is the place where the ridge 52 is the most recessed in the radial direction.
The space between the two is defined by the dimension W1 of the widest part. As a result, the taper portion 13 is formed on the rough material 30 by the portion of the ridge 52 that stands substantially vertically from the base portion 51.
Is formed.

As described above, when the protrusion 52 is inserted into the end of the rough material 30 so as to be cut, the tapered portion 13 is formed and the excess thickness 31 is generated. And ridge 52
As described above, the horizontal direction is changed so as to rotate around the top on the other end side of the base 51, so that the surplus 31
Is pushed by the ridge 52 to change the protruding direction in a direction parallel to the central axis of the rough material 30. Further, since the protrusion 52 is displaced in parallel with the base 51 so that the dimension from the base 51 is enlarged, the surplus 31 parallel to the central axis of the rough material 30 is formed by the protrusion 52. Is moved to the center side of the rough material 30. That is, the extra thickness 31 moves the end of the raw material 30 toward the center in the radial direction, and accordingly, the end face 11 perpendicular to the central axis is formed at the end of the rough material 30.

The spacing between the new left and right end faces 11 thus generated is the same as the spacing W1 between the tips of the projections 52 whose postures are changed in a direction parallel to the base 51, and the projections 52 are also formed. The axial length W2 of the outer peripheral surface of the rough material 30 is defined by the distance W2 between the ridges 52 at the point where the ribs start to project from the base portion 51, that is, the width of the flat surface of the base portion 51. The width of the portion in the radial direction is the same as the maximum height H1 of the protrusion 52, and the width from the outer peripheral surface of the end face of the rough material 30 including the tapered corners is from the base portion 51 of the protrusion 52. It becomes the same as the dimension H2. As a result, the rough material 30 is deformed by the ridges 52 to correct the ends thereof, and the piston pin 1 having the desired shape and size is obtained.
It is set to 0.

In the method using the rolling die 5 shown in FIG. 8 as well, the surplus material 31 is cut off from the rough material 30 so as to be partially connected at the beginning of processing,
The extra thickness 31 is moved toward the center of the shaft end, and at that time, the protrusion 52 does not come into contact with the already processed portion. Therefore, the amount of material to be flowed in the rough material 30 is smaller than that in the method shown in the first embodiment, and as a result,
The load required for processing is reduced accordingly and the rolling die 5
0 has a long useful life, and peeling of the material from the rough material 30 is less likely to occur.

As described above, in the method or rolling die of the present invention, a load is applied to the axial end portion of the rough material 30 to cause the material to flow, thereby correcting the end surface.
Since the compressive load is also applied to the outer peripheral surface of 0, the piston pin 10 having good cylindricity can be obtained, and at the same time, it becomes easy to prevent the dents before the heat treatment of the piston pin due to work hardening by the vanish.

In each of the above-mentioned embodiments, the flat rolling is adopted for the laying, but the present invention is not limited to the above-mentioned embodiments, and the die is formed into a cylindrical shape to be rolled. You may go. Further, the processed product targeted by the present invention is not limited to the Biston pin, and can be widely applied to end face correction of a shaft-shaped member having a general circular cross section.

[0036]

As described above, according to the method of the present invention and the die for carrying out the method, it is possible to obtain the desired end face shape and size by material flow, so that burrs are generated and are accompanied thereby. There is no need for post-processing, so efficient end face straightening can be performed,
Productivity can be improved. Moreover, the product quality can be improved by work hardening of the end faces. Further, in the present invention, since the dimensional accuracy of the product can be improved by the dimensional control in the die, even if the dimensional accuracy of the rough material varies, the dimension can be machined to a desired dimension, and therefore the degree of freedom of the rough material is reduced. Get higher Furthermore, in the method and die of the present invention, since the load is applied to the local portion of the rough material, the molding load is reduced to extend the service life of the molding die, and the relative slip between the rough material and the die is reduced. It is possible to reduce the material separation of the rough material and the defects caused thereby, and it is possible to reduce the cost as a whole.

Particularly, in the method described in claim 2 and the die described in claim 3, since the molding load is mainly applied to the surplus generated by cutting the rough material, the molding load may be low. Since the die does not have to come into contact with the already-processed part, it is possible to obtain a more excellent effect of improving the mold life and improving the accuracy of the product.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a rolling die used in the method of the present invention.

FIG. 2 is a cross-sectional view schematically showing a target product in the embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing a cross-sectional shape of a second ridge in the rolling die.

FIG. 4 is an explanatory view schematically showing a progress state of processing in the first embodiment of the present invention.

FIG. 5 is a perspective view showing a part of a rolling die used in another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining a change in shape of a ridge in the rolling die.

FIG. 7 is an explanatory view schematically showing a progressing state of processing using the rolling die.

FIG. 8 is a perspective view showing a part of a rolling die used in still another embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view for explaining a shape change of a protrusion in the rolling die.

FIG. 10 is an explanatory view schematically showing a progressing state of processing using the rolling die.

FIG. 11 is a view for explaining a conventional method of straightening an end face by applying a press load in the axial direction.

FIG. 12 is a diagram for explaining a state in which burrs are generated by a conventional method.

FIG. 13 is a partial view schematically showing a fracture surface that occurs when burrs are removed by press working.

[Explanation of symbols]

 10 Piston Pin 11 End Surface 12 Outer Surface 13 Tapered Part 20, 40, 50 Rolling Dies 22, 42, 52 Ridge 30 Rough Material 31 Surplus

Claims (3)

[Claims] 1. A shaft-shaped rough material having a circular cross section is sandwiched between a pair of rolling dies to be rolled, whereby a load is applied to the end portion of the shaft-shaped rough material from the outside in the radial direction. Causing the material to flow, and moving the surplus generated by the flow of the material to the central portion at the end of the rough material so as to project in the axial direction from the surplus projected in the axial direction. An end face correcting method for a shaft-shaped member having a circular cross section, characterized in that the end face generated on the outer peripheral side is used as a finished product surface. 2. The excess thickness is generated by applying a cutting load to the end of the shaft-like rough material with a narrow width along a plane perpendicular to the central axis, and then applying the load to the excess thickness. The method of correcting an end surface of a shaft-shaped member having a circular cross section according to claim 1, wherein the surplus is moved to a central portion of an end portion of the rough material so as to project in the axial direction. 3. A shaft-shaped rough material having a circular cross section is sandwiched and moved in a direction in which the rough material rolls, thereby causing a partial plastic deformation at the ends of the rough material to have a predetermined shape and size. In the rolling die formed in, a thin plate-shaped ridge protruding toward the rough material and having a gradually increasing projection height is formed at a position corresponding to the end of the rough material in a state where the rough material is sandwiched. In addition, a part of the ridge having a high protrusion height on the base side is gradually displaced toward the front side in the axial direction of the rough material so that the ridge becomes gradually parallel to the central axis of the rough material. An end-face straightening rolling die for a shaft-shaped member having a circular cross section, which is formed into a twisted shape.