JP3835941B2 - Manufacturing method of coarse gear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionCoarse gearIn particular, the present invention relates to a technique for manufacturing mainly forging.
[0002]
[Prior art]
Manufacturing a helical gear by a process mainly composed of forging is described in, for example, Japanese Patent Application Laid-Open No. 8-206772, but it is necessary to forcibly rotate the punch along the tooth trace of the helical gear. Therefore, there are many movable parts and the structure becomes complicated. Further, since the tooth portion of the helical gear is forcibly formed by forging, the material flow is not sufficiently performed, and there is a possibility that sagging or chipping occurs. In addition, gear forming by hermetic forging is performed, but depending on the tooth shape, high pressure must be applied to fill the material sufficiently, and there is a problem with the durability and life of the mold It was.
[0003]
On the other hand, because of the good material yield that is the merit of forging and the good machining accuracy that is the merit of cutting, the cylindrical material pre-formed by forging is cut to form teeth. Can be considered. In this case, as a method of manufacturing a cylindrical material by forging, for example, as shown in FIG. 11, first, in (a), a rough material 200 having a predetermined length is cut out from a cylindrical round bar, and (b ) Is forged from the axial direction so as to have an outer diameter that is substantially equal to the outer diameter of the target cylindrical part 202 (see (d)). Further, in (c), a bottomed hole 206 having a diameter substantially equal to the through-hole 204 to be formed is formed by extrusion forging, and in (d), the bottom portion 208 of the bottomed hole 206 is punched by a punching punch. A cylindrical part 202 is obtained. 11 is a center line, and the left half is a cross-sectional view.
[0004]
[Problems to be solved by the invention]
However, in such a manufacturing method of the cylindrical part 202, the surface accuracy of the end surface 210 in the axial direction (perpendicularity, flatness, etc. with respect to the center line) cannot be sufficiently obtained, and then the tooth surface is used with the end surface 210 as a reference surface. There has been a problem that processing accuracy is impaired when cutting or the like is performed. That is, in the extrusion forging of (c), when the punch is pushed into the bottomed hole 206, the material of the portion flows in the axial direction, but sufficient surface accuracy is obtained such that it is not necessarily uniform around the center line. It is not possible. After punching of (d), it is conceivable to increase the accuracy of the end surface 210 by compressing in the axial direction while restraining the outer peripheral surface and the inner peripheral surface. Therefore, it is difficult to obtain high surface accuracy.
[0006]
  The present invention has been made against the background of the above circumstances, and the object of the present invention is high squareness and flatness of the axial end surface.Coarse gearIs to be able to manufacture mainly forging.
[0007]
[Means for Solving the Problems]
  In order to achieve this object, the first invention provides:(a) A cylindrical shape having an outer peripheral surface and an inner peripheral surface, and a pair of end surfaces connecting the outer peripheral surface and the inner peripheral surface in the radial direction at both ends in the axial direction, and (b) The tooth of the external tooth or the internal gear is formed by cutting on the outer peripheral surface or the inner peripheral surface in the subsequent process, (c) Of the pair of end facesAt least oneOf the cutting processMade of metal used as reference planeCoarse gearA manufacturing method of(d)A convex portion protruding in the axial direction on the end surface or a portion to be the end surfaceBy forgingForm and thenOf the outer peripheral surface and the inner peripheral surfaceWhile preventing deformation, by compressing from the axial direction so that a gap remains between the end surface portion other than the convex portion and the mold, the accuracy is improved so that the tip surface of the convex portion can be used as the reference surface. It is characterized by doing.
[0008]
  The second invention is(a)A through hole with a circular cross section in the centerAnd having a cylindrical shape including an outer peripheral surface and an inner peripheral surface, and a pair of end surfaces connecting the outer peripheral surface and the inner peripheral surface in the radial direction at both ends in the axial direction, (b) The tooth of the external tooth or the internal gear is formed by cutting on the outer peripheral surface or the inner peripheral surface in the subsequent process, (c) At least one of the pair of end surfaces is used as a reference surface for the cutting process.MetalCoarse gearA method of manufacturing(d)By forging a predetermined rough material, the outer diameter isCoarse gearIs approximately equal to the outer diameter and the axial length isCoarse gearA cylindrical convex portion projecting in the axial direction is formed on a portion of at least one end surface in the axial direction and outside the through hole. A first intermediate product manufacturing step for manufacturing a first intermediate product provided substantially concentrically with the cylindrical center line;(e)By constraining the outer peripheral surface of the first intermediate product and forming a bottomed hole having a diameter substantially equal to the through hole at the center of the first intermediate product by forging, the axial length isCoarse gearA second intermediate product manufacturing step of manufacturing a second intermediate product approximately equal to the axial length of(f)Punching out the bottom of the bottomed hole of the second intermediate product to form the through hole, and a third intermediate product manufacturing step for manufacturing a cylindrical third intermediate product;(g)The third intermediate product is axially arranged so that a gap remains between the end surface portion other than the annular convex portion and the mold while preventing deformation of the outer peripheral surface and the inner peripheral surface of the third intermediate product. The tip of the convex partTo be used as the reference planeAnd a surface finishing step for obtaining accuracy.
[0011]
【The invention's effect】
  Of the first inventionCoarse gearIn the manufacturing method, at least one end face in the axial direction is, When cutting the teeth of internal gear or external gear in the later processWhen used as a reference surface, a convex part protruding in the axial direction on the end surface or the portion that becomes the end surfaceBy forgingForm and thenOf the outer peripheral surface and inner peripheral surfaceWhile preventing deformation, by compressing from the axial direction so that a gap remains between the end surface portion other than the convex portion and the mold, the tip end surface of the convex portion is made accurate so that it can be used as a reference surface. It is like that. That is, since the portion other than the tip surface of the convex portion of the end surface does not necessarily require accuracy, it is possible to provide a gap between the mold and the metal flow receiving tray accompanying compression, and restrain the surface other than the end surface. Regardless of this, the tip surface of the projection can be reliably plastically deformed by compression, and high surface accuracy (such as perpendicularity to the axis and flatness) can be obtained. As a result, it is possible to perform post-processing gear cutting and the like with high accuracy using the tip surface of the convex portion as a reference surface.
[0012]
  The second invention is, RealQualitatively corresponding to one embodiment of the first invention, the tip surface of the convex portion is formed with high surface accuracy. Since the convex portion is formed in a cylindrical shape, the mold structure is easily configured as compared with the case where the convex portion is formed after the through hole is formed. In the second intermediate product manufacturing process, the metal in the bottomed hole portion is caused to flow in the axial direction. Therefore, when the bottomed hole is formed from the end surface side where the convex portion is provided, the end surface shape including the convex portion is deformed. However, since the outer diameter of the first intermediate product is maintained, the end face on the outer peripheral side from the bottomed hole is merely pushed in the axial direction and is not greatly deformed so that the convex portion is not understood. In the surface finishing step, the tip surface of the convex portion is reliably plastically deformed over the entire circumference, and the accuracy is obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention relates to a coarse gear such as a helical gear.MaterialSuitable for manufacturingThe
[0016]
  The tip surface of the convex portion provided on the end surface is generally a flat surface perpendicular to the center line, but may be inclined by a predetermined angle from a plane perpendicular to the center line.SuitableIt is set appropriately.
[0017]
  In the second invention, the convex portion is provided before the through hole is formed, and the accuracy of the tip end surface of the convex portion is determined after the through hole is formed. Forging after forming (such as coining))Therefore, while providing a convex part, after that, a convex part may be compressed and the precision of a front end surface may be made | formed. In the first invention, it is not always necessary to provide an annular convex portion.Absent.
[0018]
  Although only one of the end surfaces may be provided as the convex portion, it is desirable to provide the both end surfaces for ease of subsequent handling. The convex part is in the product state (cylindricalCoarse gear), A part of the end face, that is, the inner peripheral side of the annular end face, the outer peripheral side, or an intermediate position thereof. It is desirable to provide it on the side part.Yes.
[0019]
  In the first intermediate product manufacturing process, for example, (a) the outer diameter dimension isCoarse gearA cutting step of cutting a cylindrical coarse material smaller than the outer diameter of the round bar material, and (b) the outer diameter dimension isCoarse gearIs approximately equal to the outer diameter and the axial length isCoarse gearAn upsetting forging step of upsetting and forging the columnar rough material in the axial direction so as to be shorter than the axial length of, and (c) an indentation forging step of forming a convex portion on the end face by an indentation process or the like thereafter. It is desirable to have. That is, the outer diameter dimension isCoarse gearIs approximately equal to the outer diameter and the axial length isCoarse gearA cylindrical rough material having a columnar shape shorter than the axial length of the material is cut out from a round bar material, and a convex portion is formed on the end surface of the cylindrical rough material by forging (such as coining). However, it is not preferable because there is distortion on the cut surface and a convex portion is provided on the cut surface from which the metal structure (metal flow) is cut. A round bar is generally used for forging because the metal flow is generally aligned in the axial direction.
[0020]
  The bottomed hole provided in the first intermediate product in the second intermediate product manufacturing process is preferably provided from both end surfaces of the first intermediate product, but it is not necessarily one of the end surfaces (the end surface provided with the convex portion). It is also possible to form a bottomed hole only fromYes.
[0021]
  When compressing the tip of the convex part by compression forging etc. to obtain accuracy,Coarse gearIn order to prevent deformation of the outer peripheral surface and inner peripheral surface, it is desirable to constrain with a restraining die or the like. However, when the amount of compressive deformation of the convex portion is small, the convex formation position is intermediate between the inner and outer peripheral surfaces of the end surface. If the outer peripheral surface or the inner peripheral surface is not likely to be deformed by plastic deformation due to compression of the convex portion, such as in the case of a position, it is not always necessary to constrain those surfaces. In the first invention and the second invention, “while preventing deformation” means that when deformation is caused by compression forging, the deformation is restrained by a restraining die or the like, but when there is no fear of deformation during compression forging. This means that it is not always necessary to provide special restraining means, and it is only necessary to provide restraining means as necessary so as not to deform.
[0023]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a procedure for manufacturing a cylindrical part 10 according to the method of the present invention. The cylindrical part 10 is a metal cylindrical part having a through-hole 12 having a circular cross section at the center, and annular ends projecting in the axial direction toward the inner peripheral side on both end faces 14 and 16 respectively. Shaped convex portions 14a and 16a are provided, and tip surfaces of the convex portions 14a and 16a are flat surfaces perpendicular to the center line. This cylindrical part 10 is a coarse material of an external gear such as a helical gear, and teeth are formed by cutting on the outer peripheral side of the convex portions 14a and 16a in the subsequent process. 14a or 16a is used as a reference plane. All the dashed-dotted lines in each of the drawings (a) to (f) in FIG. 1 represent the center line, and the left half of the center line is a cross-sectional view.
[0024]
FIG. 1A shows a cutting step, in which a round bar having an outer diameter smaller than the outer diameter of the target cylindrical part 10 is cut to a predetermined length to prepare a cylindrical coarse member 20. The round bar material is obtained by drawing or the like, and the metal flow is aligned in the axial direction, and the columnar coarse material 20 is the same, but strain at the time of cutting remains on both end faces 22 and 24. . In the present embodiment, cutting is performed by press shearing, and there is distortion due to shear.
[0025]
FIG. 1B shows a swaging forging step, in which the columnar coarse material 20 is swept in the axial direction, so that the outer diameter is substantially equal to the outer diameter of the cylindrical component 10 and the axial length is the same. A substantially cylindrical intermediate product 30 shorter than the axial length of the cylindrical part 10 is manufactured. The forging device 32 shown in FIGS. 2 and 3 is an example of a forging device that performs upset forging shown in FIG. 1B. FIG. 2 shows that the columnar coarse material 20 is substantially vertical on the lower die 34 by a conveying device (not shown). Is positioned with the presser punch 36. The presser punch 36 is urged downward by a spring 38. The cylindrical coarse member 20 is positioned and held on the lower die 34 according to the urging force of the spring 38, while the upper die 40 is lowered. When the sliding member 44 reaches the upper moving end by being relatively pushed into the accommodation hole 42, the lower end surface of the presser punch 36 is substantially matched with the forming surface (lower end surface) of the forming punch 46. Then, when the upper die 40 is further lowered in this state, the cylindrical coarse material 20 is disposed on the presser punch 36, the forming punch 46, the lower die 34, and the lower die 34 as shown in FIG. In the substantially sealed space surrounded by the ring die 48, the intermediate product 30 is compressed in the axial direction. The inner diameter of the ring die 48 is substantially equal to the outer diameter of the cylindrical part 10. A slight gap exists between the molding punch 46 and the ring die 48 at the bottom dead center, and a knockout pin 50 is disposed at the center of the lower die 34.
[0026]
By performing upset forging in this manner, distortion generated during cutting is corrected, and the weight balance around the axis is improved. In addition, the lower surface of the inner wall surface of the ring die 48 is provided with an inclined surface (tapered surface) so that the diameter dimension gradually decreases, and the outer peripheral surface 54 on the one end 52 side of the intermediate product 30 is an inclined surface. The taper surface has a slightly smaller diameter as the end portion 52 is approached.
[0027]
FIG. 1C shows a coining forging step, in which both end surfaces of the intermediate product 30 are subjected to coining, so that a part of the portion outside the through hole 12, specifically the convex portion 14 a. 16a, an intermediate product 60 is produced in which annular-shaped convex portions 56, 58 projecting in the axial direction are provided substantially concentrically with the center line on the inner peripheral side portion that continues to the through hole 12 so as to correspond to 16a. . The convex portions 56 and 58 have substantially the same shape with the same width dimension and protruding dimension, and the protruding dimension is about 0.55 mm. The forging device 62 shown in FIGS. 4 and 5 is an example of a forging device that performs the coining forging shown in FIG. 1 (c). FIG. 4 shows that the intermediate product 30 is disposed in the die 64 by a conveying device (not shown), FIG. 5 shows a state in which the forging is performed by the die 64 and the punch 68 and the intermediate product 60 having the convex portions 56 and 58 is formed. The intermediate product 30 is arranged in an upside down posture so that the end 52 side, that is, the side on which the tapered outer peripheral surface 54 is formed, is upward, and when the intermediate product 30 is pressed by the punch 68 as shown in FIG. The coarse material is prevented from overflowing from between the opening of the die 64 and the punch 68.
[0028]
The presser punch 66 is urged downward by a spring 70, and positions and fixes the intermediate product 30 according to the urging force of the spring 70, while the upper die 72 is lowered and is relatively moved into the accommodation hole 74. When the sliding member 76 reaches the upper moving end, the lower end surface of the presser punch 66 is made substantially coincident with the lower end surface of the first ring punch 78. The presser punch 66 has an outer diameter dimension substantially equal to the inner diameter of the through-hole 12, that is, the inner diameter of the convex part 56, and the inner diameter dimension of the first ring punch 78 is substantially equal to the outer diameter dimension of the convex part 56. The second ring punch 80 is disposed so that the lower end surface is recessed by the protruding dimension of the convex portion 56. The presser punch 66, the first ring punch 78, and the second ring punch 80 constitute a punch 68.
[0029]
The die 64 includes a knockout pin 82, a first ring die 84, a second ring die 86, and an outer peripheral surface constraining die 88. The knockout pin 82 has an outer diameter dimension substantially equal to the inner diameter of the through hole 12, that is, the inner diameter of the convex portion 58, and the inner diameter dimension of the first ring die 84 is substantially equal to the outer diameter dimension of the convex portion 58. The second ring die 86 is disposed such that the upper end surface is recessed by the protruding dimension of the convex portion 58. The outer peripheral surface constraining die 88 is disposed on the first ring die 84, and the inner diameter thereof is substantially equal to the outer diameter of the cylindrical component 10, that is, the outer diameter of the intermediate product 30, and the intermediate product. Indentation forging is performed in a state in which 30 is positioned concentrically and the outer peripheral surface is constrained.
[0030]
  In this example, the cutting process shown in FIG. 1 (a), the upset forging process shown in FIG. 1 (b), and the coining forging process shown in FIG.MysteriousThe intermediate product 60 corresponds to a first intermediate product manufacturing process, and the intermediate product 60 corresponds to a first intermediate product.
[0031]
  FIG. 1 (d) shows an extrusion forging process, in which the outer peripheral surface 60f of the intermediate product 60 is constrained, and the center of both end surfaces, that is, the inner portions of the convex portions 56 and 58 have a bottomed diameter of the same diameter as the through hole 12. By forming the holes 90 and 92, an intermediate product 94 having an axial length substantially equal to the axial length of the cylindrical part 10 is manufactured. A forging device 96 in FIG. 6 is an example of a forging device that performs the extrusion forging in FIG. 1 (d), and an intermediate product 60 that has bottomed holes 90, 92 that is subjected to extrusion forging by the punch 98 and the die 100 to the intermediate product 60. 94. The extrusion forging process in Fig. 1 (d)MysteriousSecond intermediate product manufacturerAboutThe intermediate product 94 corresponds to a second intermediate product.
[0032]
The punch 98 includes a center punch 102 having an outer diameter substantially equal to that of the through hole 12 and a ring punch 104 disposed on the outer peripheral side thereof. A recess corresponding to the convex portion 56 is formed on the inner peripheral side of the ring punch 104. Is provided so that the convex portion 56 of the intermediate product 60 is maintained in a substantially unchanged shape. The center punch 102 protrudes larger than the protruding dimension of the convex portion 56 in the intermediate product 60, thereby forming a bottomed hole 90. The die 100 includes a knockout pin 106 having an outer diameter equal to that of the through hole 12, a ring die 108 having a width dimension equal to the width dimension of the convex portion 58, and an outer diameter of the cylindrical part 10. The outer peripheral surface constraining die 110 is equal in size to the outer diameter of the intermediate product 60. The knockout pin 106 protrudes upward from the upper end surface of the ring die 108 sufficiently larger than the protruding dimension of the convex portion 58, and the punch 98 is lowered and the intermediate product 60 is pressed against the knockout pin 106. The knockout pin 106 bites into the intermediate product 60 and the portion of the coarse material is caused to flow into the annular space between the knockout pin 106 and the outer peripheral surface restraining die 110, thereby forming a bottomed hole 92 deeper than the bottomed hole 90. In addition, an intermediate product 94 having an axial length substantially equal to the axial length of the cylindrical part 10 is obtained. Although the rough material of the bottomed hole 90 portion is caused to flow downward in the axial direction, the outer diameter size of the intermediate product 60 is maintained by the outer peripheral surface constraining die 110, and therefore the convex portion 58 and the end surface outside it are simply shafts. Only by being pushed downward in the direction, the shape of the convex portion 58 when it is the intermediate product 60 is maintained as it is. Further, the intermediate product 60 is positioned and held concentrically by being inserted into the outer peripheral surface restraining die 110. A slight gap remains between the lower end portion of the molded intermediate product 94, strictly speaking, the convex portion 58 and the upper end surface of the ring die 108.
[0033]
  FIG. 1 (e) shows a punching process, in which a punching punch is inserted into one bottomed hole 92 of the intermediate product 94, thereby punching out the bottom 112 existing between the bottomed holes 90 and 92, and the through hole. 12 is formed, and a cylindrical intermediate product 114 is manufactured. The press machine 116 in FIG. 7 is an example of a press machine that performs the punching process (piercing process) in FIG. 1 (e), and the bottom 112 of the intermediate product 94 is punched out by a cylindrical presser punch 118 and a cylindrical punching punch 120. The intermediate product 114 having the through hole 12 is formed. The punching process in Fig. 1 (e)MysteriousThird intermediate product manufacturerAboutThe intermediate product 114 corresponds to a third intermediate product.
[0034]
The lower end surface of the presser punch 118 has an outer diameter that is the same as or slightly smaller than the outer diameter of the intermediate product 94, and an inner diameter that is the same as or slightly larger than the inner diameter of the convex portion 56, and corresponds to the convex portion 56. A concave portion is provided to maintain the shape of the convex portion 56. The upper end surface of the punching punch 120 is slightly smaller in outer diameter than the inner diameter of the bottomed hole 92, and a shearing blade is provided on the outer peripheral edge thereof, and the intermediate product 94 is pressed downward by the presser punch 118. Accordingly, the punching punch 120 is relatively inserted into the bottomed hole 92, and the bottom 112 is punched upward by a shearing blade. A positioning die 122 having an inner diameter approximately equal to the outer diameter of the intermediate product 94 is disposed concentrically around the punching punch 120 so that the intermediate product 94 is positioned concentrically. In addition, the punched bottom portion 112 is pushed upward in the cylinder of the presser punch 118 as the new bottom portion 112 is punched upward as the punching process is repeated, and discharged from the discharge hole 124 to the outside. Is done.
[0035]
Here, on the inner peripheral surface of the through hole 12 of the intermediate product 114, a minute step 126 remains in the portion where the bottom 112 is present. FIG. 9A is a diagram showing the metal flow F in a cross section of the intermediate product 114 in a simplified manner. The metal flow F is compressed at the bottom 112 portion and is broken by punching the bottom 112 by the punching process. At the same time, the broken portion of the metal flow F remains in the through hole 12 as a burr and forms a step 126. FIG. 9B is an enlarged view of the vicinity of the step (burr) 126. When the bottom 112 is punched upward by the punching punch 120, the metal flow F is shredded and remains in an upwardly inclined state. .
[0036]
  FIG. 1 (f) is a surface finishing step, in which a burnishing tool is pushed into the through hole 12 from the side opposite to the insertion side of the punching punch 120, and the inner peripheral surface of the through hole 12 is burnished. The intermediate product 114 is compressed from the axial direction while restraining the outer peripheral surface and the inner peripheral surface of the product 114, and the tip surfaces of the convex portions 56 and 58 are brought into a predetermined shape. The forging device 130 of FIG. 8 is an example of a forging device that performs the surface finishing of FIG. 1 (f), and an intermediate product 114 that is disposed upside down in the die 132 so that the convex portion 56 side is directed downward, By being pressed downward by the cylindrical presser punch 134, the columnar burnishing tool 136 is pushed into the through hole 12 from the convex portion 56 side, and the inner peripheral surface of the through hole 12 is burnished. By compressing from the axial direction while restraining the outer peripheral surface with the outer peripheral surface restraining die 138 while constraining the inner peripheral surface with the burnishing tool 136, the accuracy of the tip surfaces of the convex portions 56 and 58 on both end surfaces is increased once. The target cylindrical part 10 is obtained in the pressing process. The surface finishing process in Fig. 1 (f)MysteriousIt is a surface finishing process.
[0037]
The lower end surface of the press punch 134 has a depth that is substantially the same as the outer diameter of the intermediate product 114, the inner diameter is substantially the same as the inner diameter of the bottomed hole 12, and is slightly smaller than the protruding dimension of the convex portion 58. The concave portion is provided on the inner peripheral side corresponding to the convex portion 58, and the tip of the convex portion 58 is plastically deformed by pressing the intermediate product 114 downward and compressing, and the lower end surface of the presser punch 134. The convex portion 14a having a shape corresponding to is forged. The projecting dimension of the convex portion 14 a is about 0.50 mm, and is compressed by about 0.05 mm compared to the convex portion 58. The burnishing tool 136 has an outer diameter dimension substantially equal to the inner diameter of the through hole 12 and burnishes the inner peripheral surface by being pushed into the through hole 12, and from the axial direction while being pushed into the through hole 12. When compression forging is performed, the inner peripheral surface of the intermediate product 114 is restrained. Around the burnishing tool 136, a first ring die 140 having an inner diameter dimension substantially equal to the outer diameter dimension of the convex portion 56 is disposed, and the upper end surface of the first ring die 140 is a projection dimension of the convex portion 56 therebetween. The second ring die 142 is disposed so as to be lower than the first ring die 140 by a smaller predetermined dimension. When the intermediate product 114 is pressed downward by the presser punch 134, the tip of the convex portion 56 is second. The convex portion 16 a having a tip surface corresponding to the tip surface shape of the second ring die 142 is forged by being brought into contact with the ring die 142 and plastically deformed. The outer peripheral surface restraining die 138 is disposed on the first ring die 140, and the inner diameter thereof is equal to the outer diameter of the cylindrical part 10, that is, the outer diameter of the intermediate article 114. And forging are performed in a state where the outer peripheral surface is constrained.
[0038]
Here, the burnishing tool 136 is pushed into the through-hole 12 from the upper side to the lower side in FIG. 9B on the side opposite to the insertion side of the punching punch 120, that is, the end side having the convex portion 56. Therefore, the burrs are pressed back against the fracture portion of the inner peripheral surface, that is, the cut portion of the bottom portion 112 broken by the punching punch 120, and the step 126 is satisfactorily eliminated and high surface accuracy (surface roughness) is obtained. can get. That is, when the burnishing tool 136 is pushed in from the same direction as the punching punch 120 (the lower side in FIG. 9B), the burr is further extended upward, and the through hole 12 (strictly, the bottomed hole 90 portion) Just by being pressed against the inner peripheral surface, the portion is built up, and high surface accuracy is not necessarily obtained. Since the burr is formed by cutting the metal flow F by the punching punch 120, the burr is completely removed even if the burnishing tool 136 is moved in the same direction as the pulling direction, that is, the insertion direction of the punching punch 120. No, it is crimped to the inner peripheral surface.
[0039]
On the other hand, in a state where the intermediate product 114 is compression-forged between the press punch 134 and the second ring die 142, that is, in a state where it is formed into the cylindrical part 10, the cylindrical coarse material 10 and the first ring die 140 As shown in FIG. 10, a slight gap remains between the upper end surface and the tip of the convex portion 56 is reliably plastic over the entire circumference regardless of the restraint of the outer peripheral surface and the inner peripheral surface. The second ring die 142 is deformed and formed into a surface shape corresponding to the upper end surface of the second ring die 142 with high accuracy. Accordingly, the tip surfaces of the convex portions 14a and 16a of the both end faces 14 and 16 of the cylindrical part 10 are both made high with high surface accuracy by compression forging in the surface finishing process of FIG. 1 (f). Molded with high accuracy on a flat surface perpendicular to the center line. The recesses on the upper end surface of the second ring die 142 and the lower end surface of the presser punch 134 are both flat surfaces perpendicular to the center line. In addition, since the gap exists in this way, the forging pressure can be reduced and an excellent die life can be obtained. The projecting dimension of the convex part 16a is also about 0.50 mm, which is compressed by about 0.05 mm as compared with the convex part 56. This compressed dimension is caused by variations in the projecting dimension of the entire circumference of the convex parts 56 and 58, etc. Considering this, it is determined as appropriate so that compression forging is performed over the entire circumference. In addition, a gap may be formed between the outer peripheral side portion (the portion other than the concave portion) of the lower end surface of the presser punch 134 and the cylindrical component 10.
[0040]
As described above, the cylindrical part 10 of this embodiment is manufactured by a process mainly composed of forging processes ((b), (c), (d), (f) in FIG. 1), and therefore, the material yield is excellent. In addition, since the metal flow F is connected from both ends to the outer peripheral portion, excellent mechanical characteristics can be obtained particularly on the outer peripheral portion side.
[0041]
Further, at the stage of the intermediate product 60, convex portions 56 and 58 protruding in the axial direction are formed on both end faces by coining forging (FIG. 1 (c)), and the surface finishing step (FIG. 1 (f)) is performed after the through holes 12 are formed. ) In the axial direction and the tip portions of the convex portions 56 and 58 are plastically deformed to increase the accuracy, so that the surface accuracy of the tip surfaces of the convex portions 14a and 16a (the perpendicularity to the axis) The flatness of the projections 14a and 16a can be used as a reference surface, and subsequent gear cutting or the like can be performed with high accuracy. In particular, since the convex portions 56 and 58 are formed in a cylindrical shape, the mold structure is easily configured as compared with the case where the convex portions 56 and 58 are formed after the through hole 12 is formed.
[0042]
Further, after forming the bottomed holes 90 and 92 in the extrusion forging process (FIG. 1 (d)), the bottoms 112 of the bottomed holes 90 and 92 are punched out by the punch 120 to form the through holes 12 (FIG. 1). (e)) After that, the burnishing tool 136 is pushed in from the side opposite to the insertion side of the punching punch 120 to burnish the inner peripheral surface of the through hole 12 (FIG. 1 (f)). The burrs formed when punching at 120 are crushed by burnishing, and high surface accuracy (surface roughness) is obtained. For this reason, it is possible to use the cylindrical part 10 as it is as a gear coarse material without requiring a finishing process such as a cutting process.
[0043]
As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a manufacturing process when manufacturing a cylindrical part according to the method of the present invention.
FIG. 2 is a cross-sectional view showing an example of a forging device used in the upset forging step of FIG. 1 (b), in which a workpiece is positioned.
FIG. 3 is a state in which upsetting forging has been performed on a workpiece by the forging device of FIG. 2;
FIG. 4 is a cross-sectional view showing an example of a forging device used in the coining forging step of FIG. 1 (c), in which a workpiece is positioned.
FIG. 5 is a state in which coin forging has been performed on a workpiece by the forging device of FIG. 4;
6 is a cross-sectional view showing an example of a forging device used in the extrusion forging step of FIG. 1 (d), and shows a state in which extrusion forging has been performed on a workpiece.
7 is a cross-sectional view showing an example of a press machine used in the punching process of FIG. 1 (e), in which a workpiece has been punched.
FIG. 8 is a cross-sectional view showing an example of a forging device used in the surface finishing process of FIG. 1 (f), in which a workpiece is burnished and compression forged.
FIG. 9 is a view for explaining a metal flow F of an intermediate product obtained in the punching process of FIG. 1 (e) and burrs generated by the punching.
FIG. 10 is a cross-sectional view for explaining a gap generated during molding (bottom dead center) of the forging device of FIG.
FIG. 11 is a diagram for explaining a comparative example of a manufacturing process when manufacturing a cylindrical part by processing mainly including forging.
[Explanation of symbols]
  10: Cylindrical parts(Coarse gear)
  12: Through hole
  14a, 16a: convex part
  56, 58: convex portion
  60: Intermediate product (first intermediate product)
  90, 92: Bottomed hole
  94: Intermediate product (second intermediate product)
  112: bottom
  114: Intermediate product (third intermediate product)
  120: punching punch

Claims (2)

The outer peripheral surface and the inner peripheral surface have a cylindrical shape with a pair of end surfaces that connect the outer peripheral surface and the inner peripheral surface in the radial direction at both ends in the axial direction. The tooth of the external gear or the internal gear is formed by cutting on the surface or the inner peripheral surface, and at least one of the pair of end surfaces is a metal gear coarse material used as a reference surface for the cutting A manufacturing method comprising:
A convex portion protruding in the axial direction is formed on the end surface or a portion to be the end surface by forging , and thereafter, an end surface portion other than the convex portion and a molding die are prevented while preventing deformation of the outer peripheral surface and the inner peripheral surface. A method for producing a coarse gear material , comprising: compressing from the axial direction so as to leave a gap between the two, so that the tip end surface of the convex portion can be used as the reference surface. Cylindrical shape having a through-hole with a circular cross-section in the center, and an outer peripheral surface and an inner peripheral surface, and a pair of end surfaces that connect the outer peripheral surface and the inner peripheral surface in the radial direction at both ends in the axial direction And at least one of the pair of end faces is a reference for the cutting process, in which a tooth of an external tooth or an internal gear is formed by cutting on the outer peripheral surface or the inner peripheral surface in a later step. A method for producing a metal gear coarse used as a surface ,
By performing forging to a predetermined coarse material, with substantially equal and the axial length outer diameter to the outer diameter of the gear coarse material forms a short cylindrical shape than the axial length of the gear coarse material A ring-shaped convex portion projecting in the axial direction is provided substantially concentrically with the cylindrical center line on a part of at least one end face in the axial direction that is outside the through hole. A first intermediate product manufacturing process for manufacturing one intermediate product;
By constraining the outer peripheral surface of the first intermediate product, a bottomed hole having a diameter substantially equal to the through hole is formed by forging at the center of the first intermediate product, so that the axial length is reduced by the gear coarseness. A second intermediate product manufacturing step for manufacturing a second intermediate product approximately equal to the axial length of the material ;
A third intermediate product manufacturing step of manufacturing the cylindrical third intermediate product by punching out the bottom of the bottomed hole of the second intermediate product to form the through hole;
The third intermediate product is axially arranged so that a gap remains between the end surface portion other than the annular convex portion and the mold while preventing deformation of the outer peripheral surface and the inner peripheral surface of the third intermediate product. by compressing the method for manufacturing a gear coarse material characterized by having a surface finishing step of issuing accuracy to use the distal end surface of the convex portion as the reference plane.

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