CN114589287B

CN114589287B - Method for manufacturing ring gear and pinion gear

Info

Publication number: CN114589287B
Application number: CN202111431095.9A
Authority: CN
Inventors: 毛利浩之
Original assignee: Xiaogu Zhangjiagang Precision Forging Co ltd
Current assignee: Xiaogu Zhangjiagang Precision Forging Co ltd
Priority date: 2020-12-03
Filing date: 2021-11-29
Publication date: 2023-03-28
Anticipated expiration: 2041-11-29
Also published as: JP2022088905A; CN114589287A; JP6927469B1

Abstract

The invention provides a method for manufacturing a ring gear and a pinion, which does not generate scraps by manufacturing other parts by utilizing a central part discarded as scraps in a conventional method for manufacturing a ring gear. The method for manufacturing a ring gear and a pinion gear of the present invention includes: a first step of forming an intermediate member (130) by hot upsetting a columnar material (100), the intermediate member having a disk-shaped portion (130 b) as a preform of a ring gear (142) and a shaft-shaped portion (130 a) as a preform of a pinion gear (147) extending from a center of the disk-shaped portion in one side direction in an axial direction; a second step of pressing a circumferential boundary cross section (separation line (140 c)) between the disk-shaped portion and the shaft-shaped portion by using upper and lower dies to reduce the thickness of the disk-shaped portion and the shaft-shaped portion; and a third step of separating the shaft-like portion from the disc-like portion by pressing the shaft-like portion in one side direction in the axial direction.

Description

Method for manufacturing ring gear and pinion gear

Technical Field

The present invention relates to a manufacturing method for simultaneously manufacturing a ring gear and a pinion gear from 1 raw material by forging.

Background

Conventionally, a ring gear used for a differential gear of an automobile or the like is manufactured by forging. Fig. 4A to 4D are schematic diagrams illustrating a conventional forging-based manufacturing method, and fig. 4A is a first intermediate (preform) 240 of a ring gear formed by forging. The first intermediate member 240 has an annular portion 240a of an outer peripheral portion and a disk-shaped portion 240b of a central portion.

The disk-like portion 240b is cut at a dashed line portion 240c extending in the circumferential direction and discarded as a scrap 246 as shown in fig. 4D. A ring-shaped portion 240a from which the disk-shaped portion 240b is cut out is used as a second intermediate member 241, and finish machining is performed by rolling (rolling) as shown in fig. 4C to form a gear blank 242.

The outer peripheral surface of the gear blank 242 is subjected to cutting processing of a helical gear by hobbing, and then to carburizing and quenching in a surface hardening treatment step. Thus, the intended ring gear for a differential is manufactured. Patent documents 1 to 3 below describe a method for simultaneously manufacturing 2 members (bearing inner and outer races) from 1 material.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. Sho 59-183948

Patent document 2: japanese patent laid-open publication No. 11-244985

Patent document 3: japanese laid-open patent publication No. 2013-240819

Disclosure of Invention

Problems to be solved by the invention

In the conventional method for manufacturing a ring gear, the central disk-shaped portion 240b is discarded as the scrap 246, and therefore, the material is wasted. Accordingly, an object of the present invention is to produce another member by utilizing a central portion discarded as scrap in a conventional method for producing a ring gear, thereby preventing the generation of scrap.

Means for solving the problems

In order to solve the above problems, a method for manufacturing a ring gear and a pinion according to the present invention includes: a first step of forming an intermediate member by hot upsetting a columnar material, the intermediate member having a disk-shaped portion as a preform of a ring gear and a shaft-shaped portion of the preform as a pinion extending from a center of the disk-shaped portion in one side direction in an axial direction; a second step of pressing a circumferential boundary cross section between the disk-shaped portion and the shaft-shaped portion by using upper and lower dies to reduce the thickness of the disk-shaped portion and the shaft-shaped portion; and a third step of separating the shaft-like portion from the disk-like portion by pressing the shaft-like portion in one side direction in the axial direction.

Effects of the invention

The present invention can produce a pinion gear by utilizing a central portion discarded as scrap in a conventional method for producing a ring gear, and thus can prevent the generation of scrap.

Drawings

Fig. 1A is a schematic view showing a method of manufacturing a ring gear and a pinion, and is a sectional view of an intermediate member between the ring gear and the pinion.

Fig. 1B is a schematic view showing a method of manufacturing a ring gear and a pinion, and is a cross-sectional view of a ring gear preform.

Fig. 1C is a schematic view showing a method of manufacturing a ring gear and a pinion gear, and is a product sectional view of the ring gear.

Fig. 1D is a schematic view showing a method of manufacturing a ring gear and a pinion, and is a cross-sectional view of a pinion preform.

Fig. 1E is a schematic view showing a method of manufacturing a ring gear and a pinion gear, and is a product cross-sectional view of the pinion gear.

Fig. 2AA is a sectional view showing deformation of the raw material in the order of steps.

Fig. 2AB is a cross-sectional view showing deformation of the raw material in the order of steps.

Fig. 2AC is a sectional view showing deformation of the raw material in the order of steps.

Fig. 2AD is a cross-sectional view showing deformation of the material in the order of steps.

Fig. 2AE is a cross-sectional view showing deformation of the raw material in the order of steps.

Fig. 2AF is a cross-sectional view showing deformation of the raw material in the order of steps.

Fig. 2AG is a sectional view showing deformation of the raw material in the order of steps.

Fig. 2AH is a sectional view showing deformation of the raw material in the order of steps.

Fig. 2BA is a sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of steps.

Fig. 2BB is a cross-sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of steps.

Fig. 2BC is a sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of steps.

Fig. 2BD is a sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of steps.

Fig. 2BE is a sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of steps.

Fig. 2BF is a sectional view showing an upper die and a lower die used for manufacturing a ring gear and a pinion gear in order of process steps.

Fig. 3 is a diagram showing an influence of a difference in the axial continuous position between the disk-shaped portion and the shaft-shaped portion on the separability, in which (1) shows that the continuous position is the upper side, (2) shows that the continuous position is the center, (3) shows that the continuous position is the lower side, (a) shows before separation, (B) shows the initial separation stage, and (C) shows the intermediate separation stage.

Fig. 4A is a schematic diagram showing a conventional method for manufacturing a ring gear, and is a cross-sectional view of a first intermediate member of the ring gear.

Fig. 4B is a schematic diagram showing a conventional method for manufacturing a ring gear, and is a sectional view of a second intermediate member of the ring gear.

Fig. 4C is a schematic view showing a conventional method for manufacturing a ring gear, and is a product sectional view of the ring gear.

Fig. 4D is a schematic diagram showing a conventional method for manufacturing a ring gear, and is a cross-sectional view of a scrap.

Description of the reference symbols

100: raw materials; 110: forging the product; 120: a first preform; 130: a second preform; 120a, 130a, 140a: a shaft-like portion; 130b, 140b: a disc-shaped portion; 140: a first intermediate member; 140c: a separation line; 140d, 140e: a step surface; 140f: a lower surface; 141. 146: a second intermediate member (preform); 142: a ring gear; 142a: an outer peripheral surface; 142b: a flange; 147: a pinion gear; 240: a first intermediate member; 240a: a cyclic moiety; 240b: a disc-shaped portion; 240c: a dotted line portion; 241: a second middleware; 242: a gear blank; 246: and (4) waste materials.

Detailed Description

Hereinafter, an embodiment of a method for manufacturing a ring gear and a pinion gear according to the present invention will be described with reference to the drawings. Fig. 1A to 1E are schematic views showing a manufacturing method of the present invention, and fig. 1A is a cross-sectional view of a first intermediate material 140 including a disk-shaped portion 140b of a preform as a ring gear and a shaft-shaped portion 140a of a preform as a pinion gear. The ring gear 142 of fig. 1C and the pinion 147 of fig. 1E can be respectively produced from the first intermediate member 140.

That is, the first middleware 140 is separated as shown in fig. 1B and 1D, and the

second middleware

141 and 146 are obtained. The ring gear 142 and the pinion 147 can be produced by machining the second

intermediate members

141 and 146 by rolling (rolling) or hobbing.

(procedure of step)

Fig. 2AA to 2AH are cross-sectional views showing deformation of the raw material in the order of steps along the flow of steps of the production method. Step 0 is a cylindrical raw material 100 before processing. Here, the raw material 100 having an outer diameter of 80mm and an axial length of 160mm was used. The dimensions (mm), ratios (%) and the like used in the description of the present invention are examples, and it is clear that the present invention is not limited to these dimensions, ratios and the like.

This material 100 was compressed in the vertical direction by the first 1-step hot upsetting to form a forged product 110 having an outer diameter of 115mm and an axial length of 105 mm. In this case, the ratio of the axial length to the outer diameter (axial length/outer diameter) was 91%. This ratio may be changed, for example, within a range of 80 to 120% depending on the size of the forged product 110.

Next, the forged product 110 is extrusion molded downward by 2 steps of fig. 2AC to form a first preform 120 having a shaft-like portion 120 a. Next, in step 3 of fig. 2AD, the base end side of the shaft-like portion 130a is pressed in the vertical direction to be expanded in diameter, thereby forming the second preform 130 having the disk-like portion 130 b. In this 3 process, the shaft-like portion 120a of fig. 2AC is brought close to the product shape as the shaft-like portion 130a of fig. 2 AD.

Here, the reason why the disk-shaped portion 130b is molded after the shaft-shaped portion 120a is molded is that if the shaft-shaped portion is molded reversely, the material volume of the shaft center portion is insufficient. If the material volume of the axial core portion is insufficient, the material may not be filled up to the tip end portion of the shaft-like portion 120 a.

However, in the case where the outer diameter ratio of the disk-shaped portion 130b of the second preform 130 is small, and the axial length of the shaft-shaped portion 120a is relatively short, the shaft-shaped

portions

120a and 130a may be molded after the disk-shaped portion 130b is molded. This is because, even if the molding order is reversed in this manner, the material volume of the shaft center portion is not insufficient, and therefore, the material can be filled up to the tip end portion of the shaft-like portion 120 a.

In the step 4 of fig. 2AE, the axial portion 130a and the disk-shaped portion 130b of the second preform 130 of fig. 2AD are brought closer to the product shape, and the circumferential boundary cross section between the axial portion 130a and the disk-shaped portion 130b is thinned. That is, in the shape of the second preform 130 of fig. 2AD, the circumferential boundary cross section between the shaft-shaped portion 130a and the disc-shaped portion 130b is too thick, and thus it is difficult to separate the two by 1 separation process.

Therefore, in the manufacturing method of the present invention, the circumferential boundary cross section of the shaft-shaped portion 130a and the disc-shaped portion 130b of the second preform 130 of fig. 2AD is thinned by the 4-step of fig. 2AE, and then both are separated. Specifically, concentric annular stepped

surfaces

140d and 140e having different heights are formed on the upper surface of the disk-shaped portion 130b in fig. 2 AD.

Sloping downward from the higher step surface 140d to the lower step surface 140e. On the other hand, the substantially horizontal lower surface 140f of the disk-shaped portion 140b is connected at substantially right angles to the outer diameter surface of the shaft-shaped portion 140 a.

Therefore, by pressing the shaft-like portion 140a downward in the axial direction, the shaft-like portion 140a is separated from the disk-like portion 140b along the separation line 140c extending on the outer diameter surface of the shaft-like portion 140a, with the downward inclined lower end portion as a starting point. The lower surface 140f on the opposite side of the higher stepped surface 140d is also a step required for hot rolling in the subsequent step.

The separated shaft-like portion 140a and disk-like portion 140b are shown in fig. 2 AF. The disk-like portion 140b is the final preform (second intermediate piece 141) of the ring gear. The preform 141 had an outer diameter of 158mm and an axial length (height H) of 44mm.

In addition, the shaft-like portion 140a is a final preform (second intermediate member 146) of the pinion. The preform 146 had an outer diameter of 67mm and an axial length (height H) of 121mm.

Finally, the

preforms

141 and 146 are machined in different operations, respectively, whereby the products of fig. 2AG and fig. 2AH are obtained. That is, after the preform 141 is rolled (rolled) into a shape having the outer peripheral surface 142a and the flange 142b, the ring gear 142 of fig. 2AG is obtained by roll-cutting the outer peripheral surface 142a as the first gear processed portion.

Further, a pinion 147 of fig. 2AH is obtained by hobbing the outer peripheral surface of the preform 146, which is the second gear processed portion. The outer diameter of the ring gear 142 can be increased or decreased to some extent according to the degree of rolling (rolling), and therefore the pinion 147 having a desired outer diameter can be molded from the second preform 130 without waste.

As described above, according to the manufacturing method of the present invention, it is not necessary to generate scraps (scraps 246) as in the conventional manufacturing method, and therefore, it is effective to reduce the cost of the ring gear 142 and the pinion 147. Further, by performing the forging of the ring gear 142 and the pinion 147 in a set, not only the material cost but also the manufacturing cost can be suppressed.

(mold apparatus)

Fig. 2BA to 2BF are schematic diagrams of the die equipment used for the hot forging. The mold apparatus is basically constituted by an upper mold and a lower mold (the total number of molds is 25). The upper and lower dies are each composed of 1 or more dies. The upper dies and the lower dies are arranged concentrically.

When the upper mold is a movable mold and the lower mold is a fixed mold, the upper mold is driven by a press machine of 2500 to 3500t, for example. The heating temperature for hot forging is, for example, 900 to 1260 ℃.

Fig. 2BA shows an upper die A1 and a lower die a'2 which compress the raw material 100 in the up-down direction. The horizontal die a '1 and the lower die a'2 in fig. 2BB are integrated, and the outer diameter of the forged product 110 is restricted during upsetting. Fig. 2BC shows an upper die B1, a lower die B '2, and a transverse die B '1 (integrated with the lower die B ' 2) used for extrusion molding of the shaft-like portion 120 a.

Fig. 2BD shows upper molds C1, C2, lower molds C '2, C'3, and a transverse mold C '1 (integrated with the lower mold C' 2) for molding the disc-shaped portion 130 b. The outer diameter of the disc-shaped portion 130b is limited by the transverse mold C' 1.

Fig. 2BE shows upper dies D1, D2, and D3, lower dies D '2, D'3, D '4, and D'5, and a transverse die D '1 (integrated with the lower die D' 2) for thinning the circumferential boundary cross section of the shaft-shaped portion 130a and the disc-shaped portion 130b in the previous process fig. 2 BD. The outer diameter of the disc-shaped portion 140b is limited by the transverse mode D' 1.

Between the upper die D2 and the lower die D'3, the circumferential boundary cross section of the shaft-like portion 140a and the disc-like portion 140b is compressed to be thin. By thinning the circumferential boundary cross section in this way, the shaft-like portion 140a (second intermediate member 146) can be easily separated in the step 5 of fig. 2 BF. Further, the material flow radially outward is generated by the thinning, and the peripheral edge portion of the disk-shaped portion 140b is thickened in the axial direction (vertical direction).

In step 5 of fig. 2BF, upper dies E1, E2, E3 and lower dies E '1, E'2 are used. The outer peripheral portion of the disk-shaped portion 140b is sandwiched and fixed from the top-bottom direction by the upper die E1 and the lower dies E '1 and E'2.

In this state, the shaft portion 146 is pressed downward by the upper dies E2 and E3 to be separated from the disk portion 140 b. Since the separation line 140c is thinned, the punching pressure at the time of separation can be reduced, the load on the punching punch can be reduced, and the punch life can be extended.

(axial continuation position of disk-shaped part and shaft-shaped part)

Fig. 3 is a diagram showing the influence of the difference in the axial continuation positions of the disk-shaped portion 140b (ring gear preform) and the shaft-shaped portion 140a (pinion preform) on the separability of the two. The mold shape of fig. 3 is simplified from fig. 2BA to 2 BF.

The slightly larger outer diameter portion of the shaft-like portion 140a in fig. 3 is a position where the second gear processed portion of the pinion gear is to be formed. The inner diameter side of the disk-shaped portion 140b is continuous with the position to be formed. In fig. 3, the left end row is a case where the axially continuous position is the upper side, the center row is a case where the axially continuous position is the center, and the right end row is a case where the axially continuous position is the lower side. In addition, the axial length of the continuous portion is a thinned dimension a in the left end row of fig. 3, but thinning is omitted for the other dimension B, C (a < B = C).

In the present embodiment, as shown in the left end row of fig. 3, the axially continuous position of the disk-shaped portion 140b (ring gear preform) and the shaft-shaped portion 140a (pinion preform) is located on the upper side. The upper position is an axial end portion on the opposite side to the direction in which the shaft-like portion 140a is pressed in the separating process.

By continuing the two at this position, the strain generated on the outer peripheral surface of the shaft-like portion 140a (the position to be formed in the second gear processed portion) is reduced from the initial stage of separation to the intermediate stage of separation, and the number of machining steps after separation can be reduced. The reduction in strain is presumed to function favorably in the above-described thinning dimension a.

In contrast, when the axially continuous position is located on the lower side as in the right end row in fig. 3, a large inclination NG1 is generated due to separation resistance at the lower step portion of the outer peripheral surface of the shaft-like portion 140a at the initial stage of separation. In addition, in the middle stage of separation, a large bulge NG2 is generated at the upper step portion of the outer peripheral surface of the shaft-like portion 140a due to the separation resistance. The lower inclination NG1 is reduced to some extent by making the dimension C thin (to the dimension a), but the upper bulge NG2 is rather large. This is because the distance from the continuous position before separation to the completion of separation is long, and therefore the amount of material movement becomes large.

In addition, when the axially continuous position is centered as in the center row of fig. 3, no particular problem is found at the initial stage of separation. However, in the middle stage of separation, a slight bulge NG3 is generated at the upper step portion of the outer peripheral surface of the shaft-like portion 140a due to the separation resistance. This is because the distance from the continuous position before separation to the completion of separation is longer than that in the present embodiment (left end row), and therefore the amount of material movement increases accordingly.

In this way, when the axial direction continuous position of the disk-shaped portion 140b (ring gear preform) and the axial direction continuous position of the shaft-shaped portion 140a (pinion preform) are not located on the upper side, the inclined and bulged deformed portions (NG 1 to NG 3) need to be corrected by machining after separation, and the number of processes increases accordingly, which leads to an increase in cost.

While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible. For example, although the second preform 130 is molded through 1 to 3 steps from 0 step (material) in the above embodiment, the second preform 130 may be directly molded from 0 step (material) depending on the kind of the raw material and the shape of the second preform 130. In this case, the steps shown in fig. 2BB and fig. 2BC can be omitted.

Claims

1. A method of manufacturing a ring gear and a pinion, comprising:

a first step of forming an intermediate member by hot upsetting a columnar material, the intermediate member having a disk-shaped portion as a preform of a ring gear and a shaft-shaped portion of the preform as a pinion extending from a center of the disk-shaped portion in one side direction in an axial direction;

a second step of pressing a circumferential boundary cross section between the disk-shaped portion and the shaft-shaped portion by using upper and lower dies to reduce the thickness of the disk-shaped portion and the shaft-shaped portion;

a third step of separating the shaft-like portion from the disk-like portion at the thinned circumferential boundary cross section by pressing the shaft-like portion in one side direction in an axial direction;

a fourth step of forming a first gear-formed portion on an outer peripheral surface of the annular member, the annular member being obtained by separating the shaft-like portion from the disc-like portion in the third step, the first gear-formed portion being formed to be a gear in a subsequent step, while the annular member being enlarged in diameter by rolling; and

a fifth step of forming a second gear processing portion for processing into a gear in a subsequent step on the outer peripheral surface of the shaft-like portion separated in the third step,

in the first step and the second step, a continuous position where the disk-shaped portion and the shaft-shaped portion are continuous is provided at a position where the second gear processing portion is to be formed, and at an axial end portion on a side opposite to a direction in which the shaft-shaped portion is pressed in the third step.

2. The method of manufacturing a ring gear and a pinion according to claim 1, characterized in that, in the first step, the shaft-like portion is molded by forward extrusion of the material in one side direction in an axial direction, and then the disk-like portion is molded.

3. The method of manufacturing a ring gear and a pinion according to claim 1, wherein in the first step, the columnar material is pressed by a first upper and lower die to form a forged product having a ratio of an axial length to an outer diameter of 85% to 95%, the forged product is pressed by a second upper and lower die to extrude the forged product forward in one axial direction, thereby forming the shaft-like portion, and thereafter, a base end side of the shaft-like portion is pressed by a third upper and lower die to expand the base end side, thereby forming the disk-like portion.

4. The method of manufacturing a ring gear and a pinion according to any one of claims 1 to 3, characterized in that, in the second step, a peripheral edge portion of the disk-shaped portion is thickened by a material flow radially outward due to the thinning.