JPS60261638A - Manufacture of gear provided with boss - Google Patents

Abstract

PURPOSE:To manufacture a gear with a boss of a good shape in good yield and with high efficiency by inserting a forming material with bosses into a die hole with a lower tooth form, forming a tooth form on the base material by a guide pressure of an inside punch of a punch and an outside double structure punch, and punching it by the inside punch. CONSTITUTION:A ring hole forming material 40 with boss is inserted into a die 16 hole 16a having a tooth form 16b on the lower part. The material 40 is pressed by an inside punch 28 fitted into a ring hole of a punch, a tip part 28b and an outside double-structure punch 32. As for the material 40, a tooth form 41b is formed on the outside. A punch 28 whose diameter is slightly smaller than the bottom part of the tooth form descends further against a spring 29 and punches a tooth form forming material 41. A ring hole gear with a boss of a good shape is manufactured in a good yield and at high efficiency by its descending process of once. In this regard, as for an elongated part of the tooth form, it will do that it is finished by a lathe.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a bossed gear which is applied to manufacturing the bossed gear by extrusion molding.

(Prior Art) As a conventional method for manufacturing a gear with a boss, there is a method that goes through the process shown in FIG. 1, for example. In this method, Figure 1 (a
) as shown in the boss part 1a, tooth forming part 1b, and hollow part 1.
A bossed gear material 1 having a boss gear material 1 is made by hot forging, and the inner periphery and both end faces of the boss gear material 1 are cut to form a machined boss as shown in FIG. 1(b). Make attached gear material 2. Next, by hobbing and shaving the outer periphery of this machined gear material 2 with a boss, a tooth profile 3 as shown in FIG. 1(c) is formed, and the tooth profile 3 and the boss 4. This is a method of obtaining a bossed gear 5 having the following.

However, in such a conventional manufacturing method for gears with bosses, the tooth profile portion 3 is formed by machining, which results in a large amount of cutting waste, resulting in a poor material yield. There is a problem in that the grain flow lines produced by hot forging during the production are cut and the strength of the tooth profile part 3 is reduced, and in addition, there is a problem in that cutting the tooth profile part 3 requires a large number of man-hours. there were.

Therefore, in order to solve the problems associated with forming the tooth profile portion 3 of the boss gear 5 by machining,
For example, there is also a method as disclosed in US Pat. No. 3,910,091. This method uses a die in which a die hole is provided with an internal tooth mold for forming a tooth shape, and a first cylindrical gear material is inserted into the die hole halfway up the internal tooth mold using a mandrel and a punch. After press-fitting, a second cylindrical gear material is placed on -1- of this cylindrical gear material, and these two gear materials are simultaneously press-fitted into the die hole using the mandrel and die, and the first cylindrical gear material that was previously press-fitted is A tooth profile is formed on the outer periphery of the first gear material. Then, by placing a third cylindrical gear material on top of the first and second gear materials, and press-fitting this gear material into the die hole using the mandrel and die, The first gear material, on which the tooth profile has already been formed, is extruded from the die hole, and the tooth profile is formed on the outer periphery of the second gear material in one of the die holes, which is a so-called patching method. .

However, in such a piecing method, a tooth profile is formed on the outer periphery of the second gear material while pushing the second gear material one level below it with the third gear material located at the top. At the same time, since the first gear material on which the tooth profile has already been formed is extruded from the die hole, bosses that do not have the same shape in the horizontal cross section may be used to manufacture spur gears that have the same shape in the horizontal cross section. In order to manufacture a gear, a bossed cylindrical gear material 1 having a boss portion 1a and a tooth forming portion 1b as shown in FIG. 1(a) is prepared, and this gear material 1 is used to form a boss portion 1a. When attempting to extrude the same way as for the spur gear above with the cylindrical gear facing downward, the upper end surface of the tooth forming part 1b of the cylindrical gear material of the boss 41 that has been press-fitted into the die hole and the newly inserted Since the boss 1a of the bossed cylindrical gear material comes into contact with the lower end surface of the boss 1a, the boss portion 1a is crushed when the gear material 1 is press-fitted into the die hole, making it impossible to form a bossed gear. There was a problem.

(Object of the Invention) The present invention has been made by paying attention to such conventional problems, and has a double structure for the punch for press-fitting the bossed gear material into the die hole. While press-fitting the gear to the internal tooth mold for the tooth forming shape in the die hole, the double structure punch is used to press the entire tooth forming shape side end surface of the boss gear material, and then the double structure punch To manufacture a well-shaped bossed gear with high yield and high efficiency by pushing out the bossed gear with a tooth profile from a die hole by pushing only with the inner punch. It is an object.

(Structure of the Invention) When manufacturing a boss gear having a tooth profile on the outer periphery and a boss on one end, the present invention includes a die having an internal tooth die for tooth formation on the inner circumference of the die hole. A gear material with a boss having a boss portion at one end is inserted with the boss portion facing downward, and an annular outer punch having an outer diameter slightly smaller than the root diameter of the internal tooth type and a tooth of the internal tooth type are inserted. A double-structured punch in which an inner punch having an outer diameter slightly smaller than the tip diameter is fitted concentrically and slidably to each other is inserted into the outer punch from the tooth forming side end surface of the bossed gear material. The gear is pressed to a position immediately before contacting the tooth mold, and then only the inner punch is pressed to extrude the molded gear with a boss from the inner tooth mold, so that the gear with a boss forms a cylindrical shape. In this case, a cylindrical material is used as the bossed gear material, and the double-structured punch is provided with a mandrel that fits into the cylindrical inner hole.

(Embodiment) FIGS. 2 to 5 are diagrams showing an embodiment of the present invention. In FIG. 2, 11 is a lower bolster of the press, and a base plate 12 is placed on this lower bolster 11, and is fixed to the lower bolster 11 with fastening members 13 and bolts 14. This base plate 12 is provided with a hole opening 12a so that the bossed gear can be taken out after molding. Also, base plate 1
A die 16 is installed on the second side of 2 with a pressure receiving plate 15 interposed therebetween.
It is fixed to the base plate 12 by 8. A die hole 16a is formed in the die 16, and an internal tooth mold 16 for forming teeth is formed in about the lower half of the die hole 16a.
b is formed.

On the other hand, 21 is an upper bolster of the press, and a base plate 22 is disposed on the bottom side of the lower bolster 21, and is fixed to the lower bolster 21 with fastening members 23 and bolts 24.

The base plate 22 has a bottom outer peripheral portion for positioning (@R#
25 ' * Jlz F 26°°J"'I"611
6. Also, an inner punch insertion hole 22a is formed in the center of the base plate 22, and a coil spring installation hole 22 is formed on the second part side of the inner punch insertion hole 22a.
b is formed. Then, the inner punch insertion hole 2
2b, an inner punch 28 constituting a double-structured punch 27 is vertically slidably disposed. The inner punch 28 is held in a flange portion 28a provided at the upper end thereof, and the inner punch 28 is always urged upward. At this time, the upper end of the inner punch 28 is positioned so as to be in contact with the lower end of the sub-bolster 30 of the press. Further, a mandrel 2 with an outer diameter corresponding to the inner diameter of the cylindrical gear to be manufactured is attached to the lower end of the inner punch 28.
8b is integrally formed. Further, on the bottom surface side of the base plate 22 and on the outer peripheral side of the inner punch 28, an annular outer punch 32 that constitutes a double-structure punch 27 together with the inner punch 28 is in a state where the inner punch 28 can be slid. This outer punch 32
is fixed to the bottom surface of the base plate 22 by a fastening member 33 and a bolt 34.

Here, the outer punch 32 is formed to have an outer shape slightly smaller than the bottom diameter of the internal tooth mold 16b formed on the inner circumference of the die 16, and the inner punch 28 is formed to have an outer diameter S slightly smaller than the tooth bottom diameter of the internal tooth mold 16b formed on the inner circumference of the die 16. The outside diameter is slightly smaller than the tooth tip diameter.

Next, the operation of the apparatus configured as described above will be explained with reference to FIGS. 3 to 5.

First, by performing hot forging, warm forging, or cold forging, and then cutting, a boss portion 40a, a tooth forming portion 40b, and a hollow portion 40c are formed as shown in FIG. 5(a).
A gear material 40 with a cylindrical boss is prepared. Next, as shown in FIG. 2, after inserting the gear material 40 with a boss into the die hole 16a of the die 16 with the boss portion 40a facing downward, the upper bolster 2 of the press
Lower 1. Therefore, as the upper bolster 21 descends, the inner punch 28 with the mandrel 28a is positioned upward by the sub-bolster 30 of the press.
and the outer punch 32 descend together to press the tooth-forming end surface of the gear blank 40 with a boss downward, and press-fit the tooth-forming part 40b of the gear blank 40 with a boss into the internal tooth die 16b of the die 16. do. When this press-fitting progresses and the lower end of the outer punch 32 reaches a position just before contacting the upper end of the internal tooth die 16b, the lower end of the positioning member 25 is placed above the die 16, as shown in FIG. At this position, the upper bolster 21 stops descending, and at the same time, the outer punch 32 also stops descending. In this state, the tooth forming portion 40b of the bossed gear material 40 is at the position of the internal tooth mold 16b.

Then, the contact of the lower end of the positioning member 25 with the upper end surface of the die 16 is detected by a pressure switch (not shown) installed in the hydraulic system of the press main ram, or a limit switch capable of detecting the movement of the main ram. In response to this detection signal, the upper sub-ram 30 is further lowered, and at the same time, the inner punch 28 with the mandrel 28b is lowered while compressing the coil spring 29. Therefore, since the inner punch 28 is formed to have an outer diameter slightly smaller than the inner diameter of the tooth tip of the internal tooth die 16b, only the end surface on which no tooth profile is formed of the two wheel surfaces of the gear material 40 with a boss on the tooth profile side] Pressed by the inner press 28, the bossed gear 41 is formed, as shown in FIG. 4, in which the boss portion 41a at the lower end remains undeformed and toothed portions 41b are formed on the outer periphery. During this time, the mandrel 28b remains fitted inside the cylindrical gear material 40 with a boss, so it is possible to prevent the material from flowing toward the inner circumference of the gear material 40 with a boss. A bossed gear 41 having a central hole 410 with an inner diameter is obtained.

After this, the main ram and upper sub-ram of the press are moved forward, the bossed gear 41 is pulled out from the mandrel 28b and falls onto the lower bolster 11, and the main ram and upper sub-ram are moved to the position at the start of machining. During this time, the upper end of the inner punch 28 is constantly in contact with the lower end of the upper sub-ram 30 due to the repulsive force of the coil spring 22. after that,
The next gear material 40 with a cylindrical boss is inserted into the die hole 16a of the die 16 with the boss portion 40b facing downward, and the same process is repeated. On the other hand, the bossed gear 41 that has fallen onto the lower bolster 11 is taken out through the opening 12a formed in the base plate 12.

FIG. 5(b) shows the bossed gear 41 taken out from the opening 12a. Although the shape of the boss part +1& of this bossed gear 41 is good, the front end of the toothed part 41b in the extrusion direction Since A is deformed toward the toothed portion 41b side and the rear end side B flows backward, it is necessary to remove it by machining. Therefore, the inner diameter portion of the hollow portion 410 is ground, and the outer periphery and both end surfaces of the boss portion 41& are lathed.Then, the front and rear sides of the toothed portion 41b are shaped using a lathe, and then the toothed portion 41b is shaved. By processing, the boss portion 4 as shown in FIG. 5(C) is formed.
2a, a toothed part 42b, and a hollow part 42C. (Manufacturing example) A cylindrical bossed gear material 40 is formed by cold forging from a bar of JIS standard SCR420H, and then the boss The gear material 40 was subjected to spheroidizing annealing and lubrication treatment. Next, the bossed gear material 40 was charged into the die 16 of the apparatus shown in FIG. 2, and the bossed gear 41 was manufactured through the steps shown in FIGS. 2 to 4. Next, the bossed gear 41 is finished to form module 2.5.
．． Helix angle 22°, tooth a22. Standard pitch circle diameter 59.3
19mm, outer diameter 64.5mm, tooth length 3 [■, inner diameter 3
8.2+n+, shaft outer diameter 52m+s, total length 64.5mm
A bossed gear 42 was manufactured. In this case, the gear with boss 4
No. 1 could be molded at a rate of 9 to 10 pieces/min. Further, depending on the machining rate of the tooth profile portion 41b, that is, the cross-sectional reduction rate, the gear material 40 with a boss extends in the axial direction during the process of being press-fitted into the internal tooth mold 16b formed in the die hole 16a. 40 is the bossed gear 4 after molding
It was necessary to use a material having the same volume as No. 1 and a length of 1-km in the axial direction. Thus, compared to the case where the bossed gear 5 is manufactured by machining using the conventional hot forged gear material 1, when the bossed gear 41 is manufactured using the double structure punch 27, , about 0 in total machining time
．． 8 minutes, an approximately 35% improvement in material yield was achieved.

(Effects of the Invention) As described above, according to the present invention, when manufacturing a gear with a boss having a tooth profile on the outer periphery and a boss on one end, a tooth forming shape is provided on the inner circumference of the die hole. A gear material with a boss having a boss portion at one end is charged into a die having an internal tooth type with the boss portion facing downward, and an annular outer part having an outer diameter slightly smaller than the bottom diameter of the internal tooth type is inserted. punch and
A punch with a double structure in which an inner punch having an outer diameter slightly smaller than the tooth tip diameter of the internal tooth type is fitted concentrically and slidably to each other is inserted from the side end surface of the tooth forming shape of the gear material with boss. The outer punch is pressed to a position just before contacting the inner tooth mold, and then only the inner punch is pressed to push out the molded gear with a boss from the inner tooth mold, so that the boss 4 has a good shape. = 1 gear can be manufactured with good yield and high efficiency, which can bring about an extremely excellent effect.

[Brief Description of the Drawings] Figures 1 (a), (b) and (c) are explanatory diagrams showing changes in the shape of the bossed gear material during the manufacturing process of conventional bossed gears;
FIG. 2 is an explanatory longitudinal cross-sectional view of a manufacturing apparatus used in an embodiment of the method for manufacturing a bossed gear according to the present invention, and FIGS. 3 and 4 are longitudinal cross-sectional explanatory views showing changes in the movement of the apparatus shown in FIG. 2. 5(a), 5(b) and 5(c) are explanatory diagrams showing changes in the shape of the bossed gear material during the manufacturing process of the bossed gear according to the present invention. 16...Dice, 16a...Dice hole 1. 1. 16b...internal tooth type, 27...double structure punch, 28...inner punch, 32...outer punch, 40...gear material with boss. 40a...Boss part, 40b...Tooth forming part, 41.42...Gear with boss, 41 & + 42a...Boss part, 41b, 42b
...Tooth profile. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Yutaka Oshio 227- Figure 4 Figure 5 229-

Claims (1)

[Claims] (1) When manufacturing a gear with a boss that has a tooth profile on the outer periphery and a boss on one end, the boss has a boss on one end in a die that has an internal tooth die for tooth formation on the inner circumference of the die hole. A gear material with a boss is loaded with the boss portion facing downward, and an annular outer punch having an outer diameter slightly smaller than the root diameter of the internal tooth type and a tooth tip diameter slightly smaller than the tooth tip diameter of the internal tooth type are inserted. A double-structured punch in which an inner punch having an outer diameter and an inner punch are fitted concentrically and slidably to each other is inserted from the tooth forming shape side end surface of the bossed gear material just before the outer punch contacts the inner tooth mold. 1. A method for manufacturing a bossed gear, which comprises pressing the bossed gear to a position, and then pushing only an inner punch to extrude the molded bossed gear from the internal tooth die.