JPH04210839A - Method and device for releasing spiral gear or the like from die - Google Patents

Abstract

PURPOSE:To efficiently manufacture a spiral gear, etc., in low cost by releasing a formed raw material from a die to tooth height direction while relatively displacing to a tooth face separating direction to the die in a lower die block. CONSTITUTION:The gear raw material W is forged with the die 5 for forming spiral teeth in the lower die block 2 and a punch 13 in an upper die block 3 in the dies 1 for forging the tooth form. Thereafter, the formed raw material W is released from the die 5. Then, the formed raw material W is released to the tooth height direction while relatively displacing to the tooth face separating direction to the die 5 in the lower die block 2. In the lower die 2 a die knock-out 6 capable of vertical movement accompanied with the rotation at the center part of the die 5 for forming the spiral teeth is provided. At the time of forging an engaging part is formed in the raw material W with the die knock-out 6 and also at the time of releasing from the die, by rotating the die knock-out 6, the raw material W is rotated together at the engaging part to release it from the die. By this method, the formed tooth can be prevented from deformation caused by interference, etc.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold release method and apparatus for smoothly releasing a molded material from a die after forming a spiral gear or the like by forging. [0002]

[Prior Art] For example, differential gears used in power transmission mechanisms of automobiles or agricultural machinery use bevel gears such as spiral bevels or staggered shaft gears such as hypoid gears. For such spiral gears, the gear portion is generally manufactured by cutting a blank formed by forging or rolling using a special gear cutting machine such as a Gleason machine. However, when machining with a special gear cutting machine like this, the manufacturing cost is extremely high because the gear cutting machine is expensive.
Since it is necessary to carry out two steps of rough gear cutting and finish gear cutting, which take 4 to 5 minutes, there is a problem that the gear cutting time becomes long and productivity is poor. Particularly in recent years, for example, when molding components into automobiles that aim to produce high output due to the trend towards higher-end products, reduction of noise and vibration and improvement of durability are required, so tooth grinding, lapping, etc. Improvements in tooth contact, such as finishing, were required, which required many processes and labor, and was a factor in rising manufacturing costs. On the other hand, there are some documents and reports on forming gear parts such as bevel gears by precision forging, and they are mainly introduced as gears with straight tooth traces that are easy to apply, such as straight bevel gears. Manufacturing gears using this forging method has the advantage of omitting the complicated gear cutting process and shortening the process time, and also reduces equipment costs by eliminating the need for expensive gear cutting machines. This was desirable because it became [0003]

[Problems to be Solved by the Invention] However, when attempting to manufacture such a gear molding by forging, for example, a spiral gear whose tooth profile has an undercut on one side of the tooth surface, there is a problem of mold release. It was supposed to happen. In other words, even if helical teeth are formed on the material using an undercut mold release provided on the die, if you try to release the mold as is, the tooth pattern on the mold side and the molded teeth of the molded material will interfere with each other, causing the molded teeth to become deformed. A situation could arise that would result in a loss of precision. [0004]

[Means for Solving the Problems] In order to solve the problems, the present invention forges a gear material using a lower spiral tooth forming die and an upper punch, and then transfers the forming material to the lower die. The mold is released in the tooth depth direction while causing a relative deviation in the tooth surface separation direction. In addition, a die knockout that can move up and down with rotation is provided in the center of the die of the lower mold, and an engaging part is formed in the material by the molded part of the upper surface of the die knock, and the rotation of the die knockout is controlled by the retaining part. It was decided that the vibration would be transmitted to the material through the tooth surface, causing a relative deviation in the tooth flank separation direction. [0005]

[Operation] By releasing the molding material while rotating it in the tooth flank separation direction, interference between the tooth pattern on the mold side and the molded tooth can be avoided, even in the case of undercut tooth flanks, for example.
There is no risk of deformation or deterioration of accuracy. [0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the method and apparatus for releasing a spiral gear, etc. of the present invention will be described with reference to the attached drawings. 1 to 3 are state diagrams showing the process of tooth molding using a tooth forging die, and FIG. 4 is a plan view of the die knockout. The mold release device of the present invention includes a tooth profile forging die 1 as shown in FIG.
The spiral teeth are formed on the material W by hot forging, thereby eliminating the need for a gear cutting process. The tooth profile forging die 1 includes an upper die 3 that opens and closes by moving up and down with respect to a lower die 2, and processes a material W positioned between the two by hot forging. The lower mold 2 includes a die 5 provided on a die holder 4 and a die knockout 6 provided in the center, and the die 5 has a ring-shaped forging tooth profile 7 formed therein. [00071 The shape of the tooth pattern 7 of the die 5 is such that the tooth trace is spiral in order to form the finished material W as shown in FIG. 7, for example, a spiral bevel gear, and one tooth surface 8 as shown in FIG. is in the Ashida cut shape, and the required amount of back taper is applied. Incidentally, such a forged tooth pattern 7 of the die 5 is formed with high precision by, for example, electrical discharge machining. [0008] On the other hand, the die knockout 6 can be freely raised and lowered by a knockout bin 9 located below, and a plurality of outer circumferential ribs 10 are provided on the outer periphery of the die knockout 6 in a circumferential direction, and are provided on the die holder 5. It engages with the lead groove 11. Since the outer ring 10 and the lead groove 11 are inclined in the vertical direction, the die knockout 6 lifted by the knockout pin 9 rises while rotating around the vertical central axis. Further, the direction of this inclination is such that the forming material W rotates toward the side of the side cut tooth surface 8 of the forged tooth die 7, as shown in FIG. Of course, the relationship between the outer peripheral rib 10 and the lead groove 11 may be reversed, that is, the lead groove may be provided on the outer periphery of the die knockout 6, and the rib may be provided protrudingly on the die holder 4 side. [0009] On the other hand, a plurality of engaging protrusions 12 are provided in the circumferential direction on the upper peripheral edge of the die knockout 6 as molded parts. That is, as shown in FIG. 4, for example, four engaging concave portions 12 are provided at equal intervals on the circumference, and the engaging convex portions 12 form concave portions Wo as engaging portions in the material W and engage the two. Thus, when the die knockout 6 rotates, the molding material W is rotated. The shape of the engaging convex portions 12 is not limited to a convex shape, but may be a concave shape, and it goes without saying that four or more engaging convex portions 12 may be provided. On the other hand, the upper die 3 is equipped with a punch 13 having a forming portion 14 on the lower surface thereof, and as described above, the die is opened and closed by moving up and down. [00101 A method for forging and releasing a spiral gear etc. using the toothed forging die 1 having the above configuration is as follows. First, a disk-shaped material cut out from a material is roughly formed and positioned on the lower mold 2 shown in FIG. Material W at this time
As shown in Fig. 1, the shape of the forging hole may be pre-drilled in the center, or may not be formed, but it is better to punch a hole from the beginning to reduce the forging pressure. This is more preferable. [0011], 1 m (7) molding, for example, the material W is about 1
It is hot forging performed by heating to about 150℃, and the
The forging is performed at a forging pressure of 0 to 1500 tons. Then, a recess W is formed on the lower surface of the material W by the tooth profile formed by the forged tooth mold 7 and the engagement convex portion 12. (FIG. 5) is formed, and the upper surface of the material W is formed by the punch forming section 14. Incidentally, the recessed portion W◯ formed by the engagement convex portion 12 is formed in the flat portion W1 of the inner peripheral edge of the material, as shown in FIG. Then, this paris W1 is removed in the final step. Incidentally, FIG. 7 shows a case where the recessed portions W◯ are formed at eight locations, and is an example of a case where the molding is performed using a mold provided with eight engaging convex portions 12. [00121 Next, as shown in FIG. 3, when the punch 13 rises, the knockout bin 9 moves upward, and the die knockout 6
is raised while rotating due to the engagement between the outer circumferential tube 10 and the lead groove 11. This rotation is also reliably transmitted to the molding material ~■ which engages the engagement convex portion 12 of the die knockout 6 with the recess W○, causing a situation such as a slip between the die knockout 6 and the molding material W. does not occur. The direction of rotation is in the direction of the side cut tooth surface 8 of the tooth profile 7 in FIG.
Since the inclination of 0 is set at an angle that allows the tooth profile of the molding material W and the tooth profile 7 of the die 5 to be pulled out without causing interference during mold release, the mold can be released smoothly and reliably, and the molded teeth can be removed. There is no risk of deformation, etc. And this molding material W is
At the end of another forging process, etc., the tooth profile accuracy is improved and the finished product is obtained. The forging method of the present invention as described above can be applied not only to spiral bevel gears but also to hypoid gears and the like. [0013]

Effects of the Invention As described above, the mold release method and device of the present invention can release the forging of spiral gears, etc., while rotating the die knockout, which has conventionally been difficult due to problems such as mold release properties. Since an engaging portion is provided that reliably transmits the rotation of the die knockout to the material, it is possible to reliably prevent problems such as deformation of the prepared tooth due to interference or a decrease in accuracy. This makes it possible to eliminate the complicated gear cutting process that was previously performed.
It has become possible to manufacture at low cost and with high efficiency.

[Brief explanation of the drawing]

[Figure 1] Diagram of the opening state of a toothed forging die

[Figure 2] Diagram of the closed state of the toothed forging die

[Figure 3] Diagram of the release state of the toothed forging die

[Figure 4] Plan view of die knockout

[Figure 5] Recessed part formed in the material as an engaging part

[Figure 6] Partially enlarged sectional view showing the relationship between the tooth profile of the mold and the tooth profile of the material

[Figure 7] Perspective view of molding material

[Explanation of symbols]

1　Tooth type forging mold 2 Lower mold 3 Upper mold 6 Die knockout 10 Outer circumference block 11 Lead groove 12. Retaining convex part as a molded part W Material Wo　Recessed part as an engaging part

Claims (3)

[Claims] 1. A mold release method for forging a gear material using a spiral tooth forming die in a lower die and a punch in an upper die, and then releasing the forming material from the die. A method for releasing a spiral gear, etc., characterized in that the mold is released in the tooth depth direction while being relatively displaced in the tooth flank separation direction with respect to a die. 2. The lower mold is provided with a die knockout that can be moved up and down with rotation in the center of the spiral tooth forming die, and the die knockout forms an engaging part in the material during forging and also separates the material. 2. The method for releasing a spiral gear or the like according to claim 1, wherein during molding, the die knockout is rotated to rotate the material at the engaging portion and release the material from the mold. 3. A mold release device for forging a gear material using a lower spiral tooth forming die and an upper punch, and then releasing the formed material from the die. A die knockout is provided in the center that is movable up and down and rotatable around a vertical axis, and a molded part for forming an engaging part in the material is provided on the upper surface of the die knockout, and on the side thereof, A mold release device, such as a spiral gear, characterized by being provided with a rotation means for rotating the die knockout.