JPS6228040A - Extrusion molding method for gear wheel - Google Patents

Abstract

PURPOSE:To form the gear wheel having a perfect tooth profile with high productivity by forming a tooth profile on the outer peripheral part of a gear wheel blank through the tooth profile forming part of a die in the state of both pressing by pinching the gear wheel blank with a pressure punch and back pressure punch. CONSTITUTION:A flat cylindrical blank 31 is made in the both pressing state of pinching it between punches 10, 21 by supporting it to a back pressure punch 21, by penetrating the mandrel 11 of the pressure punch 10 through the center hole 31a and by descending a pressure sleeve 12. With descending the punch 10 further the outer peripheral face of the blank 31 is transferred from the tooth profile lead-in part 2b of a die 2 to a tooth profile forming apt 2a, but the tooth profile formation is stopped when the lower end of the sleeve 12 comes to the just above position of the lead-in part 2b. The formation is repeated similarly after charging the following blank 31 on the helical gear 32 under working and the whole tooth profile of the gear 32 and the partial tooth profile of the bland 31 are formed. The gear wheel of thigh accuracy can thus be formed with high productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a method of extrusion molding a float used for manufacturing gears by extrusion molding.

(Prior Art) There have been several methods for manufacturing gears using extrusion molding, but the helical (oblique) gear manufacturing apparatus for carrying out this conventional method is, for example, the fifth gear manufacturing method. There is something like the one shown in Figure 8 (for example, Japanese Patent Application Laid-Open No. 51-20060
(see publication).

This gear manufacturing device has a movable part and a fixed part, and the movable part is comprised of a sleeve 101 and this spring 11-n.
1 rb L, -rFA, lゝ, hh l” = to l
-h -y ・t V' 1. +1°102. The sleeve 101 and mandrel 102 are fixed to an upper bolster of a press (not shown) and can be moved up and down. On the other hand, the fixed part includes a container 103 into which the sleeve 101 can be inserted, and a tooth forming part 104 corresponding to the tooth profile of the helical gear to be formed.
The container 103 and the die 104 are integrally fixed by an annular fixing member 105. This annular fixing member 105 is fixed to the lower bolster 106 with a lower pressure receiving member 107 interposed therebetween.

Next, to explain the movement of this 'A'ja, first,
In a state where the sleeve 101 and the mandrel 102 are FA'd and removed from the container 103, the cylindrical gear material 110 is charged into the container 103. Next, when the sleeve 101 and the mandrel 102 are lowered into the container 103 by the lowering of the upper bolster (not shown), the mandrel 102 is fitted into the cylindrical tooth jVj material 110, and the cylindrical gear material 110 is connected to the die 10 by the sleeve 101.
The helical gear 111 is pushed in to the tooth profile introduction part 104b and the tooth forming part 104a of No. 4, and is in the middle of the front opening. At the same time, helical gear 111, which is already in the process of being machined,
The helical float 112 passes through the tooth forming portion 104a and has a predetermined tooth profile. At the same time, the helical gear 112, which has already been formed with teeth by the tooth forming section 104a, is dropped from the die 104. Subsequently, after the sleeve 101 and the mandrel 102 are raised, a new cylindrical gear material 110 is charged into the container 103, and the above-described processing cycle is repeated.
One helical gear 112 is formed per processing cycle.

(Problems to be Solved by the Invention) According to such a conventional gear extrusion method,
Compared to the conventional gear forming method using cutting, the material yield is significantly higher and the productivity is also superior. Since it was a one-way push method in which pressure was applied from only one direction by the sleeve 101 and pushed into the die 104, it was especially difficult to mold the thin helical gear 112 with a relatively small height by pressing. In this case, if a thin material is used as the gear material 110, it is likely to be deflected when pressed by the sleeve 101, so that the helical gear 112 after extrusion molding is
In this case, a lack of thickness or warping may occur at the tip of the tooth. For example, as shown in an exaggerated manner in FIG. 9, the tip of the tooth is warped toward the sleeve 101, resulting in an S state.

If a lack of fillet occurs in this way, the gear will have an incomplete tooth profile, and if warpage occurs, the gear will have an incomplete tooth profile. There were problems such as increased manufacturing costs.

This invention was made by focusing on the conventional problems as mentioned above, such as warping of gears after press molding,
The purpose of the present invention is to provide a gear extrusion molding method capable of molding a float having a perfect tooth profile with high productivity by extrusion molding without causing a lack of thickness at the tip of the tooth.

"Structure of the Invention" (Means for Solving the Problems) The extrusion molding method for gears according to the present invention is applied to molding gears having tooth profiles on the outer periphery by extrusion molding. A gear blank is placed concentrically on one side in the direction of the central axis of a die having a tooth forming portion corresponding to the chevron of the gear, and a pressure punch is pushed in from one side of the die to press one side of the gear blank. At the same time as pressing, a back pressure punch is pressed against the other surface of the gear material from the other side of the die to apply back pressure, and the gear material is sandwiched between the pressure punch and the back pressure punch in a double pressed state. By passing through the tooth forming part of the die, the outer circumferential portion of the gear material is formed with straight teeth (straight and upper teeth).

It is characterized by the formation of tooth profiles such as helical (oblique m), splines, and serrations.

In the gear extrusion molding method according to the present invention, it is possible to mold gears that do not have a shaft hole in the center, but it is also possible to mold gears that have a shaft hole in the center. . In the case of extrusion molding the latter wheel having a shaft hole, in one embodiment, a cylindrical gear material is used as the gear material, and the pressure punch is a mandrel with an outer diameter corresponding to the shaft hole and a force roller. and a pressure sleeve concentrically, the back pressure punch has a fitting hole for the mandrel,
The mandrel of the pressure punch and the mandrel fitting hole of the back pressure punch fit together, and the cylindrical gear material is passed through the tooth forming part of the die in a double-pressed state in which the material is sandwiched between the two punches. A feature of this gear is that a tooth profile is formed on the outer circumferential portion of the cylindrical gear material.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, and the gear extrusion molding apparatus shown in the figure includes a fixed part and a movable part.

Among these, the fixed part has a container 1 and a die 2 arranged concentrically, and this die 2 has a shape corresponding to the tooth profile of the gear to be manufactured (for example, a helical gear). Tooth formation part 2a.

A continuous tooth profile introducing section 2b is provided at the upper end of this tooth forming section 2a. The container 1 and the die 2 are integrally fixed and held within a cylindrical die case 3. A ring-shaped spacer 4 is provided on the lower surface side of the die case 3, into which a bushing rod 5 for pushing out the gear after extrusion molding in the water direction is slidably inserted. It has a rod through hole 4a, and is also provided with an opening 4b at a position facing the bushing rod 5 for discharging the extruded gear to the outside of the device. The spacer 4 is fixed to a base plate 7 via a lower block 6, and the base plate 7 is fixed to a lower bolster 8 of the press. Furthermore, the spacer 4. At the center of the lower part 70, the base plate 7, and the lower bolster 8, □ indicates through holes 4c and 6a, respectively.
.

7a and 8a are provided.

The movable part of the device consists of an upper movable part and a lower movable part, and the upper movable part is connected to the central axis on the one side (upper side in the illustrated example) of the gear pitch circle center axis direction of the die 2. A gear material 31 (shown by imaginary lines) provided in a container 1 and a die 2 so as to be able to reciprocate concentrically can be pushed and pressed toward the tooth profile introducing section 2b and the tooth forming section 2a. A pressure punch 10 is provided.The pressure punch 10 includes a mandrel 11 having an outer diameter corresponding to the center hole 31a of the gear material 31, and a mandrel 11 which is arranged concentrically around the mandrel 11 and which has a diameter corresponding to the center hole 31a of the gear material 31. Pressure sleeve 12 that pushes the top surface of the
A mandrel 11 and a pressure sleeve 12 constituting this pressure punch 10 are both fixed to an upper bolster 13 of the press.

The lower movable part of the device is arranged concentrically with the weighting center axis on the other side of the gear pitch circle center axis direction of the die 2 (downward IN in the illustrated example), and the respective through holes 4c, 6a,
7a, back pressure punch 2 provided so as to be reciprocally interlocked within Ba
1. This back pressure punch 21 has a mandrel fitting hole 21a into which the mandrel 71 can be fitted, and also has a hollow hole 21b with a slightly larger diameter than this fitting hole 21a, and has a hollow hole 21b on the lower end thereof. is connected to a bushing rod 23 via a threaded sleeve 22, and can be raised and lowered by a drive mechanism (not shown).
Back pressure can be applied from the other side (lower side) of 1.

Next, the operation of the gear extrusion molding apparatus having the above structure will be explained based on FIGS. 2 to 6. In this description, a case will be described in which the gear to be molded is a helical gear having a shaft hole in the center.

In this example, the gear molding process basically consists of two-way pressure pressing, which repeats three steps: charging the gear material, pressurizing and extrusion molding, and removing the gear (product). It is.

First, the bushing rod 23 is driven by a drive device (not shown).
As a result, as shown in FIG. 2, the upper end surface of the back pressure bunch 21 is raised to a position approximately at the same level as the upper end of the tooth profile introduction part 2b formed in the die 2, and in this state, the die is stopped and waited.

Next, as shown in FIG. 2, a part-shaped cylindrical gear material 31 having a center hole 31a is placed inside the container 1 and the die z.
Charge. At this time, the cylindrical gear material 31 is supported by one end of the tooth profile introduction part 2b formed in the die 2, and the bottom surface of the cylindrical gear material 31 is on the upper end surface of the back pressure bunch 21. It is in contact. Note that these positional relationships are not particularly required;
It does not matter if there is a slight distance between the two.

Next, the northern bolster 13 of the press is lowered, and the mandrel 11 of the pressurizing bunch 10 is first placed on the cylindrical gear material 3.
1 through the center hole 31a, and then the back pressure bunch 21
The pressurizing sleeve 1 of the pressurizing bunch 10 is fitted into the mandrel fitting hole 21a of the pressurizing bunch 10, and the upper bolster 13 is roughly lowered.
2 into the container 1 and further lowered to apply pressure to the top surface of the cylindrical gear material 31 with the bottom surface of the pressure sleeve 12. Push state.

Subsequently, when the pressure bunch 10 is lowered with a pressure greater than the pressing force of the back pressure bunch 21, the cylindrical gear material 31 is lowered in a double pressed state sandwiched between both punches 10 and 21, and the cylindrical gear material The outer circumferential surface of the material 31 gradually moves from the tooth profile introduction part 2b to the tooth profile introduction part 2a of the die 2 to form a tooth shape, and as shown in FIG. When it comes to the position directly above both bunches 10°2
1 is stopped, and the helical gear 32 that is being processed is formed. As described above, the pressure applied by the pressure bunch 10 to the upper surface of the cylindrical gear material 31 is set to be always greater than the pressure applied to the lower surface of the cylindrical gear material 31 by the back pressure bunch 21. It is. In this case, the pressing force exerted by the back pressure bunch 21 is equal to
It is sufficient to set the value to the minimum value necessary to prevent sink marks from occurring and the outer peripheral end surface from bending when the outer peripheral portion of the die 2 passes through the tooth forming portion 2a of the die 2 and is formed into a tooth shape. It is. Further, the lowering limit position of the pressurizing bunch 10 is set immediately above the lower end of the pressing bunch 10 where it does not come into contact with the tooth profile introducing portion 2b of the die 2, as described above.

Then, the force 1 is increased by raising the upper bolster 13.
The one-pressure punch 10 is moved upward to separate the bottom surface of the pressure sleeve 12 from the helical gear 32 that is being formed, and the mandrel 11 is inserted into the mandrel fitting hole 21 of the back pressure bunch 21.
a and the center hole 32a of the helical gear 32 in the process of being formed, and then, as shown in FIG. 4, the next cylindrical gear material 31 is charged into the container 1 and die 2.

Next, the upper bolster 13 of the press is lowered again, and the mandrel 11 of the pressurizing bunch 10 is newly moved to the fire protection 1-
A simple piece (1 inch inside the tooth M surface material 31) is inserted into the marsh 31a and the center hole 32a of the helical gear 32 that is being formed, and the upper bolster 13 is further lowered to pressurize the pressurizing bunch 10. Insert the sleeve 12 into the container 1, lower it roughly, pressurize the top surface of the cylindrical gear material 31 with the bottom surface of the pressure sleeve 12, and press the cylindrical gear material 31 and the helical gear 32 in the process of being formed. A double pressing state is created in which the upper and lower parts are sandwiched between a pressure bunch 10 and a back pressure bunch 21, respectively.

Subsequently, the pressure bunch 10 is lowered with a pressure greater than the pressing force of the back pressure bunch 21, and the unformed portion of the helical gear 32 in the process of being formed is formed into teeth by the tooth forming section 2a of the die 2, and at the same time, the cylinder is Teeth Tj! - The material 31 is sequentially lowered from the tooth profile introduction part 2b of the die 2 to the tooth forming part 2a, and when the lower end of the pressure sleeve 12 reaches a position directly above the tooth profile introduction part 2b of the die 2, both punches 10.21 are removed. make it stop. In this state, the entire outer periphery of the helical gear 32 being processed is formed into a helical shape, and at the same time the cylindrical gear material 31 is formed into a helical shape.
becomes the helical gear 32 that is currently being processed.

Next, immediately after the upper bolster 13 starts to rise, the lower bolster 8 is lowered to the original position where the upper end of the back pressure punch 21 is at the same level as the bottom surface of the spacer 4, as shown in FIG. make it stop. At this time, the formed helical gear 33 is separated from the mandrel 11 as the pressure bunch 10 rises, and is placed on the back pressure bunch 21.

Next, the bushing rod 5 that was waiting inside the spacer 4
is pushed out by a driving means (not shown), and as shown in FIG.
After pushing it out and moving it onto the lower block 6 or dropping it out of the apparatus through the opening 4b, the bushing rod 5 is returned to its original position.

In this way, one helical gear 33 having a center shaft hole 33a as shown in FIG. 7 is formed and taken out from the back pressure bunch 21, and then the back pressure punch 21 is raised and the gear shown in FIG. The cylindrical gear material 31 is brought into contact with the bottom surface of the helical gear 32 which is in the process of being formed, and the next cylindrical gear material 31 is charged into the container 1 and the die 2, resulting in the state shown in FIG.

Subsequently, the pressure bunch 10 is lowered again, and the cylindrical gear material 31 and the helical gear 32 in the process of being formed are both pushed down by the pressure bunch 10 and the back pressure punch 21 above and below them. Thereafter, the steps of forming the teeth of the cylindrical gear material 31 and the helical gear 32 which is in the process of being molded to form the helical gear 33 as shown in FIG. 5 are repeated in the same manner as described above.

(molding example) Next, a specific example of forming a helical gear will be shown below.

The gear extrusion molding device used has the structure shown in FIG. 1, and since each tool double-acts, the main ram that raises and lowers the upper bolster 13 has a capacity of 100 TON, and the lower sub-ram (hydraulic servo) that raises and lowers the bushing rod 23 has a capacity of 100 TON. ) ability is 5
The lower sub-ram, which is incorporated into a 00TON double-acting hydraulic press, can be controlled in its pressurization, forward movement, standby, backward movement, and position by computer control. In addition, since this gear extrusion molding was performed cold, the mantle 11. Pressure sleeve 12. Container 1. The die 2 was made of a carbide material, and the back pressure punch 21 was made of 5KH-9 cold material.

Furthermore, the cylindrical filtration material 31 has an outer diameter of 80 mm.
, inner diameter 39mm.

The ring material was 10 mm thick and was made of 5CR420H (spheroidized annealed material). Furthermore, the target tli
The specifications of car B are in module 1.5. It is a helical gear with a pressure angle of 20'', 45 teeth, and a helical angle of 30'', and the center shaft hole has an inner diameter of 38 mm. The lubricant used was one obtained by applying molybdenum disulfide (MoS2) to the cylindrical gear material 31 and subjecting it to punch treatment (phosphate film treatment).

For extrusion molding, as shown in FIG.
is fixed to the main ram of the press via the upper bolster 13, and the back pressure punch 21 for adding back pressure is attached to the bush rod 23.
It was fixed to the sub-ram under the press through. A dedicated operating program for controlling the position of the back pressure punch 21, pressurization, pressure reduction, back pressure retraction, etc. is created in advance and stored in the computer, so that gear forming work can be performed manually and automatically. The load setting is main ram 700TON.
, 90TON was set in advance.

Next, the forming process was carried out in exactly the same manner as shown in FIGS. 2 to 6, but the tooth profile of the helical gear 33 obtained in this way was completely aligned with the tooth profile of the die 2 in the tooth width direction. A tooth profile similar to the molded part 2b is obtained, which has a high precision comparable to that of a gear cutter, and the front end side surface is formed by the back pressure punch 2.
A flat surface corrected by the tip surface of No. 1 was obtained. - There is a slight crease on the rear end surface, but this is the fate of patch molding and can be removed with a simple finishing process afterwards. The maximum load applied to the pressure punch 10 during molding was measured by attaching a string gauge to the tool, and was about 550 TON, and the maximum load applied to the back pressure punch 21 was also about 85 TON.

Next, when the set load of the back pressure punch 21 was reduced to 300 TON and a similar molding was performed, the front end surface of the obtained helical gear 33 was deformed by the pressure of the back pressure punch 21. Four distinct parts had been formed. In addition, on the contrary, before setting the back pressure punch 21, when "(" was set to 10TON, the tooth profile of the helical gear 33 was incomplete. It was found that there is peace of mind in installing the load.

In addition, in the above-mentioned embodiment and molding example, the case where molding is performed from the southeast side was explained as an example, but by changing the tooth profile shape of the tooth forming part 2a formed inside the die 2, it is possible to Of course, it is also possible to perform complete molding such as teeth, straight teeth), splines, and serrations, and it is also possible to extrude not only those with a circular cross section but also those with an irregular cross section. Moreover, the gear 3 that does not have the center shaft hole 33a
Of course, extrusion molding in step 3 is also possible.

L Effects of the invention As explained above, in the gear extrusion molding method according to the present invention, when a gear having a tooth profile on the outer periphery is carved by extrusion molding, a tooth forming shape corresponding to the tooth profile of the gear to be molded is created. A gear material is placed concentrically on one side in the direction of the central axis of a die, and a pressurizing punch is pushed into one side of the die to press one side of the gear material, and at the same time, one side of the gear material is pressed from the other side of the die. A back pressure punch is pressed against the other surface of the gear material to apply back pressure, and the tooth material is sandwiched between the pressure punch and the back pressure punch and passed through the tooth forming part of the die. As a result, since the tooth profile is molded on the outer periphery of the tooth width material, even when a thin-walled gear is molded by extrusion molding, the gear material does not sag, and therefore the teeth of the molded gear do not bend. Since it is possible to form highly accurate teeth without causing any lack of thickness or warping at the tip, it is possible to form yJl in the post-process! It is possible to significantly reduce the processing cost by processing 1 g, and a very cool effect is brought about in that it is possible to form high precision gears efficiently and at low cost.

[Brief explanation of drawings]

Fig. 1 is an explanatory vertical cross-sectional view of a ceramic chisel head used in carrying out the extrusion molding method for gears according to the present invention; Figs. 2, 3, 4, 5 and 6 are the same as Fig. Fig. 7 is a vertical cross-sectional explanatory diagram showing the length L of extruding gears using the gear extrusion molding equipment shown in Fig. Deep view of gears,
FIG. 8 is an explanatory cross-sectional view showing an example of a conventional Ryokawa extrusion molding apparatus, and FIG. 59 is an explanatory view showing warping and underfilling when the conventional apparatus is used. 2...Die, 2a...Tooth forming part, 10...Pressure punch, 11...Mandrel, 12...Pressure sleeve, 21...Back pressure punch, 21a...Mandrel fitting Matching hole, 31...Gear material, 32...South i in the middle of forming
K, 33...l1iJ car, 33a...shaft hole. Patent applicant Nissan Motor Co., Ltd. Agent Jr. Yutaka Oshio Figure 7/33a Figure 8

Claims (2)

[Claims] (1) A method of molding a gear having a tooth profile on the outer periphery by extrusion molding, in which the gear material is concentrically placed on one side in the central axis direction of a die having a tooth profile corresponding to the tooth profile of the gear to be molded. and press a pressure punch from one side of the die to apply pressure to one side of the gear material, and at the same time press a backpressure punch to the other side of the gear material from the other side of the die to apply back pressure. In addition, the gear forming method is characterized in that the gear material is passed through the tooth forming part of the die in a double-pressed state in which the gear material is sandwiched between the pressure punch and the back pressure punch. (2) The gear to be molded has a shaft hole, a cylindrical gear material is used as the gear material, and the pressure punch has a mandrel and a pressure sleeve concentrically with an outer diameter corresponding to the shaft hole. , the back pressure punch has a fitting hole for the mandrel,
A patent in which the mandrel of the pressure punch and the mandrel fitting hole of the back pressure punch fit together, and the cylindrical gear material is passed through the tooth forming part of the die in a pushed state in which the material is sandwiched between the two punches. A method for extrusion molding a gear according to claim (1).