KR102133458B1 - Manufacture apparatus for hellical gear based on cold forging - Google Patents

Abstract

Cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention, a mold unit for providing a closed space in which the workpiece is compressed for the shape change of the workpiece; A first pressing part disposed on one side of the mold unit to press one surface of the work piece; And a second pressing portion disposed on the other side of the mold unit to press the other surface of the workpiece, wherein the mold unit provides a first space into which the workpiece is inserted by the first pressing portion. Mold unit; And a second mold unit disposed on one side of the first mold unit to provide a second space in which a part of the workpiece inserted in the first space is compressed to deform the shape, and wherein the second mold unit includes: It is disposed in the second space, and when the workpiece is pressed against the second space, it includes a tooth-forming portion forming a tooth on the outer surface of the worksheet, and the tooth-forming portion extends from an upper end to a lower end of the second space It includes a plurality of grooves parallel to each other, and the grooves extend from a top to a bottom with a set twist angle, the thickness of the second mold unit is between 30 mm and 50 mm, and the tooth spacing of the second mold unit is When it is 1.5mm to 4mm, the set angle indicating the direction in which a plurality of grooves formed in the second mold unit extend is characterized in that it is 12 to 24 degrees.

Description

Cold forging-based helical gear precision forming device {MANUFACTURE APPARATUS FOR HELLICAL GEAR BASED ON COLD FORGING}

The present invention relates to a cold forging-based helical gear precision molding apparatus.

In general, gears (gear) can be used in a variety of machinery that requires power transmission or acceleration / deceleration. Recently, as the development of power transmission machinery such as automobiles and ships has been actively developed, the demand for such gears is increasing, and the development of the shape of the workpiece is also developing.

The gear is manufactured in various sizes and shapes and is used in various mechanical parts. In particular, helical gears are more commonly used than general spur gears in recent years.

1 is a perspective view showing the configuration of a helical gear. Referring to FIG. 1, the helical gear 10 constitutes an entire body of a gear, and may include a body part 11 forming an axis and a gear part 12 formed outside the body part to transmit power. have. For example, the body portion 11 may be a cylindrical shape, or a ring shape in which a void is formed inside.

The gear portion 12 is formed on the outside of the body portion 11, it can be bent at a certain angle from the axial direction. For example, when the main body portion 11 is a cylinder, several teeth 13 in a shape inclined at a predetermined angle along the outer wall from the upper side to the lower side of the main body portion 11 may be formed.

The helical gear is widely used because it has a better bite rate than a general spur gear, and thus has excellent power transmission effect and low noise generated during rotation. However, the helical gear has a disadvantage in that the manufacturing process is more difficult than that of a general spur gear as the toothed stem is bent at a certain angle from the axial direction of the gear.

Conventionally, after manufacturing a work piece, a helical gear was manufactured through a cutting process of cutting and processing a tooth shape of a helical gear outside.

Prior literature on such a conventional cold forging based helical gear precision molding apparatus or manufacturing method is as follows.

[Advanced technical literature]

[Patent Document]

Domestic application number 10-2012-0137376 (published date: November 26, 2013, title of invention: a tool for cutting gears and a method for cutting gears)

The cutting process for manufacturing a conventional helical gear has the following problems.

First, there is a problem in that the spacing between the gears of the helical gear and the height of the teeth are not evenly formed. That is, since it is a process of cutting a metal material into its shape by using a cutting machine, if there is a slight external impact such as shaking in the cutting process, the teeth of the helical gear cannot be formed evenly, and there is a problem that meshing between gears is not properly performed. have.

Second, in the case of the cutting process, the cutting process for cutting the gear is complicated, and in order to manufacture a single helical gear, dozens of teeth have to be cut, so there is a disadvantage in that manufacturing time and manufacturing cost are high.

Third, after the helical gear is manufactured through the cutting process, a post-process is required for the helical gear to operate normally, but this post-process step takes a long time and is expensive.

Accordingly, recently, a device or method for manufacturing a helical gear using a cold forging method has been developed. The cold forging method is a process of forming a desired shape by compressing a work piece at a temperature below normal temperature or recrystallization temperature, and improving the structure and molding.

In the case of such a cold forging method, it is possible to improve the mechanical properties of a material to be produced by compressing a metal material compared to cutting, thereby changing the shape, and also has an advantage of high economic efficiency by reducing waste of raw materials. However, the conventional cold forging method has the following problems.

First, as a material having a desired shape is manufactured by compressing a workpiece in a mold, there is a problem in that the durability of the mold decreases in a short time.

Second, as the durability of the mold decreases in a short period of time, there is a problem in that the manufacturing cost of the mold increases, which increases the manufacturing cost.

Third, there is a problem in that it takes a long time to manufacture a desired shape through one mold.

In order to solve the above problems, an object of the present invention is to provide a cold forging-based helical gear precision molding apparatus using a cold forging method rather than cutting.

Cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention, a mold unit for providing a closed space in which the workpiece is compressed for the shape change of the workpiece; A first pressing part disposed on one side of the mold unit to press one surface of the work piece; And a second pressing portion disposed on the other side of the mold unit to press the other surface of the workpiece, wherein the mold unit provides a first space into which the workpiece is inserted by the first pressing portion. Mold unit; And a second mold unit disposed on one side of the first mold unit to provide a second space in which a part of the workpiece inserted in the first space is compressed to deform the shape, and wherein the second mold unit includes: It is disposed in the second space, and when the workpiece is pressed against the second space, it includes a tooth-forming portion forming a tooth on the outer surface of the worksheet, and the tooth-forming portion extends from an upper end to a lower end of the second space It includes a plurality of grooves parallel to each other, and the grooves extend from a top to a bottom with a set twist angle, the thickness of the second mold unit is between 30 mm and 50 mm, and the tooth spacing of the second mold unit is When it is 1.5mm to 4mm, the set angle indicating the direction in which a plurality of grooves formed in the second mold unit extend is characterized in that it is 12 to 24 degrees.

The cold forging-based helical gear precision molding apparatus according to the embodiment of the present invention constituting the above configuration has the following effects.

First, the teeth of the helical gear are evenly formed, thereby reducing the cost and time required for the post-process.

Second, since the strength of the metal material used for manufacturing the helical gear is sensed and pressurized at an appropriate pressure, the durability of the mold used is increased, and accordingly, the mold manufacturing cost is reduced.

Third, as the process for manufacturing one helical gear is divided into multiple stages and manufactured using a plurality of molds, manufacturing time is reduced and durability of the molds is improved.

1 is a perspective view showing the configuration of a helical gear
Figure 2 is a perspective view of a helical gear manufacturing unit of a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention
Figure 3 is a perspective view of the cold forging-based helical gear precision molding device of the helical gear manufacturing unit of the mold unit separated
Figure 4 is a side sectional view of the helical gear manufacturing unit of the configuration of the cold forging-based helical gear precision molding device
5 is a view showing a step of manufacturing a helical gear with a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention
6 is a flow chart of a method for manufacturing a helical gear through a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention
7 is a side sectional view of a second mold unit in the configuration of the helical gear manufacturing unit

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented in many different forms and is not limited to the structures or methods described herein.

Figure 2 is a perspective view of a helical gear manufacturing unit of a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention, Figure 3 is a cold forging-based helical gear precision molding apparatus configuration of the helical gear manufacturing unit of the mold separation One perspective view, Figure 4 is a side sectional view of the helical gear manufacturing unit of the configuration of the cold forging-based helical gear precision molding apparatus.

2 to 4, the mold unit of the helical gear according to the embodiment of the present invention, may include a first pressing portion 200 and a second pressing portion 300.

The mold unit is a means for providing a space in which the workpiece 20 is inserted and compressed. In detail, the mold unit may include a first mold unit 110 and a second mold unit 120. Below, the first mold unit 110 is disposed under the second mold unit 120, and the first pressing unit 200 is disposed above the first mold unit 110 and the first 2 The pressing part 300 is prepared based on what is disposed under the second mold unit 120, but is not limited thereto, and the second mold unit 120 is located at the bottom of the first mold unit 110. Note that it can be applied even if deployed.

The first mold unit 110 is a portion into which a metal material (hereinafter, a work piece 20), which is a raw material for forming a helical gear, is inserted. In detail, the first mold unit 110 is the second mold unit. Arranged on the upper side of the 120, the workpiece 20 can be inserted to maintain the state before the primary processing.

In addition, the workpiece 20 may have a hollow formed therein with respect to the axial direction. That is, the work piece 20 may have a cylindrical shape with an inside pierced in the axial direction.

The first mold unit 110 includes a first mold body 112 in which the work piece 20 is inserted, and a first space 111 through which the first pressing part 200 reciprocates is formed, Arranged in the first space 111, the seating portion 113 on which the work piece 20 can be seated, and the outer side of the first mold body 112 to protect the first mold body 112 It may include a first housing surrounding the.

In detail, the first space 111 may have a hollow shape inside the first mold body 112 along the axial direction of the first mold body 112. The first seating portion 113 may be formed on one side of the first space 111, in which case the first pressing portion 200 may reciprocate through the other side of the first space 111. Can.

In addition, the first seating portion 113 may have a size of a diameter that does not swing from side to side at the same time as the workpiece 20 is inserted and seated.

The first pressing part 200 is disposed on the upper side of the first mold unit 110 and is a means for pressing the work piece 20 seated on the first mold unit 110. In detail, the first pressing unit 200 may move downward from the upper side of the first mold unit 110 to press one surface of the workpiece 20 downward. When the first pressing part 200 presses one surface of the work piece 20, the work piece 20 rotates and can be inserted into the first mold unit 110 and the second mold unit 120. have.

In addition, the first pressing part 200 may rotate in the first space 111 and press the work piece 20, in which case the work piece 20 is the first pressing part 200 It can be inserted into the first mold unit 110 and the second mold unit 120 while rotating along the rotation direction of the.

In detail, the first pressing part 200 is in contact with the first inserting part 210 inserted into the hollow of the work piece 20 and one surface of the work piece 20 to press the work piece 20 It may include a first contact portion 220. However, when the hollow is not formed in the first inserting part 210, the workpiece 20 may be omitted.

The first insertion portion 210 is a portion that is formed into the same diameter as the hollow of the workpiece 20 and is inserted into the workpiece 20. When the first pressing part 200 presses one surface of the work piece 20, the first inserting part 210 is inserted into the hollow of the work piece 20, so that the work piece 20 is It has the effect of preventing vibration or shaking.

The first contact portion 220 is formed with a larger diameter than the first insertion portion 210 is a means to press one surface of the workpiece 20. In detail, the first contact portion 220 may have a diameter between the diameter of the first seating portion 113 and the diameter of the hollow of the workpiece 20, and thus inserted into the first seating portion 113 However, it is possible to press one surface of the workpiece 20 without being inserted into the hollow of the workpiece 20.

The second mold unit 120 is disposed in the second mold body 122 and the second space 121 in which the second space 121 through which the second pressing part 300 reciprocates is formed. The second mold body 122 to protect the second mold body 122 and the tooth forming part 123 having a shape corresponding to a tooth shape to be formed on the outside of the workpiece 20 and formed inside. ) May include a second housing surrounding the outside.

In detail, the second space 121 may be a hollow formed along the axial direction of the second mold body 122. The second pressing part 300 may reciprocate to press the work piece 20 through the second space 121.

In more detail, when the work piece 20 is disposed on the seating portion 113, the first pressing part 200 contacts the one surface of the work piece 20 and rotates the work piece 20 while rotating. It can be pressed to one side. In this case, the workpiece 20 is inserted into the first space 111 and the second space 121 of the mold unit while rotating together in the same direction as the rotation direction of the first pressing part 200, and the A part of the work piece 20, that is, a part for forming a tooth may be inserted into the tooth forming part 123 formed in the second space 121. Accordingly, a tooth shape corresponding to the inner shape of the tooth forming portion 123 may be formed outside the part of the inserted work piece 20.

In addition, the tooth forming unit 123 may be formed differently according to the manufacturing steps of a plurality of helical gear manufacturing units of a cold forging-based helical gear precision molding apparatus to be described later. Details will be described later.

In the above embodiment, the mold unit is described as being separated into the first mold unit 110 and the second mold unit 120, but is not limited thereto, and the first mold unit 110 and the second mold unit ( 120) may be integrally formed to form the mold unit, and the vertical direction of the first mold unit 110 and the second mold unit 120 may also be changed from each other.

The second pressing part 300 is disposed on the lower side of the second mold unit 120, seated on the first mold unit 110 and the workpiece formed with the teeth by the second mold unit 120 It is a means to press (20) to the other side opposite to one side. For example, the second pressing unit 300 may move upward from the lower side of the second mold unit 120 to press the other surface of the workpiece 20 upward.

The second pressing part 300 extends from the second contacting part 310 and the second contacting part 310 contacting the other surface of the work piece 20 to pressurize the work piece 20, and the second contacting part It may include a second insert to support 310 and reciprocally move the second space 121 of the second mold body 122.

When the second contact part 310 presses the other surface of the work piece 20, the work piece 20 fitted to the tooth forming part 123 and having a tooth formed outside may move upward. In this case, the work piece 20 may be separated from the tooth forming part 123 while the teeth formed on the outside of the work piece 20 are further refined.

The helical gear manufacturing unit according to an embodiment of the present invention is connected to the first pressing part 200 and when the first pressing part 200 first presses the work piece 20, the work piece 20 For the plastic deformation of the sensor unit 230 and the first pressure value measured by the sensor unit 230 to measure the first pressure value applied to the workpiece by the first pressing unit 200 The operation of the first pressing portion 200 and the second pressing portion 300 so that the first pressing portion 200 and the second pressing portion 300 can press the workpiece 20 as a reference It may further include a control unit for controlling the.

In detail, the sensor unit 230 may measure the first pressure value for the workpiece 20 to cause plastic deformation when the first pressing unit 200 performs test pressing. In order to determine the plastic deformation point, an additional sensing module may be further included in the groove of the mold to check whether the workpiece penetrates the mold groove. That is, when the sensing module in the mold groove detects that the workpiece causes plastic deformation due to the pressure of the first pressing part and enters the groove of the mold, the time point is determined as the plastic deformation time point, and the 1 The pressure of the pressing unit 200 may be set as the first pressure value.

That is, the first pressure value may be a minimum stress value for the workpiece 20 to cause plastic deformation.

In the control unit, when the sensor unit 230 measures the first pressure value, the first pressurization unit 200 and the second pressurization unit 300 perform the work at a constant pressure value based on the first pressure value. The operation of the first pressing part 200 and the second pressing part 300 may be controlled to press the piece 20.

For example, when the first pressure value is 5 Pa, the control unit may adjust the pressing force values of the first pressing part 200 and the second pressing part 300 with a force of 6 to 8 Pa, and accordingly The first pressing part 200 and the second pressing part 300 may press the workpiece 20 with the adjusted pressing force value. This may be a pressure value at which the workpiece 20 is not damaged and at the same time the mold unit is not damaged, which is weaker, equally or stronger than the first pressure value as the user sets it. And the second pressing part 300 may press the work piece 20.

Table 1 is data for measuring the helical gear defect rate produced by differently varying the second pressure value in order to confirm a correlation between the first pressure value and the second pressure value.

1st pressure value Second pressure value Gear defective rate 100GPa 90GPa 92.7% 100GPa 100GPa 31.1% 100GPa 110GPa 3.2% 100GPa 120GPa 2.4% 100GPa 130GPa 3.1% 100GPa 140GPa 14.5% 200GPa 180GPa 96.8% 200GPa 200GPa 34.8% 200GPa 220GPa 4.5% 200GPa 240GPa 2.2% 200GPa 260GPa 3.6% 200GPa 280 GPa 17.9%

Referring to Table 2, experiments were performed by dividing the first pressure values of 100 GPa and 200 GPa.

When the first pressure value was 100 GPa, the second pressure value was lower than 100 GPa, and most of the defects occurred. In the same case, 31.1% of defects occurred. From 110 GPa to 130 GPa, the defective rate was less than 4%, but at 140 GPa, it was measured as 14.5%, and the moment the 30 GPa exceeded the first pressure value, the defective rate of the helical gear was high. It is thought that the helical gear was damaged by excessive force.

Likewise, when the first pressure value was 200 GPa, most of the failure occurred when the second pressure value was lower than 200 GPa, and 34.8% of failure occurred in the same case. From 220 GPa to 260 GPa, the defective rate was less than 5%, but at 280 GPa, it was measured as 17.9%, and the moment the 80 GPa exceeded the first pressure value, the defective rate of the helical gear was high. It is thought that the helical gear was damaged by excessive force.

Through the above experiment, when the second pressure value is 110% to 130% of the first pressure value, it was confirmed that the gear generation efficiency is the highest.

Hereinafter, a cold forging-based helical gear precision molding apparatus for manufacturing the workpiece 20 as the helical gear will be described.

The cold forging-based helical gear precision molding apparatus may include one or more helical gear manufacturing units.

In detail, the cold forging-based helical gear precision molding apparatus may include a plurality of helical gear manufacturing units to manufacture the workpiece 20 as helical gears of various shapes, in which case the workpiece ( 20) is a step-by-step shape is manufactured by a plurality of the helical gear manufacturing unit may be finally manufactured as a helical gear required by the user.

The cold forging-based helical gear precision molding apparatus in the embodiment below may include six helical gear manufacturing units. However, this is only an example, and it is revealed that the number of helical gear manufacturing units may vary depending on the shape of the helical gear to be manufactured.

5 is a view showing a step of manufacturing a helical gear with a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention, Figure 6 is a cold forging-based helical gear precision molding apparatus according to an embodiment of the present invention It is a flow chart of the helical gear manufacturing method.

Referring to FIG. 5, the cold forging-based helical gear precision molding apparatus may include first to sixth helical gear manufacturing units.

Referring to FIG. 6, the helical gear manufacturing method includes a material processing step (S110), a body part manufacturing step (S120), a gear part manufacturing step (S130), a hollow forming step (S140), and a body part tooth forming step (S150). ) And a gear tooth forming step (S160 ). Hereinafter, a method of manufacturing the helical gear through the cold forging-based helical gear precision molding apparatus will be described in detail.

In detail, the material processing step (S110) may be a step of manufacturing a work piece 20 for manufacturing a metal material for manufacturing the helical gear as the helical gear.

In more detail, in the material processing step (S110), the user may be a step of cutting the metal material, preferably a bar-shaped metal material to a predetermined length to manufacture the helical gear, and processing the workpiece 20. have. Through the material processing step (S110), a cylindrical workpiece 20 for manufacturing the helical gear may be manufactured.

The main body manufacturing step (S120) may be a step of manufacturing the main body part among the helical gears. In detail, in the main body manufacturing step (S120), a first helical gear manufacturing unit and a second helical gear manufacturing unit of the cold forging-based helical gear precision molding apparatus may be used.

The first space 1111 of the first mold unit 1110 of the first helical gear manufacturing unit may be a cylindrical shape into which the workpiece 20 can be inserted, and a second space of the second mold unit 1120. The second space 1121 may be a cylindrical shape having a diameter smaller than the diameter of the workpiece 20 by the teeth forming portion 1123 disposed at 1112.

The workpiece 20 manufactured through the material processing step S110 may be inserted into the first space 1111, and the first pressing portion 1200 of the first helical gear manufacturing unit may be the workpiece. As the one surface of 20 is pressed, it may be pressed in the direction of the second space 1121 in which the teeth forming portion 1123 is formed. Accordingly, a part of the workpiece 20 is rotated and inserted into the second space 1121, and at the same time, a portion having a smaller diameter can be generated by the tooth forming part 1123. A portion of the workpiece 20 having a reduced diameter may be defined as a body portion, whereby the body portion manufacturing step S120 may be completed.

In detail, the main body portion 21 may be manufactured by the first helical gear manufacturing unit, but in the embodiment, the main body portion by the second helical gear manufacturing unit, the first body portion 21 and the second body portion ( 22) to prepare a helical gear. The first body portion 21 is a body portion portion generated by the first helical gear manufacturing unit, and the second body portion 22 is a body portion portion generated by the second helical gear manufacturing unit.

The first mold unit 2110 of the second helical gear manufacturing unit is the same as the first mold unit 1110 of the first helical gear manufacturing unit, and the second mold unit 2120 is the first helical gear manufacturing unit The same shape as the second mold unit 1120, but the second space 2121 is larger than the diameter of the second space 1121 of the first helical gear manufacturing unit and the first of the first mold unit 2110. It may be formed smaller than the diameter of the space 2111.

Accordingly, the diameter of the second body portion 22 may be larger than the diameter of the first body portion 21 and smaller than the diameter of the gear portion 23 to be described later.

The gear part manufacturing step (S130) is a step of manufacturing a gear part 23 in which the teeth of the helical gear of the work piece 20 are to be formed on the outside. In the gear part manufacturing step (S130), a third helical gear manufacturing unit of the cold forging-based helical gear precision molding apparatus may be used.

The third helical gear manufacturing unit may have a shape in which the second mold unit 3120 is disposed above the first mold unit 3110. That is, the workpiece 20 may have a shape that is inserted from the lower side through the first mold unit 3110 of the third helical gear manufacturing unit. In detail, the gear portion 23 of the workpiece 20 may be inserted from the lower side through the first space 3111 of the first mold unit 3110.

In this case, the first pressing unit 3200 of the third helical gear manufacturing unit is below the first mold unit 3110, and the second pressing unit 3300 is above the second mold unit 3120. Can be deployed. When the gear portion 23 of the workpiece 20 is inserted into the first space 3111 of the first mold unit 3110, the other surface of the workpiece 20 while the first pressing portion 3200 rotates By pressing and, while the workpiece 20 is rotated, the gear portion 23 may be formed by being inserted into the tooth forming portion 3123 of the second mold unit 3120.

The hollow forming step (S140) is a step in which a hollow is formed in the gear portion 23 of the workpiece 20, thereby forming a groove in which the helical gear is coupled to the outside. In the hollow forming step (S140), a fourth helical gear manufacturing unit of the cold forging-based helical gear precision molding apparatus may be used.

The fourth helical gear manufacturing unit may have a shape in which the second mold unit 4120 is disposed below the first mold unit 4110. In detail, the gear part 23 of the workpiece 20 may be inserted from the upper side through the first space 4111 of the first mold unit 4110.

When the gear portion 23 of the workpiece 20 is disposed in the second space 4121 of the second mold unit 4120 through the first space 4111 of the first mold unit 4110, the first pressing part 4200 may press one surface of the workpiece 20, that is, the gear portion 23 downward. In this case, the first insertion portion 4210 of the first pressing portion 4200 presses one surface of the gear portion 23 on one surface of the gear portion 23 supported by the second mold unit 4120. While hollow may be formed in the gear portion (23).

The tooth forming step (S150) of the main body is a step of forming a screw-shaped tooth on the body portion of the workpiece 20 so that a nut or the like can be later coupled to the helical gear. In the tooth forming step (S150) of the main body, a fifth helical gear manufacturing unit may be used.

In the fifth helical gear manufacturing unit, a first mold unit 5110 may be disposed under the second mold unit 5120. In addition, the teeth forming portion 5123 disposed in the second space 5121 of the second mold unit 5120 may be formed with a number of parallel threads extending laterally.

When the main body parts 21 and 22 of the work piece 20 are inserted into the first space 5111 of the first mold unit 5110, the first pressing part 5200 of the work piece 20 The portion of the main body portion 22 may be pressed by pressing the gear portion 23 to be inserted into the second space 5121 of the second mold unit 5120. In this case, a parallel thread-shaped tooth may be formed in a part of the body portion 22 of the workpiece 20 by the tooth forming portion 5123 formed in the second space 5121.

The gear tooth forming step (S160) is a step of forming a helical gear thread by forming a spiral tooth on the gear portion 23 of the workpiece 20. In the gear tooth forming step (S160), a sixth helical gear manufacturing unit may be used.

In the sixth helical gear manufacturing unit, the first mold unit 6110 may be disposed under the second mold unit 6120. In addition, the teeth forming portion 123 disposed in the second space 6121 of the second mold unit 6120 may include a plurality of grooves extending from the top of the second space 6121 to the bottom. In this case, the plurality of grooves may have a spiral shape with a set angle or set curvature. In detail, the set angle of the helical gear means the gear twist angle of the helical gear.

7 is a side cross-sectional view of the second mold unit 120 of the configuration of the helical gear manufacturing unit.

Referring to FIG. 7, the tooth-forming part 123 having a groove for forming a helical gear in the second mold unit, passes through the front area A1 and the front area A1 through which the initial workpiece enters. It can be divided into a rear area (A2).

At this time, the angle (hereinafter, set angle α) of the teeth for forming the helical gear in the work piece in the rear area A2 may be 10° to 20°.

That is, the set angle α may be an angle forming the center of the helical gear formed on the workpiece, and the helical gear formed with the set angle α may be connected to another gear to transmit power.

Hereinafter, first, the setting angle α of the tooth forming portion 123 of the rear area A2 for forming an effective helical gear and the tooth spacing will be described.

Below, we confirm the results of experiments on how the durability of the mold changes depending on the set angle (α).

Table 2 is data confirming the number of helical gears taken until the mold is damaged for each angle of the set angle α.

Mold thickness Tooth spacing Setting angle (α) Helical Gear Production 30 mm 1 mm 9° 8,210 30 mm 1 mm 12° 12,019 30 mm 1 mm 15° 12,954 30 mm 1 mm 20° 11,593 30 mm 1 mm 25° 10,026 30 mm 1 mm 28° 8,853 30 mm 2 mm 9° 9,896 30 mm 2 mm 12° 13,017 30 mm 2 mm 15° 13,852 30 mm 2 mm 20° 12,793 30 mm 2 mm 25° 10,026 30 mm 2 mm 28° 9,124 50 mm 4 mm 9° 11,017 50 mm 4 mm 12° 16,158 50 mm 4 mm 15° 17,971 50 mm 4 mm 20° 17,024 50 mm 4 mm 25° 13,220 50 mm 4 mm 28° 11,845

Referring to Table 1, the second mold was measured using three types. The first type is a mold unit with a mold thickness of 30 mm and a tooth spacing of 1.5 mm, the second type is a mold unit with a mold thickness of 30 mm and a tooth spacing of 2 mm, and the third type is a mold unit with a mold thickness of 500 mm and a tooth spacing of 4 mm. .

Here, the mold thickness of the second mold is a vertical length of the tooth forming portion for forming the helical gear, and it was previously confirmed that the optimum yield is exhibited when it is between 30 mm and 50 mm through experiments.

In detail, the second mold unit is a mold for forming a helical gear through restraint molding, one end of the tooth-forming part is an opening for the work piece to enter, and the other end is a closed structure to prevent the work piece from entering the work piece. Is that it enters through the opening and is blocked by the closing part, and then expands to the groove side of the tooth forming part of the mold by a force applied vertically to form a helical gear.

In order to form the concentricity angle between the shaft of the gear shaft of the helical gear and the gear formed in the second mold unit for constrained molding close to vertical (at least 0.2° or less), the length of the tooth forming portion of the second mold unit, That is, the mold thickness should be 30 mm to 50 mm. More preferably, it was confirmed through experiments that the thickness of the second mold unit was between 38 mm and 45 mm in order to maintain the concentricity angle within 0.1°.

Next, in these three mold units, the set angle (α) is set to five angles of 9°, 12°, 15°, 20°, 25°, and 28°, respectively, and the mold may be damaged through the mold unit. The number of helical gear production until then was measured. In the first type of mold unit, when the set angle (α) was 9° and 28°, it was confirmed that less than 10,000 helical gears were produced, and the set angle (α) was In the case of 12°, the number of helical gear production increased rapidly, and it was confirmed that the number of helical gear production rapidly decreased while the set angle (α) exceeded 24°.

In the second type of mold unit, it was confirmed that less than 10,000 helical gears are produced when the set angle (α) is 9° and 28°, and when the set angle (α) is 12°, the number of helical gear production increases rapidly. However, it was confirmed that the set angle (α) exceeds 24°, and the number of helical gear production decreases rapidly.

In the third type of mold unit, it was confirmed that less than 12,000 helical gears are produced when the set angle (α) is 9° and 28°, and when the set angle (α) is 12°, the number of helical gear production increases rapidly. However, it was confirmed that the set angle (α) exceeds 24°, and the number of helical gear production decreases rapidly.

Through this, when the set angle (α) of the plurality of grooves of the teeth forming portion 123 in the mold unit is 12 ° to 24 °, it was confirmed that the durability of the mold is the strongest. And more preferably, when the set angle (α) of the plurality of grooves is 14 ° to 22 °, it was confirmed that the durability of the mold is most improved to show the optimum yield. And most preferably, when the set angle (α) of the plurality of grooves is 18 ° to 20 °, it was confirmed that the durability of the mold is most improved to show the optimum yield.

Accordingly, in an embodiment, the set angles of the front region A1 and the rear region A2 of the second mold unit 1230 may be 18° to 20°.

In the tooth forming step of the gear portion (S160), when the gear portion 23 of the workpiece 20 is inserted into the first space 111 of the first mold unit 110, the first pressing portion 200 is The gear part 23 of the work piece 20 may be pressed to press the gear part 23 to be inserted into the second space 121 of the second mold unit 120. In this case, a tooth shape having a shape corresponding to the plurality of grooves may be formed on the outer surface of the gear portion 23 by the tooth forming portion 123 formed in the second space 121.

However, when the angle of the groove forming the tooth forming portion 123 in the front region A1 of the second mold unit 1230 is a set angle α, an excessive impact is applied to the workpiece from the beginning and the principle of action reaction In addition, the groove of the second mold unit may be excessively impacted to damage the mold.

In another embodiment, in order to overcome this, the angle β of the groove of the front region A1 of the second mold unit may be formed smaller than the set angle α of the rear region A2.

Through the experiment, it was found that the initial groove angle among the angles of the grooves in the front region A1 should be less than 8°. When the initial groove angle of the front region A1 was set to 8° or more, the direct damage to the coating of the teeth forming portion 123 of the initial mold by the work piece could be immediately visually confirmed.

Preferably, the initial groove angle among the angles β of the grooves in the front region A1 can be confirmed through an experiment that is greater than 4° and less than 6°. Because, when the initial groove angle of the tooth forming portion 123 is set to 4° or less, the front region A1 up to the back region A2 of the tooth forming portion 123 formed at the set angle α is reached. This is because there is a problem that the size increases and the effective area (the area where the gear of the set angle α is formed) among the helical gears of the workpiece decreases. In addition, when the initial groove angle of the tooth forming portion 123 is set to 6° or more, there is a problem in that the yield is rapidly reduced by excessively impacting the initial entry groove of the tooth forming portion 123 of the mold.

Next, the initial groove angle of the front region A1 gradually increases, so that the groove angle β at the last rear end can achieve a set angle α.

That is, the initial groove angle of the front region A1 is greater than 4° and less than 6°, and the groove angle β increases linearly so that the groove angle at the rear end is a set angle α (for example, more than 14° 16 ° below).

On the other hand, in order to further reduce the impact applied to the grooves of the workpiece and the tooth-forming portion 123, the groove depth (hereinafter referred to as the tooth spacing) of the tooth-forming portion 123 of the front region A1 is the rear region A2. It may be formed shallower than the depth of the groove of the teeth forming portion 123. Here, the groove depth of the tooth forming portion 123 may mean a height obtained by combining the height of the tooth tip and the root of the tooth.

That is, the tooth spacing of the tooth forming portion 123 of the front region A1 of the second mold unit may be smaller than the tooth spacing of the tooth forming portion of the rear region A2.

Likewise, the tooth spacing, which is the initial groove depth of the tooth forming portion 123 of the front region A1 converges to almost 0, and then increases in depth at a certain slope at one point, so that the tooth spacing, which is the rear groove depth, is the rear region A2. ) Can reach the set tooth spacing (1.5mm to 4mm).

For example, in an embodiment, the initial groove depth of the tooth-forming portion 123 is formed to be 0,5 mm to 1.2 mm, buffering the entry of the tooth-forming portion 123 of the workpiece, and 8° to 12° at one point As the depth increases, the groove depth may be formed in the rear region A2 at a preset tooth spacing of 4 mm.

In summary, the front region A1 of the tooth forming portion 123 of the second mold unit is an area for smoothly entering the workpiece into the tooth forming portion 123, and as much impact as possible on the coating of the workpiece and the mold groove. In order to alleviate the depth of the initial groove, it is formed smaller than the set tooth depth, and the groove depth is increased at a constant angle in the rear end region of the front region A1 to set the rear region A2 at the rear end of the front region A1. The tooth gap can be reached.

Further, in another embodiment, the front region A1 of the tooth forming portion 123 of the second mold unit is an area for smoothly entering the workpiece into the tooth forming portion 123, and the To alleviate the impact on the coating as much as possible, the angle of the groove in the front region (A1) and the tooth spacing gradually increase, and the angle of the groove in the rear stage and the tooth spacing, the angle of the groove in the rear region (A2) to form an effective helical gear. It can be equal to the phosphorus setting angle (α) and tooth spacing.

Furthermore, a special coating may be added to the tooth forming portion 123 to reduce impact and enter the workpiece into the groove.

In detail, the special coating may be a coating agent containing at least two or more elements of Al, Cr, Ti and CN.

In particular, since the coating of the tooth-forming part of the front region A1 is a key point for determining the life of the mold, it can be a second special coating agent having elasticity and high rigidity to flexibly accept the entry of the workpiece, regardless of cost. have.

The second special coating agent may be a coating agent including all of Al, Cr, Ti, and CN.

However, since the second special coating agent is expensive and has high elasticity, it may not be suitable for forming an effective helical gear. Therefore, the coating of the teeth forming part of the rear region A2 is the first special coating agent, and the elastic force is higher than that of the second special coating agent. It can be relatively low.

In detail, the second special coating agent is a TiN coating, which has a lower elasticity than the first special coating agent, but has higher strength, so that the helical gear can be accurately formed at a set angle (α) and a set tooth spacing.

The cold forging-based helical gear precision forming apparatus having the above-described configuration can not only save the manufacturing time and manufacturing cost of the helical gear by manufacturing the helical gear at each stage through a plurality of helical gear manufacturing units. There is an effect that can increase the durability of the mold by adjusting the angle (α).

Claims (7)

A mold unit that provides a closed space in which the work piece is compressed to change the shape of the work piece;
A first pressing part disposed on one side of the mold unit to press one surface of the work piece; And
It is disposed on the other side of the mold unit includes a second pressing portion for pressing the other surface of the workpiece,
The mold unit may include: a first mold unit providing a first space into which the workpiece is inserted by the first pressing unit; And a second mold unit disposed on one side of the first mold unit to provide a second space in which a part of the workpiece inserted in the first space is compressed to deform the shape,
The second mold unit includes a tooth-forming portion disposed in the second space to form teeth on the outer surface of the workpiece when the workpiece is pressed into the second space,
The tooth-forming portion includes a plurality of grooves extending from the top to the bottom of the second space and parallel to each other, and the grooves extend from the top to the bottom with a set twist angle,
The tooth forming unit is divided into a front region into which the initial workpiece enters, and a rear region forming a tooth having an effective tooth spacing and an effective set angle on the workpiece,
When the thickness of the second mold unit is between 30 mm and 50 mm, and the effective tooth spacing of the tooth forming portion is 1.5 mm to 4 mm, the effective setting angle indicating a direction in which a plurality of grooves of the tooth forming portion extend is 12 Characterized in that the degree to 24 degrees,
The set angle of the initial groove in the front area is less than 8 degrees, and the set angle of the groove in the front area gradually increases so that the set angle of the groove at the rear end of the front area converges to the effective set angle,
The tooth spacing of the initial groove in the front region is formed smaller than the tooth spacing of the groove in the rear region, and the tooth spacing of the groove in the front region gradually increases so that the tooth spacing of the groove in the rear end converges to the effective tooth spacing,
The depth of the initial groove in the front region is formed between 0.5 mm and 1.2 mm, and the depth of the groove in the front region gradually increases so that the depth of the groove at the rear end of the front region converges to the depth of the groove in the rear region. and,
A sensor unit for measuring a pressure value when the first pressing unit presses the work piece, and a control unit controlling an operation of the first pressing unit and the second pressing unit based on the pressure value measured by the sensor unit. Including more,
When the pressure value measured by the sensor unit after operating the first pressing unit is measured as the first pressure value that is the minimum stress value that causes plastic deformation of the workpiece, the control unit may include the first pressing unit and the second pressing unit. By further controlling the pressing portion to adjust the pressure value applied to the workpiece according to the measured first pressure value,
The sensor portion is disposed on the side of the first insertion portion that is inserted into the hollow of the workpiece in the first pressing portion,
It is disposed in the groove of the mold unit further comprises an additional sensing module for detecting whether the workpiece has penetrated into the groove,
The control unit controls the second pressing unit to apply a second pressure value between 110% and 130% of the first pressure value measured by the sensor unit to the workpiece,
The front region of the tooth-forming part is coated with a first coating agent containing at least two or more elements of Al, Cr, Ti, C and N,
The rear region of the tooth-forming part is coated with a second coating agent including Al, Cr, Ti, C and N.
Cold forging based helical gear precision forming device. According to claim 1,
The effective set angle indicating the direction in which the plurality of grooves formed in the second mold unit extends is 14 to 22 degrees.
Cold forging based helical gear precision forming device. According to claim 1,
The effective setting angle indicating the direction in which a plurality of grooves formed in the second mold unit extend is 20 degrees.
Cold forging based helical gear precision forming device. delete delete delete delete

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