KR102074458B1 - Multistage Cold Former for Manufacturing Helical Gear - Google Patents

Abstract

According to one embodiment of the present invention, a multi-stage cold former for manufacturing a helical gear comprises a plurality of manufacturing units including a mold unit and a plurality of pressurization units to form a workpiece. The multi-stage cold former comprises: a first manufacturing unit for manufacturing a main body unit of the helical gear; a second manufacturing unit for manufacturing a gear unit of the helical gear; a third manufacturing unit for forming a groove or a hollow on the main body unit; a fourth manufacturing unit for forming a first screw thread on the main body unit; and a fifth manufacturing unit for forming a second screw thread on the gear unit. The second screw thread is formed in a shape having a torsion setting angle from the top to the bottom of the gear unit.

Description

Multistage Cold Former for Manufacturing Helical Gear

The present invention relates to a multi-stage cold former for helical gear manufacturing.

In general, gears can be used in a variety of applications that require power transmission or acceleration / deceleration. Recently, as the development of power transmission machinery such as automobiles and ships is actively made, the demand for such gears increases, and the shape of the workpiece is also developing.

The gears are manufactured in various sizes and shapes and used for various mechanical parts. In particular, helical gears are used more recently than general spur gears.

1 is a perspective view showing the configuration of a helical gear. Referring to FIG. 1, the helical gear 10 may include a main body 11 forming an entire body of a gear, forming a shaft, and a gear 12 formed outside the main body to transmit power. have. For example, the main body 11 may have a cylindrical shape or a ring shape having a cavity formed therein.

The gear part 12 may be formed outside the main body part 11 to be bent at an angle from the axial direction. For example, when the main body 11 is a cylinder, a plurality of teeth 13 inclined at an angle along the outer wall from the upper side to the lower side of the main body 11 may be formed.

 The helical gears are widely used because they have a better bite rate than general spur gears, so that the power transmission effect is excellent and the noise generated during rotation is also small. However, the helical gear has a disadvantage in that the manufacturing process is more difficult than the general spur gear as the tooth stem is manufactured to be bent at an angle from the axial direction of the gear.

Conventionally, after manufacturing a workpiece (Work Piece), a helical gear was manufactured through a cutting process of cutting and processing the teeth of the helical gear on the outside thereof.

Prior art for a multi-stage cold former or a manufacturing method for manufacturing such a conventional helical gear is as follows.

[Preceding technical literature]

[Patent Documents]

Domestic Application No. 10-2012-0137376 (published date: November 26, 2013, the title of the invention: a tool for cutting gears and a method for cutting gears)

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

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

Second, in the case of the cutting process, the cutting process for cutting the gear is complicated, and in order to manufacture one helical gear, it is necessary to cut dozens of teeth.

Third, even after the helical gear is manufactured through the cutting process, the helical gear requires a post process in order to operate normally. This post process step takes a long time and is expensive.

Recently, an apparatus 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 workpiece at a temperature below room temperature or a recrystallization temperature to improve the structure and molding.

In the case of such a cold forging process, the mechanical properties of the fabricated material can be improved by compressing the metal material compared to the cutting process, thereby improving the mechanical properties of the fabricated material, and reducing the waste of the raw material has a high economic effect. However, the conventional cold forging method has the following problems.

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

Secondly, as the durability of the mold decreases in a short time, the mold production cost is high, and there is a problem that the manufacturing cost increases.

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

In order to solve the above problems, an object of the present invention is to provide a multi-stage cold former for helical gear manufacturing using cold forging instead of cutting.

Multistage coldformer for manufacturing a helical gear according to an embodiment of the present invention, a multistage coldformer for manufacturing a helical gear including a plurality of manufacturing units including a mold unit and a plurality of pressurizing parts for forming a workpiece As a first manufacturing unit for manufacturing the main body of the helical gear; A second manufacturing unit for manufacturing a gear part of the helical gear; A third manufacturing unit for forming a groove or a hollow in the main body; A fourth manufacturing unit forming a first screw thread on the main body; And a fifth manufacturing unit forming a second screw thread on the gear part, wherein the second screw thread is formed in a shape having a twist setting angle from an upper end to a lower end of the gear part.

Multi-stage cold former for helical gear manufacturing according to an embodiment of the present invention constituting the above configuration has the following effects.

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

Second, since the strength of the metal material used for the production of the helical gear is sensed and pressurized to an appropriate pressure, the durability of the mold used is increased, thereby reducing the mold manufacturing cost.

Third, by dividing the process for manufacturing one helical gear into multiple stages and using a plurality of molds, the manufacturing time is reduced and the durability of the mold 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 multi-stage cold former for helical gear manufacturing according to an embodiment of the present invention
Figure 3 is a perspective view of the separation of the mold unit of the helical gear manufacturing unit of the configuration of the multi-stage cold former for helical gear manufacturing
Figure 4 is a side cross-sectional view of the helical gear manufacturing unit of the configuration of the multi-stage cold former for helical gear manufacturing
5 is a view showing a step of manufacturing a helical gear with a multi-stage cold former for manufacturing a helical gear according to an embodiment of the present invention.
6 is a flow chart of a helical gear manufacturing method through a multi-stage cold former for helical gear manufacturing according to an embodiment of the present invention.
Figure 7 is a side cross-sectional view of the second mold unit of 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 may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the invention.

2 is a perspective view of a helical gear manufacturing unit of a multi-stage cold former for helical gear manufacturing according to an embodiment of the present invention, Figure 3 is separated from the mold unit of the helical gear manufacturing unit of the configuration of the multi-stage cold former for manufacturing helical gear One is a perspective view, Figure 4 is a side cross-sectional view of the helical gear manufacturing unit of the configuration of the multi-stage cold former for helical gear manufacturing.

2 to 4, the mold unit of the helical gear according to the exemplary embodiment of the present invention may include a first pressing part 200 and a second pressing part 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 below the second mold unit 120, and the first pressing unit 200 is disposed above the first mold unit 110. 2 Pressing unit 300 is written based on the lower side of the second mold unit 120, but is not limited to the second mold unit 120 to the lower portion of the first mold unit 110. Note that this may also apply if deployed.

The first mold unit 110 is a metal material (hereinafter referred to as a work piece 20) into which the helical gear is formed. In detail, the first mold unit 110 includes the second mold unit. It is disposed above the 120 to maintain the state before the workpiece 20 is inserted and subjected to primary processing.

In addition, the workpiece 20 may be hollow formed inside the axial direction. That is, the workpiece 20 may have a cylindrical shape in which the inside is drilled in the axial direction.

The first mold unit 110 has a first mold body 112 is inserted into the workpiece 20, the first mold body 112 is formed with a first space 111 for the reciprocating movement of the first pressing portion 200, A mounting portion 113 disposed in the first space 111 to allow the workpiece 20 to be seated, and an outside 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 part 113 may be formed at one side of the first space 111, and in this case, the first pressing part 200 may reciprocate through the other side of the first space 111. Can be.

In addition, the first seating part 113 may have a size of a diameter in which the workpiece 20 is inserted and seated, and at the same time, does not move from side to side.

The first pressing part 200 is disposed above the first mold unit 110 to press the workpiece 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 unit 200 presses one surface of the workpiece 20, the workpiece 20 rotates and may 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 workpiece 20, in which case the workpiece 20 may be the first pressing part 200. It may 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 contacts the first inserting part 210 inserted into the hollow of the workpiece 20 and one surface of the workpiece 20 to press the workpiece 20. It may include a first contact portion 220. However, the first inserting part 210 may be omitted when a hollow is not formed in the workpiece 20.

The first inserting portion 210 is formed to have 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 workpiece 20, the first inserting part 210 is inserted into the hollow of the workpiece 20, so that the workpiece 20 is It is effective to prevent vibration or shaking.

The first contact portion 220 is formed to a diameter larger than the first inserting portion 210 is a means capable of pressing 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 is inserted into the first seating portion 113. However, one surface of the workpiece 20 may be pressed 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 in which the second pressing unit 300 reciprocates is formed. And a tooth forming portion 123 having a shape corresponding to the teeth to be formed on the outside of the workpiece 20 and the second mold body 122 to protect the second mold body 122. It may include a second housing surrounding the outside of the).

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

In more detail, when the workpiece 20 is disposed on the seating part 113, the first pressing part 200 rotates in contact with one surface of the workpiece 20 while rotating the workpiece 20. Pressurized 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 portion 200, A portion of the workpiece 20, that is, a portion for forming a tooth, may be inserted into the tooth forming portion 123 formed in the second space 121. Accordingly, a tooth corresponding to an inner shape of the tooth forming part 123 may be formed on an outer side of the inserted portion 20 of the workpiece 20.

In addition, the tooth forming unit 123 may be formed differently according to the manufacturing steps of the plurality of helical gear manufacturing unit of the multi-stage cold former for helical gear manufacturing 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. 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.

The second pressing portion 300 is disposed below the second mold unit 120, the workpiece is seated on the first mold unit 110 and the tooth is formed by the second mold unit 120. It is a means which presses 20 to the other side opposite to one side. For example, the second pressing part 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 portion 300 is in contact with the other surface of the workpiece 20 to extend from the second contact portion 310 and the second contact portion 310 to press the workpiece 20 and the second contact portion It may include a second insertion portion for supporting the 310 and reciprocating the second space 121 of the second mold body 122.

When the second contact portion 310 presses the other surface of the workpiece 20, the workpiece 20 inserted into the tooth forming portion 123 and having a tooth formed on the outside thereof may move upward. In this case, the workpiece 20 may be separated from the tooth forming portion 123 while the teeth formed on the outside of the workpiece 20 are more finely trimmed.

The helical gear manufacturing unit according to the embodiment of the present invention is connected to the first pressurizing part 200 so that the workpiece 20 when the first pressurizing part 200 presses the workpiece 20 firstly. The first pressure value measured by the sensor unit 230 and the sensor unit 230 that can measure the first pressure value applied by the first pressing unit 200 to the workpiece for plastic deformation of the Operation of the first pressing unit 200 and the second pressing unit 300 to allow the first pressing unit 200 and the second pressing unit 300 to press the workpiece 20 as a reference. The control unit may further include a control unit.

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

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

The control unit, when the sensor unit 230 measures the first pressure value, the first pressurizing unit 200 and the second pressurizing unit 300 is the workpiece at a predetermined pressure value based on the first pressure value Operation of the first pressing unit 200 and the second pressing unit 300 may be controlled to press the piece 20.

For example, when the first pressure value is 5 Pa, the controller 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. The first pressing unit 200 and the second pressing unit 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, equal to, or stronger than the first pressure value as set by the user. And the second pressing part 300 may press the workpiece 20.

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

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

Referring to Table 2, the experiment was performed by dividing the case where the first pressure values were 100 GPa and 200 GPa.

In the case where the first pressure value is 100 GPa, most of the defects occurred when the second pressure value was lower than 100 GPa, and in the same case, 31.1% of the defects occurred. The failure rate of 110GPa to 130GPa was less than 4%, but at 140GPa, it was measured as 14.5%, and the failure rate of the helical gear was higher at the moment when 30GPa was exceeded than the first pressure value. It is believed that the helical gear is damaged by excessive force.

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

Through the above experiment, the second pressure value was found to be the highest gear generation efficiency when 110% to 130% of the first pressure value.

Hereinafter, a multi-stage cold former for manufacturing a helical gear for manufacturing the workpiece 20 will be described.

The multi-stage cold former for manufacturing the helical gear may include one or more of the helical gear manufacturing units.

In detail, the multi-stage coldformer for manufacturing the helical gear may include a plurality of the helical gear manufacturing unit, in order to manufacture the workpiece 20 with various shapes of helical gears, in which case the workpiece ( 20) may be manufactured by the plurality of the helical gear manufacturing unit step by step to form a helical gear finally required by the user.

In the following embodiment, the multi-stage cold former for helical gear manufacturing may include six helical gear manufacturing units. However, this is only one embodiment, it should be noted that the number of the helical gear manufacturing unit may vary depending on the shape of the helical gear to be manufactured.

5 is a view illustrating a step of manufacturing a helical gear with a multistage coldformer for manufacturing a helical gear according to an embodiment of the present invention, and FIG. 6 is a multistage coldformer for manufacturing a helical gear according to an embodiment of the present invention. Flow chart of the helical gear manufacturing method.

Referring to FIG. 5, the multi-stage coldformer for manufacturing the helical gear may include first to sixth helical gear manufacturing units.

Referring to Figure 6, the helical gear manufacturing method, the material processing step (S110), the main body manufacturing step (S120), the gear manufacturing step (S130), the hollow forming step (S140), the main body teeth forming step (S150) ) And gear tooth forming step (S160). Hereinafter, a method of manufacturing the helical gear through a multi-stage cold former for helical gear manufacturing will be described in detail.

In detail, the material processing step S110 may be a step of manufacturing a workpiece 20 for manufacturing the helical gear from a metal material for the helical gear.

More specifically, 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 in order to manufacture the helical gear to be processed into the workpiece 20. have. Through the material processing step (S110) can be produced a cylindrical workpiece 20 for manufacturing the helical gear.

The main body manufacturing step (S120) may be a step of manufacturing the main body of the helical gear. In detail, in the main body manufacturing step (S120), the first helical gear manufacturing unit and the second helical gear manufacturing unit of the multi-stage cold former for manufacturing the helical gear may be used.

The first space 1111 of the first mold unit 1110 of the first helical gear manufacturing unit may have 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 cylindrical having a diameter smaller than the diameter of the workpiece 20 by the tooth forming portion 1123 disposed at 1112.

The workpiece 20 produced through the material processing step (S110) may be inserted into the first space 1111, and the first pressing part 1200 of the first helical gear manufacturing unit may have the workpiece. As the surface of the tooth 20 is pressed, the tooth forming part 1123 may be pressed toward the second space 1121. Accordingly, a portion of the workpiece 20 may be rotated and inserted into the second space 1121, and at the same time, may generate a portion having a smaller diameter by the tooth forming portion 1123. A portion of which the diameter is reduced in the workpiece 20 may be defined as a main body portion, whereby the main body 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 is the first main body portion 21 and the second main body portion ( A helical gear divided into 22) was manufactured. 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 that of 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 shape 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 unit manufacturing step (S130) is a step of manufacturing the gear unit 23 in which the teeth of the helical gear are formed on the outside of the workpiece 20. In the gear manufacturing step (S130), a third helical gear manufacturing unit of a multi-stage cold former for manufacturing the helical gear 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 be shaped to be inserted from the lower side through the first mold unit 3110 of the third helical gear manufacturing unit. In detail, the gear part 23 of the workpiece 20 may be inserted below through the first space 3111 of the first mold unit 3110.

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

The hollow forming step (S140) is a step in which a hollow is formed in the gear part 23 of the workpiece 20, so that the helical gear can be grooved to the outside. In the hollow forming step (S140), a fourth helical gear manufacturing unit of a multi-stage cold former for manufacturing the helical gear 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 above through the first space 4111 of the first mold unit 4110.

When the gear part 23 of the workpiece 20 is disposed in the second space 4121 of the second mold unit 4120 via the first space 4111 of the first mold unit 4110, the first pressing part is provided. The 4200 may press one surface of the workpiece 20, that is, a portion of the gear 23. In this case, the first insertion part 4210 of the first pressing part 4200 presses one surface of the gear part 23 to one surface of the gear part 23 supported by the second mold unit 4120. While being hollow, the gear part 23 may be formed.

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

In the fifth helical gear manufacturing unit, a first mold unit 5110 may be disposed below the second mold unit 5120. In addition, the teeth forming part 5123 disposed in the second space 5121 of the second mold unit 5120 may have a plurality of parallel threads extending laterally.

When the main body portions 21 and 22 of the workpiece 20 are inserted into the first space 5111 of the first mold unit 5110, the first pressing portion 5200 of the workpiece 20 A portion of the main body portion 22 may be pressed to press the gear portion 23 so as to be inserted into the second space 5121 of the second mold unit 5120. In this case, a parallel threaded tooth may be formed on a part of the main body part 22 of the workpiece 20 by the tooth forming part 5123 formed in the second space 5121.

The gear tooth forming step (S160) is a step of forming a thread of the helical gear by forming a helical tooth in the gear part 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, a first mold unit 6110 may be disposed below the second mold unit 6120. In addition, the tooth forming part 123 disposed in the second space 6121 of the second mold unit 6120 may include a plurality of grooves extending from the upper end of the second space 6121 to the lower end. In this case, the plurality of grooves may have a spiral shape of a set angle or a set curvature. In detail, the setting 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 in the configuration of the helical gear manufacturing unit.

Referring to FIG. 7, the tooth forming portion 123 having the groove for forming the helical gear in the second mold unit enters through the front region A1 to which the initial workpiece enters and the front region A1. It may be divided into a rear region A2.

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

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

In the following, first, the setting angle α and the tooth spacing of the tooth forming portion 123 of the rear region A2 for forming the effective helical gear will be described.

In the following, according to the set angle (α), it is confirmed the results of the experiment how the durability of the mold changes.

Table 2 is the data confirming the number of the helical gear taken out until the mold is damaged by the angle of the set angle (α).

Mold thickness Tooth spacing Set 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 4mm 9 ° 11,017 50 mm 4mm 12 ° 16,158 50 mm 4mm 15 ° 17,971 50 mm 4mm 20 ° 17,024 50 mm 4mm 25 ° 13,220 50 mm 4mm 28 ° 11,845

Referring to Table 1, the second mold was measured utilizing 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 gap of 2 mm. The third type is a mold unit with a mold thickness of 500 mm and a tooth gap of 4 mm. .

Here, the mold thickness of the second mold is the vertical length of the tooth forming portion for forming the helical gear, and it was confirmed in advance that the optimum yield was obtained when it was between 30 mm and 50 mm.

In detail, the second mold unit is a mold for forming a helical gear through restraint molding, wherein one end of the tooth forming portion is an opening for entering the workpiece and the other end is closed to prevent the workpiece from entering further. After entering through the opening is blocked by the closing portion is expanded by the force applied vertically to the groove side of the tooth forming portion of the mold 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 such restraint close to the vertical (at least 0.2 ° or less), the length of the tooth forming portion of the second mold unit, In other words, the mold thickness should be 30mm to 50mm. More preferably, in order to maintain the concentricity angle within 0.1 °, it was confirmed through experiment that the thickness of the second mold unit is between 38mm and 45mm.

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

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

In the third type of mold unit, less than 12,000 helical gears were produced when the set angle (α) was 9 ° and 28 °, and the number of helical gears increased rapidly when the set angle (α) was 12 °. In addition, it was confirmed that the number of helical gear production drastically decreased while the set angle α exceeded 24 °.

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 most robust. 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.

Therefore, 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 gear part tooth forming step (S160), when the gear part 23 of the workpiece 20 is inserted into the first space 111 of the first mold unit 110, the first pressing part 200 is formed. The gear part 23 of the workpiece 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, teeth of a shape corresponding to the plurality of grooves may be formed on the outer surface of the gear part 23 by the tooth forming part 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 the set angle α, the workpiece is excessively impacted from the beginning and the principle of action reaction Too much impact on the groove of the second mold unit may damage the mold.

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

Through experiments, it was found that the initial groove angle of the grooves of 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, direct damage to the coating of the tooth forming portion 123 of the initial mold could be visually confirmed by the workpiece.

Preferably, the initial groove angle among the angles β of the grooves of the front region A1 may be confirmed through experiments that is greater than 4 ° and less than 6 °. When the initial groove angle of the tooth forming portion 123 is set to 4 ° or less, the front region A1 until going to the rear region A2 of the tooth forming portion 123 formed at the set angle α is included. 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) is reduced among the helical gears of the workpiece. And when the initial groove angle of the teeth forming portion 123 is set to 6 ° or more, there is a problem that the yield is sharply reduced due to excessive impact on the initial entry groove of the teeth forming portion 123 of the mold.

Next, the initial groove angle of the front region A1 is gradually increased so that the groove angle β of the last rear end may be the 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 the set angle α (eg, more than 14 ° 16). Less than °) to be equal.

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

Similarly, the tooth gap, which is the initial groove depth of the tooth forming portion 123 of the front region A1, converges to almost zero, and the depth increases at a predetermined slope at one point, so that the tooth interval, which is the depth of the rear groove, 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 toothing portion 123 is formed at a depth of 0,5 mm to 1.2 mm to cushion the entry of the toothing portion 123 of the workpiece, and 8 ° to 12 ° at one point. As the depth increases, the groove depth may be formed to be 4 mm, which is the set tooth spacing, in the rear region A2.

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 impacts the coating of the workpiece and the mold groove as much as possible. In order to alleviate, the depth of the initial groove is smaller than the set tooth depth, and the groove depth is increased at a predetermined 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. Tooth spacing 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 thus, the workpiece and the mold groove. In order to mitigate the impact to the coating as much as possible, the groove angle and tooth spacing of the front region A1 gradually increase so that the groove angle and tooth spacing of the rear stage are the angle of the groove of the rear region A2 to form a valid helical gear. Can be equal to the set angle α and the tooth spacing.

Further, the tooth forming portion 123 may be added with a special coating for relieving the impact and entering 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 portion of the front region A1 is a key point for determining the life of the mold, it may be a second special coating agent having high elasticity and high rigidity to flexibly accept the entry of the workpiece regardless of cost. have.

This 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 high in elasticity, it may be inadequate for effective helical gear formation. Therefore, the coating of the tooth forming portion 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. Can be relatively low.

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

The multi-stage coldformer for manufacturing the helical gear of the configuration as described above by manufacturing the helical gear in each step through a number of helical gear manufacturing unit, not only can save the manufacturing time and manufacturing cost of the helical gear, the setting There is an effect that can increase the durability of the mold by adjusting the angle (α).

Claims (4)

In the multi-stage cold former for manufacturing a helical gear including a mold unit and a plurality of manufacturing units including a plurality of press units for forming a workpiece,
A first manufacturing unit for manufacturing a main body of the helical gear;
A second manufacturing unit for manufacturing a gear part of the helical gear;
A third manufacturing unit for forming a hollow in the main body;
A fourth manufacturing unit forming a first screw thread on the main body; And
A fifth manufacturing unit forming a second screw thread on the gear part,
The second thread is formed in a shape having a torsional setting angle from the upper end to the lower end of the gear unit,
The fifth manufacturing unit may include a first mold unit including a first space in which the workpiece is compressed and a seating portion having a diameter smaller than the first space in which the workpiece is seated in the first space; A second mold unit disposed below the first mold unit, the second mold unit including a second space formed at a corresponding position of the first space and having a tooth forming portion corresponding to the second thread on an inner surface thereof; A first pressing part disposed above the first mold unit to rotate and press one surface of the workpiece in a direction corresponding to the second screw thread; And a second pressing part disposed below the second mold unit to press the other surface of the workpiece upward after the operation of the first pressing part to separate the workpiece from the tooth forming part.
The first pressing part may include a first insertion part formed to have the same diameter as the hollow of the workpiece, and a first contact part formed on the first insertion part with a diameter larger than that of the first insertion part to press one surface of the workpiece. Including,
Is formed in the side of the first insertion portion and the sensor portion for measuring the pressure value when pressing the hollow of the workpiece, and disposed in the groove of the tooth forming portion of the second mold unit is the workpiece penetrated into the groove An additional sensing module for directly detecting whether or not, and a control unit for controlling the operation of the first pressing unit and the second pressing unit based on the pressure value measured from the sensor unit and the additional sensing module,
The control unit,
After operating the first pressurizing unit, the minimum stress value causing plastic deformation of the workpiece is determined by the pressure value measured by the sensor unit at the time when the workpiece detects the inlet into the mold groove in the additional sensing module. The test pressurization determined by the value is performed, and the pressurization pressure of the first pressurization unit and the pressurization pressure of the second pressurization unit are set to the second pressure value determined based on the first pressure value.
Multi-stage coldformer for helical gear manufacturing. delete delete The method of claim 1,
The thickness of the second mold unit is between 30mm and 50mm, the tooth spacing of the second mold unit is 1.5mm to 4mm, the set angle indicating the direction in which the plurality of grooves formed in the second mold unit extends 12 It is characterized in that the degree to 24 degrees
Multi-stage coldformer for helical gear manufacturing.

Images