KR20230139892A - Manufacturing method of support ring - Google Patents

Abstract

The method of manufacturing a support ring for a motor support ring for an automobile according to the present invention includes preparing raw materials; A heating step of heating the raw material to a recrystallization temperature or higher; An upsetting step of upsetting the heated raw material to form a disk-shaped workpiece with bulged sides and flat upper and lower surfaces; A hot forging process of forming the workpiece into a blank shape having an upper annular flange, an upper groove, a lower groove, and a web between the upper groove and the lower groove, and a piercing process of piercing the web. ; A support ring forming ring rolling step for manufacturing a support ring while seating the blank between the mandrel and the main roll and rotating it to extend it in the circumferential direction; gradually enlarging the blank and reducing its thickness; and a trimming step of forming a flange protrusion by trimming the upper annular flange of the support ring produced in the support ring forming ring rolling step.

Description

Manufacturing method of support ring {Manufacturing method of support ring}

The present invention relates to a method of manufacturing a support ring, and relates to a method of manufacturing a support ring for a motor support ring (SUPPORT RING) for an automobile through a continuous process from raw materials.

Hybrid vehicles, generally referred to as eco-friendly vehicles, refer to vehicles driven by an engine that obtains rotational power by burning fuel (fossil fuels such as gasoline) and an electric motor that obtains rotational power by battery power.

Hybrid vehicles use both the mechanical energy of the engine and the electrical energy of the battery, utilize the optimal operating range of the engine and electric motor, and recover energy through the electric motor during braking, thereby improving fuel efficiency and using energy more efficiently.

This electric motor for a hybrid vehicle is combined with an automatic transmission, which is the driving element of the vehicle. The electric motor is installed inside the transmission housing of the automatic transmission, and a motor housing that supports the electric motor and seals the transmission housing is fastened to the transmission housing. The electric motor has a stator core of a centralized winding split core type. The stator core is fixedly installed inside the transmission housing, and the rotor is integrally mounted on the motor shaft of the electric motor.

Meanwhile, in electric motors, a large amount of heat is generated due to eddy currents generated in the stator core, so cooling is essential to prevent damage from the heat and ensure continuous stable operation.

In hybrid vehicles, where the motor is mainly fixed inside the transmission, a cooling method using transmission oil and a cooling method using coolant are used to cool the electric motor. For example, looking at the cooling structure of an electric motor through coolant, a support ring for fixing the stator core to the transmission housing and cooling the stator core is installed between the stator core and the transmission housing.

A coolant flow path is formed between the outer peripheral surface of the support ring and the inner peripheral surface of the transmission housing to allow coolant to flow through a groove provided on the outer peripheral surface of the support ring, and the coolant flow path is sealed through an O-ring. Coolant flowing through the coolant flow path can cool the heat generated in the stator core.

This automobile motor support ring is a part that requires heat resistance and shock resistance, and is usually a part with a large outer diameter of Φ350 mm or more and a thickness of about 100 mm, and has flange protrusions arranged asymmetrically on the outer peripheral surface. The standard of the support ring is not limited to the examples described above, but it is a large diameter part with a large outer diameter.

The hot forging method has traditionally been used as a manufacturing method for such support rings. By heating the round bar-shaped raw material and performing multiple blows using forging equipment such as an air drop hammer, the raw material is formed into a material with an open top and a closed bottom. Afterwards, the blocked lower part of the material is pierced through a piercing process, and the upper part of the material is trimmed to manufacture a support ring.

However, this conventional support ring manufacturing method involves striking a round bar-shaped raw material and forging it to a size suitable for an outer diameter of Φ350 mm or more, which has the problem of short mold life and the need for large-capacity press equipment. It is known that the general press forging method requires an equipment capacity of approximately 8000 tons or more.

As a method of manufacturing a support ring to solve this problem, a method of expanding the pipe into a tapered shape using a mold from a semi-processed material in the form of a hollow seamless pipe, and forming and trimming the upper and lower flanges through a forging process is known. It is done.

However, since this process uses semi-processed materials that have already been processed in the form of a large-diameter hollow seamless pipe with a large outer diameter of about Φ350 mm, it requires the supply of semi-processed materials, which causes an increase in unit prices. Semi-finished materials in the form of hollow seamless pipes with a large outer diameter must be manufactured through separate plastic processing, such as a drawing process, using raw steel materials.

Republic of Korea Patent Publication No. 1428663 (2014.08.04)

The purpose of the present invention is to provide a support ring manufacturing method that can manufacture a support ring for an automobile motor support ring from a round bar-shaped raw material.

The present invention manufactures a support ring that reduces the required forging press equipment capacity by manufacturing a small-diameter blank from raw materials through an upsetting process and a hot forming process, and performing a ring rolling process and trimming process in a continuous process. The purpose is to provide a method.

The method of manufacturing a support ring for a motor support ring for an automobile according to the present invention includes preparing raw materials; A heating step of heating the raw material to a recrystallization temperature or higher; An upsetting step of upsetting the heated raw material to form a disk-shaped workpiece with bulged sides and flat upper and lower surfaces; A hot forging process of forming the workpiece into a blank shape having an upper annular flange, an upper groove, a lower groove, and a web between the upper groove and the lower groove, and a piercing process of piercing the web. ; A support ring forming ring rolling step for manufacturing a support ring while seating the blank between the mandrel and the main roll and rotating it to extend it in the circumferential direction; gradually enlarging the blank and reducing its thickness; and a trimming step of forming a flange protrusion by trimming the upper annular flange of the support ring produced in the ring rolling step.

According to one aspect of the present invention, in the blank hot forming step, the blank has an upper inclined side wall tapered at a first angle, a lower inclined side wall tapered at a second angle, and an inner peripheral surface having a thick portion in the middle portion. It is produced in the form

According to one aspect of the present invention, the second angle is formed as an angle larger than the first angle.

According to one aspect of the present invention, the first thickness (t1) between the outer diameter of the blank and the top of the upper inclined side wall is greater than the second thickness (t2) between the outer diameter and the lower end of the lower inclined side wall, and the support ring is It has an upper inner diameter inclined portion and a cylindrical inner diameter portion lower than the inner diameter inclined portion, so that a thickness t1' between the outer diameter of the support ring and the upper end of the inner peripheral surface of the support ring is the distance between the outer diameter of the support ring and the lower end of the inner peripheral surface of the support ring. It is manufactured smaller than the thickness (t2').

According to one aspect of the present invention, the main roll for the support ring forming ring rolling step has a flange forming groove in which the upper annular flange of the blank is disposed, and the mandrel for the support ring forming ring rolling step is , It is provided with an upper inclined outer peripheral surface having an outline whose diameter decreases toward the lower side and a lower cylindrical outer peripheral surface connected to the lower side of the upper inclined outer peripheral surface.

According to one aspect of the present invention, before performing the trimming step, a partial heating step of heating the upper annular flange of the support ring is further performed on the support ring formed after the support ring forming ring rolling step, The partial heating step may be a direct heating method in which flame is directly applied to the upper annular flange of the support ring to heat it.

According to the manufacturing method of the support ring according to the present invention, it is possible to manufacture the support ring starting from a raw material in the form of a round bar, so compared to the method of manufacturing the support ring starting from a seamless hollow pipe in the form of a semi-finished product, the material Supply and demand are easy and the production cost of the product can be reduced.

According to the manufacturing method of the support ring according to the present invention, the support ring is manufactured by enlarging the diameter from a small diameter blank through the ring rolling method, so the material utilization rate is higher than the method of manufacturing a large diameter support ring through the forging method from raw materials. This has the advantage of lowering manufacturing costs by reducing scrap generation.

The support ring manufacturing method according to the present invention makes it possible to use press equipment with a relatively small equipment capacity, which has the advantage of reducing process equipment costs.

1 is a flowchart of a method for manufacturing a support ring according to the present invention.
Figure 2 is a diagram for explaining the process of manufacturing a blank according to the support ring manufacturing method according to the present invention.
Figure 3 is a cross-sectional view of a blank manufactured according to the support ring manufacturing method of the present invention.
Figure 4 is a diagram for explaining the ring rolling step and support ring of the support ring manufacturing method according to the present invention.
Figure 5 is a diagram for explaining the trimming step in the support ring manufacturing method according to the present invention.

Since the present invention can be subject to various changes and can have various forms, embodiments will be described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. While describing each drawing, similar reference numerals are used for similar components.

The above terms are used only for the purpose of distinguishing one component from another. The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a flowchart of a method of manufacturing a support ring according to the present invention, Figure 2 is a diagram illustrating the process of manufacturing a blank according to the method of manufacturing a support ring according to the present invention, and Figure 3 is a method of manufacturing a support ring of the present invention. It is a cross-sectional view of the blank manufactured according to the present invention, Figure 4 is a diagram for explaining the ring rolling step and the support ring in the support ring manufacturing method according to the present invention, and Figure 5 is a trimming step in the support ring manufacturing method according to the present invention. This is a drawing for this purpose.

Referring to the drawing, the support ring manufacturing method according to the present invention includes preparing raw materials (S10), heating step (S20), upsetting step (S30), blank hot forming step (S40), support ring forming, and ring rolling. It includes a step (S50) and a trimming step (S50).

In the step of preparing the raw material (S10), a round bar-shaped raw material with a length longer than the diameter is provided. In general, this is done by cutting the steel material supplied in the form of a long round bar into raw material 10 in the form of a round bar having a calculated length for the subsequent process.

The heating step (S20) is performed by uniformly heating the cut round bar-shaped raw material (10) provided in the step of preparing the raw material (S10) to a recrystallization temperature or higher. In the heating step (S20), it is heated to a temperature commonly used for the hot forging process, and the raw material 10 can be heated to about 1150°C to 1250°C.

The heating step (S20) uses a method of heating the raw material 10 using a high-frequency induction heating method.

According to an embodiment of the present invention, the raw material 10 heated in the heating step (S20) continuously undergoes an upsetting step (S30), a blank hot forming step (S40), and a support ring forming ring rolling step (S50) described later. The process goes through sequentially.

That is, after blank hot forming of the heated raw material 10 in the heating step (S20), the support ring forming ring rolling step (S50) is continuously performed without additional heating using latent heat, that is, residual heat.

The upsetting step (S30) applies compressive force in the longitudinal direction to the heated raw material 10 to reduce the length, and flows the material in a direction perpendicular to the longitudinal direction to create a workpiece (20) for producing a blank. Manufactured (see (b) in FIG. 2).

In the upsetting step (S30), the raw material is molded into a disk-shaped workpiece 20 with swollen sides and flat upper and lower surfaces. In the upsetting step (S30), the workpiece 20 is formed into a shape having an outer diameter similar to that of the blank 30.

The blank hot forming step (S40) includes a hot forging process (S42) and a piercing process (S44).

In the hot forging process (S42), the blank 30 having the web 45 is manufactured by hot-sealing and forging the upset workpiece 20 using a finisher mold set.

The hot forging process (S42) can be performed using an upper mold and a lower mold that are joined together to form a sealed molding space inside.

Referring to Figure 2 (c) and Figure 3, in the hot forging process (S42), the blank 30 is manufactured in an axis-symmetrical shape with respect to the central axis (L), and has an upper annular flange 32 and an upper groove ( 34), a lower groove 37, and a web 45 that blocks the hollow across the thick portion 42 between the upper groove 34 and the lower groove 37.

In the blank 30, the upper groove 34 has an upper inclined side wall 35 tapered at a first angle α, and the lower groove 37 has a lower inclined side wall 38 tapered at a second angle β. ) is provided.

According to an embodiment of the present invention, the first angle (α) and the second angle (β) are set within the range of 8 to 28°. The second angle (β) is formed to be larger than the first angle (α), and the second angle (β) may be set to be 2 times or more and 3 times or less than the first angle (α).

The configuration of the upper inclined side wall 35 and the lower inclined side wall 38 is such that the blank 50 is enlarged by the external force applied by the mandrel 120 in the support ring forming ring rolling step (S50) and the support ring 60 is formed. When this is formed, the moving pressure of the flesh (material) to the upper annular flange 32 portion is improved, making it possible to make the structure of the upper annular flange 62 of the support ring 60 dense and improve the strength. .

The first thickness t1 between the outer diameter of the blank 30 and the top of the upper inclined side wall 35 is formed to be larger than the second thickness t2 between the outer diameter and the lower end of the lower inclined side wall 38.

The lower end of the upper inclined side wall 35 of the upper groove 34 and the upper end of the lower inclined side wall 38 of the lower groove 37 are located opposite to each other with the web 45 of the blank 30 as a boundary, and the upper Due to the tapered shape of the inclined side wall 35 and the lower inclined side wall 38, a thick portion 42 is formed in the middle portion of the inner peripheral surface where the web 45 is formed.

The piercing process (S44) pierces the web 45 of the blank 30. Through piercing, the upper groove 34 and lower groove 37 of the blank 30 communicate with each other.

By the blank hot forming step (S40), the blank 30 has an axially symmetrical shape with respect to the central axis L, as shown in FIG. 3, and has an upper annular flange ( 32) is provided. Additionally, the blank 30 has a hollow shape with an inner peripheral surface having an upper inclined side wall 35, a lower inclined side wall 38, and a thick portion 42 located in the middle portion where the web 45 is removed.

The blank 30 has the status of a semi-processed product for manufacturing the support ring 60.

The blank 30 is formed into the support ring 60 through the support ring forming ring rolling step (S50). When the blank 30 is formed into the support ring 60, the blank 30 is enlarged by more than 1.5 times the outer diameter. The inner diameter can be expanded to 2.5 times or more based on the inner diameter of the thick part. The design of the blank 30 described above allows the height change to be appropriately controlled when the diameter is expanded through ring rolling, that is, to increase the height. It is possible to form a small diameter blank 30 into a large diameter support ring 60 while minimizing the external force required in the ring rolling step. The design of the blank 30 described above ensures that it can be manufactured without process defects if the support ring 60 has uniform strength due to the external force applied to the blank by the mandrel 120 of the ring rolling device 100. .

The support ring forming ring rolling step (S50) is a process of using a small diameter blank 30 as a material and enlarging the diameter while reducing the thickness to have the outer and inner diameters required for the support ring 60 in a ring rolling device.

According to an embodiment of the present invention, the ring rolling step (S50) is performed using latent heat after the blank hot forming process without reheating the blank 30. That is, it is transferred to the ring rolling device in a continuous process without reheating, and the ring rolling step (S50) is performed.

Referring to FIG. 4, the ring rolling device 100 includes a main roll 110 and a mandrel 120 on which a flange forming groove 115 is formed on the outer peripheral surface.

The outer peripheral surface of the blank 30 is in contact with the outer peripheral surface of the main roll 110, and the upper annular flange 32 of the blank 30 is disposed in the forming groove 115 of the main roll 110. At this time, the flange forming groove 115 of the main roll 110 may be formed larger than the upper annular flange 32 of the blank 30.

The mandrel 120 is in contact with the inner peripheral surface of the blank 30, and when the forming process begins while in contact, the blank 30 rotates between the main roll 110 and the mandrel 120 and is stretched in the circumferential direction. As the cross-section gradually deforms, the diameter becomes wider.

The ring rolling device 100 shown in the drawing shows an open type ring rolling device without upper and lower work rolls, but is not limited thereto. However, the design of the blank 30 described above makes it possible to gradually deform and widen the cross-section while minimizing height increase without a work roll.

The mandrel 120 of the ring rolling device 100 has an upper inclined outer peripheral surface 130 and a lower cylindrical outer peripheral surface 140 below it.

The upper inclined outer peripheral surface 130 has an angle corresponding to the first angle α of the upper inclined side wall 35 of the blank 30 and extends in a form whose cross-section is reduced toward the lower cylindrical outer peripheral surface 140. You can. When the upper inclined outer peripheral surface 130 contacts the upper inclined side wall 35 of the blank, diameter enlargement forming is performed by first contacting the upper end of the upper inclined side wall 35 and the upper inclined outer peripheral peripheral surface 130 of the mandrel 120. The angle of the upper inclined outer peripheral surface 130 may be set as much as possible.

In the ring rolling step (S50), the spokes of the thick portion 42 begin to flow outward by the mandrel 120, thereby forming the diameter. Due to the presence of the thick portion 42, the change in height is minimized and the thickness is reduced. It is advantageous for the diameter to be expanded so that the cross-section is gradually reduced as it decreases.

The upper inclined outer peripheral surface 130 of the mandrel 120 contacts the upper inclined side wall 35 to apply an external force in a downward inclined direction. When the blank 30 is formed into the support ring 60, the spokes induce movement of the upper annular flange 62 and the expansion direction.

Due to the design of the upper inclined outer peripheral surface 130 of the mandrel 120 and the upper inclined side wall 35 of the blank 30, the spokes of the blank do not receive external force in the upward moving direction and move in the direction toward the upper annular flange. Since the flow is induced, it is possible for the upper annular flange to be formed with uniform strength and precise dimensions with the body portion 65 without combining pores, etc.

The support ring 60 manufactured by the support ring forming ring rolling step (S50) is formed by forming a small blank 30 with an outer diameter D1 into a large diameter support ring 60 with an outer diameter D2 in the ring rolling step. D2 can be set to Φ350mm or more, and the thickness is reduced to be molded to have a thickness of about 100mm.

As shown in (b) of FIG. 4, the support ring 60 is formed to have an inner diameter inclined portion 66 and a cylindrical inner diameter portion 67 inclined downward toward the central axis formed at the upper portion of the inner diameter. Therefore, in the body portion 65 of the support ring 60, the thickness t1' between the outer diameter and the top of the inner circumferential surface of the support ring is formed to be smaller than the thickness t2' between the outer diameter of the support ring and the lower end of the inner circumferential surface of the support ring. do.

Next, as shown in FIG. 5, a trimming step (S60) is performed. The trimming step (S60) is a step of forming the flange protrusion 70 by trimming the upper annular flange 62 of the support ring 60.

According to an embodiment of the present invention, a partial heating step (S55) of heating the upper annular flange 62 portion of the support ring 60 may be further performed before performing the trimming step (S60).

After the raw material is heated in the heating step (S20), the support ring 60 is manufactured through the blank hot forming step (S40) and the ring rolling step (S50) sequentially in a continuous process, so the support ring 60 is each It cools down gradually through stages.

The support ring 60 manufactured in the support ring forming ring rolling step (S50). At the end of the ring rolling stage, the temperature drops to between 850 and 950°C.

The partial heating step (S55) partially heats the upper annular flange 62 of the support ring 60 to be trimmed, thereby raising the upper annular flange 62 to a recrystallization temperature suitable for hot forming.

When the support ring 60 is placed in the trimming mold and a trimming process is performed on the upper annular flange 62, the body portion 65 of the cooled and hardened support ring 60 is subjected to the pressure applied during the trimming step (S60). Even when subjected to shock, deformation is suppressed.

Through partial heating, the body portion 65 of the support ring 60 maintains the strength formed by hardening and is brought to a temperature at which hot trimming is easy only for the upper annular flange 62. Therefore, it is possible to prevent tissue stability and tissue damage of the support ring 600 due to impact during the trimming process.

It is possible to significantly reduce the press weight required for the trimming step (S60) through partial heating of the upper annular flange (62). For example, if there is no partial heating, it is predicted that a press equipment capacity of about 1000 tons is needed, but if partial heating is performed, a trimming press equipment capacity of 300 tons or less can be used.

According to an embodiment of the invention, partial heating is performed by directly heating the upper annular flange portion by means of a flame. Due to the direct heating method, the upper annular flange is advantageous in allowing more rapid partial heating by applying heat equal to the required temperature increase in addition to latent heat.

The support ring manufactured in this way becomes a semi-finished product for cutting processing, and after cooling, is transferred for finishing processing such as cutting processing.

The above description of the present invention is for illustrative purposes, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. will be. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

10: Raw materials
30: Blank 32: Upper annular flange
34: upper groove 35: upper inclined side wall
37: lower groove 38: lower inclined side wall
42: thick portion 45: web
60: Support ring 62: Upper annular flange
66: downward inner diameter inclined portion 67: cylindrical inner diameter portion
70: Flange projection
100: ring rolling device 110: main roll
120: Mandrel 130: Upper inclined outer peripheral surface
140: Lower cylindrical outer peripheral surface

Claims (7)

A method of manufacturing a support ring for a motor support ring for an automobile,
Preparing raw materials;
A heating step of heating the raw material to a recrystallization temperature or higher;
An upsetting step of upsetting the heated raw material to form a disk-shaped workpiece with bulged sides and flat upper and lower surfaces;
A hot forging process of forming the workpiece into a blank shape having an upper annular flange, an upper groove, a lower groove, and a web between the upper groove and the lower groove, and a piercing process of piercing the web. ;
A support ring forming ring rolling step for manufacturing a support ring while seating the blank between the mandrel and the main roll and rotating it to extend it in the circumferential direction; gradually enlarging the blank and reducing its thickness; and
A method of manufacturing a support ring, comprising a trimming step of forming a flange protrusion by trimming the upper annular flange of the support ring produced in the support ring forming ring rolling step.
According to paragraph 1,
In the blank hot forming step,
The blank is manufactured in a form having an upper inclined side wall tapered at a first angle, a lower inclined side wall tapered at a second angle, and an inner peripheral surface having a thick portion in the middle.
According to paragraph 2,
A method of manufacturing a support ring, characterized in that the second angle is formed as an angle larger than the first angle.
According to paragraph 2 or 3,
A first thickness (t1) between the outer diameter of the blank and the top of the upper inclined side wall is greater than a second thickness (t2) between the outer diameter and the lower end of the lower inclined side wall,
The support ring has an upper inner diameter inclined portion and a cylindrical inner diameter portion lower than the inner diameter inclined portion, so that a thickness t1' between the outer diameter of the support ring and the top of the inner peripheral surface of the support ring is measured from the outer diameter of the support ring to the support ring. A method of manufacturing a support ring, characterized in that it is smaller than the thickness (t2') between the bottom of the inner peripheral surface.
According to paragraph 2,
The main roll for the support ring forming ring rolling step has a flange forming groove in which the upper annular flange of the blank is disposed,
The mandrel for the support ring forming ring rolling step includes an upper slanted outer peripheral surface with a contour whose diameter decreases toward the bottom and a lower cylindrical outer peripheral surface connected to the lower side of the upper inclined outer peripheral surface. Manufacture of a support ring. method.
According to paragraph 1,
For the support ring formed after the support ring forming ring rolling step,
Before performing the trimming step, a method of manufacturing a support ring, characterized in that a partial heating step of heating the upper annular flange of the support ring is further performed.
According to clause 6,
The partial heating step is a method of manufacturing a support ring, characterized in that a direct heating method is applied in which flame is directly applied to the upper annular flange of the support ring to heat it.

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