WO2022124608A1

WO2022124608A1 - Drive shaft for automobile, and apparatus and method for manufacturing same

Info

Publication number: WO2022124608A1
Application number: PCT/KR2021/016591
Authority: WO
Inventors: 윤원석; 조태선; 박상원; 송기용
Original assignee: 일진제강(주)
Priority date: 2020-12-08
Filing date: 2021-11-15
Publication date: 2022-06-16
Also published as: KR20220081150A; KR102474930B1

Abstract

The present invention relates to a drive shaft for an automobile, and an apparatus and method for manufacturing same. The apparatus for manufacturing the drive shaft for an automobile according to the present invention may comprise: a clamping unit which fixes the central portion of a material and exposes both locally heated ends; tube compression dies which are arranged on both sides of the clamping unit and can move forward and backward with respect to the clamping unit, the tube compression dies being provided with holes that pass through in the axial direction of the material and have a first entrance part in the direction of the clamping unit and a second entrance part on the opposite side from the clamping unit; and mandrels arranged on both sides of the tube compression dies and capable of moving forward and backward via the second entrance parts of the holes of the tube compression dies.

Description

Drive shaft for automobile, manufacturing apparatus and manufacturing method thereof

The present invention relates to a drive shaft for a vehicle, an apparatus for manufacturing the same, and a manufacturing method thereof, and more particularly, to a hollow drive shaft, an apparatus for manufacturing the same, and a manufacturing method thereof.

In general, various drive shafts are used in automobiles. The drive shaft is largely divided into a solid type drive shaft and a hollow type drive shaft.

The manufacturing method of the solid drive shaft will be described as follows.

The solid drive shaft is made using a solid material. The drive shaft is made by turning, rolling, and high-frequency heat treatment of solid materials. However, the solid drive shaft has a disadvantage in that the weight of the vehicle increases and noise and rotational vibration are large.

In order to compensate for the shortcomings of the solid drive shaft, a hollow drive shaft has been widely used in recent years. A method of manufacturing a hollow drive shaft is largely divided into a welding method, a swaging method, and an upsetting method.

On the other hand, various parts connected to the vehicle wheel, transmission, etc. are assembled at both ends of the drive shaft. In order to effectively assemble these parts to both ends of the drive shaft, machining (hereinafter referred to as 'post-processing' for convenience), such as machining, roll forming, etc., is performed on both ends of the manufactured hollow drive shaft.

Therefore, both ends of the hollow drive shaft must have a thickness that allows post-processing such as machining or roll forming. In addition, both ends of the hollow drive shaft must have strength to support the parts coupled thereto.

As a result, both ends of the hollow drive shaft must satisfy predetermined conditions, such as a thickness that can be post-processed and a thickness that can support the mating counterpart.

A welding method will be described.

Both ends are manufactured by forging a round bar so as to satisfy the predetermined conditions of both ends. The manufactured both ends are joined to a hollow material by friction welding to make a drive shaft.

In the welding method, three sub-parts are needed to make one drive shaft, and there is a disadvantage that the bead cutting and polishing process of the welded area must be added after welding.

In the swaging method and the upsetting method, a hollow drive shaft is made using a single hollow material.

In the swaging method, the thickness of both ends of the hollow material is increased (thickened) by swaging. (Patent Publication No. 10-2011-0105660, etc.)

In the swaging method, the outer diameter of both ends of the material decreases and the thickness increases. As the outer diameter of both ends of the material decreases, the thickness increases. However, in the swaging method, since the material is stretched in the longitudinal direction while the outer diameter is reduced at the same time, the increase in the thickness of the material does not contribute to the increase in the lengthwise direction.

Therefore, in the swaging method, there is a limit to increasing the thickness of both ends of the material, and thus it is difficult to obtain a desired thickness.

Even in the upsetting method, a hollow drive shaft is made using a single hollow material. In the upsetting method, the thickness of both ends of the hollow material is increased by upsetting. (Patent Publication No. 10-2020-0036376, etc.)

In the upsetting method, in general, the outer diameter of both ends of the material increases or the thickness increases while being the same. In the upsetting method, there is a problem that the amount of thickening at both ends of the material may increase unnecessarily. If the amount of thickening at both ends of the material is unnecessarily increased, there is a disadvantage in that the processing time increases and material loss increases in post-processing such as a machining process after manufacturing the drive shaft.

This is because, if the amount of thickening at both ends of the upsetting-processed material is unnecessarily large, machining time increases and material loss increases because it is necessary to turn the unnecessarily thickened portion in machining.

In order to solve such a problem, an object of the embodiment of the present invention in order to solve the above problem is to provide a drive shaft for a vehicle capable of efficiently obtaining a desired increase in weight, an apparatus for manufacturing the same, and a manufacturing method thereof.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drive shaft for an automobile, a manufacturing apparatus therefor, and a manufacturing method thereof, in which post-processing is efficient and material loss can be reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drive shaft for a vehicle capable of improving the disadvantages of the swaging method and the upsetting method, an apparatus for manufacturing the same, and a method for manufacturing the same.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drive shaft for a vehicle capable of simplifying a manufacturing process, an apparatus for manufacturing the same, and a manufacturing method thereof.

In order to achieve the above technical problem, in the present invention, by performing the shaft pipe step and the upset step, both ends of the drive shaft for a vehicle can be increased to a desired thickness. That is, both ends of the material are primarily thickened in the shaft tube step and are secondarily thickened in the upsetting step. The shaft tube step and the upsetting step may be performed substantially simultaneously.

To this end, an apparatus for manufacturing a drive shaft for a vehicle according to an embodiment of the present invention includes: a clamping unit fixing a central portion of a material and exposing both ends that are locally heated; A hole penetrating through the material in the axial direction and having a first inlet in the direction of the clamping unit and a second inlet opposite to the first inlet is provided, and is disposed on both sides of the clamping unit to move forward and backward to the clamping unit. shaft tube mold; and a mandrel disposed on both sides of the shaft tube mold to move forward and backward toward the second inlet of the hole of the shaft tube mold.

According to an exemplary embodiment, the clamping unit may include a stationary mold having a groove corresponding to the shape of the material, and a movable mold having a groove corresponding to the shape of the material and selectively contacting the stationary mold. have.

According to an exemplary embodiment, the first inlet portion and the second inlet portion of the shaft tube mold may be tapered.

According to an exemplary embodiment, it may further include a heating unit for heating both ends of the material.

According to an exemplary embodiment, the heating unit may include a coil that can be drawn in and out from both ends of the material, and a high-frequency heater electrically connected to the coil.

The drive shaft for a vehicle according to an embodiment of the present invention may be manufactured by the above-described apparatus for manufacturing a drive shaft for a vehicle.

A method of manufacturing a drive shaft for a vehicle according to an embodiment of the present invention includes a fixing step of fixing a central portion of a material and exposing both ends that are locally heated; A shaft pipe step of first thickening both ends of the material by shunting both ends of the material; and by upsetting both ends of the material, an upsetting step of secondarily thickening both ends of the material.

According to an exemplary embodiment, in the shaft tube step, the shaft tube mold having a hole corresponding to the material advances to the material, and both ends of the material are inserted into the hole of the shaft tube mold to be performed.

According to an exemplary embodiment, the upsetting step may be performed by advancing the mandrel to the material through the hole of the shaft tube mold.

Each feature of the above-described embodiments may be implemented in combination in other embodiments as long as they are not contradictory or exclusive to other embodiments.

The present invention described above has the following effects.

According to an embodiment of the present invention, both ends of the material are primarily thickened in the shaft tube step, and both ends of the material are secondarily thickened in the upsetting step. Therefore, in the embodiment of the present invention, it is possible to effectively obtain a desired amount of thickening at both ends of the material.

According to the embodiment of the present invention, since a desired amount of thickening can be effectively obtained at both ends of the material, unnecessary amount of thickening can be minimized. Therefore, post-processing is efficient and material loss can be reduced.

According to the embodiment of the present invention, it is possible to improve the disadvantages of the swaging method, that is, the limitation of the amount of thickening at both ends of the material, and the disadvantages of the upsetting method, that is, the occurrence of unnecessary thickening.

According to an embodiment of the present invention, it is possible to manufacture a drive shaft for a vehicle by performing the shaft pipe step and the upsetting step substantially simultaneously. Therefore, in the embodiment of the present invention, the manufacturing process can be simplified.

1 is a cross-sectional view schematically showing an embodiment of a heating unit of an apparatus for manufacturing a drive shaft for a vehicle according to the present invention.

2 is a cross-sectional view schematically illustrating an embodiment of an apparatus for manufacturing a drive shaft for a vehicle according to the present invention.

3 to 9 are cross-sectional views schematically illustrating an embodiment of a method for manufacturing a drive shaft for a vehicle according to the present invention.

10 is a cross-sectional view schematically illustrating an embodiment of a drive shaft for a vehicle according to the present invention.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described.

The embodiments described below are provided to help the understanding of the present invention, and therefore the present invention is not limited to the embodiments described below. In addition, in the accompanying drawings, specific components may be exaggerated or reduced in order to facilitate understanding of the present invention, and the present invention is not limited to the form drawn in the drawings.

In order to avoid complicated description, detailed descriptions of the same components as in the prior art among the components of the present embodiment will be omitted, and descriptions will be made mainly on contents related to the subject matter of the present embodiment.

The present invention may largely include a heating step of heating the material for making the drive shaft, and a thickening step of increasing the thickness of both ends of the material. The thickening step may include a shaft tube step and an upsetting step.

First, an embodiment of the heating step of the method for manufacturing a drive shaft for a vehicle according to the present invention will be described with reference to FIG. 1 .

The heating step is a process of locally heating both ends 34 located on the left and right of the central portion 32 of the material 3 . The material 3 may be a hollow material 3 . The material 3 may be a hollow round bar, a pipe, or the like.

Both ends 34 of the material 3 may be heated by a high-frequency heating method. A high-frequency heating unit may be used to heat both ends 34 of the material 3 by a high-frequency heating method. The high frequency heating unit may include a coil 5 and a high frequency heater (not shown) connected to the coil 5 .

As shown in Figure 1 (a), the coil (5) may be located spaced apart a predetermined distance on the left and right sides of the material (3).

As shown in Figure 1 (b), in order to locally heat the both ends 34 of the material 3, the coil 5 may be advanced in the direction of both ends 34 of the material 3 to be drawn in.

Since both ends 34 of the material 3 are locally heated, the coil 5 may be located at both ends 34 without entering the central portion 32 of the material.

When the high-frequency heater operates in this state, the coil 5 generates heat, and both ends 34 of the material 3 can be locally heated. When the heating of both ends 34 of the material 3 is completed, the coil 5 may move backward and return to its original position.

On the other hand, both ends 34 of the heated material 3 may be increased in thickness by the thickening step. The thickening step of this embodiment may include a shaft tube step and an upsetting step.

First, an embodiment of an apparatus for manufacturing a drive shaft for a vehicle according to the present invention will be described with reference to FIG. 2 . Hereinafter, a manufacturing apparatus mainly used in the thickening step is referred to as a 'thickening apparatus' for convenience.

The thickening apparatus may include a clamping unit 5 , a shaft tube mold 7 , and a mandrel 9 . The clamping unit 5 is a device for fixing the material 3 so that it does not move. The shaft tube mold 7 is a device for primarily thickening the both ends 34 of the raw material 3 . The mandrel 9 is a device for secondary thickening of both ends 34 of the material 3 .

On the left and right sides of the clamping unit 5, the shaft tube mold 7 may be located spaced apart by a predetermined distance. The shaft tube mold 7 can move forward and backward in the direction of the clamping unit 5 .

The mandrel 9 may be located on the left and right sides of the shaft tube mold 7 spaced apart by a predetermined distance. The mandrel 9 can move back and forth in the direction of the shaft tube mold 7 .

The clamping unit 5, the shaft tube mold 7, and the mandrel 9 will be described in detail.

The clamping unit 5 will be described.

The clamping unit 5 may include a stationary mold 52 and a movable mold 54 . The material 3 may be placed on the stationary mold 52 . To this end, a groove 522 corresponding to the shape of the material 3 may be provided on the upper surface of the stationary mold 52 . The cross section of the groove 522 may be semi-circular. The radius of the groove 522 may be the same as the radius of the material 3 .

The movable mold 54 may be approached or retracted to the stationary mold 52 to fix or release the fixing of the material 3 . The movable mold 54 can be moved vertically or horizontally in a horizontal or vertical press manner. A groove 542 corresponding to the shape of the material 3 may be provided on the lower surface of the movable mold 54 . The cross section of the groove 542 may be semicircular. The radius of the groove 542 may be the same as the radius of the material 3 .

Next, the shaft tube die 7 is demonstrated.

The shaft tube mold 7 may be positioned on the left and right sides of the clamping unit 5 , and may advance or retreat in the direction of the clamping unit 5 .

The shaft tube mold 7 may be provided with a hole 72 penetrating the inside. The hole 72 may have a small diameter cylindrical shape. The direction of the hole 72 may correspond to the axial direction of the material 3 . The diameter of the hole 72 may be smaller than the outer diameter of the material 3 .

A diameter of the first inlet 74 at the front of the hole 72 (in a direction adjacent to the clamping unit) may be larger than a diameter of the hole 72 . The first inlet 74 may have a tapered shape. For example, the diameter of the first inlet portion 74 may become smaller toward the inside of the shaft tube mold 7 .

The diameter of the second inlet 76 at the rear of the hole 72 (opposite the first inlet 74 ) may be larger than the diameter of the hole 72 . The second inlet 76 may have a tapered shape. For example, the diameter of the second inlet portion 76 may become smaller toward the inside of the shaft tube mold 7 .

The mandrel 9 will be described.

The mandrel 9 is located on the left and right sides of the shaft tube mold 7 , and may advance or retreat in the direction of the shaft tube mold 7 .

The mandrel 9 may include a body 92 and a protrusion 94 connected to the body 92 . The direction of movement of the mandrel 9 may correspond to the axial direction of the material 3 . The diameter of the protrusion 94 may be smaller than the inner diameter of the material 3 . The diameter of the body portion 92 may be greater than the inner diameter of the material 3 , and may be substantially the same as the inner diameter of the hole 72 of the shaft tube mold 7 .

An embodiment of a method of manufacturing a drive shaft will be described with reference to FIGS. 2 to 5 .

As described above, both ends 34 of the material 3 may be locally heated by the coil 5 . A fixing step in which both ends 34 are fixed to the heated material 3 will be described.

As shown in FIG. 2 , the central portion 32 of the material 3 may be placed in the groove 522 of the stationary mold 52 of the clamping unit 5 . That is, the material 3 having both ends 34 locally heated is transferred to the stationary mold 52 so that the unheated central part 32 of the material 3 is placed in the groove 522 of the stationary mold 52 . can

As shown in FIG. 3 , the movable mold 54 may move in the direction of the stationary mold 52 to press and fix the central portion 32 of the material 3 .

When the fixing step is completed, the central portion 32 of the material 3 is press-fixed by the clamping unit 5 , and both ends 34 may be exposed to the outside of the clamping unit 5 . In this state, the thickening step, that is, the shaft tube step and the upsetting step may be performed substantially simultaneously.

With reference to FIGS. 3 to 5 , a shaft pipe step in which both ends 34 of the material 3 are primarily thickened will be described.

As shown in FIG. 3 , when the material 3 is fixed to the clamping unit 5 , the shaft tube mold 7 can approach the clamping unit 5 in the direction, that is, the material 3 . When the shaft tube mold 7 advances to the clamping unit 5 , both ends 34 of the raw material 3 are inserted into the first inlet 74 of the shaft tube mold 7 .

As shown in FIG. 4 , both ends 34 of the material 3 may be thickened while moving to the hole 72 past the first inlet 74 of the shaft tube mold 7 .

The outer diameter of both ends 34 of the material 3 may be gradually reduced by the inclined surface of the first inlet 74 of the shaft tube mold 7 . Both ends 34 of the material 3 passing through the first inlet 74 may have a smaller diameter and increased thickness as they pass through the hole 72 of the shaft tube mold 7 . Since the end of the material 3 is in a heated state, it can be more easily thickened.

As shown in FIG. 5 , when the shaft tube mold 7 comes into contact with the clamping unit 5 , the movement of the shaft tube mold 7 may be stopped.

In FIGS. 4 and 5 , both ends 34 having a reduced diameter and increased thickness are indicated by reference numerals '342' for convenience.

In a state in which the primary thickening is completed, the outer diameter and inner diameter of both ends 342 of the material 3 may be in a reduced state. In addition, between the central portion 32 and the both ends 342 of the material 3 344 may be slightly inclined.

An upsetting step in which both ends 34 of the material 3 are secondarily thickened will be described with reference to FIGS. 5 to 7 .

The upsetting step may be performed substantially simultaneously with the shaft tube step. That is, the shaft tube mold 7 advances in the direction of the material 3, the material 3 is inserted into the first inlet 74 of the shaft tube mold 7, and at the same time, the second inlet of the shaft tube mold 7 ( 76) direction the mandrel 9 may advance.

As shown in FIG. 5 , the shaft tube mold 7 comes into contact with the clamping unit 5 in the shaft tube step, so that the movement of the shaft tube mold 7 can be stopped. In this state, the mandrel 9 may continue to advance and be inserted into the second inlet 76 of the shaft tube mold 7 .

As shown in FIG. 6 , the mandrel 9 inserted into the second inlet 76 of the axial tube mold 7 can continue to advance. The diameter of the protrusion 94 of the mandrel 9 may be smaller than the inner diameter of the material 3 that has undergone the shaft tube step. Accordingly, when the mandrel 9 continues to advance toward the center of the hole 72 , the protrusions 94 of the mandrel 9 may be inserted into the hollows of the both ends 342 of the material 3 .

With the mandrel 9 inserted into the hollow of both ends 342 of the material 3, when the mandrel 9 advances further, the body portion 92 of the mandrel 9 continues the both ends 342 of the material 3 can push Accordingly, at both ends 342 of the material 3, the material 3 is compressed in the axial direction, and as the flow of the material 3 moves to the inner surface, it comes into contact with the mandrel 9 to increase the thickness. Since both ends 342 of the material 3 are in a heated state, thickening is easier.

In FIG. 6 , for convenience, both ends 34 that are first thickened are denoted by reference numeral '342', and both ends 34 that are secondly thickened are denoted by reference numeral '346'. As shown in FIG. 6 , the thickness of the second thickened both ends 346 is greater than the thickness of the first thickened both ends 342 .

7 shows a state in which the secondary thickening is completed.

The outer diameter of both ends 346 of the material 3 in the state in which the secondary thickening is completed may be the same as the outer diameter of the both ends 342 of the material 3 in which the primary thickening is completed. Because, even in the second thickening step, both ends 342 of the first thickened material 3 are located in the hole 72 of the shaft tube mold 7 . Therefore, since the outer diameter of both ends 342 of the primary thickened material 3 is prevented from expanding in the outer radial direction by the hole 72 of the shaft tube mold 7, the outer diameter of both ends 342 can be changed because there is no

On the other hand, the inner diameter of both ends 346 of the material 3 in the state in which the secondary thickening is completed may be smaller than the inner diameter of the both ends 342 of the material 3 in which the primary thickening is completed. Because the outer diameter of the protrusion 94 of the mandrel 9 is smaller than the inner diameter of both ends 342 of the material 3 on which the primary thickening has been completed, both ends 342 of the material 3 on which the primary thickening is completed are formed by the mandrel ( This is because it is thickened in the direction of the protrusion 94 of 9).

Accordingly, the thickness of both ends 346 of the material 3 in which the secondary thickening is completed may be greater than the thickness of both ends 342 of the material 3 in which the primary thickening is completed.

With reference to FIGS. 8 to 9 , taking out the thickened material 3 will be described.

As shown in FIG. 8 , first, the mandrel 9 can be separated from the shaft tube mold 7 . As shown in FIG. 9 , the shaft tube mold 7 can then be separated from the clamping unit 5 . Then, the movable mold 54 may be separated from the stationary mold 52 of the clamping unit 5 . Then, the thickened material 3 can be taken out from the stationary mold 52 .

10 is a drive shaft separated from the stationary mold 52 .

The outer diameter/inner diameter of both ends 346 of the material 3 is smaller than the outer diameter/inner diameter of the central part 32 . The thickness of both end portions 346 of the material 3 is greater than the thickness of the central portion 32 .

The effect of the drive shaft for a vehicle, the manufacturing apparatus thereof, and the manufacturing apparatus according to the embodiment of the present invention described above will be described as follows.

According to an embodiment of the present invention, the shaft tube step and the upsetting step may be performed substantially simultaneously to obtain a desired increase in weight. Therefore, in the present embodiment, unnecessary thickening can be avoided and thus material loss can be minimized in the post-processing of the drive shaft.

Because, if only the shaft tube step is performed, the outer diameter of both ends of the material becomes smaller and the length becomes longer, so there is a limit to the increase in thickness. However, in this embodiment, the upsetting step is performed after the shaft pipe step. Therefore, while maintaining the outer diameter of both ends of the material reduced in the shaft tube step as it is, the elongated portion is compressed to increase both ends of the material in the inner diameter direction. Accordingly, it is possible to effectively obtain a desired amount of material to be thickened.

According to an embodiment of the present invention, it is possible to solve the disadvantages of the conventional swaging method and the upsetting method. Because, when only the conventional swaging method is used, there is a limit to the increase in the thickness of both ends of the material, and several steps are required. In the case of using only the conventional upsetting method, unnecessary thickening of both ends of the material occurs and a process of several steps is required.

However, in this embodiment, the shaft tube step once and the upsetting step once are substantially simultaneously performed, thereby simplifying the process while obtaining a desired thickening amount. In addition, in this embodiment, since the shaft pipe step is performed by locally heating both ends of the material, it is possible to improve the disadvantages of the conventional cold forging method.

As described above, the present invention has been described with reference to examples and drawings, which are used to help the understanding of the present invention. Accordingly, the present invention is not limited to the embodiments described above. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art to which the present invention pertains, and these modifications and variations are also within the scope of the present invention.

The present invention can be applied to a method of manufacturing a drive shaft for an automobile by performing the shaft pipe step and the upset step substantially simultaneously.

Claims

a clamping unit that fixes the central part of the material and exposes both ends that are locally heated;

A hole penetrating through the material in the axial direction and having a first inlet in the direction of the clamping unit and a second inlet opposite to the first inlet is provided, and is disposed on both sides of the clamping unit to move forward and backward to the clamping unit. shaft tube mold; and

An apparatus for manufacturing a drive shaft for a vehicle including a mandrel disposed on both sides of the shaft tube mold and capable of moving forward and backward toward the second inlet of the hole of the shaft tube mold.
According to claim 1,

The clamping unit may include a fixed mold having a groove corresponding to the shape of the material, and a moving mold having a groove corresponding to the shape of the material and selectively contacting the fixed mold. of manufacturing equipment.
3. The method of claim 1 or 2,

The manufacturing apparatus of a drive shaft for a vehicle, characterized in that the first inlet portion and the second inlet portion of the shaft mold is tapered.
4. The method of claim 3,

The apparatus for manufacturing a drive shaft for a vehicle, characterized in that it further comprises a heating unit for heating both ends of the material.
5. The method of claim 4,

The heating unit, the manufacturing apparatus of a drive shaft for a vehicle, characterized in that it comprises a coil that can be drawn in and out from both ends of the material, and a high-frequency heater electrically connected to the coil.
A drive shaft for a vehicle manufactured by the apparatus for manufacturing a drive shaft for a vehicle according to any one of claims 1 to 5.
A fixing step of fixing the central portion of the material and exposing both ends that are locally heated;

A shaft pipe step of primarily thickening both ends of the material by squeezing both ends of the material; and

A method of manufacturing a drive shaft for a vehicle comprising an upsetting step of upsetting both ends of the material to secondarily thicken both ends of the material.
8. The method of claim 7,

The shaft tube step, the shaft tube mold having a hole corresponding to the material advances to the material, and both ends of the material are inserted into the hole of the shaft tube mold.
9. The method of claim 8,

The upsetting step is a method of manufacturing a drive shaft for a vehicle, characterized in that the mandrel is carried out by advancing to the material through the hole of the shaft tube mold.