EP3456430B1

EP3456430B1 - Apparatus for manufacturing tube yoke

Info

Publication number: EP3456430B1
Application number: EP16901783.7A
Authority: EP
Inventors: Tae-min HWANG; Sang-Gyun Park
Original assignee: Sungjin Fo-Ma Inc
Current assignee: Sungjin Fo-Ma Inc
Priority date: 2016-05-09
Filing date: 2016-10-18
Publication date: 2022-08-31
Anticipated expiration: 2036-10-18
Also published as: EP3456430A4; CN107708889B; EP3456430A1; WO2017195950A1; CN107708889A; KR101685496B1

Description

TECHNICAL FIELD

The present invention relates to a tube yoke manufacturing apparatus, and more particularly, to a tube yoke manufacturing apparatus in which a tube yoke having a spline in a tube part through a forging process can be quickly manufactured and the shape of the spline may be prevented from being distorted.

BACKGROUND ART

Typical yokes are configured to smoothly transmitting power of a main driving shaft to a driven shaft when the driven shaft is disposed not collinear with a rotating main shaft but inclined by a predetermined angle, or disposed collinear with respect to the main shaft, as in cases of steering a vehicle, a propulsion shaft for transmitting power of an engine, or the like.
FIG. 1 is a perspective view of a typical tube yoke, and the tube yoke includes a yoke part 2, and a shaft 3 coupled to a lower portion of the yoke part 2.
In case of typical tube yokes, the yoke part 2 and a shaft 3 are separately manufactured, and then the lower portion of the yoke part 2 and an upper portion of the shaft 3 are welded to thereby manufacture the tube yoke.
However, as described above, the tube yoke which is manufactured by welding the yoke part and the shaft has a difficulty in that a knuckle part and the shaft should be manufactured by separate apparatuses. Accordingly, there have been problems in that equipment cost is increased, deformation such as distortion of the knuckle part or the shaft may be caused due to heat during welding, and welded portions are weak and therefore, are not sturdy to be used.
To solve the above-described problems, a tube yoke in which the yoke part and the shaft part are integrally formed has already been disclosed.
However, in case of the tube yoke in which the yoke part and the shaft part are integrally formed, it is difficult to form a spline in an inner surface of the tube yoke, and thus there is a limitation in that an additional process such as correction after forming the spline is necessary.
In addition, as described above, due to the difficulty in forming the spline, there is a case in which the tube yoke in which the yoke part and the shaft part are integrally formed are manufactured through a forging process, and the spline formation is performed through a separate machining process, but this causes limitations in that not only a manufacturing time is increased excessively, but also a manufacturing cost is increased.
An apparatus comprising the features of the preamble portion of claim 1 is known from WO 2008/091134 . The tube yoke is formed by several moulds to thereby form a semi-finished product having an inner diametric hole. Subsequently, inner splines are formed inside the inner diametric hole by means of a mandrel, which is said to repeatedly strike the inner diameter surface inner diametric hole using a high-speed rotating cam.
Further apparatus for making inner splines are known from KR 101 255 809 B1 and JP S61 201926 A , which, however, do not teach inserting a mandrel for forming the spline but suggest extruding material of a semi-finished product along a splined core.

DISCLOSURE OF THE INVENTION

TECHNICAL PROBLEM

The purpose of the present invention is to provide a tube yoke manufacturing apparatus in which a tube yoke having a spline in a tube part through a forging process can be quickly manufactured and the shape of the spline may be prevented from being distorted.

TECHNICAL SOLUTION

This technical problem is solved by an apparatus as defined by claim 1.
Advantageous embodiments are indicated in further claims.
A land part protruding in a circumferential direction of the forming pin is formed on the spline part corresponding to one side in the length direction of the forming pin.
The land part may include: a first land part formed on an end portion at the one side of the forming pin in the lengthwise direction of the forming pin; and a second land part formed at a position spaced apart from the first land part toward the other side.
A protruding height of the first land part may be formed to be greater than that of the second land part.
A length of the spline part of the forming pin may be formed greater than a depth of the inner diametric hole of the tube part.
The plurality of tube yoke forming moulds may include: a central groove forming mould including a central groove forming die receiving a cut material and a punch pressing one side of the material supplied to the central groove forming die to form a central groove in one side of the material; a first backward extrusion mould including a first backward extrusion die disposed next to the central groove forming die to receive a material and a die pin pressing the material supplied to the first backward extrusion die to thereby form a tube part in which an inner diametric hole is formed in one side of the material through backward extrusion; a second backward extrusion mould including a second backward extrusion die disposed next to the first backward extrusion die to receive a material and a die pin inserted into the inner diametric hole of the material supplied to the second backward extrusion die to thereby form the tube part through backward extrusion such that the length of the tube part is increased; a preliminary yoke forming mould including a preliminary yoke forming die disposed next to the second backward extrusion die to receive a material and a punch pressing the material supplied to the preliminary yoke forming die to thereby form a preliminary yoke part in which a guide groove is formed on the other side of the material; and a yoke forming mould including a yoke forming die disposed next to the preliminary yoke forming die to receive a material and a punch pressing the material supplied to the yoke forming die to thereby form a yoke part, and the spline forging mould may include: a spline forming die disposed next to the yoke forming die to receive a material; and a forming pin inserted into the tube part and having a spline part formed on an outer circumferential surface thereof so as to form a spline inside the tube part.
Materials to be formed may be respectively supplied to the central groove forming mould, the first backward extrusion mould, the second backward extrusion mould, the preliminary yoke forming mould, the yoke forming mould, and the spline forming mould; the forming operations of the central groove forming mould, the first backward extrusion mould, the second backward extrusion mould, the preliminary yoke forming mould, the yoke forming mould, and the spline forming mould may be configured to be simultaneously performed together; and a plurality of materials which are completely formed in respective moulds may be moved and supplied together at once to the moulds of the next processes.

ADVANTAGEOUS EFFECTS

As described above, the present invention has a merit in that a tube yoke in which a spline formed in a tube part through a forging process may be quickly manufactured.
In addition, there is a merit in that the shape of the spline may be prevented from being distorted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a typical tube yoke.
FIG. 2 is a view illustrating a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 3 is a view illustrating a central groove forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 4 is a view illustrating a first backward extrusion mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 5 is a view illustrating a second backward extrusion mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 6 is a view illustrating a preliminary yoke forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 7 is a view illustrating a yoke forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 8 is a view illustrating a spline forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIGS. 9 to 11 are views illustrating a process in which a spline is formed through a spline forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 12 is a view illustrating a forming pin provided in a spline forming mould of a tube yoke manufacturing apparatus according to an embodiment of the present invention.
FIG. 13 is a cross-sectional view taken along line A-A' of FIG. 12.

MODE FOR CARRYING OUT THE INVENTION

The present invention may be implemented as various forms without departing from the scope of the invention as defined by the appended claims. Thus, the embodiment of the present invention is merely an exemplification in all aspects, and should not be limitatively interpreted.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Like reference numerals denote like elements in the same or corresponding components regardless of reference numerals, and overlapping descriptions thereof will not be provided.
Moreover, detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present invention.
As illustrated in FIG. 2, a tube yoke manufacturing apparatus A according to an embodiment of the present invention includes a central groove forming mould 110, a first backward extrusion mould 120, a second backward extrusion mould 130, a preliminary yoke forming mould 140, a yoke forming mould 150, and a spline forming mould 160.
Materials to be formed are respectively supplied to the central groove forming mould 110, the first backward extrusion mould 120, the second backward extrusion mould 130, the preliminary yoke forming mould 140, the yoke forming mould 150, and the spline forming mould 160 which are described above, and simultaneously formed together.
For example, a first material is formed in the central grove forming mould 110 and is then supplied to the first backward extrusion mould 120 through a conveying device. At this time, a new second material is simultaneously supplied together with the movement of the first material.
In addition, the first material is formed in the first backward extrusion mould 120 and is then supplied to the second backward extrusion mould 130. At this time, together with the movement of the first material, not only the second material is simultaneously supplied to the first backward extrusion mould 120, but also a new third material is simultaneously supplied to the central groove forming mould 110.
As described above, not only one material is simultaneously formed together while being sequentially conveyed to the central groove forming mould 110, the first backward extrusion mould 120, the second backward extrusion mould 130, the preliminary yoke forming mould 140, the yoke forming mould 150, and the spline forming mould 160, but also materials are continuously supplied and formed.
That is, the central groove forming mould 110, the first backward extrusion mould 120, the second backward extrusion mould 130, the preliminary yoke forming mould 140, the yoke forming mould 150, and the spline forming mould 160, which are described above, are configured such that forming operations thereof are simultaneously performed together, and in addition, are configured such that a plurality of materials which are completely formed in respective moulds are simultaneously moved and supplied together to moulds of next processes through respective conveying apparatuses.
As described above, since the materials are continuously supplied and the forming operations of the central groove forming mould 110, the first backward extrusion mould 120, the second backward extrusion mould 130, the preliminary yoke forming mould 140, the yoke forming mould 150, and the spline forming mould 160 are simultaneously performed together and thus all forming operations are performed at once, the tube yoke manufacturing apparatus A according to an embodiment of the present invention may manufacture one final product for every one cycle operation thereof (one operation in which a punch is moved to a die to form a material and is then retracted).
Hereinafter, structures of the central groove forming mould 110, the first backward extrusion mould 120, the second backward extrusion mould 130, the preliminary yoke forming mould 140, the yoke forming mould 150, and the spline forming mould 160 will be described in brief.
As illustrated in FIG. 3, the central groove forming mould 110 includes: a central groove forming die 111 receiving a cut material; and a punch 113 which presses one side of the material supplied to the central groove forming die 111 to thereby make a central groove formed at the one side of the material.
The central groove may be formed through a die pin 111P provided in the central groove forming die 111.
When the central groove forming mould 110 performs one cycle of operations, the central groove is formed in the one side of the material.
As illustrated in FIG. 2, the first backward extrusion mould 120 is disposed next to the central groove forming mould 110, and as illustrated in FIG. 4, includes: a first backward extrusion die 121 receiving the material formed through the central groove forming mould 110 through a separate conveying device (not shown); and a die pin 121P which presses the material supplied to the first backward extrusion die 121 to thereby form a tube part, in which an inner diametric hole is formed, through a backward extrusion.
The first backward extrusion may be performed as a punch 123 presses the upper portion of the material.
When the first backward extrusion mould 120 performs one cycle of operations, the tube part in which an inner diametric hole is formed in one side of the material may be formed through backward extrusion.
As illustrated in FIG. 2, the second backward extrusion mould 130 is disposed next to the first backward extrusion mould 120, and as illustrated in FIG. 5, includes: a second backward extrusion die 131 receiving the material formed through the first backward extrusion mould 120 through a separate conveying device (not shown); and a die pin 131P which is inserted into the inner diametric hole of the material supplied to the second backward extrusion die 131 to thereby form a tube part through a backward extrusion such that the length of the tube part is increased.
The second backward extrusion may be performed as a punch 133 presses the upper portion of the material.
When the second backward extrusion mould 130 performs one cycle of operations, the tube part may be formed through backward extrusion such that the length of the tube part is increased.
As illustrated in FIG. 2, the preliminary yoke forming mould 140 is disposed next to the second backward extrusion mould 130, and as illustrated in FIG. 6, includes: a preliminary yoke forming die 141 receiving the material formed through the second backward extrusion mould 130 through a separate conveying device (not shown); and a punch 143 which presses the material supplied to the preliminary yoke forming die 141 to thereby form a preliminary yoke part in which a guide groove is formed in the other side of the material.
Meanwhile, the preliminary yoke forming die 141 is provided with a die pin 141P inserted into the inner diametric hole.
When the preliminary yoke forming mould 140 performs one cycle of operations, the preliminary yoke part for forming a yoke part in the other side of the material may be formed.
As illustrated in FIG. 2, the yoke forming mould 150 is disposed next the preliminary yoke forming mould 140, and as illustrated in FIG. 7, includes: a yoke forming die 151 receiving the material formed through the preliminary yoke forming mould 140 through a separate conveying device (not shown); and a punch 153 which presses the material supplied to the yoke forming die 151 to thereby form a yoke part.
Meanwhile, the yoke forming mould 150 is provided with a die pin 151P for completing the shape of the inner diametric hole by being inserted into the inner diametric hole.
When the yoke forming mould 150 performs one cycle of operations, the yoke part may be formed in the other side of the material.
As illustrated in FIG. 2, the spline forming mould 160 is disposed next the yoke forming mould 150, and as illustrated in FIG. 8, includes: a spline forming die 161 receiving the material formed through the yoke forming mould 150 through a separate conveying device (not shown); and a forming pin 161P in which a spline part 161P-a is formed in an outer circumferential surface of the forming pin such that the forming pin is inserted into the tube part so as to form a spline SP inside the tube part.
When the spline forming mould 160 performs one cycle of operations, the spline SP may be formed inside the tube part of the material.
More specifically, the spline forming mould 160, as illustrated in FIG. 9, the length of the spline part 161P-a of the forming pin 161P is formed to be greater than the depth of the inner diametric hole of the tube part.
In addition, in a cross-section of the spline part 161P-a of the forming pin 161P, concave recesses and convex protrusions are alternately formed, and in particular, land parts L1 and L2 which protrude in the circumferential direction of the spline part are formed on the spline part 161P-a corresponding to one side in the lengthwise direction of the forming pin 161P.
Specifically, as illustrated in FIGS. 12 and 13, the land parts L1 and L2 include: a first land part L1 formed on an end part at the one side in the lengthwise direction of the forming pin 161P; and a second land part L2 formed at a position spaced apart from the first land part L1 toward the other side, wherein the protruding height of the first land part L1 is formed greater than that of the second land part L2.
For example, when the forming pin 161P is completely inserted into the tube part and retracted to thereby form a spline SP, there may be a portion with a load below a yield strength in the inner portion of the tube part, and such the portion still remains within an elastic region, thereby having a property of returning to an original shape. For such reason, there is a limitation in that the shape of the spline SP may not be formed satisfactory.
The first land part L1 functions to make the portion, remaining in the elastic region, subjected to a plastic deformation such that in a process in which the spline SP is formed as the forming pin 161P is inserted into the tube part, a portion of the material inside the tube part remains in the elastic region to be thereby partially returned to the original shape, and during the retraction process, the portion is deformed by an applied force such that the spline shape with a desired dimension is formed again.
Specifically, as the forming pin 161P is inserted into the tube part, a portion of the material is partially returned to a diametric part ("R" of FIG. 13) lower than the protruding height of the first land part L1. However, in the retraction process of the forming pin 161P, the partially returned portion is pressed again to be thereby subjected to plastic deformation.
That is, in a structure without the first land part L1, when the forming pin 161P is inserted into the tube part and is then retracted, a portion of the material is under a load below the yield strength to be thereby partially returned to the original shape, and thus, unsatisfactory spline may be formed. However, as the first land part L1 is formed, deformation is applied such that the spline is formed two times to make plastic deformation performed on entire portions. Thus, a satisfactory shape of the spline SP may be formed.
Meanwhile, the second land part L2 functions to guide the retraction of the forming pin 161P in a state of being inserted into the spline part 161P-a formed by the first land part L1 when the forming pin 161P is inserted into the tube part and then retracted. The shape of the spline SP may be formed more satisfactory by means of the second land part L2.
Hereinafter, a tube yoke manufacturing method using the above-mentioned tube yoke manufacturing apparatus A will be described.
A tube yoke manufacturing method according to an embodiment of the present invention includes a tube yoke forging process S100 and a spline forging process S200.
The tube yoke forging process S100 is a process in which a material is inserted into a die, and is then pressed by a punch to thereby form a tube yoke including a tube part and a yoke part. The tube yoke forging process S100 may include, for example, a central groove forming process S110, a first backward extrusion process S120, a second backward extrusion process S130, a preliminary yoke forming process S140, and a yoke forming process S150.
First, the tube yoke forging process S100 including the central groove forming process S110, the first backward extrusion process S120, the second backward extrusion process S130, the preliminary yoke forming process S140, and the yoke forming process S150 will be described.
The central groove forming process S110 is a process in which a cut material is supplied to a central groove forming die and then punched such that a central groove is formed in one side of the material.
For example, the central groove forming process S110 may be performed through the above-described central groove forming mould 110.
The first backward extrusion process S120 is a process in which the material is supplied to a first backward extrusion die, and a die pin is moved forward to form a tube part in which an inner diametric hole is formed in one side of the material.
For example, the first backward extrusion process S120 may be performed through the first backward extrusion mould 120.
The second backward extrusion process S130 is a process in which the material is supplied to a second backward extrusion die, and a die pin is moved forward to form the tube part such that the length of the tube part at the one side of the material is increased.
For example, the second backward extrusion process S130 may be performed through the second backward extrusion mould 130.
The preliminary yoke forming process S140 is a process in which the material is supplied to a preliminary yoke forming die and then pressed by a punch to form a preliminary yoke part in which a guide groove is formed in one side of the material.
For example, the preliminary yoke forming process S140 may be performed through the above-described preliminary yoke forming mould 140.
The yoke forming process S150 is a process in which the material is supplied to a yoke forming die and then pressed by a yoke forming punch to form a yoke part and completely form the inner diametric hole by means of a die pin.
For example, the yoke forming process S150 may be performed through the above-described yoke forming mould 150.
As described above, the tube yoke including the tube part and the yoke part may be formed through the tube yoke forging process S100 including the central groove forming process S110, the first backward extrusion process S120, the second backward extrusion process S130, the preliminary yoke forming process S140, and the yoke forming process S150.
The spline forging process S200 is performed after the tube yoke forging process S100, and specifically, the spline forging process S200 is a process in which a forming pin 161P having a spline part 161P-a in an outer circumferential surface thereof is inserted into the tube part of tube yoke to form a spline SP inside the tube part.
For example, the spline forging process S200 may be performed through the above-described spline forming mould 160.
In a cross-section of the spline part 161P-a of the forming pin 161P, concave recesses and convex protrusions are alternately formed, and land parts L1 and L2 protruding in the circumferential direction of the forming pin are formed on the spline part 161P-a corresponding to one side in the lengthwise direction of the forming pin 161P.
Specifically, the land parts L1 and L2 includes: a first land part L1 formed on an end part at the one side in the lengthwise direction of the forming pin 161P; and a second land part L2 formed at a position spaced apart from the first land part L1 toward the other side, wherein the protruding height of the first land part L1 is formed greater than that of the second land part L2.
Also, the length of the spline part 161P-a of the forming pin 161P may be formed greater than the depth of the inner diametric hole in the tube part.
Since the shapes of the land parts L1 and L2 of the forming pin 161P and the length of the spline part 161P-a have been already described above, detailed descriptions thereof will not be provided.
While exemplary embodiments of the present invention are described with reference to the accompanying drawings, it will be clarified that various and obvious modifications can be made from the description herein by those skilled in the art without departing the scope of the claims.

Claims

A tube yoke manufacturing apparatus (A) comprising:
a plurality of tube yoke forming moulds (110-150) configured to form a tube yoke comprising a tube part (3) and a yoke part (2) by inserting a material into a die and pressing the material by means of a punch, and

a spline forging mould (160) provided with a forming pin (161P) having a spline part (161P-a) formed in an outer circumferential surface thereof and configured to make a spline (SP) formed inside the tube part (3) as the forming pin (161P) is inserted into the tube part (3)

characterized in that

a land part (L1, L2) protruding in a circumferential direction of the forming pin (161P) is formed on the spline part (161P-a) corresponding to one side in the length direction of the forming pin.
The tube yoke manufacturing apparatus of claim 1, wherein the land part comprising: a first land part (L1) formed on an end portion at the one side of the forming pin (161P) in the lengthwise direction of the forming pin (161P); and a second land part (L2) formed at a position spaced apart from the first land part (L1) toward the other side.
The tube yoke manufacturing apparatus of claim 2, wherein a protruding height of the first land part (L1) is formed to be greater than that of the second land part (L2).
The tube yoke manufacturing apparatus of one of claims 1 to 3, wherein the plurality of tube yoke forming moulds comprises:
a central groove forming mould (110) comprising a central groove forming die receiving a cut material and a punch pressing one side of the material supplied to the central groove forming die to form a central groove in one side of the material;

a first backward extrusion mould (120) comprising a first backward extrusion die disposed next to the central groove forming die to receive a material and a die pin pressing the material supplied to the first backward extrusion die to thereby form a tube part in which an inner diametric hole is formed in one side of the material through backward extrusion;

a second backward extrusion mould (130) comprising a second backward extrusion dice disposed next to the first backward extrusion die to receive a material and a die pin inserted into the inner diametric hole of the material supplied to the second backward extrusion die to thereby form the tube part through backward extrusion such that the length of the tube part is increased;

a preliminary yoke forming mould (140) comprising a preliminary yoke forming die disposed next to the second backward extrusion die to receive a material and a punch pressing the material supplied to the preliminary yoke forming die to thereby form a preliminary yoke part in which a guide groove is formed on the other side of the material; and

a yoke forming mould (150) comprising a yoke forming die disposed next to the preliminary yoke forming die to receive a material and a punch pressing the material supplied to the yoke forming die to thereby form a yoke part,

wherein the spline forging mould (160) comprises a spline forming die (161) disposed next to the yoke forming die (151) to receive a material and said forming pin (161P) configured to be inserted into the tube part (3) and having said spline part (161P-a) formed on an outer circumferential surface thereof for forming the spline (SP) inside the tube part (3).
The tube yoke manufacturing apparatus of claim 4, configured
to respectively supply materials to be formed to the central groove forming mould (110), the first backward extrusion moulddie (120), the second backward forming mould (130), the preliminary yoke forming mould (140), the yoke forming mould (150), and the spline forming mould (160);

to simultaneously perform together the forming operations of the central groove forming mould (110), the first backward extrusion mould (120), the second backward forming mould (130), the preliminary yoke forming mould (140), the yoke forming mould (150), and the spline forming mould (160); and

a plurality of materials which are completely formed in respective moulds (110 - 160) are moved and supplied together at once to the moulds of the next processes.