KR101481200B1 - Manufacturing device and method thereof for crank throw - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing a crank throw and a method for manufacturing the crank throw, and more particularly, to an apparatus for manufacturing a crank throw of a "C" shape, which is a unit component constituting a crankshaft of a two- The present invention relates to a press unit for applying a vertical load, a plurality of toggle units mounted on the lower side of the press unit for converting a vertical load of the press unit into a horizontal load, A pair of upsetting molds connected to the left and right sides of the toggle portion, the toggle portion having a plurality of pairs of two toggle portions opposed to each other, the pair of upsetting molds being interposed between the pair of upsetting molds A bending die mounted on the press so as to apply a downward force to the preform, and a bending die installed on the bottom of the bending die to stop the metal flow Wherein the preform has a rounded shape and both ends of the preform are formed in a shape of a shaft journal of the crank throw. The crank throw forging apparatus according to claim 1, And between the engraved engraved portions formed opposite to each of the pair of the upsetting molds.

Description

TECHNICAL FIELD [0001] The present invention relates to a crank throw manufacturing apparatus and a crank throw manufacturing apparatus,

The present invention relates to an apparatus for manufacturing a crank throw and a method for manufacturing the crank throw, and more particularly, to an apparatus for manufacturing a crank throw of a "C" shape, which is a unit component constituting a crankshaft of a two- ≪ / RTI >

The main engines of large ships are mainly two-stroke diesel engines. Crankshaft, which is a core part of large-sized diesel engine, is manufactured by assembling the unit parts by heat shrinking method.

The unit parts of large crankshafts for ships are composed of a "C" shaped crank throw, a thrust shaft with two flanges, and a shaft flange with one flange. The crank throw is the largest component among the unit parts constituting the large crankshaft.

The existing crank throw manufacturing method is a free forging method, as shown in Fig. In the case of free forging, it is difficult to precisely control the dimension, and the amount of processing is large. Therefore, a lot of work is required in the subsequent gas cutting and machining processes.

Meanwhile, the crankshaft of a 4-stroke engine used as a secondary engine of a large ship or a small and medium-sized ship is manufactured by a continuous grain flow method. This method is called TR forging, designed by Taduesz Rut, and the devices and processes used in the continuous shear line method are introduced (European Patent No. 0003139).

The TR forging device is mounted on the press so that the vertical motion of the press is converted into a horizontal motion by the rotation of the toggle. At this time, the vertical load of the press is converted into a horizontal load, and a load greater than the vertical press load of the press can be applied to the material according to the angle of the toggle.

When the crankshaft is manufactured by the continuous sheathing method, the mold is composed of a vertical mold moving in the vertical direction and a horizontal mold moving in the horizontal direction.

 The vertical mold and the horizontal mold are simultaneously pressed in the vertical and horizontal directions with respect to the round rod shaped material, and as a result, a "C" shaped crank throw is produced. By repeating this process, a crankshaft having a continuous shear line is manufactured.

On the other hand, Tadeusrut, which devised TR forging, introduces a method of applying the TR forging method, which is a quasi-forging process, to a large crank throw manufacturing process (U.S. Patent No. 4041755).

As mentioned above, large crank throws made by free forging are difficult to control precisely and have a large amount of processing, which is costly for subsequent processing.

In order to solve such a problem, U.S. Patent No. 4041755 proposes a large crank throw forging method using a TR forging method. However, according to this method, it is necessary to first prepare a preform from an ingot, And an apparatus for molding a preform using the mold are separately required, resulting in low economic efficiency.

This forging device is composed of a wedge and a link (or a toggle), because the stroke of the crankshaft of the two-stroke diesel engine is relatively long compared with that of the crankshaft of four strokes, Since the forging device is difficult to implement proper kinematic characteristics, a forging device composed of a wedge and a link having a relatively long vertical distance is additionally constituted. However, this also requires additional cost in terms of having to build a separate device.

Therefore, the present invention aims at solving the problems of the method proposed in the prior art, and it is an object of the present invention to provide a technique which does not need to produce a preformed body resembling the final formed body and can utilize the general four-stroke crankshaft as it is .

In order to achieve the above object, the present invention provides a press apparatus comprising: a press unit for applying a vertical load; a plurality of toggles mounted below the press unit for converting a vertical load of the press unit into a horizontal load; And a pair of upsetting molds connected to the left and right sides of the toggle portion, the toggle portion having a pair of left and right opposed toggle portions, the pair of upsetting molds including a pair of upsetting molds, A bending mold mounted on the press so as to apply a pressing force to the preform held between the bending die and the bending die and an anvil provided on the bottom of the bending die to stop the metal flow, Wherein the preform has a rounded shape and both ends of the preform are shaped to fit the shape of a shaft journal of the crank throw. The crank throw forging apparatus according to claim 1, And between the pair of upsetting dies and the journal engraved portion formed opposite to each of the pair of upsetting dies.

Further, in the present invention, a virtual point on the upsetting mold on the horizontal load acting line of the toggle portion is in contact with the outline of the journal intaglio portion.

Further, in the present invention, the toggle portion may further include a washer for increasing a toggle angle at a connection point with the press unit, wherein widths of the crank throws on both sides of the upsetting mold, And a side mold for molding the side surface.

A manufacturing method of the present invention comprises a press unit for applying a vertical load, a plurality of toggle portions mounted below the press unit for converting a vertical load of the press unit into a horizontal load, A pair of upsetting molds mounted on respective ends of a pair of toggle portions which are disposed in an inward direction and which are opposed to each other, and a pair of upsetting molds, which are inserted into the pair of upsetting molds, A bending die mounted on a bending die and an anvil provided at a bottom of the bending die to stop the flow of metal, the method comprising the steps of: molding an ingot into a round bar preform; Forming a formed body by the crank throw manufacturing apparatus; forming an intermediate molded body by annealing and reheating the intermediate molded body; Wherein the anvil is replaced with an outer semicircular forming anvil of the crankpin and the bending mold is replaced with a bending die for inner semicircular molding of a crankpin, Attaching a washer for increasing a toggle angle to each of the pair of toggle portions to a connection point with the press unit to form a final formed body; Heat treatment, surface treatment and finishing to form a crank through.

Further, in the manufacturing method of the present invention, in order to form a rounded corner fillet around both ends in the longitudinal direction of the crank pin, a bending die for inner semicircular molding of the crank pin, Chamfering and rounding the corresponding portions of the anvil.

When the present invention is applied, it is possible to omit the expensive preform production step, and the manufacturing cost can be drastically reduced, thereby reducing the manufacturing cost and contributing to the cost competitiveness.

FIG. 1 is a schematic flow chart illustrating a manufacturing process of a conventional crank throw.
Fig. 2 is a schematic front view explaining the primary machining in an embodiment to which the present invention is preferably applied, in which (a) shows before machining, and Fig. 2 (b) shows after machining.
Fig. 3 is a schematic front view explaining secondary machining in an embodiment to which the present invention is preferably applied, in which (a) shows before machining, and Fig. 3 (b) shows after machining.
Fig. 4 is a three-dimensional front view explaining primary processing in an embodiment to which the present invention is preferably applied. Fig. 4 (a) shows a state before machining, and Fig. 4 (b) shows a state after machining.
Fig. 5 is a three-dimensional front view illustrating a secondary machining in an embodiment to which the present invention is preferably applied, in which (a) shows before machining, and Fig. 5 (b) shows after machining.
6 is an upsetting mold according to an embodiment of the present invention, wherein (a) is a perspective view, (b) is a front view, and FIG. 6 (c) is a side sectional view.
Fig. 7 is a perspective view of a bending die for primary machining, in which (a) is a front view of (a), and Fig. 7 (c) is a side cross- (D) is a perspective view of a bending die for secondary machining, (e) is a front view of (d), and (f) is a side sectional view of (d).
FIG. 8 is an anvil for primary processing in an embodiment of the present invention, wherein (a) is a perspective view, (b) is a front view, and FIG. 8 (c) is a side sectional view.
Fig. 9 is a perspective view of a second anvil and side mold for an embodiment of the present invention, wherein (a) is a perspective view, (b) is a front view, and Fig. 9 (c) is a side sectional view.
FIG. 10 is a perspective view showing the end of the secondary machining, FIG. 10 (b) is a perspective view showing the final molded product, and FIG. 10 (c) Is a front view showing the final molded product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present embodiment, in manufacturing a crank throw of a two-stroke large-sized diesel engine by the TR forging method, it is not necessary to preliminarily manufacture an intermediate formed body resembling a finished product as a preform, Shaped preform 5 cut into a single round bar shape can be directly introduced into the present forging process. In this embodiment, by the structure of the mold and the optimal arrangement of these molds, By suitably controlling the direction of action of the reaction force in the reaction chamber 5.

Fig. 2 is a schematic front view explaining primary processing in an embodiment to which the present invention is preferably applied, in which (a) shows the state before the processing, (b) shows the state after the processing, and Fig. 3 shows the state where the present invention is preferably applied Fig. 4 (a) is a schematic front view explaining the secondary machining in one embodiment, Fig. 4 (a) is a view showing the first machining in the embodiment in which the present invention is preferably applied Fig. 5 is a three-dimensional frontal view for explaining secondary processing in an embodiment to which the present invention is preferably applied, in which (a) (B) represents the post-processing.

The construction of the manufacturing apparatus 1 of the present embodiment mainly comprises a mold for pressing the preform 5 by the press unit 2, the toggles 3 and 4 and the toggles 3 and 4, Particularly, the toggle portions 3 and 4 are widely used as an efficient mechanism having a large increase in the force due to a general mechanical relationship. The toggle portions 3 and 4 are mounted on the lower side of the press unit 2, To an amplified horizontal load.

In the present embodiment, in order to effectively amplify the horizontal load by the toggle portion, an imaginary vertical center line is drawn near the vertical load center of the press unit 2, and the left and right The pair of toggles 3 and 4 is tilted at a toggle angle a within a range in which the relationship of the horizontal travel distance and the additional load is mechanically satisfied, Are arranged to face the imaginary vertical center line. On the other hand, in the secondary machining to be described later, the toggle angle a is set within a range that satisfies the relationship of the horizontal movement distance < addition load.

In this embodiment, the toggle portions 3 and 4 are formed by two pairs of left and right sides. However, the present invention is not limited to this, and a pair of right and left facing pairs of the toggle portions 3 and 4 may be formed into a plurality of sets, 4) so that the back surface of the mold is supported at a plurality of places, and this is also included in the scope of the present invention.

A pair of upsetting molds 10 and 11 are mounted opposite each other at the ends of the pair of toggle portions 3 and 4 arranged opposite to each other.

6 is an upsetting mold according to an embodiment of the present invention, wherein (a) is a perspective view, (b) is a front view, and FIG. 6 (c) is a side sectional view.

In the present embodiment, the upsetting molds 10 and 11 are formed in a circular shape, and the diameter of the crank journal 51 protruding from both sides of the outer side of the crank throw, And a groove engraved portion 103 having a diameter corresponding to the diameter of the crank pin 53 is formed in the lower portion of the center line, 104 are formed.

Here, the upsetting molds 10 and 11 of the present embodiment are separated into a mantle 101 and a mantle 102, which share a diameter of the same shaft journal 51 on one crankshaft, By replacing Hartley only in response to throw, the cost of manufacturing the mold can be reduced.

As described above, in the present embodiment, the center of the journal engraved portion 103 is offset upward from the center of the upsetting die which coincides with the center of the horizontal load. In this state, when the rod-shaped preform 5 is sandwiched between the confronting journal intaglio 103 and the forging process starts and a horizontal load is applied, the horizontal load applied to the preform 5 The reaction force is directed from the left and right to the upper side at the same time, and when the horizontal load is continuously applied, the preform 5 is deformed into an upwardly curved arc shape.

Therefore, if the left and right reaction forces in the preform 5 are directed downward, a half stroke of a two-stroke crank throw that is longer than the four-stroke crank throw is finally obtained. In this embodiment, in order to direct the reaction force downward, bending dies 20 and 21 for applying a downward force to the central portion of the preform 5 in cooperation with the press unit 2 Respectively.

The bending dies 20 and 21 are elongated flat plate members having connection portions 201 and 211 connected to the press unit 2 at the upper portion thereof and recess portions 202 for forming crank pins are formed at the bottom portions thereof As described later, in the crank throw manufacturing process which is carried out by dividing into the primary machining and the secondary machining, the bending die 20 for primary machining and the bending die 21 for secondary machining, And the widths of the molding concave portions 202 are different from each other.

Here, the distance between the center of the journal 51 of the large crank throw and the center of the crank pin 53 is half the stroke distance of the engine, and the vertical pressing distance of the bending mold at the time of TR forging should be equal to half-stroke .

In the case of the bending die 20 for primary machining, the length corresponds to about two-thirds of the half stroke of the crank throw, and the width d1 of the crank pin forming recess is smaller than the width d1 of the crank pin Is 1.2 to 1.5 times as large as the diameter

On the other hand, an anvil 30 is provided at the bottom of the bending mold 20. The anvil 30 is provided at the bottom of the bending mold 20 to stop the downward flow of the metal continuously downward by the downward reaction force. 5 ') is 60 to 80% of the final formed body 5' '.

Thus, after the horizontal load of the toggle portions 3 and 4 is applied to the preform 5 in the first machining, the reaction force generated in the preform 5 with respect to the horizontal load is directed downward by the bending metal 20 It is reflected by the anvil 30 and directed to the preform 5 in the vicinity of the horizontal load center line of the upsetting molds 10 and 11. [ The preform 5 is gradually deformed into the desired intermediate formed body 5 'along the action path of such a reaction force.

In the secondary processing, as described above, the toggle angle a is set within a range satisfying the relationship of the horizontal movement distance < additional load, and a load higher than the movement distance must be applied to the intermediate formed body 5 ' To this end, in the present embodiment, a washer 6 for increasing the toggle angle a is fitted to the toggle portions 3 and 4 at the connection point with the press unit 2.

On the other hand, in the secondary machining, the bending mold and the anvil are also replaced. The bending die 21 for secondary machining has the length corresponding to the half stroke and the width d2 of the recess for crank pin forming as described above. The anvil is replaced with an anvil 31 having a semicircular concave portion 311 corresponding to the shape of the outer periphery of the crank pin 53 in the final formed body 5 ".

In the secondary machining, four side molds 41 and 42 for forming side surfaces in the width direction of the crank throws are added to both sides of the upsetting molds 10 and 11 in the width direction, And the side molds of the final formed body 5 "are also determined by the side molds 41 and 42. The side molds 41 and 42 are provided with different crankshafts of different half strokes It is of course also possible to have different lengths and sides corresponding to the rows.

The manufacturing method of the crank throw will be described in a time-wise manner as follows.

First, an ingot having a round cross section is cut to form a round bar-shaped preform 5, and then the preform 5 is cut by the crushing throw manufacturing apparatus 1 into an intermediate formed body 5 ' ).

The intermediate formed body 5 'is subjected to an annealing and reheating step to remove work hardening due to agglomeration between particles before being put into the secondary forging operation.

The bending mold 20 is used as the bending die 21 for forming the inner semicircle of the crank pin and the anvil 30 is fixed to the crank pin The outer semicircular forming anvil 31 of FIG.

Side molds 41 and 42 for forming side surfaces in the width direction of the crank throw are mounted on both sides in the width direction of the upsetting molds 10 and 11 and the pair of toggles 3 and 4 The washer 6 for increasing the toggle angle a is attached to the connection point with the press unit 2 to complete the preparation of the secondary machining.

During the secondary machining, the moving distance of the toggle portions 3 and 4 is reduced compared with that in the primary machining, but the increase ratio of the force is increased by the increased toggle angle a. Therefore, the thickness thereof is reduced as it approaches the predetermined final formed body 5 ", so that the reaction force inside the formed body acts in the width direction and the longitudinal direction, and the width and length thereof increase greatly as compared with the intermediate formed body 5 '.

After the secondary machining is finished and a predetermined final formed body 5 "is obtained, the heat treatment is performed to alleviate the stress accumulated in the internal structure and the brittleness of the work. Subsequently, surface processing is performed to obtain a predetermined surface roughness, Complete the crank throw.

On the other hand, when the circumferential edges of the crank pin 53 in the longitudinal direction, that is, the connecting point with the crank arm 52, are angular corners, the stress concentration degree at the time of repeated use becomes relatively higher than that at other portions and cracks may occur.

Therefore, it is preferable that the corner is formed by a fillet having a rounded cross-sectional shape. For this purpose, the crank pin forming concave portion 202 (or 202) of each of the bending dies 20 and 21 for the first- And 212 may be subjected to chamfering and rounding along both sides thereof.

The method proposed by the present invention is intended to secure economical efficiency in producing a preform by presenting a simple round bar shape as a preform, and by using a manufacturing apparatus for forging a four-stroke crankshaft by dividing the manufacturing process by forging into two stages, Making it possible to produce long two stroke crank throws.

Fig. 10 shows that the flash protruding around the final molded article as a result of the three-dimensional analysis can be easily removed by gas cutting.

1: Manufacturing apparatus
2: Press unit
3, 4: toggle portion
5: preform
5 ': intermediate mold
5 &quot;: final formed body
6: Washer
10, 11: Upsetting mold
101: Suttle
102: Hartle
103: Journal intaglio part
104: Concave slope
20, 21: Bending mold
201, 211: Connection
202 and 212: recesses for crank pin formation
30, 31: Anvil
311: Semicircular concave portion
41, 42: side mold
51: Crank Journal
52: crank arm
53: Crank pin

Claims (5)

A plurality of toggle portions mounted on the lower side of the press unit for converting a vertical load of the press unit into a horizontal load, A pair of upsetting molds connected to the left and right sides of the toggle portion in which a pair of two sets of the toggle portions are arranged in a plurality of sets and a pair of upsetting molds connected to the pair of upsetting molds, A crank throw forging device comprising a bending mold mounted on the press to apply a pressing force to the bending mold and an anvil installed on a bottom of the bending mold to stop the flow of metal,
Wherein the preform has a round shape,
Wherein both ends of the preform are located between journal intaglio parts formed opposite to the pair of upsetting dies in conformity with the shape of a shaft journal of the crank throw. The method according to claim 1,
Wherein the center of the journal engraved portion is offset upward from the center of the upsetting die that matches the center of the horizontal load. 3. The method of claim 2,
Wherein the toggle portion further comprises a washer capable of adjusting the thickness of the final formed body by increasing a toggle angle at a point of connection with the press unit,
Further comprising side molds on both sides of the upsetting mold in the width direction for forming side surfaces in the width direction of the crank throw. A plurality of toggles which are mounted below the press unit and convert the vertical load of the press unit into a horizontal load; A pair of upsetting molds mounted on respective front ends of the pair of toggle portions; a bending mold mounted on the press so as to apply a pressing force to the preforming body sandwiched between the pair of upsetting molds during forging; And an anvil provided at a bottom of the bending mold to stop the flow of metal, the method comprising:
Molding the ingot into a round bar-shaped preform,
Forming the preform by an intermediate mold by the crank throw manufacturing apparatus,
Annealing and reheating the intermediate formed body;
Wherein the bending mold is replaced with a bending die for inner semicircular molding of a crank pin, the anvil is replaced with an outer semicircular forming anvil of the crankpin, A step of mounting a side mold for molding a side surface and a toggle angle for each of the pair of toggle portions to form a final molded body by mounting a washer for adjusting a thickness of the final formed body to a connection point with the press unit;
And shaping the final formed body into a crank through by heat treatment, surface finishing and finishing. 5. The method of claim 4,
A bending die for inner semicircular molding of the crankpin and a corresponding portion of an outer semicircle forming anvil of the crankpin are chamfered and rounded to form a rounded corner fillet around both longitudinal ends of the crankpin Wherein the crankshaft is a crankshaft.

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