Railway freight car knuckle forging method and special die thereof

Abstract

The present application provides a railway freight car knuckle forging method, 1) blank heating, mold preheating; 2) opening mold, placing the blank horizontally into the lower mold body, the lower mold body mold groove shape corresponds to the inside S surface side of the knuckle forging; 3) the horizontal punch slightly upsets the blank from both sides to position the blank in the middle of the mold groove; the inside shape of the horizontal punch corresponds to the shape of the left and right side surfaces of the knuckle forging; 4) closing mold, the upper mold body mold groove surface shape corresponds to the outer S surface shape of the knuckle forging; 5) two horizontal punches extrude the blank from both sides of the knuckle forging, push into the mold cavity from both sides of the mold groove, so that the blank fills the mold cavity; 6) opening mold, the knuckle forging is ejected from the lower mold body; the special mold for the railway freight car knuckle forging method: the upper mold body, the lower mold body and the left and right two horizontal punches form a mold cavity; the upper mold groove corresponds to the outer S surface of the knuckle forging; the upper mold groove is also fixedly connected with an inclined block corresponding to the weight reduction groove; the lower mold groove corresponds to the inside S surface of the knuckle, and the horizontal punch extends into the mold cavity from both sides.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of part processing, and specifically relates to a railway wagon knuckle forging method and a special die thereof. BACKGROUND

[0002] The knuckle is a key connecting component between a railway freight locomotive and a vehicle or between vehicles. Because of its complex shape, it is currently manufactured by casting. The knuckle is subjected to traction, compression and impact forces during operation, and wear and cracks often occur, affecting the safe operation of trains. With the development of trains towards high speed and heavy load, the knuckle bears increasingly large alternating loads, and the failure rate is increasingly high, and the service life is increasingly short. The mechanical properties of the cast knuckle are low, and the casting process may have defects such as segregation, pores, inclusions and cracks.

[0003] The mechanical properties of the knuckle manufactured by the forging process can be greatly improved, so in recent years the inventors have conducted a lot of research in the direction of processing technology for manufacturing the knuckle by the forging process. The applicant of the present application has applied for a Chinese invention patent with application number 202211050254.5, publication number CN115383029A and publication date 2022.11.25, which discloses a multi-directional die forging die for a railway locomotive knuckle forging and a forming process thereof. The forging die forming process is: after the blank is heated, it is placed in the lower die cavity, and then the die is closed and stamped. Since the blank is a round bar, it cannot be stabilized in the cavity when it is initially inserted into the cavity. At this time, the blank is directly closed and pressed, and in addition to deformation, it is also easy to shift in the cavity, even to jump, and the deformation effect is not good. In fact, since the knuckle formation is relatively complex, the blank generally adopts a standard round or square shape, and is not stable during the initial deformation in the irregular curve cavity.

[0004] The above-mentioned application also discloses a forging die, which comprises an upper die assembly and a lower die assembly, the upper die assembly comprises an upper die, an upper punch and a side punch, the upper die is the main body of the upper die assembly; the upper punch is arranged in the hole cavity on the bottom surface of the upper die, and the lower end of the upper punch is an arc-shaped protrusion corresponding to the traction curved surface groove of the knuckle; the side punch is arranged in the groove structure in the middle of the bottom of the upper die. The die designed in this scheme actually comprises six blocks, the blocks are relatively many, and each block needs to be respectively configured with a pressure control machine, which is inconvenient to operate and the forging equipment is high in cost. At the same time, burrs and indentations are easily formed on the surface of the forging after the die joint position is stamped, the die blocks are many, the joint of part of the blocks and the blocks is on the surface of the knuckle, the surface is not flat after being stamped, and a large amount of polishing and repair needs to be performed. SUMMARY

[0005] To solve the problems in the prior art, the present application provides a forging process for avoiding the jumping of a blank in a multi-curved surface forging cavity.

[0006] The present application solves the problem, and the technical scheme adopted is:

[0007] A railway freight car knuckle forging method, the knuckle forging piece front end is a hook head, the rear end is a traction platform, the hook head and the traction platform hook head outside are collectively referred to as the outer S surface, and the inside is collectively referred to as the inner S surface; The left and right sides of the hook head are provided with a pin protection flange and an impact platform; The outer S surface of the hook head is provided with a weight reduction groove, and the specific operation of forging the knuckle forging piece is as follows:

[0008] S1: The blank is a round bar with a diameter of 160mm, heated to the initial forging temperature and kept; The mold is preheated to 200-300℃;

[0009] S2: Open the mold, place the blank horizontally in the lower mold body, and the lower mold body mold groove shape corresponds to the inner S surface side of the knuckle forging piece;

[0010] S3: The lower mold body is provided with horizontal punches corresponding to the hook head position on both sides, and the left and right horizontal punches move oppositely to slightly upset the blank, and push the blank to the middle position of the lower mold body mold groove;

[0011] S4: The upper mold body is lowered in a pressure control mode to close with the lower mold body, and the upper mold body mold groove shape corresponds to the outer S surface shape of the knuckle forging piece;

[0012] S5: The two horizontal punches are pushed into the mold cavity from both sides in a pressure control mode, oppositely extruding the blank, so that the blank metal fills the mold cavity, forming a knuckle forging piece;

[0013] S6: The upper mold body goes up and back, the horizontal punch goes back, and the knuckle forging piece is ejected from the lower mold body mold groove.

[0014] Compared with the prior art, the forging method has the following outstanding features:

[0015] The method fixes the blank when stamping the upper and lower molds, reduces the turning or jumping (shifting) of the blank in the mold cavity due to the impact of the complex protruding structure, and protects the stable deformation of the blank.

[0016] In order to solve the problems of complex mold structure, inconvenient use and poor forming, the present application also provides a mold for forging knuckle forging pieces.

[0017] The present application solves the problem, and the technical scheme adopted is:

[0018] The application discloses a special forging die for a railway freight car knuckle forging, which comprises an upper die body and a lower die body, the upper die body is provided with an upper die groove, and the shape of the upper die groove corresponds to the outer S surface of the knuckle forging; the lower die body is provided with a lower die groove; the upper die groove is further fixedly connected with an inclined block corresponding to a weight-reducing groove, the inclined block is inserted into the lower die groove along the die wall of the lower die groove; the upper die groove and the lower die groove are provided with left and right through openings corresponding to the position of the knuckle head; the left and right through openings are provided with horizontal punches, and the inner side of the horizontal punch corresponds to the guard pin flange and the impact platform of the knuckle forging; the upper die body, the lower die body and the left and right horizontal punches form a die cavity.

[0019] Compared with the prior art, the application has the following prominent features:

[0020] 1) The die is composed of only four blocks, and only needs to be provided with an upper die pressure mechanism and a horizontal punch pressure mechanism, so that the die has less blocks, and is convenient for manufacturing and controlling; 2) The junctions and joints of the blocks are arranged along the forging contour line, so that burrs or indentations are not generated, and the forming effect is good.

[0021] As a preferred, the further technical scheme of the application is:

[0022] The lower part of the horizontal punch further comprises a boss, the bosses of the left and right horizontal punches are connected to each other, and the boss extends into the knuckle head and corresponds to the hook curve of the inner S surface of the knuckle head. According to the scheme, the horizontal punch can extend into the die cavity and connect to the left and right sides, and the upper die body and the lower die body are combined more stably; and the horizontal punch is a small block relative to the upper die body and the lower die body, so that the shape of the inner S surface of the knuckle head can be changed by replacing the small block, and the deformation cost is low.

[0023] Two through holes are arranged in the lower die body and correspond to the knuckle head and the traction platform respectively; a top block is arranged in each through hole and protrudes downward from the lower side of the lower die body; the lower die body is arranged on a concave-shaped lower die base plate, a lower ejector plate is arranged in the lower die base plate, and the top block falls on the lower ejector plate; a through hole is arranged in the bottom plate of the lower die base plate, and a lower ejector plate ejector rod is arranged in the through hole. According to the scheme, the forging can be smoothly ejected. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is the structure of the knuckle forging of the application Figure 1 ;

[0025] Figure 2 It is the structure of the knuckle forging of the application Figure 2 ;

[0026] Figure 3 It is the main view of the open die state of the forming die of the application

[0027] Figure 4 It is the sectional view of the open die state of the forming die of the application

[0028] Figure 5 It is the schematic view of the horizontal punch of the die of the application

[0029] Figure 6 is the schematic diagram of the upper die structure of the present application;

[0030] Figure 7 is the schematic diagram of the lower die structure of the present application.

[0031] In the figure: 1, hook tongue forging; 101, hook head; 102, traction platform; 103, pin guard flange; 104, impact platform; 105, outer S surface; 106, weight reduction groove; 107, inner S surface; 2, upper die body; 201, upper die groove; 202, inclined block; 3, lower die body; 301, lower die groove; 4, blank; 5, top block; 6, lower top plate; 7, lower die backing plate; 8, lower top plate push rod; 9, horizontal punch; 901, boss; 10, through hole; 11, opening. DETAILED DESCRIPTION

[0032] The present application is further described below in conjunction with examples, the purpose of which is only to better understand the content of the present application, therefore, the examples do not limit the protection scope of the present application.

[0033] The present application takes a certain type of hook tongue forging 1 as an example to illustrate the process of the present application. The shape of the hook tongue forging 1 made in this embodiment is shown in Figure 1 , Figure 2 The front end of the hook tongue forging 1 is a hook head 101, the rear end is a traction platform 102, the back side of the hook tongue is its outer S surface 105, and the ventral side of the hook tongue is its inner S surface 107; the hook head 101 is provided with a pin guard flange 103 and an impact platform 104 on the left and right sides; the hook head 101 is provided with a weight reduction groove 106, and the method of forging and forming of the hook tongue forging 1 and the forming die are described.

[0034] The method of forging and forming of the above-mentioned hook tongue forging 1 of the present application is described in detail as follows:

[0035] S1: The blank 4 is a round bar with a diameter of 160 mm, heated to the initial forging temperature and kept for a certain time; the die is preheated to 200-300°C. The initial forging temperature is generally 1200°C±20°C.

[0036] S2: Open the mold, place the blank 4 horizontally into the lower die body 3, and the shape of the lower die body 3 groove corresponds to the ventral side of the hook tongue forging 1.

[0037] S3: Two horizontal punches 9 are arranged on both sides of the lower die body 3 corresponding to the position of the hook head 101, the two horizontal punches 9 move towards each other to slightly upset the blank 4, and the blank 4 is pushed to the middle position of the lower die body 3 groove.

[0038] S4: The upper die body 2 is lowered in a pressure control mode to close the mold with the lower die body 3, and the shape of the upper die body 2 groove corresponds to the shape of the outer S surface 105 of the hook tongue forging 1.

[0039] S5: two horizontal punches 9 are pushed into the mold cavity from both sides in a pressure control mode, and the blank 4 is extruded to make the blank 4 metal fill the mold cavity, and the inner side shape of the horizontal punch 9 corresponds to the guard pin flange 103 and the impact platform 104 of the hook head 101 of the knuckle forging 1, and the knuckle forging 1 is formed.

[0040] S6: the upper die body 2 goes up and returns, the horizontal punch 9 retreats, and the knuckle forging 1 is ejected from the lower die body 3.

[0041] Based on the above forging method, the present application also designs a special mold for the above forging, see Figures 3 to 7 A special mold for forging a knuckle forging 1 of a railway freight car, comprising an upper die body 2 and a lower die body 3, characterized in that: the upper die body 2 is provided with an upper die groove 201, and the shape of the upper die groove 201 corresponds to the outer S surface 105 of the knuckle forging 1; the lower die body 3 is provided with a lower die groove 301; the upper die groove 201 is further fixedly connected with an inclined block 202 corresponding to the weight-reducing groove 106, and the inclined block 202 is inserted into the lower die groove 301 along the die wall of the lower die groove 301; the positions of the upper die groove 201 and the lower die groove 301 corresponding to the hook head 101 are left-right through openings 11; the horizontal punch 9 is arranged on both sides of the opening 11, and the inner side shape of the horizontal punch 9 corresponds to the guard pin flange 103 and the impact platform 104 of the knuckle forging 1; the upper die body 2, the lower die body 3 and the two horizontal punches 9 on the left and right sides form a mold cavity.

[0042] Preferably, the shape of the lower die groove 301 of the mold is not the same as the shape of the inner S curved surface of the knuckle, but the curved surface corresponding to the hook is enlarged, and the curved surface is larger than the diameter of the round bar-shaped blank 4, and the round bar-shaped blank 4 can be placed at the bottom of the lower die groove 301. The inner curved surface of the hook of the knuckle can be formed by the horizontal punch 9, specifically: the lower part of the horizontal punch 9 further comprises a boss 901, and the bosses 901 of the horizontal punches 9 on both sides are connected, and the boss 901 extends into the hook head 101 and corresponds to the hook curve of the inner S surface 107 of the hook head 101.

[0043] The lower die body 3 is provided with two through holes 10, and the two through holes 10 correspond to the hook head 101 and the traction platform 102 respectively; the through holes 10 are respectively provided with ejector pins 5, and the lower ends of the ejector pins 5 protrude from the lower side of the lower die body 3; the lower die body 3 is installed on a concave-shaped lower die pad 7, and the lower die pad 7 is provided with a lower ejector plate 6, and the ejector pins 5 fall on the lower ejector plate 6; the bottom plate of the lower die pad 7 is provided with a through hole, and a lower ejector plate push rod is arranged in the through hole. The lower ejector plate 6 is supported by the lower ejector plate push rod 8 extending into the through hole, the lower ejector plate 6 pushes the ejector pins 5, and the ejector pins 5 push the knuckle forging 1 out of the mold.

[0044] The present application adopts a composite die structure, the upper die body 2 cavity contains two inclined blocks 202 besides the horizontal die surface, to form two weight-reducing grooves 106 of the hook tongue forging 1. The lower die body 3 cavity is not designed in the same shape as the forging, but is punched through to realize the placement of the round bar blank 4. The horizontal punch 9 only forms the end face of the forging, but in order to use the round bar blank 4, the horizontal punch 9 is increased by a boss 901, which cooperates with the lower die body 3 to form a lower die cavity corresponding to the S surface 107 of the hook tongue forging 1.

[0045] Die installation: according to the die structure of the present application, the die is assembled, wherein the lower die body 3 is connected with the lower die pad 7; the lower die pad 7 is connected with the workbench of the multi-directional die forging press; the two top blocks 5 are installed in the through hole 10 of the lower die body 3, without the need of being connected with other structures; the lower top plate 6 is arranged in the lower die pad 7, without the need of being connected with other components; the lower end of the lower top plate push rod 8 is connected with the ejection cylinder, and the upper end can penetrate the through hole of the lower die pad 7 to contact the lower top plate 6, without the need of being connected with the lower top plate 6; the upper die body 2 is connected with the moving beam of the multi-directional die forging press; and the horizontal punch 9 is connected with the horizontal cylinder of the multi-directional die forging press. After the die is assembled on the die table according to the above requirements, the forging can be prepared. The beneficial effects of the present application are as follows:

[0046] The method of the present application fixes the blank during the upper and lower die stamping, reduces the displacement or jumping (shifting) of the blank in the die cavity caused by the impact of the complex protruding structure, and protects the stable deformation of the blank.

[0047] The die of the present application only includes four blocks, and only needs to set the upper die pressure mechanism and the horizontal punch pressure mechanism, so the structure is simple and the use is convenient.

[0048] The junction and joint of each block of the die of the present application are arranged along the forging contour line, without burrs or indentations, and the forming effect is good.

[0049] The forging forming method provided by the present application only needs to heat the round bar blank once, and the multi-directional die forging press works once, so that the hook tongue forging with small machining allowance can be obtained, the process is less, the process is simple, the material utilization rate and production efficiency are high, and the cost is low.

[0050] The above only describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application, and any equivalent changes made by referring to the content of the present application and the drawings are included in the scope of the present application.

Claims

1. A method for forging a railway freight car hook tongue, wherein the hook tongue forging (1) has a hook head (101) at the front end and a traction platform (102) at the rear end, the back side of the hook head (101) and the traction platform (102) are collectively referred to as the outer S-surface (105), and the belly side is collectively referred to as the inner S-surface (107); the left and right sides of the hook head (101) are provided with a protective pin flange (103) and an impact platform (104); the outer S-surface (105) of the hook head (101) is provided with a weight reduction groove (106), characterized in that: The mold for the hook tongue forging (1) includes an upper mold body (2) and a lower mold body (3). The upper mold body (2) is provided with an upper mold groove (201), the shape of which corresponds to the outer S-surface (105) of the hook tongue forging. The lower mold body (3) is provided with a lower mold groove (301). The upper mold groove (201) is also fixedly connected with an inclined block (202) corresponding to the weight reduction groove. The inclined block (202) is inserted into the lower mold groove (301) along the mold wall of the lower mold groove (301). The upper mold groove (201) and the lower mold groove (301) are connected to the hook head (101) with a left-right through opening (11). Horizontal punches (9) are provided on both sides of the opening (11). The inner shape of the horizontal punches (9) corresponds to the hook tongue. The forging has a protective pin flange (103) and an impact table (104); the upper die body (2), the lower die body (3) and two horizontal punches (9) on the left and right sides form a mold cavity; the lower die body (3) has two through holes (10), which correspond to the hook head (101) and the traction table (102) respectively; top blocks (5) are installed in the through holes (10), and the lower end of the top blocks (5) protrudes from the lower side of the lower die body (3); the lower die body (3) is installed on the U-shaped lower die pad (7), and the lower die pad (7) has a lower top plate (6), and the top blocks (5) fall on the lower top plate (6); the bottom plate of the lower die pad (7) has a through hole, and the lower top plate push rod (8) is installed in the through hole. The specific operation for forging the hook tongue forging (1) is as follows: S1: The billet (4) is a round bar with a diameter of 160mm, heated to the initial forging temperature and held at that temperature; the mold is preheated to 200℃-300℃; S2: Open the mold and place the blank (4) horizontally into the lower mold body (3). The shape of the mold groove of the lower mold body (3) corresponds to the shape of the inner S surface (107) of the hook tongue forging (1). S3: Horizontal punches (9) are set on both sides of the lower mold body (3) corresponding to the position of the hook head (101). The two horizontal punches (9) move in opposite directions to perform a small upsetting on the blank (4) and push the blank (4) to be positioned in the middle of the mold groove of the lower mold body (3). S4: The upper mold body (2) descends under pressure control to close with the lower mold body (3). The shape of the mold groove of the upper mold body (2) corresponds to the shape of the outer S surface (105) of the hook tongue forging (1). S5: Two horizontal punches (9) are pushed into the mold cavity from both sides by pressure control, and the blank (4) is squeezed in opposite directions, so that the blank (4) metal fills the mold cavity to form a hook tongue forging (1). S6: The upper die body (2) moves upward and returns, the horizontal punch (9) moves horizontally and returns, and the hook tongue forging (1) is ejected from the mold groove of the lower die body (3).

2. The method for forging railway freight car couplers according to claim 1, characterized in that: The lower part of the horizontal punch (9) also includes a boss (901). The bosses (901) of the two horizontal punches (9) are connected to each other. The boss (901) extends into the hook (101) and corresponds to the hook curve of the inner S surface (107) of the hook (101).

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