Straight toothed inert gear forging forming die

Abstract

The utility model introduces a kind of spur gear inert gear forging forming die, including upper die assembly, extruding die core subassembly, fine forging die core subassembly and lower die assembly;Extruding die core subassembly and fine forging die core subassembly are alternately arranged between upper die assembly and lower die assembly.The die structure of the utility model can ensure that the part is cold extruded near net shape, shorten the processing cycle, improve production efficiency, improve material utilization, reduce production cost, improve the hardness and tensile strength of the part to improve the mechanical properties of the part itself, solve the problem of once closed die forging spur gear inert gear corner filling after forging, low die life.

Description

Technical Field

[0001] This utility model relates to the field of forging mold technology, and in particular to a forging mold for spur gears. Background Technology

[0002] A spur idler gear is a gear that acts as a transmission gear between two non-contacting transmission gears. It meshes with both gears to change the rotation direction of the driven gear so that it is the same as the driving gear. Its function is only to change the direction of rotation and cannot change the transmission ratio. It is called an idler gear.

[0003] In existing technologies, the processing of spur gears generally employs bar machining or one-time closed-die forging. Because gears have a large number of teeth, machining requires the removal of a significant amount of excess material, resulting in a long processing cycle. Furthermore, the mechanical properties of the product obtained through direct bar machining to remove excess material depend on the mechanical properties of the bar itself; therefore, the metal flow lines are interrupted during machining, leading to poor product mechanical properties. Additionally, overall machining requires a large volume of material, resulting in high material requirements per piece and low processing efficiency. The efficiency and performance of products produced using this method cannot meet market demands for these parts. One-time closed-die forging, on the other hand, suffers from unavoidable sudden increases in forming force at the end of the forming process, incomplete corner filling, leading to a very short die life and a high scrap rate due to incomplete corner filling. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a forging die for spur gears that can utilize near-net-shape forming of materials, combined with a small amount of supplementary machining, to improve product precision, ensure product performance, and increase production efficiency.

[0005] The technical solution adopted in this utility model is: A forging die for spur gears includes an upper die assembly, an extrusion die core assembly, a precision forging die core assembly, and a lower die assembly; the extrusion die core assembly and the precision forging die core assembly are alternately arranged between the upper die assembly and the lower die assembly; The extrusion die core assembly includes an upper die core A, a concave die A, and a lower die core A. The upper die core A is located at the center of the upper die assembly, and the lower die core A is concentrically located within the center of the concave die A. Both the upper die core A and the lower die core A are gear column structures, and the lower end face of the upper die core A and the upper end face of the lower die core A both have the same frustum structure protruding from them. The concave die A is located at the center of the lower die assembly. The concave die A is a cylindrical structure with a tapered outer edge. The inner wall of the concave die A has tooth grooves that match the teeth on the lower outer edge of the upper die core A and the teeth on the outer edge of the lower die core A. The tooth thickness and root circle of the tooth grooves in the concave die A are both smaller than the size of the finished gear. The precision forging die core assembly includes an upper die core B, a die cavity B, and a lower die core B. The upper die core B is located at the center of the upper die assembly, and the lower die core B is concentrically located within the center of the die cavity B. The upper die core B is a hollow gear column structure, and the lower die core B is also a gear column structure. Both the lower end of the upper die core B and the center of the upper end of the lower die core B are provided with overflow holes. The lower end face of the upper die core B and the upper end face of the lower die core B are uniformly provided with protrusions around the overflow holes, which match the shape of the oil grooves on both ends of the finished gear. The die cavity B is located at the center of the lower die assembly. The die cavity B is a cylindrical structure with a tapered outer edge. The inner wall of the die cavity B is provided with tooth grooves that match the teeth on the lower outer edge of the upper die core B and the teeth on the outer edge of the lower die core B. The tooth thickness and root circle of the tooth grooves of the die cavity B are consistent with the dimensions of the finished gear.

[0006] Specifically, the upper mold assembly includes an upper mold sleeve, an upper mold flange, an upper mold pad, and an upper mold locking nut; the upper mold sleeve is a cylindrical structure with an installation step on the upper outer edge, and upper mold core A or upper mold core B is alternately arranged in the center of the upper mold sleeve; the upper mold flange is connected to the upper template of the press through a pressure plate, and the lower outer edge of the upper mold flange is provided with external threads; the upper mold pad is arranged inside the upper mold flange, the upper end of the upper mold sleeve is arranged inside the upper mold flange below the upper mold pad, and the upper mold locking nut is arranged on the installation step of the upper mold sleeve and is threadedly connected to the upper mold flange.

[0007] Specifically, the lower mold assembly includes a mold cylinder, a push rod nest, a push rod, a lower mold pad, a mold base, a center ring, a lower mold core pad, a lower mold outer ring, a lower mold middle ring, and a pressure ring. The mold cylinder is connected to the lower mold platen of the press via bolts and a pad. A mounting hole is provided at the center of the bottom of the mold cylinder. The push rod nest is interference-fitted into the mounting hole, and the push rod passes through the push rod nest. The lower mold pad is located at the bottom of the mold cylinder, and a through hole corresponding to the inner hole of the push rod nest is provided in the middle of the lower mold pad. The mold base is located at the center of the lower mold pad via a center ring, and the inner hole of the mold base has a variable diameter structure. The lower mold core pad is located at the bottom of the mold base, and lower mold core A or lower mold core B is alternately located on the lower mold core pad in the mold base. Lower mold core A or lower mold core B protrudes from the upper end of the mold base. Die A or die B is alternately located in the lower mold middle ring, the lower mold outer ring is located outside the lower mold middle ring, and the pressure ring is located outside the lower mold outer ring. The pressure ring is connected to the upper end ring surface of the mold cylinder via bolts.

[0008] Specifically, the tooth tips of the upper sections of the upper mold core A and upper mold core B are both flatly cut to form end faces that mate with the inner wall of the upper mold sleeve of the upper mold assembly.

[0009] Specifically, the diameter of the overflow hole is smaller than the inner diameter of the finished gear.

[0010] Specifically, the base angle of the frustum structure of the lower end face of the upper mold core A and the upper end face of the lower mold core A is 6°, and a 0.05 mm thick circular boss is provided on the end face of the frustum, with a rounded transition between the boss and the end face of the frustum.

[0011] Specifically, the lower outer edge of the mold cylinder is provided with several arc-shaped mounting grooves evenly arranged along the circumference, and the bolts are located in each arc-shaped mounting groove and then connected to the lower template of the press.

[0012] Specifically, the upper surface of the mold base is provided with a stepped portion that mates with the lower surfaces of the die A and die B.

[0013] Specifically, the outer edge of the upper end of the lower mold outer ring is provided with a stepped portion that cooperates with the pressure ring.

[0014] Specifically, the upper circumference of the lower mold core pad is chamfered, and the inner diameter of the mold base is set as a cone shape that matches the chamfered structure of the lower mold core pad.

[0015] Due to the adoption of the technical solution described above, this utility model has the following advantages: The mold structure of this utility model can ensure near-net-shape forming of parts by cold extrusion, shorten the processing cycle, improve production efficiency, increase material utilization, reduce production costs, and improve the hardness and tensile strength of parts, thereby improving the mechanical properties of the parts themselves. It solves the problem of incomplete corner filling and low mold life after one-time closed-die forging of spur gears. Attached Figure Description

[0016] Figure 1 This is an overall schematic diagram of the assembly extrusion die core component of the utility model.

[0017] Figure 2 yes Figure 1 A cross-sectional view.

[0018] Figure 3 This is a schematic cross-sectional view of the assembly of the precision forging die core component of this utility model.

[0019] Figure 4 This is a schematic diagram of the upper mold core A of this utility model.

[0020] Figure 5 This is a partial structural diagram of the boss at the end face of the lower mold core A of this utility model.

[0021] Figure 6 This is a schematic diagram of the concave mold A of this utility model.

[0022] Figure 7 This is a schematic diagram of the upper mold core B of this utility model.

[0023] Figure 8 This is a schematic diagram of the lower mold core B of this utility model.

[0024] Figure 9 This is a comparison diagram of the workpiece of this utility model in four states: a, b, c, and d. Among them, a is the blank, b is after pre-forging, c is after precision forging, and d is the finished product after machining.

[0025] In the diagram: 1-Upper mold sleeve, 2-Upper mold locking nut, 31-Upper mold core A, 32-Upper mold core B, 41-Die A, 42-Die B, 5-Lower mold middle ring, 6-Lower mold outer ring, 71-Lower mold core A, 72-Lower mold core B, 8-Lower mold core pad, 9-Mold base, 10-Fixed middle ring, 11-Lower mold pad, 12-Ejector rod nest, 13-Ejector rod, 14-Upper mold flange, 15-Upper mold pad, 16-Pressure ring, 17-Mold cylinder, 18-Overflow hole, 19-Protrusion, 20-Workpiece. Detailed Implementation

[0026] The present invention will be further explained below with reference to the accompanying drawings and embodiments. However, this explanation should not be construed as limiting the scope of protection of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0027] Combined with appendix Figure 1-9 The forging die for a spur gear shown includes an upper die assembly, an extrusion die core assembly, a precision forging die core assembly, and a lower die assembly; the extrusion die core assembly and the precision forging die core assembly are alternately arranged between the upper die assembly and the lower die assembly.

[0028] The upper mold assembly includes an upper mold sleeve 1, an upper mold flange 14, an upper mold pad 15, and an upper mold locking nut 2. The upper mold sleeve 1 is a cylindrical structure with an installation step on the upper outer edge. The upper mold flange 14 is connected to the upper template of the press through a pressure plate, and the lower outer edge of the upper mold flange 14 is provided with external threads. The upper mold pad 15 is placed inside the upper mold flange 14, and the upper end of the upper mold sleeve 1 is placed inside the upper mold flange 14 below the upper mold pad 15. The upper mold locking nut 2 is placed on the installation step of the upper mold sleeve 1 and is threadedly connected to the upper mold flange 14.

[0029] The extrusion die core assembly includes an upper die core A31, a die cavity A41, and a lower die core A71. The upper die core A31 is located within the center of the upper die sleeve 1, and the lower die core A71 is concentrically located within the center of the die cavity A41. Both the upper die core A31 and the lower die core A71 are gear-shaped structures. The lower end face of the upper die core A31 and the upper end face of the lower die core A71 both feature identical frustum structures. The base angle is 6°, and a 0.05 mm thick circular boss is provided on the end face of the frustum. The boss and the end face of the frustum are connected by an arc transition. The die A41 is located in the lower die middle ring 5 of the lower die assembly. The die A41 is a cylindrical structure with a tapered outer edge. The inner wall of the die A41 is provided with tooth grooves that match the teeth on the lower outer edge of the upper die core A31 and the teeth on the outer edge of the lower die core A71. The tooth thickness and root circle of the tooth groove of the die A41 are smaller than the size of the finished gear.

[0030] The precision forging die core assembly includes an upper die core B32, a die cavity B42, and a lower die core B72. Upper die core B32 and upper die core A31 are alternately arranged within the center of the upper die sleeve 1. Lower die core B72 and upper die core B32 are concentrically arranged within the center of the die cavity B42. Upper die core B32 is a hollow gear column structure, and lower die core B72 is a gear column structure. Overflow holes 18 are provided at the lower end of upper die core B32 and the upper end of lower die core B72. The diameter of the overflow holes 18 is smaller than the inner diameter of the finished gear. Upper die core B32... Both the lower end face and the upper end face of the lower mold core B72 are uniformly provided with protrusions 19 that match the shape of the oil grooves on both ends of the finished gear around the overflow hole 18; the die B42 and the die A41 are alternately arranged in the lower mold middle ring 5 of the lower mold assembly. The die B42 is a cylindrical structure with a tapered outer edge. The inner wall of the die B42 is provided with tooth grooves that match the teeth on the lower outer edge of the upper mold core B32 and the teeth on the outer edge of the lower mold core B72; the tooth thickness and tooth root circle of the tooth groove of the die B42 are consistent with the size of the finished gear.

[0031] Preferably, the tooth tips of the upper sections of the upper mold core A31 and the upper mold core B32 are both flatly cut to form end faces that mate with the inner wall of the upper mold sleeve 1 of the upper mold assembly.

[0032] The lower mold assembly includes a mold cylinder 17, an ejector pin nest 12, an ejector pin 13, a lower mold pad 11, a mold base 9, a center ring 10, a lower mold core pad 8, a lower mold outer ring 6, a lower mold middle ring 5, and a pressure ring 16. The lower outer edge of the mold cylinder 17 has several arc-shaped mounting grooves evenly distributed around its circumference. Bolts are located in each arc-shaped mounting groove and connected to the lower mold platen of the press. A mounting hole is located at the center of the bottom of the mold cylinder 17. The ejector pin nest 12 is interference-fitted into the mounting hole, and the ejector pin 13 passes through the ejector pin nest 12. The lower mold pad 11 is located at the bottom of the mold cylinder 17, and a through hole corresponding to the inner hole of the ejector pin nest 12 is located in the center of the lower mold pad 11 via the center ring 10. The upper surface of the mold base 9 has a mating surface with the lower surfaces of the die A41 and die B42. The stepped portion of the mold base 9 has a variable diameter inner hole structure; the lower mold core pad 8 is set inside the bottom of the mold base 9, and the upper circumference of the lower mold core pad 8 is set with a chamfered structure. The variable diameter part of the inner hole of the mold base 9 is set with a tapered shape that matches the chamfered structure of the lower mold core pad 8; the lower mold core A71 or the lower mold core B72 is alternately set on the lower mold core pad 8 inside the mold base 9. The lower mold core A71 and the lower mold core B72 both protrude from the upper end of the mold base 9 and are located in the corresponding concave mold A41 and concave mold B42 respectively; the concave mold A41 or the concave mold B42 is alternately set inside the lower mold middle ring 5, and the lower mold outer ring 6 is set outside the lower mold middle ring 5. The upper outer edge of the lower mold outer ring 6 is provided with a stepped portion that cooperates with the pressure ring 16. The pressure ring 16 is set outside the lower mold outer ring 6, and the pressure ring 16 is connected to the upper end ring surface of the mold cylinder 17 by bolts.

[0033] The assembly sequence of the forging die for spur gears of this utility model is as follows: First, insert the upper die core A31 into the upper die sleeve 1 with an interference fit, with the upper end face of the upper die core A31 flush with the upper end face of the upper die sleeve 1. Then, insert the upper die pad 15 into the upper die flange 14 with a clearance fit. Next, insert the assembled upper die sleeve 1 into the upper die flange 14 below the upper die pad 15 and fix it with the upper die locking nut 2. Connect the upper die assembly to the upper template of the press. Then, press the ejector rod nest 12 into the mounting hole at the bottom of the die cylinder 17 with an interference fit. Then, insert the lower die pad 11 and the centering ring 10 into the die cylinder 17 with a clearance fit. Finally, place the lower die core pad 8 at the center of the lower die pad 11 and the centering ring 10, and place the die base 9 in the center of the lower die cylinder 17. Place the die pad 11 on the die pad plate and position the lower die core pad 8 inside the die base 9, with the lower end of the die base 9 located inside the center hole of the center ring 10; press the die cavity A41 and the lower die center ring 5 together with an interference fit; heat-fit the lower die outer ring 6 onto the lower die center ring 5; place the assembled die cavity A41, lower die center ring 55, and lower die outer ring 6 on the die base 9, with the die cavity A41 positioned on the stepped portion at the upper end of the die base 9; place the lower die core A71 inside the die cavity A41, with its lower end positioned on the lower die core pad 8 inside the die base 9; fasten the pressure ring 16 onto the stepped portion at the upper end of the lower die outer ring 6, and connect the pressure ring 16 to the die cylinder 17 using bolts; fix the assembled die cylinder 17 to the lower die platen of the press using bolts; complete the installation of the extrusion die core assembly, the upper die assembly, and the lower die assembly.

[0034] During operation, the blank workpiece is placed on the lower die core A71 in the die cavity A41. The machine tool slide moves the upper die assembly downwards, and the upper die core A31 enters the die cavity A41. The blank workpiece is subjected to pressure and is squeezed within the closed space formed by the upper die core A31, the die cavity A41, and the lower die core A71, resulting in plastic deformation and achieving a pre-forged workpiece with a structure consistent with the closed space. The machine tool slide returns and moves upwards, causing the upper die assembly to move, making the upper die core A31 leave the die cavity A41 until there is enough space to remove the workpiece. After the machine tool slide stops moving, the lower ejector cylinder of the machine tool moves upwards to eject the workpiece. 13. The lower die core pad 8 is pushed upward along the inner wall of the die base 9 through the push rod nest 12 and the lower die pad 11. The lower die core pad 8 drives the lower die core A71 to move upward in the die base 9. The pre-forged workpiece on the lower die core A71 moves upward until the pre-forged workpiece is pushed out of the die cavity A41 and the lower push cylinder stops moving. Then the pre-forged workpiece is removed and placed in the turnover container. The pre-forging of all blank workpieces is completed in the above manner. Under the extrusion of the frustum structure of the upper die core A31 and the lower die core A71 end faces, the two ends of the pre-forged workpiece form corresponding recessed structures, and the outer edge of the pre-forged workpiece produces gear teeth.

[0035] After the pre-forging process is completed, the extrusion die core assembly is taken out. The precision forging die core assembly is then assembled with the upper die assembly and the lower die assembly according to the above assembly method. The pre-forged workpiece is then placed into the die cavity B42. Following the same steps as the pre-forging process, the pre-forged workpiece is machined in the die cavity B42 to the finished size of the gear teeth and oil grooves. The inner hole is then machined by simple supplementary machining to obtain the finished workpiece.

[0036] The parts of this utility model not described in detail are existing technologies.

[0037] The embodiments selected herein for the purpose of disclosing the inventive objectives of this utility model are currently considered appropriate; however, it should be understood that this utility model is intended to include all variations and modifications of the embodiments that fall within the scope of this concept and utility model.

Claims

1. A forging die for spur gears, characterized in that: It includes an upper die assembly, an extrusion die core assembly, a precision forging die core assembly, and a lower die assembly; the extrusion die core assembly and the precision forging die core assembly are alternately arranged between the upper die assembly and the lower die assembly; The extrusion die core assembly includes an upper die core A, a concave die A, and a lower die core A. The upper die core A is located at the center of the upper die assembly, and the lower die core A is concentrically located within the center of the concave die A. Both the upper die core A and the lower die core A are gear column structures, and the lower end face of the upper die core A and the upper end face of the lower die core A both have the same frustum structure protruding from them. The concave die A is located at the center of the lower die assembly. The concave die A is a cylindrical structure with a tapered outer edge. The inner wall of the concave die A has tooth grooves that match the teeth on the lower outer edge of the upper die core A and the teeth on the outer edge of the lower die core A. The tooth thickness and root circle of the tooth grooves in the concave die A are both smaller than the size of the finished gear. The precision forging die core assembly includes an upper die core B, a die cavity B, and a lower die core B. The upper die core B is located at the center of the upper die assembly, and the lower die core B is concentrically located within the center of the die cavity B. The upper die core B is a hollow gear column structure, and the lower die core B is also a gear column structure. Both the lower end of the upper die core B and the center of the upper end of the lower die core B are provided with overflow holes. The lower end face of the upper die core B and the upper end face of the lower die core B are uniformly provided with protrusions around the overflow holes, which match the shape of the oil grooves on both ends of the finished gear. The die cavity B is located at the center of the lower die assembly. The die cavity B is a cylindrical structure with a tapered outer edge. The inner wall of the die cavity B is provided with tooth grooves that match the teeth on the lower outer edge of the upper die core B and the teeth on the outer edge of the lower die core B. The tooth thickness and root circle of the tooth grooves of the die cavity B are consistent with the dimensions of the finished gear.

2. The forging die for spur gears according to claim 1, characterized in that: The upper mold assembly includes an upper mold sleeve, an upper mold flange, an upper mold pad, and an upper mold locking nut. The upper mold sleeve is a cylindrical structure with an installation step on its upper outer edge. Upper mold core A or upper mold core B is alternately arranged in the center of the upper mold sleeve. The upper mold flange is connected to the upper template of the press through a pressure plate, and the lower outer edge of the upper mold flange is provided with external threads. The upper mold pad is arranged inside the upper mold flange, and the upper end of the upper mold sleeve is arranged inside the upper mold flange below the upper mold pad. The upper mold locking nut is arranged on the installation step of the upper mold sleeve and is threadedly connected to the upper mold flange.

3. The forging die for spur gears according to claim 1, characterized in that: The lower mold assembly includes a mold cylinder, a push rod nest, a push rod, a lower mold pad, a mold base, a center ring, a lower mold core pad, a lower mold outer ring, a lower mold middle ring, and a pressure ring. The mold cylinder is connected to the lower mold platen of the press via bolts and a pad. A mounting hole is provided at the center of the bottom of the mold cylinder. The push rod nest is interference-fitted into the mounting hole, and the push rod passes through the push rod nest. The lower mold pad is located at the bottom of the mold cylinder, and a through hole corresponding to the inner hole of the push rod nest is provided in the middle of the lower mold pad. The mold base is located at the center of the lower mold pad via a center ring, and the inner hole of the mold base has a variable diameter structure. The lower mold core pad is located at the bottom of the mold base. Lower mold core A or lower mold core B is alternately located on the lower mold core pad in the mold base, and lower mold core A or lower mold core B is located through the upper end of the mold base. Die A or die B is alternately located in the lower mold middle ring, the lower mold outer ring is located outside the lower mold middle ring, and the pressure ring is located outside the lower mold outer ring. The pressure ring is connected to the upper end ring surface of the mold cylinder via bolts.

4. The forging die for spur gears according to claim 1, characterized in that: The tooth tips of the upper sections of the upper mold core A and upper mold core B are both flatly cut to form end faces that mate with the inner wall of the upper mold sleeve of the upper mold assembly.

5. The forging die for spur gears according to claim 1, characterized in that: The diameter of the overflow hole is smaller than the inner diameter of the finished gear.

6. The forging die for spur gears according to claim 1, characterized in that: The base angle of the frustum structure of the lower end face of the upper mold core A and the upper end face of the lower mold core A is 6°. A 0.05 mm thick circular boss is provided on the end face of the frustum, and the boss and the end face of the frustum are connected by an arc transition.

7. The forging die for spur gears according to claim 3, characterized in that: The lower outer edge of the mold cylinder is evenly provided with several arc-shaped mounting grooves along the circumference, and the bolts are located in each arc-shaped mounting groove and then connected to the lower template of the press.

8. The forging die for spur gears according to claim 3, characterized in that: The upper surface of the mold base is provided with a stepped portion that mates with the lower surfaces of the die A and die B.

9. The forging die for spur gears according to claim 3, characterized in that: The outer edge of the upper end of the lower mold outer ring is provided with a stepped portion that cooperates with the pressure ring.

10. The forging die for spur gears according to claim 3, characterized in that: The upper circumference of the lower mold core pad is chamfered, and the inner diameter of the mold base is tapered to match the chamfered structure of the lower mold core pad.

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