A high-module spur gear forging with full teeth and its forming device

Abstract

A forged high-module spur gear includes a half-tooth high step and a full-tooth high step. The thickness of the half-tooth high step is not less than the height of the transition arc between two adjacent full-tooth high steps. The tooth profile of the forged high-module spur gear with the full-tooth high step has a uniform difference from the tooth profile of the machined high-module gear part. The metal flow lines of the tooth profile of the full-tooth high step are continuously distributed along the tooth profile. The upper tooth-shaped punch of the forming device is connected to the upper slide of the press through a transfer mechanism. The upper tooth-shaped punch is used to extrude the metal billet in the lower die assembly. During the extrusion process, the forging is prepared by the left and right movement of the symmetrically arranged left and right die assemblies. The forging prepared by this invention can ensure that the metal flow lines are distributed along the part profile after machining, and there is basically no cutting or exposure of the metal flow lines, which greatly improves the strength of the gear and can meet the needs of engineering machinery, marine equipment, and aerospace equipment for high-load, large-module gears.

Description

Technical Field

[0001] This invention relates to the field of gear manufacturing technology, specifically to a full-tooth high-module gear forging and its forming device. Background Technology

[0002] Gears are crucial components in mechanical devices and are one of the fundamental core components of transmission machinery. Their main function is to transmit power and motion, and to change the magnitude and direction of speed and torque. With the development of machine tool technology, gear shaping, hobbing, and grinding equipment have become increasingly precise, and gear processing technology has developed rapidly. For gears without special usage requirements, they can be directly machined from blank metal, followed by heat treatment and finishing. For gears with special operating conditions or ultimate load requirements, forging is necessary to form streamlined tooth profiles to further improve the mechanical properties of the teeth. For small module gears with low tooth profiles (m≤4.5), cold forging or hot forging methods can be used for direct extrusion forming. The blank can fill the die cavity through a short radial flow, and the die life and friction can meet the forming requirements. Large-module gears (m≥5) with high tooth profiles generally have a large volume. If hot forging is used to process the tooth profile, a large volume of blank metal needs to flow a long distance to fill the full-height mold cavity. Due to the prolonged contact between the high-temperature blank and the mold, the mold's mechanical strength rapidly decreases due to temperature rise. Simultaneously, a large amount of metal flows rapidly at the tooth root, and the lubricant at the tooth root disappears quickly due to excessive friction, leading to increased friction and difficulty in metal flow. Ultimately, this causes rapid deformation and failure at the mold root, making it impossible to form a full-height, ultra-large-module spur gear forging. One proposed solution is to forge a portion of the forging material into a half-tooth depth forging, such as... Figure 2 As shown, semi-deep forging reduces the metal flow distance and ensures die life, but the flow lines near the tooth root are cut off after machining, failing to achieve the goal of improving gear performance. The demand for high-load, ultra-large module gears (m≥10) is increasing in the fields of engineering machinery, marine equipment, and aerospace equipment, necessitating the development of a suitable ultra-large module gear. Summary of the Invention

[0003] To overcome the above shortcomings, the present invention provides a full-tooth high-module gear forging and its forming device, which realizes the batch forming of full-tooth high-module spur gears. The metal flow lines of the formed gear are distributed along the full-tooth high-module profile line, thereby improving the gear load-bearing capacity.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A forged spur gear with a high full-tooth module includes a half-tooth high step and a full-tooth high step. The thickness of the half-tooth high step is not less than the height of the transition arc between two adjacent full-tooth high steps. The tooth profile of the forged spur gear with a high full-tooth module has a uniform difference from the tooth profile of the machined high-module gear part. The metal flow lines of the tooth profile of the full-tooth high step are continuously distributed along the tooth profile.

[0006] A forming device for forging high-module spur gears with full teeth includes an upper die assembly, a lower die assembly, a left die assembly, and a right die assembly. The upper die assembly is an upper tooth-shaped punch, which is connected to the upper slide of a press via a transfer mechanism. The upper tooth-shaped punch is used to extrude metal billets within the lower die assembly. During the extrusion process, the forging is prepared by the left and right movements of the symmetrically arranged left and right die assemblies.

[0007] Further optimization involves the lower die assembly comprising a die base, a die cover plate, an upper toothed die, a lower toothed die, a stop pin, a lower toothed punch, and a square ejector pin. The lower toothed die and the upper toothed die are sequentially installed from bottom to top in the circular stepped hole at the upper end of the die base. The outer periphery of the lower toothed die and the upper toothed die forms a semi-circular groove, which, together with the semi-circular groove in the stepped hole of the die base, forms a circular hole. The stop pin is inserted into the circular hole. The lower toothed punch is installed in the die cavity of the lower toothed die. The bottom of the lower toothed punch is connected to a square ejector pin, which is inserted into a square hole on the lower end face of the die base. The die cover plate is installed on the upper end of the upper toothed die, and the die cover plate is fixed to the upper end face of the die base to fix the upper toothed die.

[0008] Further optimization involves the upper toothed die and the lower toothed die having their central axes and semi-circular grooves corresponding, the tooth shapes of the upper toothed die and the lower toothed die corresponding to each other, the square flange at the head of the square push rod connecting to the square positioning groove of the lower toothed punch, the lower toothed punch passing through the lower toothed die, and the lower end of the square push rod being inserted into the square guide rod hole on the lower end face of the die base.

[0009] Further optimization involves the left mold assembly comprising a lower left pull plate, a lower left connecting plate, a lower left hydraulic cylinder, an upper left connecting plate, an upper left hydraulic cylinder, and an upper left pull plate. The lower left pull plate and the upper left pull plate are inserted into rectangular holes at the left end of the mold base. A rectangular groove is provided in the middle of the right side of the upper left pull plate and the lower left pull plate. The left side of the upper left pull plate is connected to the upper left connecting plate. The upper left connecting plate is connected to the cylinder heads of the upper left hydraulic cylinders at both ends of the upper left pull plate. Two upper left hydraulic cylinders are fixedly installed in the square groove on the left side of the mold base. A rectangular groove is provided in the middle of the right side of the lower left pull plate. The left side of the lower left pull plate is connected to the lower left connecting plate. The lower left connecting plate is connected to the cylinder heads of the lower left hydraulic cylinders at both ends of the lower left pull plate. Two lower left hydraulic cylinders are fixedly installed in the square groove on the left side of the mold base.

[0010] Further optimization involves the right mold assembly comprising a lower right pull plate, a lower right connecting plate, a lower right hydraulic cylinder, an upper right connecting plate, an upper right hydraulic cylinder, and an upper right pull plate. The upper right pull plate is inserted into the rectangular groove at the right end of the mold base. A rectangular groove is provided in the middle of the left side of the upper right pull plate. The right side of the upper right pull plate is connected to the upper right connecting plate. The upper left connecting plate is connected to the cylinder heads of the upper right hydraulic cylinders at both ends. Two upper right hydraulic cylinders are installed and fixed in the rectangular groove on the right side of the mold base. The lower right pull plate is inserted into the rectangular groove at the right end of the mold base. A rectangular groove is provided in the middle of the left side of the lower right pull plate. The right side of the lower right pull plate is connected to the lower right connecting plate. The lower right connecting plate is connected to the cylinder heads of the lower right hydraulic cylinders at both ends. Two lower right hydraulic cylinders are installed and fixed in the directional holes on the right side of the mold base.

[0011] Further optimization involves the metal blank's outline being △t1 smaller than the tooth tip circle of the upper toothed die cavity's tooth profile, where △t1 is the blank's expansion after heating plus 1mm; the lower toothed die cavity's outline is △t2 larger than the upper toothed die cavity's outline, where △t2 is the blank's expansion after exiting the upper toothed die plus 1mm.

[0012] Further optimization involves making the widths of the upper left and upper right pull plates greater than the widths of the lower left and lower right pull plates, and making the thicknesses of the upper left and upper right pull plates the same as the full tooth height step of the gear forging.

[0013] The beneficial effects of this invention are as follows:

[0014] Unlike traditional machined gears and semi-deep ultra-large module gears, the full-tooth (full-tooth height) ultra-large module spur gear forgings formed by this invention ensures that the metal flow lines are distributed along the part contour after machining, with virtually no cut-off or exposed metal flow lines, significantly improving gear strength. The forming device of this invention overcomes the problem of intense billet flow during the forming process of full-tooth-height ultra-large module spur gear forgings, which results in short die life and high forming force. This invention divides the forming process into two stages, completed by two-stage dies. The upper stage forms a certain semi-tooth-height billet, and the lower stage forms the full-tooth-height forging. Both dies have low temperature rise and good lubrication, effectively preventing die deformation and failure, improving die life, and enabling the mass production of full-tooth-height ultra-large module spur gear forgings. This invention can meet the needs of engineering machinery, marine equipment, and aerospace equipment for high-load ultra-large module gears. Attached Figure Description

[0015] Figure 1 This is a three-dimensional drawing of a high-module spur gear forging with full teeth according to the present invention;

[0016] Figure 2 Flow diagram of metal forgings for ultra-large module spur gears with full tooth height (full tooth depth);

[0017] Figure 3Flow diagram of metal forgings for ultra-large module spur gears with half tooth depth;

[0018] Figure 4 Simplified diagram of the forming process for forging of high-module spur gears with full teeth;

[0019] Figure 5 This is a three-dimensional drawing of a forging device for high-module spur gears with full teeth (without a die cover plate) according to the present invention.

[0020] Figure 6 Front sectional view of the forming device for forging high-module spur gears with full teeth;

[0021] Figure 7 Top sectional view of the forming device for forging high-module spur gears;

[0022] Figure 8 Schematic diagram of the forming device operation during the forming process of a full-tooth high-module spur gear forging;

[0023] Figure 9 Schematic diagram of the demolding process of a forged high-module spur gear;

[0024] Figure 10 Comparison diagram of upper toothed die, lower toothed die, and blank outline;

[0025] Figure 11 Schematic diagram showing the connection between the upper toothed die and the square ejector pin;

[0026] Attached reference numerals: 1. Square ejector pin; 2. Die base; 3. Lower left pull plate; 4. Lower left connecting plate; 5. Lower left hydraulic cylinder; 6. Upper left connecting plate; 7. Upper left hydraulic cylinder; 8. Upper left pull plate; 9. Stop pin; 10. Die cover plate; 11. Upper toothed punch; 12. Upper toothed die; 13. Blank; 14. Lower toothed die; 15. Lower toothed punch; 16. Upper right connecting plate; 17. Upper right hydraulic cylinder; 18. Upper right pull plate; 19. Lower right hydraulic cylinder; 20. Right... Lower connecting plate, 21. Right lower pull plate, 101. Half-tooth high step, 102. Full-tooth high step, 103. Transition arc, 200. Tooth profile of ultra-large module gear parts after machining, 201. Tooth profile of ultra-large module gear forging with full tooth height, 202. Tooth profile of ultra-large module gear forging with half tooth depth, 300. Forging outlet, 401. Lower tooth profile die cavity profile, 402. Upper tooth profile die cavity profile, 403. Blank profile. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be described in detail below with reference to specific embodiments. The following embodiments are implemented based on the technical solutions of the present invention, and provide detailed implementation methods and specific operation processes. However, the present invention can also be implemented in other ways different from those described herein, so the scope of protection of the present invention is not limited to the following embodiments.

[0028] A forged spur gear with a high module (40) and 13 teeth is disclosed. It includes a half-tooth high step 101 and a full-tooth high step 102, with countersunk holes on both end faces as required for gear part machining. The thickness of the half-tooth high step 101 is not less than the height of the transition arc 103 between the two steps. The tooth profile 201 of the full-tooth high step 102 has a uniform difference (machining allowance) from the tooth profile 200 of the machined high module gear part. The metal flow lines of the tooth profile of the full-tooth high step 102 are distributed along the tooth profile, without any cut-off or exposed ends. The half-tooth high step 101 is required for the process and will be completely or partially removed during subsequent machining according to the gear part drawings.

[0029] A forging device for high-module spur gears includes an upper die assembly, a lower die assembly, a left die assembly, and a right die assembly. The upper die assembly is an upper tooth-shaped punch 11, which is connected to the upper slide of the press via a transition mechanism. The lower die assembly includes a square ejector rod 1, a die base 2, a stop pin 9, a die cover plate 10, an upper tooth-shaped die 12, a lower tooth-shaped die 14, and a lower tooth-shaped punch 15. The lower toothed die 14 and the upper toothed die 12 are sequentially installed in the circular stepped hole at the upper end of the die base 2. The stop pin 9 is inserted into the semi-circular groove formed by the outer circle of the lower toothed die 14 and the upper toothed die 12 and the semi-circular groove in the stepped hole of the die base 2 to form a circular hole. The lower toothed punch 15 is installed in the cavity of the lower toothed die 14. The lower toothed punch 15 is connected to the square ejector rod 1. The square ejector rod 1 is inserted into the square hole at the lower end face of the die base 2. The die cover plate 10 is installed on the upper end of the upper toothed die 12 and is fixed to the upper end face of the die base 2 to fix the upper toothed die 12.

[0030] The left mold assembly includes a lower left pull plate 3, a lower left connecting plate 4, a lower left cylinder 5, an upper left connecting plate 6, an upper left cylinder 7, and an upper left pull plate 8. The upper left pull plate 8 is inserted into the rectangular hole at the left end of the mold base 2. A rectangular groove is provided in the middle of the right side of the upper left pull plate 8. The left side of the upper left pull plate 8 is connected to the upper left connecting plate 6. The upper left connecting plate 6 is connected to the cylinder heads of the upper left cylinders 7 at both ends. The two upper left hydraulic cylinders are installed and fixed in the square groove on the left side of the mold base 2. The lower left pull plate 3 is inserted into the rectangular hole at the left end of the mold base 2. A rectangular groove is provided in the middle of the right side of the lower left pull plate 3. The left side of the lower left pull plate 3 is connected to the lower left connecting plate 4. The lower left connecting plate 4 is connected to the cylinder heads of the lower left cylinders 5 at both ends. The two lower left hydraulic cylinders 5 are installed and fixed in the square groove on the left side of the mold base 2. The right mold assembly includes a lower right pull plate 21, a lower right connecting plate 20, a lower right hydraulic cylinder 19, an upper right connecting plate 16, an upper right hydraulic cylinder 17, and an upper right pull plate 18. The upper right pull plate 18 is inserted into the rectangular groove at the right end of the mold base 2. A rectangular groove is provided in the middle of the left side of the upper right pull plate 18. The right side of the upper right pull plate 18 is connected to the upper right connecting plate 16. The upper right connecting plate 16 is connected to the cylinder heads of the upper right hydraulic cylinders 17 at both ends. The two upper right hydraulic cylinders 17 are installed and fixed in the rectangular groove on the right side of the mold base 2. The lower right pull plate 21 is inserted into the rectangular groove at the right end of the mold base 2. A rectangular groove is provided in the middle of the left side of the lower right pull plate 21. The right side of the lower right pull plate 21 is connected to the lower right connecting plate 20. The lower right connecting plate 20 is connected to the cylinder heads of the lower right hydraulic cylinders 19 at both ends. The two lower right hydraulic cylinders 19 are installed and fixed in the directional holes on the right side of the mold base 2.

[0031] In the forming device, the semi-circular grooves on the outer circumferences of the upper toothed die 12 and the lower toothed die 14 are positionally related to the cavities of the upper toothed die 12 and the lower toothed die 14, preventing axial rotation of the upper and lower toothed dies and causing misalignment of the teeth. After the central axes and semi-circular grooves of the upper toothed die 12 and the lower toothed die 14 are aligned, the teeth of the upper toothed die 12 and the lower toothed die 14 correspond to each other. The square flange at the head of the square ejector rod 1 is connected to the square positioning groove of the lower toothed punch 15. The lower part of the square ejector rod is inserted into the square guide rod hole on the lower end face of the mold base 2. The position of the square positioning groove should ensure that the lower toothed punch 15 can pass smoothly through the lower toothed die 14. This structure can ensure that the square ejector rod 1 and the lower toothed punch 15 connected to it will not rotate. Furthermore, the square shape of the square ejector pin 1 determines the position of the lower toothed punch 15 to prevent axial rotation. This is because the lower toothed punch 15 and the lower toothed die 14 will separate during the forming process, and positioning is required during resetting to prevent interference between the lower toothed die 14 and the lower toothed punch 15.

[0032] In the forming device, the blank contour line 403 is △t1 smaller than the tooth tip circle of the upper toothed die cavity contour, where △t1 is the expansion of the blank after heating plus 1mm. This structure ensures that the blank is smoothly placed into the upper toothed die cavity 12 without damaging the lubricant attached to the tooth root. The lower toothed die cavity contour line 401 of the lower toothed die 14 is △t2 larger than the upper toothed die cavity contour line 402 of the upper toothed die 12, where △t2 is the expansion of the blank after exiting the upper toothed die plus 1mm. This structure ensures that the blank does not come into contact with the lower toothed die cavity after exiting the upper toothed die 12, allowing the lubricant attached to it to be retained, which is beneficial to the deformation behavior of the blank in the lower toothed die 14.

[0033] In the forming device, the widths of the upper left pull plate 8 and the upper right pull plate 18 are greater than the widths of the lower left pull plate 3 and the lower right pull plate 21, and the thicknesses of the upper left pull plate 8 and the upper right pull plate 18 are equal to the thickness of the full tooth height step 102 of the gear forging. During the movement of the pull plate, this structure ensures that the weight of the upper pull plate is not entirely borne by the lower pull plate, but part of the weight is borne by the groove step of the mold base 1, making the pull plate move flexibly and the pressure of the pull plate cylinder stable.

[0034] The foregoing has shown and described the main features, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention based on actual circumstances without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A forming device for forging high-module spur gears with full teeth, characterized in that, It includes an upper die assembly, a lower die assembly, a left die assembly and a right die assembly. The upper die assembly is an upper toothed punch (11). The upper toothed punch (11) is connected to the upper slide of the press through a transfer mechanism. The upper toothed punch (11) is used to extrude the metal billet (13) in the lower die assembly. During the extrusion process, the forging is prepared by the left and right movement of the symmetrically arranged left and right die assemblies. The lower die assembly includes a die base (2), a die cover plate (10), an upper toothed die (12), a lower toothed die (14), a stop pin (9), a lower toothed punch (15), and a square ejector pin (1). The lower toothed die (14) and the upper toothed die (12) are installed sequentially from bottom to top in the circular stepped hole at the upper end of the die base (2). The outer periphery of the lower toothed die (14) and the upper toothed die (12) forms a semi-circular groove, which is connected to the die base (2). The semi-circular groove in the stepped hole forms a round hole. The stop pin (9) is inserted into the round hole. The lower tooth punch (15) is installed in the cavity of the lower tooth die (14). The bottom of the lower tooth punch (15) is connected to the square push rod (1). The square push rod (1) is inserted into the square hole on the lower end face of the mold base. The die cover plate (10) is installed on the upper end of the upper tooth die (12). The die cover plate (10) is fixed to the upper end face of the mold base (2) to fix the upper tooth die (12). The left mold assembly includes a lower left pull plate (3), a lower left connecting plate (4), a lower left cylinder (5), an upper left connecting plate (6), an upper left cylinder (7), and an upper left pull plate (8). The lower left pull plate (3) and the upper left pull plate (8) are inserted into the rectangular hole at the left end of the mold base (2). A rectangular groove is provided in the middle of the right side of the upper left pull plate (8) and the lower left pull plate (3). The left side of the upper left pull plate (8) is connected to the upper left connecting plate (6). The upper left connecting plate (6) is connected to the upper left connecting plate (7). The upper left cylinder (7) of the front and rear ends of the pull plate (8) is connected to the cylinder head, and the two upper left hydraulic cylinders (7) are fixedly installed in the square groove on the left side of the mold base (2); a rectangular groove is provided in the middle right side of the lower left pull plate (3), the left side of the lower left pull plate (3) is connected to the lower left connecting plate (4), the lower left connecting plate (4) is connected to the cylinder head of the lower left cylinder (5) at the front and rear ends of the lower left pull plate (3), and the two lower left hydraulic cylinders (5) are fixedly installed in the square groove on the left side of the mold base (2); The blank outline (403) of the metal blank (13) is △t1 smaller than the tooth tip circle of the tooth outline (402) of the upper tooth cavity of the upper tooth die (12), where △t1 is the amount of expansion of the blank after heating plus 1mm. The lower toothed die cavity contour line (401) of the lower toothed die (14) is △t2 larger than the upper toothed die cavity contour line (402), where △t2 is the expansion amount of the blank after it exits the upper toothed die plus 1mm; The forging of a full-tooth high-module spur gear prepared by the forming device includes a half-tooth high step (101) and a full-tooth high step (102). The thickness of the half-tooth high step (101) is not less than the height of the transition arc (103) between two adjacent full-tooth high steps (102). The tooth profile (201) of the full-tooth high step (102) of the forging of the full-tooth high-module spur gear has a uniform difference from the tooth profile (200) of the machined high-module gear part. The tooth profile metal flow lines of the full-tooth high step (102) are continuously distributed along the tooth profile.

2. The forming apparatus for a full-tooth high-module spur gear forging as described in claim 1, characterized in that, The upper toothed die (12) and the lower toothed die (14) have their central axes and semi-circular grooves corresponding. The tooth shapes of the upper toothed die (12) and the lower toothed die (14) correspond to each other. The square flange at the head of the square push rod (1) is connected to the square positioning groove of the lower toothed punch (15). The lower toothed punch (15) passes through the lower toothed die (14). The lower end of the square push rod (1) is inserted into the square guide rod hole on the lower end face of the mold base (2).

3. The forming apparatus for a full-tooth high-module spur gear forging as described in claim 1, characterized in that, The right mold assembly includes a lower right pull plate (21), a lower right connecting plate (20), a lower right cylinder (19), an upper right connecting plate (16), an upper right cylinder (17), and an upper right pull plate (18). The upper right pull plate (18) is inserted into the rectangular groove at the right end of the mold base (2). A rectangular groove is provided in the middle of the left side of the upper right pull plate (18). The right side of the upper right pull plate (18) is connected to the upper right connecting plate (16). The upper right connecting plate (16) is connected to the upper right cylinders (17) at both ends. The head is connected, and the two upper right oil cylinders (17) are installed and fixed in the square groove on the right side of the mold base (2); the lower right pull plate (21) is inserted into the rectangular groove at the right end of the mold base (2), and a rectangular groove is set in the middle of the left side of the lower right pull plate (21). The right side of the lower right pull plate (21) is connected to the lower right connecting plate (20), and the lower right connecting plate (20) is connected to the cylinder head of the lower right oil cylinders (19) at both ends. The two lower right oil cylinders (19) are installed and fixed in the right side direction hole of the mold base (2).

4. The forming apparatus for a full-tooth high-module spur gear forging as described in claim 3, characterized in that, The width of the upper left pull plate (8) and the upper right pull plate (18) is greater than the width of the lower left pull plate (3) and the lower right pull plate (21), and the thickness of the upper left pull plate (8) and the upper right pull plate (18) is the same as the full tooth height step (102) of the gear forging.

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