Deep ion nitriding process for gear with high bearing capacity

Abstract

The invention discloses a deep ion nitriding process for a gear with high bearing capacity, relates to the related field of gear processing, and aims to solve the problems of different nitriding degrees of different parts of the gear and unstable nitriding quality of the gear due to non-uniform distribution after ammonia gas is introduced in the prior art. When the furnace temperature rises to the nitriding temperature, ammonia gas is introduced into the furnace through an ammonia gas introduction pipe and an ammonia gas discharge pipe, the ammonia gas spirally flows upwards and is discharged along the side wall due to the existence of a first spiral channel and a second spiral channel in the ammonia gas discharge pipe, and the ammonia gas is disturbed through a rotating structure; an ammonia gas discharge pipe is rotationally sealed at the upper end in the ammonia gas introduction pipe, a double-helix part is fixed in the ammonia gas discharge pipe, a gas exhaust hole is formed in the pipe wall of the ammonia gas discharge pipe, a self-rotating fan is rotationally connected to the outside of the ammonia gas discharge pipe and comprises rotating fan blades, and the rotating fan blades horizontally correspond to the gas exhaust hole in position; and horizontal rotating fans are vertically fixed outside the ammonia gas discharge pipe in an array manner.

Description

Technical Field

[0001] The present invention relates to the field related to gear processing, and specifically to a deep ion nitriding process for gears with high load-bearing capacity. Background Technique

[0002] With the rapid development of modern industrial technology, gears, as core components in mechanical transmission systems, have increasingly higher performance requirements. Especially in fields such as aerospace, shipbuilding, heavy machinery, and the automotive industry, more stringent standards have been put forward for aspects such as the load-bearing capacity, wear resistance, fatigue resistance, and control of heat treatment deformation of gears. Although the traditional carburizing and quenching process can meet the strength requirements of gears to a certain extent, problems such as internal oxidation, large distortion, high cost, high energy consumption, and the need for additional gear grinding for high-precision gears limit its wide application in the manufacture of high-performance gears.

[0003] As an effective surface strengthening technology, the nitriding process has gradually emerged in the field of gear manufacturing with its unique advantages. The nitriding process infiltrates active nitrogen atoms into the gear surface to form a high-hardness and high-wear-resistant compound layer, thereby significantly improving the surface hardness and wear resistance of the gear. Compared with carburizing and quenching, the nitriding process has significant advantages such as low treatment temperature, no phase change in the substrate, small distortion, good hot hardness, and high corrosion resistance. Especially ion nitriding technology, as an advanced form of the nitriding process, can more precisely control the nitrided layer structure and obtain more excellent properties by controlling the nitrogen-hydrogen ratio and electrical parameters in the furnace atmosphere; its applied industrial fields include steel, chemical industry, machine tools, automobiles, and energy, etc.

[0004] In the existing deep ion nitriding process for gears, there are some problems; after ammonia gas is introduced, the distribution is uneven, resulting in different nitriding degrees in different parts of the gear, unstable nitriding quality of the gear, reducing the overall performance of the gear, and it is difficult to achieve the ideal effect. Summary of the Invention

[0005] The purpose of the present invention is to provide a deep ion nitriding process for gears with high load-bearing capacity to solve the problems of uneven distribution of ammonia gas after introduction, resulting in different nitriding degrees in different parts of the gear and unstable nitriding quality of the gear as mentioned in the above background technique.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A deep ion nitriding process for gears with high load-bearing capacity, based on a nitriding furnace for deep ion nitriding of gears, includes the following steps:

[0007] Step 1: Perform normalizing or quenching and tempering treatment on the gear, and scrub the gear surface with gasoline and alcohol. Place the treated gear in the gear placement interval formed by the gear placement component, and suspend the gear placement component on the upper end of the lower support inside the furnace chamber of the nitriding furnace.

[0008] Step 2: Set the nitriding furnace to the initial temperature, send nitrogen for exhaust through the nitrogen inlet pipe, and heat it at the same time. After maintaining for a period of time, set the temperature to the nitriding temperature;

[0009] Step 3: When the furnace temperature rises to the nitriding temperature, fill the furnace with ammonia through the ammonia inlet pipe and the ammonia discharge pipe. The presence of the first spiral channel and the second spiral channel in the ammonia discharge pipe makes the ammonia flow upward in a spiral and discharge along the side wall. The ammonia is disturbed by the rotating structure so that it fills the inside of the nitriding furnace hearth and maintains the pressure of the nitriding furnace;

[0010] Step 4: Apply a high-voltage DC power supply. Under the action of the high-voltage electric field, glow discharge occurs. Nitrogen is partially decomposed to form positive ions of nitrogen and hydrogen and electrons. The positive ions of hydrogen and nitrogen accelerate towards the cathode surface. The ions bombard the surface layer of the gear, and the kinetic energy is converted into heat energy to heat the gear. At the same time, cathode sputtering occurs when the ions bombard the surface layer of the gear. The sputtered iron ions combine with nitrogen ions to form iron nitride FeN. FeN reattaches to the surface layer of the gear, and then decomposes into FeN and FeN, and releases nitrogen atoms to diffuse into the gear;

[0011] Step 5: After nitriding is completed, reduce the ammonia pressure and perform denitriding treatment to remove the excess nitrogen atoms on the surface of the gear;

[0012] Step 6: After the denitriding treatment is completed, cut off the power supply and stop heating;

[0013] Step 7: Supply a small amount of ammonia to maintain a positive pressure in the furnace. Wait until the furnace temperature drops below the safe temperature, stop supplying ammonia and take out the furnace;

[0014] Wherein, the upper end inside the ammonia inlet pipe is rotationally sealed with an ammonia discharge pipe, the ammonia discharge pipe extends upward, a double spiral member is fixed inside the ammonia discharge pipe, a first spiral channel and a second spiral channel are formed between the ammonia discharge pipe and the double spiral member, exhaust holes are formed in the pipe wall of the ammonia discharge pipe, and the exhaust holes are communicated with the first spiral channel or the second spiral channel. An automatic rotating fan is rotatably connected to the outside of the ammonia discharge pipe. The automatic rotating fan includes rotating fan blades, and the rotating fan blades are horizontally corresponding to the positions of the exhaust holes. Horizontally rotating fans are vertically and arrayedly fixed outside the ammonia discharge pipe.

[0015] Preferably, the nitriding furnace includes a nitriding furnace main body and a nitriding furnace cover. The nitriding furnace cover is arranged at the upper end of the nitriding furnace main body. The nitriding furnace main body is composed of a nitriding furnace shell, a nitriding furnace lining and a nitriding furnace hearth. The lower end of the nitriding furnace main body is fixed with an ammonia inlet pipe, and one end of the ammonia inlet pipe extends to the lower end inside the nitriding furnace hearth.

[0016] Preferably, an upper fixed column is fixed to the upper end of the ammonia exhaust pipe, and a special-shaped groove is opened in the center of the upper end surface of the upper fixed column. A second drive motor is installed in the center of the upper end of the nitriding furnace cover, and a lower special-shaped embedded rod is installed along the output shaft end of the second drive motor at the lower end of the nitriding furnace cover, and the lower special-shaped embedded rod matches the special-shaped groove.

[0017] Preferably, the outer upper end of the furnace core of the nitriding furnace is rotatably connected to an outer rotating locking disk, and an inner fixed plate is fixed in an array on the inner side of the upper end surface of the outer rotating locking disk. A vertical entry groove is formed on the outer rotating locking disk through the separation of the inner fixed plate, and the lower end surface of the inner fixed plate is sequentially provided with an inclined pressing part, a horizontal pressing part and a limiting part. The connection between the inclined pressing part and the horizontal pressing part has a smooth transition, and a locking groove is formed at the lower end of the horizontal pressing part along the inner edge of the outer rotating locking disk.

[0018] Preferably, a lower embedded disk is provided at the lower end of the nitriding furnace cover, and an outer fixing plate is fixed to the lower end array outside the lower embedded disk. The outer fixing plate matches the horizontal shape of the vertical entry groove, and the height of the outer fixing plate matches the height of the locking groove.

[0019] Preferably, a first driving motor is installed on one side of the nitriding furnace body, a driving gear is installed on the output shaft end of the first driving motor, an outer gear ring is fixed to the outside of the outer rotating locking disk, and the outer gear ring is engaged with the driving gear.

[0020] Preferably, a driving cylinder is installed on the other side of the nitriding furnace body, and a lifting member is fixed to the output rod end of the driving cylinder. The upper end of the lifting member is rotatably connected to an upper rotating member, and the upper rotating member is fixed to the nitriding furnace cover. An actuating rod is fixed to the side of the upper end of the nitriding furnace cover away from the upper rotating member through a fixing seat.

[0021] Preferably, a lower support is welded and fixed to the lower end of the interior of the nitriding furnace, and a gear placement assembly is placed along the upper end of the lower support inside the interior of the nitriding furnace.

[0022] Preferably, the gear placement assembly includes multiple shelf plates, which are composed of multiple ring bodies and connecting rods. A gear placement interval is formed between adjacent shelf plates. An upper hanging ring is fixed to the upper end array of the inner end of the ring body on the uppermost shelf plate. Multiple shelf plates are welded and fixed by outer vertical fixing rods, middle vertical fixing rods and inner vertical fixing rods. A ring array of multiple outer vertical fixing rods passes through the outermost ring body, a ring array of multiple inner vertical fixing rods passes through the innermost ring body, a ring array of multiple middle vertical fixing rods passes through the middle position of the shelf plates, and the middle vertical fixing rods are staggered with the outer vertical fixing rods.

[0023] Preferably, a nitrogen inlet pipe is installed at the lower end of one side of the nitriding furnace body, and an exhaust pipe and an air exhaust pipe are installed on the nitriding furnace cover, and the lower ends of the exhaust pipe and the air exhaust pipe extend into the nitriding furnace.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) In the present invention, the double spiral member in the ammonia discharge pipe forms a first spiral channel and a second spiral channel, so that the ammonia flows upward in a spiral. When the ammonia reaches the exhaust hole, it flows outward through the exhaust hole. Due to the relative rotation relationship between the self-rotating fan and the ammonia discharge pipe, and the relative position of the rotating blades of the self-rotating fan and the exhaust hole, the airflow discharged from the exhaust hole hits the rotating blades, driving the self-rotating fan to rotate and disturbing the ammonia. At the same time, the horizontal rotating fan is driven to rotate under the driving action, and the ammonia can evenly fill the interior of the nitriding furnace, ensuring that all parts of the gear can fully contact the ammonia, improving the nitriding quality, enhancing the hardness and wear resistance of the gear, and significantly improving the bearing capacity of the gear.

[0026] (2) In this invention, during the nitriding process, nitrogen is first exhausted and then ammonia is filled in, which can avoid the influence of other internal gases, and nitrogen can participate in the entire process together with ammonia, ensuring that the gear can be nitrided according to the predetermined process, ensuring the stability of the gear nitriding quality, and further improving the bearing capacity of the gear.

[0027] (3) In this invention, the gears are placed in the gear placement interval formed between adjacent shelf plates, and are inserted between two outer vertical fixing rods and bypass the middle vertical fixing rod, so that the gears are placed in the interval formed by multiple middle vertical fixing rods and multiple inner vertical fixing rods; then the gears are placed in the gear placement interval formed between adjacent shelf plates, and are inserted between two outer vertical fixing rods, so that other gears are placed in the interval formed by multiple outer vertical fixing rods and multiple middle vertical fixing rods. Through the unique gear placement component design, the gears can be placed in the nitriding furnace in an orderly and uniform manner, ensuring that each gear can fully receive the nitriding treatment, greatly improving the consistency of the gear nitriding effect, and thus improving the overall performance and load-bearing capacity of the gears.

[0028] (4) In this invention, a unique locking and opening structure is adopted. By driving the oil cylinder, lifting parts, upper rotating parts and other components to work together, the nitriding furnace cover can be opened and locked quickly and conveniently, which greatly improves the working efficiency. At the same time, through the cooperation of the inner fixing plate and the outer fixing plate, a reliable seal is achieved, which ensures the stability of the working environment in the nitriding furnace and is conducive to improving the nitriding quality of the gears. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the overall structure of the nitriding furnace of the present invention from a main perspective;

[0030] Figure 2 This is a schematic diagram of the overall structure of the nitriding furnace of the present invention from the lower perspective;

[0031] Figure 3 This is the front view of the nitriding furnace of the present invention;

[0032] Figure 4 This is a schematic cross-sectional structure diagram of the nitriding furnace body of the nitriding furnace of the present invention;

[0033] Figure 5 This is an enlarged view of the structure at A of the nitriding furnace of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the double spiral member of the nitriding furnace of the present invention;

[0035] Figure 7 This is an enlarged view of the structure at B of the nitriding furnace of the present invention;

[0036] Figure 8 This is a schematic diagram of the structure of the gear placement assembly of the nitriding furnace of the present invention.

[0037] In the figure: 1, nitriding furnace body; 2, nitriding furnace shell; 3, nitriding furnace lining; 4, nitriding furnace hearth; 5, lower support member; 6, nitrogen inlet pipe; 7, ammonia inlet pipe; 8, ammonia discharge pipe; 9, double spiral member; 10, first spiral channel; 11, second spiral channel; 12, exhaust hole; 13, self-rotating fan; 14, rotating fan blade; 15, upper fixing column; 16, special-shaped groove; 17, outer rotating locking disc; 18, inner fixing plate; 19, vertical inlet groove; 20, inclined pressing part; 21, horizontal pressing part; 22, limiting part; 23, locking groove; 24, outer tooth ring; 25, first driving motor; 26, driving gear; 27, driving oil cylinder; 28, lifting member; 29, upper rotating member; 30, nitriding furnace cover; 31, action rod; 32, waste gas discharge pipe; 33, air discharge pipe; 34, second driving motor; 35, lower special-shaped embedding rod; 36, lower embedding disc; 37, outer fixing plate; 38, gear placement assembly; 39, shelving layer board; 40, upper lifting ring; 41, gear placement interval; 42, outer vertical fixing rod; 43, middle vertical fixing rod; 44, inner vertical fixing rod; 45, horizontal rotating fan. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0039] Please refer to Figures 1-8The present invention provides an embodiment of a deep ion nitriding process for gears with high load-bearing capacity. The process is based on a specific nitriding furnace for deep ion nitriding of gears. The specific steps are as follows:

[0040] Step 1: Gear pretreatment and placement

[0041] First, the gears are normalized or tempered to improve their internal structure and mechanical properties. Then, the gear surface is carefully scrubbed with gasoline and alcohol to remove oil and impurities on the surface and ensure the cleanliness of the gear surface. The treated gears are placed in the gear placement interval 41 formed in the gear placement assembly 38. The gear placement assembly 38 includes a plurality of shelf plates 39, which are composed of a plurality of ring bodies and connecting rods. The gear placement interval 41 is formed between adjacent shelf plates 39. An upper lifting ring 40 is fixed to the upper end array of the inner end ring body on the uppermost shelf plate 39 to facilitate lifting operations. Multiple shelf plates 39 are welded and fixed by outer vertical fixing rods 42, middle vertical fixing rods 43 and inner vertical fixing rods 44. A circular array of multiple outer vertical fixing rods 42 passes through the outermost ring body, a circular array of multiple inner vertical fixing rods 44 passes through the innermost ring body, a circular array of multiple middle vertical fixing rods 43 passes through the middle position of the shelf plates 39, and the middle vertical fixing rods 43 are staggered with the outer vertical fixing rods 42.

[0042] When placing gears, first place the gears in the gear placement interval 41 formed between adjacent shelf plates 39, inserting them between the two outer vertical fixing rods 42 and bypassing the middle vertical fixing rod 43, so that the gears are placed in the interval formed by multiple middle vertical fixing rods 43 and multiple inner vertical fixing rods 44. Gears are placed in sequence until the interval is full. Then, place the gears in the gear placement interval 41 formed between adjacent shelf plates 39, inserting them between the two outer vertical fixing rods 42, so that other gears are placed in the interval formed by multiple outer vertical fixing rods 42 and multiple middle vertical fixing rods 43. Then, the gear placement assembly 38 is hung on the upper end of the lower support member 5 inside the nitriding furnace 4. The lower support member 5 is welded and fixed to the lower end of the nitriding furnace 4 to provide stable support for the gear placement assembly 38. This gear placement method can make the gears more evenly distributed in the nitriding furnace, which is conducive to the uniform penetration of subsequent ammonia gas and improves the consistency of the nitriding effect, thereby improving the overall performance and load-bearing capacity of the gears.

[0043] Step 2: Nitrogen exhaust and heating

[0044] Set the nitriding furnace to the initial temperature, send nitrogen for exhaust through the nitrogen inlet pipe 6, and heat it simultaneously. The nitrogen inlet pipe 6 is installed at the lower end on one side of the nitriding furnace body 1. Sending nitrogen can remove the air in the furnace and create a good environment for subsequent ammonia nitriding. After maintaining for a period of time, set the temperature to the nitriding temperature to provide suitable temperature conditions for gear nitriding. By precisely controlling the nitrogen exhaust and heating processes, the stability of the furnace environment can be ensured, laying a foundation for the smooth progress of the subsequent nitriding process and improving the nitriding quality.

[0045] Step Three: Ammonia Introduction and Diffusion

[0046] When the furnace temperature rises to the nitriding temperature, ammonia is filled into the furnace through the ammonia inlet pipe 7 and the ammonia discharge pipe 8. The ammonia discharge pipe 8 is rotationally sealed at the upper end inside the ammonia inlet pipe 7. A double - helix member 9 is fixed inside the ammonia discharge pipe 8. A first spiral channel 10 and a second spiral channel 11 are formed between the ammonia discharge pipe 8 and the double - helix member 9. Exhaust holes 12 are formed in the wall of the ammonia discharge pipe 8, and the exhaust holes 12 communicate with the first spiral channel 10 or the second spiral channel 11. Ammonia enters the ammonia discharge pipe 8 from the ammonia inlet pipe 7 and then moves upward along the first spiral channel 10 and the second spiral channel 11. When the ammonia reaches the position of the exhaust holes 12, it will flow out through the exhaust holes 12.

[0047] A self - rotating fan 13 is rotatably connected to the outside of the ammonia discharge pipe 8. The self - rotating fan 13 includes rotating fan blades 14, and the rotating fan blades 14 are horizontally corresponding to the positions of the exhaust holes 12. The airflow discharged from the exhaust holes 12 beats the rotating fan blades 14, driving the self - rotating fan 13 to rotate, dispersing the ammonia discharged from the exhaust holes 12 and making the ammonia diffuse outward. In addition, an upper fixing column 15 is fixed to the upper end of the ammonia discharge pipe 8. An irregular groove 16 is formed in the center of the upper end surface of the upper fixing column 15. A second driving motor 34 is installed in the center of the upper end of the nitriding furnace cover 30. A lower irregularly - shaped embedding rod 35 is installed along the output shaft end of the second driving motor 34 at the lower end of the nitriding furnace cover 30, and the lower irregularly - shaped embedding rod 35 matches the irregular groove 16. After the nitriding furnace cover 30 moves downward and is pressed tightly, the lower irregularly - shaped embedding rod 35 is embedded in the irregular groove 16. When the output shaft of the second driving motor 34 rotates, it drives the entire ammonia discharge pipe 8 to rotate along the inner part of the ammonia inlet pipe 7, driving the horizontally - rotating fans 45 fixedly arranged in a vertical array outside the ammonia discharge pipe 8 to rotate. The self - rotating fan 13 will synchronously rotate longitudinally, further diffusing the ammonia inside, making the internal ammonia distribution relatively uniform. This way of ammonia introduction and diffusion can ensure the uniform distribution of ammonia in the nitriding furnace, improve the nitriding efficiency, enable each part of the gear to fully contact ammonia, and enhance the nitriding effect.

[0048] Step Four: Glow Discharge and Ion Bombardment

[0049] A high-voltage DC power supply is connected. Under the action of a high-voltage electric field, glow discharge occurs, and nitrogen is partially decomposed to form positive ions of nitrogen and hydrogen as well as electrons. The positive ions of hydrogen and nitrogen accelerate towards the cathode surface. The ions bombard the surface layer of the gear, and the kinetic energy is converted into heat energy to heat the gear. At the same time, the ions bombard the surface layer of the gear to generate cathode sputtering. The sputtered iron ions combine with nitrogen ions to form iron nitride FeN. FeN reattaches to the surface layer of the gear, then decomposes into Fe2N and Fe3N, and releases nitrogen atoms that diffuse into the gear. This process can form a dense nitrided layer on the gear surface, significantly improving the hardness, wear resistance, and fatigue resistance of the gear, thereby greatly enhancing the bearing capacity of the gear.

[0050] Step Five: Denitriding Treatment

[0051] After nitriding is completed, the ammonia pressure is adjusted to a lower level for denitriding treatment to remove excess nitrogen atoms on the gear surface. The denitriding treatment can avoid problems such as increased brittleness caused by excessive nitrogen atoms on the gear surface, ensure the stable performance of the gear, and improve the service life and bearing capacity of the gear.

[0052] Step Six: Cutting off the Power Supply and Cooling

[0053] After the denitriding treatment is completed, the power supply is cut off to stop heating.

[0054] Step Seven: Ammonia Adjustment and Furnace Discharge

[0055] A small amount of ammonia is supplied to keep the positive pressure inside the furnace. When the furnace temperature drops below the safe temperature, the ammonia supply is stopped and the furnace is discharged. Maintaining the positive pressure can prevent external air from entering the furnace and ensure the quality of the gear. Discharging the furnace below the safe temperature can avoid harm to the operators caused by high temperature and ensure that the performance of the gear is not affected.

[0056] The nitriding furnace of the present invention includes a nitriding furnace main body 1 and a nitriding furnace cover 30. The nitriding furnace cover 30 is arranged at the upper end of the nitriding furnace main body 1. The nitriding furnace main body 1 is composed of a nitriding furnace shell 2, a nitriding furnace lining 3, and a nitriding furnace inner liner 4. An ammonia inlet pipe 7 is fixed at the lower end of the nitriding furnace main body 1, and one end of the ammonia inlet pipe 7 extends to the lower end inside the nitriding furnace inner liner 4. The nitriding furnace shell 2 is formed by welding steel plates and steel sections. The nitriding furnace lining 3 is made of high-strength energy-saving refractory bricks, and a heat-insulating material is arranged between the nitriding furnace lining 3 and the nitriding furnace shell 2. The heating element is composed of a spiral high-temperature resistance wire and is installed on the bricks of the nitriding furnace lining 3, or a gas heating element is used; a cooling structure is also included at the external position of the nitriding furnace inner liner. Since there is no special design for this part of the structure of the nitriding furnace, no specific description is given, and it can be adjusted according to actual needs in combination with existing market products.

[0057] The upper end of the outer part of the nitriding furnace hearth 4 is rotatably connected to an outer rotating locking disc 17. Inside the upper end face of the outer rotating locking disc 17, inner fixing plates 18 are arrayed and fixed. The outer rotating locking disc 17 forms vertical entry slots 19 through the separation by the inner fixing plates 18. On the lower end face of the inner fixing plates 18, an inclined pressing part 20, a horizontal pressing part 21 and a limiting part 22 are sequentially arranged. The connection between the inclined pressing part 20 and the horizontal pressing part 21 has a smooth transition. Inside the outer rotating locking disc 17, a locking slot 23 is formed along the lower end of the horizontal pressing part 21. At the lower end of the nitriding furnace cover 30, a lower embedding disc 36 is provided. Outside the lower end of the lower embedding disc 36, outer fixing plates 37 are arrayed and fixed. The outer fixing plates 37 match the horizontal shape of the vertical entry slots 19, and the height of the outer fixing plates 37 matches the height of the locking slot 23. On one side of the nitriding furnace body 1, a first driving motor 25 is installed. At the output shaft end of the first driving motor 25, a driving gear 26 is installed. An outer toothed ring 24 is fixed outside the outer rotating locking disc 17. The outer toothed ring 24 meshes with the driving gear 26 to realize the rotation of the outer rotating locking disc 17 and complete the locking and opening of the nitriding furnace cover 30.

[0058] On the other side of the nitriding furnace body 1, a driving oil cylinder 27 is installed. At the output rod end of the driving oil cylinder 27, a lifting member 28 is fixed. The upper end of the lifting member 28 is rotatably connected to an upper rotating member 29. The upper rotating member 29 is fixed to the nitriding furnace cover 30. On one side of the nitriding furnace cover 30 far from the upper rotating member 29, an operating rod 31 is fixed through a fixing seat.

[0059] During the locking or opening process: The output rod of the driving oil cylinder 27 drives the lifting member 28 to move upward, thereby driving the nitriding furnace cover 30 to move upward. The staff holds the operating rod 31 by hand and pushes it. The upper rotating member 29 and the nitriding furnace cover 30 rotate along the lifting member 28, and the upper end face of the nitriding furnace hearth 4 is opened, and the gear placing assembly 38 can be hoisted and placed in or taken out.

[0060] The staff holds the operating rod 31 by hand and pushes it, so that the nitriding furnace cover 30 reaches the upper end of the nitriding furnace hearth 4. The output rod of the driving oil cylinder 27 drives the lifting member 28 to move downward, thereby driving the nitriding furnace cover 30 to move downward; the outer fixing plates 37 outside the lower embedding disc 36 enter the outer rotating locking disc 17 along the vertical entry slots 19. The first driving motor 25 drives the driving gear 26 to rotate, and drives the outer rotating locking disc 17 to rotate through the meshing connection relationship between the outer toothed ring 24 and the driving gear 26. The inclined pressing part 20 on the inner fixing plate 18 contacts the upper end face of the outer fixing plate 37 and presses it downward until the outer fixing plate 37 is completely pressed and fixed by the horizontal pressing part 21, realizing the locking function.

[0061] On the nitriding furnace cover 30, an exhaust gas pipe 32 and an air exhaust pipe 33 are installed. The lower ends of the exhaust gas pipe 32 and the air exhaust pipe 33 extend into the nitriding furnace hearth 4.

[0062] Structures such as the nitriding furnace shell 2, the nitriding furnace lining 3, the nitriding furnace liner 4, the first drive motor 25, and the drive oil cylinder 27 are embedded in the area well dug underground.

[0063] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed invention.

Claims

1. A deep ion nitriding process for gears with high load-bearing capacity, which is based on a nitriding furnace for deep ion nitriding of gears, is characterized in that, It includes the following steps: Step 1: Normalize or quenched and tempered the gear, scrub the gear surface with gasoline and alcohol, place the treated gear in the gear placement area (41) formed within the gear placement assembly (38), and suspend the gear placement assembly (38) at the upper end of the lower support member (5) inside the nitriding furnace liner (4); Step 2: Set the nitriding furnace to the initial temperature, send nitrogen for exhaust through the nitrogen inlet pipe (6), and heat simultaneously. After maintaining for a period of time, then set the temperature to the nitriding temperature; Step 3: When the furnace temperature rises to the nitriding temperature, fill ammonia into the furnace through the ammonia inlet pipe (7) and the ammonia discharge pipe (8). The presence of the first spiral channel (10) and the second spiral channel (11) in the ammonia discharge pipe (8) causes the ammonia to flow upward in a spiral and discharge along the side wall. Disturb the ammonia through the rotating structure to make it fill the inside of the nitriding furnace liner (4), and maintain the pressure of the nitriding furnace; Step 4: Apply a high-voltage DC power supply. Under the action of the high-voltage electric field, glow discharge occurs. Nitrogen is partially decomposed to form positive ions of nitrogen and hydrogen and electrons. The positive ions of hydrogen and nitrogen accelerate towards the cathode surface. The ions bombard the gear surface layer, and the kinetic energy is converted into heat energy to heat the gear. At the same time, the ions bombard the gear surface layer to generate cathode sputtering. The sputtered iron ions combine with nitrogen ions to form iron nitride FeN. FeN reattaches to the gear surface layer, and then decomposes into Fe2N and Fe3N, and releases nitrogen atoms to diffuse into the gear; Step 5: After nitriding is completed, reduce the ammonia pressure and perform denitriding treatment to remove excess nitrogen atoms on the gear surface; Step 6: After the denitriding treatment is completed, cut off the power supply and stop heating; Step 7: Supply a small amount of ammonia to keep the positive pressure inside the furnace. Wait until the furnace temperature drops below the safe temperature, stop supplying ammonia and take out the furnace; Wherein, the upper end inside the ammonia inlet pipe (7) is rotationally sealed with the ammonia discharge pipe (8). The ammonia discharge pipe (8) extends upward. A double spiral member (9) is fixed inside the ammonia discharge pipe (8). The first spiral channel (10) and the second spiral channel (11) are formed between the ammonia discharge pipe (8) and the double spiral member (9). The ammonia discharge pipe (8) wall is provided with exhaust holes (12). The exhaust holes (12) are communicated with the first spiral channel (10) or the second spiral channel (11). The outside of the ammonia discharge pipe (8) is rotatably connected with a self-rotating fan (13). The self-rotating fan (13) includes a rotating fan blade (14). The rotating fan blade (14) is horizontally corresponding to the position of the exhaust hole (12). Horizontally rotating fans (45) are vertically and arrayedly fixed outside the ammonia discharge pipe (8).

2. A deep ion nitriding process for gears with high load-bearing capacity according to claim 1, characterized in that: The nitriding furnace includes a nitriding furnace main body (1) and a nitriding furnace cover (30). The nitriding furnace cover (30) is arranged at the upper end of the nitriding furnace main body (1). The nitriding furnace main body (1) is composed of a nitriding furnace shell (2), a nitriding furnace lining (3) and a nitriding furnace liner (4). The lower end of the nitriding furnace main body (1) is fixed with an ammonia inlet pipe (7). One end of the ammonia inlet pipe (7) extends to the lower end inside the nitriding furnace liner (4).

3. A deep ion nitriding process for gears with high load-bearing capacity according to claim 2, characterized in that: The upper end of the ammonia discharge pipe (8) is fixed with an upper fixing column (15). The upper end face of the upper fixing column (15) is centered with a special-shaped groove (16). The upper end of the nitriding furnace cover (30) is centered with a second driving motor (34). The lower end of the nitriding furnace cover (30) is provided with a lower special-shaped embedding rod (35) along the output shaft end of the second driving motor (34). The lower special-shaped embedding rod (35) matches the special-shaped groove (16).

4. A deep ion nitriding process for gears with high load-bearing capacity according to claim 2, characterized in that: The outer upper end of the nitriding furnace liner (4) is rotatably connected with an outer rotating locking disc (17). The inner side of the upper end face of the outer rotating locking disc (17) is fixedly arranged with inner fixing plates (18) in an array. The outer rotating locking disc (17) is formed with vertical entry grooves (19) through the separation of the inner fixing plates (18). The lower end faces of the inner fixing plates (18) are sequentially provided with an inclined pressing part (20), a horizontal pressing part (21) and a limiting part (22). The connection between the inclined pressing part (20) and the horizontal pressing part (21) is smoothly transitioned. The inner side of the outer rotating locking disc (17) forms a locking groove (23) along the lower end of the horizontal pressing part (21).

5. A deep ion nitriding process for gears with high load-bearing capacity according to claim 4, characterized in that: The lower end of the nitriding furnace cover (30) is provided with a lower embedding disc (36). The outer lower end of the lower embedding disc (36) is fixedly arranged with outer fixing plates (37) in an array. The outer fixing plates (37) match the transverse shape of the vertical entry grooves (19). The height of the outer fixing plates (37) matches the height of the locking groove (23).

6. A deep ion nitriding process for gears with high load-bearing capacity according to claim 4, characterized in that: One side of the nitriding furnace body (1) is provided with a first driving motor (25). The output shaft end of the first driving motor (25) is provided with a driving gear (26). The outer side of the outer rotating locking disc (17) is fixed with an outer toothed ring (24). The outer toothed ring (24) meshes with the driving gear (26).

7. A deep ion nitriding process for gears with high load-bearing capacity according to claim 6, characterized in that: The other side of the nitriding furnace body (1) is provided with a driving oil cylinder (27). The output rod end of the driving oil cylinder (27) is fixed with a lifting part (28). The upper end of the lifting part (28) is rotatably connected with an upper rotating part (29). The upper rotating part (29) is fixed with the nitriding furnace cover (30). One side of the upper end of the nitriding furnace cover (30) far from the upper rotating part (29) is fixed with an action rod (31) through a fixing seat.

8. A deep ion nitriding process for gears with high load-bearing capacity according to claim 2, characterized in that: The lower end inside the nitriding furnace liner (4) is welded and fixed with a lower support part (5). A gear placement assembly (38) is placed along the upper end of the lower support part (5) inside the nitriding furnace liner (4).

9. A deep ion nitriding process for gears with high load-carrying capacity according to claim 2, characterized in that: The gear placement assembly (38) includes a plurality of shelf plates (39), and the shelf plates (39) are composed of a plurality of ring bodies and connecting rods. A gear placement interval (41) is formed between adjacent shelf plates (39). An upper hanging ring (40) is fixed to the upper end array of the inner end of the ring body on the uppermost shelf plate (39). The plurality of shelf plates (39) are fixed by welding through an outer vertical fixing rod (42), an intermediate vertical fixing rod (43) and an inner vertical fixing rod (44). An annular array of the plurality of outer vertical fixing rods (42) passes through the outermost ring body, an annular array of the plurality of inner vertical fixing rods (44) passes through the innermost ring body, and an annular array of the plurality of intermediate vertical fixing rods (43) passes through the middle position of the shelf plates (39). The intermediate vertical fixing rods (43) and the outer vertical fixing rods (42) are staggered.

10. A deep ion nitriding process for gears with high load-bearing capacity according to claim 2, characterized in that: A nitrogen inlet pipe (6) is installed at the lower end of one side of the nitriding furnace body (1), and an exhaust gas exhaust pipe (32) and an air exhaust pipe (33) are installed on the nitriding furnace cover (30). The lower ends of the exhaust gas exhaust pipe (32) and the air exhaust pipe (33) extend into the nitriding furnace hearth (4).

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