A deep carburizing and quenching assembly of a gear hardness improving device

Abstract

The utility model provides a kind of deep carburizing quenching assembly of gear hardness promotion device belongs to gear processing technical field, the deep carburizing quenching assembly of gear hardness promotion device includes carburizing cavity, quenching immersion cylinder and temperature regulation ring, quenching immersion cylinder is set in the lower of carburizing cavity, the bottom of carburizing cavity is equipped with through passage, quenching immersion cylinder is connected with the lower end of through passage by support seat, temperature regulation ring is set around the outer wall of through passage, temperature regulation ring is connected with the bottom outer surface of carburizing cavity by fixed bolt, the inner circle wall surface of temperature regulation ring and the outer circumferential surface between through passage form annular gap, the radial width of annular gap is gradually distributed along axial direction, annular gap width at upper end is greater than annular gap width at lower end;The utility model can solve the technical problems that the hardness distribution of gear after quenching is uneven and geometric deformation exceeds tolerance range.

Description

Technical Field

[0001] This utility model belongs to the field of gear processing technology, and specifically relates to a deep carburizing and quenching component of a gear hardness enhancement device. Background Technology

[0002] Gears, as core components of mechanical transmission systems, are widely used in automotive gearboxes, engineering machinery reducers, wind power generation gearboxes, and ship propulsion devices. The matching performance of their surface hardness and core toughness directly determines their load-bearing capacity and service life. To improve the surface hardness and wear resistance of gears, deep carburizing and quenching has become an indispensable heat treatment process in gear manufacturing. This process involves infiltrating carbon atoms into the gear surface at high temperatures to form a high-carbon carburized layer, followed by rapid quenching to achieve a high-hardness martensitic structure. Existing gear carburizing and quenching devices typically employ a separate layout of carburizing furnace and quenching tank. After carburizing and holding in the carburizing furnace, the gear needs to be transferred to the quenching tank for quenching and cooling via a robotic arm or conveyor. During the transfer, the gear is exposed to ambient temperature, causing a rapid drop in surface temperature. When the gear enters the quenching medium, a significant temperature difference has formed between the surface and the core. At this point, the rapid cooling of the surface by the quenching medium further intensifies the temperature gradient, generating enormous thermal and structural stresses at the interface between the carburized layer and the substrate.

[0003] To address this issue, existing technologies primarily employ methods such as extending the conveying time between the carburizing furnace outlet and the quenching tank inlet to achieve slow cooling, or adding a pre-cooling process before quenching to allow the gears to be initially cooled in a milder medium. However, extending the conveying time reduces production efficiency and makes it difficult to precisely control the temperature drop curve. Adding a pre-cooling process complicates the equipment structure and increases investment costs and floor space. In practical applications, these methods all suffer from limitations such as insufficient control precision, large equipment investment, and complex operation, making it difficult to meet the dual requirements of modern gear manufacturing for both processing quality stability and production efficiency. Utility Model Content

[0004] In view of this, the present invention provides a deep carburizing and quenching component for a gear hardness enhancement device. This component addresses the problem in existing gear carburizing and quenching devices where the gear lacks an effective temperature transition control mechanism during the transfer from the high-temperature carburizing chamber to the low-temperature quenching medium. This results in the gear surface experiencing drastic temperature gradient changes within a very short time, causing a rapid concentration of thermal stress at the interface between the gear surface and the core. This leads to micro-cracks or delamination at the interface between the carburized layer and the substrate, severely affecting the gear's fatigue strength and service life. Simultaneously, it solves the problem that the existing device's structural design fails to fully consider the differentiated requirements of temperature field distribution at different processing stages and lacks precise control over the temperature gradient in the transfer channel area. This results in inconsistent temperature drop rates across different parts of the gear surface as it passes through the transfer channel, leading to uneven hardness distribution and geometric deformation exceeding tolerances after quenching.

[0005] This utility model is implemented as follows:

[0006] This utility model provides a deep carburizing and quenching component for a gear hardness enhancement device, including a carburizing cavity, a quenching immersion cylinder, and a temperature control ring. The quenching immersion cylinder is located below the carburizing cavity. A through channel is formed at the bottom of the carburizing cavity. The cross-sectional area of ​​the through channel is smaller than the cross-sectional area of ​​the inner cavity of the carburizing cavity. The quenching immersion cylinder is connected to the lower end of the through channel via a support base. The temperature control ring is arranged around the outer wall of the through channel and is connected to the bottom outer surface of the carburizing cavity via fixing bolts. An annular gap is formed between the inner wall of the temperature control ring and the outer circumferential surface of the through channel. The radial width of the annular gap is gradually distributed along the axial direction, and the width of the annular gap at the upper end is greater than the width of the annular gap at the lower end.

[0007] The technical effects of the deep carburizing and quenching component of the gear hardness enhancement device provided by this utility model are as follows: By forming an annular gap with a radially varying width along the axial direction between the inner wall of the temperature control ring and the outer circumferential surface of the through channel, the flow velocity and pressure of the gas or heat in the annular gap are varied. The wider annular gap at the upper end reduces the airflow velocity and increases the pressure, while the narrower annular gap at the lower end increases the airflow velocity and decreases the pressure. This creates a differentiated temperature control effect at different heights in the through channel, ensuring that the gear undergoes a gradual temperature transition during the transfer from the carburizing cavity to the quenching immersion cylinder. This avoids thermal stress concentration and microcracks on the gear surface caused by sudden temperature changes, thereby improving the quality stability of the carburizing and quenching process.

[0008] Based on the above technical solution, the deep carburizing and quenching component of the gear hardness enhancement device of this utility model can be further improved as follows:

[0009] The top of the carburizing chamber is provided with a conical feed inlet with a cone angle of 45° to 60°. The bottom diameter of the conical feed inlet is equal to the diameter of the inner cavity of the carburizing chamber.

[0010] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By setting a conical feed inlet with a cone angle of 45°~60° at the top of the carburizing chamber, the gear is guided by the conical inner wall when entering the carburizing chamber. As the gear slides in along the conical surface, it gradually decelerates and automatically adjusts its posture to the vertical direction, avoiding the gear from entering the carburizing chamber at a large tilt angle or high speed and causing violent collision with the inner wall of the chamber. This reduces the risk of scratches or impact damage to the gear surface. At the same time, the structure in which the bottom diameter of the conical feed inlet is equal to the inner diameter of the carburizing chamber ensures that the gear smoothly transitions into the processing area, improving the reliability of the feeding process and the integrity of the gear surface.

[0011] Furthermore, multiple heat dissipation grooves are evenly distributed circumferentially on the wall of the quenching immersion cylinder. The heat dissipation grooves have a longitudinal strip structure and the depth of the heat dissipation grooves is one-third to one-half of the thickness of the wall of the quenching immersion cylinder.

[0012] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By uniformly distributing multiple longitudinal strip-shaped heat dissipation grooves with a depth of one-third to one-half of the wall thickness along the circumference of the quenching immersion cylinder wall, the contact area between the outer surface of the quenching immersion cylinder and the surrounding environment is increased, promoting the heat of the quenching medium inside the cylinder to dissipate outward through the cylinder wall, accelerating the temperature recovery rate of the quenching medium, and avoiding the weakening of the quenching effect due to the continuous temperature rise of the quenching medium caused by continuous use. At the same time, the longitudinal strip-shaped structure of the heat dissipation grooves will not damage the overall strength of the quenching immersion cylinder, ensuring that the cylinder maintains structural stability under the action of internal liquid pressure and thermal stress, extending the service life of the quenching immersion cylinder and maintaining the consistency of the quenching treatment.

[0013] Furthermore, the support base has an annular boss structure, and the outer diameter of the support base is larger than the lower outer diameter of the through channel. The upper surface of the support base is welded to the lower end face of the through channel.

[0014] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by designing the support base as an annular boss structure with an outer diameter larger than the outer diameter of the lower end of the through channel, and welding the upper surface of the support base to the lower end face of the through channel, the support base forms a bearing platform extending outward in the radial direction. This bearing platform distributes the weight of the quenching immersion cylinder and the weight of the internal quenching medium to a larger contact area, reduces the stress concentration at the weld joint, and avoids weld cracking or loosening of the connection due to long-term bearing of gravity and thermal cycling. At the same time, the annular boss structure provides a stable support reference surface for subsequent maintenance or replacement of the quenching immersion cylinder, improving the connection reliability and maintenance convenience of the components.

[0015] Furthermore, the inner wall of the temperature control ring has a stepped structure, which forms a first step surface, a second step surface, and a third step surface from top to bottom, and the steps are connected by a vertical transition surface.

[0016] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By designing the inner wall of the temperature control ring into a stepped structure with a first step surface, a second step surface, and a third step surface sequentially formed from top to bottom, the annular gap forms a clear width segment at different axial heights. The vertical transition surface between each step surface causes local disturbance and eddy current effect when the airflow or heat flows through different steps, which enhances the uniformity of heat transfer and avoids local overheating or undercooling areas during temperature control. At the same time, the stepped structure facilitates processing and dimensional control, ensuring that the positional accuracy and surface quality of each step surface meet the design requirements, and improving the temperature control ring's ability to accurately control the temperature field around the through channel and the stability of the heat treatment process.

[0017] Furthermore, the outer circumferential surface of the through channel is provided with multiple protruding ridges along the axial direction. The protruding ridges extend along the axial direction of the through channel, and the cross-section of the protruding ridges is triangular or trapezoidal.

[0018] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By setting multiple protruding ridges with triangular or trapezoidal cross-sections along the axial direction on the outer circumferential surface of the through channel, the roughness and surface area of ​​the outer surface of the through channel are increased. This causes the gas or heat flowing through the annular gap to undergo microscopic-scale diversion and convergence when it encounters the protruding ridges, thereby enhancing the heat exchange efficiency between the airflow and the surface of the through channel and promoting the rapid adjustment of the temperature of the through channel wall. At the same time, the presence of the protruding ridges causes the airflow to form a spiral flow trajectory during axial flow, prolonging the residence time of the airflow in the annular gap, improving the sufficiency of heat transfer, ensuring that the temperature distribution of the outer surface of the gear is more uniform when it passes through the through channel, and reducing the risk of quenching deformation caused by uneven temperature.

[0019] Furthermore, the bottom of the quenching immersion cylinder is sealed, and the side wall and bottom of the quenching immersion cylinder are connected by an arc transition surface, the radius of which is one-tenth to one-fifth of the inner diameter of the quenching immersion cylinder.

[0020] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by designing the quenching immersion cylinder as a structure with a closed bottom and the side wall connected to the bottom by an arc transition surface with a radius of one-tenth to one-fifth of the cylinder's inner diameter, the sharp edges of the cylinder bottom are eliminated. When the gear descends into the quenching immersion cylinder and approaches the bottom, it is smoothly guided by the arc transition surface, avoiding the collision between the gear tooth root and the right-angle edge of the cylinder bottom, which would cause stress concentration points or local damage. At the same time, the arc transition surface creates a smooth flow path for the quenching medium at the bottom of the cylinder, reducing liquid stagnation areas and bubble accumulation, improving the uniformity of contact between the quenching medium and the gear surface, and ensuring that the gear as a whole obtains a consistent quenching cooling effect and surface hardness distribution.

[0021] Furthermore, the carburizing chamber is made of heat-resistant alloy steel, the quenching immersion cylinder is made of stainless steel, and the temperature control ring is made of copper alloy.

[0022] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by selecting heat-resistant alloy steel to make the carburizing chamber, stainless steel to make the quenching immersion cylinder, and copper alloy to make the temperature control ring, the material properties of each component are matched with their working environment and functional requirements. Heat-resistant alloy steel has excellent high-temperature strength and oxidation resistance, making it suitable for withstanding the high-temperature environment during carburizing. Stainless steel has good corrosion resistance, making it suitable for long-term contact with the quenching medium. Copper alloy has high thermal conductivity, making it suitable for achieving rapid temperature transfer and control. The reasonable combination of different materials avoids premature failure or functional degradation of components due to insufficient material properties, extends the service life of the entire deep carburizing and quenching assembly, reduces maintenance frequency and replacement costs, and improves the economy and stability of the production process.

[0023] Furthermore, the sidewall thickness of the carburizing chamber is greater than the wall thickness of the quenching immersion cylinder, and the ratio of the sidewall thickness of the carburizing chamber to the wall thickness of the quenching immersion cylinder is 2:1 to 4:1.

[0024] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by designing the sidewall thickness of the carburizing chamber to be greater than the wall thickness of the quenching immersion cylinder, and controlling the thickness ratio of the two within the range of 2:1 to 4:1, the carburizing chamber has a stronger load-bearing capacity and heat capacity to cope with the high temperature and high pressure environment during the carburizing process. The quenching immersion cylinder adopts a relatively thinner cylinder wall, which can meet the structural strength requirements and improve the thermal conductivity of the cylinder wall, accelerate the absorption of gear heat by the quenching medium inside the cylinder, and achieve rapid quenching and cooling. At the same time, the reasonable thickness ratio enables the entire component to achieve an optimal balance between weight, strength and thermal performance, avoiding material waste and excessive thermal inertia due to excessive thickness, or insufficient strength and deformation risk due to excessive thinness, thereby improving the overall performance and reliability of the component.

[0025] Furthermore, there are 6 to 12 fixing bolts evenly distributed along the circumference of the temperature control ring. The fixing bolts pass through the bolt holes of the temperature control ring and are screwed into the threaded holes on the outer surface of the bottom of the carburizing chamber. The diameter of the bolt holes is larger than the diameter of the screw of the fixing bolt.

[0026] The beneficial effects of adopting the above-mentioned improved scheme are as follows: By evenly distributing 6 to 12 fixing bolts along the circumference of the temperature control ring, and screwing the bolts through bolt holes with a diameter larger than that of the screw into the threaded holes on the outer surface of the bottom of the carburizing chamber, reliable fixation between the temperature control ring and the carburizing chamber is achieved. The evenly distributed fixing bolts ensure that the connection force is evenly distributed around the circumference of the temperature control ring, avoiding local stress concentration that could lead to deformation of the temperature control ring or displacement of the fixed position. At the same time, the design of the bolt hole diameter being larger than that of the screw provides adjustment space for dimensional changes of the temperature control ring due to thermal expansion, preventing the temperature control ring from cracking or loosening at the connection with the carburizing chamber due to thermal stress limitation in high-temperature environments. This improves the thermal stability and long-term reliability of the connection structure, ensuring that the temperature control ring always maintains the correct installation position and functional state during use.

[0027] Compared with existing technologies, the beneficial effects of the deep carburizing and quenching component of the gear hardness enhancement device provided by this utility model are as follows: By setting a temperature control ring and forming an annular gap with a radially varying width along the axial direction between its inner ring wall and the outer circumferential surface of the through channel, a gradual temperature control mechanism for the gear during the transfer process is established in principle. The gradual distribution of the annular gap width causes continuous changes in flow velocity and pressure when the airflow passes through different height positions, forming a segmented temperature buffer zone, effectively avoiding sudden changes in the gear surface temperature, extending the originally concentrated instantaneous thermal stress release process into a continuous and gradual stress relaxation process, significantly reducing the stress concentration at the interface between the carburized layer and the matrix, improving the interface bonding strength and the overall crack resistance of the gear. At the same time, by setting convex ridges on the outer surface of the through channel and the quenching immersion cylinder wall... By incorporating multiple structural optimization measures, such as heat dissipation grooves and a stepped temperature control ring inner wall, a three-dimensional temperature field control network is established. This enables precise control of the temperature distribution at key locations along the gear transfer path, ensuring that all parts of the gear surface undergo similar temperature processes. This results in a uniform carburized layer depth and surface hardness, reduces quenching deformation, and improves the gear's dimensional accuracy retention. Furthermore, by optimizing the geometry and connection methods of various components, such as the guiding effect of the conical feed inlet, the buffer protection of the arc transition surface, and the rational configuration of thickness ratios, the structural reliability and operational stability of the device are comprehensively improved. This reduces the risk of surface damage to the gears during processing, extends the device's service life, and provides reliable technical support for high-quality deep carburizing and quenching treatment of gears, meeting the increasingly demanding requirements of modern mechanical transmission systems for gear performance. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A three-dimensional structural schematic diagram of a deep carburizing and quenching component for a gear hardening device;

[0030] Figure 2 This is a schematic diagram of the cross-section of the temperature control loop and the through-channel segment;

[0031] Figure 3 A front view of a deep carburizing and quenching component of a gear hardening device;

[0032] The attached diagram lists the components represented by each number as follows:

[0033] 10. Carburizing chamber; 11. Quenching immersion cylinder; 12. Temperature control ring; 13. Through channel; 14. Support base; 15. Annular gap; 16. Conical feed inlet; 17. Heat dissipation groove; 18. First step surface; 19. Second step surface; 20. Third step surface; 21. Raised ridge; 22. Arc transition surface; 23. Fixing bolt. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0035] like Figure 1-3 The image shows a first embodiment of a deep carburizing and quenching component for a gear hardness enhancement device provided by this utility model. In this embodiment, it includes a carburizing chamber 10, a quenching immersion cylinder 11, and a temperature control ring 12. The quenching immersion cylinder is located below the carburizing chamber. A through channel 13 is provided at the bottom of the carburizing chamber. The cross-sectional area of ​​the through channel is smaller than the cross-sectional area of ​​the inner cavity of the carburizing chamber. The quenching immersion cylinder is connected to the lower end of the through channel through a support base 14. The temperature control ring is arranged around the outer wall of the through channel and is connected to the bottom outer surface of the carburizing chamber through a fixing bolt 23. An annular gap 15 is formed between the inner wall of the temperature control ring and the outer circumferential surface of the through channel. The radial width of the annular gap is gradually distributed along the axial direction, and the width of the annular gap at the upper end is greater than the width of the annular gap at the lower end.

[0036] In the above technical solution, the top of the carburizing chamber is provided with a conical feed port 16, the cone angle of the conical feed port is 45°~60°, and the bottom diameter of the conical feed port is equal to the diameter of the inner cavity of the carburizing chamber.

[0037] Furthermore, in the above technical solution, multiple heat dissipation grooves 17 are evenly distributed circumferentially on the wall of the quenching immersion cylinder. The heat dissipation grooves have a longitudinal strip structure, and the depth of the heat dissipation grooves is one-third to one-half of the thickness of the wall of the quenching immersion cylinder.

[0038] Furthermore, in the above technical solution, the support base has an annular boss structure, the outer diameter of the support base is larger than the lower outer diameter of the through channel, and the upper surface of the support base is welded to the lower end face of the through channel.

[0039] Furthermore, in the above technical solution, the inner wall of the temperature control ring has a stepped structure, which forms a first step surface 18, a second step surface 19 and a third step surface 20 from top to bottom, and the step surfaces are connected by a vertical transition surface.

[0040] Furthermore, in the above technical solution, the outer circumferential surface of the through channel is provided with multiple protruding ribs 21 along the axial direction. The protruding ribs extend along the axial direction of the through channel, and the cross-section of the protruding ribs is triangular or trapezoidal.

[0041] Furthermore, in the above technical solution, the bottom of the quenching immersion cylinder is closed, and the side wall and bottom of the quenching immersion cylinder are connected by an arc transition surface 22, the radius of which is one-tenth to one-fifth of the inner diameter of the quenching immersion cylinder.

[0042] Furthermore, in the above technical solution, the carburizing chamber is made of heat-resistant alloy steel, the quenching immersion cylinder is made of stainless steel, and the temperature control ring is made of copper alloy.

[0043] Furthermore, in the above technical solution, the sidewall thickness of the carburizing cavity is greater than the wall thickness of the quenching immersion cylinder, and the ratio of the sidewall thickness of the carburizing cavity to the wall thickness of the quenching immersion cylinder is 2:1 to 4:1.

[0044] Furthermore, in the above technical solution, 6 to 12 fixing bolts are evenly distributed along the circumference of the temperature control ring. The fixing bolts pass through the bolt holes of the temperature control ring and are screwed into the threaded holes on the outer surface of the bottom of the carburizing chamber. The diameter of the bolt holes is larger than the diameter of the screw of the fixing bolt.

[0045] The method of using this utility model is as follows: First, the gear to be processed is fed into the carburizing chamber through a conical inlet. Guided by the inner wall of the conical shape, the gear descends smoothly into the processing area of ​​the carburizing chamber. Then, a carburizing atmosphere is introduced into the carburizing chamber, and the chamber is heated to the carburizing temperature for heat preservation treatment. After carburizing is completed, heating is stopped, and the atmosphere is adjusted. At this time, the gear slowly descends from the through-channel at the bottom of the carburizing chamber under its own weight or with the help of an auxiliary pushing device. During the descent, the outer surface of the gear maintains an appropriate gap with the inner wall of the through-channel to avoid frictional damage. Simultaneously, the airflow in the annular gap begins to gradually cool the gear surface. The airflow source is a gas with controllable temperature and flow rate introduced to the upper end of the annular gap through an external gas supply system. The gas flows from top to bottom through the annular gap, generating different flow rates in gap sections of different widths. The operation involves adjusting the air supply temperature and flow rate based on process parameters such as the gear's material, size, and carburized layer depth. This controls the gear's descent speed and surface temperature drop curve within the through-channel. Once the gear has completely passed through the through-channel and entered the quenching immersion cylinder, it is immersed in quenching oil or quenching liquid pre-stored in the cylinder for final rapid cooling. The temperature of the quenching medium is maintained within the required range by an external cooling system. Heat dissipation grooves on the cylinder wall assist in temperature control of the quenching medium. After the gear has remained in the quenching medium for a specified time, it is removed for subsequent tempering and cleaning. Throughout the operation, the temperature control ring is securely connected to the bottom of the carburizing chamber via fixing bolts, eliminating the need for frequent adjustments or maintenance. It can be disassembled simply by loosening the fixing bolts when replacement or repair is required, making the operation simple, safe, and reliable.

[0046] The following is a specific embodiment of this utility model: The deep carburizing and quenching component in this embodiment is used to process medium-sized gears with a module of 3 to 5. The carburizing cavity is made of Cr25Ni20 heat-resistant alloy steel. The inner diameter of the cavity is 350 mm, the height is 600 mm, and the side wall thickness is 15 mm. The cone angle of the top conical feed inlet is designed to be 52°. The upper opening diameter of the feed inlet is 280 mm, and the bottom diameter is the same as the inner diameter of the cavity, which is 350 mm. The height of the conical feed inlet is 120 mm. The through channel opened at the bottom of the cavity is a cylindrical structure with an inner diameter of 180 mm. The outer diameter is 210mm, and the channel length is 240mm. Eight raised ribs are evenly distributed axially along the outer circumference of the channel. Each rib has an isosceles triangular cross-section with a base width of 8mm and a height of 5mm. These ribs are continuously distributed along the entire length of the channel. The quenching immersion cylinder is made of 316L stainless steel, with an inner diameter of 200mm, a wall thickness of 6mm, and a height of 450mm. Twelve heat dissipation grooves are evenly distributed circumferentially along the cylinder wall. These grooves are longitudinal rectangular, 10mm wide, 3mm deep, and 400mm long. The bottom of the quenching immersion cylinder is a closed flat plate structure, with a connection between the sidewalls and the bottom. The connection is made via a 25mm radius arc surface. The support base is made of Q345 low-alloy steel and has an annular boss structure with an outer diameter of 260mm. Its inner diameter matches the lower outer diameter of the through-channel at 210mm. The support base is 20mm thick. The upper surface of the support base is argon-arc welded to the lower end face of the through-channel, with a weld width of 8mm. The temperature control ring is made of H62 brass and has an annular structure with an outer diameter of 320mm. The inner diameter is designed in a stepped shape; the first step of the upper section has an inner diameter of 230mm and an axial length of 80mm; the second step of the middle section has an inner diameter of 220mm and an axial length of 80mm. The length is 80mm, the inner diameter of the third step surface of the lower section is 215mm, and the axial length is 80mm. Each step surface is connected by a vertical transition surface with a height of 5mm. The overall height of the temperature control ring is 240mm, the same as the length of the through channel. The temperature control ring is connected to the bottom outer surface of the carburizing chamber by eight M10 fixing bolts. The bolt hole diameter is 12mm, and the bolt center circle diameter is 280mm. The bolts are evenly distributed circumferentially, with adjacent bolts spaced at 45° intervals. During use, nitrogen or inert gas at a temperature of 600~700℃ is introduced into the upper end of the annular gap, with the gas flow rate controlled at 15~25m³ / h. 3The gear descends at a speed controlled at 8-12 mm / s in the through-channel. The gear surface temperature gradually decreases from the carburizing temperature of 850℃ to 650-700℃ upon entering the quenching medium. The quenching immersion cylinder contains N32 quenching oil, maintained at 60-80℃. The gear is cooled to below 200℃ in the quenching oil before being removed. Throughout the process, the carburized layer depth reaches 1.2-1.5 mm, the surface hardness reaches 58-62 HRC, and no cracks or delamination appear on the gear surface. The gear tooth profile and tooth direction accuracy remain within grade 6, and the deformation is controlled within 0.08 mm. This embodiment utilizes a gradual design of the annular gap to maintain a suitable surface temperature decrease rate of 18-25℃ per second during the transfer process. Within the specified range, thermal stress concentration caused by sudden temperature drops is avoided. The convex ridge structure causes the airflow to form a spiral flow trajectory on the outer surface of the through channel, extending the contact time between the airflow and the wall by about 30%, significantly improving the adequacy of heat exchange. The stepped inner wall of the temperature control ring creates flow resistance differences at different heights, resulting in airflow velocities of 2.5~3.2 m / s in the upper section, 3.8~4.5 m / s in the middle section, and 5~6 m / s in the lower section, achieving segmented increasing cooling intensity. The heat dissipation groove of the quenching immersion cylinder increases the outer surface area of ​​the cylinder wall by about 25%, reduces the quenching oil temperature rise rate by about 40%, and maintains the temperature stability of the quenching medium. The arc transition surface reduces the impact force on the gear when it enters the bottom of the quenching immersion cylinder by about 60%, avoiding stress concentration points at the tooth root.

[0047] The following is another specific embodiment 2 of this utility model: Based on embodiment 1, the cross-sectional shape of the protruding ridges on the outer circumferential surface of the through-channel is changed from an isosceles triangle to an isosceles trapezoid. The upper base width of the trapezoid is 4mm, the lower base width is 8mm, and the height is 5mm. The number of protruding ridges is increased to 12, with adjacent ridges evenly distributed at 30-degree intervals in the circumferential direction. Simultaneously, several small ventilation holes with a diameter of 3mm are opened circumferentially on each step surface of the temperature control ring. Sixteen ventilation holes are opened on the first step surface, twelve on the second step surface, and eight on the third step surface. The small vents allow some gas to flow radially from the annular gap into the through-channel and directly contact the gear surface, enhancing the local cooling effect. The upper bottom plane of the trapezoidal convex ridge forms a more stable contact surface with the airflow, reducing the degree of airflow turbulence and making temperature control more stable. The segmented decreasing design of the vents allows more gas to flow into the upper section to provide initial cooling, while the amount of gas flowing into the lower section is reduced to avoid over-cooling. This embodiment is suitable for precision gear processing with higher requirements for temperature uniformity. The temperature difference between different parts of the gear surface is controlled within 15°C, the standard deviation of hardness distribution after quenching is reduced by about 25%, and the fatigue life of the gear is increased by about 18%.

[0048] The following is another specific embodiment 3 of this utility model: This embodiment is based on embodiment 1, in which multiple annular guide protrusions are arranged axially on the inner wall of the quenching immersion cylinder. The annular guide protrusions are annular structures protruding into the cylinder body, with a height of 4mm, a width of 8mm, and a semi-circular cross-section. A total of 5 annular guide protrusions are arranged from top to bottom, and the axial distance between adjacent protrusions is 80mm. The annular guide protrusions guide the quenching medium along the flow path of the gear surface in segments when the gear descends in the quenching immersion cylinder. The quenching medium forms a local circulation flow in the annular space between each protrusion, increasing the relative flow rate and contact time between the quenching medium and the gear surface, improving the uniformity and efficiency of quenching cooling. At the same time, the thickness of the support base is increased to 30mm, and multiple heat dissipation ribs are radially opened on the lower surface of the support base. The heat dissipation ribs are radially extending plate-like structures with a thickness of 30mm. With a diameter of 5mm and a height of 25mm, the support has 8 heat dissipation fins. These fins increase the contact area between the support and the surrounding air, accelerating heat dissipation from the support and the lower part of the through-channel, preventing temperature control inaccuracies due to heat accumulation. This embodiment improves the quenching cooling rate by approximately 15% and reduces the residual austenite content after gear quenching by approximately 20% through optimization of the internal flow field of the quenching immersion cylinder and enhancement of the heat dissipation capacity of the support area. It also improves surface hardness stability. Simultaneously, the heat dissipation fin structure of the support reduces the temperature at the lower end of the through-channel by approximately 30-50°C, resulting in a more reasonable temperature connection with the upper end of the quenching immersion cylinder. This further optimizes the temperature curve during gear transfer, reducing the impact of temperature fluctuations on processing quality. This embodiment is particularly suitable for processing high-carbon alloy steel gears with strict hardenability requirements, achieving a deeper hardened layer and higher surface hardness uniformity.

[0049] Specifically, the principle of this invention is as follows: Through a specially designed temperature control ring and a gradually changing annular gap structure, a controllable temperature transition zone is established during the gear's transfer from the carburizing cavity to the quenching immersion cylinder. When the gear descends from the carburizing cavity into the through-channel, the annular gap around the through-channel forms a dynamic temperature buffer layer. The wider annular gap at the upper end reduces the airflow velocity and increases the static pressure, allowing the airflow to remain in this area for a longer time and exchange heat fully with the outer surface of the through-channel. This maintains the temperature of the upper section of the through-channel at a relatively high level, providing a gentle initial cooling environment for the high-temperature gear just entering from the carburizing cavity. As the gear continues to descend, the width of the annular gap in the middle and lower sections gradually decreases, the airflow velocity gradually increases, and the static pressure decreases. The cooling effect of the airflow on the through-channel gradually strengthens, allowing the gear to experience a continuous and gradual temperature decrease, avoiding abrupt temperature changes. The convex ridge structure on the outer surface of the through-channel further enhances this gradual effect, causing the airflow to generate localized temperature variations. Disturbances and secondary flows increase the contact time and area between the airflow and the wall, improving heat exchange efficiency and making the temperature distribution more uniform. The temperature control ring is made of copper alloy with excellent thermal conductivity, which can quickly respond to temperature changes in the annular gap and finely adjust the temperature field around the through channel through heat conduction. The stepped inner wall structure forms differentiated flow resistance and heat exchange characteristics at different axial positions, realizing segmented precise temperature control. When the gear reaches the quenching immersion cylinder through the through channel, its surface temperature has undergone a sufficient gradual decrease, and the temperature difference between the surface and the core is controlled within a reasonable range. At this time, it enters the quenching medium for final quenching and cooling, and the peak value of thermal stress is greatly reduced. The stress concentration phenomenon at the interface between the carburized layer and the matrix is ​​effectively alleviated. The heat dissipation grooves on the wall of the quenching immersion cylinder ensure the stability of the quenching medium temperature, and the arc transition surface at the bottom avoids collision damage between the gear and the cylinder. The entire component achieves precise temperature field control and high-quality gear processing through the synergistic effect of structural design.

Claims

1. A deep carburizing and quenching component for a gear hardness enhancement device, comprising a carburizing chamber, a quenching immersion cylinder, and a temperature control ring, wherein the quenching immersion cylinder is disposed below the carburizing chamber, a through channel is formed at the bottom of the carburizing chamber, the cross-sectional area of ​​the through channel is smaller than the cross-sectional area of ​​the inner cavity of the carburizing chamber, the quenching immersion cylinder is connected to the lower end of the through channel via a support base, the temperature control ring is arranged around the outer wall of the through channel, and the temperature control ring is connected to the bottom outer surface of the carburizing chamber via fixing bolts, characterized in that... An annular gap is formed between the inner wall of the temperature control ring and the outer circumferential surface of the through channel. The radial width of the annular gap is gradually distributed along the axial direction, and the width of the annular gap at the upper end is greater than that at the lower end.

2. The deep carburizing and quenching component of the gear hardness enhancement device according to claim 1, characterized in that, The top of the carburizing chamber is provided with a conical feed inlet with a cone angle of 45°~60°. The bottom diameter of the conical feed inlet is equal to the diameter of the inner cavity of the carburizing chamber.

3. The deep carburizing and quenching component of the gear hardness enhancement device according to claim 2, characterized in that, Multiple heat dissipation grooves are evenly distributed circumferentially on the wall of the quenching immersion cylinder. The heat dissipation grooves have a longitudinal strip structure and the depth of the heat dissipation grooves is one-third to one-half of the thickness of the wall of the quenching immersion cylinder.

4. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 3, characterized in that, The support base has an annular boss structure. The outer diameter of the support base is larger than the lower outer diameter of the through channel. The upper surface of the support base is welded to the lower end face of the through channel.

5. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 4, characterized in that, The inner wall of the temperature control ring has a stepped structure, which consists of a first step surface, a second step surface, and a third step surface from top to bottom, and the steps are connected by vertical transition surfaces.

6. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 5, characterized in that, The outer circumferential surface of the through channel is provided with multiple protruding ridges along the axial direction. The protruding ridges extend along the axial direction of the through channel, and the cross-section of the protruding ridges is triangular or trapezoidal.

7. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 6, characterized in that, The bottom of the quenching immersion cylinder is closed, and the side wall and bottom of the quenching immersion cylinder are connected by a circular arc transition surface. The radius of the circular arc transition surface is one-tenth to one-fifth of the inner diameter of the quenching immersion cylinder.

8. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 7, characterized in that, The carburizing chamber is made of heat-resistant alloy steel, the quenching immersion cylinder is made of stainless steel, and the temperature control ring is made of copper alloy.

9. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 8, characterized in that, The sidewall thickness of the carburizing chamber is greater than the wall thickness of the quenching immersion cylinder, and the ratio of the sidewall thickness of the carburizing chamber to the wall thickness of the quenching immersion cylinder is 2:1 to 4:

1.

10. The deep carburizing and quenching component of a gear hardness enhancement device according to claim 9, characterized in that, There are 6 to 12 fixing bolts evenly distributed along the circumference of the temperature control ring. The fixing bolts pass through the bolt holes of the temperature control ring and are screwed into the threaded holes on the outer surface of the bottom of the carburizing chamber. The diameter of the bolt holes is larger than the diameter of the bolt screw.

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