Multi-temperature-zone continuous quenching and tempering integrated device for heat treatment of steel plate spring

Abstract

The invention relates to the technical field of metal material heat treatment, in particular to a multi-temperature-zone continuous quenching and tempering integrated device for steel plate spring heat treatment, which comprises a base plate and a multi-temperature-zone base station arranged on the base plate, and a quenching box and a tempering box are arranged on the base station side by side. A gantry type supporting frame is arranged on one side of the base plate, and a direction adjusting unit on the top of the gantry type supporting frame drives the transverse displacement frame and the clamping arm distance adjusting module installed on the transverse displacement frame to move in the plane. And two sets of clamping mechanical arms capable of independently lifting are hoisted at the bottom of the clamping arm distance adjusting module, and steerable clamping jaws are installed at the tail ends of the mechanical arms and used for clamping and transferring the steel plate springs. A conical guide quenching tank and a direct heating element are arranged in the quenching box; the tempering box is of an inner and outer barrel structure and is provided with a bottom heating flow guide and top forced circulation air system, and a uniform and controllable tempering environment is formed.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for metallic materials, specifically a multi-temperature zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs. Background Technology

[0002] As a key load-bearing and vibration-damping component in vehicle suspension systems, the mechanical properties and service life of leaf springs largely depend on the quality of the heat treatment process. A standard heat treatment process typically includes two key steps: quenching and tempering. Quenching aims to impart a high-strength martensitic structure to the material, while tempering is used to eliminate quenching stress, stabilize the structure, and endow the spring with excellent overall mechanical properties.

[0003] In existing technologies, the quenching and tempering processes of leaf springs are typically completed in two separate sets of equipment. This existing approach has a drawback: the discrete nature of the processes leads to poor production continuity and unstable quality control. Because the quenching and tempering equipment are separate, the workpiece undergoes multiple transfers and waiting periods between processes. This not only prolongs the production cycle and reduces efficiency, but more importantly, the time the workpiece is exposed to air after quenching is difficult to control precisely, easily leading to temperature fluctuations and surface oxidation. This affects the uniformity of the microstructure transformation during subsequent tempering, ultimately negatively impacting the consistency of the spring's hardness, elasticity, and fatigue life. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-temperature zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A multi-zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs, comprising: A substrate and a multi-temperature zone platform disposed on the substrate, wherein a quenching box and a tempering box are arranged side by side on the multi-temperature zone platform; A support frame is disposed on the substrate, and a support top frame is provided on the top of the support frame; The orientation adjustment unit is installed on the support top frame. The orientation adjustment unit includes a first rotating slide, a second rotating slide, and a transverse displacement frame installed between the two. The clamping arm spacing adjustment module is installed on the transverse displacement frame, and the bottom of the clamping arm spacing adjustment module is suspended by a first lifting frame and a second lifting frame. The first clamping arm and the second clamping arm are respectively connected to the clamping arm spacing adjustment module through the first lifting frame and the second lifting frame, and their bottoms form a clamping structure for clamping the steel leaf spring. The clamping arm spacing adjustment module is used to drive the first clamping arm and the second clamping arm to move synchronously towards or away from each other to adjust the clamping spacing; the orientation adjustment unit is used to drive the clamping arm spacing adjustment module together with the first clamping arm and the second clamping arm to move along the transverse displacement frame, and to drive the transverse displacement frame to move along the first operating slide and the second operating slide, so that the clamping structure can transfer the leaf spring between the quenching box, the tempering box and the turnover storage box set on the multi-temperature zone base.

[0006] As a further aspect of the present invention: the multi-temperature zone base includes a base body, an installation platform is provided on the base body, a first mounting seat and a second mounting seat are respectively installed on the installation platform, the quenching box is mounted on the first mounting seat, the tempering box is mounted on the second mounting seat, a first temporary storage box is provided on the side edge of the quenching box, and a second temporary storage box is provided on the side edge of the tempering box.

[0007] As a further aspect of the present invention: the quenching box includes a support frame and a processing box disposed on the support frame. The processing box is provided with an inner liner, and a quenching tank is installed inside the inner liner. The cavity of the quenching tank is a conical, concave guide section. The upper opening of the guide section is connected to the inlet of the inner liner. The side wall of the quenching tank is provided with a plurality of heating elements, and the bottom is connected to a drain section. The bottom of the drain section is provided with an auxiliary heater, and the side wall is connected to a drain channel.

[0008] As a further aspect of the present invention: the tempering box includes a bottom box and a tempering cylinder erected on the bottom box. The bottom of the tempering cylinder is installed inside the bottom box, and a cavity top cover is provided on the top. An openable and closable inlet is provided on the side wall. A circulating air cavity is provided on the top of the cavity top cover. A fan inlet is provided on one side of the circulating air cavity, and a fan outlet is provided on the opposite side.

[0009] As a further aspect of the present invention: an inner guide tube is coaxially arranged inside the tempering tube, an air duct box is arranged at the bottom of the tempering tube, an airflow confluence cavity is formed inside the air duct box, and the upper opening of the airflow confluence cavity communicates with the inner cavity of the inner guide tube.

[0010] As a further aspect of the present invention: the bottom of the air duct box is supported by a bottom support frame, the bottom support frame is provided with an upwardly extending support column, and the top of the support column extends into the airflow confluence and is equipped with a guide cone.

[0011] As a further aspect of the present invention: an electric heater is also provided on the bottom support frame, the electric heater is connected to a gas guide pipe, the gas guide pipe is connected to a protective gas source, and the electric heater is used to send the heated protective gas into the airflow confluence through the periphery of the guide cone.

[0012] As a further aspect of the present invention: both the first clamping arm and the second clamping arm include a clamping arm bracket, the top of the clamping arm bracket is provided with a ceiling frame, the ceiling frame is connected to the clamping arm spacing adjustment module through a displacement mounting head; a hydraulic drive cylinder is provided on the clamping arm bracket, the piston rod of the hydraulic drive cylinder extends downward and is connected to a clamping device through a rod end connector.

[0013] As a further aspect of the present invention: the clamping device includes a clamping base, a steering adjuster disposed on the clamping base, and a support rod mounted on the steering adjuster, wherein a gripper assembly is mounted at the end of the support rod.

[0014] As a further embodiment of the present invention: the gripper assembly includes a gripper base and swing bolts symmetrically arranged on both sides of the gripper base, each swing bolt having a gripper portion hinged to it, and a reset spring being provided between the gripper portion and the gripper base.

[0015] Compared with the prior art, the beneficial effects of the present invention are: The design integrates two independent heat treatment processes, quenching and tempering, into a single machine, connected in series by a multi-degree-of-freedom automated transfer system. This enables unmanned, continuous operation of leaf springs from heating and quenching to tempering. The transfer system combines a high-precision planar movement orientation adjustment unit with a clamping arm module that can flexibly adjust the clamping distance, driving two independently lifting and rotating clamping robotic arms to precisely grasp, adjust the posture of, and transfer springs of different specifications. The quenching chamber employs a conical guide structure and a built-in heater to ensure the workpiece is smoothly and uniformly immersed in the constant-temperature medium for rapid cooling. The tempering chamber, through its unique inner and outer cylinder design, constructs a vertically circulating forced convection hot air field, combined with a bottom flow equalization and protective gas system, achieving highly uniform and controllable temperature field and atmosphere within the furnace.

[0016] This invention significantly shortens production cycle time through process integration and automated production lines, reducing heat loss, oxidation, and deformation risks during workpiece turnover, and greatly improving production efficiency and heat treatment consistency. Secondly, adaptive clamping and precise posture control enhance the equipment's flexibility, enabling rapid adaptation to various product specifications. Furthermore, the specially optimized quenching and tempering chamber structures ensure uniformity of rapid cooling and uniform heat distribution during low-temperature tempering, effectively improving key performance indicators such as product hardness, metallographic stability, and fatigue life.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Furthermore, these drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments.

[0019] Figure 1 This is a schematic diagram of the overall structure of the multi-temperature zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the multi-temperature zone base provided in an embodiment of the present invention.

[0021] Figure 3 This is a cross-sectional structural diagram of the quenching box provided in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the tempering chamber provided in an embodiment of the present invention.

[0023] Figure 5 This is a cross-sectional structural diagram of the tempering tube provided in an embodiment of the present invention.

[0024] Figure 6 The diagram shows the structure of the first clamping arm and the second clamping arm provided in the embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of the gripper assembly provided in an embodiment of the present invention.

[0026] In the diagram: 1. Base plate; 11. Support frame; 12. Support top frame; 13. Orientation adjustment unit; 14. First operating slide; 15. Second operating slide; 16. Transmission frame; 17. Lateral displacement frame; 2. Multi-temperature zone base; 21. Base body; 22. Mounting platform; 23. First mounting seat; 24. Second mounting seat; 25. First temporary storage box; 26. Second temporary storage box; 31. First clamping arm; 32. Second clamping arm; 33. Arm bracket; 34. Hydraulic drive cylinder; 35. Ceiling frame; 36. Displacement mounting head; 37. Piston rod; 38. Rod end connector; 41. First lifting frame; 42. Second lifting frame; 5. Clamping arm spacing adjustment module; 6. Quenching box; 61. Support box frame; 62. Processing box; 63. Inner liner; 64. Guide section; 65. Quenching tank; 66. Heating element; 67. Drainage section; 68. Auxiliary heater; 69. Drainage channel; 7. Tempering box; 71. Bottom box; 72. Tempering tube; 73. Feed inlet; 74. Cavity top cover; 75. Circulating air chamber; 76. Fan inlet; 77. Fan outlet; 80. Bottom support frame; 81. Inner guide tube; 82. Air duct box; 83. Airflow junction; 84. Support column; 85. Guide cone; 86. Electric heater; 87. Air duct; 88. Protective air source; 9. Clamping mechanism; 91. Clamping base; 92. Steering adjuster; 93. Support rod; 94. Claw assembly; 95. Claw seat; 96. Swing bolt; 97. Claw part; 98. Reset spring. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, examples of which are illustrated in the drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or identical elements.

[0028] Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0030] Example 1, please refer to Figures 1 to 5This invention provides a multi-zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs, using a horizontally arranged base plate 1 as the mounting foundation. A multi-zone platform 2 is fixedly mounted in the middle of the upper surface of the base plate 1, forming a support platform for the two main heat treatment stations: quenching and tempering. Specifically, the multi-zone platform 2 includes a rectangular platform body 21, the upper surface of which forms a flat mounting platform 22. Two independent mounting seats are fixed side-by-side on the mounting platform 22: a first mounting seat 23 and a second mounting seat 24. A quenching box 6 is securely mounted on the first mounting seat 23 by a support structure at its bottom, while a tempering box 7 is mounted on the second mounting seat 24. A first temporary storage box 25 is installed on the side of the quenching box 6 (e.g., near the feeding direction), and a second temporary storage box 26 is installed on the side of the tempering box 7 for temporary placement and cushioning of the springs.

[0031] On the substrate 1, a portal frame-like support frame 11 is vertically erected on one side of the multi-temperature zone base 2. A horizontally extending support top frame 12 is fixedly connected to the top of the support frame 11, forming a gantry-like frame covering the space above the multi-temperature zone base 2. On the lower surface of the support top frame 12, an orientation adjustment unit 13 responsible for large-range movement is installed. This unit includes two parallel longitudinal guide rails (i.e., a first operating slide 14 and a second operating slide 15), and a lateral displacement frame 17 that can slide along the two longitudinal guide rails is installed laterally across them. A transmission frame 16 that drives the lateral displacement frame 17 to move longitudinally is provided on one side. On the lateral displacement frame 17, a clamping arm spacing adjustment module 5 that can slide along its length is installed. The bottom of the clamping arm spacing adjustment module 5 is connected to two independent lifting frames via a lifting structure: a first lifting frame 41 and a second lifting frame 42.

[0032] The bottom ends of the first lifting frame 41 and the second lifting frame 42 are rigidly connected to the first clamping arm 31 and the second clamping arm 32, respectively. The two clamping arms are symmetrically structured and each includes a vertical arm support 33. A ceiling frame 35 is fixed to the top of the arm support 33, and the ceiling frame 35 is connected to the upper clamping arm spacing adjustment module 5 through a displacement mounting head 36. A hydraulic drive cylinder 34 is installed on the front of the arm support 33. The piston rod 37 of the hydraulic drive cylinder 34 extends vertically downward, and a clamping device 9 is installed at the end of the piston rod 37 through a rod end connector 38. The clamping device 9 includes a clamping base 91 fixed to the rod end connector 38. A steering adjuster 92 is installed below the clamping base 91. A horizontally extending support rod 93 is connected to the output end of the steering adjuster 92, and a gripper assembly 94 for directly clamping a spring is installed at the end of the support rod 93. The gripper assembly 94 has a gripper base 95, and two swingable gripper portions 97 are hinged to both sides of the gripper base 95 by swing bolts 96. A reset spring 98 is provided between the gripper portions 97 and the gripper base 95 to provide a reset force.

[0033] The structure of the quenching box 6 is as follows: its exterior is a sturdy supporting frame 61, and its interior houses the processing box 62. The inner wall of the processing box 62 is equipped with a heat-resistant inner liner 63, within which a quenching tank 65 is placed. The cavity of the quenching tank 65 is designed as a conical, recessed guide section 64, with its upper opening aligned with the inlet at the top of the inner liner 63 for easy workpiece entry. Multiple sets of heating elements 66 are circumferentially embedded in the side walls of the quenching tank 65, and its bottom connects to a funnel-shaped drainage section 67. An auxiliary heater 68 is installed at the bottom of the drainage section 67, and a drainage channel 69 connecting to external pipelines is opened in the side wall. The tempering box 7 consists of a lower base 71 and an upper vertical tempering cylinder 72. The tempering cylinder 72 has an openable cavity cover 74 at the top and an openable / closable feed inlet 73 on the side. A circulating air chamber 75 is located above the top cover 74 of the cavity, with a fan inlet 76 on one side and a fan outlet 77 on the opposite side. An inner guide tube 81 is coaxially fitted inside the tempering tube 72, and a built-in air duct box 82 is connected to its bottom. An airflow confluence chamber 83 is formed inside the air duct box 82, and its upper part communicates with the inner cavity of the inner guide tube 81. The air duct box 82 is supported by a bottom support frame 80, with a support column 84 extending upward into the airflow confluence chamber 83 in the center of the bottom support frame 80, and a guide cone 85 installed on the top of the column. An electric heater 86 is also installed on the bottom support frame 80, and the electric heater 86 is connected to an external protective air source 88 through a gas duct 87.

[0034] During operation, the leaf spring to be processed is first placed in the first temporary storage box 25. The orientation adjustment unit 13 drives the lateral displacement frame 17 and the clamping arm spacing adjustment module 5 to move, positioning the first clamping arm 31 and the second clamping arm 32 above the first temporary storage box 25. Next, the clamping arm spacing adjustment module 5 adjusts the spacing between the two clamping arms to match the length of the spring. Then, the hydraulic drive cylinder 34 descends, and when the gripper assembly 94 contacts the spring, the gripper portion 97 is pressed and swings, firmly clamping both ends of the spring by the elastic force of the return spring 98. After the clamping is stable, the two clamping arms are raised synchronously, and the orientation adjustment unit 13 moves it directly above the quenching box 6. The clamping arms descend, vertically placing the spring into the guide section 64 of the quenching box 6 for heating and quenching. After completion, the clamping arms remove the spring and transfer it to the second temporary storage box 26 for brief draining or cooling. Subsequently, the clamping arm grips the spring again and positions it in front of the feed inlet 73 of the tempering chamber 7 via the orientation adjustment unit 13. The feed inlet 73 opens, and the clamping arm horizontally feeds the spring into the suspension or support position within the tempering cylinder 72, then withdraws, closing the feed inlet 73 for tempering. After tempering, the clamping arm can remove the finished spring, completing one continuous operation cycle.

[0035] This embodiment integrates discrete quenching, transfer, and tempering processes into a continuous production line through a highly integrated spatial layout and a multi-degree-of-freedom robotic arm system. The orientation adjustment unit 13 provides precise planar positioning capabilities along the X-axis (lateral) and Y-axis (longitudinal), while the clamping arm spacing adjustment module 5 provides adaptive adjustment capabilities along the Z-axis (spacing adjustment). Combined with the lifting and turning of the clamping mechanism 9, it enables the grasping, transfer, and placement of long strip steel leaf springs in any position within three-dimensional space. The conical guide section 64 of the quenching chamber 6 guides the springs accurately and smoothly into the quenching medium, ensuring uniform quenching. The tempering chamber 7 utilizes an internal guide tube 81 and airflow circulation design, along with a bottom electric heater 86 and a guide cone 85, to form a uniform and controllable forced convection hot air field within the tempering tube 72. Inert gas can be injected through the protective gas source 88 to prevent oxidation of the spring surface.

[0036] This embodiment achieves seamless integration and automated continuous production of quenching and tempering processes for leaf springs within the same equipment, significantly reducing workpiece handling time, waiting time, and manual operation between processes, and substantially improving production efficiency and heat treatment consistency. The combination of a gantry-type moving mechanism and adjustable-pitch clamping arms allows the device to flexibly adapt to springs of different lengths and specifications, offering strong versatility. The specialized structural design of the quenching and tempering chambers optimizes the rapid cooling (quenching) and slow heating (tempering) process environments, respectively, ensuring the final product's microstructure and mechanical properties.

[0037] Example 2, as Figure 6 and Figure 7 As shown, this embodiment optimizes the flexibility and control precision of the clamping and transfer system, especially the clamping mechanism 9, based on the overall structure of Embodiment 1. The layout and connection relationship of the base plate 1, multi-temperature zone base 2, support frame 11, support top frame 12, and orientation adjustment unit 13 are the same as in Embodiment 1.

[0038] The clamping arm spacing adjustment module 5 is also mounted on the transverse displacement frame 17, under which the first clamping arm 31 and the second clamping arm 32 are suspended. The improvement of this embodiment lies in the fact that the clamping mechanism 9 equipped with the first clamping arm 31 and the second clamping arm 32 has a more precise steering adjustment function. Specifically, the clamping base 91 is fixed to the rod end connector 38. A steering adjuster 92 is formed below the clamping base 91 via a high-precision bearing assembly or worm gear mechanism. This steering adjuster 92 is driven by a small servo motor, enabling the support rod 93, which is fixed to it, to rotate precisely at least 180 degrees in the horizontal plane. The gripper assembly 94 at the end of the support rod 93 has a structure similar to that of Embodiment 1, including a gripper seat 95, a swing pin 96, a gripper portion 97, and a return spring 98. Furthermore, a vision sensor or position sensor can be integrated on the arm support 33 to identify the workpiece position and orientation.

[0039] When the gripper arm moves above the first temporary storage box 25 to grasp the spring, the steering adjuster 92 can pre-drive the support rod 93 to rotate, so that the opening direction of the gripper assembly 94 is optimally matched with the placement direction of the spring, ensuring accurate gripping. After grasping the spring, the steering adjuster 92 can adjust the spring's posture as needed during the transfer process. For example, when removing the spring from the quenching box 6, the gripper can rotate to position the spring at the optimal drip angle. When sending the spring into the tempering box 7, the gripper arm is first precisely positioned outside the inlet 73. The steering adjuster 92 then rotates the support rod 93 and the gripped spring to a horizontal position. Then, the hydraulic drive cylinder 34 pushes the gripper arm horizontally into the inlet 73, precisely placing the spring on the bracket inside the tempering tube 72, rather than simply dropping it vertically. After placement, the gripper arm retracts horizontally, and the inlet 73 closes. Throughout the process, sensors provide real-time feedback to ensure the actions are performed correctly.

[0040] Preferably, the basic structure of the quenching box 6 and the tempering box 7 is consistent with that of Embodiment 1. However, in this embodiment, the feed inlet 73 of the tempering box 7 can be designed as a sealed door that can slide up and down or left and right, and its opening and closing action is linked to the movement of the clamping arm through the control system.

[0041] This embodiment compensates for the shortcomings of the orientation adjustment unit 13 and the clamping arm spacing adjustment module 5, which mainly provide planar and spacing movements, by introducing an active rotational degree of freedom (steering adjuster 92) to the clamping end. This allows the clamping tool to not only move into position but also adjust the workpiece to the most suitable angle before finally contacting or placing it. This mimics the "alignment" and "adjustment" actions in manual operation. Combined with sensor feedback, a closed-loop control system is formed, thereby realizing coarse and fine adjustments of the six degrees of freedom (X, Y, Z, spacing, rotation, pitch / tilt can be achieved through different heights of the dual grippers) of position and orientation of the long strip workpiece (leaf spring) in three-dimensional space, greatly improving the adaptability and reliability of automated operation.

[0042] Example 3, as Figure 5 As shown, based on Embodiment 1 or Embodiment 2, this embodiment further elaborates on the internal hot air circulation and heating system of the tempering box 7.

[0043] The bottom section 71 of the tempering chamber 7 is a closed cabinet. The air duct box 82 is suspended and fixed to the center of the bottom section 71 by connecting parts around it, and its bottom is fixed to the bottom plate of the bottom section 71 by several height-adjustable support columns 84. The upper part of the air duct box 82 is cylindrical and is sealed to the bottom flange of the tempering chamber 72. Its internal cavity forms the lower airflow confluence 83. In the center of the air duct box 82, a sturdy support column 84 extends vertically upward from the bottom plate of the bottom section 71, and its top extends to the upper middle part of the airflow confluence 83, where a guide cone 85 is fixedly installed. The guide cone 85 is a cone or frustum with a smaller top and a larger bottom, and its side forms an annular airflow channel with the inner wall of the air duct box 82.

[0044] Inside the base chamber 71, around the exterior of the air duct box 82, at least one electric heater 86 (such as an electric heating tube or finned heater) is installed. The outlet of the electric heater 86 is connected to the air inlet on the lower side wall of the air duct box 82 via an insulated air guide pipe 87. The other end of the air guide pipe 87 is connected to a protective gas source 88 (such as a nitrogen or argon storage tank) via a three-way valve or other components. A circulating air chamber 75 is fixed on the top cover 74 inside the tempering tube 72, and a centrifugal fan is installed inside it. The fan inlet 76 is located on the bottom side of the circulating air chamber 75 and leads directly to the top space of the tempering tube 72. The fan outlet 77 is connected to a hot air pipe that extends downward and leads to the upper end of the annular gap between the tempering tube 72 and the inner guide tube 81.

[0045] At the start of the tempering process, the inlet 73 is sealed. The control system activates the electric heater 86 and the protective gas source 88. The proportionally mixed heating gas (or the pure protective gas is heated) enters the lower part of the air duct box 82 tangentially through the gas guide pipe 87. The airflow spirals upward in the annular channel, flows evenly across the conical surface of the guide cone 85, is further rectified and diffused, and then smoothly enters the internal cavity of the upper inner guide cylinder 81. At the same time, the fan in the circulating air chamber 75 starts working, drawing gas from the central area at the top of the tempering cylinder 72 to create a negative pressure. The drawn gas is pressurized through the fan outlet 77 and sent into the annular gap between the tempering cylinder 72 and the inner guide cylinder 81. Guided by the annular gap, the hot air flows downward along the outer wall of the inner guide cylinder 81. After reaching the bottom, it turns back from the lower opening of the inner guide cylinder 81 and flows upward into the inner cavity of the inner guide cylinder 81, where it is drawn back by the fan at the top, thus forming a complete, closed vertical circulating airflow. The leaf spring suspended inside the inner guide tube 81 is surrounded by this uniform, high-speed circulating hot air, achieving rapid and uniform heating and heat preservation.

[0046] The tempering chamber design in this embodiment significantly improves heat treatment quality. The vertically circulating, uniform hot air field ensures that all springs suspended within the furnace, as well as different parts of the springs themselves, receive nearly identical heat input, resulting in extremely uniform microstructure and hardness, and excellent tempering stability. Forced convection heating is much faster than simple radiation heating, shortening the tempering process cycle and improving equipment utilization. The sealed circulation system and the introduction of protective gas effectively isolate oxygen, preventing oxidation and decarburization of the spring surface at tempering temperatures, thus maintaining surface smoothness and fatigue strength.

[0047] Example 4, as Figure 3 As shown, this embodiment focuses on describing the optimized structure of the quenching box 6 and its collaborative working method with the overall device.

[0048] The supporting frame 61 of the quenching chamber 6 is a robust welded steel frame. The processing chamber 62 has a double-layer structure, with high-performance insulation material filling the space between the outer shell and the inner liner 63. The inner liner 63 is made of an alloy material that is resistant to high temperatures and corrosion from the quenching liquid. The quenching tank 65, as an independent and replaceable container, sits on the supporting flange inside the inner liner 63. Its core feature is the guide section 64, which consists of a large-diameter conical section at the top and a cylindrical or gradually changing section at the bottom, with a smooth inner wall to guide the workpiece to fall without obstruction. The heating elements 66 are multiple sets of independently temperature-controlled tubular electric heaters, which are inserted directly into specially designed sealed sleeves on the side walls of the quenching tank 65 in a circumferentially distributed manner to achieve direct radial heating of the quenching medium (such as oil or polymer solution).

[0049] The draining zone 67 is an inverted conical collecting hopper located directly below the quenching tank 65, with its top connected to the bottom of the quenching tank 65 through an opening with a filter screen. The auxiliary heater 68 is a strip or plate-shaped electric heater, tightly attached to the lower outer wall of the draining zone 67. The draining channel 69 is connected to the lowest point of the side wall of the draining zone 67 and is equipped with an electric ball valve, leading to an external heat exchange system or waste liquid treatment system. Furthermore, an automatically opening and closing heat-insulating cover (not shown in the figure) can be installed on the top of the quenching box 6, which is closed when no workpiece is placed inside to reduce heat loss and medium evaporation.

[0050] Before the quenching process begins, the quenching tank 65 is filled with quenching medium. The heating element 66 heats the medium according to the process settings and maintains it at a predetermined temperature (such as the austenitizing temperature). When the steel leaf spring heated to the critical temperature is moved by the clamping arm to directly above the quenching tank 6, the heat preservation cover is opened. The clamping arm vertically and quickly lowers the hot spring into the guide section 64. Under the action of gravity, the spring is rapidly immersed in the medium along the smooth conical surface, generating intense boiling heat transfer and completing the martensitic transformation. After the workpiece is held in the medium for a certain period of time, it is lifted out of the liquid surface by the clamping arm at a uniform speed. At this time, a large amount of the attached medium flows back into the tank. After the workpiece is transferred, the heat preservation cover is closed. When it is necessary to replace or filter the medium, the valve of the drain channel 69 is opened, and the medium flows out through the drain section 67. The auxiliary heater 68 attached to the wall can prevent the residual medium from becoming viscous due to cooling during the discharge process, ensuring complete drainage. During normal production, the auxiliary heater 68 can also serve as an auxiliary heat source, working in conjunction with the side wall heating element 66 to maintain a uniform temperature inside the tank.

[0051] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0052] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-temperature zone continuous quenching and tempering integrated device for heat treatment of steel leaf springs, comprising a base plate (1) and a multi-temperature zone platform (2) disposed thereon, wherein a quenching box (6) and a tempering box (7) are arranged side by side on the multi-temperature zone platform (2); characterized in that: It also includes an orientation adjustment unit (13) disposed above the substrate (1) and a clamping arm spacing adjustment module (5) driven to move by the orientation adjustment unit (13). The clamping arm spacing adjustment module (5) is equipped with a first clamping arm (31) and a second clamping arm (32) that can move synchronously towards or away from each other, for clamping the steel leaf spring. The quenching box (6) is provided with a quenching groove (65) inside. The groove cavity of the quenching groove (65) is a conical concave guide section (64), and a heating element (66) is provided on its side wall. The bottom is connected to a drain section (67). The tempering box (7) includes a vertical tempering tube (72) with an inner guide tube (81) coaxially arranged inside. The bottom of the tempering tube (72) is provided with a duct box (82) with an airflow chamber (83) formed inside. The upper opening of the airflow chamber (83) communicates with the inner cavity of the inner guide tube (81). The bottom of the duct box (82) is provided with a guide cone (85) and an electric heater (86) for heating and introducing protective gas. The orientation adjustment unit (13) drives the first clamping arm (31) and the second clamping arm (32) to transfer the steel leaf spring between the guide section (64) of the quenching box (6), the inner guide cylinder (81) of the tempering box (7) and the temporary storage box set next to both, so as to realize continuous heat treatment.

2. The multi-temperature zone continuous quenching and tempering integrated device according to claim 1, characterized in that, An auxiliary heater (68) is provided at the bottom of the drainage section (67).

3. The multi-temperature zone continuous quenching and tempering integrated device according to claim 1, characterized in that, The top of the tempering tube (72) is provided with a cavity top cover (74), and the top of the cavity top cover (74) is provided with a circulating air cavity (75). One side of the circulating air cavity (75) is provided with a fan inlet (76), and the other side is provided with a fan outlet (77).

4. The multi-temperature zone continuous quenching and tempering integrated device according to claim 1, characterized in that, Both the first clamping arm (31) and the second clamping arm (32) include a clamping arm support (33), and a hydraulic drive cylinder (34) is provided on the clamping arm support (33). The piston rod (37) of the hydraulic drive cylinder (34) extends downward and is connected to a clamping device (9).

5. The multi-temperature zone continuous quenching and tempering integrated device according to claim 4, characterized in that, The clamping device (9) includes a clamping base (91), a steering adjuster (92) disposed on the clamping base (91), and a support rod (93) mounted on the steering adjuster (92), with a gripper assembly (94) installed at the end of the support rod (93).

6. The multi-temperature zone continuous quenching and tempering integrated device according to claim 5, characterized in that, The gripper assembly (94) includes a gripper seat (95) and swing bolts (96) symmetrically arranged on both sides of the gripper seat (95). Each swing bolt (96) is hinged with a gripper portion (97), and a reset spring (98) is provided between the gripper portion (97) and the gripper seat (95).

7. The multi-temperature zone continuous quenching and tempering integrated device according to claim 1, characterized in that, A first temporary storage box (25) is provided on the side edge of the quenching box (6) on the multi-temperature zone base (2), and a second temporary storage box (26) is provided on the side edge of the tempering box (7).

8. The multi-temperature zone continuous quenching and tempering integrated device according to claim 1, characterized in that, The orientation adjustment unit (13) includes a first operating slide (14), a second operating slide (15), and a transverse displacement frame (17) mounted between the two. The clamping arm spacing adjustment module (5) is installed on the transverse displacement frame (17).

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