Universal joint cross shaft carburizing and quenching device based on gradient temperature control

Abstract

The application provides a gradient temperature control based universal joint cross shaft carburizing and quenching device, and relates to the field of universal joint cross shafts, which comprises a base, supporting feet, an outer cover supporting column, an arc-shaped outer cover and a fixed platform. Four supporting feet are fixedly arranged at the four sides of the bottom of the base to achieve stable supporting effect, and the fixed platform is fixedly arranged at the top end of the base. The four shaft necks are non-synchronously cooled by adopting four shaft neck independent heating and gradient temperature control quenching strategy, and the internal stress accumulated due to structural rigidity constraint in traditional overall quenching is effectively released. The closed heating plate design can tightly embrace the shaft neck of the workpiece, form a uniform and stable heating field, and combine the workpiece rotation function driven by the servo motor to make the shaft neck of the workpiece evenly heated, so that the carburizing atmosphere flows fully, thereby ensuring the consistency of the carburizing layer depth and carbon concentration gradient.

Description

Technical Field

[0001] This invention relates to the field of universal joint cross shaft technology, specifically to a universal joint cross shaft carburizing and quenching device based on gradient temperature control. Background Technology

[0002] Universal joint cross shafts are core components in automotive transmission systems, construction machinery, and other fields. Their service conditions are typically extremely harsh, requiring them to withstand enormous alternating torque, bending stress, and severe wear. Therefore, extremely high requirements are placed on the surface hardness, wear resistance, fatigue strength, and core toughness of their journal sections. Carburizing and quenching is the most widely used chemical heat treatment process for improving the surface mechanical properties of such parts. It aims to obtain a hard, wear-resistant martensitic structure on the journal surface through the diffusion of carbon and subsequent quenching.

[0003] The universal joint cross shaft has a unique geometry, with four journals symmetrically arranged in a spatial cross shape. During the overall heating and cooling process, unavoidable micro-temperature differences exist among the journals, leading to asynchronous thermal expansion and contraction. More importantly, during overall quenching, all four journals are immersed in the quenching medium almost simultaneously, and the intense cooling process generates enormous structural and thermal stresses. Due to the symmetry and rigidity of the cross shaft structure, these stresses cannot be freely released, easily causing plastic deformations such as twisting, bending, or out-of-tolerance relative journal positions in the workpiece. Such deformations are difficult to completely correct through subsequent finishing processes, severely affecting product yield, assembly accuracy, and the dynamic balance performance of the transmission assembly.

[0004] Therefore, an innovative heat treatment device is needed that can perform precise, independent, and efficient heat treatment of the four journals of the universal joint cross shaft, taking into account its special structure. Summary of the Invention

[0005] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a gradient temperature-controlled carburizing and quenching device for universal joint cross shafts. Targeting the unique structure of the universal joint cross shaft, it enables precise, independent, and efficient heat treatment of its four journals, fundamentally overcoming the bottleneck problems of deformation, uneven performance, and low efficiency caused by overall processing, thus solving the problems mentioned in the background art.

[0006] Technical solution To achieve the above objectives, the present invention is implemented through the following technical solution: a universal joint cross shaft carburizing and quenching device based on gradient temperature control, comprising a base, support feet, outer cover support columns, an arc-shaped outer cover, and a fixed platform. The four support feet are fixedly disposed on the four sides of the bottom of the base to provide stable support. The fixed platform is fixedly disposed on the top of the base. The arc-shaped outer cover is disposed above the fixed platform. The arc-shaped outer cover is arc-shaped and has an opening at the top. A plurality of outer cover support columns are fixedly disposed below the outer end face of the arc-shaped outer cover. The outer cover support columns are arranged in a circular array and are fixedly connected to the top of the base. The fixed platform is rotatably equipped with a drive shaft at its top, and a workpiece tray is mounted on the top of the drive shaft. The upper end of the workpiece tray is used to place a universal joint cross shaft. Lower heating plates are fixed on the four sides of the top of the workpiece tray. The lower heating plates are arranged in a circular array. An upper heating plate that can move up and down is provided above the lower heating plates. The upper heating plate and the lower heating plate are provided with heater mounting slots with openings facing each other. Resistance heaters are installed in the heater mounting slots on the upper and lower sides. The resistance heaters on both sides cooperate to realize the heating process. Two vertical enriched gas inlet risers are fixedly installed on one side of the top of the base. The enriched gas inlet risers on both sides are symmetrically arranged. An enriched gas delivery pipe is connected to one end face of the enriched gas inlet riser. One end of the enriched gas delivery pipe passes through the arc-shaped outer cover and is connected to a gas nozzle.

[0007] Preferably, two linear drive rails are fixedly provided on both sides inside the arc-shaped outer cover. The linear drive rails are installed and connected to the fixed platform. The linear drive rails on both sides are symmetrically arranged. A telescopic door connecting rod is provided inside the linear drive rail. A movable door is provided on one side of the arc-shaped outer cover opening. The movable door is arc-shaped. Both sides of the movable door are installed and connected to one end of the door connecting rod.

[0008] Preferably, the top of the movable cover door is provided with a crossbeam of a cross frame, and two upward-opening cover plate rotating grooves are provided on both sides of the top of the crossbeam. The cover plate rotating grooves on both sides are symmetrically arranged. A cover plate rotating rod is rotatably provided in the cover plate rotating groove. An upper cover plate is fixedly provided at the top of the cover plate rotating rod, and a handle is fixed on one side of the outer end face of the upper cover plate.

[0009] Preferably, a drive shaft is rotatably provided at the center of the fixed platform. The top end of the drive shaft is installed and connected to the bottom of the workpiece tray. The other end of the drive shaft extends downward and passes through the base. A servo motor is fixedly provided below the base, and the workpiece tray is poweredly connected to the servo motor.

[0010] Preferably, two hydraulic lifters are fixedly installed on both sides of the lower heating plate on each side. The hydraulic lifters are installed and connected to the top of the workpiece tray. The hydraulic lifters on both sides are symmetrically arranged. Each hydraulic lifter is equipped with a lifting rod that can be raised and lowered. The top of the lifting rod is installed and connected to both sides of the bottom of the upper heating plate.

[0011] Preferably, two symmetrically positioned upper electrical connectors are fixedly provided on both sides of the bottom of the upper heating plate, and two lower electrical connectors are respectively provided on the top of the workpiece tray and directly below the upper electrical connectors on both sides. When the lower electrical connectors come into contact with the upper electrical connectors, they can form an electrical connection.

[0012] Preferably, a temperature sensor is installed on one side of the lower heating plate, and a central controller is installed at the bottom of the workpiece tray and directly below the lower heating plate. The temperature sensor is connected to the central controller via data, and the central controller is connected to the control terminal via signal.

[0013] Preferably, the workpiece tray has an upward-opening workpiece positioning groove at its center, and the workpiece positioning groove is configured to fit the shape of the universal joint cross shaft.

[0014] Preferably, pressure rod supports are fixedly provided at the four corners of the top of the workpiece tray. The pressure rod supports are arranged in a circular array. Each pressure rod support has an outward-opening pressure rod groove. A workpiece pressure rod that can be flipped is installed in the pressure rod groove. Beneficial effects

[0015] This invention provides a carburizing and quenching device for universal joint cross shafts based on gradient temperature control. It has the following beneficial effects: This invention achieves asynchronous cooling of the four journals by employing an independent heating and gradient temperature control quenching strategy for the four journals. This effectively releases the internal stress accumulated due to the rigid constraints of the structure in traditional integral quenching, and significantly reduces plastic deformation problems such as workpiece twisting, bending, and journal position deviation.

[0016] This invention employs a closed heating plate design, which tightly surrounds the workpiece journal to form a uniform and stable heating field. Combined with the workpiece rotation function driven by a servo motor, it ensures that each journal of the workpiece is heated uniformly and that the carburizing atmosphere flows sufficiently, thereby ensuring the consistency of the carburized layer depth and carbon concentration gradient.

[0017] This invention uses a linear drive guide rail to automatically control the opening and closing of the movable cover door, combined with a manually flipped upper cover design, which ensures both the airtightness of the carburizing chamber and facilitates the loading and unloading of workpieces. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 This is a front view of the external structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the present invention; Figure 4 This is a top view of the external structure of the present invention; Figure 5 For the present invention Figure 4 A cross-sectional view along the AA direction; Figure 6 This is a front view of the external structure of the present invention; Figure 7 For the present invention Figure 6 Cross-sectional view along the BB direction; Figure 8 For the present invention Figure 1 Enlarged structural schematic diagram of the pressure bar component in the workpiece; Figure 9 For the present invention Figure 2 Enlarged structural view of the upper and middle heating plate components.

[0019] In the diagram: 101. Base; 102. Support leg; 103. Outer cover support column; 104. Arc-shaped outer cover; 105. Enriched gas inlet riser; 106. Fixed platform; 107. Enriched gas delivery pipe; 108. Linear drive guide rail; 109. Upper heating plate; 110. Workpiece pressure bar; 111. Cover plate rotating groove; 112. Cover plate rotating rod; 113. Upper cover plate; 114. Crossbeam; 115. Movable cover door; 116. Cover door connecting rod; 117. 118. Power connector; 119. Gas nozzle; 120. Central controller; 121. Resistance heater; 122. Lifting rod; 123. Hydraulic lifter; 124. Workpiece positioning slot; 125. Temperature sensor; 126. Handle; 127. Workpiece tray; 128. Power connector; 129. Servo motor; 130. Drive shaft; 131. Pressure rod rotating slot; 132. Pressure rod support; 133. Heater mounting slot; 144. Lower heating plate. Detailed Implementation

[0020] This invention provides a carburizing and quenching device for a universal joint cross shaft based on gradient temperature control, such as... Figure 1-9 As shown, it includes a base 101, support feet 102, outer cover support columns 103, arc-shaped outer cover 104, and fixed platform 106. Four support feet 102 are fixedly installed on the four sides of the bottom of the base 101 to provide stable support. The fixed platform 106 is fixedly installed on the top of the base 101. The arc-shaped outer cover 104 is installed above the fixed platform 106. The arc-shaped outer cover 104 is arc-shaped and has an opening at the top. Several outer cover support columns 103 are fixedly installed below the outer end face of the arc-shaped outer cover 104. The outer cover support columns 103 are arranged in a circular array and are fixedly connected to the top of the base 101. A drive shaft 129 is rotatably mounted on the top of the fixed platform 106. A workpiece tray 126 is mounted on the top of the drive shaft 129. The upper part of the workpiece tray 126 is used to place the universal joint cross shaft. Lower heating plates 133 are fixed on the four sides of the top of the workpiece tray 126. The positions of the lower heating plates 133 are arranged in a circular array. An upper heating plate 109 that can move up and down is provided above the lower heating plate 133. The upper heating plate 109 and the lower heating plate 133 are provided with heater mounting slots 132 with openings facing each other. Resistance heaters 120 are installed in the heater mounting slots 132 on both the upper and lower sides. The resistance heaters 120 on both sides cooperate to realize the heating process. Two vertical enriched gas inlet risers 105 are fixedly installed on one side of the top of the base 101. The enriched gas inlet risers 105 on both sides are symmetrically arranged. One end face of the enriched gas inlet riser 105 is connected to an enriched gas delivery pipe 107. One end of the enriched gas delivery pipe 107 passes through the arc-shaped outer cover 104 and is connected to a gas nozzle 118.

[0021] It should be further explained that the enriched gas inlet riser 105 is connected to an independent enriched gas pipeline, and the carburizing process is achieved through the enriched gas delivery pipe 107 and the gas nozzle 118.

[0022] Furthermore, two linear drive rails 108 are fixedly installed on both sides inside the arc-shaped outer cover 104. The linear drive rails 108 are installed and connected to the fixed platform 106. The linear drive rails 108 on both sides are symmetrically arranged. A telescopic door connecting rod 116 is provided inside the linear drive rail 108. A movable door 115 is provided on one side of the arc-shaped outer cover 104. The movable door 115 is arc-shaped. Both sides of the movable door 115 are installed and connected to one end of the door connecting rod 116.

[0023] It is worth further explaining that when the linear drive guide rail 108 is started, it can drive the cover rod 116 to extend and retract, and then drive the movable cover 115 to extend and retract through the installation connection. When the cover rod 116 is fully retracted and translated to the limit position, the movable cover 115 coincides with the arc-shaped outer cover 104 to form a semi-circular arc-shaped barrier cover. At this time, both the movable cover 115 and the arc-shaped outer cover 104 are tightly attached to the top of the fixed platform 106.

[0024] Furthermore, the top of the movable cover door 115 is provided with a crossbeam 114 of a cross frame. On both sides of the top of the crossbeam 114, there are two upward-opening cover plate rotation grooves 111. The cover plate rotation grooves 111 on both sides are symmetrically arranged. A cover plate rotating rod 112 is rotatably installed in the cover plate rotation groove 111. An upper cover plate 113 is fixedly installed at the top of the cover plate rotating rod 112. A handle 125 is fixed on one side of the outer end face of the upper cover plate 113.

[0025] It should be further explained that when the arc-shaped outer cover 104 coincides with the movable door 115, the upper cover 113 is rotated by holding the handle 125. At this time, the upper cover 113 is rotated with the cover plate rotating rod 112 as support, so that the upper cover 113 can cover the upper opening of the arc-shaped outer cover 104, thereby sealing the barrier formed by the movable door 115 and the arc-shaped outer cover 104, forming a closed carburizing process space.

[0026] Furthermore, a drive shaft 129 is rotatably provided at the center of the fixed platform 106. The top end of the drive shaft 129 is installed and connected to the bottom of the workpiece tray 126. The other end of the drive shaft 129 extends downward and passes through the base 101. A servo motor 128 is fixedly provided below the base 101. The workpiece tray 126 is poweredly connected to the servo motor 128.

[0027] It is worth noting that the servo motor 128 can perform precise, intermittent, or continuous rotation.

[0028] Furthermore, two hydraulic lifters 122 are fixedly installed on both sides of the lower heating plate 133 on each side. The hydraulic lifters 122 are installed and connected to the top of the workpiece tray 126. The hydraulic lifters 122 on both sides are symmetrically arranged. The hydraulic lifters 122 are equipped with lifting rods 121 that can be lifted and moved. The top of the lifting rods 121 is installed and connected to the bottom sides of the upper heating plate 109.

[0029] Furthermore, two symmetrically positioned upper power connectors 117 are fixedly provided on both sides of the bottom of the upper heating plate 109, and two lower power connectors 127 are respectively provided on the top of the workpiece tray 126 and directly below the upper power connectors 117 on both sides. When the lower power connectors 127 contact the upper power connectors 117, they can form an electrical connection.

[0030] Furthermore, a temperature sensor 124 is installed on one side of the lower heating plate 133, and a central controller 119 is installed at the bottom of the workpiece tray 126 and directly below the lower heating plate 133. The temperature sensor 124 is connected to the central controller 119 for data transmission, and the central controller 119 is connected to the control terminal for signal transmission.

[0031] It should be further explained that the power source built into the central controller 119 is electrically connected to the lower power connector 127. When the hydraulic lift 122 is started and drives the lifting rod 121 to descend to the limit position, the upper heating plate 109 and the surface of the upper cover plate 113 are attached to form a ring-shaped heater. At this time, the upper power connector 117 and the lower power connector 127 are electrically connected. The resistance heater 120 in the upper heating plate 109 and the lower heating plate 133 is controlled to start, which can heat the journal of the inserted universal joint cross shaft, and the temperature sensor 124 detects the temperature of the journal of the inserted universal joint cross shaft.

[0032] Furthermore, the workpiece tray 126 has an upward-opening workpiece positioning groove 123 at its center, and the workpiece positioning groove 123 is configured to fit the shape of the universal joint cross shaft.

[0033] Furthermore, pressure rod supports 131 are fixedly provided at the four corners of the top of the workpiece tray 126. The pressure rod supports 131 are arranged in a circular array. The pressure rod supports 131 are provided with pressure rod rotating grooves 130 with outward openings. A workpiece pressure rod 110 that can be flipped is installed in the pressure rod rotating grooves 130.

[0034] It should be further explained that a limiter is installed in the pressure rod support 131. When the universal joint cross shaft to be processed is placed into the workpiece positioning groove 123, the operator manually rotates the four sides of the workpiece pressure rod 110 and uses the limiter to stabilize the workpiece pressure rod 110 to a specific angle. The rotated workpiece pressure rod 110 then locks and limits the top of the universal joint cross shaft.

[0035] The usage method of this solution is as follows: S1. The operator places the universal joint cross shaft workpiece to be processed into the workpiece positioning groove 123 on the workpiece tray 126. Since the workpiece positioning groove 123 matches the geometric shape of the universal joint cross shaft, the initial positioning and support of the workpiece can be achieved. The workpiece pressure rods 110 set at the four corners are manually flipped so that they rotate around the pressure rod rotation groove 130 to the top of the workpiece, and are locked at a specific angle by the limiter in the pressure rod support 131, thereby reliably pressing the upper end of the workpiece to prevent the workpiece from shifting or vibrating during subsequent rotation or heat treatment.

[0036] S2. After the workpiece is fixed, start the linear drive guide rail 108, drive the door connecting rod 116 to extend, push the movable door 115 to move along the arc trajectory, so that it closes with the arc outer cover 104, together forming a semi-circular arc sealed cavity. The operator rotates the upper cover plate 113 by the handle 125, causing it to rotate around the cover plate rotating rod 112 and cover the opening above the arc-shaped outer cover 104, thereby forming a completely closed carburizing treatment chamber, providing the necessary atmosphere isolation and thermal stability for this process stage.

[0037] S3. Subsequently, enrichment gas, such as propane or natural gas, or other carburizing media, is introduced through enrichment gas inlet riser 105 and transported to gas nozzle 118 through enrichment gas delivery pipe 107. It is injected into the sealed cavity in a uniform spray manner to gradually replace the air in the cavity and form a carburizing atmosphere with a certain carbon potential. Subsequently, the central controller 119 controls the hydraulic lift 122 to move, pushing the lifting rod 121 down, which in turn moves the upper heating plate 109 downward until it closes with the lower heating plate 133, forming a heating cavity that surrounds the workpiece journal. Subsequently, the power connector 117 and the power connector 127 make contact and conduct, and the resistance heater 120 begins to heat up, heating the workpiece journal. The temperature sensor 124 monitors the temperature of the heating area in real time and feeds the data back to the central controller 119, realizing precise control and adjustment of the carburizing temperature.

[0038] S4. Subsequently, the servo motor 128 can drive the drive shaft 129 and the workpiece tray 126 to rotate slowly, intermittently or continuously, to promote the flow of the carburizing atmosphere and the uniformity of the carbon potential distribution, and to ensure the consistency of the carburizing layer depth and carbon concentration gradient.

[0039] S5. After carburizing is completed, the central controller 119 controls the resistance heaters 120 of each upper heating plate 109 and lower heating plate 133 to perform an independent, gradient power-off cooling procedure according to the preset process curve. Specifically, asynchronous cooling of the journals can be achieved by time-sharing power cut-off or power gradient adjustment of the four journal heating units, thereby effectively alleviating the problem of internal stress concentration caused by the rigid constraint of the cross structure. In addition, depending on the actual process requirements, the heating power of a certain journal can be maintained appropriately in the early stage of quenching to delay its cooling process, further control the sequence of microstructure transformation, and suppress deformation.

[0040] S6. After quenching, open the movable cover door 115 and the upper cover plate 113, take out the workpiece, and carry out subsequent cleaning, tempering and other processes. The universal joint cross shaft treated by this device has a highly uniform carburized layer on its surface, and its hardness and wear resistance are significantly improved. At the same time, due to the application of gradient temperature control and time-sharing quenching strategies, the deformation of the workpiece is effectively controlled, and the relative position accuracy of the journal is significantly improved, making it suitable for transmission system applications with high dynamic balance requirements.

[0041] S7. The central controller 119 of this device can be connected to the upper-level control terminal, such as an industrial computer or PLC system, to realize remote setting, real-time monitoring and data recording of process parameters. It has a high degree of automation and process repeatability and is suitable for large-scale production scenarios.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A carburizing and quenching device for a universal joint cross shaft based on gradient temperature control, comprising a base (101), support feet (102), an outer cover support column (103), an arc-shaped outer cover (104), and a fixed platform (106), characterized in that: The four support legs (102) are fixedly installed on the four sides of the bottom of the base (101) to provide stable support. The fixed platform (106) is fixedly installed on the top of the base (101). The arc-shaped outer cover (104) is installed above the fixed platform (106). The arc-shaped outer cover (104) is arc-shaped and has an opening at the top. Several outer cover support columns (103) are fixedly installed below the outer end face of the arc-shaped outer cover (104). The outer cover support columns (103) are arranged in a circular array. The outer cover support columns (103) are fixedly connected to the top of the base (101). The fixed platform (106) is rotatably provided with a drive shaft (129) at the top. A workpiece tray (126) is installed at the top of the drive shaft (129). The upper end of the workpiece tray (126) is used to place a universal joint cross shaft. A lower heating plate (133) is fixed on the four sides of the top of the workpiece tray (126). The lower heating plates (133) are arranged in a circular array. An upper heating plate (109) is provided above the lower heating plate (133). The upper heating plate (109) and the lower heating plate (133) are provided with heater mounting slots (132) with opposite openings. Resistance heaters (120) are installed in the heater mounting slots (132) on the upper and lower sides. The resistance heaters (120) on both sides cooperate to realize the heating process. Two vertical enriched gas inlet risers (105) are fixedly installed on one side of the top of the base (101). The enriched gas inlet risers (105) on both sides are symmetrically arranged. One end face of the enriched gas inlet riser (105) is connected to an enriched gas delivery pipe (107). One end of the enriched gas delivery pipe (107) passes through the arc-shaped outer cover (104) and is connected to a gas nozzle (118).

2. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: Two linear drive rails (108) are fixedly provided on both sides inside the arc-shaped outer cover (104). The linear drive rails (108) are installed and connected to the fixed platform (106). The linear drive rails (108) on both sides are symmetrically arranged. A door connecting rod (116) is provided inside the linear drive rails (108). A movable door (115) is provided on one side of the arc-shaped outer cover (104). The movable door (115) is arc-shaped. Both sides of the movable door (115) are installed and connected to one end of the door connecting rod (116).

3. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 2, characterized in that: The top of the movable cover (115) is provided with a crossbeam (114), and the top of the crossbeam (114) is provided with two upward-opening cover plate rotating grooves (111) on both sides. The cover plate rotating grooves (111) on both sides are symmetrically arranged. A cover plate rotating rod (112) is rotatably provided in the cover plate rotating groove (111). An upper cover plate (113) is fixedly provided at the top of the cover plate rotating rod (112), and a handle (125) is fixed on one side of the outer end face of the upper cover plate (113).

4. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: A drive shaft (129) is rotatably provided at the center of the fixed platform (106). The top end of the drive shaft (129) is installed and connected to the bottom of the workpiece tray (126). The other end of the drive shaft (129) extends downward and passes through the base (101). A servo motor (128) is fixedly provided below the base (101). The workpiece tray (126) is poweredly connected to the servo motor (128).

5. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: Two hydraulic lifters (122) are fixedly installed on both sides of the lower heating plate (133) on each side. The hydraulic lifters (122) are installed and connected to the top of the workpiece tray (126). The hydraulic lifters (122) on both sides are symmetrically arranged. The hydraulic lifters (122) are provided with lifting rods (121). The top of the lifting rods (121) is installed and connected to the bottom sides of the upper heating plate (109).

6. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: Two symmetrical upper power connectors (117) are fixedly provided on both sides of the bottom of the upper heating plate (109). Two lower power connectors (127) are respectively provided on the top of the workpiece tray (126) and directly below the upper power connectors (117) on both sides. When the lower power connectors (127) come into contact with the upper power connectors (117), they can form an electrical connection.

7. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: A temperature sensor (124) is installed on one side of the lower heating plate (133), and a central controller (119) is installed at the bottom of the workpiece tray (126) and directly below the lower heating plate (133). The temperature sensor (124) is connected to the central controller (119) via data, and the central controller (119) is connected to the control terminal via signal.

8. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: The workpiece tray (126) has an upward-opening workpiece positioning groove (123) at its center, and the workpiece positioning groove (123) is configured to fit the shape of the universal joint cross shaft.

9. The universal joint cross shaft carburizing and quenching device based on gradient temperature control according to claim 1, characterized in that: The workpiece tray (126) is fixed with pressure rod supports (131) at the four corners of the top. The pressure rod supports (131) are arranged in a circular array. The pressure rod supports (131) are provided with pressure rod grooves (130) with the opening facing outward. The workpiece pressure rod (110) is installed in the pressure rod grooves (130).

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