High-efficiency multi-section crankshaft heat treatment device

Abstract

The invention relates to a high-efficiency multi-section type crankshaft heat treatment device in the field of heat treatment equipment, in the heating process, shaft necks of the same type are synchronously heated through induction heaters arranged outside the shaft necks of the same type at intervals, the deformation uniformity of the shaft necks of the same type is improved, and the accumulation amount of thermal deformation is reduced. Meanwhile, the adjacent journals are clamped through the clamping rollers on the two sides of the heated journals, so that the journals on the two sides of the heated journals are clamped and fixed, and thermal deformation of the heated journals is reduced; the problem that when a traditional crankshaft is heated, large thermal deformation occurs due to the self-weight acting force or the rotating centrifugal effect is solved, thermal deformation caused by uneven internal stress during crankshaft heat treatment is reduced, and the heat treatment quality is improved. In addition, by arranging the preheating cavity, the heat treatment cavity and the cooling cavity, segmented treatment is achieved, and the energy utilization efficiency is improved through quenching agent recovery and heat exchange.

Description

Technical Field

[0001] The invention relates to a crankshaft heat treatment device, in particular to a high-efficiency multi-stage crankshaft heat treatment device applied in the field of heat treatment equipment. Background Art

[0002] The crankshaft is mainly composed of a crank block and a journal, in which the journal part is subdivided into a main journal located on the center axis of the crankshaft and a connecting rod journal distributed on the periphery of the center axis of the crankshaft. The heat treatment process of the crankshaft covers two major links: overall heat treatment and local heat treatment. In the local heat treatment stage, the journal needs to be subjected to targeted heat treatment. The current heat treatment facilities use an induction heating device to treat the journals one by one. During this process, the crankshaft rotates as a whole to improve the uniformity of heating and reduce the deformation caused by heating. However, since the heat treatment of the journals is carried out sequentially, thermal deformation will occur each time only a single journal is locally heated, and these thermal deformations will continue to accumulate when multiple journals are processed continuously. In addition, under the combined action of its own gravity and the centrifugal force generated by the rotation, the crankshaft will produce a complex stress state inside, further exacerbating the complexity and uncertainty of thermal deformation.

[0003] The existing patent with publication number CN115522035A discloses an automobile crankshaft heat treatment device, comprising an upper frame and a lower frame that can be coupled to each other, the coupling surfaces of the upper frame and the lower frame are both provided with coaxial semicircular openings, the two semicircular openings form a perfect circular opening surrounding the connecting rod journal, a quenching induction head is provided on the perfect circular opening, the quenching induction head can move on the perfect circular opening along the circumference of the connecting rod journal, the upper frame and the lower frame are both provided with a driving component for driving the quenching induction head to move on the perfect circular opening, the present invention couples the upper frame and the lower frame to form a track around which the quenching induction head can surround on the outer periphery of the connecting rod journal, so that the quenching induction head can perform induction heating on the stationary connecting rod journal in a rotating state, thereby avoiding stress concentration caused by the connecting rod journal being inductively heated in a rotating state, thereby improving the stability of the connecting rod journal.

[0004] The above patent uses a rotatable induction heating device to replace the rotation of the crankshaft to achieve uniform heating, improve the stability of the crankshaft during heating, and reduce deformation. However, the crankshaft necks still need to be heated one by one, and the problem of cumulative thermal deformation caused by heating one by one is not overcome. Summary of the invention

[0005] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is that the existing crankshaft heat treatment device needs to heat the journals one by one when performing local heat treatment, which causes accumulation of thermal deformation.

[0006] To solve the above problems, the present invention provides a high-efficiency multi-stage crankshaft heat treatment device, including a box body, a heating mechanism installed in the box body, the heating mechanism including multiple groups of traction heating components arranged opposite to the crankshaft journal, the traction heating component including a mounting ring with an opening at the lower end, a gear ring nested on the inner side of the mounting ring and rotatably connected to the mounting ring, the gear ring is connected to a driving mechanism installed on the mounting ring and driving the gear ring to perform circular motion, a pair of clamping rollers arranged opposite to each other are installed on the inner side of the gear ring, an electric push rod is connected on the outer side of the clamping roller to drive it to perform radial movement, the electric push rod is nested and fixed in the gear ring, the gear ring is fixedly connected to the part between the pair of clamping rollers with an induction heater, and the upper end of the mounting ring is fixedly connected to a first lifting cylinder; the multiple groups of traction heating components are all fixedly connected to a fixing plate fixedly connected to the inner wall of the box body.

[0007] In the above-mentioned high-efficiency multi-stage crankshaft heat treatment device, multiple traction and heating components including clamping rollers and induction heaters are used to synchronously heat the same type of journals on the crankshaft and stably clamp the adjacent journals on both sides of the heated journals to reduce the accumulation of thermal deformation.

[0008] As a further improvement of the present application, a pair of partitions are fixedly connected to the box body, and the partitions divide the inner cavity of the box body from left to right into a preheating chamber, a heat treatment chamber and a cooling chamber. The heating mechanism is fixed in the heat treatment chamber, and a plurality of nozzles corresponding to the shaft necks are provided on the rear side of the heating mechanism. The nozzles are connected to an external quenching agent supply mechanism. The heat treatment chamber is located below the heating mechanism and is provided with a collecting tank. The collecting tank is connected to a heat exchanger arranged below the box body through a pipeline, and the heat exchanger is connected to a heat storage tank. The heat storage tank is connected to the preheating chamber through a first branch pipe, and is connected to the cooling chamber through a second branch pipe.

[0009] As a further improvement of the present application, both the mounting ring and the gear ring are notched circular ring structures and the width of their notches is greater than the diameter of the shaft neck, and the inner end of the mounting ring is provided with an annular groove for accommodating the gear ring.

[0010] As a further improvement of the present application, an arc-shaped groove is provided on the arc-shaped outer wall of the gear ring, and arc-shaped equidistantly distributed latch teeth are fixedly connected to the side walls of the arc-shaped groove. The driving mechanism includes a driving motor fixed on the mounting ring, and the output shaft of the driving motor is fixedly connected to a driving gear nested in the arc-shaped groove, and the driving gear is meshingly connected with the latch teeth.

[0011] As a further improvement of the present application, the clamping roller includes a roller frame and a pair of round rollers nested in the roller frame and rotatably connected to the roller frame, and the line connecting the cross-sectional center of the pair of round rollers and the cross-sectional center of the journal forms an isosceles triangle.

[0012] As a further improvement of the present application, a plurality of nozzles are fixedly connected to the same lifting plate, and the lifting plate is fixedly connected to a second lifting cylinder fixedly connected to the fixed plate.

[0013] As a further improvement of the present application, the box body is a hollow box body, the interior of the box body is fixedly connected with a guide rail, the guide rail is slidably connected with a rail car, the rail car is equipped with motor-driven running wheels, and the running wheels abut against the guide rail.

[0014] As a further improvement of the present application, through holes are provided on the outer walls at both ends of the box and on a pair of partitions for the rail car to pass through. A shielding curtain is provided on the outside of the through holes to reduce heat loss. The guide rail passes through the preheating chamber, the heat treatment chamber and the cooling chamber through the through holes and is fixedly connected to the inner wall of the box.

[0015] As a further improvement of the present application, a first electromagnetic flow valve is provided at the connection point between the first branch pipe and the heat storage tank, a second electromagnetic flow valve is provided at the connection point between the second branch pipe and the heat storage tank, a first temperature sensor is provided in the preheating chamber, a positioning sensor cooperating with the rail car is provided in the heat treatment chamber, and a second temperature sensor is provided in the cooling chamber.

[0016] To summarize, the present invention is provided with multiple groups of traction heating components arranged opposite to each journal. During heating, the induction heaters arranged at intervals outside the journals of the same type are used to heat the journals of the same type synchronously, thereby improving the uniformity of deformation of the journals of the same type, and further improving the uniformity of deformation of the entire crankshaft. At the same time, the clamping rollers on both sides of the heated journal are used to clamp the adjacent journals, so that the journals on both sides of the heated journal are clamped and fixed, thereby reducing the thermal deformation of the heated journal, overcoming the problem of large thermal deformation of the traditional crankshaft due to the force of its own weight or the centrifugal effect of rotation during heating, reducing the thermal deformation caused by uneven internal stress during heat treatment of the crankshaft, and improving the quality of heat treatment. In addition, the clamping rollers are driven by electric push rods to move radially, thereby improving the clamping stability of the crankshaft journals. At the same time, the clamping rollers slide circumferentially on the heated journals along with the gear rings, thereby circumferentially shaping the heated journals, thereby further improving the molding quality of the journals after heat treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the three-dimensional structure of this application;

[0018] Figure 2 This is a schematic diagram of the transverse cross-sectional structure of the present application;

[0019] Figure 3 It is a three-dimensional structural schematic diagram of the heating mechanism in this application;

[0020] Figure 4 It is a schematic diagram of the three-dimensional structure of the traction heating component in this application;

[0021] Figure 5 It is a schematic diagram of the cross-sectional structure of the mounting ring in this application;

[0022] Figure 6It is a schematic diagram of the explosion assembly structure of the mounting ring in this application;

[0023] Figure 7 This is a schematic diagram of the motion state of the gear ring and the clamping roller in this application;

[0024] Figure 8 It is a schematic diagram of the transverse cross-sectional structure of the heating mechanism in this application;

[0025] Fig. 9 It is a schematic diagram of the longitudinal cross-sectional structure of the heating mechanism in this application;

[0026] Fig.10 This is a schematic diagram of the explosion assembly structure of the heating mechanism in this application;

[0027] Fig.11 Schematic diagram of the flow of quenching agent and hot gas flow in this application.

[0028] Description of the numbers in the figure:

[0029] 1. Box body; 101. Preheating chamber; 102. Heat treatment chamber; 103. Cooling chamber; 2. Partition; 3. Through hole; 4. Heating mechanism; 5. Traction heating assembly; 6. Mounting ring; 601. Annular groove; 7. Gear ring; 701. Arc groove; 702. Clamping gear; 8. Driving mechanism; 801. Driving gear; 802. Driving motor; 9. Clamping roller; 901. Roller frame; 902. Round roller; 10. Electric push rod; 11. Induction heater; 12 , the first lifting cylinder; 13, the fixed plate; 14, the rail car; 15, the walking wheel; 16, the guide rail; 17, the nozzle; 18, the lifting plate; 19, the second lifting cylinder; 20, the positioning sensor; 21, the first temperature sensor; 22, the second temperature sensor; 23, the collecting tank; 24, the heat exchanger; 25, the heat storage tank; 26, the first branch pipe; 27, the first electromagnetic flow valve; 28, the second branch pipe; 29, the second electromagnetic flow valve; 30, the blackout curtain. DETAILED DESCRIPTION

[0030] The following describes two implementation modes of the present application in detail with reference to the accompanying drawings.

[0031] The first implementation method:

[0032] Figure 1-8A high-efficiency multi-stage crankshaft heat treatment device is shown, comprising a housing 1, a heating mechanism 4 is installed in the housing 1, the heating mechanism 4 comprises a plurality of traction heating components 5 arranged opposite to the crankshaft journal, the traction heating components 5 comprises a mounting ring 6 with an opening at the lower end, a gear ring 7 rotatably connected to the mounting ring 6 is nested inside the mounting ring 6, the gear ring 7 is connected to a driving mechanism 8 installed on the mounting ring 6 and driving the gear ring 7 to perform circular motion, a pair of clamping rollers 9 arranged opposite to each other are installed inside the gear ring 7, an electric push rod 10 driving the clamping roller 9 to perform radial movement is connected outside the clamping roller 9, the electric push rod 10 is nested and fixed in the gear ring 7, the gear ring 7 is located between the pair of clamping rollers 9 and is fixedly connected to an induction heater 11, and a first lifting cylinder 12 is fixedly connected to the upper end of the mounting ring 6; the plurality of traction heating components 5 are all fixedly connected to a fixing plate 13 fixedly connected to the inner wall of the housing 1.

[0033] For details, please refer to Figure 7 and Figure 8 , when performing crankshaft heating treatment, the following steps are included:

[0034] Step 1: Start the first lifting cylinder 12 of each traction heating assembly 5, so that each mounting ring 6 is sleeved on the outside of the crankshaft journal and the central axis of the mounting ring 6 coincides with the central axis of the corresponding journal (main journal and connecting rod journal). It should be noted that since the crankshaft journal includes the main journal and the connecting rod journal, the descending height of each first lifting cylinder 12 is different;

[0035] Step 2: Start the driving mechanism 8, which drives the gear ring 7 to rotate. The gear ring 7 makes a circular motion and closes the lower end opening of the mounting ring 6. Then start a pair of electric push rods 10, which push the clamping rollers 9 to approach and clamp the journals (main journal and connecting rod journal).

[0036] Step 3: When the main shaft neck needs to be inductively heated, the induction heater 11 on the inner side of the gear ring 7 corresponding to the main shaft neck and the driving mechanism 8 on the outer side of the gear ring 7 corresponding to the main shaft neck are started to rotate and heat the main shaft neck. After the heating is completed, the induction heater 11 and the driving mechanism 8 are turned off, and the gear ring 7 is made to reclose the lower end opening of the mounting ring 6;

[0037] It should be noted that at this time, a pair of clamping rollers 9 on the inner side of the gear ring 7 corresponding to the connecting rod journal clamps the connecting rod journal;

[0038] Step 4: When the connecting rod journal needs to be inductively heated, the induction heater 11 on the inner side of the connecting rod journal corresponding to the gear ring 7 and the driving mechanism 8 on the outer side of the connecting rod journal corresponding to the gear ring 7 are started, so that the induction heater 11 rotates and heats the connecting rod journal until the heating is completed;

[0039] It should be noted that, at this time, the spindle journal is clamped by a pair of clamping rollers 9 in the corresponding gear ring 7;

[0040] Step five, after the main shaft journal and connecting rod journal are heated, start the driving mechanism 8 and electric push rod 10 of each traction and heating assembly 5, so that the clamping roller 9 is out of contact with the journal, and the gear ring 7 returns to the initial position so that the lower end opening of the mounting ring 6 is reopened, and then start the first lifting cylinder 12 to return the mounting ring 6 to the initial position and move it above the crankshaft.

[0041] It should be noted that the induction heater 11 is an electromagnetic induction coil. When an alternating current is passed through it, the magnetic field generated forms an eddy current in the heated conductor, thereby heating the heated conductor. This is a prior art and will not be described in detail in this application.

[0042] Compared with the traditional crankshaft heating and heat treatment device, the present invention is provided with multiple groups of traction heating components 5 arranged opposite to each journal. During heating, the induction heater 11 on the inner side of the traction heating components 5 sleeved on different types of journals is used to heat the same type of journals synchronously, thereby improving the uniformity of deformation of the same type of journals, thereby improving the uniformity of deformation of the entire crankshaft. At the same time, the clamping rollers 9 of the traction heating components 5 on both sides adjacent to the heated journal are used to clamp the adjacent journals, so that the journals on both sides of the heated journal are clamped and fixed, thereby reducing the thermal deformation of the heated journal, overcoming the problem of large thermal deformation of the traditional crankshaft due to the force of its own weight or the centrifugal effect of rotation during heating, reducing the thermal deformation caused by uneven internal stress during crankshaft heat treatment, and improving the quality of heat treatment. In addition, the electric push rod 10 is used to drive the clamping roller 9 to move radially, thereby improving the clamping stability of the crankshaft journal. At the same time, the clamping roller 9 slides circumferentially on the heated journal along with the gear ring 7, thereby circumferentially shaping the heated journal, thereby further improving the molding quality of the journal after heat treatment.

[0043] See also Figure 6 Both the mounting ring 6 and the gear ring 7 are notched circular ring structures, and the width of their notches is greater than the diameter of the shaft neck. The inner end of the mounting ring 6 is provided with an annular groove 601 for accommodating the gear ring 7.

[0044] Specifically, it is convenient for the first lifting cylinder 12 to drive the mounting ring 6 and the gear ring 7 to be sleeved on the outside of the shaft neck and to be separated from the shaft neck.

[0045] See also Figure 6 An arc-shaped groove 701 is provided on the arc-shaped outer wall of the gear ring 7, and arc-shaped equally spaced latch teeth 702 are fixedly connected to the side walls of the arc-shaped groove 701. The driving mechanism 8 includes a driving motor 802 fixed on the mounting ring 6, and the output shaft of the driving motor 802 is fixedly connected to a driving gear 801 nested in the arc-shaped groove 701, and the driving gear 801 is meshed with the latch teeth 702.

[0046] Specifically, the driving motor 802 drives the driving gear 801 to rotate, and the driving gear 801 drives the gear ring 7 to rotate along the annular groove 601 of the mounting ring 6, thereby realizing the circumferential rotation of the induction heater 11 and the clamping roller 9.

[0047] See also Figure 6 The clamping roller 9 includes a roller frame 901 and a pair of round rollers 902 nested in the roller frame 901 and rotatably connected to the roller frame 901. The line connecting the center of the cross section of the pair of round rollers 902 and the center of the cross section of the journal forms an isosceles triangle.

[0048] Specifically, the clamping stability of the shaft neck is improved.

[0049] Second implementation method:

[0050] Figure 2 , Figure 9-11 A high-efficiency multi-stage crankshaft heat treatment device is shown. On the basis of the first embodiment, a pair of partitions 2 are fixedly connected to the housing 1, and the partitions 2 divide the inner cavity of the housing 1 from left to right into a preheating chamber 101, a heat treatment chamber 102 and a cooling chamber 103. The heating mechanism 4 is fixed in the heat treatment chamber 102, and a plurality of nozzles 17 corresponding to the journals are provided on the rear side of the heating mechanism 4. The nozzles 17 are connected to an external quenching agent supply mechanism. The heat treatment chamber 102 is located below the heating mechanism 4 and is provided with a collecting tank 23. The collecting tank 23 is connected to a heat exchanger 24 arranged below the housing 1 through a pipeline. The heat exchanger 24 is connected to a heat storage tank 25. The heat storage tank 25 is connected to the preheating chamber 101 through a first branch pipe 26, and is connected to the cooling chamber 103 through a second branch pipe 28.

[0051] For details, please refer to Fig.11 During the quenching operation, when the heating is completed and the traction heating assembly 5 is separated from the crankshaft, the external quenching agent supply mechanism connected to the nozzle 17 is started, and the nozzle 17 sprays the quenching agent onto the crankshaft. The dripping quenching agent is collected by the collecting tank 23 and transported to the heat exchanger 24. The fan of the heat exchanger 24 generates an airflow to exchange heat with the quenching agent to form hot air. The hot air is transported to the preheating chamber 101 and the cooling chamber 103 respectively through the first branch pipe 26 and the second branch pipe 28, so that the heat is fully utilized. At the same time, the crankshaft to be heated is preheated by the preheating chamber 101, so that the temperature of all parts of the crankshaft has risen evenly before the heat treatment, which is convenient for subsequent heating for heat treatment, reducing energy loss, reducing excessive deformation of the crankshaft caused by sudden heat change, and improving the heat treatment quality of the crankshaft; in addition, by supplementing the heat of the cooling chamber 103, energy loss is reduced and the cooling rate is convenient to control.

[0052] It should be noted that, in order to improve the spraying effect of the nozzles 17 , the plurality of nozzles 17 are fixedly connected to the same lifting plate 18 , and the lifting plate 18 is fixedly connected to a second lifting cylinder 19 fixedly connected to the fixing plate 13 .

[0053] See also Figure 2 The box body 1 is a hollow box body, and a guide rail 16 is fixedly connected to the inside of the box body 1. A rail car 14 is slidably connected to the guide rail 16. A motor-driven running wheel 15 is installed on the rail car 14, and the running wheel 15 abuts against the guide rail 16.

[0054] Specifically, the guide rail 16, the rail car 14 and the running wheel 15 are used to fix the crankshaft and realize the feeding and discharging of the crankshaft.

[0055] See also Figure 2 Through holes 3 for the rail car 14 to pass through are provided on the outer walls at both ends of the box body 1 and a pair of partitions 2. A shielding curtain 30 for reducing heat loss is provided on the outside of the through hole 3. The guide rail 16 passes through the through hole 3 and crosses the preheating chamber 101, the heat treatment chamber 102 and the cooling chamber 103 and is fixedly connected to the inner wall of the box body 1.

[0056] Specifically, the rail car 14 and the guide rail 16 enable the crankshaft to be transferred in different cavities, and to be preheated, heated, cooled in sections, and to be heat recovered by a quenching agent.

[0057] See also Figure 2 A first electromagnetic flow valve 27 is provided at the connection between the first branch pipe 26 and the heat storage tank 25, a second electromagnetic flow valve 29 is provided at the connection between the second branch pipe 28 and the heat storage tank 25, a first temperature sensor 21 is provided in the preheating chamber 101, a positioning sensor 20 cooperating with the rail car 14 is provided in the heat treatment chamber 102, and a second temperature sensor 22 is provided in the cooling chamber 103.

[0058] Specifically, the heat distribution is conveniently controlled by temperature sensors and electromagnetic flow valves. At the same time, the crankshaft journal is accurately aligned with the traction heating assembly 5 through the positioning sensor 20, which is convenient for subsequent heating treatment. It should be noted that the motor connected to the walking wheel 15 is equipped with a Hall sensor to monitor the travel distance of the rail car 14. There is no need to perform high-precision positioning of the rail car and the crankshaft thereon in the preheating chamber 101 and the cooling chamber 103.

[0059] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A high-efficiency multi-stage crankshaft heat treatment device, characterized in that: The invention comprises a housing (1), wherein a heating mechanism (4) is installed in the housing (1), wherein the heating mechanism (4) comprises a plurality of traction heating components (5) arranged opposite to the crankshaft journals, wherein the traction heating components (5) comprise a mounting ring (6) having an opening at the lower end, wherein a gear ring (7) is embedded inside the mounting ring (6) and is rotatably connected thereto, wherein the gear ring (7) is connected to a driving mechanism (8) installed on the mounting ring (6) and driving the gear ring (7) to perform circular motion, wherein a pair of The clamping rollers (9) are arranged opposite to each other, and the outer side of the clamping rollers (9) is connected to an electric push rod (10) for driving the clamping rollers to move radially. The electric push rod (10) is nested and fixed in the gear ring (7). The gear ring (7) is located between the pair of clamping rollers (9) and is fixedly connected to an induction heater (11). The upper end of the mounting ring (6) is fixedly connected to a first lifting cylinder (12); multiple groups of the traction heating components (5) are fixedly connected to a fixing plate (13) fixedly connected to the inner wall of the box body (1).

2. A high-efficiency multi-stage crankshaft heat treatment device according to claim 1, characterized in that: The box body (1) is fixedly connected to a pair of partitions (2), the partitions (2) divide the inner cavity of the box body (1) from left to right into a preheating cavity (101), a heat treatment cavity (102) and a cooling cavity (103), the heating mechanism (4) is fixed in the heat treatment cavity (102), a plurality of nozzles (17) corresponding to the journals are arranged on the rear side of the heating mechanism (4), the nozzles (17) are connected to an external quenching agent supply mechanism, the heat treatment cavity (102) is provided with a collecting tank (23) below the heating mechanism (4), the collecting tank (23) is connected to a heat exchanger (24) arranged below the box body (1) through a pipeline, the heat exchanger (24) is connected to a heat storage tank (25), the heat storage tank (25) is connected to the preheating cavity (101) through a first branch pipe (26), and is connected to the cooling cavity (103) through a second branch pipe (28).

3. The high-efficiency multi-stage crankshaft heat treatment device according to claim 1, characterized in that: The mounting ring (6) and the gear ring (7) are both notched annular structures and the width of the notches of both are greater than the diameter of the shaft neck. The inner end of the mounting ring (6) is provided with an annular groove (601) for accommodating the gear ring (7).

4. A high-efficiency multi-stage crankshaft heat treatment device according to claim 3, characterized in that: The gear ring (7) has an arc-shaped groove (701) on its arc-shaped outer wall, and arc-shaped equally spaced latch teeth (702) are fixedly connected to the side wall of the arc-shaped groove (701). The driving mechanism (8) comprises a driving motor (802) fixed to the mounting ring (6), and the output shaft of the driving motor (802) is fixedly connected to a driving gear (801) nested in the arc-shaped groove (701), and the driving gear (801) is meshedly connected to the latch teeth (702).

5. The high-efficiency multi-stage crankshaft heat treatment device according to claim 1, characterized in that: The clamping roller (9) comprises a roller frame (901) and a pair of round rollers (902) nested in the roller frame (901) and rotatably connected to the roller frame (901); a line connecting the center of the cross section of the pair of round rollers (902) and the center of the cross section of the journal forms an isosceles triangle.

6. A high-efficiency multi-stage crankshaft heat treatment device according to claim 2, characterized in that: The plurality of spray heads (17) are fixedly connected to the same lifting plate (18), and the lifting plate (18) is fixedly connected to a second lifting cylinder (19) fixedly connected to the fixed plate (13).

7. The high-efficiency multi-stage crankshaft heat treatment device according to claim 2, characterized in that: The box body (1) is a hollow box body, the interior of the box body (1) is fixedly connected with a guide rail (16), a rail vehicle (14) is slidably connected to the guide rail (16), a motor-driven running wheel (15) is installed on the rail vehicle (14), and the running wheel (15) abuts against the guide rail (16).

8. The high-efficiency multi-stage crankshaft heat treatment device according to claim 7, characterized in that: Through holes (3) for the rail vehicle (14) to pass through are provided on the outer walls at both ends of the box body (1) and on a pair of partitions (2). A shielding curtain (30) for reducing heat loss is provided on the outside of the through hole (3). The guide rail (16) passes through the preheating chamber (101), the heat treatment chamber (102) and the cooling chamber (103) through the through hole (3) and is fixedly connected to the inner wall of the box body (1).

9. The high-efficiency multi-stage crankshaft heat treatment device according to claim 8, characterized in that: A first electromagnetic flow valve (27) is provided at the connection point between the first branch pipe (26) and the heat storage tank (25), a second electromagnetic flow valve (29) is provided at the connection point between the second branch pipe (28) and the heat storage tank (25), a first temperature sensor (21) is provided in the preheating chamber (101), a positioning sensor (20) cooperating with the rail car (14) is provided in the heat treatment chamber (102), and a second temperature sensor (22) is provided in the cooling chamber (103).

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