Induction heating device for scraper conveyor chain wheel and strengthening method
By optimizing the design of the induction heating device and the segmented quenching method, the problem of uneven heating inside the chain socket was solved, thereby improving the wear resistance of the sprocket and extending the service life of the equipment.
Patent Information
- Application Number
- CN202511181353.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-12-12
AI Technical Summary
During induction hardening, the induced heat at the top and bottom surfaces of the chain tooth socket is high, while the heat inside the chain socket is low. This makes it impossible to achieve targeted hardening of the chain socket, resulting in poor wear resistance.
The design employs a U-shaped frame, a first conductor, and two second conductors to form an induction heating cavity. By combining the protruding structure in the middle of the first conductor and the contoured induction surface of the second conductor, the magnetic field distribution is optimized. The contoured induction surface forms a small gap with the inside of the chain socket and a large gap with the tooth top and bottom planes, ensuring that the inside of the chain socket is fully heated. The uniformity of the hardened layer is achieved by segmented quenching and spraying quenching liquid.
It improves the heating efficiency and hardening effect inside the chain socket, enhances the wear resistance of the sprocket, meets the wear resistance requirements of different parts of the sprocket, and extends the service life of the equipment.
Smart Images
Figure CN121109725A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of surface strengthening technology, and in particular to an induction heating device and strengthening method for scraper conveyor sprockets. Background Technology
[0002] Currently, scraper conveyors are one of the key pieces of equipment in fully mechanized mining operations in coal mines. They use the meshing of sprockets and chains to drive the scraper conveyor. Through the closed-loop meshing of the scraper chain, coal and coal mixtures are transported from the head to the tail of the machine in the chute to complete unloading.
[0003] During equipment operation, the chain and sprocket repeatedly engage, disengage, and retract. During these actions, the sprocket and chain are subjected to enormous alternating and impact loads. Simultaneously, coal and gangue enter the meshing area, generating sliding friction and abrasive wear, while water adheres to the sprocket surface, causing corrosion. Therefore, frequent wear during operation leads to structural damage to the sprocket, requiring shutdown and replacement of the sprocket and shaft assembly. This fails to meet the requirements for reliable coal conveying in mines, impacting production efficiency.
[0004] Existing sprocket strengthening processes mainly include surface additive manufacturing and surface hardening. Surface hardening includes flame hardening, induction hardening, salt bath hardening, and carburizing hardening. Induction hardening is widely used due to its advantages such as high precision, good hardening quality, high efficiency, and good controllability. For example... Figure 1 As shown, due to the special contour of the sprocket tooth 1, the induced heat at the top 11 and bottom plane 12 of the chain socket tooth may be higher than the upper limit, while the heat inside the chain socket 10 is lower, which cannot achieve targeted hardening treatment inside the chain socket, and the problem of poor wear resistance still exists. Summary of the Invention
[0005] The technical problem to be solved by this invention is that during induction hardening, the induced heat at the top and bottom planes of the chain tooth socket is high, while the heat inside the chain socket is low, which makes it impossible to achieve targeted hardening treatment inside the chain socket, resulting in poor wear resistance.
[0006] To solve the above-mentioned technical problems, the present invention provides a technical solution for an induction heating device for a scraper conveyor sprocket: The induction heating device for the sprocket of a scraper conveyor includes a U-shaped frame, a first conductor and two second conductors. The two second conductors are symmetrically arranged inside the U-shaped frame, and the first conductor is connected to the two second conductors on the side near the U-shaped opening. The first conductor and the two second conductors form an induction heating cavity. The middle part of the first conductor protrudes into the interior of the U-shaped frame. The first conductor is used to make clearance fit with the axial end face of the sprocket teeth during induction heating. The second conductor includes a copper tube and a plurality of magnetic sheets. The plurality of magnetic sheets are fixedly disposed on the copper tube of the second conductor, and the plurality of magnetic sheets are spliced together to form a contoured sensing surface. The contoured sensing surface has a protruding portion close to the first conductor. The protruding portion is used to form a first gap with the inside of the chain socket during induction heating. The contour-following induction surface also has a main body portion, which surrounds the outer edge of the protruding portion away from the first conductor. The main body portion is used to form a second gap with the top and bottom planes of the chain tooth during induction heating, and the first gap is smaller than the second gap.
[0007] Furthermore, the first gap is any size from 3mm to 5mm, and the second gap is any size from 8mm to 10mm.
[0008] Furthermore, the first conductor has a U-shaped outline, and the distance between the first conductor and the axial end face of the sprocket teeth during induction heating is any size from 9mm to 12mm.
[0009] Furthermore, it also includes two third conductors, which are symmetrically arranged inside the U-shaped frame. The two third conductors are arranged on the side of the two second conductors away from the first conductor. The third conductors are used to make clearance fit with the outer circle contour of the sprocket teeth during induction heating. The distance between the third conductors and the outer circle contour of the sprocket teeth is any size of 14mm to 16mm.
[0010] Furthermore, it also includes a water supply structure, wherein an inlet pipe is connected between the water supply structure and the copper pipe of one of the second conductors, and a return pipe is connected between the water supply structure and the copper pipe of another second conductor. The first conductor is a hollow tube and connects the copper pipe of the first conductor and the copper pipe of the second conductor.
[0011] To address the aforementioned technical problems, this invention provides a technical solution for strengthening sprockets in scraper conveyors: A method for strengthening sprockets in scraper conveyors, the method employing the aforementioned induction heating device for scraper conveyor sprockets, includes the following steps: S1. Install the sprocket on the quenching machine tool and center and position it; S2. Install the induction heating device, adjust the quenching induction position according to the sprocket teeth, and keep the protruding part of the contour induction surface of the two second conductors consistent with the first gap between the inside of the two chain sockets, and keep the main body of the contour induction surface of the two second conductors consistent with the second gap between the top and bottom planes of the two chain socket teeth. S3. Input the parameters of the sprocket outer diameter, number of teeth, and rotation speed. The quenching machine tool will automatically index the sprocket through the indexing plate to determine the rotation angle required for each quenching. S4. Set the working parameters of the induction heating device, and perform the heating conduction-austenitization process and the uniform temperature diffusion process in sequence according to the segmented quenching method to obtain a hardened layer with a hardness gradient distribution. S5. After the sprocket teeth are quenched and heated, the induction heating device moves to the clearance position, and the quenching machine tool moves the sprocket teeth to the quenching liquid spraying position to complete the supercooling adaptive process. While the quenching liquid is being sprayed, the induction heating device automatically moves forward and automatically aligns and heats the next sprocket teeth according to the working parameters of the previous sprocket teeth. S6. After the upper sprocket teeth are all quenched, the sprocket is placed in a heat-holding furnace for tempering. S7. After tempering, perform quenching and tempering treatment on the lower sprocket teeth according to steps S1 to S5.
[0012] Furthermore, it also includes: in step S8, after quenching and tempering, the hardness inside the chain socket is greater than the hardness of the chain, and the hardness difference is any size from 3HRC to 5HRC.
[0013] Furthermore, in step S4, the quenching frequency is set to any value between 2.7KHz and 3.5KHz. The segmented quenching includes: a first quenching stage with a heating power of 60% of the rated power and a heating delay of 230s; a second quenching stage with a heating power of 0 and a heating delay of 25s; a third quenching stage with a heating power of 60% of the rated power and a heating delay of 120s; and a fourth quenching stage with a heating power of 0 and a heating delay of 20s. The heat conduction-austenitization process is completed through the first to the fourth quenching stages. The fifth quenching stage has a heating power of 60% of the rated power and a heating delay of 60s; the sixth quenching stage has a heating power of 0 and a heating delay of 10s; the seventh quenching stage has a heating power of 40% of the rated power and a heating delay of 10s; the uniform temperature diffusion process is completed after passing through the fifth to the seventh quenching stages. In the first cooling section, the quenching liquid is sprayed for 80 seconds; in the second cooling section, the spraying stops for 5 seconds; in the third cooling section, the quenching liquid is sprayed again for 60 seconds; the supercooling adaptive process is completed from the first cooling section to the third cooling section.
[0014] Furthermore, in step S5, after the previous sprocket tooth is quenched and heated, the quenching machine tool operates to drive the next sprocket tooth into the quenching station, and there is at least one sprocket tooth between the previous sprocket tooth and the next sprocket tooth.
[0015] Furthermore, before step S1, the sprocket blank is forged using 40CrNiMoA material and then normalized after forging. The sprocket blank is rough machined to form the inner hole, stepped hole, overall length, relief groove and vertical ring groove, controlling the inner hole tolerance ≤ ±0.5mm and the surface roughness ≤ Ra3.2, while ensuring the coaxiality of the holes on both sides; the sprocket blank is rough milled to form the tooth profile and chain socket. First, heat to 800℃, then cool with quenching liquid, and then temper at 470℃ to obtain a sprocket semi-finished product; the tempering hardness reaches 300HB~320HB, the microstructure reaches tempered sorbite grade 1~4, and the grain size is grade 6 or above. Semi-finishing is performed on the sprocket semi-finished product, including semi-finishing the inner hole, stepped hole, overall length and vertical ring groove, and finish machining the sprocket teeth to the required dimensions of the part; the minimum inner hole tolerance is ≤ ±0.2, the surface roughness is ≤ Ra3.2, and the coaxiality of the holes on both sides is ensured at the same time; finish milling is performed on the sprocket tooth profile and sprocket sprocket socket to the required dimensions of the part.
[0016] Compared with existing technologies, the induction heating device and strengthening method for scraper conveyor sprockets of the present invention have the following advantages: The induction heating device for scraper conveyor sprockets adopts a design of a U-shaped frame, a first conductor, and two second conductors. The two second conductors are symmetrically arranged inside the U-shaped frame, and the first conductor is connected to the two second conductors on the side near the U-shaped opening. The U-shaped frame provides support and fixation for the first and second conductors and reserves accommodating space for the sprocket teeth. The first conductor and the two second conductors form an induction heating cavity. Combined with the protruding structure in the middle of the first conductor and the contoured induction surface of the second conductor, a spatial coupling matching the sprocket teeth and chain groove contour is formed. It is precisely this three-dimensional contoured structure design that reduces magnetic field leakage, concentrates the induced eddy current inside the chain groove and on the axial end face of the sprocket teeth, and improves energy utilization.
[0017] The second conductor is a combination of a copper tube and multiple magnetic sheets. The copper tube has high conductivity, and the multiple magnetic sheets are spliced together to form a contoured induction surface, which can precisely adjust the magnetic field distribution and optimize the temperature gradient between the tooth tip and the chain socket. The gap between the protruding part of the contoured induction surface and the inside of the chain socket is smaller, which enhances the magnetic field strength in this area and ensures that the inside of the chain socket is fully heated. The gap between the main body and the tooth tip and bottom plane of the chain socket is larger, which avoids overheating at the edge and achieves uniformity in the depth and contour of the hardened layer. The design of the first gap being larger than the second gap compensates for the difference in the "skin effect" of the electromagnetic field, preferentially applying a stronger induced current to the inside of the chain socket. Differential heating can achieve targeted hardening treatment inside the chain socket, meeting the wear resistance requirements of different parts of the sprocket. Attached Figure Description
[0018] Figure 1 This is a partial schematic diagram of a sprocket and sprocket socket in the background art; Figure 2 This is a perspective view of an induction heating device for a scraper conveyor sprocket according to an embodiment of the present invention; Figure 3 This is a perspective view of an induction heating device for a scraper conveyor sprocket according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the quenching process of the induction heating device and the sprocket teeth according to an embodiment of the present invention; Figure 5 This is a partial enlarged view of the induction heating device and sprocket teeth according to an embodiment of the present invention; Figure 6 This is a hardness distribution diagram of the sprocket teeth after strengthening treatment according to an embodiment of the present invention; In the diagram: 1. Sprocket teeth; 10. Inside the chain socket; 11. Top of the chain socket teeth; 12. Tooth bottom plane; 2. U-shaped frame; 20. Induction heating chamber; 3. First conductor; 4. Second conductor; 40. Magnetic sheet; 41. Contour-following induction surface; 42. Protruding part; 43. Main body; 5. Third conductor; 6. Water supply structure; 61. Water inlet pipe; 62. Water return pipe. Detailed Implementation
[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" used to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0023] like Figures 2 to 5 As shown, an induction heating device for a scraper conveyor sprocket according to an embodiment of the present invention includes a U-shaped frame 2, a first conductor 3 and two second conductors 4. The two second conductors 4 are symmetrically arranged inside the U-shaped frame 2. The first conductor 3 is connected to the two second conductors 4 on the side near the U-shaped opening. The first conductor 3 and the two second conductors 4 form an induction heating cavity 20. The middle part of the first conductor 3 protrudes towards the inside of the U-shaped frame. The first conductor 3 is used to make clearance fit with the axial end face of the sprocket tooth 1 during induction heating.
[0024] The second conductor 4 includes a copper tube (not shown in the figure) and a plurality of magnetic sheets 40. The plurality of magnetic sheets 40 are fixed on the copper tube of the second conductor 4, and the plurality of magnetic sheets 40 are spliced together to form a contour sensing surface 41. The contour sensing surface 41 has a protruding portion 42 close to the first conductor 3. The protruding portion 42 is used to form a first gap with the inside of the chain socket 10 during induction heating. The contour sensing surface 41 also has a main body portion 43. The main body portion 43 is distributed around the outer edge of the protruding portion 42 away from the first conductor 3. The main body portion 43 is used to form a second gap with the top 11 and bottom plane 12 of the chain socket tooth during induction heating, and the first gap is smaller than the second gap.
[0025] The induction heating device for the sprocket of a scraper conveyor adopts a design consisting of a U-shaped frame 2, a first conductor 3, and two second conductors 4. The two second conductors 4 are symmetrically arranged inside the U-shaped frame 2, and the first conductor 3 is connected to the two second conductors 4 on the side near the U-shaped opening. The U-shaped frame 2 provides support and fixation for the first conductor 3 and the second conductors 4, and also provides a space for the sprocket teeth 1. The first conductor 3 and the two second conductors 4 together form an induction heating cavity 20. Combined with the protruding structure in the middle of the first conductor 3 and the contoured induction surface 41 of the second conductor 4, a spatial coupling matching the contour of the sprocket teeth 1 and the chain groove is formed. It is precisely this three-dimensional contoured structure design that reduces magnetic field leakage and concentrates the induced eddy currents inside the chain groove 10 and on the axial end face of the sprocket teeth 1, thereby improving energy utilization.
[0026] The second conductor 4 is a combination of a copper tube and multiple magnetic sheets 40. The copper tube has high conductivity, and the multiple magnetic sheets 40 are spliced together to form a contoured induction surface 41, which can precisely adjust the magnetic field distribution and optimize the temperature gradient between the tooth tip and the chain socket. The gap between the protruding part 42 of the contoured induction surface 41 and the inside of the chain socket 10 is smaller, which enhances the magnetic field strength in this area and ensures that the inside of the chain socket 10 is fully heated. The gap between the main body 43 and the tooth tip 11 and tooth bottom plane 12 of the chain socket is larger, which avoids overheating at the edge and achieves uniformity in the depth and contour of the hardened layer. The design of the first gap being larger than the second gap compensates for the difference in the "skin effect" of the electromagnetic field, preferentially applying a stronger induced current to the inside of the chain socket 10. Differential heating can achieve targeted hardening treatment of the inside of the chain socket 10, meeting the wear resistance requirements of different parts of the sprocket.
[0027] In this embodiment, the first gap is any size from 3mm to 5mm, and the second gap is any size from 8mm to 10mm. Furthermore, the outline of the first conductor 3 is Z-shaped, and the distance between the first conductor 3 and the axial end face of the sprocket tooth 1 during induction heating is any size from 9mm to 12mm. Specifically, during induction heating, the first gap is 4mm, the second gap is 9mm, and the distance between the first conductor 3 and the axial end face of the sprocket tooth 1 is 10mm.
[0028] The induction heating device also includes two third conductors 5, which are symmetrically arranged inside the U-shaped frame 2. The two third conductors 5 are correspondingly positioned on the side of the two second conductors 4 away from the first conductor 3. The third conductors 5 are used to engage with the outer contour of the sprocket tooth 1 during induction heating. The distance between the third conductor 5 and the outer contour of the sprocket tooth 1 is any size, ranging from 14mm to 16mm. Specifically, during induction heating, the distance between the third conductor 5 and the outer contour of the sprocket tooth 1 is 15mm. Through this differentiated gap design, the goal of uniform heating of the sprocket tooth 1 as a whole and targeted strengthening of specific areas is achieved.
[0029] In addition, the induction heating device also includes a water supply structure 6. A water inlet pipe 61 connects the water supply structure 6 to the copper pipe of one of the second conductors 4, and a water return pipe 62 connects the water supply structure 6 to the copper pipe of another second conductor 4. The first conductor 3 is a hollow tube and connects the copper pipes of the first conductor 3 and the second conductor 4. The water supply structure 6 circulates water through the water inlet pipe 61 into the copper pipes of the second conductor 4, the first conductor 3, and the third conductor 5 to prevent the copper pipes from overheating and being damaged, thus ensuring the reliability of the induction heating.
[0030] A method for strengthening sprockets in scraper conveyors, the method employing the aforementioned induction heating device for scraper conveyor sprockets, includes the following steps: S1. Install the sprocket on the quenching machine and center it.
[0031] S2. Install the induction heating device, adjust the quenching induction position according to the sprocket tooth 1, and keep the protruding part 42 of the contour induction surface 41 of the two second conductors 4 consistent with the first gap between the inside 10 of the two chain sockets, and keep the main body part 43 of the contour induction surface 41 of the two second conductors 4 consistent with the second gap between the top 11 and bottom plane 12 of the two chain socket teeth.
[0032] S3. Input the parameters of the sprocket outer diameter, number of teeth, and rotation speed. The quenching machine tool will automatically index the sprocket using its indexing plate to determine the rotation angle required for each quenching operation.
[0033] S4. Set the working parameters of the induction heating device, and perform the heating conduction-austenitization process and uniform temperature diffusion process in sequence according to the segmented quenching method to obtain a hardened layer with a hardness gradient distribution.
[0034] In step S4, the quenching frequency is set to any value between 2.7 kHz and 3.5 kHz, and the segmented quenching includes: The first quenching stage has a heating power of 60% of the rated power and a heating delay of 230s; the second quenching stage has a heating power of 0 and a heating delay of 25s; the third quenching stage has a heating power of 60% of the rated power and a heating delay of 120s; the fourth quenching stage has a heating power of 0 and a heating delay of 20s; the heating conduction-austenitization process is completed through the first to the fourth quenching stages.
[0035] The fifth quenching stage has a heating power of 60% of the rated power and a heating delay of 60s; the sixth quenching stage has a heating power of 0 and a heating delay of 10s; the seventh quenching stage has a heating power of 40% of the rated power and a heating delay of 10s; the uniform temperature diffusion process is completed after passing through the fifth to the seventh quenching stages.
[0036] In the first cooling section, the quenching liquid is sprayed for 80 seconds; in the second cooling section, the spraying stops for 5 seconds; in the third cooling section, the quenching liquid is sprayed again for 60 seconds; the supercooling adaptive process is completed from the first cooling section to the third cooling section.
[0037] S5. After the quenching and heating of sprocket tooth 1 is completed, the induction heating device retracts to the clearance position, and the quenching machine tool drives sprocket tooth 1 to the quenching liquid spraying position to complete the supercooling adaptive process. Simultaneously with the spraying of the quenching liquid, the induction heating device automatically moves forward, automatically aligning and quenching the next sprocket tooth 1 according to the working parameters of the previous sprocket tooth 1. In step S5, after the quenching and heating of the previous sprocket tooth 1 is completed, the quenching machine tool operates, driving the next sprocket tooth 1 into the quenching position, with at least one sprocket tooth 1 spaced between the previous and next sprocket tooth 1.
[0038] S6. After the upper sprocket teeth 1 are quenched, the sprocket is placed in a holding furnace for tempering treatment. The tempering temperature is set to 180℃ and held for 4 hours.
[0039] S7. After tempering, perform quenching and tempering treatment on the lower sprocket teeth 1 according to steps S1 to S5.
[0040] S8. After quenching and tempering, the hardness of the sprocket tooth 10 inside the chain socket should be greater than the hardness of the chain, with the hardness difference between the two being any value between 3HRC and 5HRC. This avoids severe chain wear due to excessive hardness difference. After surface strengthening, the sprocket tooth 1 is sliced along the radial plane, and the hardness at each location is tested. Figure 6 As shown, the overall surface hardness distribution of the sprocket tooth 1 is uniform, and the hardness of the chain socket 10 is effectively strengthened.
[0041] It should be noted that before step S1, the sprocket blank is forged using 40CrNiMoA material and then normalized after forging.
[0042] The sprocket blank is rough machined to form the inner hole, stepped hole, overall length, relief groove and vertical ring groove, controlling the inner hole tolerance ≤ ±0.5mm and the surface roughness ≤ Ra3.2, while ensuring the coaxiality of the holes on both sides; the sprocket blank is rough milled to form the tooth profile and chain socket.
[0043] First, heat to 800℃, then cool with quenching liquid, and then temper at 470℃ to obtain a sprocket semi-finished product; the tempering hardness reaches 300HB~320HB, the microstructure reaches tempered sorbite grade 1~4, and the grain size is grade 6 or above.
[0044] Semi-finishing is performed on the sprocket semi-finished product, including semi-finishing the inner hole, stepped hole, overall length and vertical ring groove, and finish machining the sprocket teeth 1 to the required dimensions of the part; the minimum inner hole tolerance is ≤ ±0.2, the surface roughness is ≤ Ra3.2, and the coaxiality of the holes on both sides is ensured at the same time; finish milling is performed on the sprocket tooth profile and sprocket chain socket to the required dimensions of the part.
[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.
Claims
1. An induction heating device for a scraper conveyor sprocket, characterized in that, It includes a U-shaped frame, a first conductor, and two second conductors. The two second conductors are symmetrically arranged inside the U-shaped frame, and the first conductor is connected to the two second conductors on the side near the U-shaped opening. The first conductor and the two second conductors form an induction heating cavity. The middle part of the first conductor protrudes into the interior of the U-shaped frame. The first conductor is used to make clearance fit with the axial end face of the sprocket teeth during induction heating. The second conductor includes a copper tube and a plurality of magnetic sheets. The plurality of magnetic sheets are fixedly disposed on the copper tube of the second conductor, and the plurality of magnetic sheets are spliced together to form a contoured sensing surface. The contoured sensing surface has a protruding portion close to the first conductor. The protruding portion is used to form a first gap with the inside of the chain socket during induction heating. The contour-following induction surface also has a main body portion, which surrounds the outer edge of the protruding portion away from the first conductor. The main body portion is used to form a second gap with the top and bottom planes of the chain tooth during induction heating, and the first gap is smaller than the second gap.
2. The induction heating device for a scraper conveyor sprocket according to claim 1, characterized in that, The first gap is any size from 3mm to 5mm, and the second gap is any size from 8mm to 10mm.
3. The induction heating device for a scraper conveyor sprocket according to claim 1, characterized in that, The first conductor has a U-shaped outline, and the distance between the first conductor and the axial end face of the sprocket teeth during induction heating is any size from 9mm to 12mm.
4. The induction heating device for a scraper conveyor sprocket according to claim 1, characterized in that, It also includes two third conductors, which are symmetrically arranged inside the U-shaped frame. The two third conductors are arranged on the side of the two second conductors away from the first conductor. The third conductors are used to make clearance fit with the outer circle contour of the sprocket teeth during induction heating. The distance between the third conductors and the outer circle contour of the sprocket teeth is any size of 14mm to 16mm.
5. The induction heating device for a scraper conveyor sprocket according to claim 1, characterized in that, It also includes a water supply structure, wherein an inlet pipe is connected between the water supply structure and the copper pipe of one of the second conductors, and a return pipe is connected between the water supply structure and the copper pipe of another of the second conductors. The first conductor is a hollow tube and connects the copper pipe of the first conductor and the copper pipe of the second conductor.
6. A method for strengthening sprockets in scraper conveyors, characterized in that, The strengthening method employs the induction heating device for scraper conveyor sprockets as described in claim 1, and includes the following steps: S1. Install the sprocket on the quenching machine tool and center and position it; S2. Install the induction heating device, adjust the quenching induction position according to the sprocket teeth, and keep the protruding part of the contour induction surface of the two second conductors consistent with the first gap between the inside of the two chain sockets, and keep the main body of the contour induction surface of the two second conductors consistent with the second gap between the top and bottom planes of the two chain socket teeth. S3. Input the parameters of the sprocket outer diameter, number of teeth, and rotation speed. The quenching machine tool will automatically index the sprocket through the indexing plate to determine the rotation angle required for each quenching. S4. Set the working parameters of the induction heating device, and perform the heating conduction-austenitization process and the uniform temperature diffusion process in sequence according to the segmented quenching method to obtain a hardened layer with a hardness gradient distribution. S5. After the sprocket teeth are quenched and heated, the induction heating device moves to the clearance position, and the quenching machine tool moves the sprocket teeth to the quenching liquid spraying position to complete the supercooling adaptive process. While the quenching liquid is being sprayed, the induction heating device automatically moves forward and automatically aligns and heats the next sprocket teeth according to the working parameters of the previous sprocket teeth. S6. After the upper sprocket teeth are all quenched, the sprocket is placed in a heat-holding furnace for tempering. S7. After tempering, perform quenching and tempering treatment on the lower sprocket teeth according to steps S1 to S5.
7. The method for strengthening sprockets for scraper conveyors according to claim 6, characterized in that, it further... include: Step S8: After quenching and tempering, the hardness inside the chain socket is greater than the hardness of the chain, and the hardness difference is any value between 3HRC and 5HRC.
8. The method for strengthening sprockets for scraper conveyors according to claim 6, characterized in that, In step S4, the quenching frequency is set to any value between 2.7 kHz and 3.5 kHz, and the segmented quenching includes: The first quenching stage has a heating power of 60% of the rated power and a heating delay of 230s; the second quenching stage has a heating power of 0 and a heating delay of 25s; the third quenching stage has a heating power of 60% of the rated power and a heating delay of 120s; the fourth quenching stage has a heating power of 0 and a heating delay of 20s; the heating conduction-austenitization process is completed through the first to the fourth quenching stages. The fifth quenching stage has a heating power of 60% of the rated power and a heating delay of 60s; the sixth quenching stage has a heating power of 0 and a heating delay of 10s; the seventh quenching stage has a heating power of 40% of the rated power and a heating delay of 10s; the uniform temperature diffusion process is completed after passing through the fifth to the seventh quenching stages. In the first cooling section, the quenching liquid is sprayed for 80 seconds; in the second cooling section, the spraying stops for 5 seconds; in the third cooling section, the quenching liquid is sprayed again for 60 seconds; the supercooling adaptive process is completed from the first cooling section to the third cooling section.
9. The method for strengthening sprockets for scraper conveyors according to claim 6, characterized in that, In step S5, after the previous sprocket tooth is quenched and heated, the quenching machine tool drives the next sprocket tooth into the quenching station, and there is at least one sprocket tooth between the previous sprocket tooth and the next sprocket tooth.
10. The method for strengthening a sprocket for a scraper conveyor according to claim 6, characterized in that, Before step S1, the sprocket blank is forged using 40CrNiMoA material and then normalized after forging. The sprocket blank is rough machined to form the inner hole, stepped hole, overall length, relief groove and vertical ring groove, controlling the inner hole tolerance ≤ ±0.5mm and the surface roughness ≤ Ra3.2, while ensuring the coaxiality of the holes on both sides; the sprocket blank is rough milled to form the tooth profile and chain socket. First, heat to 800℃, then cool with quenching liquid, and then temper at 470℃ to obtain a sprocket semi-finished product; the tempering hardness reaches 300HB~320HB, the microstructure reaches tempered sorbite grade 1~4, and the grain size is grade 6 or above. Semi-finishing is performed on the sprocket semi-finished product, including semi-finishing the inner hole, stepped hole, overall length and vertical ring groove, and finish machining the sprocket teeth to the required dimensions of the part; the minimum inner hole tolerance is ≤ ±0.2, the surface roughness is ≤ Ra3.2, and the coaxiality of the holes on both sides is ensured at the same time; finish milling is performed on the sprocket tooth profile and sprocket sprocket socket to the required dimensions of the part.