A heat treatment furnace for a coil spring and a heat treatment method

Abstract

The present application relates to heat treatment equipment technical field, specifically relates to a kind of spiral spring heat treatment furnace, including furnace body, roll shaft, main controller, first lifting assembly, the furnace body is equipped with multiple parallel roll shafts, the end shaft section of both ends of each roll shaft is assembled on furnace body by bearing, it is equipped with a cross bar between adjacent roll shafts in the furnace body, the both ends of cross bar are respectively fixed on an independent first lifting assembly, first lifting assembly drives cross bar to lift, the end shaft section of roll shaft one end is mechanically connected with driving motor by transmission mechanism.The spinning process of roll shaft, the spinning of spiral spring workpiece is carried out, so that it is heated evenly in heat treatment furnace, so that product performance is more uniform, the function of transporting spiral spring rearward is realized by the lifting of cross bar.

Description

Technical Field

[0001] This invention relates to the field of heat treatment furnace technology, and specifically to a helical spring heat treatment furnace and heat treatment method. Background Technology

[0002] A spring is a mechanical part that works by utilizing elasticity. The main types include helical springs, spiral springs, leaf springs, and irregularly shaped springs. Helical springs are a commonly used type. During the manufacturing process of helical springs, heat treatment furnaces are often required, such as tempering heat treatment to remove residual stress. Currently, the internal transport method of helical spring heat treatment furnaces uses a "V"-shaped track. The helical spring moves forward within the track grooves for heat treatment. Its advantage is that it can stabilize the spring within the "V" grooves, but it also has the following disadvantages:

[0003] 1. Because its track groove is V-shaped and its heat source is a natural gas nozzle above the heat treatment furnace, the helical spring is located in the track groove. Its upper part quickly reaches the tempering temperature, while the lower part is blocked by the V groove and the temperature rises slowly or even cannot reach the tempering temperature. This results in uneven heating of the helical spring. The different tempering times lead to uneven distribution of the spring's mechanical properties. Moreover, the spring remains in the track groove and its state does not change. The upper part is closer to the heat source and has a higher temperature, while the lower part is farther from the heat source and has a lower temperature. The uneven heating seriously affects the quality of the spring.

[0004] Second, because its movement inside the furnace is driven by tracks, and the movement of the tracks is a cyclic process, with a pit below as the circulation space for the tracks, and the furnace length can reach about 20 meters, the temperature of the tracks outside the furnace drops significantly. When the tracks circulate back into the furnace, they reabsorb heat from inside the furnace, resulting in energy waste. Approximately 70% of the heat is lost during the process, leading to energy waste and increased production costs.

[0005] Third, because its tracks have an external furnace section, the external furnace section requires a pit that occupies a large area. In addition, the tracks repeatedly participate in the heating and cooling cycle, which causes thermal fatigue. The tracks themselves are heavy and the load is also large. All of the above will make the tracks easy to be damaged, and the maintenance of the tracks is also inconvenient and costly. Summary of the Invention

[0006] To overcome the aforementioned shortcomings, the present invention aims to provide a helical spring heat treatment furnace and heat treatment method. The furnace utilizes the rotation of rollers to drive the helical springs to rotate, ensuring uniform heating and improving thermal efficiency. Simultaneously, a horizontal bar lifting conveying method is used to transport the helical springs backward. The furnace can be controlled by PLC, making it easy to operate, highly intelligent, reducing equipment damage rate, facilitating replacement, and requiring a small footprint.

[0007] The technical solution adopted by the present invention to solve its technical problem is as follows: a helical spring heat treatment furnace, including a furnace body, rollers, a main controller, and a first lifting assembly. A natural gas nozzle is provided at the top of the furnace body. Multiple parallel rollers are provided in the furnace body. The end shaft sections at both ends of each roller are assembled on the furnace body through bearings. A crossbar is provided between adjacent rollers in the furnace body. The two ends of the crossbar are respectively fixed on an independent first lifting assembly. The first lifting assembly drives the crossbar to rise and fall. The end shaft section at one end of the roller is mechanically connected to a drive motor through a transmission mechanism. A feed port and a discharge port are respectively provided at both ends of the furnace body. Conveyor belts are provided outside the feed port and the discharge port. A feeding mechanism is provided at the feed port.

[0008] Specifically, the furnace body includes two side walls, a front wall, a front side wall, and a top plate. The front wall has a feed inlet, and the front side wall has a discharge outlet. The front wall, front side wall, top plate, and side walls include an outer layer and an inner heat insulation layer.

[0009] Specifically, a protective wall is provided outside the side wall, and the cavity between the side wall and the protective wall is the equipment cavity.

[0010] Specifically, a lifting slot is provided on the side wall at the position corresponding to the crossbar. The lifting slot is vertically arranged, and the crossbar passes through the lifting slot and is assembled on the first lifting assembly. The first lifting assembly is located on the outside of the side wall.

[0011] Specifically, the crossbar is equipped with a lever, which is obliquely positioned with its upper edge facing the feed inlet.

[0012] Specifically, the distance between the crossbar and its adjacent roller near the feed inlet is less than the distance between the crossbar and its adjacent roller near the discharge outlet.

[0013] Specifically, the outer surface of the roller shaft is provided with an anti-slip structure.

[0014] Specifically, the feeding mechanism includes a push plate and a push rod. The push plate is located on the side of the conveyor belt away from the furnace body, and the telescopic end of the push rod is fixedly connected to the push plate.

[0015] Specifically, both the feed inlet and the discharge outlet are equipped with furnace doors, which are connected to the second lifting assembly.

[0016] Specifically, it also includes a discharge limiting plate, which is located on the side of the conveyor belt at the discharge port that is away from the furnace body.

[0017] Specifically, the roller is made of heat-resistant stainless steel and has a hollow structure.

[0018] Specifically, the bottom of the furnace body is lined with a layer of refractory bricks to reduce heat loss.

[0019] Specifically, the first lifting assembly, the second lifting assembly, and the push rod are electric push rods or hydraulic rods.

[0020] Specifically, a heat-insulating baffle is provided at the lifting slot hole, and a sleeve hole is provided on the heat-insulating baffle. The two ends of the crossbar are sleeved in the sleeve hole. Limiting grooves are provided on both sides of the lifting slot hole, and the two sides of the heat-insulating baffle are located in the limiting grooves.

[0021] A heat treatment method for a helical spring includes the following steps:

[0022] S1 feed

[0023] The furnace door at the feed inlet is raised, and the feeding mechanism pushes the spiral spring on the conveyor belt into the furnace body, placing it in the gap between the first roller shaft and the second roller shaft counting from the front of the furnace body;

[0024] S2 segmented heat treatment

[0025] When the corresponding first lifting component is lowered to the lowest position, it will not touch the helical spring. The helical spring is above the two adjacent rollers and rotates under the action of the rollers' self-rotation, so that the heat treatment of the surface of the helical spring is carried out evenly.

[0026] S3 transports to the back end

[0027] The first lifting assembly rises to a certain height, the crossbar is raised, the paddle is raised on the front side, the spiral spring is raised upward and rolled backward into the gap between the rear rollers;

[0028] S4. Repeat steps S2 and S3 until the helical spring completes the heat treatment process in the last roller gap.

[0029] S4, Discharge

[0030] After the helical spring has been heat-treated, lift the crossbar near the discharge port and roll the helical spring above it out of the furnace body and onto the conveyor belt at the discharge port to exit this process and enter the next process.

[0031] The present invention has the following beneficial effects: During the rotation of the roller, the helical spring workpiece rotates, making it heated evenly in the heat treatment furnace. By controlling the rotation time of the helical spring between the two rollers, the requirements of different heat treatment durations can be met, making the product performance more uniform. The furnace body does not need to be equipped with additional pits or other devices, reducing the floor space. The lifting and lowering of the crossbar is controlled separately by the first lifting component, which is used to push the helical spring backward, realizing the function of transporting the helical spring backward. The transport rhythm can be set. By controlling the time difference when the helical spring enters the furnace, it can be sent out of the furnace body in sequence when exiting the furnace, completing the heat treatment process and entering the next process. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention.

[0033] Figure 2 This is a schematic diagram of the front structure of the present invention.

[0034] Figure 3 This is a schematic diagram of the AA-direction structure of the present invention.

[0035] Figure 4 This is a schematic diagram of the internal structure of the furnace body of the present invention.

[0036] Figure 5 This is a top view of the furnace body structure of the present invention.

[0037] Figure 6 This is a schematic diagram of the internal structure of the furnace body of the present invention from another perspective.

[0038] Figure 7 This is an enlarged schematic diagram of the structure at point A of the present invention.

[0039] Figure 8 This is a schematic cross-sectional view of the roller shaft of the present invention.

[0040] Figure 9 This is a schematic diagram of the lifting rod structure of the present invention.

[0041] Figure 10 This is a schematic diagram of the BB-direction structure of the present invention.

[0042] Figure 11 This is a control principle diagram of the present invention.

[0043] Figure 12 This is a cross-sectional schematic diagram of each sidewall of the present invention.

[0044] Figure 13 This is a schematic diagram of the structure at the lifting slot hole in another embodiment of the present invention.

[0045] Figure 14 This is a schematic diagram of the structure of the helical spring of the present invention located on the roller shaft.

[0046] The diagram shows: 1. Furnace body, 101. First side wall, 102. Top plate, 103. Second side wall, 104. Front wall, 105. Front side wall, 106. First protective wall, 107. Second protective wall, 2. Conveyor belt, 3. Feeding mechanism, 301. Push plate, 302. Push rod, 4. Furnace door, 401. Second lifting assembly, 402. First limiter, 5. Roller shaft, 501. First driven sprocket, 502. Second driven sprocket, 503. Bearing, 504. Anti-slip protrusion, 6. Crossbar, 601. First lifting assembly, 602. Paddle, 7. Refractory brick layer, 8. Drive motor, 801. First chain, 802. Second chain, 9. Discharge limit plate, 10. Lifting slot, 1001. Limiting slide, 11. Insulation baffle, 1101. Sleeve hole, 12. Natural gas nozzle. Detailed Implementation

[0047] The invention will now be described in further detail with reference to the accompanying drawings.

[0048] like Figures 1 to 12 The helical spring heat treatment furnace shown includes a furnace body 1, rollers 5, a main controller, and a first lifting assembly. A natural gas nozzle 12 is installed at the top of the furnace body 1. Multiple parallel rollers 5 are installed inside the furnace body 1. The end sections of each roller 5 are mounted to the furnace body via bearings. A crossbar 6 is installed between adjacent rollers 5 inside the furnace body 1. The two ends of the crossbar 6 are fixed to an independent first lifting assembly 601. The first lifting assembly 601 drives the crossbar 6 to rise and fall. One end section of each roller 5 is mechanically connected to a drive motor 8 via a transmission mechanism. The furnace body 1 is provided with a feed inlet and a discharge outlet at both ends. Conveyor belts 2 are provided outside both the feed inlet and the discharge outlet. A feeding mechanism 3 is provided at the feed inlet. When feeding, the conveyor belt 2 outside the feed inlet is higher than the roller 5 closest to the feed inlet inside the furnace, which makes it easier for the feeding mechanism to push the helical spring on the corresponding conveyor belt 2 into the furnace body 1. When discharging, the conveyor belt 2 at the discharge outlet is lower than the roller 5 closest to the discharge outlet inside the furnace body 1. The first crossbar 6 from the discharge outlet is lifted, giving an upward force to the helical spring above it, so that the processed helical spring rolls out of the furnace body 1.

[0049] Specifically, the furnace body 1 includes two side walls, a front wall 104, a front side wall 105, and a top plate 102. The front wall 104 has a feed inlet, and the front side wall 105 has a discharge outlet. The lower surface of the top plate 101 is evenly provided with a plurality of nozzles 12. The front wall 104, the front side wall 105, the top plate 102, and the side walls include an outer layer 1A and an inner heat insulation layer 1B.

[0050] Specifically, the sidewalls are divided into a first sidewall 101 and a second sidewall 103. The first sidewall 101 is provided with a first protective wall 106, and the second sidewall 103 is provided with a second protective wall 107. The cavity between the first sidewall 101 and the first protective wall 106, and the cavity between the second sidewall 103 and the second protective wall 107 are equipment cavities. The end shaft section of the roller shaft 5 passes through the bearings 503 on the first sidewall 101 and the second sidewall 103, and is exposed on the outside of the first sidewall 101 and the second sidewall 103. It is connected to the drive motor 8 through a transmission mechanism, and the drive motor 8 drives the roller shaft 5 to rotate. The first lifting assembly 601, the transmission mechanism, and the drive motor 8 are arranged inside the equipment cavity. The first sidewall 101 and the second sidewall 103 serve to insulate and protect the first lifting assembly and the drive motor 8. The first protective wall 106 and the second protective wall 107 can protect the equipment from external dust and other influences, ensure its normal operation, and protect the safety of external workers.

[0051] Specifically, a lifting slot 10 is provided on the side wall at the position corresponding to the crossbar 6. The lifting slot 10 is vertically arranged. The crossbar 6 passes through the lifting slot 10 and is assembled on the first lifting assembly 601. The first lifting assembly 601 is located on the outside of the side wall.

[0052] Specifically, the crossbar 6 is provided with a lever 602, which is obliquely arranged with its upper edge facing the feed inlet side and forming an angle of 30-50 degrees with the horizontal plane, with the optimal angle being 45 degrees.

[0053] Specifically, the distance relationship between the crossbar 6 and the two adjacent rollers 5 is such that the distance between the crossbar 5 and the roller 5 near the feed inlet is less than the distance between the crossbar 6 and the roller 5 near the discharge outlet. The optimal position is 1 / 3 of the distance between the two rollers from the front end.

[0054] Specifically, the outer surface of the roller 5 is provided with an anti-slip structure, which includes anti-slip protrusions 504, anti-slip grooves, etc. The anti-slip protrusions and anti-slip grooves are arranged along the axial direction of the roller 5, which can effectively rotate the helical spring by rotating the roller 5 itself, making the heat treatment more uniform.

[0055] Specifically, the feeding mechanism 3 includes a push plate 301 and a push rod 302. The push plate 301 is located on the side of the conveyor belt 2 away from the furnace body 1. The telescopic end of the push rod 302 is fixedly connected to the push plate 301. During the feeding process of the feeding conveyor belt 2, the helical spring is located on the conveyor belt 2 and is sequentially conveyed to the rear end. When it reaches the predetermined position, the feeding stops and waits to enter the furnace body 1.

[0056] Specifically, both the feed inlet and the discharge outlet are equipped with furnace doors 4. The furnace doors 4 are connected to the second lifting assembly 401. The second lifting assembly 401 has its own control system connected to the main controller. It lifts and lowers according to the parameters set by the main controller. The second lifting assembly 401 drives the furnace door 4 to lift and lower, realizing the opening and closing of the feed inlet and the discharge outlet. This prevents heat loss during the heat treatment process and reduces production costs. The outer layer of the furnace door 4 is made of sheet iron, and the inside is made of refractory cotton, making the furnace door 4 both heat-insulating and lightweight. When the second lifting assembly 401 malfunctions, the furnace door 4 will automatically stop lifting and lowering when it reaches the position set by the first limit switch 402.

[0057] Specifically, it also includes a discharge limiting plate 9, which is located on the side of the discharge port conveyor belt 2 away from the furnace body 1 to prevent the spiral spring of the furnace body 1 from rolling off and to transport it to the next process on the conveyor belt 2.

[0058] Specifically, the roller 5 is made of heat-resistant stainless steel and has a hollow structure, which reduces its manufacturing cost and weight, reduces the working intensity of the corresponding first lifting component 601, and reduces energy consumption.

[0059] Specifically, a layer of refractory bricks 7 is laid at the bottom of the furnace body 1 to reduce heat loss.

[0060] Specifically, the first lifting assembly 601, the second lifting assembly 401, and the push rod 302 are preferably electric push rods, but hydraulic rods and lifting assemblies can also be used. The first lifting assembly 601, the second lifting assembly 401, and the push rod 302 have their own control systems connected to the main controller, and extend and retract according to the parameters set by the main controller. The furnace door is equipped with first limiters 402 at both the top and bottom, and each crossbar 6 inside the furnace is equipped with a second limiter. The first and second limiters 402 are connected to the main controller, and can provide an emergency stop when the control system of the first lifting assembly 601, the second lifting assembly 401, and the push rod 302 cannot control their extension and retraction. The main controller is connected to each drive motor, controlling the rotation speed of the drive motor 8. Figure 11 As shown, assuming there are m rollers, there are (m-1) crossbars, and the corresponding first lifting components 601 have 2*(m-1) units. The main controller needs to connect the corresponding number of first lifting components 601, second lifting components 401, push rods 302, first limiters, and second limiters 402. This part is the prior art. The specific controller and corresponding drive circuit are selected according to the actual situation, and will not be elaborated here.

[0061] Specifically, the transmission mechanism includes a driving sprocket and a driven sprocket. One end of the roller shaft 5 is equipped with a driven sprocket. The driving sprocket is mounted on the output end of the drive motor 8. A first chain 801 is sleeved around the driving sprocket and the driven sprocket. The driven sprockets are connected in series via a second chain 802. The drive motor 8 drives the roller shaft to rotate. To effectively connect multiple roller shafts 5 in series, each roller shaft 5 is equipped with two driven sprockets: a first driven sprocket 501 and a second driven sprocket 502. The first driven sprocket 501 and the second driven sprocket 502 can be located at the same end of the roller shaft 5 or at opposite ends. The second chain 802 divides the roller shaft into multiple groups, and adjacent roller shafts 5 are connected and driven by the second chain 802. Figure 5 As shown, the first driven sprocket 501 of the first roller shaft 5 is connected to the driving sprocket via the first chain 801. The second driven sprocket 502 of the first roller shaft 5 is connected to the second driven sprocket 502 of the adjacent second roller shaft 5 via the second chain 802. The first driven sprocket of the second roller shaft 5 is connected to the first driven sprocket 501 of the third roller shaft 5 via the second chain 802, and so on, until the last roller shaft, to achieve synchronous driving of each roller shaft and drive motor 8.

[0062] Example 2

[0063] In order to achieve a heat preservation effect, such as Figure 13 As shown, a heat-insulating baffle 11 is provided at the lifting slot hole 10. The heat-insulating baffle 11 is provided with a sleeve hole 1101. The two ends of the crossbar 6 are sleeved in the sleeve hole 1101. Limiting slide grooves 1001 are provided on both sides of the lifting slot hole 10. The two sides of the heat-insulating baffle 11 are located in the limiting slide grooves 1001 and move up and down along the limiting slide grooves 1001.

[0064] A heat treatment method for a helical spring includes the following steps:

[0065] S1 feed

[0066] The furnace door 2 at the feed inlet is raised, and the push rod 301 pushes the push plate 301, pushing the helical spring on the conveyor belt 2 into the furnace body 1, where it is located in the first roller gap 1401 between the first roller 5 and the second roller 5 from the front end of the furnace body 1. The furnace door 4 is raised to a height slightly higher than the height of the upper edge of the helical spring 13, and the helical spring 13 enters the furnace body 1, located in the first roller gap 1401 between the first roller 5 and the second roller 5.

[0067] S2 segmented heat treatment

[0068] The corresponding first lifting component 601 is lowered to its lowest position, so it will not touch the helical spring 13. The helical spring 13 is located above the two adjacent rollers 5 and rotates under the self-rotation of the rollers 5, ensuring that the surface heat treatment of the helical spring 13 is carried out evenly. Figure 14 As shown;

[0069] S3 transports to the rear.

[0070] The first lifting assembly 601 is raised to a certain height, the crossbar 6 is raised, the paddle 602 is raised to the front side, and the spiral spring 13 is raised upward. Under this lifting force, it rolls backward and rolls into the second roller gap 1402 between the second roller shaft 5 and the third roller shaft 5.

[0071] S4. Repeat steps S2 and S3 until the helical spring 13 is in the last roller gap, and the heat treatment process is completed.

[0072] S5, Discharge

[0073] After the helical spring has been heat-treated, lift the crossbar 6 near the discharge port and roll the helical spring 13 above it out of the furnace body 1 and onto the conveyor belt 2 at the discharge port to exit this process and enter the next process.

[0074] Each batch of helical springs enters the furnace sequentially, and steps S1-S4 are repeated. The rotation speed of the rollers is controlled, and the lifting time of the corresponding crossbar 6 is controlled. The springs are then conveyed to the discharge port in sequence, thereby controlling the heat treatment time of the helical springs in the furnace.

[0075] This invention is not limited to the described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0076] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A helical spring heat treatment furnace, comprising a furnace body, rollers, a main controller, and a first lifting assembly, wherein a natural gas nozzle is disposed at the top of the furnace body, characterized in that: The furnace body is equipped with multiple parallel rollers. The end shaft sections at both ends of each roller are mounted on the furnace body via bearings. A crossbar is provided between adjacent rollers in the furnace body. The two ends of the crossbar are fixed to an independent first lifting assembly. The first lifting assembly drives the crossbar to rise and fall. The end shaft section at one end of the roller is mechanically connected to the drive motor through a transmission mechanism. The furnace body is provided with a feed inlet and a discharge outlet at both ends. Conveyor belts are provided outside the feed inlet and the discharge outlet. A feeding mechanism is provided at the feed inlet. The crossbar is equipped with a paddle, which is obliquely positioned with its upper edge facing the feed inlet. The distance between the crossbar and its adjacent roller near the feed inlet is less than the distance between the crossbar and its adjacent roller near the discharge outlet.

2. The helical spring heat treatment furnace according to claim 1, characterized in that: The furnace body includes two side walls, a front wall, a front side wall, and a top plate. The front wall has a feed inlet, and the front side wall has a discharge outlet. The front wall, front side wall, top plate, and side walls include an outer layer and an inner insulation layer.

3. A helical spring heat treatment furnace according to claim 2, characterized in that: The sidewall is provided with a protective wall, and the cavity between the sidewall and the protective wall is the equipment cavity.

4. A helical spring heat treatment furnace according to claim 2 or 3, characterized in that: A lifting slot is provided on the side wall at the position corresponding to the crossbar. The lifting slot is set vertically. The crossbar passes through the lifting slot and is assembled on the first lifting assembly. The first lifting assembly is located on the outside of the side wall.

5. A helical spring heat treatment furnace according to claim 1, characterized in that: The outer surface of the roller is provided with an anti-slip structure.

6. A helical spring heat treatment furnace according to claim 1, characterized in that: The feeding mechanism includes a push plate and a push rod. The push plate is located on the side of the conveyor belt away from the furnace body, and the telescopic end of the push rod is fixedly connected to the push plate.

7. A helical spring heat treatment furnace according to claim 1, characterized in that: The bottom of the furnace body is covered with a layer of refractory bricks.

8. A helical spring heat treatment furnace according to claim 4, characterized in that: A heat-insulating baffle is provided at the lifting slot hole, and a sleeve hole is provided on the heat-insulating baffle. The two ends of the crossbar are sleeved in the sleeve hole. Limiting grooves are provided on both sides of the lifting slot hole, and the two sides of the heat-insulating baffle are located in the limiting grooves.

9. A heat treatment method for helical springs, using the helical spring heat treatment furnace according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1 feed The furnace door at the feed inlet is raised, and the feeding mechanism pushes the spiral spring on the conveyor belt into the furnace body, placing it in the gap between the first roller shaft and the second roller shaft counting from the front of the furnace body; S2 segmented heat treatment When the corresponding first lifting component is lowered to the lowest position, it will not touch the helical spring. The helical spring is above the two adjacent rollers and rotates under the action of the rollers' self-rotation, so that the heat treatment of the surface of the helical spring is carried out evenly. S3 transports to the back end The first lifting assembly rises to a certain height, the crossbar is raised, the paddle is raised on the front side, the spiral spring is raised upward and rolled backward into the gap between the rear rollers; S4. Repeat steps S2 and S3 until the helical spring completes the heat treatment process in the last roller gap. S4, Discharge After the helical spring has been heat-treated, lift the crossbar near the discharge port and roll the helical spring above it out of the furnace body and onto the conveyor belt at the discharge port to exit this process and enter the next process.

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