Nitriding treatment tool and using method

Abstract

A nitriding treatment tool belongs to the technical field of mechanical equipment and comprises a plurality of framework groups, a plurality of height adjusting parts and a plurality of connecting parts, each framework group comprises an upper framework, a lower framework, a plurality of connecting blocks and a placing net, the connecting blocks are positioned between the two frameworks and are fixedly connected with the frameworks, and the placing net is fixedly mounted in the frameworks. The frame sets are sequentially arranged from top to bottom, the connecting parts are fixedly connected with the frame sets, the height adjusting parts are located between every two vertically-adjacent frame sets and detachably connected with the connecting parts, the engine valve nitriding device is suitable for nitriding of engine valves, and the distance between the frames and the hole diameter of a containing net can be adjusted according to the sizes of other shaft parts and rod parts; the tool is suitable for nitriding machining of various parts, and the universality of the tool is improved; meanwhile, the number of the frame groups can be flexibly increased or decreased, small-batch multi-specification production can be met, large-batch centralized machining can be adapted, and the production flexibility and the large-scale requirement are both considered.

Description

Technical Field

[0001] This invention belongs to the field of mechanical equipment technology, specifically relating to a nitriding treatment tool and its usage method. Background Technology

[0002] With the development of the automotive industry and the continuous progress of engine research and development, the requirements for valve operation are becoming increasingly stringent. The surface treatment of valves has also changed from the fine grinding of the outer diameter without nitriding or chrome plating to nitriding or chrome plating. Due to the environmental impact of the chrome plating process, the proportion of nitrided valves is also increasing, and the surface quality requirements for the nitriding process are becoming increasingly stringent. At the same time, there is also great potential for improvement in production costs.

[0003] Traditional tooling uses a single-layer plate structure design, with the valve supported by only a flat plate frame. Due to structural limitations, the valves can only be stacked closely together, resulting in very small gaps between the valves. During the nitriding process, the gas and liquid cannot flow smoothly, which not only causes uneven nitriding layer thickness, but also makes it easy to deform due to stacking, seriously affecting product quality. At the same time, the plate frame and the valve have a large-area circular contact, and nitriding layer defects are prone to occur at the contact area, which damages the appearance integrity of the valve.

[0004] In addition, traditional single-layer plate tooling has many practical drawbacks: First, the plate structure is relatively heavy, requiring more heat to be consumed during heating, thus increasing energy costs; second, the plate frame is prone to generating significant thermal stress during the heating and cooling thermal cycle, which can easily lead to deformation and cracking after long-term use, resulting in a shorter service life and increased tooling replacement costs; third, the single-layer structure has extremely poor adaptability, making it impossible to adjust the load-bearing space according to valve specifications, and the processing capacity per operation is limited, resulting in low production efficiency; and it has shortcomings in the production process. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a nitriding treatment tool and its usage method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a nitriding treatment fixture, comprising an array frame group, an array height adjustment part, and an array connecting part. The frame group consists of two upper and lower frames, several connecting blocks, and a placement net. The connecting blocks are located between the two frames and are fixedly connected to the frames. The placement net is fixedly installed inside the frames. The array frame groups are arranged sequentially from top to bottom. The connecting part is fixedly connected to the frame group. The height adjustment part is located between two adjacent upper and lower frame groups and is detachably connected to the connecting part.

[0007] Preferably, the connecting part includes a vertical block, a slot is provided on the end face of the vertical block away from the frame, the end face of the vertical block close to the frame is fixedly connected to the frame, and a first screw hole is provided on one side of the vertical block.

[0008] Preferably, the height adjustment part includes a first connecting component, a second connecting component, an adjusting component, and a locking component. The first connecting component is fixedly connected to the adjusting component, and the second connecting component is detachably connected to the adjusting component. The second connecting component, the adjusting component, and the first connecting component are arranged sequentially from top to bottom, and the vertical block is locked to the first connecting component or the second connecting component by the locking component.

[0009] Preferably, the first connecting component includes a first support block, a first groove is formed at the bottom end of the first support block, a first limiting block is fixedly installed on the inner wall of the top end of the first groove, the vertical block can be inserted into the first groove, the first limiting block can be inserted into the slot, and a second screw hole is formed on one side of the first support block and one side of the first limiting block.

[0010] Preferably, the second connecting component includes a second support block, a second groove is formed at the top of the second support block, a second limiting block is fixedly installed on the inner wall of the bottom end of the second groove, the vertical block can be inserted into the second groove, the second limiting block can be inserted into the slot, and a third screw hole is formed on one side of the second support block and one side of the second limiting block.

[0011] Preferably, the adjusting component includes a threaded rod, the bottom end of which is fixedly installed on the top end of the first support block. An adjusting nut is threadedly fitted onto the threaded rod. A blind hole is opened at the bottom end of the second support block. A threaded sleeve is installed in the blind hole with a bearing. The bottom end of the threaded sleeve is open, and an internal thread is opened on the inner wall of the threaded sleeve. The top end of the threaded rod is inserted into the threaded sleeve and threadedly fitted with the internal thread. The top end of the adjusting nut is fixedly connected to the bottom end of the threaded sleeve.

[0012] Preferably, the locking element includes a bolt that can pass through a first screw hole and a second screw hole or a first screw hole and a third screw hole.

[0013] Preferably, the top surface of the frame has several through holes, and a vertical rod is fitted into the several through holes located on the same vertical center line. A ring is fixedly installed at the top of the vertical rod, and a screw is fixedly installed at the bottom of the vertical rod. A nut is threaded onto the screw.

[0014] Preferably, the frame, connecting block, placement net, vertical block, first support block, second support block, first limiting block, and second limiting block are all made of stainless steel.

[0015] A method for using a nitriding treatment fixture, comprising the following steps: S1. Preparation before use: S11. Tooling Condition Inspection: Inspect the integrity of the frame assembly, connecting parts, height adjustment parts, and vertical rods, confirming no deformation, cracks, or weld detachment; ensure the mesh is undamaged and the wires are not loose; check the threaded connections for rust or stripping; rotate the adjusting nut of the height adjustment part to verify the smooth movement of the second support block along the threaded rod; check the smoothness of the locking part's fit with the screw hole and the insertion / removal fit of the vertical block and support block; use compressed air to remove debris from the tooling surface; if oil stains or nitriding residues are present, wipe clean with a high-temperature resistant cleaner. S12. Preparation of supporting equipment and tools: Prepare lifting equipment with a load-bearing capacity greater than the total weight of the tooling and engine valves, check the integrity of the hooks and wire ropes, and equip with wrenches that are compatible with bolts and adjusting nuts, as well as high-temperature resistant non-slip gloves and protective glasses; check the normality of the nitriding furnace temperature control system, ammonia supply system and exhaust system, ensure that the furnace is clean and the furnace door is well sealed, and preheat the nitriding furnace; S13. Engine valve preparation: Remove oxide scale, oil stains and burrs from the valve surface, and classify them according to diameter and height specifications after cleaning and drying; S2. Tooling assembly and spacing adjustment: S21. Basic frame assembly operation: Determine the number of frame assemblies needed based on the number and height of the valves. Place the bottom frame assembly on a flat platform. If multiple frame assemblies need to be assembled, select one of the following two spacing adjustment methods: Method 1: Dynamic Adjustment S21a1. First, insert the vertical block on the top surface of the lower frame assembly into the first groove of the first support block, so that the first limiting block is embedded in the slot and the first screw hole is aligned with the second screw hole, and fix the height adjustment part to the lower frame assembly with bolts; S21a2. Rotate the adjusting nut to move the second support block up and down along the threaded rod until the distance between the top surface of the second support block and the mesh placed in the lower frame group is 5-10mm larger than the valve height; S21a3. Insert the vertical block on the bottom surface of the upper frame assembly into the second groove of the second support block, so that the second limiting block is embedded in the slot and the first screw hole is aligned with the third screw hole, and fix the upper frame assembly and the height adjustment part with bolts; Method 2: Preset Adjustment S21b1. First, place the height adjustment unit independently, and rotate the adjusting nut so that the distance between the first support block and the second support block is 5-10mm larger than the valve height to complete the spacing preset; S21b2. Insert the vertical block on the top surface of the lower frame assembly 1 into the first groove of the first support block, so that the first limiting block is embedded in the slot and the first screw hole is aligned with the second screw hole, and fix the height adjustment part to the lower frame assembly with bolts; S21b3. Insert the vertical block on the bottom surface of the upper frame assembly into the second groove of the second support block, so that the second limiting block is embedded in the slot and the first screw hole is aligned with the third screw hole, and fix the upper frame assembly and the height adjustment part with bolts; S22. Multiple expansion and horizontal calibration: If three or more frame groups need to be assembled, repeat any of the adjustment methods in S21 and stack the frame groups in sequence; after assembling each group, use a level to check the flatness of all frame groups to ensure that there is no tilt, and recheck the tightness of all bolts; S23. Vertical rod installation and fixing: Insert the vertical rod through the through hole of the uppermost frame group, and then through the through holes of all the lower frame groups in sequence. Screw the nut into the screw at the bottom of the vertical rod so that the nut fits tightly against the bottom surface of the lowermost frame group to achieve overall fixing. S3. Engine valve placement: S31. Place the valves into the mesh of the placement net in an alternating manner, ensuring that the axes of adjacent valves do not coincide, the bottom of the valves are in contact with the placement net at four points, and the gap between valves is not less than 5mm; the valves in the same layer are evenly distributed, and are placed gently without exceeding the edge of the frame. S32. Visually inspect whether the valves are stable and not stacked, and ensure that there is at least 3mm of space between the top of the valve and the placement net of the upper frame assembly. Check whether the placement net is dented or deformed due to the load. S4. Tooling hoisting and nitriding furnace operation: S41. The operator, wearing protective gear, hooks the hook of the hoisting equipment onto the ring at the top of the vertical rod, and adjusts the position of the hook so that the center of gravity of the fixture coincides with the center line of the hook; slowly lift the fixture to 10-20cm off the ground and then pause, letting it stand for 30 seconds to observe the balance of the fixture, and check whether the connection parts are loose or the valves are displaced; after confirming that there are no abnormalities, move the hoisting equipment smoothly and slowly send the fixture into the nitriding furnace, ensuring that the distance between the fixture and the furnace wall is not less than 50mm, and after lowering it into the furnace support, slowly separate the hook and remove it from the hoisting equipment; S42. Close the nitriding furnace door and check the sealing performance. Set the nitriding process parameters according to the valve material. Start the temperature control system and gas supply system. Record the furnace temperature and ammonia pressure every 30 minutes during the nitriding process. If the temperature fluctuation exceeds ±5℃ or the ammonia pressure is abnormal, stop the operation immediately and troubleshoot the fault. S5. Post-nitriding treatment and tooling maintenance: S51. After nitriding is completed, shut off the ammonia supply system and keep the exhaust system running for 30 minutes. After the residual ammonia in the furnace is discharged, stop the exhaust system. After the furnace temperature drops naturally to below 200℃, open the furnace door and use hoisting equipment to lift the tooling out and place it on a ventilated and dry cooling platform to cool naturally to room temperature. After cooling, first unscrew the nut at the bottom of the vertical rod and take out the vertical rod. Then, disassemble the bolts connecting the height adjustment part and the vertical block, disassemble each frame assembly, and take out the valves one by one and put them into the special storage box. S52. Tooling Cleaning and Maintenance: Use a wire brush to remove nitride powder adhering to the tooling surface. For stubborn residues, use a high-pressure water gun with a temperature not exceeding 80℃ to rinse. After rinsing, wipe dry with a cotton cloth and place in a ventilated area to air dry. Check the thread condition of bolts and adjusting nuts. For rusted areas, polish with fine sandpaper and apply high-temperature resistant grease. For slightly deformed placement nets, use a special clamp to level and restore them. If the placement net has broken wires or deformed mesh, replace it with a new placement net. For height adjustment parts that are stuck during rotation, disassemble the threaded sleeve and bearing, clean internal impurities, apply high-temperature grease, and reassemble. S6. Tooling storage: Stack the frame assembly flat, and classify small parts such as vertical rods, bolts, and adjusting nuts into separate toolboxes; keep the storage environment dry and ventilated, and avoid direct sunlight; inspect the stored tooling parts every 3 months, remove rust from rusted parts in time, and repair or replace deformed parts.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: (1) Improve the quality of engine valve nitriding: The tooling adopts a layered frame design, with a placement mesh inside the frame, which allows the engine valves to be placed in an alternating manner without stacking, greatly increasing the gap between the valves. This design not only facilitates the uniform flow of gas and liquid during nitriding, ensuring that the nitrided layer on the valve surface is uniform and of consistent thickness, but also effectively reduces the deformation of the valves caused by stacking, improving the dimensional accuracy of the product; at the same time, the placement mesh and the valve only have four points of contact (not circular contact), avoiding abnormal thickness of the nitrided layer or appearance defects at the contact points, improving the appearance quality of the nitrided product and reducing the defect rate; (2) Reduce processing energy consumption and tooling wear: Compared with traditional plate frames, the structural design of the placement mesh greatly reduces the weight of the tooling itself, which reduces energy consumption during hoisting and heat consumption during nitriding furnace heating, thus achieving energy saving and consumption reduction; In addition, the placement mesh generates less thermal stress during heating and cooling, and is less prone to deformation or breakage due to thermal expansion and contraction, which significantly extends the service life of the tooling and reduces tooling replacement costs. (3) Flexible height adjustment and strong adaptability: The distance between adjacent upper and lower frame groups can be precisely adjusted through the threaded rod, threaded sleeve, adjusting nut and other components of the height adjustment part. It can not only adapt to engine valves of different lengths and specifications, avoiding placement restrictions caused by valve size differences, but also adjust the spacing between valves according to the requirements of nitriding process to optimize gas flow effect. At the same time, the height adjustment part and the connecting part are detachable, which makes it easy to increase or decrease the number of frame groups according to production needs, realize the simultaneous processing of multiple valve groups, and improve production efficiency. (4) Easy and efficient disassembly and disassembly: The connecting part (vertical block) and the height adjustment part (first and second support blocks) of the tooling are positioned and matched by slots and limiting blocks, and then locked and fixed by bolts. The positioning is accurate and the disassembly and assembly are simple. The frame assembly can be spliced ​​and disassembled without complicated tools. The grooves and limiting blocks of the vertical blocks and support blocks at the four corners of the frame assembly form a double positioning to ensure the structural accuracy after connection and avoid assembly deviation from affecting valve placement. In addition, the design of the vertical rod and through hole can further lock the multi-layer frame assembly to prevent the frame from shifting during hoisting or nitriding. At the same time, the ring at the top of the vertical rod makes it easy to hoist the tooling into and out of the nitriding furnace, simplifying the operation process. (5) Stable and reliable structure with high safety: The frame assembly uses four connecting blocks to fix the upper and lower frames, and connects with the vertical blocks at the four corners and the height adjustment part to form a symmetrical and stable support structure, ensuring that the overall rigidity of the multi-layer frame assembly is sufficient and not easily deformed after splicing; the height adjustment part realizes distance adjustment through threaded engagement, and the structure has strong self-locking after adjustment, and the connection is further improved by bolt locking; the locking design of the vertical rod and nut further strengthens the overall constraint of the multi-layer frame, avoids the frame from loosening or shifting during hoisting or nitriding, improves the safety of the production process, and prevents product damage or safety hazards caused by unstable tooling; (6) Strong versatility and good expandability: The modular design of the tooling (the frame assembly, connecting part and height adjustment part can be independently separated) is not only suitable for the nitriding treatment of engine valves, but also allows for the adjustment of frame spacing and mesh size according to the dimensions of other shaft and rod parts, adapting to the nitriding processing of various parts and improving the versatility of the tooling; at the same time, the number of frame assemblies can be flexibly increased or decreased, which can meet the needs of small-batch multi-specification production and also adapt to large-batch centralized processing, taking into account both production flexibility and scale requirements. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram showing the installation status of the height adjustment unit and the frame assembly; Figure 3 This is a diagram showing the height adjustment unit and frame assembly in their uninstalled state. Figure 1 ; Figure 4 This is a diagram showing the height adjustment unit and frame assembly in their uninstalled state. Figure 2 ; Figure 5 This is an enlarged schematic diagram of the internal structure of the height adjustment unit; Figure 6 This is a schematic diagram of the internal structure of the connecting part; Figure 7 This is a structural diagram of the vertical rod; Explanation of reference numerals in the attached figures: 1. Frame assembly; 101. Frame; 102. Connecting block; 2. Vertical block; 3. Slot; 4. First screw hole; 5. First support block; 6. First groove; 7. First limiting block; 8. Second screw hole; 9. Second support block; 10. Second groove; 11. Second limiting block; 12. Third screw hole; 13. Threaded rod; 14. Adjusting nut; 15. Blind hole; 16. Threaded sleeve; 17. Through hole; 18. Vertical rod. Detailed Implementation

[0018] To better understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0020] Example 1 The following is combined Figures 1-7 A further description of a nitriding treatment fixture in Example 1 is provided, such as... Figure 1 As shown, the array includes an array frame group 1, an array height adjustment part, and an array connecting part. The frame group 1 consists of two upper and lower frames 101, several connecting blocks 102, and a placement net. The connecting blocks 102 are located between the two frames 101 and are fixedly connected to the frames 101. The placement net is fixedly installed inside the frames 101. The array frame groups 1 are arranged sequentially from top to bottom. The connecting part is fixedly connected to the frame group. The height adjustment part is located between two adjacent sets of frame groups 1 and is detachably connected to the connecting part.

[0021] The bottom surface of connecting block 102 is fixedly connected to one corner of the top surface of the lower frame 101, and the top surface of connecting block 102 is fixedly connected to one corner of the bottom surface of the upper frame 101. There are at least four connecting blocks 102. This application only shows two adjacent frame groups 1. The frame groups 1 are overlapped from bottom to top, and the height adjustment part and the connecting part are installed between the adjacent upper and lower frame groups 1 to form a tooling frame. Then, the engine valves are arranged alternately according to the mesh of the placement net. After the engine valves are arranged, the tooling frame is hoisted into the nitriding furnace for further processing. After nitriding, the tooling frame is lifted out of the nitriding furnace for subsequent processes. The double-layer frame and placement mesh increase the gap between the engine valves, which is beneficial for the flow of gas and liquid between the valves. The engine valves are no longer stacked, reducing deformation and improving quality. Compared with a plate frame, the placement mesh reduces weight and heat consumption. At the same time, the placement mesh has less thermal stress during heating and cooling, increasing its service life. Moreover, when the engine valve contacts the placement mesh, there are only four points, not a circle, which improves the appearance after nitriding.

[0022] like Figure 1 , Figure 2 As shown, the connecting part includes a vertical block 2, a slot 3 is opened on the end face of the vertical block 2 away from the frame 101, the end face of the vertical block 2 close to the frame 101 is fixedly connected to the frame 101, and a first screw hole 4 is opened on one side of the vertical block 2.

[0023] The vertical block 2 in the upper frame 101 is connected to the frame 101 in such a way that the bottom surface of the upper vertical block 2 is fixedly connected to the top surface of the upper frame 101, and a slot 3 is provided on the top surface of the vertical block 2; the vertical block 2 in the lower frame 101 is connected to the frame 101 in such a way that the top surface of the lower vertical block 2 is fixedly connected to the bottom surface of the lower frame 101, and a slot 3 is provided on the bottom surface of the vertical block 2; taking the upper frame 101 in a set of frame groups 1 as an example, the vertical blocks 2 are fixedly installed on the top surface of the frame 101, and the four vertical blocks 2 are respectively located at the four corners of the frame 101. Then, the vertical blocks 2 are detachably connected to the height adjustment part, and the installation is completed in sequence.

[0024] like Figure 5 As shown, the height adjustment part includes a first connecting component, a second connecting component, an adjusting component, and a locking component. The first connecting component is fixedly connected to the adjusting component, and the second connecting component is detachably connected to the adjusting component. The second connecting component, the adjusting component, and the first connecting component are arranged sequentially from top to bottom. The vertical block 2 is locked to the first connecting component or the second connecting component through the locking component.

[0025] The first connecting component is detachably connected to the lower vertical block 2, and the second connecting component is detachably connected to the upper vertical block 2. The adjusting component adjusts the distance between the first connecting component and the second connecting component. After the first connecting component and the second connecting component are connected to the vertical block respectively, the locking component connects the first connecting component to the vertical block or the second connecting component to the vertical block.

[0026] like Figure 5 As shown, the first connecting component includes a first support block 5, a first groove 6 is formed at the bottom of the first support block 5, a first limiting block 7 is fixedly installed on the inner wall of the top of the first groove 6, the vertical block 2 can be inserted into the first groove 6, the first limiting block 7 can be inserted into the slot 3, and a second screw hole 8 is formed on one side of the first support block 5 and one side of the first limiting block 7.

[0027] The center of the second screw hole 8 on the first support block 5 and the center of the second screw hole 8 on the first limiting block 7 are both on the same horizontal plane. The vertical block 2 is inserted into the first groove 6, and at the same time the first limiting block 7 is inserted into the slot 3. At this time, the first screw hole 4 and the second screw hole 8 are on the same horizontal plane. Then, the vertical block 2 is connected to the first support block 5 and the first limiting block 7 by the locking member.

[0028] like Figure 5 As shown, the second connecting component includes a second support block 9, a second groove 10 is formed at the top of the second support block 9, a second limiting block 11 is fixedly installed on the inner wall of the bottom end of the second groove 10, the vertical block 2 can be inserted into the second groove 10, the second limiting block 11 can be inserted into the slot 3, and a third screw hole 12 is formed on one side of the second support block 9 and one side of the second limiting block 11.

[0029] The center of the third screw hole 12 on the second support block 9 and the center of the third screw hole 12 on the second limiting block 11 are both on the same horizontal plane. The vertical block 2 is inserted into the second groove 10, and the second limiting block 11 is inserted into the slot 3. At this time, the first screw hole 4 and the third screw hole 12 are on the same horizontal plane. Then, the vertical block 2 is connected to the second support block 9 and the second limiting block 11 by the locking member.

[0030] like Figure 5 As shown, the adjusting component includes a threaded rod 13, the bottom end of which is fixedly installed on the top end of the first support block 5. An adjusting nut 14 is threadedly fitted onto the threaded rod 13. A blind hole 15 is opened at the bottom end of the second support block 9. A threaded sleeve 16 is installed in the blind hole 15 with a bearing. The bottom end of the threaded sleeve 16 is open, and an internal thread is opened on the inner wall of the threaded sleeve 16. The top end of the threaded rod 13 is inserted into the threaded sleeve 16 and threadedly fitted with the internal thread. The top end of the adjusting nut 14 is fixedly connected to the bottom end of the threaded sleeve 16.

[0031] The outer circumference of the threaded sleeve 16 is fixedly connected to the inner wall of the inner ring of the bearing, and the outer wall of the outer ring of the bearing is fixedly connected to the inner wall of the blind hole 15. The bearing can be a high-temperature resistant deep groove ball bearing. When it is necessary to adjust the distance between the first support block 5 and the second support block 9, rotate the adjusting nut 14 to drive the threaded sleeve 16 to rotate. The adjusting nut 14 and the threaded sleeve 16 move up and down along the threaded rod 13, which drives the upper second support block 9 to move up and down to adjust the distance between the first support block 5 and the second support block 9. After the adjustment is completed, the threaded sleeve 16 will not jam during the rotation due to the connection of the bearing.

[0032] like Figure 1 As shown, the locking element includes a bolt, which can pass through a first screw hole and a second screw hole or a first screw hole and a third screw hole.

[0033] The thread is not shown in the figure. When the vertical block 2 is inserted into the first support block 5, the bolt passes through the first screw hole 4 and the second screw hole 8, which are on the same horizontal plane, to connect the first support block 5, the first limiting block 7 and the vertical block 2. When the vertical block 2 is inserted into the second support block 9, the bolt passes through the first screw hole 4 and the third screw hole 12, which are on the same horizontal plane, to connect the second support block 9, the second limiting block 11 and the vertical block 2.

[0034] like Figure 1 , Figure 2 , Figure 7 As shown, the top surface of the frame 101 has several through holes 17. A vertical rod 18 is fitted inside the several through holes 17 located on the same vertical center line. A ring is fixedly installed at the top of the vertical rod 18, and a screw is fixedly installed at the bottom of the vertical rod 18. A nut is threaded on the screw.

[0035] Through holes are opened on the top surface of the four side frames of frame 101. After the frame 101 is installed from bottom to top, a vertical rod 18 is passed through several through holes 17 located on the same vertical center line. Then, the nut is screwed into the screw. At this time, the nut is located on the bottom surface of the lowest frame 101 and is in contact with the frame 101. The four vertical rods 18 connect the frames arranged vertically together. The frames installed together can be hoisted into the nitriding furnace through the ring. The vertical rods 18 can also further increase the constraint between the frames, prevent the frames from moving, and increase stability.

[0036] The frame 101, connecting block 102, placement net, vertical block 2, first support block 5, second support block 9, first limiting block 7, and second limiting block 11 are all made of 202 stainless steel.

[0037] 202 stainless steel has good high-temperature resistance and oxidation resistance, which can adapt to the high-temperature environment during nitriding treatment and prevent the tooling from undergoing severe oxidation or structural strength reduction during repeated heating and cooling cycles. At the same time, it has a certain degree of corrosion resistance, which can resist the erosion of corrosive gases or liquids that may be generated during nitriding and extend the service life of the tooling. In addition, 202 stainless steel has moderate mechanical strength and is relatively easy to process and form, which can meet the structural accuracy requirements of various parts of the tooling. Moreover, compared with other high-alloy stainless steels, it is more cost-effective, which helps to control the overall manufacturing cost of the tooling.

[0038] A method for using a nitriding treatment fixture: I. Preparations before use Tooling condition inspection Visual inspection: Check whether there are any problems such as deformation, cracks, or weld detachment in the various parts of the tooling (frame assembly 1, connecting parts, height adjustment parts, vertical rod 18, etc.), whether the netting is damaged or the steel wire is loose, and whether the threaded connection parts (such as bolts and adjusting nuts 14) are rusted or stripped. Functional check: Rotate the adjusting nut 14 of the height adjustment part to confirm that the second support block 9 can move up and down smoothly along the threaded rod 13 without jamming; check whether the locking part (bolt) can pass smoothly through the screw hole and be tightened, and whether the insertion and removal of the vertical block 2 and the first and second support blocks are smooth, without being too tight or too loose. Cleaning: Use compressed air to blow away dust and debris from the tooling surface. If there is oil or nitriding residue, wipe it clean with a high-temperature resistant cleaner to avoid contaminating the engine valves or affecting the nitriding effect. Preparation of supporting tools and equipment Prepare hoisting equipment (such as overhead cranes and lifting tools), check the load-bearing capacity of the hoisting equipment (it must be greater than the total weight of the tooling and valves), and the integrity of the wire rope or hook; prepare wrenches (compatible with bolts and adjusting nuts 14), gloves (high temperature resistant and non-slip), safety glasses and other operating tools and protective equipment. Check the status of the nitriding furnace: Confirm that the temperature control system, gas supply system (such as ammonia), and exhaust system of the nitriding furnace are normal, the furnace is clean and free of debris, the furnace door is well sealed, and preheat the nitriding furnace to the preset initial temperature in advance.

[0039] Engine valve preparation Pre-treatment is performed on engine valves that require nitriding: remove oxide scale, oil stains, and burrs from the valve surface, and ensure surface cleanliness through cleaning and drying; classify valves according to specifications (such as diameter and height) to facilitate orderly placement on the placement net later. II. Tooling Assembly and Spacing Adjustment Frame group basic splicing Based on the number and height of the valves to be processed, determine the number of frames 1 to be used (refer to the load-bearing capacity of the tooling design to avoid excessive weight due to too many frames). Place the bottom frame 1 on a flat ground or operating platform as the reference frame 1. Spacing adjustment (choose one of two methods) Method 1: The second support block moves the upper frame. Install the connecting part and the height adjustment part: Insert the vertical block 2 on the top surface of the lower reference frame assembly 1 into the first groove 6 of the first support block 5, and at the same time ensure that the first limiting block 7 is inserted into the slot 3 of the vertical block 2. At this time, the first screw hole 4 and the second screw hole 8 are aligned. Use bolts to pass through the screw holes and tighten them to complete the fixing of the height adjustment part and the lower reference frame assembly. Install the upper frame assembly: Insert the vertical block 2 on the bottom of the upper frame assembly 1 into the second groove 10 of the second support block 9, insert the second limiting block 11 into the slot 3, align the first screw hole 4 and the third screw hole 12, and then gently tighten the bolts (do not tighten them, leave room for fine adjustment). Adjusting the gap: Referring to the height of the engine valve, rotate the adjusting nut 14 of the height adjustment part: When rotated clockwise, the threaded sleeve 16 moves upward along the threaded rod 13, driving the second support block 9 and the upper frame assembly to rise, increasing the gap between the upper and lower frame assemblies; when rotated counterclockwise, the gap decreases until the gap is slightly greater than the valve height (usually leave 5-10mm to ensure that the valves are not stacked or bumped after placement). Fixed spacing: After the spacing is adjusted, tighten the bolts connecting the upper frame group and the second support block 9, and use a level to check the flatness of the upper and lower frame groups to ensure that the frame 101 is not tilted; check again whether all bolts are tightened to prevent the tooling from loosening in subsequent operations. Method 2: First adjust the spacing between the support blocks, then install the upper frame. Preset support block spacing: Place the height adjustment unit independently on the operating platform. Referring to the height of the engine valve, rotate the adjusting nut 14: When rotated clockwise, the threaded sleeve 16 moves upward along the threaded rod 13, increasing the distance between the first support block 5 and the second support block 9; when rotated counterclockwise, the distance decreases until the distance between the two is slightly greater than the valve height (usually leave 5-10mm), thus completing the spacing preset. Connect the lower reference frame assembly: Insert the vertical block 2 on the top surface of the lower reference frame assembly 1 into the first groove 6 of the first support block 5, while ensuring that the first limiting block 7 is inserted into the slot 3 of the vertical block 2, aligning the first screw hole 4 with the second screw hole 8, and tighten the bolts through the screw holes to complete the fixing of the height adjustment part to the lower reference frame assembly. Connect the upper frame assembly: Insert the vertical block 2 on the bottom surface of the upper frame assembly 1 into the second groove 10 of the second support block 9, while ensuring that the second limiting block 11 is inserted into the slot 3 of the vertical block 2, align the first screw hole 4 with the third screw hole 12, pass the bolt through the screw hole and tighten it to complete the fixing of the upper frame assembly and the height adjustment part. Calibrate flatness: Use a level to check the flatness of the upper and lower frame assemblies to ensure that frame 101 is not tilted; if there is a slight tilt, loosen the connecting bolts between the first support block 5 and the lower frame assembly, fine-tune the position of the height adjustment part, and then tighten them again until the flatness meets the requirements. Multiple frame groups for extended assembly If you need to assemble three or more frame groups, repeat the above "spacing adjustment" steps (choose one adjustment method): use the frame group that has been fixed above as the new "lower reference frame group", continue to connect the new height adjustment part to the upper frame group, until the assembly of all frame groups is completed. Vertical pole installation and overall fixing Insert the four vertical rods 18 into the through holes 17 of the uppermost frame group, and pass them through the through holes 17 of each of the lower frame groups in sequence, until the screw at the bottom of the vertical rod extends out of the bottom surface of the lowermost frame group; screw nuts into the screws and tighten them clockwise until the nuts are in contact with the bottom surface of the lowermost frame 101 to further fix all frame groups and prevent the frames from shifting after assembly. III. Engine Valve Placement Placement Principles and Operation The "staggered placement" method is adopted: the engine valves are placed in the mesh of the placement net, ensuring that the axes of adjacent valves do not coincide, the bottom of the valves are in contact with the placement net (only four points of contact, to avoid the circular contact affecting the nitriding appearance), and the gap between the valves is not less than 5mm, so as to facilitate the flow of gas (such as ammonia) and liquid (such as condensate) during the nitriding process and ensure the uniformity of nitriding. Layered placement control: The valves of each frame group should be placed according to the above principles. The number of valves in the same layer should be evenly distributed to avoid local overweight and deformation of the placement net. Handle with care during placement to prevent valve collisions that may cause scratches or deformation. Also, prevent valves from extending beyond the edge of frame 101 to prevent them from falling off during hoisting. Check after placement Visual inspection: Confirm that all valves are placed stably in the placement mesh without tilting or stacking, and that there is sufficient space between the top of the valve and the placement mesh of the upper frame assembly (or the top of the tooling); check if the placement mesh is significantly sagging due to the weight of the valves. If so, reduce the number of valves in that layer or replace it with a stronger placement mesh.

[0040] IV. Tooling hoisting and nitriding furnace operation tooling hoisting Operators wearing protective gloves and goggles hook the hook of the hoisting equipment onto the ring at the top of the vertical rod 18, ensuring that the hook is aligned with the center of gravity of the tooling (usually the geometric center of the tooling). The hoisting equipment is then slowly lifted until the tooling is 10-20cm off the ground, at which point the hoisting equipment is paused to check whether the tooling is balanced, whether any connections are loose, and whether there is a risk of valves falling off. After confirming that there are no abnormalities, move the hoisting equipment smoothly and slowly send the tooling into the nitriding furnace, ensuring that the tooling is placed in the center of the furnace and does not come into contact with the furnace wall or the heating elements inside the furnace; lower the tooling onto the support inside the furnace, slowly release the hook to separate the hook from the ring, and then move the hoisting equipment out of the nitriding furnace. Nitriding Furnace Parameter Settings and Operation Close the nitriding furnace door and seal the furnace opening. According to the requirements of the gas valve nitriding process (such as when the material is alloy cast iron, the temperature is usually set to 520-560℃, the holding time is 4-6 hours, and the ammonia flow rate is 0.5-1m³ / h), set the temperature and holding time in the temperature control system, start the gas supply system to introduce ammonia, and at the same time open the exhaust system to ensure that the waste gas (such as hydrogen and nitrogen) in the furnace is discharged smoothly. During the nitriding process, the temperature, gas flow rate, and furnace pressure should be checked regularly through the furnace monitoring system or parameter display screen. If any abnormal parameters occur (such as a sudden rise or fall in temperature or an interruption in ammonia flow), the operation should be stopped immediately, and the fault should be investigated before continuing. V. Post-nitriding treatment and tooling maintenance Tooling removal and valve extraction After the nitriding process is completed, first shut off the gas supply system and wait for the furnace temperature to drop below 200℃ (to avoid deformation of the tooling or burns to the operator caused by high temperature during hoisting). Then open the furnace door, use the hoisting equipment to hook the ring again, and slowly hoist the tooling out of the nitriding furnace. Place it in a ventilated and dry cooling area to cool naturally to room temperature. After cooling, unscrew the nut at the bottom of the vertical rod 18 and remove the vertical rod; then unscrew the bolt connecting the height adjustment part and the vertical block 2 and disassemble each frame assembly; finally, remove the nitrided engine valves one by one from the placement net and put them into a special storage box to avoid oxidation or contamination of the valve surface. Tool cleaning and maintenance Cleaning: Use a wire brush or compressed air to clean the nitriding residue (such as nitriding powder) on the surface of the tooling. If the residue is difficult to remove, a high-temperature and high-pressure water gun can be used to rinse it (the water temperature should not exceed 80°C). The pressure of the high-pressure water gun should not exceed 0.8 MPa to avoid damaging the placement net due to excessive water pressure. After rinsing, wipe it dry with a cloth and place it in a ventilated place to dry completely. Maintenance and Care: Check the wear of each component: If bolts and adjusting nuts 14 are rusted, apply high-temperature grease; if the netting is slightly deformed, it can be leveled and repaired, and if it is severely damaged, it needs to be replaced; if the threaded sleeve 16 of the height adjustment part and the bearing are stuck, they need to be disassembled, cleaned of impurities, and lubricated; after all components are maintained, store them in a dry and ventilated warehouse to avoid rust caused by a humid environment. Precautions for storing tooling When storing, tooling components should be stacked in categories. Frame group 1 should be laid flat to avoid deformation caused by vertical placement. Small components such as the height adjustment unit and vertical rod 18 should be placed in a special toolbox to prevent loss. The stored tooling components should be inspected regularly (every 3 months). If rust or deformation is found, rust removal and repair should be carried out in time to ensure that the tooling is in good working order for the next use.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A nitriding treatment fixture, characterized in that, It includes an array frame group (1), an array height adjustment part, and an array connection part. The frame group (1) consists of two upper and lower frames (101), several connecting blocks (102), and a placement net. The connecting blocks (102) are located between the two frames (101) and are fixedly connected to the frames (101). The placement net is fixedly installed inside the frames (101). The array frame groups (1) are arranged sequentially from top to bottom. The connection part is fixedly connected to the frame group. The height adjustment part is located between two adjacent upper and lower frame groups (1) and is detachably connected to the connection part.

2. The nitriding treatment fixture according to claim 1, characterized in that, The connecting part includes a vertical block (2), a slot (3) is opened on one end face of the vertical block (2) away from the frame (101), the end face of the vertical block (2) close to the frame (101) is fixedly connected to the frame (101), and a first screw hole (4) is opened on one side of the vertical block (2).

3. The nitriding treatment fixture according to claim 2, characterized in that, The height adjustment part includes a first connecting component, a second connecting component, an adjusting component, and a locking component. The first connecting component is fixedly connected to the adjusting component, and the second connecting component is detachably connected to the adjusting component. The second connecting component, the adjusting component, and the first connecting component are arranged in order from top to bottom. The vertical block (2) is locked to the first connecting component or the second connecting component by the locking component.

4. The nitriding treatment fixture according to claim 3, characterized in that, The first connecting component includes a first support block (5), a first groove (6) is opened at the bottom of the first support block (5), a first limiting block (7) is fixedly installed on the inner wall of the top of the first groove (6), a vertical block (2) can be inserted into the first groove (6), the first limiting block (7) can be inserted into the slot (3), and a second screw hole (8) is opened on one side of the first support block (5) and one side of the first limiting block (7).

5. The nitriding treatment fixture according to claim 4, characterized in that, The second connecting component includes a second support block (9), a second groove (10) is opened at the top of the second support block (9), a second limiting block (11) is fixedly installed on the inner wall of the bottom end of the second groove (10), the vertical block (2) can be inserted into the second groove (10), the second limiting block (11) can be inserted into the slot (3), and a third screw hole (12) is opened on one side of the second support block (9) and one side of the second limiting block (11).

6. The nitriding treatment fixture according to claim 5, characterized in that, The adjusting component includes a threaded rod (13), the bottom end of which is fixedly installed on the top end of the first support block (5). An adjusting nut (14) is threadedly fitted on the threaded rod (13). A blind hole (15) is opened at the bottom end of the second support block (9). A threaded sleeve (16) is installed in the blind hole (15) with a bearing. The bottom end of the threaded sleeve (16) is open. An internal thread is opened on the inner wall of the threaded sleeve (16). The top end of the threaded rod (13) is inserted into the threaded sleeve (16) and threadedly fitted with the internal thread. The top end of the adjusting nut (14) is fixedly connected to the bottom end of the threaded sleeve (16).

7. The nitriding treatment fixture according to claim 6, characterized in that, The locking element includes a bolt, which can pass through a first screw hole and a second screw hole or a first screw hole and a third screw hole.

8. The nitriding treatment fixture according to claim 7, characterized in that, The frame (101) has several through holes (17) on its top surface. A vertical rod (18) is fitted into the several through holes (17) located on the same vertical center line. A ring is fixedly installed at the top of the vertical rod (18), and a screw is fixedly installed at the bottom of the vertical rod (18). A nut is threaded onto the screw.

9. A nitriding treatment fixture according to claim 8, characterized in that, The frame (101), connecting block (102), placement net, vertical block (2), first support block (5), second support block (9), first limiting block (7), and second limiting block (11) are all made of 202 stainless steel.

10. A method of using a nitriding treatment fixture, characterized in that, The nitriding treatment fixture according to claim 9, the usage steps include: S1. Preparations before use: S11. Tooling condition inspection: Check the integrity of the frame assembly (1), connecting parts, height adjustment parts, and vertical rods (18), confirming that there is no deformation, cracks, or weld detachment, that the mesh is undamaged and the steel wire is not loose, and that the threaded connection parts are free from rust or stripping; rotate the adjusting nut (14) of the height adjustment part to verify the smooth movement of the second support block (9) along the threaded rod (13), and check the smoothness of the locking part and the screw hole fit and the insertion and removal fit of the vertical block (2) and the support block; use compressed air to remove debris from the tooling surface, and if there is oil or nitriding residue, wipe it clean with a high-temperature resistant cleaner; S12. Preparation of supporting equipment and tools: Prepare lifting equipment with a load-bearing capacity greater than the total weight of the tooling and engine valves, check the integrity of its hooks and wire ropes, equip with wrenches that are compatible with bolts and adjusting nuts (14) and high-temperature resistant anti-slip gloves and protective glasses; check the normality of the nitriding furnace temperature control system, ammonia supply system and exhaust system, ensure that the furnace is clean and the furnace door is well sealed, and preheat the nitriding furnace; S13. Engine valve preparation: Remove oxide scale, oil stains and burrs from the valve surface, and classify them according to diameter and height specifications after cleaning and drying; S2. Tooling assembly and spacing adjustment: S21. Basic operation of frame assembly: Determine the number of frame groups (1) to use based on the number and height of valves. Place the bottom frame group (1) on a flat platform. If multiple frame groups need to be assembled, select one of the following two spacing adjustment methods: Method 1: Dynamic Adjustment S21a1. First, insert the vertical block (2) on the top surface of the lower frame assembly (1) into the first groove (6) of the first support block (5), so that the first limiting block (7) is embedded in the slot (3) and the first screw hole (4) is aligned with the second screw hole (8), and fix the height adjustment part to the lower frame assembly with bolts; S21a2. Rotate the adjusting nut (14) to move the second support block (9) up and down along the threaded rod (13) until the distance between the top surface of the second support block (9) and the mesh of the lower frame assembly (1) is 5-10mm larger than the valve height; S21a3. Insert the vertical block (2) on the bottom surface of the upper frame assembly (1) into the second groove (10) of the second support block (9), so that the second limiting block (11) is embedded in the slot (3) and the first screw hole (4) is aligned with the third screw hole (12), and fix the upper frame assembly and the height adjustment part with bolts; Method 2: Preset Adjustment S21b1. First, place the height adjustment unit independently, and rotate the adjusting nut (14) so ​​that the distance between the first support block (5) and the second support block (9) is 5-10mm larger than the valve height, thus completing the spacing preset; S21b2. Insert the vertical block (2) on the top surface of the lower frame assembly (1) into the first groove (6) of the first support block (5), so that the first limiting block (7) is embedded in the slot (3) and the first screw hole (4) is aligned with the second screw hole (8), and fix the height adjustment part to the lower frame assembly with bolts; S21b3. Insert the vertical block (2) on the bottom surface of the upper frame assembly (1) into the second groove (10) of the second support block (9), so that the second limiting block (11) is embedded in the slot (3) and the first screw hole (4) is aligned with the third screw hole (12), and fix the upper frame assembly and the height adjustment part with bolts; S22. Multiple expansion and horizontal calibration: If three or more frame groups need to be assembled, repeat any of the adjustment methods in S21 and stack the frame groups in sequence; after assembling each group, use a level to check the flatness of all frame groups to ensure that there is no tilt, and recheck the tightness of all bolts; S23. Installation and fixing of vertical rods: Insert (4) vertical rods (18) through the through holes (17) of the uppermost frame group, and then through the through holes (17) of all the lower frame groups in sequence. Screw nuts into the screws at the bottom of the vertical rods (18) so that the nuts fit tightly against the bottom surface of the lowermost frame group (1) to achieve overall fixing. S3. Engine valve placement: S31. Place the valves into the mesh of the placement net in an alternating manner, ensuring that the axes of adjacent valves do not coincide, the bottom of the valves are in four-point contact with the placement net, and the gap between valves is not less than 5mm; the valves in the same layer are evenly distributed, and are placed gently without exceeding the edge of the frame (101); S32. Visually inspect whether the valve is stable and not stacked, and ensure that there is at least 3mm space between the top of the valve and the placement net of the upper frame assembly. Check whether the placement net is dented or deformed due to the load. S4. Tooling hoisting and nitriding furnace operation: S41. The operator wears protective equipment and hooks the hook of the hoisting equipment onto the ring at the top of the vertical rod (18). The position of the hook is adjusted so that the center of gravity of the tool coincides with the center line of the hook. The tool is slowly lifted to 10-20cm off the ground and then paused. The tool is left to stand for 30 seconds to observe its balance and check whether the connection parts are loose or the valves are displaced. After confirming that there are no abnormalities, the hoisting equipment is moved smoothly and the tool is slowly sent into the nitriding furnace. The distance between the tool and the furnace wall is not less than 50mm. After lowering it into the furnace support, the hook is slowly separated and the hoisting equipment is removed. S42. Close the nitriding furnace door and check the sealing performance. Set the nitriding process parameters according to the valve material. Start the temperature control system and gas supply system. Record the furnace temperature and ammonia pressure every 30 minutes during the nitriding process. If the temperature fluctuation exceeds ±5℃ or the ammonia pressure is abnormal, stop the operation immediately and troubleshoot the fault. S5. Post-nitriding treatment and tooling maintenance: S51. After nitriding is completed, shut off the ammonia supply system and keep the exhaust system running for 30 minutes. After the residual ammonia in the furnace is discharged, stop the exhaust system. After the furnace temperature naturally drops below 200℃, open the furnace door and use hoisting equipment to lift the tooling out and place it on a ventilated and dry cooling platform to cool naturally to room temperature. After cooling, first unscrew the nut at the bottom of the vertical rod 18 and take out the vertical rod. Then, remove the bolts connecting the height adjustment part and the vertical block 2, disassemble each frame group, and take out the valves one by one and put them into the special storage box. S52. Tooling cleaning and maintenance: Use a wire brush to remove the nitride powder adhering to the tooling surface. For stubborn residues, use a high-pressure water gun with a temperature not exceeding 80°C to rinse. After rinsing, wipe dry with a cotton cloth and place in a ventilated place to air dry. Check the thread condition of the bolts and adjusting nuts (14). For rusted parts, polish with fine sandpaper and apply high-temperature resistant grease. For slightly deformed placement nets, use a special clamp to level and restore them. If the placement net has broken wires or deformed mesh, replace it with a new placement net. For the height adjustment part that is stuck in rotation, disassemble the threaded sleeve (16) and bearing, clean the internal impurities, apply high-temperature grease, and reassemble. S6. Tooling storage: Stack the frame assembly (1) flat, and classify small parts such as vertical rods (18), bolts, adjusting nuts (14) into a dedicated toolbox with dividers; keep the storage environment dry and ventilated, and avoid direct sunlight; inspect the stored tooling parts every 3 months, remove rust from rusted parts in time, and repair or replace deformed parts.

Images