Pendulum shaft anti-fracture design method

Abstract

The invention discloses an anti-fracture design method for a pendulum shaft, which comprises the following steps of: optimizing a shaft material and a process, and designing a shaft end to be conical and gradually transited for resisting autorotation centrifugal force; a buffer piece is additionally arranged between the bearing seat and the shaft fixing frame and is used for absorbing alternating force during up-down floating; the tooth form of a single-side driving gear pair of the shaft section is changed from a straight tooth form into a helical tooth form, so that the shaft is prevented from being damaged by torsion generated by asynchronism of two sides caused by single-side driving; by improving the material mechanical property and heat treatment of the shaft, the bending strength and bending strength of the shaft are improved, the two ends of the shaft are designed to be conical and are transited step by step, rotation stress is transmitted step by step, fracture deformation caused by self-transmission centripetal stress of the shaft is avoided, the bending resistance and bending resistance of the designed pendulum shaft are greatly improved, the service life is greatly prolonged, and the service life of the pendulum shaft is prolonged. The novel design method also has the advantages of improving the shaft operation stability and reducing the operation noise, so that the production field is more beneficial to the work of staff.

Description

Technical Field

[0001] The invention relates to the technical field of mineral (rock) wool production lines and textile production lines, and specifically to a pendulum shaft anti-fracture design method. Background Art

[0002] The pendulum in the mineral wool production line is a key equipment in the cotton and textile industries. It is responsible for arranging and stacking primary felt, silk fabrics, etc. to improve production efficiency. However, as the main equipment of the production line, the pendulum is very likely to break under the action of triple alternating forces during operation. Analysis shows that when the pendulum is running, the first gravity is the centrifugal force generated by its own rotation, which is along the direction of belt rotation. The second gravity is the gravity moving above the pendulum. The third force is the swinging force of the pendulum's reciprocating horizontal motion. The pendulum shaft is always in a dynamic and static state under the support of these three forces, with high-frequency conversion. The action of the triple force cannot be released, which will inevitably lead to shaft breakage, resulting in production interruption, production capacity fluctuations, unstable product quality, and temporary repairs will also bring safety risks.

[0003] The pendulum of the mineral wool production line is mainly responsible for the transportation and stacking of the cotton felt of the cotton collector. The process requires that the cotton felt must be stacked for more than 19 layers to ensure the tensile and flexural properties of the cotton. However, in actual operation, in order to ensure the long service life of the shaft, the number of stacked layers can only be 14 layers, and the mechanical properties of the cotton are at the lower limit. In order to improve the quality of the cotton and make the number of stacked layers reach 19 layers, the swing frequency needs to be increased, and the shaft system is designed to prevent fracture accordingly. After analysis, the pendulum shaft is subjected to three alternating stresses of F1, F2, and F3 (such as Figure 3 As shown in the figure, the stress cannot be released, resulting in shaft fatigue fracture. Therefore, we propose a pendulum shaft anti-fracture design method. Summary of the invention

[0004] The object of the present invention is to provide a pendulum shaft anti-fracture design method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a pendulum shaft anti-fracture design method, comprising the following steps:

[0006] S1. Optimize the shaft material and process, and design the shaft end into a tapered shape with gradual transition to resist the centrifugal force of self-rotation;

[0007] S2. Add a buffer between the bearing seat and the shaft fixing frame to absorb the alternating force during up and down floating;

[0008] S3. Change the tooth shape of the single-side drive gear pair of the shaft section from straight tooth type to helical tooth type to avoid torque damage to the shaft caused by the asynchronism between the two sides caused by single-side drive.

[0009] Preferably, the shaft material optimization in step S1 is to replace the originally used 45 steel with 40Cr alloy steel.

[0010] Preferably, the shaft process optimization in step S1 includes machining process optimization and heat treatment process optimization;

[0011] The machining process optimization is to round off all corners on the shaft that may cause stress concentration;

[0012] The heat treatment process optimization is to perform stress relief heat treatment on the shaft after the overall processing is completed.

[0013] Preferably, the buffer component in step S2 is a high-elastic buffer pad, and the material of the high-elastic buffer pad is a high-elastic rubber buffer pad with a Shore hardness of 50.

[0014] Preferably, in step S3, the tooth profile of the single-side drive shaft gear pair is changed from spur gear to helical gear, and the gear lubrication is changed from glycerol grease lubrication to high-viscosity thin oil drip lubrication, so as to improve the smoothness of shaft rotation.

[0015] Preferably, the high-viscosity thin oil drop is a thin oil drop with a viscosity of 300.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention improves the mechanical properties of the shaft material and heat treatment to improve the shaft's own anti-bending and anti-flexural strength, and designs the two ends of the shaft to be tapered, with a gradual transition, so that the rotational stress is gradually transmitted to avoid fracture and deformation caused by the shaft's self-transmitted centripetal stress.

[0018] 2. The present invention installs a high-elasticity buffer rubber pad between the bearing seat and the shaft fixing frame to change the rigid connection into a flexible connection. The buffer pad can effectively eliminate the inertia force when the shaft floats up and down, thereby improving the bending and folding resistance of the shaft.

[0019] 3. The present invention changes the shaft driving gear from straight teeth to helical teeth. The helical gear has a more stable engagement, reduces the vibration when the shaft rotates, and improves the shaft's anti-bending ability.

[0020] 4. The present invention adopts high-viscosity thin oil drip lubrication, which greatly improves the lubrication performance and avoids the torsional damage caused by the asynchronous driving of the two ends of the shaft on one side. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the anti-fracture shaft system of the present invention;

[0022] Figure 2 This is the structural diagram of the traditional anti-fracture shaft system;

[0023] Figure 3 This is the shaft force analysis diagram of the traditional anti-fracture shaft system.

[0024] In the figure: 1. shaft; 2. shaft end; 3. fixing bracket; 4. bearing seat; 5. gear pair; 6. bolt; 7. bushing; 8. bearing; 9. locking nut; 10. gear; 11. key; 12. thin oil lubrication; 13. high elastic rubber pad. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] See also Figure 1 and Figure 2 The present invention provides a technical solution: a pendulum shaft anti-fracture design method, comprising the following steps:

[0027] S1. Optimize the shaft material and process, and design the shaft end into a tapered shape with a gradual transition to resist the centrifugal force of rotation.

[0028] It should be noted that Figure 2 The figure in the figure is a structural diagram of a traditional anti-fracture shaft system. A bearing seat 4 is arranged on each of the two fixing frames 3. The bearing seat 4 and the fixing frame 3 are connected by bolts 6. A shaft sleeve 7 is arranged in the bearing seat 4. A bearing 8 is arranged in the shaft sleeve 7. The bearing 8 and the shaft sleeve 7 are connected by a locking nut 9. A shaft 1 is connected between the two fixing frames 3. Shaft ends 2 are arranged at both ends of the shaft 1 located at the bearing seats 4. The ends of the shaft end 2 pass through the fixing frame 3 and are connected to the bearing 8. The shaft end 2 is rotatably connected to the fixing frame 3 through the bearing 8. A key 11 is arranged at the end of the shaft end 2 at one end of the shaft 1. A gear 10 is fixedly connected to the outside of the key 11. A gear pair 5 is arranged on the outside of the gear 10. The gear 10 is lubricated with glycerol grease.

[0029] Figure 3 The figure in the middle is the structural diagram of the anti-fracture shaft system after the optimized design. The shaft material optimization is to replace the original 45 steel with 40Cr alloy steel. 40Cr steel has high tensile strength, fatigue resistance and good toughness, and can withstand higher loads and stresses, thereby improving the overall mechanical properties of the shaft and reducing the risk of fracture; the two ends of the shaft are designed to be tapered, and are realized through gradual transition, which can effectively disperse the rotational stress at both ends of the shaft and avoid stress concentration at the sudden diameter change. The transition part of the shaft releases stress in a gradual manner, thereby reducing cracks and fractures caused by stress concentration; all corners on the shaft that may cause stress concentration are chamfered, which can further reduce the stress concentration effect and extend the service life of the shaft;

[0030] The process optimization of the shaft includes machining process optimization and heat treatment process optimization. The machining process optimization is to round off all the corners on the shaft that may cause stress concentration. The heat treatment process optimization is to perform stress relief heat treatment on the shaft after the overall machining is completed. After the shaft is machined, stress relief heat treatment (such as annealing) is performed to eliminate the internal stress generated during the machining process, which helps to improve the fatigue life of the shaft and avoid early fracture due to stress concentration.

[0031] S2. Add a buffer between the bearing seat and the shaft fixing frame to absorb the alternating force during up and down floating.

[0032] It should be noted that the original rigid connection between the bearing seat and the shaft fixing bracket is changed to a flexible connection, and a high-elastic rubber buffer pad with a Shore hardness of 50 is used, which can effectively absorb the inertial force generated during the up and down reciprocating motion of the shaft and reduce the impact of the resulting vibration on the shaft; the rubber pad can effectively buffer the relative displacement of the bearing seat and the bracket caused by working vibration, reduce the possibility of vibration transmission to the shaft, and reduce fatigue damage to the shaft.

[0033] S3. Change the tooth shape of the single-side drive gear pair of the shaft section from straight tooth type to helical tooth type to avoid torque damage to the shaft caused by the asynchronism between the two sides caused by single-side drive.

[0034] It should be noted that, while changing the tooth profile of the single-sided drive shaft gear pair from spur gear to helical gear, the gear lubrication is changed from glycerol grease lubrication to 300 viscosity thin oil drip lubrication, in order to improve the smoothness of shaft rotation; changing the tooth profile of the single-sided drive shaft gear pair from spur gear to helical gear makes the helical gear meshing more stable, which can effectively avoid the instantaneous impact and vibration caused by the spur gear, thereby reducing the load fluctuation on the shaft and reducing the deformation and damage of the shaft caused by uneven gear meshing; the lubrication of the gear pair is changed from glycerol grease to a 300 viscosity thin oil drip lubrication system, and the thin oil lubrication provides a more stable lubrication effect, reduces the friction coefficient of the gear pair, reduces the temperature generated by the gear during operation, and effectively prevents shaft distortion and damage caused by the lack of synchronization on both sides, and the drip lubrication method ensures that the lubricating oil can be accurately dripped onto the gear meshing to provide the best lubrication effect.

[0035] Experimental design: verify the effect of the pendulum shaft anti-fracture design method designed in the present invention.

[0036] 1. Design comparison group and experimental group:

[0037] Comparison group: pendulum shaft made by traditional design method;

[0038] Experimental group: pendulum shaft using the design method of the present invention.

[0039] 2. Test parameters and test conditions:

[0040] 2.1. Test load and operating conditions: Simulate normal working conditions and apply the load and speed of the pendulum shaft under typical use conditions. Select a standard working environment (for example, production lines of certain mines, metallurgical equipment, etc.) and conduct tests in the actual operating environment of the equipment;

[0041] 2.2. Performance test: including bending and flexural performance test, fatigue life test, rotation stability test and noise measurement.

[0042] 3. Data collection and evaluation:

[0043] 3.1. Stress test: Use stress test equipment to measure the stress distribution of the shaft during operation, especially the stress at both ends of the shaft;

[0044] 3.2. Deformation test: The deformation of the shaft is measured by a high-precision displacement sensor to evaluate the shaft deformation under the two designs;

[0045] 3.3. Vibration and noise test: Use vibration tester and noise monitoring instrument to measure the vibration and noise generated by the shaft during operation;

[0046] 3.4. Life test: Fatigue life test is carried out by simulating long-term working conditions to analyze the time of crack initiation, expansion and final fracture of the shaft.

[0047] 4. Experimental results and analysis:

[0048] 4.1 Shaft material and heat treatment effect

[0049] ① Material selection: The shaft made of 40Cr alloy steel is significantly better than 45 steel in terms of tensile strength, bending resistance and fatigue strength. In actual tests, the shaft made of 40Cr material shows stronger toughness and durability in the stress concentration area.

[0050] ② Stress relief heat treatment: The crack propagation time in the stress concentration area of ​​the pendulum shaft of the experimental group that underwent heat treatment was significantly prolonged, and no early fracture occurred in the test. In contrast, the control group experienced stress concentration and crack propagation under a lower load.

[0051] 4.2. Optimize the process and design the shaft end into a tapered shape with a gradual transition to resist the centrifugal force of rotation.

[0052] ① Tapered transition and chamfered corner design: Experiments show that the stress distribution of the shaft with tapered design and chamfered corners is more uniform during rotation, reducing stress concentration and crack generation; obvious stress concentration appeared at the transition of the control group shaft, while the shaft of the experimental group did not have similar problems.

[0053] ② Bending and breaking of the shaft: The experimental group did not experience fracture or obvious plastic deformation under higher working loads, while the control group showed bending deformation and fatigue cracks earlier.

[0054] 4.3. Add a buffer between the bearing seat and the shaft fixing frame to absorb the alternating force during up and down floating.

[0055] ① Flexible connection design: After using a high-elastic rubber buffer pad with a Shore hardness of 50, the vibration and impact force of the bearing seat in the experimental group were significantly reduced; compared with the control group, the vibration amplitude of the experimental group under the same working conditions decreased by about 30%, effectively reducing the fatigue accumulation of the shaft.

[0056] ② Inertia force absorption: The flexible connection effectively absorbs the inertia force generated by the shaft during its up and down reciprocating motion. The shaft in the experimental group exhibits a more stable working state, and the operating noise of the shaft is significantly reduced.

[0057] 4.4. The tooth type of the single-side drive shaft gear pair is changed from spur gear to helical gear, and the gear lubrication is changed from glycerol grease lubrication to high-viscosity thin oil drip lubrication to improve the smoothness of shaft rotation.

[0058] ① Stability of helical gears: In the experiment, the helical gear pair has a smoother meshing process during operation than the spur gear pair, and the vibration of the gear pair is significantly reduced. Especially at high-speed operation, the design of the helical teeth makes the meshing without obvious impact, avoiding the influence of the vibration of the traditional spur gear pair on the shaft.

[0059] ② Lubrication system optimization: After using 300 viscosity thin oil drip lubrication, the gear pair runs more smoothly, reducing friction and temperature rise. After a period of testing, the lubrication effect is better, the gear pair wear is significantly reduced, and the bearing temperature is also maintained at a low level.

[0060] 5. Conclusion and benefits:

[0061] 5.1. Improve the bending and folding resistance: After using 40Cr alloy steel and stress relief heat treatment, the bending and folding resistance of the shaft is greatly improved. It can withstand higher working loads in long-term use and avoid early fracture.

[0062] 5.2. Extend service life: Through reasonable shaft shape design, flexible connection and optimized drive system, the fatigue life of the pendulum shaft is greatly extended. In actual operation, the pendulum shaft of the experimental group did not suffer from fatigue fracture and had a longer service life.

[0063] 5.3. Improve running stability: The combination of the helical gear pair design and the thin oil drip lubrication system makes the gear pair more stable during operation, reduces vibration and noise, and improves the overall running stability.

[0064] 5.4. Reduce production noise and vibration: Through flexible connection and optimized gear design, the noise and vibration levels in the production process are significantly reduced, which is conducive to improving the production environment and reducing the workload of staff.

[0065] 5.5. Reduce failure rate and safety risks: The optimized design effectively avoids equipment downtime and safety hazards caused by shaft breakage or deformation, and enhances the stability and safety of the equipment.

[0066] To sum up: the present invention provides a pendulum shaft anti-fracture design method. The bending and folding resistance of the pendulum shaft designed by this method is greatly improved, and the service life is greatly extended. The new design method also has the functions of improving the smoothness of shaft operation and reducing operation noise, making the production site more conducive to employees' work, which is beneficial to reducing the overall cost and effectively avoiding the safety hazard risks caused by sudden failure of the production line. It has great practical significance and is worthy of popularization and application.

[0067] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pendulum shaft anti-fracture design method, characterized in that: The steps include: S1. Optimize the shaft material and process, and design the shaft end into a tapered shape with gradual transition to resist the centrifugal force of self-rotation; S2. Add a buffer between the bearing seat and the shaft fixing frame to absorb the alternating force during up and down floating; S3. Change the tooth shape of the single-side drive gear pair of the shaft section from straight tooth type to helical tooth type to avoid torque damage to the shaft caused by the asynchronism between the two sides caused by single-side drive.

2. A pendulum shaft anti-fracture design method according to claim 1, characterized in that: The shaft material optimization in step S1 is to select 40Cr alloy steel as the shaft material.

3. A pendulum shaft anti-fracture design method according to claim 1, characterized in that: The shaft process optimization in step S1 includes machining process optimization and heat treatment process optimization.

4. A pendulum shaft anti-fracture design method according to claim 3, characterized in that: The machining process optimization is to round off all corners on the shaft that may cause stress concentration.

5. A pendulum shaft anti-fracture design method according to claim 3, characterized in that: The heat treatment process optimization is to perform stress relief heat treatment on the shaft after the overall processing is completed.

6. A pendulum shaft anti-fracture design method according to claim 1, characterized in that: The buffer component in step S2 is a high-elastic buffer pad, and the material of the high-elastic buffer pad is a high-elastic rubber buffer pad with a Shore hardness of 50.

7. A pendulum shaft anti-fracture design method according to claim 1, characterized in that: In step S3, the tooth profile of the single-side drive shaft gear pair is changed from spur gear to helical gear, and the gear lubrication is changed from glycerol grease lubrication to high-viscosity thin oil drip lubrication, so as to improve the smoothness of shaft rotation.

8. A pendulum shaft anti-fracture design method according to claim 7, characterized in that: The high-viscosity thin oil drop is a thin oil drop with a viscosity of 300.

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