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CN-122007802-A - Keyless matching equipment dismounting method based on liquid nitrogen cold contraction and heat expansion cooperation

CN122007802ACN 122007802 ACN122007802 ACN 122007802ACN-122007802-A

Abstract

The invention relates to the technical field of mechanical engineering and discloses a disassembly and assembly method of keyless matching equipment based on the synergy of liquid nitrogen, cold contraction and thermal expansion, which comprises the steps of S1 early general preparation, S2 disassembly, S3 assembly and S4 key quality control, wherein the method improves the accuracy of dimension measurement and parameter calculation, avoids disassembly and assembly failure, and comprises the steps of carrying out multi-point measurement (the measuring section of the shaft outside diameter is more than or equal to 3 parts and the measuring mode of the inner hole is coaxial outside diameter) on the inner hole of a matching piece through a micrometer and a dial indicator tool, calculating the thermal expansion and cold contraction target dimension by combining the thermal expansion coefficient and the cold contraction coefficient of the material of the component, ensuring the actual interference to be stable within the design range of 0.08mm-0.1mm, effectively avoiding disassembly and assembly clamping stagnation or component damage caused by parameter deviation, and reducing the disassembly and assembly failure rate to the minimum.

Inventors

  • HE HUI

Assignees

  • 山西中阳钢铁有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The disassembly and assembly method of keyless matching equipment based on the cooperation of liquid nitrogen contraction and expansion comprises the steps of S1 early-stage general preparation, S2 disassembly specific steps, S3 assembly specific steps and S4 key quality control key points, and is characterized in that the S1 early-stage general preparation comprises S101 size accurate measurement and parameter calculation, S102 tool and equipment inspection and debugging, S103 safety protection and environment control; the S2 disassembly specific steps comprise S201 fitting thermal expansion pretreatment, S202 accurate disassembly execution and S203 part inspection and recording after disassembly; the S3 assembling specific steps comprise liquid nitrogen cold contraction treatment of an S301 shaft, synchronous thermal expansion treatment of an S302 matching piece, rapid and accurate S303 assembling operation, and solidification and test verification after S304 assembling; the key quality control key points of S4 include S401 to avoid excessive temperature difference and S402 to test and prove support.
  2. 2. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion is characterized in that the S101 is accurately measured in size and calculated in parameter; The key size of the keyless matching piece is measured in multiple points by adopting a micrometer, a dial indicator or an inner diameter dial indicator, wherein the key size comprises the outer diameter of a shaft and the inner hole diameter of a gear/connecting shaft, the actual interference is recorded (the actual interference is required to be ensured to be within the design range of 0.08mm-0.1 mm), the target size of the inner hole required to be enlarged during thermal expansion and the target size of the shaft required to be reduced during cold contraction are calculated according to measurement data by combining the thermal expansion coefficient and the cold contraction coefficient of a component material, and the failure in disassembly caused by parameter deviation is avoided.
  3. 3. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion of the equipment is characterized in that the S102 tool and the equipment are checked and debugged; The method comprises the steps of preparing a multifunctional disassembling tool, industrial liquid nitrogen, electromagnetic induction heating equipment, a contact thermometer (the measuring range is-200 ℃ to 300 ℃), a surface roughness meter and a non-corrosive cleaning solvent, checking the integrity of the tool, namely, the clamping surface of the disassembling tool is not worn, a liquid nitrogen container is not leaked, the error of a temperature control system of the heating equipment is less than or equal to +/-2 ℃, wiping the surface of a matching piece by using the cleaning solvent, removing greasy dirt and rust impurities, and preventing the impurities from affecting the matching precision or scratching the surface of the part.
  4. 4. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion of the invention as set forth in claim 1, wherein the S103 is characterized by safety protection and environmental control; The operator wears low-temperature protective gloves (resistant to minus 196 ℃), anti-scalding gloves, goggles and anti-static work clothes, sets warning marks in an operation area to clean irrelevant sundries, and controls the environment temperature to be 15-25 ℃ and the humidity to be less than or equal to 60%, so that moisture in the air is prevented from condensing on the surfaces of the components in the low-temperature environment.
  5. 5. The disassembly and assembly method of the keyless matching equipment based on the cooperation of liquid nitrogen and cold contraction and heat expansion is characterized in that the S201 matching piece is subjected to heat expansion pretreatment; The gear or the connecting shaft to be disassembled is fixed on a heating tool, the coaxiality deviation of the part is ensured to be less than or equal to 0.03mm, an electromagnetic induction heating device is started, a step heating mode is adopted, the temperature is raised to 100-120 ℃ at the speed of 5 ℃ per min in the initial stage, the temperature is kept for 5 minutes, the temperature is raised to the target temperature at the speed of 3 ℃ per min, the surface temperature of the part is monitored by a contact thermometer in the whole process, 1 data is recorded every 2 minutes, the change of the metallographic structure of the material caused by local overheating is avoided, and if the temperature exceeds the target value +/-5 ℃, the heating is immediately suspended and the temperature is naturally lowered to a reasonable range.
  6. 6. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion is characterized in that S202 is precisely disassembled and executed; After the components are thermally expanded to the target size and are kept warm for 2 minutes, a clamping assembly of the multifunctional dismounting tool is aligned to the end face of the gear/connecting shaft, the coaxiality of the tool and the components is ensured, a hydraulic pushing assembly is started, axial thrust is slowly applied at a pressure rate of 0.5MPa/min, the thrust is calculated according to the weight of the components, in the dismounting process, the radial runout of the shaft is monitored in real time by a dial indicator, if the runout exceeds 0.02mm, the clamping position of the tool is immediately adjusted, the stable dismounting process is ensured, and when the separation distance between the matching piece and the shaft reaches 5mm-10mm, the thrust rate is reduced to 0.2MPa/min until the complete separation is achieved.
  7. 7. The method for disassembling and assembling the keyless entry device based on the cooperation of liquid nitrogen, cold contraction and heat expansion of the device is characterized in that S203 after disassembling, parts are inspected and recorded; The method comprises the steps of placing the disassembled shaft and the gear/connecting shaft on a dry skid, naturally cooling to normal temperature, detecting the roughness of the matching surface by using a surface roughness meter, checking whether the matching surface has scratches, pits and cracks, measuring the outer diameter of the shaft and the inner hole diameter of a matching piece again, recording size change data, forming a disassembly file, and providing reference for subsequent assembly.
  8. 8. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen shrinkage and thermal expansion is characterized in that the liquid nitrogen shrinkage treatment of the S301 shaft is carried out; The method comprises the steps of vertically placing a shaft into a liquid nitrogen container, ensuring complete immersion of a matching section of the shaft, adjusting cold shrinkage time according to the diameter of the shaft, wherein the cold shrinkage time is 15-20 minutes when the diameter is 50-80 mm, and the cold shrinkage time is 20-25 minutes when the diameter is 80-120 mm, measuring the outer diameter of the matching section of the shaft every 5 minutes by using a long-handle caliper until the size is reduced to be 0.06-0.09 mm smaller than the original diameter of an inner hole of a matching piece, quickly taking the shaft out of liquid nitrogen after cold shrinkage is finished, wiping a frost layer condensed on the surface by using dry cotton cloth, and avoiding rust caused by water residue after the frost layer is melted; S302, synchronous thermal expansion treatment of the matched piece; The gear or the connecting shaft is subjected to thermal expansion treatment while the shaft is contracted, but the target temperature is slightly lower, so that the diameter of the inner hole after thermal expansion is 0.03-0.06 mm larger than the outer diameter of the shaft after contraction, smooth sleeve combination during assembly is ensured, the influence of overlarge gaps on subsequent use is avoided, the temperature is also required to be monitored in real time in the thermal expansion process, 1 data of data is recorded every 1 minute, and the temperature stability is ensured.
  9. 9. The method for disassembling and assembling keyless cooperation equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion of the invention as set forth in claim 1 is characterized in that S303 is a rapid and accurate assembling operation; After the cold-contracted shaft is taken out of liquid nitrogen, the shaft is required to be assembled within 3-5 minutes, the matching section of the shaft is aligned with the inner hole of the gear/connecting shaft after thermal expansion, the axial movement of the shaft is guided by a positioning tool, the coaxiality error of the positioning tool is required to be less than or equal to 0.02mm, the end face of the shaft is tapped by a rubber hammer in a 'slow pushing' mode during the assembly until the step face of the shaft is attached to the end face of a matching piece, after the assembly is completed, radial runout is measured at the two ends of the shaft by a dial indicator, the runout amount is ensured to be less than or equal to 0.02mm, and if the runout amount exceeds the standard, the position of the matching piece is required to be finely adjusted until the requirement is met; S304, curing and testing and verifying after assembly; After the assembly is completed, the components are naturally restored to room temperature in normal temperature environment, touching or moving the components is forbidden during normal temperature environment, the displacement of the matching surface is avoided, after the temperature is completely restored, the radial runout and the end runout of the matching components are measured again to confirm the technical requirements, then 'no-load test operation' is carried out, the assembled equipment is connected with a driving device, no-load operation is carried out for 1 hour, the vibration value and the bearing temperature of the shaft are monitored, the operation is carried out for 2 hours after 80% of rated load, vibration, temperature and noise indexes are continuously tracked, if all parameters are stable, the assembly is qualified, and finally, all data in the assembly process are arranged to form an assembly file, so that experience reference is provided for the overhaul of similar equipment.
  10. 10. The disassembly and assembly method of keyless matching equipment based on the synergy of liquid nitrogen and cold contraction and heat expansion is characterized in that S401 avoids overlarge temperature difference, namely the difference between the highest temperature during heat expansion and the lowest temperature during cold contraction is controlled within 300 ℃, and cracks of the parts caused by overlarge thermal stress are prevented; S402 test demonstrates that when the method is applied to a new type of keyless matching device for the first time, the offline component with the same specification is selected for at least 3 times of disassembly and assembly tests, the dimensional stability and mechanical properties of the tested component are tracked, and the feasibility of the method is confirmed and then the method is applied to actual overhaul.

Description

Keyless matching equipment dismounting method based on liquid nitrogen cold contraction and heat expansion cooperation Technical Field The invention relates to the technical field of mechanical engineering, in particular to a method for disassembling and assembling keyless matching equipment based on the cooperation of liquid nitrogen, cold contraction and heat expansion. Background The keyless fit is used as a core fit mode of high-precision equipment, is widely applied to various industrial transmission systems, and the interference is usually controlled to be 0.08-0.1 mm (the interference of large-scale equipment is higher) so as to ensure the transmission stability and the bearing capacity. However, the existing disassembly and assembly process of keyless matching equipment has a plurality of technical defects, and is difficult to meet the maintenance requirements of precision, safety and high efficiency, and the specific problems are as follows: The dimension measurement and parameter calculation are extensive, namely, single-point measurement or simplified measurement mode is adopted before the existing disassembly and assembly, multi-point accurate detection is not carried out on the outer diameter of the shaft and the diameter of the inner hole of the gear/connecting shaft (for example, the measured section of the outer diameter of the shaft is more than or equal to 3 parts, and the interval between each part is 120 degrees), the actual interference is easy to misjudge, meanwhile, the thermal expansion coefficient (11.5 multiplied by 10- 6/℃-13×10⁻6/° C) and the cold contraction coefficient of the material (for example, alloy steel and 45# steel) of the part are not combined, the thermal expansion and cold contraction target dimension is calculated, and the disassembly and assembly clamping stagnation or the part damage are often caused due to parameter deviation, so that the disassembly and assembly failure rate is higher. The tool equipment is not ready and cleaned in place, the prior art is in a form of checking key equipment such as a multifunctional disassembling tool, a heating device, a liquid nitrogen container and the like, the abrasion condition of a clamping surface of the disassembling tool, the temperature control system error (often exceeding +/-5 ℃) of the heating device and the tightness of the liquid nitrogen container are not strictly verified, tool failure is easy to occur in the disassembling and assembling process, oil stains and rust on the surface of a matching piece are not thoroughly removed by adopting a non-corrosive cleaning solvent, the matching surface is scratched or the matching precision is influenced by impurity residues, and additional repairing treatment is needed later. Disclosure of Invention 1. Technical problem to be solved Aiming at the defects of the prior art, the invention provides a keyless matching equipment disassembly and assembly method based on the cooperation of liquid nitrogen, cold contraction and heat expansion, has the advantages of improving the accuracy of dimension measurement and parameter calculation and the like, and solves the problem of rough dimension measurement and parameter calculation. (II) technical scheme The invention provides a keyless matching equipment disassembly and assembly method based on the cooperation of liquid nitrogen, cold contraction and heat expansion, which comprises the following steps of S1 pre-general preparation, S2 disassembly specific steps, S3 assembly specific steps and S4 key quality control key points, wherein the S1 pre-general preparation comprises S101 size accurate measurement and parameter calculation, S102 tool and equipment inspection and debugging and S103 safety protection and environment control; the S2 disassembly specific steps comprise S201 fitting thermal expansion pretreatment, S202 accurate disassembly execution and S203 part inspection and recording after disassembly; the S3 assembling specific steps comprise liquid nitrogen cold contraction treatment of an S301 shaft, synchronous thermal expansion treatment of an S302 matching piece, rapid and accurate S303 assembling operation, and solidification and test verification after S304 assembling; the key quality control key points of S4 include S401 to avoid excessive temperature difference and S402 to test and prove support. Preferably, the S101 dimension precision measurement and parameter calculation; The key size of the keyless matching piece is measured in multiple points by adopting a micrometer, a dial indicator or an inner diameter dial indicator, wherein the key size comprises the outer diameter of a shaft and the inner hole diameter of a gear/connecting shaft, the actual interference is recorded (the actual interference is required to be ensured to be within the design range of 0.08mm-0.1 mm), the target size of the inner hole required to be enlarged during thermal expansion and the target size of the shaft required to be reduced d