Method for assembling a passive shaft device of a main drive mechanism of a seamless steel tube cold rolling mill

Abstract

The application discloses a kind of assembly methods of seamless steel tube cold rolling mill main drive mechanism passive shaft device, comprising the following steps:1) operation preparation;2) precision correction of rolling bearing;3) left eccentric gear and right eccentric wheel precision assembly;4) flat key precision measurement assembly;5) assembly precision inspection.The tooling of the application is reasonable in design, convenient to use, high in eccentric gear installation precision, and the detection and assembly method is reasonable, convenient to operate, and the working clearance of the rolling bearing is accurate and reliable.The application meets the technical requirements of high alloy element, high strength new steel seamless steel tube cold rolling pipe on the basis of ensuring the precision assembly of passive shaft device, is practical and efficient, safe and reliable, and the quality is stable.

Description

Technical Field

[0001] This invention relates to cold rolling production equipment for producing seamless steel pipes in the metallurgical and machinery industries. More specifically, it relates to an assembly method for the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill, which is particularly suitable for precision assembly operations of passive shaft devices with crank-connecting rod structures under offline conditions. Background Technology

[0002] Seamless steel pipes are common metallurgical products. Due to their high rolling precision, high speed, large production capacity, high yield, and ease of production organization and process technology adjustment, cold rolling technology for seamless steel pipes has become the main method for the production and processing of seamless steel pipes.

[0003] Seamless steel pipe cold rolling production equipment is divided into two-roll and multi-roll types according to the number of rolls. Among them, the two-roll periodic cold rolling mill is the most widely used seamless steel pipe cold rolling mill due to its compact structure, large rolling force, and high production capacity. Typically, a two-roll cold rolling mill consists of a main drive mechanism, a feed and rotation mechanism, a rolling mechanism, a rotary chuck mechanism, a bed mechanism, a feeding (unloading) mechanism, a lubrication mechanism, a hydraulic mechanism, and an electrical control system.

[0004] The main drive mechanism consists of a base, pulley assembly, reduction gear, drive shaft assembly, driven shaft assembly, connecting rods, and other components. Structurally, the base is installed entirely in a concrete pit. Currently, the main drive mechanism can be divided into two types according to the installation position of the base: front-mounted and rear-mounted. In the front-mounted layout, the base of the main drive mechanism is located in front of the rolling mechanism; in the rear-mounted layout, the base is located behind the rolling mechanism. Both can meet the needs of seamless steel pipe transmission; the difference lies in the installation position required by the equipment. The pulley assembly is installed on one side of the base and connected to the main motor by a coupling. The reduction gear is installed between the pulley assembly and the base, and is connected to both the pulley assembly and the drive shaft assembly. The drive shaft assembly is installed on the base (on the outer side) and connected to the reduction gear by a coupling. The driven shaft assembly is installed on the base (on the inner side, adjacent to the rolling mechanism) and connected to the working frame of the rolling mechanism via connecting rods mounted on eccentric gears on both sides of the driven shaft assembly. Therefore, the passive shaft device is the only power output component of the main drive mechanism. In other words, the ultimate function of the main drive mechanism is to drive the working frame to operate effectively.

[0005] During the cold rolling of seamless steel pipes, the main motor outputs power, driving the pulley device to rotate. The pulley device transmits this rotational power to the reduction gear, which then reduces the speed and transmits it to the drive shaft device via a coupling. The drive shaft device, through gear meshing with the driven shaft device, drives the driven shaft device to rotate within the mill base. Meanwhile, the connecting rods mounted on the eccentric gears on both sides of the driven shaft device rotate around the connecting rod pin (i.e., spin) and, under the influence of the driven shaft's rotation, rotate around the main shaft of the driven shaft (i.e., revolve). One rotation and one revolution together drive the work stand to complete one cycle of horizontal reciprocating motion within the rolling mill base. This continuous rotation of the driven shaft device provides the power required for the cold rolling of seamless steel pipes. Therefore, the operating accuracy and stability of the driven shaft not only affect the operating quality of the main drive mechanism but also the overall efficiency of the cold-rolled pipe. Ensuring the operating accuracy of the driven shaft device is a crucial technical indicator for the main drive mechanism and the entire cold rolling mill.

[0006] Combination Figure 1 As shown, the driven shaft assembly mainly consists of a left eccentric gear 11, a right eccentric gear 12 (crank), rolling bearings 14 (double-row short cylindrical roller bearings), a retaining ring 15, a support ring 17, a positioning sleeve 16, a flat key 18, a connecting rod pin 19, and a spacer ring. The accuracy of the driven shaft assembly mainly consists of the assembly accuracy of each component under offline conditions and the installation accuracy of the entire driven shaft assembly under online (installed on the machine base) conditions; both are indispensable. Regarding the assembly accuracy of the driven shaft assembly under offline conditions, it mainly involves three parts: the synchronization accuracy of the left and right eccentric gears, the running clearance (working clearance) of the two sets of rolling bearings, and the axial position accuracy of each component on the main shaft. Among these, the axial position accuracy can be corrected by the support ring during online (machine) installation, but the synchronization accuracy of the left and right eccentric gears and the running clearance (working clearance) of the rolling bearings can only be guaranteed during offline assembly and cannot be corrected during online (machine) installation, directly affecting the operating accuracy, stability, and service life of the driven shaft assembly (see appendix). Figure 2 ).

[0007] In production practice, there are two main sources for offline assembly of driven shaft devices: one is the assembly of new spare parts, and the other is the repair of parts after they have been taken off the production line (machine). Whether assembling new parts or repaired parts, all components need to be assembled. The difference is that repaired parts require a disassembly process, while new parts do not. Currently, the offline assembly process for driven shafts mainly includes: receiving spare parts → cleaning → installing a flat key on one side of the spindle → installing an eccentric gear on one side using the temperature difference method → ​​installing a retaining ring and support ring → installing a rolling bearing using the temperature difference method → ​​installing a positioning sleeve → installing a rolling bearing using the temperature difference method → ​​installing a retaining ring and support ring → installing a flat key on the other side of the spindle → installing an eccentric gear on the other side using the temperature difference method, etc.

[0008] The above method can be used to complete the offline assembly of the driven shaft device, but it has certain shortcomings:

[0009] 1) Errors exist in the left and right eccentric gears: Currently, the flat keys at both ends of the main shaft are used as the guide and installation reference for the left and right eccentric gears. However, due to factors such as the machining accuracy of the keyway, the machining accuracy of the flat key, and the machining accuracy of the keyway and helical tooth profile of the eccentric gears, installation errors occur in the left and right eccentric gears. This error is the deviation in the synchronization accuracy of the same row of teeth of the left and right eccentric gears (with the center of the main shaft and the eccentric gear as the reference, the deviation is in the same or opposite direction, either counterclockwise or clockwise). This error not only affects the meshing accuracy of the driven shaft and the drive shaft after installation, but also causes axial displacement of the driven shaft and drive shaft due to tooth profile deviation, creating potential faults. Currently, even if deviations exist during inspection after the eccentric gears are assembled, they cannot be eliminated.

[0010] 2) Errors exist in the rolling bearing's clearance (operating clearance): This error refers to the clearance 'b' between the outer ring and the inner rings on both sides of the double-row short cylindrical roller bearing. A large clearance will cause runout during the driven shaft's rotation, while a small clearance will cause the bearing to overheat and fail. Therefore, the equivalent of the rolling bearing's clearance (operating clearance) directly affects the service life of the entire driven shaft assembly. Currently, new rolling bearings generally do not undergo clearance measurement and calibration. Furthermore, the clearance of new rolling bearings does not perfectly match the load on the driven shaft during the cold-rolling of seamless steel pipes, posing a potential malfunction.

[0011] In summary, the offline assembly method of the passive shaft device of the main drive mechanism in a seamless steel pipe cold rolling mill cannot fully meet the technical requirements for the operational accuracy and stability of the main drive mechanism during cold rolling. Especially in recent years, enterprises have developed and produced seamless steel pipes of new steel grades with high alloy elements and high strength, which are in high demand in the market. These steel grades have greater resistance to deformation than ordinary steel grades, significantly increasing the load during cold rolling. Consequently, the load on the main drive mechanism, including the passive shaft device, is also increased, leading to a significant increase in the failure rate and maintenance costs of related components. Therefore, only through corresponding technical improvements, optimization of the operation process, and improvement of the assembly accuracy of the passive shaft device under offline conditions can the requirements for cold rolling of seamless steel pipes be met, equipment maintenance costs and downtime reduced, and the enterprise's core market competitiveness further enhanced. Summary of the Invention

[0012] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide an assembly method for the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill. This method features a rationally designed tooling, convenient operation, high precision eccentric gear installation, a reasonable testing and assembly method, convenient operation, and accurate and reliable rolling bearing clearance. While ensuring precise assembly of the passive shaft device, it meets the technical requirements for cold rolling of high-alloy, high-strength seamless steel pipes, offering practicality, efficiency, safety, reliability, and stable quality control.

[0013] To achieve the above objectives, the present invention adopts the following technical solution:

[0014] An assembly method for the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill includes the following steps:

[0015] 1) Work preparation: preparation of materials and preparation of precision calibration gauges for helical gears and modification of spindle keyways;

[0016] 2) Rolling bearing precision calibration: Remove the bearing support ring of the rolling bearing, calibrate the condition of the rolling bearing, obtain the grinding thickness of the bearing support ring, grind and align the bearing support ring to ensure that the working clearance of the rolling bearing is qualified.

[0017] 3) Precision assembly of left and right eccentric gears: The left eccentric gear on one side of the closed keyway of the spindle is assembled using the temperature difference method. The components between the left and right eccentric gears of the driven shaft device are assembled sequentially and oriented. Then, the right eccentric gear is assembled using the temperature difference method, and the synchronization between the right and left eccentric gears is quickly corrected.

[0018] 4) Flat key precision measurement and assembly: Measure the offset between the keyway in the shaft hole of the right eccentric gear and the open through keyway on the main shaft, and prepare and assemble the flat key.

[0019] 5) Assembly accuracy inspection: Inspect the synchronicity of the left and right eccentric gears of the driven shaft assembly, the working clearance of the rolling bearings, and the axial clearance.

[0020] Preferably, in step 1), the work preparation includes safety technical briefing, implementation of on-site safety precautions, preparation of tooling and spare parts, cleaning of spare parts and materials and verification of drawings, preparation of helical gear precision calibration ruler, and modification of passive shaft device spindle keyway.

[0021] Preferably, the helical gear precision calibration gauge has a right-angled structure, which is formed by welding a round steel bar and a rectangular ruler; one end of the round steel bar is welded to one end of the rectangular ruler, and the welding angle is consistent with the inclination of the eccentric gear of the driven shaft device; the surface roughness of the helical gear precision calibration gauge is not less than R. a 1.6.

[0022] Preferably, in the modified passive shaft device spindle keyway, the closed keyway on either side of the spindle is modified into an open through keyway, and the opening side of the open through keyway is connected to the end face of the spindle.

[0023] Preferably, in step 2), the rolling bearing accuracy correction further includes:

[0024] 2.1) Bearing measurement preparation: Place the rolling bearing vertically on the work platform, remove the bearing support ring between the upper inner ring and the lower inner ring of the rolling bearing, and correct the perpendicularity of the outer ring of the rolling bearing.

[0025] 2.2) Measurement of the bearing in its original state: Measure and record the actual distance between the upper inner ring and the lower inner ring of the rolling bearing. Manually rotate the outer ring of the rolling bearing and measure and record the actual distance between the upper inner ring and the lower inner ring of the rolling bearing again.

[0026] 2.3) Determine the grinding thickness of the bearing support ring: Calculate the grinding thickness of the bearing support ring based on the actual distance between the upper and lower inner rings of the rolling bearing and the accuracy requirements of the rolling bearing.

[0027] 2.4) Inspection and confirmation of working clearance of rolling bearing: After grinding, the bearing is assembled between the upper inner ring and the lower inner ring of the rolling bearing using a support ring. The outer ring of the rolling bearing is manually rotated, and the clearance between the rolling element on the upper inner ring and the outer ring is measured and recorded. The actual working clearance of the rolling bearing is calculated. If the actual working clearance is within the equivalent working clearance of the rolling bearing, the working clearance of the rolling bearing is qualified.

[0028] 2.5) Repeat the above steps to complete the precision calibration of the two sets of rolling bearings.

[0029] Preferably, in steps 2.2) and 2.4):

[0030] When measuring the actual clearance between the upper and lower inner rings of a rolling bearing, data should be measured at at least three points; and / or

[0031] When rotating the outer ring of the rolling bearing, rotate at least three revolutions; and / or

[0032] When rotating the outer ring of a rolling bearing, place a weight of not less than 10 kg at the fixed end of the upper inner ring of the rolling bearing.

[0033] Preferably, in step 3), the precision assembly of the left eccentric gear and the right eccentric gear further includes:

[0034] 3.1) Install the flat key and left eccentric gear on one side of the spindle: Orient the flat key in the closed keyway of the spindle, and use the temperature difference method to orient the left eccentric gear on one side of the closed keyway of the spindle so that the end face of the left eccentric gear is flush with the end face of the spindle.

[0035] 3.2) Spindle repositioning: Turn the spindle with the left eccentric gear on its side so that the left eccentric gear is facing down and the open through keyway side of the spindle is facing up, and place it vertically on the work station;

[0036] 3.3) Install the components on the spindle: Install the positioning element, left rolling bearing, positioning sleeve, right rolling bearing, and positioning element sequentially and orientably on the spindle;

[0037] 3.4) Right eccentric gear assembly: The right eccentric gear is heated by temperature difference method. The shaft hole keyway of the right eccentric gear is aligned with the open through keyway of the main shaft for orientation assembly. The synchronization of the right eccentric gear and the left eccentric gear is quickly corrected.

[0038] Preferably, in step 3.4), the rapid correction of the synchronization between the right eccentric gear and the left eccentric gear includes:

[0039] The round steel section of the helical gear precision calibration ruler is placed into the tooth groove of the right eccentric gear. The rectangular ruler of the helical gear precision calibration ruler is freely and vertically pointed to the bottom left eccentric gear. At this time, the offset of the outer and inner angles of the right and left eccentric gears is immediately measured, and the right eccentric gear is tapped to rotate slightly to achieve correction.

[0040] Take three consecutive measurements, including at least the keyway near the shaft hole of the right eccentric gear and the pin near the connecting rod.

[0041] The total time for the calibration process shall not exceed 5 minutes.

[0042] Preferably, in step 5), the assembly accuracy inspection further includes:

[0043] 5.1) Synchronization test of left and right eccentric gears: The synchronization of left and right eccentric gears is tested, the offset of the inner and outer sides of the helical teeth is obtained, and the offset is compared with the helical gear assembly standard of the driven shaft device to determine whether it is qualified.

[0044] 5.2) Inspection of the working clearance of rolling bearings: Check the clearance between the outer ring of the two rolling bearings on the main shaft and the upper inner ring rolling element on its inner side, and compare it with the working clearance standard of the rolling bearing of the driven shaft device to determine whether it is qualified.

[0045] 5.3) Axial clearance inspection of the passive shaft assembly: Use a feeler gauge to inspect the mating points of each component assembled on the main shaft of the passive shaft assembly to ensure that the clearance at each mating point is 0.

[0046] Preferably, in step 5.1), when the offsets of both the inner and outer sides of the helical gear meet the helical gear assembly standard of the driven shaft device, the synchronization of the left and right eccentric gears is qualified; otherwise, disassembly and rework are required; and / or

[0047] In step 5.2), if the clearance between the outer rings of both rolling bearings and the rolling elements of the upper inner rings on their inner sides both meet the working clearance standard for the rolling bearings of the driven shaft device, then the working clearance of the rolling bearings is qualified; otherwise, disassembly and rework are required; and / or

[0048] In step 5.3), if the gap at the mating point of each component assembled on the main shaft of the passive shaft device is not zero, the gap is eliminated by axial pressing so that the gap at the mating point of each component is zero.

[0049] The assembly method of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill provided by the present invention has the following beneficial effects:

[0050] 1) The tooling of this invention is reasonably designed, easy to use, has high installation accuracy of eccentric gears, reasonable testing and fitting methods, convenient operation, and precise control of rolling bearing working clearance. It is practical, efficient, safe, reliable, and has stable quality control.

[0051] 2) This invention, while ensuring the installation accuracy on the passive shaft device, meets the technical requirements for cold-rolled seamless steel pipes made of new high-alloy and high-strength steel grades, thus promoting the core competitiveness of enterprises in the market;

[0052] 3) This invention uses a helical gear precision calibration ruler to achieve precision calibration of eccentric gears during temperature difference orientation assembly operations, with a synchronization error value ≤0.5mm, reducing the experience and skill requirements of operators and facilitating standardized operations;

[0053] 4) This invention optimizes the keyway structure at one end of the spindle, changing the closed keyway into a single-sided open through keyway to meet the requirements of precise key customization after eccentric gear correction, thus providing structural assurance for eccentric gear precision correction.

[0054] 5) This invention employs gauge block measurement, function calculation, and bearing support ring grinding to ensure that the working clearance of the rolling bearing is controlled within the range of 0.02 to 0.10 mm, which meets the enterprise's technical standards;

[0055] 6) This invention achieves precise control of rolling bearing operation by reasonably adjusting the working clearance, thereby increasing load-bearing capacity and extending service life while reducing spindle radial runout;

[0056] 7) This invention effectively improves the operating accuracy and stability of the main drive mechanism, extends the service life of the driven shaft device, reduces equipment downtime and maintenance resource consumption, and has certain effects on eliminating faults, reducing costs and promoting production.

[0057] 8) This invention is applicable to the technical requirements of precision assembly of passive shaft devices for multi-model two-roll periodic cold rolling mills, meets the cold rolling needs of seamless steel pipes of various steel grades and specifications, is replicable and applicable, and promotes the core competitiveness of enterprises in the market.

[0058] 9) This invention is highly versatile and has certain reference and application value for the technical improvement of the main drive mechanism of a two-roll periodic seamless steel pipe cold rolling mill. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill. (a) is a schematic diagram of the passive shaft device, and (b) is a side view of the passive shaft device.

[0060] Figure 2 This is a schematic diagram illustrating the assembly precision of the passive shaft device of the present invention;

[0061] Figure 3 This is a schematic diagram of the rolling bearing clearance correction of the present invention, wherein (a) is a schematic diagram of the rolling bearing clearance, and (b) is a schematic diagram of the actual distance between the upper inner ring and the lower inner ring of the rolling bearing;

[0062] Figure 4 This is a schematic diagram of the structure of a spindle in the prior art, where (a) is the front view and (b) is the side view;

[0063] Figure 5 This is a schematic diagram of the main shaft of the present invention, wherein (a) is a front view and (b) is a side view;

[0064] Figure 6 This is a schematic diagram of the structure of the helical gear precision calibration ruler of the present invention, wherein (a) is a front view of the helical gear precision calibration ruler, (b) is a side view of the helical gear precision calibration ruler, and (c) is a top view of the helical gear precision calibration ruler.

[0065] Figure 7 This is a schematic diagram of the left and right eccentric gear assembly of the present invention, wherein (a) is a schematic diagram of the structure of the oriented assembly of the right eccentric gear, and (b) is a schematic diagram of the short-term correction after the oriented assembly of the right eccentric gear is completed;

[0066] Figure 8 This is a schematic diagram of the flat key structure of the present invention, wherein (a) is a schematic diagram of the standard flat key structure, (b) is a side view of (a), (c) is a schematic diagram of the offset flat key structure, and (d) is a side view of (c).

[0067] Figure 9 This is a process flow diagram of the assembly method of the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill according to the present invention;

[0068] In the diagram, 11. Left eccentric gear; 12. Right eccentric gear; 13. Main shaft; 131. Closed keyway; 132. Open through keyway; 14. Rolling bearing; 141. Upper inner ring; 142. Lower inner ring; 143. Rolling element; 144. Outer ring; 145. Bearing support ring; 15. Retaining ring; 16. Positioning sleeve; 17. Main shaft support ring; 18. Flat key; 181. Standard flat key; 182. Offset flat key; 19. Connecting rod pin; 20. Helical gear precision calibration ruler; 201. Round steel; 202. Rectangular ruler; 21. Working platform; 22. Pad block; 23. Lifting slings. Detailed Implementation

[0069] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0070] A steel pipe plant of a steel company in Shanghai uses an assembly method for the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill (such as LG-180H, LG-110H, LG-60H, LG-80, LG-50, etc.) on various models of two-roll periodic cold rolling mills with an outer diameter of 38mm or more. This method is a technical improvement on the existing operation and maintenance methods of the main drive mechanism of two-roll periodic seamless steel pipe cold rolling mills. It consists of three main processes: precision calibration of rolling bearing 14, precision assembly of left eccentric gear 11 and right eccentric gear 12, and precision measurement and assembly of flat key, and two auxiliary processes: operation preparation and assembly accuracy inspection. That is, operation preparation → precision calibration of rolling bearing 14 → precision assembly of left eccentric gear 11 and right eccentric gear 12 → precision measurement and assembly of flat key → assembly accuracy inspection, so as to ensure that the precision of left eccentric gear 11, right eccentric gear 12 and rolling bearing 14 meets the technical requirements of cold rolling pipe.

[0071] Please combine Figure 9 As shown, the assembly method of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill provided by the present invention includes the following steps:

[0072] 1) Work preparation: Material preparation and preparation of helical gear precision calibration ruler 20 and modification of spindle keyway; further including safety technical briefing, implementation of on-site safety precautions, preparation of tooling and spare parts materials, cleaning of spare parts materials and verification of drawings, preparation of helical gear precision calibration ruler 20, and modification of passive shaft device spindle keyway.

[0073] The specific preparation for the assignment includes:

[0074] Safety briefings and identification of hazards before work, implementation and inspection of on-site safety precautions, preparation of tools, equipment and materials, etc.

[0075] Clean and sanitize spare parts and materials, and verify the consistency between the drawings and the spare parts and materials to ensure that the quantity and accuracy of the spare parts and materials are correct.

[0076] Preparation of helical gear precision calibration ruler 20: combined with Figure 6 As shown, there is one helical gear precision calibration gauge 20, which has a right-angle structure and can be made of 45# medium carbon steel. It is formed by welding a round steel 201 and a rectangular ruler 202. The diameter of the round steel 201 should be 0.10 to 0.20 mm smaller than the width of the eccentric gear tooth groove, and its length should be equal to the width of the eccentric gear. The length of the rectangular ruler 202 should be the total width of the passive shaft device formed by the left and right eccentric gears 12 mounted on the main shaft 13 + 20 to 30 mm, and its width should be equivalent to the diameter of the round steel 201. One end of the round steel 201 is welded to either end of the rectangular ruler 202, and the welding angle is consistent with the slope of the eccentric gear of the passive shaft device being tested. The surface roughness of each component of the gauge 20 should be no less than Ra1.6.

[0077] Modified passive shaft device spindle keyway: combination Figure 5 As shown, the closed keyway 131 on either side of the spindle 13, near the end face of the spindle 13, is milled to form a single-sided open through keyway 132 structure (i.e., the open side of the open through keyway 132 connects to the end face of the spindle 13). The original spindle (see...) Figure 4 As shown, the spindle needs to be modified and processed. The drawings for the new spindle 13 can be modified and completed during the spare parts processing.

[0078] 2) Accuracy calibration of rolling bearing 14: Take out the bearing support ring 145 of rolling bearing 14, calibrate the condition of rolling bearing 14, obtain the grinding thickness of bearing support ring 145 (obtain the grinding thickness value of bearing support ring 145 by measuring the vertical distance of the original bearing support ring installation position), grind and oriented the bearing support ring 145 to make the working clearance of rolling bearing 14 qualified.

[0079] Combination Figure 3 As shown, the precision calibration of rolling bearing 14 specifically includes:

[0080] 2.1) Bearing measurement preparation: Place the double-row short cylindrical roller rolling bearing 14 vertically on the working platform 21, remove the bearing support ring 145 between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14, and use a 90° square to correct the perpendicularity of the outer ring 144 of the rolling bearing 14.

[0081] 2.2) Measurement of the bearing in its original state: Measure and record the actual distance between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14. Manually rotate the outer ring 144 of the rolling bearing 14 and measure and record the actual distance between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14 again.

[0082] Using vernier calipers or gauge blocks, measure the actual distance between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14, which is the width of the original bearing support ring 145. Measure at least three points and record the readings. Then, manually rotate the outer ring 144 of the rolling bearing 14 at least three times, and measure the actual distance between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14 again. Measure at least three points and record the readings. To ensure measurement accuracy, a weight of at least 10 kg can be installed on the top end face of the upper inner ring 141 when manually rotating the outer ring 144.

[0083] 2.3) Determine the grinding thickness of the bearing support ring 145: Calculate the grinding thickness of the bearing support ring 145 based on the actual distance between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14 and the accuracy requirements of the rolling bearing 14.

[0084] The actual distance readings between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14 measured in step 2.3) are integrated and corrected, and their average value is taken. That is, the measured width L of the support ring mounting part inside the rolling bearing 14 is the average of multiple measurements. According to the accuracy requirements of different models of rolling bearings 14, the grinding thickness of the bearing support ring 145 is calculated, that is, L1 = L + L2, where L1 is the grinding thickness of the bearing support ring 145 to be prepared, L2 is the correction value according to the technical requirements, and L is the measured width of the support ring mounting part inside the rolling bearing 14.

[0085] 2.4) Inspection and confirmation of working clearance of rolling bearing 14: After grinding, the bearing support ring 145 is assembled between the upper inner ring 141 and the lower inner ring 142 of rolling bearing 14. The outer ring 144 of rolling bearing 14 is rotated manually, and the clearance between the rolling element 143 on the upper inner ring 141 and the outer ring 144 is measured and recorded. The actual working clearance of rolling bearing 14 is calculated. If the actual working clearance is within the working clearance equivalent of rolling bearing 14, the working clearance of rolling bearing 14 is qualified.

[0086] After grinding, the bearing is oriented and assembled between the upper inner ring 141 and the lower inner ring 142 of the rolling bearing 14 using a support ring 145. The outer ring 144 of the rolling bearing 14 is manually rotated at least three times. The clearance between the rolling element 143 (outer circumferential surface of the short cylindrical roller) on the upper inner ring 141 of the rolling bearing 14 and the outer ring 144 is measured using a feeler gauge. At least three points are measured and the readings are recorded.

[0087] The clearance value between the rolling element 143 and the outer ring 144 on the upper inner ring 141 of the rolling bearing 14, as measured in the aforementioned steps, is obtained by integrating the mean value method. This clearance value is the actual working clearance value b of the rolling bearing 14. The working clearance equivalent specified in the technical requirements is compared with the actual working clearance. If it meets the requirements, it is qualified and can be installed on the spindle 13. If it does not meet the requirements, it needs to be re-grinded or the support ring needs to be replaced until it meets the requirements before it can be installed on the spindle 13.

[0088] 2.5) Repeat the above steps to complete the precision calibration of the two sets of rolling bearings 14.

[0089] 3) Precision assembly of left eccentric gear 11 and right eccentric gear 12: The left eccentric gear 11 on one side of the closed keyway 131 of the spindle 13 is assembled using the temperature difference method. The components between the left eccentric gear 11 and the right eccentric gear 12 of the driven shaft device are assembled in sequence and orientation. Then, the right eccentric gear 12 is assembled using the temperature difference method, and the synchronization between the right eccentric gear 12 and the left eccentric gear 11 is quickly corrected.

[0090] Combination Figure 7 As shown, the precision assembly of the left eccentric gear 11 and the right eccentric gear 12 specifically includes:

[0091] 3.1) Install the flat key and left eccentric gear 11 on one side of the spindle 13: Orient the flat key 181 in the closed keyway 131 of the spindle 13, and use the temperature difference method to orient the left eccentric gear 11 on one side of the closed keyway 131 of the spindle 13, so that the end face of the left eccentric gear 11 is flush with the end face of the spindle 13.

[0092] Install one side flat key: Orient and fix the two semi-circular flat keys (i.e. standard flat key 181) in the closed keyway 131 of the spindle 13, and vertically stand the spindle 13 with the flat key installed at the top on the special work station or work platform 21, and clean the outer surface of the spindle 13 and the flat key.

[0093] Assembly of left eccentric gear 11: The left eccentric gear 11 is heated by temperature difference method. The heated left eccentric gear 11 is lifted to the spindle position by lifting machinery. The shaft hole is cleaned of debris. The shaft hole keyway is aligned with the key of the spindle 13 and then installed in an oriented manner. It is necessary to ensure that the end face of the left eccentric gear 11 is flush with the end face of the spindle 13.

[0094] 3.2) Repositioning of spindle 13: Turn spindle 13 with the left eccentric gear 11 assembled on its side so that the left eccentric gear 11 faces down and the open through keyway 132 of spindle 13 faces up, and place it vertically on the work station (work platform 21).

[0095] After the left eccentric gear 11 is oriented and installed on the main shaft 13, and left to stand in the air for at least five minutes, the main shaft 13 and the left eccentric gear 11 are tilted to the side using a crane, so that the left eccentric gear 11 is facing down and the main shaft 13 is with the optical axis of the mounting parts facing up (the open through keyway 132 is located at the highest point). The main shaft 13 is then vertically placed on a dedicated work station or work platform 21, and the outer circumferential surface of the optical axis part of the main shaft 13 is cleaned.

[0096] 3.3) Install the components on the spindle 13: Install the positioning element, left rolling bearing, positioning sleeve 16, right rolling bearing, and positioning element sequentially and orientably on the spindle 13;

[0097] Install positioning elements (I): Install a spindle support ring 17 on the spindle 13 in an orientation, with its lower end face fitting against the inner end face of the left eccentric gear 11. Install a retaining ring 15 on the spindle 13 with its groove facing upward, with its inner hole fitted onto the outer diameter of the spindle support ring 17, and its end face fitting against the left eccentric gear 11.

[0098] Install the left rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the main shaft support ring 17.

[0099] Install positioning sleeve 16: Install positioning sleeve 16 onto spindle 13 in an orientation, with the lower end face of positioning sleeve 16 fitting against the outer end face of the upper inner ring 141 of the left rolling bearing.

[0100] Install the right rolling bearing: Heat the right rolling bearing using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the positioning sleeve 16.

[0101] Installation of positioning elements (II): Another spindle support ring 17 is oriented and installed on the spindle 13, with its lower end face fitting against the outer end face of the upper inner ring 141 of the right rolling bearing. A retaining ring 15 with its groove facing down is oriented and installed on the spindle 13, with its inner hole fitted onto the outer diameter of the support ring, and the end face of the groove fitting against the upper end face of the outer ring 144 of the right rolling bearing.

[0102] 3.4) Assembly of right eccentric gear 12: The right eccentric gear 12 is heated by temperature difference method. The shaft hole keyway of the right eccentric gear 12 is aligned and oriented with the open through keyway 132 of the main shaft 13. The synchronization between the right eccentric gear 12 and the left eccentric gear 11 is quickly corrected.

[0103] The right eccentric gear 12 is heated using a temperature difference method. The heated left eccentric gear 11 is then lifted to the spindle position using a crane. Debris in the shaft hole is cleaned, and the keyway of the shaft hole of the right eccentric gear 12 is aligned with the open through keyway 132 of the spindle 13 before orientation and installation. Immediately afterwards, the synchronization between the right eccentric gear 12 and the left eccentric gear 11 is quickly corrected using a helical gear precision calibration ruler 20. Specifically, the round steel 201 of the helical gear precision calibration ruler 20 is oriented and placed in the tooth groove near the keyway of the right eccentric gear 12, while the rectangular ruler 202 of the helical gear precision calibration ruler 20 is freely and vertically pointed to the bottom left eccentric gear 11. At this time, the offset of the outer angle and the offset of the inner angle of the helical teeth of the left and right eccentric gears 12 (error values) are immediately measured, and the right eccentric gear 12 is rotated slightly by tapping it with a copper hammer to correct the deviation. Three helical tooth grooves (angles) are measured continuously, one near the keyway and one near the connecting rod pin 19. It should be noted that due to the temperature difference assembly method, the thermal conduction of the right eccentric gear 12 will cause the main shaft 13 to expand due to heat. Therefore, the time window for correction and alignment is extremely short, not exceeding 5 minutes, and is directly related to the ambient temperature inside the workshop.

[0104] 4) Flat key precision measurement and assembly: Measure the offset between the keyway in the shaft hole of the right eccentric gear 12 and the open through keyway 132 on the main shaft 13, and prepare and assemble the flat key.

[0105] Keyway measurement: Half an hour after the right eccentric gear 12 is oriented and assembled, the offset between the keyway of the shaft hole of the right eccentric gear 12 and the open through keyway 132 of the main shaft 13 is measured.

[0106] Flat key preparation: A flat key is fabricated based on the measured offset. At this point, the flat key has a rectangular structure with a left-right offset (see [reference]). Figure 8 The flat key after machining is the offset flat key 182. The rectangular body of the flat key is consistent with the rectangular hole formed by the shaft hole keyway of the right eccentric gear 12 and the open through keyway 132 of the main shaft 13. It should be noted that when the machining accuracy of each component is high, the keyway hole may have no offset or very little equivalent offset.

[0107] Installing the parallel key: Using the residual heat of the right eccentric gear 12, the custom-made parallel key is quickly installed with the semi-circular head facing down, using a copper hammer to install it, and using the temperature difference to enhance the axial positioning stability.

[0108] 5) Assembly accuracy inspection: The synchronization of the left eccentric gear 11 and the right eccentric gear 12 of the driven shaft device, the working clearance of the rolling bearing 14, and the axial clearance are inspected respectively.

[0109] Combination Figure 2 As shown, the assembly accuracy inspection specifically includes:

[0110] 5.1) Synchronization test of left eccentric gear 11 and right eccentric gear 12: After the temperature of left eccentric gear 11 and right eccentric gear 12 returns to normal operating conditions, the synchronization of left eccentric gear 11 and right eccentric gear 12 is tested using a helical gear precision calibration ruler 20. The synchronization accuracy of the helical gears is tested at least three points (the part near the connecting rod pin 19 and the part near the keyway must be tested). The offset a1 of the inner side angle of the helical gear and the offset a2 of the outer side angle of the helical gear are obtained and compared with the standard specified by the technical standard of the helical gear assembly enterprise of this type of driven shaft device (for example, the helical gear assembly standard of the driven shaft device is ≤0.5mm) to determine whether it is qualified: When the offset of the inner side angle and the outer side angle of the helical gear both meet the helical gear assembly standard of the driven shaft device, the synchronization of left eccentric gear 11 and right eccentric gear 12 is qualified; otherwise, it is disassembled and reworked.

[0111] 5.2) Inspection of the working clearance of rolling bearing 14: Use feeler gauges to check the clearance between the outer ring 144 of the two rolling bearings on the main shaft 13 and the rolling element 143 of the upper inner ring 141, i.e., the working clearance inspection b1 and b2 of rolling bearing 14 (b1 is the working clearance of the left rolling bearing and b2 is the working clearance of the right rolling bearing), and compare it with the working clearance standard specified by the technical standard of the assembly enterprise of the rolling bearing 14 of this type of passive shaft device (e.g., the working clearance standard is 0.02~0.10mm) to determine whether it is qualified; when the clearance between the outer ring 144 of the two rolling bearings and the rolling element 143 of the upper inner ring 141 of the two rolling bearings meets the working clearance standard of the rolling bearing 14 of the passive shaft device, the working clearance of rolling bearing 14 is qualified; otherwise, it is disassembled and reworked.

[0112] 5.3) Axial clearance inspection of the driven shaft assembly: Use a 0.05mm feeler gauge to inspect the mating points of each component assembled on the main shaft 13 of the driven shaft assembly, including the eccentric gear and the main shaft support ring 17 (left eccentric gear 11 and the corresponding main shaft support ring 17, right eccentric gear 12 and the corresponding main shaft support ring 17), the main shaft support ring 17 and the inner ring of the rolling bearing 14 (main shaft support ring 17 and the corresponding left rolling bearing inner ring, main shaft support ring 17 and the corresponding right rolling bearing inner ring), and the inner ring of the rolling bearing 14 and the positioning sleeve 16 (left rolling bearing inner ring and positioning sleeve 16, right rolling bearing inner ring and positioning sleeve 16), etc., to ensure that its axial positioning is stable and that there is no gap due to temperature difference or human factors, that is, to ensure that the gap at the mating point of each component is 0. When the gap at any of the mating points of the components assembled on the main shaft 13 of the passive shaft device is not zero, a wheel and axle press can be used to eliminate the gap by axial pressing, so that the gap at the mating points of each component is zero.

[0113] Following the above-described steps, the assembly method for the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill provided by this invention is completed for on-site application. The assembled passive shaft device can be lubricated, coated with anti-rust oil, packaged, and then stored in a warehouse. Alternatively, it can be assembled with left and right connecting rods to form a kit for storage, or it can be used directly on the machine as a complete set. Using the assembly method of this invention, the synchronization error between the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device is ≤0.5mm, and the working clearance of the rolling bearing 14 is controlled between 0.02 and 0.10mm. This meets the technical requirements for the production of cold-rolled seamless steel pipes of high-alloy steel grades such as high-strength, deformation-resistant nickel-based alloys, high-temperature alloys, and duplex stainless steel.

[0114] It should be noted that the installation of the passive shaft device requires high precision and takes a long time. It usually needs to be pre-assembled as a spare part and put into use when the seamless steel pipe cold rolling mill is scheduled for maintenance or emergency repair of sudden failures, so as to reduce the time required for downtime or scheduled maintenance.

[0115] Example 1

[0116] Taking the LG-150H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ110~150mm as an example, its driven shaft uses 351164 double-row short cylindrical roller bearings (old model 2097764). The enterprise technical standard requires its working clearance to be between 0.05~0.08mm, the correction value L2 to be 0.05~0.08mm, and the synchronization error between the left eccentric gear 11 and the right eccentric gear 12 to be ≤1.0mm. Due to planned maintenance, the entire driven shaft device needs to be replaced. Therefore, the driven shaft device components are assembled in advance under offline conditions. The operation process includes: operation preparation → precision calibration of rolling bearing 14 → precision assembly of left eccentric gear 11 and right eccentric gear 12 → flat key measurement and assembly → assembly precision inspection, to ensure that the precision of left eccentric gear 11, right eccentric gear 12 and rolling bearing 14 meets the technical requirements for cold-rolled pipe production.

[0117] Combination Figure 9 As shown in this embodiment, the assembly method of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill includes the following steps:

[0118] 1) Work preparation procedures:

[0119] 1.1) Safety briefing and identification of hazards before operation, implementation and inspection of on-site safety precautions, preparation of tools, equipment and materials, etc.

[0120] 1.2) Clean and sanitize spare parts and materials, and verify the consistency between the drawings and the spare parts and materials to ensure that the quantity and accuracy of the spare parts and materials are correct.

[0121] 1.3) Prepare a measuring ruler 20 for helical gear accuracy calibration, combined with... Figure 6As shown, there is one helical gear precision calibration ruler 20, which has a right-angled structure and is made of 45# medium carbon steel. It is formed by welding round steel 201 and rectangular ruler 202; combined with Figure 6 As shown, the diameter of the round steel 201 should preferably be 0.10 to 0.20 mm smaller than the width of the eccentric gear tooth groove, and its length should preferably be equal to the width of the eccentric gear; the length of the rectangular ruler 202 should preferably be the total width of the passive shaft device formed by the left eccentric gear 11 and the right eccentric gear 12 mounted on the main shaft 13 plus 20 to 30 mm, and its width should be equivalent to the diameter of the round steel 201; one end of the round steel 201 should be welded to either end of the rectangular ruler 202, and the welding angle should be consistent with the eccentric gear inclination being tested, and the surface roughness of each component of the helical gear accuracy calibration ruler 20 should preferably be no less than Ra1.6.

[0122] 1.4) Spindle keyway modification and machining: combined with Figure 5 As shown, the closed keyway 131 on either side of the spindle 13, near the end face of the spindle 13, is machined by a milling machine to form a single-sided open through keyway 132 structure. The original spindle (see...) Figure 4 As shown, the spindle needs to be modified and processed. The drawings for the new spindle 13 can be modified and completed during the spare parts processing.

[0123] 2) Precision calibration of rolling bearing 14 (see...) Figure 3 (As shown)

[0124] 2.1) Bearing measurement preparation: Place the double-row short cylindrical roller bearing on a special platform (working platform 21), remove the bearing support ring 145 between the upper inner ring 141 and the lower inner ring 142, and use a 90-degree square to correct the perpendicularity of the outer ring 144 of the rolling bearing 14.

[0125] 2.2) Measurement of the bearing in its original state: Using vernier calipers or gauge blocks, measure the actual distance between the upper inner ring 141 and the lower inner ring 142, i.e., the width of the original bearing support ring 145. The three readings are 13.15mm, 13.15mm, and 13.17mm. Then, manually rotate the outer ring 144 of the rolling bearing 14 at least three times and measure the width of the bearing support ring 145 again. The three readings are 13.16mm, 13.15mm, and 13.17mm. To ensure measurement accuracy, a weight can be installed on the top end face of the upper inner ring 141 when manually rotating the outer ring 144. The weight should weigh no less than 10kg.

[0126] 2.3) Determine the grinding thickness of the bearing support ring 145: Integrate and correct the actual distance readings between the upper inner ring 141 and the lower inner ring 142, and take their average value, that is, the measured width L of the bearing support ring 145 installed inside the rolling bearing 14 is (13.15+13.15+13.17+13.16+13.15+13.17)÷6=13.158≈13.16mm; According to the accuracy requirements of the 351164 double row short cylindrical roller bearing, calculate the grinding thickness of the bearing support ring 145, and L1=L+L2, where L1 is the required grinding thickness of the bearing support ring 145, L2 is the correction value according to the technical requirements, and its range is 0.05~0.08; L is the measured width of the bearing support ring 145 installed inside the rolling bearing 14. L1 = 13.16 + (0.05 ~ 0.08) = 13.21 ~ 13.24 mm. Take the middle value. The bearing support ring of 145 should be machined to a thickness of L1 = 13.22 mm.

[0127] 2.4) Inspection and confirmation of the working clearance of rolling bearing 14

[0128] Inspection of the working clearance of rolling bearing 14: After grinding, the bearing is oriented and assembled between the upper inner ring 141 and the lower inner ring 142 of rolling bearing 14 using support ring 145. The outer ring 144 of rolling bearing 14 is manually rotated at least three times. The clearance between the rolling element 143 (outer circumferential surface of short cylindrical roller) on the upper inner ring 141 of rolling bearing 14 and the outer ring 144 is measured using a feeler gauge. The readings at three points are 0.06, 0.06, and 0.07 mm.

[0129] Confirmation of working clearance of rolling bearing 14: The clearance value between rolling element 143 on the upper inner ring 141 and outer ring 144 of rolling bearing 14, measured in the previous step, is obtained by integrating the average value method. This clearance value is the actual working clearance value of rolling bearing 14, b = (0.06 + 0.06 + 0.07) ÷ 3 = 0.063 mm. The working clearance equivalent of 0.05 to 0.08 mm specified in the technical requirements is consistent with the measured working clearance b = 0.063 mm, and the inspection is qualified.

[0130] 2.5) Repeat the above steps to complete the accuracy correction of the working clearance (motion clearance) of the two sets of rolling bearings 14. The actual working clearance of the other set of rolling bearings 14 is b≈0.07mm, which meets the technical requirements.

[0131] 3) Eccentric gear assembly (see...) Figure 7 (As shown)

[0132] 3.1) Install the flat key and left eccentric gear 11 on one side of the spindle 13:

[0133] Install one side flat key: Orient the two semi-circular flat keys at both ends and fix them in the closed keyway 131 of the spindle 13. Then, vertically stand the spindle 13 with the flat key installed at the top on the special work station or work platform 21 and clean the outer surface of the spindle 13 and the flat key.

[0134] Assembly of left eccentric gear 11: The left eccentric gear 11 is heated by temperature difference method. The heated left eccentric gear 11 is lifted to the spindle position by lifting machinery. The shaft hole is cleaned of debris. The keyway of the shaft hole of the left eccentric gear 11 is aligned with the flat key on the spindle 13 and then installed in an oriented manner. It is necessary to ensure that the end face of the left eccentric gear 11 is flush with the end face of the spindle 13.

[0135] 3.2) Repositioning of spindle 13: After the left eccentric gear 11 is oriented and installed on the spindle 13, and left to stand in the air for at least five minutes, the spindle 13 and the left eccentric gear 11 are tilted to the side using a crane, so that the left eccentric gear 11 is facing down and the spindle 13 is positioned with the optical axis of the mounting parts facing up (the open through keyway 132 is located at the highest point). The spindle 13 is then vertically placed on a dedicated work station or work platform 21, and the outer circumferential surface of the optical axis of the spindle 13 is cleaned.

[0136] 3.3) Install the components on spindle 13:

[0137] Install positioning elements (I): Install a spindle support ring 17 on the spindle 13 in an orientation, with its lower end face fitting against the inner end face of the left eccentric gear 11. Install a retaining ring 15 on the spindle 13 with its groove facing upward, with its inner hole fitted onto the outer diameter of the spindle support ring 17, and its end face fitting against the left eccentric gear 11.

[0138] Install the left rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the main shaft support ring 17.

[0139] Install positioning sleeve 16: Install positioning sleeve 16 onto spindle 13 in an orientation, with the lower end face of positioning sleeve 16 fitting against the outer end face of the upper inner ring 141 of left rolling bearing 14.

[0140] Install the right rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring should be in contact with the upper end face of the positioning sleeve 16.

[0141] Installation of positioning elements (II): Another spindle support ring 17 is oriented and installed on the spindle 13, with its lower end face fitting against the outer end face of the upper inner ring 141 of the right rolling bearing. A retaining ring 15 is oriented and installed on the spindle 13 with its groove facing down, and its inner hole is fitted onto the outer diameter of the spindle support ring 17. The groove end face of the retaining ring 15 is fitted against the upper end face of the outer ring 144 of the right rolling bearing.

[0142] 3.4) Assembly of the right eccentric gear 12: The right eccentric gear 12 is heated using a temperature difference method. The heated left eccentric gear 11 is then lifted to the spindle position using a lifting machine. Debris in the shaft hole is cleaned, and the keyway in the shaft hole is aligned with the open through keyway 132 of the spindle 13 before orientation and installation. Immediately afterwards, a helical gear precision calibration gauge 20 is used to quickly calibrate the synchronization between the right eccentric gear 12 and the left eccentric gear 11, i.e.: combining... Figure 7 As shown, the round steel 201 of the helical gear precision calibration ruler 20 is oriented and placed in the tooth groove near the keyway of the right eccentric gear 12. The rectangular ruler 202 of the helical gear precision calibration ruler 20 is freely and vertically pointed to the bottom left eccentric gear 11. At this time, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the keyway is measured to be 1.2mm clockwise. The right eccentric gear 12 is then tapped with a copper hammer to rotate slightly counterclockwise to correct the offset. Then, the helical gear precision calibration ruler 20 is moved to measure the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the connecting rod pin 19 to be 0.9mm counterclockwise. The offset is then corrected by hammering with a copper hammer in a clockwise direction. Finally, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 at the middle of the eccentricity is measured to be 0.8mm clockwise. The offset is then corrected by hammering with a copper hammer in a counterclockwise direction. The on-site installation and correction work is completed within 4 minutes.

[0143] 4) Flat key precision measurement assembly

[0144] Keyway measurement: Half an hour after the right eccentric gear 12 is oriented and assembled, the offset between the keyway of the shaft hole of the right eccentric gear 12 and the open through keyway 132 of the main shaft 13 is measured; the keyway of the eccentric gear shaft hole and the main shaft keyway are measured to be offset counterclockwise by 0.10mm.

[0145] Key fabrication: Based on the measured offset of 0.10mm counterclockwise, a flat key is machined. At this point, the flat key has a rectangular structure offset to the left and right, meaning the rectangular body at the eccentric gear end and the rectangular body of the main shaft 13 shaft hole section are offset counterclockwise by 0.10mm (see...). Figure 8 (as shown in (c)).

[0146] Installing the parallel key: Using the residual heat of the right eccentric gear 12, the custom-made parallel key is quickly installed with the semi-circular head facing down, using a copper hammer to install it, and using the temperature difference to enhance the axial positioning stability.

[0147] 5) Assembly accuracy inspection (see...) Figure 2 (As shown)

[0148] 5.1) Synchronization test of left eccentric gear 11 and right eccentric gear 12: After the temperature of left eccentric gear 11 and right eccentric gear 12 returns to normal operating conditions, the helical gear precision calibration gauge 20 is still used to continuously measure the connecting rod pin 19, keyway, and eccentric middle part. The outer helical gear angle readings are 0.8mm, 0.6mm, and 0.9mm counterclockwise, and the inner helical gear angle readings are 0.7mm, 0.7mm, and 0.5mm counterclockwise. After integration and correction, the offset of the outer helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is determined to be a1 = counterclockwise (0.8 + 0.6 + 0.9) ÷ 3 = 0.77 mm, and the inner helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is a2 = counterclockwise (0.7 + 0.7 + 0.5) ÷ 3 = 0.63 mm. The eccentric gear helical angles a1 and a2 are both ≤ 1.0 mm, which meets the technical requirements and the assembly is qualified.

[0149] 5.2) Inspection of working clearance of rolling bearing 14: The working clearance of the two sets of short cylindrical roller bearings is inspected using feeler gauges, namely the clearance values ​​b1 = 0.06 mm and b2 = 0.05 mm between the outer ring 144 of the bearing and the outer circumferential surface of the rolling element 143 of the upper inner ring 141 installed on the inner side (both ends of the positioning sleeve 16). The clearance is compared with the technical standard of 0.05 to 0.08 mm of the rolling bearing 14 of this type of passive shaft device by the assembly enterprise. It is confirmed that the clearance is in compliance and the assembly is qualified.

[0150] 5.3) Axial clearance inspection: Using a 0.05mm feeler gauge, check the axial contact parts (contact surfaces) of each component of the driven shaft assembly, including: the eccentric gear and the main shaft support ring 17, the main shaft support ring 17 and the inner ring of the rolling bearing 14, and the inner ring of the rolling bearing 14 and the positioning sleeve 16. There is no axial clearance, and the assembly is qualified.

[0151] Example 2

[0152] Taking the LG-110H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ76~110mm as an example, its driven shaft uses 351150 double-row short cylindrical roller bearings (old model 2097750). The enterprise technical standard requires its working clearance to be between 0.03~0.06mm, the correction value L2 to be 0.03~0.06mm, and the synchronization error of the left and right eccentric gears 12 to be ≤1.0mm. Due to planned maintenance, the entire driven shaft device needs to be replaced. Therefore, the driven shaft device components are assembled in advance under offline conditions. The operation process includes: operation preparation → precision calibration of rolling bearing 14 → precision assembly of left eccentric gear 11 and right eccentric gear 12 → flat key measurement and assembly → assembly precision inspection, to ensure that the precision of left eccentric gear 11, right eccentric gear 12 and rolling bearing 14 meets the technical requirements of cold-rolled pipe.

[0153] Combination Figure 9 As shown in this embodiment, the assembly method of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill includes the following steps:

[0154] 1) Work preparation procedures:

[0155] 1.1) Safety briefing and identification of hazards before operation, implementation and inspection of on-site safety precautions, preparation of tools, equipment and materials, etc.

[0156] 1.2) Clean and sanitize spare parts and materials, and verify the consistency between the drawings and the spare parts and materials to ensure that the quantity and accuracy of the spare parts and materials are correct.

[0157] 1.3) Prepare a measuring ruler 20 for helical gear accuracy calibration, combined with... Figure 6 As shown, there is one helical gear precision calibration ruler 20, which has a right-angled structure and is made of 45# medium carbon steel. It is formed by welding round steel 201 and rectangular ruler 202; combined with Figure 6 As shown, the diameter of the round steel 201 should preferably be 0.10 to 0.20 mm smaller than the width of the eccentric gear tooth groove, and its length should preferably be equal to the width of the eccentric gear; the length of the rectangular ruler 202 should preferably be the total width of the passive shaft device formed by the left eccentric gear 11 and the right eccentric gear 12 mounted on the main shaft 13 plus 20 to 30 mm, and its width should be equivalent to the diameter of the round steel 201; one end of the round steel 201 should be welded to either end of the rectangular ruler 202, and the welding angle should be consistent with the eccentric gear inclination being measured, and the surface roughness of each component of the measuring ruler 20 should preferably be no less than Ra1.6.

[0158] 1.4) Spindle keyway modification and machining: combined with Figure 5 As shown, the closed keyway 131 on either side of the spindle 13, near the end face of the spindle 13, is machined by a milling machine to form a single-sided open through keyway 132 structure. The original spindle (see...) Figure 4 As shown, the spindle needs to be modified and processed. The drawings for the new spindle 13 can be modified and completed during the spare parts processing.

[0159] 2) Precision calibration of rolling bearing 14 (see...) Figure 3 (As shown)

[0160] 2.1) Bearing measurement preparation: Place the double-row short cylindrical roller bearing on a special platform (working platform 21), remove the bearing support ring 145 between the upper inner ring 141 and the lower inner ring 142, and use a 90-degree square to correct the perpendicularity of the outer ring 144 of the rolling bearing 14.

[0161] 2.2) Measurement of the bearing in its original state: Using vernier calipers or gauge blocks, measure the actual distance between the upper inner ring 141 and the lower inner ring 142, i.e., the width of the original bearing support ring 145. The three readings are 12.20mm, 12.21mm, and 12.21mm. Then, manually rotate the outer ring 144 of the rolling bearing 14 at least three times and measure the width of the bearing support ring 145 again. The three readings are 12.21mm, 12.22mm, and 12.21mm. To ensure measurement accuracy, a weight can be installed on the top end face of the upper inner ring 141 when manually rotating the outer ring 144. The weight should weigh no less than 10kg.

[0162] 2.3) Determine the grinding thickness of the bearing support ring 145: Integrate and correct the actual distance readings between the upper inner ring 141 and the lower inner ring 142, and take their average value, that is, the measured width L of the bearing support ring 145 installed inside the rolling bearing 14 is (12.20+12.21+12.21+12.21+12.22+12.21)÷6≈12.21mm; According to the accuracy requirements of the 351150 double row short cylindrical roller bearing, calculate the grinding thickness of the bearing support ring 145, that is, L1=L+L2, where L1 is the required grinding thickness of the bearing support ring 145, L2 is the correction value according to the technical requirements, and its range is 0.03~0.06; L is the measured thickness value of the bearing support ring 145 installed inside the rolling bearing 14. L1 = 12.21 + (0.03 ~ 0.06) = 13.24 ~ 13.27 mm. Take the middle value. The bearing support ring of 145 should be machined to a thickness of L1 = 12.25 mm.

[0163] 2.4) Inspection and confirmation of the working clearance of rolling bearing 14

[0164] Inspection of the working clearance of rolling bearing 14: After grinding, the support ring is oriented and assembled between the upper inner ring 141 and the lower inner ring 142 of rolling bearing 14. The outer ring 144 of rolling bearing 14 is manually rotated at least three times. The clearance between the rolling element 143 (outer circumferential surface of the short cylindrical roller) on the upper inner ring 141 of rolling bearing 14 and the outer ring 144 is measured with a feeler gauge. The readings at three points are 0.04mm, 0.05mm and 0.04mm.

[0165] Confirmation of working clearance of rolling bearing 14: The clearance value between rolling element 143 on the upper inner ring 141 and outer ring 144 of rolling bearing 14, measured in the previous step, is obtained by integrating the average value method. This clearance value is the actual working clearance value of rolling bearing 14, b = (0.04 + 0.05 + 0.04) ÷ 3 = 0.043 mm. The working clearance equivalent of 0.03 to 0.06 mm specified in the technical requirements is consistent with the measured working clearance b = 0.063 mm, and the inspection is qualified.

[0166] 2.5) Repeat the above steps to complete the accuracy correction of the working clearance (motion clearance) of the two sets of rolling bearings 14. The actual working clearance of the other set of rolling bearings 14 is b≈0.05mm, which meets the technical requirements.

[0167] 3) Eccentric gear assembly (see...) Figure 7 (As shown)

[0168] 3.1) Install the flat key and left eccentric gear 11 on one side of the spindle 13:

[0169] Install one side flat key: Orient the two semi-circular flat keys at both ends and fix them in the closed keyway 131 of the spindle 13. Then, vertically stand the spindle 13 with the flat key installed at the top on the special work station or work platform 21 and clean the outer surface of the spindle 13 and the flat key.

[0170] Assembly of left eccentric gear 11: The left eccentric gear 11 is heated by temperature difference method. The heated left eccentric gear 11 is lifted to the spindle position by lifting machinery. The shaft hole is cleaned of debris. The keyway of the shaft hole of the left eccentric gear 11 is aligned with the flat key on the spindle 13 and then installed in an oriented manner. It is necessary to ensure that the end face of the eccentric gear is flush with the end face of the spindle 13.

[0171] 3.2) Repositioning of spindle 13: After the left eccentric gear 11 is oriented and installed on the spindle 13, and left to stand in the air for at least five minutes, the spindle 13 and the left eccentric gear 11 are tilted to the side using a crane, so that the left eccentric gear 11 is facing down and the spindle 13 is positioned with the optical axis of the mounting parts facing up (the open through keyway 132 is located at the highest point). The spindle 13 is then vertically placed on a dedicated work station or work platform 21, and the outer circumferential surface of the optical axis of the spindle 13 is cleaned.

[0172] 3.3 Installing components on spindle 13:

[0173] Install positioning elements (I): Install a spindle support ring 17 on the spindle 13 in an orientation, with its lower end face fitting against the inner end face of the left eccentric gear 11. Install a retaining ring 15 on the spindle 13 with its groove facing upward, with its inner hole fitted onto the outer diameter of the spindle support ring 17, and its end face fitting against the left eccentric gear 11.

[0174] Install the left rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the main shaft support ring 17.

[0175] Install positioning sleeve 16: Install positioning sleeve 16 onto spindle 13 in an orientation, with the lower end face of positioning sleeve 16 fitting against the outer end face of the upper inner ring 141 of the left rolling bearing.

[0176] Install the right rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the positioning sleeve 16.

[0177] Installation of positioning elements (II): Another spindle support ring 17 is oriented and installed on the spindle 13, with its lower end face fitting against the outer end face of the upper inner ring 141 of the right rolling bearing. A retaining ring 15 is oriented and installed on the spindle 13 with its groove facing down, and its inner hole is fitted onto the outer diameter of the spindle support ring 17. The groove end face of the retaining ring 15 is fitted against the upper end face of the outer ring 144 of the rolling bearing 14.

[0178] 3.4) Assembly of the right eccentric gear 12: The right eccentric gear 12 is heated using a temperature difference method. The heated left eccentric gear 11 is then lifted to the spindle position using a lifting machine. Debris in the shaft hole is cleaned, and the keyway in the shaft hole is aligned with the open through keyway 132 of the spindle 13 before orientation and installation. Immediately afterwards, a helical gear precision calibration gauge 20 is used to quickly calibrate the synchronization between the right eccentric gear 12 and the left eccentric gear 11, i.e.: combining... Figure 7 As shown, the round steel 201 of the helical gear precision calibration ruler 20 is oriented and placed in the tooth groove near the keyway of the right eccentric gear 12. The rectangular ruler 202 of the helical gear precision calibration ruler 20 is freely and vertically pointed to the bottom left eccentric gear 11. At this time, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the keyway is measured to be 1.5mm counterclockwise. The right eccentric gear 12 is then tapped with a copper hammer to rotate slightly counterclockwise to correct the offset. Then, the helical gear precision calibration ruler 20 is moved to measure the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the connecting rod pin 19, which is 1.2mm clockwise. The offset is then hammered clockwise with a copper hammer to correct the offset. Finally, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 at the middle of the eccentricity is measured to be 0.7mm counterclockwise. The offset is then hammered counterclockwise with a copper hammer to correct the offset. The on-site installation and correction work is completed within 5 minutes.

[0179] 4) Flat key precision measurement assembly

[0180] Keyway measurement: Half an hour after the right eccentric gear 12 is oriented and assembled, the offset between the keyway of the shaft hole of the right eccentric gear 12 and the open through keyway 132 of the main shaft 13 is measured; the keyway of the eccentric gear shaft hole and the main shaft keyway are measured to be offset clockwise by 0.20mm.

[0181] Key fabrication: Based on the measured offset of 0.20mm counterclockwise, a flat key is machined. At this point, the flat key has a rectangular structure offset to the left and right, meaning the rectangular body at the eccentric gear end and the rectangular body of the spindle 13 shaft hole section are offset clockwise by 0.20mm (see...). Figure 8 (as shown in (c)).

[0182] Installing the parallel key: Using the residual heat of the right eccentric gear 12, the custom-made parallel key is quickly installed with the semi-circular head facing down, using a copper hammer to install it, and using the temperature difference to enhance the axial positioning stability.

[0183] 5) Assembly accuracy inspection (see...) Figure 2 (As shown)

[0184] 5.1) Synchronization accuracy inspection of left eccentric gear 11 and right eccentric gear 12: After the temperature of left eccentric gear 11 and right eccentric gear 12 returns to normal operating conditions, the helical gear accuracy calibration gauge 20 is still used to continuously measure the connecting rod pin 19, keyway, and eccentric middle part. The outer helical gear outer angle readings are 0.7mm, 0.6mm, and 0.8mm clockwise, and the inner helical gear inner angle readings are 0.5mm, 0.6mm, and 0.8mm clockwise. After integration and correction, the offset of the outer helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is determined to be a1 = clockwise (0.7 + 0.6 + 0.8) ÷ 3 = 0.7 mm, and the inner helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is a2 = clockwise (0.5 + 0.6 + 0.8) ÷ 3 = 0.63 mm. The eccentric gear helical angles a1 and a2 are both ≤ 1.0 mm, which meets the technical requirements and the assembly is qualified.

[0185] 5.2) Inspection of working clearance of rolling bearing 14: The working clearance of the two sets of short cylindrical roller bearings is inspected using feeler gauges, namely the clearance values ​​b1 = 0.4 mm and b2 = 0.05 mm between the outer ring 144 of the bearing and the outer circumferential surface of the rolling element 143 of the upper inner ring 141 installed on the inner side (both ends of the positioning sleeve 16). The clearance is compared with the technical standard of 0.03 to 0.06 mm of the rolling bearing 14 of this type of passive shaft device by the assembly enterprise. It is confirmed that the clearance is in compliance and the assembly is qualified.

[0186] 5.3) Axial clearance inspection: Use a 0.05mm feeler gauge to check the axial contact parts (contact surfaces) of each component of the driven shaft device, including: there is no clearance between the eccentric gear and the main shaft support ring 17, and between the main shaft support ring 17 and the inner ring of the rolling bearing 14, but there is a 0.25mm clearance between the inner ring of the rolling bearing 14 and the positioning sleeve 16, which is unqualified for assembly.

[0187] Axial clamping is used to eliminate the gap: A wheel-axle type press is used to press the eccentric gear on the side with the gap, and the pressure is set to 50 tons equivalent for clamping.

[0188] Re-inspection: The clearance between the inner ring of the rolling bearing 14 and the locating sleeve 16 was checked using a 0.05mm feeler gauge, and then the working clearance of the rolling bearing 14 at this location was re-measured. After measurement, the clearance between the inner ring of the rolling bearing 14 and the locating sleeve 16 was eliminated, and the working clearance b of the rolling bearing 14 was 0.03mm, which meets the technical requirements. The re-inspection showed that the assembly was qualified.

[0189] Example 3

[0190] Taking the LG-60H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ38~60mm as an example, its driven shaft uses 351136 double-row short cylindrical roller bearings (old model 2097736). The enterprise technical standard requires its working clearance to be between 0.02~0.05mm, the correction value L2 to be 0.03~0.06mm, and the synchronization error between the left eccentric gear 11 and the right eccentric gear 12 to be ≤0.8mm. Due to planned maintenance, the entire driven shaft device needs to be replaced. Therefore, the driven shaft device components are assembled in advance under offline conditions. The operation process includes: operation preparation → precision calibration of rolling bearing 14 → precision assembly of left eccentric gear 11 and right eccentric gear 12 → flat key measurement and assembly → assembly precision inspection, to ensure that the precision of left eccentric gear 11, right eccentric gear 12 and rolling bearing 14 meets the technical requirements for cold-rolled pipe production.

[0191] Combination Figure 9 As shown in the figure, the assembly method of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill provided in this embodiment includes the following steps:

[0192] 1) Work preparation procedures:

[0193] 1.1) Safety technical briefing and identification of hazardous factors before operation, implementation and inspection of on-site safety precautions, preparation of tools, equipment and materials, etc.

[0194] 1.2) Clean and sanitize spare parts and materials, and verify the consistency between the drawings and the spare parts and materials to ensure that the quantity and accuracy of the spare parts and materials are correct.

[0195] 1.3) Prepare a measuring ruler 20 for helical gear accuracy calibration, combined with... Figure 6 As shown, there is one helical gear precision calibration ruler 20, which has a right-angled structure and is made of 45# medium carbon steel. It is formed by welding round steel 201 and rectangular ruler 202; combined with Figure 6As shown, the diameter of the round steel 201 should preferably be 0.10 to 0.20 mm smaller than the width of the eccentric gear tooth groove, and its length should preferably be equal to the width of the eccentric gear; the length of the rectangular ruler 202 should preferably be the total width of the passive shaft device formed by the left eccentric gear 11 and the right eccentric gear 12 mounted on the main shaft 13 plus 20 to 30 mm, and its width should be equivalent to the diameter of the round steel 201; one end of the round steel 201 should be welded to either end of the rectangular ruler 202, and the welding angle should be consistent with the eccentric gear inclination being measured, and the surface roughness of each component of the measuring ruler 20 should preferably be no less than Ra1.6.

[0196] 1.4) Spindle keyway modification and machining: combined with Figure 5 As shown, the closed keyway 131 on either side of the spindle 13, near the end face of the spindle 13, is machined by a milling machine to form a single-sided open through keyway 132 structure. The original spindle (see...) Figure 4 As shown, the spindle needs to be modified and processed. The drawings for the new spindle 13 can be modified and completed during the spare parts processing.

[0197] 2) Rolling bearing 14 precision calibration (see Figure 3 (As shown)

[0198] 2.1) Bearing measurement preparation: Place the double-row short cylindrical roller bearing on a special platform (working platform 21), remove the bearing support ring 145 between the upper inner ring 141 and the lower inner ring 142, and use a 90-degree square to correct the perpendicularity of the outer ring 144 of the rolling bearing 14.

[0199] 2.2) Measurement of the bearing in its original state: Using vernier calipers or gauge blocks, measure the actual distance between the upper inner ring 141 and the lower inner ring 142, i.e., the width of the original bearing support ring 145. The three readings are 10.80mm, 10.79mm, and 10.81mm. Then, manually rotate the outer ring 144 of the rolling bearing 14 at least three times and measure the actual distance between the upper inner ring 141 and the lower inner ring 142 again. The three readings are 10.81mm, 10.82mm, and 10.81mm. To ensure measurement accuracy, a weight of not less than 10kg should be installed on the top end face of the upper inner ring 141 when manually rotating the outer ring 144.

[0200] 2.3) Determine the grinding thickness of the bearing support ring 145: Integrate and correct the actual distance readings between the upper inner ring 141 and the lower inner ring 142, and take their average value. That is, the measured width L of the bearing support ring 145 installed inside the rolling bearing 14 is (10.80+10.79+10.81+10.81+10.82+10.81)÷6=10.806≈10.81mm; According to the accuracy requirements of the 351164 double-row short cylindrical roller bearing, calculate the grinding thickness of the bearing support ring 145, that is, L1=L+L2, where L1 is the required grinding thickness of the bearing support ring 145, L2 is the correction value according to the technical requirements, and its range is 0.02~0.05; L is the measured thickness value of the bearing support ring 145 installed inside the rolling bearing 14. L1 = 10.81 + (0.02 ~ 0.05) = 10.83 ~ 10.86 mm. Take the middle value. The bearing support ring of 145 should be machined to a thickness of L1 = 10.84 mm.

[0201] 2.4) Inspection and confirmation of the working clearance of rolling bearing 14

[0202] Inspection of the working clearance of rolling bearing 14: After grinding, the support ring is oriented and assembled between the upper inner ring 141 and the lower inner ring 142 of rolling bearing 14. The outer ring 144 of rolling bearing 14 is manually rotated at least three times. The clearance between the rolling element 143 (outer circumferential surface of the short cylindrical roller) on the upper inner ring 141 of rolling bearing 14 and the outer ring 144 is measured with a feeler gauge. The readings at three points are 0.03mm, 0.04mm and 0.03mm.

[0203] Confirmation of working clearance of rolling bearing 14: The clearance value between rolling element 143 on the upper inner ring 141 and outer ring 144 of rolling bearing 14, measured in the previous step, is obtained by integrating the average value method. This clearance value is the actual working clearance value of rolling bearing 14, b = (0.04 + 0.03 + 0.04) ÷ 3 = 0.037 mm. The working clearance equivalent of 0.02 to 0.05 mm specified in the technical requirements is consistent with the measured working clearance b = 0.037 mm, and the inspection is qualified.

[0204] 2.5) Repeat the above steps to complete the accuracy correction of the working clearance (motion clearance) of the two sets of rolling bearings 14. The actual working clearance of the other set of rolling bearings 14 is b≈0.04mm, which meets the technical requirements.

[0205] 3) Eccentric gear assembly (see...) Figure 7 (As shown)

[0206] 3.1) Install the flat key and left eccentric gear 11 on one side of the spindle 13:

[0207] Install one side flat key: Orient the two semi-circular flat keys at both ends and fix them in the closed keyway 131 of the spindle 13. Then, vertically stand the spindle 13 with the flat key installed at the top on the special work station or work platform 21 and clean the outer surface of the spindle 13 and the flat key.

[0208] Assembly of left eccentric gear 11: The left eccentric gear 11 is heated by temperature difference method. The heated left eccentric gear 11 is lifted to the spindle position by lifting machinery. The shaft hole is cleaned of debris. The keyway of the shaft hole of the left eccentric gear 11 is aligned with the flat key on the spindle 13 and then installed in an oriented manner. It is necessary to ensure that the end face of the eccentric gear is flush with the end face of the spindle 13.

[0209] 3.2) Repositioning of spindle 13: After the left eccentric gear 11 is oriented and installed on the spindle 13, and left to stand in the air for at least five minutes, the spindle 13 and the left eccentric gear 11 are tilted to the side using a crane, so that the left eccentric gear 11 is facing down and the spindle 13 is positioned with the optical axis of the mounting parts facing up (the open through keyway 132 is located at the highest point). The spindle 13 is then vertically placed on a dedicated work station or work platform 21, and the outer circumferential surface of the optical axis of the spindle 13 is cleaned.

[0210] 3.3 Installing components on spindle 13:

[0211] Install positioning elements (I): Install a spindle support ring 17 on the spindle 13 in an orientation, with its lower end face fitting against the inner end face of the left eccentric gear 11. Install a retaining ring 15 on the spindle 13 with its groove facing upward, with its inner hole fitted onto the outer diameter of the spindle support ring 17, and its end face fitting against the left eccentric gear 11.

[0212] Install the left rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the main shaft support ring 17.

[0213] Install positioning sleeve 16: Install positioning sleeve 16 onto spindle 13 in an orientation, with the lower end face of positioning sleeve 16 fitting against the outer end face of the upper inner ring 141 of the left rolling bearing.

[0214] Install the right rolling bearing: Heat the rolling bearing 14 using the temperature difference method, and install it on the main shaft 13 in the following order: lower inner ring 142, outer ring 144, bearing support ring 145, and upper inner ring 141. The outer end face of the lower inner ring 142 should be in contact with the upper end face of the positioning sleeve 16.

[0215] Installation of positioning elements (II): Another spindle support ring 17 is oriented and installed on the spindle 13, with its lower end face fitting against the outer end face of the upper inner ring 141 of the right rolling bearing. A retaining ring 15 is oriented and installed on the spindle 13 with its groove facing down, and its inner hole is fitted onto the outer diameter of the spindle support ring 17. The groove end face of the retaining ring 15 is fitted against the upper end face of the outer ring 144 of the rolling bearing 14.

[0216] 3.4) Assembly of the right eccentric gear 12: The right eccentric gear 12 is heated using a temperature difference method. The heated left eccentric gear 11 is then lifted to the spindle position using a lifting machine. Debris in the shaft hole is cleaned, and the keyway in the shaft hole is aligned with the open through keyway 132 of the spindle 13 before orientation and installation. Immediately afterwards, a helical gear precision calibration gauge 20 is used to quickly calibrate the synchronization between the right eccentric gear 12 and the left eccentric gear 11, i.e.: combining... Figure 7 As shown, the round steel 201 of the helical gear precision calibration ruler 20 is oriented and placed in the tooth groove near the keyway of the right eccentric gear 12. The rectangular ruler 202 of the helical gear precision calibration ruler 20 is freely and vertically pointed to the bottom left eccentric gear 11. At this time, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the keyway is measured to be 1.2mm clockwise. The right eccentric gear 12 is then tapped with a copper hammer to rotate slightly counterclockwise to correct the offset. Then, the helical gear precision calibration ruler 20 is moved to measure the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 near the connecting rod pin 19, which is 0.8mm counterclockwise. The offset is then hammered clockwise with a copper hammer to correct the offset. Finally, the offset of the outer and inner angles of the helical teeth of the left eccentric gear 11 and the right eccentric gear 12 at the middle of the eccentricity is measured to be 0.4mm clockwise. The offset is then hammered counterclockwise with a copper hammer to correct the offset. The on-site installation and correction work is completed within 5 minutes.

[0217] 4) Flat key precision measurement assembly

[0218] Keyway measurement: Half an hour after the right eccentric gear 12 is oriented and assembled, the offset between the keyway of the shaft hole of the right eccentric gear 12 and the open through keyway 132 of the main shaft 13 is measured; the keyway of the eccentric gear shaft hole and the main shaft keyway are measured to be offset clockwise by 0.10mm.

[0219] Key fabrication: Based on the measured offset of 0.10mm clockwise, a flat key is machined. At this point, the flat key has a rectangular structure offset to the left and right, meaning the rectangular body at the eccentric gear end and the rectangular body of the main shaft 13 shaft hole section are offset clockwise by 0.10mm (see...). Figure 8 (as shown in (c)).

[0220] Installing the parallel key: Using the residual heat of the right eccentric gear 12, the custom-made parallel key is quickly installed with the semi-circular head facing down, using a copper hammer to install it, and using the temperature difference to enhance the axial positioning stability.

[0221] 5) Assembly accuracy inspection (see...) Figure 2 (As shown)

[0222] 5.1) Synchronization accuracy inspection of left eccentric gear 11 and right eccentric gear 12: After the temperature of left eccentric gear 11 and right eccentric gear 12 returns to normal operating conditions, the helical gear accuracy calibration gauge 20 is still used to continuously measure the connecting rod pin 19, keyway, and eccentric middle part. The outer helical gear outer angle readings are 0.4mm, 0.5mm, and 0.5mm counterclockwise, and the inner helical gear inner angle readings are 0.4mm, 0.3mm, and 0.3mm counterclockwise. After integration and correction, the offset of the outer helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is determined to be a1 = counterclockwise (0.4 + 0.5 + 0.5) ÷ 3 = 0.47 mm, and the inner helical tooth angle of the left eccentric gear 11 and the right eccentric gear 12 is a2 = counterclockwise (0.4 + 0.3 + 0.3) ÷ 3 = 0.33 mm. The eccentric gear helical angles a1 and a2 are both ≤ 0.8 mm, which meets the technical requirements and the assembly is qualified.

[0223] 5.2) Inspection of working clearance of rolling bearing 14: Use feeler gauges to inspect the working clearance of the two sets of short cylindrical roller bearings, namely the clearance values ​​b1 = 0.03mm and b2 = 0.03mm between the outer ring 144 of the bearing and the outer circumferential surface of the rolling element 143 of the upper inner ring 141 installed on the inner side (both ends of the positioning sleeve 16); compare with the technical standard of the assembly company for the rolling bearing 14 of this type of passive shaft device, which is 0.02 to 0.05mm, and confirm that it meets the requirements and the assembly is qualified.

[0224] 5.3) Axial clearance inspection: Using a 0.05mm feeler gauge, check the axial contact parts (contact surfaces) of each component of the driven shaft device, including: the eccentric gear and the support ring, the support ring and the inner ring of the rolling bearing 14, and the inner ring of the rolling bearing 14 and the positioning sleeve 16. There is no axial clearance, and the assembly is qualified.

[0225] In summary, the assembly method of the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill is a technical improvement on the operation and maintenance methods of the existing two-roll periodic seamless steel pipe cold rolling mill main drive mechanism. The tooling design is reasonable, easy to use, and the eccentric gear installation accuracy is high. The testing and fitting method is reasonable, the operation is convenient, and the rolling bearing working clearance is precise and reliable. While ensuring the accuracy of the passive shaft device installation on the machine, it meets the technical requirements for cold rolling of high-alloy, high-strength new steel grades of seamless steel pipes. It is practical, efficient, safe, reliable, and ensures stable and controlled quality. By using a helical gear precision calibration gauge, the eccentric gear precision calibration is achieved during temperature difference-based directional assembly operations, with a synchronization error value ≤0.5mm. Optimization of the keyway structure at one end of the main shaft, with a single-sided open through-slot, allows for precise customization of the keyway after eccentric gear calibration, providing structural assurance for eccentric gear precision calibration. Gauge block measurement, function calculation, and support ring grinding ensure that the rolling bearing working clearance is controlled within the range of 0.02~0.10mm, meeting the company's technical standards. This reduces the radial runout of the driven shaft, increases load-bearing capacity, and extends service life. Field production practice has proven that this effectively improves the operating accuracy and stability of the main drive mechanism, extends the service life of the driven shaft, reduces equipment downtime and maintenance resource consumption, and has a certain effect on cost reduction and production promotion, generating economic benefits of over 500,000 yuan annually. It has strong versatility and offers valuable reference and application for the technical improvement of the main drive mechanism of a two-roll periodic seamless steel pipe cold rolling mill.

[0226] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for assembling the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill, characterized in that, Includes the following steps: (1) Preparation of work: preparation of materials and preparation of precision calibration gauge for helical gears and modification of spindle keyway; (2) Rolling bearing precision calibration: Remove the bearing support ring of the rolling bearing, calibrate the condition of the rolling bearing, obtain the grinding thickness of the bearing support ring, grind and align the bearing support ring to ensure that the working clearance of the rolling bearing is qualified. The rolling bearing accuracy correction further includes: (2.1) Bearing measurement preparation: Place the rolling bearing vertically on the work platform, remove the bearing support ring between the upper inner ring and the lower inner ring of the rolling bearing, and correct the perpendicularity of the outer ring of the rolling bearing. (2.2) Measurement of the original state of the bearing: Measure and record the actual distance between the upper inner ring and the lower inner ring of the rolling bearing, manually rotate the outer ring of the rolling bearing, and measure and record the actual distance between the upper inner ring and the lower inner ring of the rolling bearing again. (2.3) Determine the grinding thickness of the bearing support ring: Calculate the grinding thickness of the bearing support ring based on the actual distance between the upper inner ring and the lower inner ring of the rolling bearing and the accuracy requirements of the rolling bearing. (2.4) Inspection and confirmation of working clearance of rolling bearing: After grinding, the bearing is assembled between the upper inner ring and the lower inner ring of the rolling bearing using a support ring. The outer ring of the rolling bearing is manually rotated, and the clearance between the rolling element on the upper inner ring and the outer ring is measured and recorded. The actual working clearance of the rolling bearing is calculated. If the actual working clearance is within the equivalent working clearance of the rolling bearing, the working clearance of the rolling bearing is qualified. (2.5) Repeat the above steps to complete the precision calibration of the two sets of rolling bearings; (3) Precision assembly of left and right eccentric gears: The left eccentric gear on one side of the closed keyway of the spindle is assembled using the temperature difference method. The components between the left and right eccentric gears of the driven shaft device are assembled sequentially and oriented. Then, the right eccentric gear is assembled using the temperature difference method, and the synchronization between the right and left eccentric gears is quickly corrected. The precision assembly of the left eccentric gear and the right eccentric gear further includes: (3.1) Install the flat key and left eccentric gear on one side of the spindle: Orient the flat key in the closed keyway of the spindle, and use the temperature difference method to orient the left eccentric gear on one side of the closed keyway of the spindle so that the end face of the left eccentric gear is flush with the end face of the spindle. (3.2) Spindle repositioning: Turn the spindle with the left eccentric gear on its side so that the left eccentric gear is facing down and the open through keyway side of the spindle is facing up, and place it vertically on the work station; (3.3) Install the components on the spindle: Install the positioning element, left rolling bearing, positioning sleeve, right rolling bearing, and positioning element sequentially and orientably on the spindle; (3.4) Right eccentric gear assembly: The right eccentric gear is heated by temperature difference method, and the shaft hole keyway of the right eccentric gear is aligned with the open through keyway of the main shaft for orientation assembly, and the synchronization of the right eccentric gear and the left eccentric gear is quickly corrected. (4) Flat key precision measurement and assembly: Measure the offset between the shaft hole keyway of the right eccentric gear and the open through keyway on the main shaft, and prepare and assemble the flat key; (5) Assembly accuracy inspection: The synchronicity of the left and right eccentric gears of the driven shaft assembly, the working clearance of the rolling bearings, and the axial clearance are inspected respectively. The assembly accuracy inspection further includes: (5.1) Synchronization test of left eccentric gear and right eccentric gear: The synchronization of left eccentric gear and right eccentric gear is tested, the offset of the inner side angle and outer side angle of helical gear is obtained, and it is compared with the helical gear assembly standard of the driven shaft device to determine whether it is qualified. (5.2) Inspection of working clearance of rolling bearings: Check the clearance between the outer ring of the two rolling bearings on the main shaft and the upper inner ring rolling element on its inner side, and compare it with the working clearance standard of the rolling bearing of the driven shaft device to determine whether it is qualified. (5.3) Axial clearance inspection of the passive shaft device: Use feeler gauges to inspect the mating points of each component assembled on the main shaft of the passive shaft device to ensure that the clearance of each component mating point is 0.

2. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 1, characterized in that: In step (1), the work preparation includes safety technical briefing, implementation of on-site safety precautions, preparation of tooling and spare parts materials, cleaning of spare parts materials and verification of drawings, preparation of helical gear precision calibration ruler, and modification of passive shaft device spindle keyway.

3. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 2, characterized in that, The helical gear precision calibration gauge has a right-angled structure, which is formed by welding a round steel bar and a rectangular ruler; one end of the round steel bar is welded to one end of the rectangular ruler, and the welding angle is consistent with the helix angle of the eccentric gear of the driven shaft device; the surface roughness of the helical gear precision calibration gauge is not less than R. a 1.

6.

4. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 2, characterized in that, In the modified passive shaft device, the closed keyway on either side of the spindle is modified into an open through keyway, and the opening side of the open through keyway is connected to the end face of the spindle.

5. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 1, characterized in that, In steps (2.2) and (2.4): When measuring the actual clearance between the upper and lower inner rings of a rolling bearing, data should be measured at at least three points; and / or When rotating the outer ring of the rolling bearing, rotate at least three revolutions; and / or When rotating the outer ring of a rolling bearing, place a weight of not less than 10 kg at the fixed end of the upper inner ring of the rolling bearing.

6. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 1, characterized in that, In step (3.4), the rapid correction of the synchronization between the right and left eccentric gears includes: The round steel section of the helical gear precision calibration ruler is placed into the tooth groove of the right eccentric gear. The rectangular ruler of the helical gear precision calibration ruler is freely and vertically pointed to the bottom left eccentric gear. At this time, the offset of the outer and inner angles of the right and left eccentric gears is immediately measured, and the right eccentric gear is tapped to rotate slightly to achieve correction. Take three consecutive measurements, including at least the keyway near the shaft hole of the right eccentric gear and the pin near the connecting rod. The total time for the calibration process shall not exceed 5 minutes.

7. The assembly method of the driven shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to claim 1, characterized in that: In step (5.1), when the offsets of the inner and outer sides of the helical gear both meet the helical gear assembly standard of the driven shaft device, the synchronization of the left and right eccentric gears is qualified; otherwise, disassembly and rework are required; and / or In step (5.2), if the clearance between the outer rings of both rolling bearings and the rolling elements of the upper inner rings on their inner sides both meet the working clearance standard for the rolling bearings of the driven shaft device, then the working clearance of the rolling bearings is qualified; otherwise, they are disassembled and reworked; and / or In step (5.3), if the gap at the mating point of each component assembled on the main shaft of the passive shaft device is not zero, the gap is eliminated by axial pressing so that the gap at the mating point of each component is zero.

Images