Method for installing a driven shaft device of a main transmission mechanism of a seamless steel tube cold rolling mill

Abstract

The application discloses a seamless steel pipe cold rolling mill main transmission mechanism passive shaft device on-machine installation method, including the following steps: 1) operation preparation; 2) passive shaft device overall on-machine; 3) passive shaft device axial positioning determination: with the rolling center line as the reference, the axial positioning of the passive shaft device is carried out, and the width of the left and right adjustment distance rings is determined; 4) passive shaft device axial positioning installation: the left and right adjustment distance rings are matched and installed, and the axial positioning precision of the left and right adjustment distance rings is determined; 5) installation precision inspection; 6) mill stand cover fastening. The present application has the advantages of reasonable process design, compact process connection, high passive shaft device axial positioning precision, good stability, convenient operation, remarkable anti-deformation and anti-escape effect, and on the basis of ensuring the precision of passive shaft device on-machine installation, the technical requirements of high alloy element, high strength new steel seamless steel pipe cold rolling are met, the installation quality is controlled and stable, practical and efficient, safe and reliable.

Description

Technical Field

[0001] This invention relates to cold rolling production equipment for seamless steel pipes in the metallurgical and machinery industries. More specifically, it relates to a method for installing the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill on the machine, particularly a method to ensure the installation accuracy of the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill. This method is especially suitable for the precision installation of the passive shaft device with a crank-connecting rod structure on the main drive machine base platform. 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 periodic cold rolling mill mainly 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] Combination Figure 2 As shown, the main drive mechanism mainly consists of a base 3, a pulley system, a reduction gear, a drive shaft system 4, a driven shaft system 1, connecting rods 5 and 6, etc. Structurally, the base 3 is installed as a whole in a concrete foundation pit. Currently, the main drive mechanism can be divided into two types according to the installation position of its base: front-mounted and rear-mounted. In the front-mounted layout, the base 3 of the main drive mechanism is located in front of the rolling mechanism; in the rear-mounted layout, the base 3 is located behind the rolling mechanism. Both can meet the needs of seamless steel pipe transmission; the difference lies in the configuration based on the requirements of the equipment installation position. The pulley assembly is installed on one side of the machine base 3 and connected to the main motor via coupling 7. The reduction gear is installed between the pulley assembly and the machine base, and is connected to both the pulley assembly and the drive shaft assembly 4. The drive shaft assembly 4 is installed on the machine base 3 (on the outer side) and connected to the reduction gear via coupling 7. The driven shaft assembly is installed on the machine base (on the inner side, adjacent to the rolling mechanism) and is connected to the working frame 2 of the rolling mechanism via left and right connecting rods 5 and 6 on the left eccentric gear 11 and right eccentric gear 12 installed on both sides of the driven shaft assembly 4. Therefore, the driven shaft assembly 4 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 effectively through the driven shaft assembly 4.

[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 1 mainly consists of a left eccentric gear 11, a right eccentric gear (crank) 12, a rolling bearing 14 (double-row short cylindrical roller bearing), 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, etc. (see [reference]). Figure 1 (As shown). The accuracy of the passive shaft device 1 mainly consists of the assembly accuracy of each component of the passive shaft under offline working conditions and the installation accuracy of the entire passive shaft device on the main drive base platform. Both are indispensable.

[0007] Combination Figure 2 As shown, the installation of the passive shaft assembly involves mounting the passive shaft assembly 1, which has been assembled and inspected under offline conditions, onto the main drive base 3 platform of the cold rolling mill. The base platform adopts a split structure, consisting of a base and a top cover, and the passive shaft assembly 1 is fixed with bolts. The rolling bearings of the passive shaft assembly 1 are installed in the split circular holes of the base platform. Split bearing bushes 21 are installed between the rolling bearings 14 and the circular holes of the base platform to avoid wear damage to the circular holes of the base platform. The eccentric gears on both sides of the passive shaft assembly are placed in the cavities on both sides of the base platform. The left and right connecting rods 5 and 6 connect the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft to both sides of the working frame 2 (see...). Figure 2 (As shown).

[0008] Regarding the accuracy of the passive shaft assembly on the main drive platform, it mainly involves two aspects: the fitting accuracy of the rolling bearing and the split bearing bush, and the axial accuracy of the passive shaft assembly on the main drive platform.

[0009] in:

[0010] 1) The fitting accuracy between the rolling bearing and the split bearing bush is mainly caused by the wear and deformation of the bearing bush, which will directly affect the stability of the driven shaft device on the main drive platform. Usually, the split bearing bush needs to be replaced regularly or periodically to ensure the installation accuracy and stability between the rolling bearing and the main drive platform.

[0011] 2) The axial accuracy of the passive shaft assembly on the main drive base platform refers to the axial displacement and deviation error of the entire passive shaft assembly on the main drive base platform. This error is caused by inaccurate axial positioning during installation, which will cause the passive shaft to deviate to one side after installation and drive the drive shaft assembly to deviate synchronously during subsequent rotational motion. This is a difficult point in the installation of the passive shaft assembly. Currently, the axial positioning of the passive shaft assembly during installation relies on the retaining ring installed on the main shaft of the passive shaft assembly between the rolling bearing and the eccentric gear. The outer shaft diameter is initially positioned by the annular grooves on both sides of the circular hole in the base platform. Then, the precision positioning is achieved by the adjusting spacer rings on the inner side of the two sets of rolling bearings and the shaft shoulder of the circular hole in the base platform.

[0012] In production practice, the installation process of the driven shaft assembly includes: receiving (or preparing) the driven shaft assembly (installed as a component offline) → cleaning the main drive platform → cleaning the driven shaft assembly → suspending the driven shaft assembly above the main drive platform using lifting machinery → installing the entire driven shaft assembly into the split stepped hole on the main drive platform → during installation, inserting the inner retaining ring of the eccentric gear of the driven shaft assembly into the annular grooves on both sides of the split stepped hole on the main drive platform → preliminary axial positioning → measuring the distance between the end face (shoulder) of the split hole on the main drive platform and the inner side of the outer ring of the rolling bearing → fitting the adjusting spacer ring → installing the adjusting spacer ring → cleaning the contact surface → installing the platform cover using lifting machinery → tightening the bolts → inspecting the gear meshing accuracy, etc. While the above method can complete the installation of the driven shaft assembly, it has certain shortcomings:

[0013] 1) Uncontrolled Axial Positioning Accuracy, Prone to Errors: Currently, the axial positioning of the passive shaft device is achieved by two retaining rings on both sides and two sets of adjusting spacer rings. The retaining rings are relatively fixed and their shape and size (thickness) remain unchanged. Their function is to prevent the outer ring of the rolling bearing from shifting outward, thus axially fixing the passive shaft device. The adjusting spacer rings are located between the outer rings of the two sets of rolling bearings and the shoulder of the stepped hole in the machine base platform, preventing the rolling bearings from shifting inward. Therefore, the width of the adjusting spacer rings is the key point for axial positioning. Structurally, the rolling bearings are clamped by the outer retaining rings and the inner adjusting spacer rings, realizing the axial positioning function of the passive shaft device in the split hole of the machine base platform. Due to machining errors of the gears and spindle of the passive shaft device, the centerline of the passive shaft will deviate from the rolling centerline on the machine base platform during installation. At the same time, since the driving shaft and the passive shaft device of the main drive mechanism use helical gears, there will definitely be periodic reciprocating axial displacement during meshing. Therefore, the existing positioning method cannot accurately determine the width of the adjusting spacer rings, resulting in deviations in the installation accuracy.

[0014] 2) Inappropriate Installation Method: Theoretically, the installation of both the drive shaft and driven shaft of the main drive mechanism should be based on the rolling center line of the cold rolling mill. The driven shaft is primarily positioned, and the drive shaft is adjusted according to the positioning of the driven shaft (the drive shaft has a slight axial movement function). However, the rolling center line is a virtual straight line. In the past, a rolling center line (steel wire) was set during equipment installation and removed after the equipment was safely commissioned. Therefore, during routine equipment maintenance and replacement of the drive shaft and driven shaft of the main drive mechanism, due to limitations, it was not possible to set the rolling center line. Instead, the two end faces of the machine base platform were used as a reference, and axial installation positioning was achieved by correcting the distance between the inner plane of the eccentric gear of the driven shaft and the two end faces of the machine base platform. This method suffers from inconsistencies between the design reference, installation reference, and usage reference, resulting in uncontrolled installation accuracy.

[0015] 3) The adjusting distance ring is prone to deformation and escape: The existing adjusting distance ring is a split ring structure. One side of the split is a straight line and the other side is a bevel (bevel). The purpose of machining the bevel is to facilitate the guidance and installation. However, since the function of the adjusting distance ring is axial positioning, it bounces under the action of axial force when the driven shaft device is running at high speed. It is prone to deformation and escape, which directly affects the accurate axial positioning of the driven shaft device. It is a failure point in the daily operation of the driven shaft device. The deformation and escape phenomenon is particularly obvious when the axial positioning gap is too large.

[0016] In summary, the current method for installing 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, with the development and production of high-alloy, high-strength seamless steel pipes, which are in high demand in the market, the load during cold rolling is significantly increased. This leads to a corresponding increase in the load on the main drive mechanism, including the passive shaft device, resulting in a significantly higher failure rate and maintenance costs for the passive shaft device. Major failure points include accelerated wear of the passive shaft gears, failure of rolling bearings, and accelerated wear and deformation of the bearing shells. The root cause is closely related to the accuracy of the overall installation of the passive shaft device, particularly the error between the axial installation position and the rolling centerline. Therefore, only through corresponding technical improvements, optimized work processes, and improved installation accuracy of the passive shaft device can the requirements for seamless steel pipe cold rolling be met, equipment maintenance costs and downtime reduced, and the company's core market competitiveness further enhanced. Summary of the Invention

[0017] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a method for installing the passive shaft device of the main drive mechanism in a seamless steel pipe cold rolling mill. This method features a reasonable process design, a compact workflow, high axial positioning accuracy and stability of the passive shaft device, convenient operation, and significant anti-deformation and anti-escape effects. While ensuring the accuracy of the passive shaft device installation, it meets the technical requirements for cold rolling of high-alloy, high-strength seamless steel pipes. The installation quality is controlled and stable, making it practical, efficient, safe, and reliable.

[0018] To achieve the above objectives, the present invention adopts the following technical solution:

[0019] A method for installing the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill includes the following steps:

[0020] 1) Homework preparation;

[0021] 2) Installation of the passive shaft assembly: The passive shaft assembly is suspended above the base of the main drive mechanism for preliminary pre-installation and positioning;

[0022] 3) Axial positioning measurement of the passive shaft device: The axial positioning of the passive shaft device is performed with the rolling centerline as the reference, and the widths of the left and right adjustment distance rings are determined.

[0023] 4) Axial positioning installation of the passive shaft device: Make and install the left and right adjusting distance rings, and measure the axial positioning accuracy of the left and right adjusting distance rings;

[0024] 5) Installation accuracy inspection;

[0025] 6) Secure the base cover tightly.

[0026] Preferably, in step 1), the work preparation includes safety technical briefing, implementation of on-site safety precautions, preparation of tools and materials, cleaning of spare parts and materials and verification of drawings, and modification and adjustment of the fixed distance ring.

[0027] Preferably, in step 1), the cut on one side of the adjusting distance ring is an acute-angle tongue and groove, and the adjusting distance ring is pre-machined with a machining allowance.

[0028] Preferably, the machining allowance is 2-3 mm.

[0029] Preferably, in step 2), the overall installation of the passive shaft device further includes:

[0030] 2.1) Preparation for computer use;

[0031] 2.2) Install the bearing bushes, and install the split bearing bushes in the stepped holes of the machine base platform and the stepped holes of the upper cover;

[0032] 2.3) Suspend the entire passive shaft assembly and lift and transport it to the top of the main drive mechanism's base platform;

[0033] 2.4) Initial pre-assembly on the machine: Adjust the position of the stepped hole of the base platform of the driven shaft device and the main drive mechanism so that the retaining rings on the inner side of the left and right eccentric gears of the driven shaft device are embedded in the annular grooves on both sides of the countersunk hole of the base platform, and the outer circumferential surface of the rolling bearing is in contact with the inner circumferential surface of the bearing bush.

[0034] 2.5) Initial positioning of the passive shaft device: Rotate the passive shaft device at least one revolution based on the countersunk hole of the machine base platform to perform initial axial positioning, and ensure that the left and right eccentric gears of the passive shaft device are at the bottom due to gravity.

[0035] Preferably, in step 3), the axial positioning determination of the passive shaft device further includes:

[0036] 3.1) Determine the rolling centerline by using a laser rangefinder to generate a laser beam from the original reference of the seamless steel pipe cold rolling mill to calibrate the rolling centerline;

[0037] 3.2) Axial position determination: Based on the rolling center line marked by the laser beam, measure the actual distance values ​​L1 and L2 between the inner end faces of the left and right eccentric gears of the passive shaft device and the rolling center line, as well as the distance L between the inner sides of the left and right eccentric gears of the passive shaft device, and determine the offset direction and offset amount of the passive shaft device.

[0038] 3.3) Axial position correction: Axial correction is performed based on the measured values ​​of L1 and L2 to ensure that the distance between the inner surfaces of the left and right eccentric gears of the driven shaft device is L = L1 + L2, and L1 ≈ L2, and the error value does not exceed 1.0 mm.

[0039] 3.4) Determine the width value of the adjustment spacer ring, perform axial measurement on the passive shaft device after axial correction, and obtain the distance values ​​b1 and b2 between the inner sides of the left and right eccentric gears of the passive shaft device and the two sides of the machine base platform. Calculate the distance values ​​a1 and a2 between the left and right rolling bearings and the shoulder of the stepped hole of the machine base platform, using the rolling center line as the reference. Where a1 = (L-L3) / 2 - b1 - cd, a2 = (L-L3) / 2 - b2 - cd, L3 is the width value of the shoulder of the stepped hole between the split bearing bushes of the passive shaft device installed on the machine base platform of the main transmission mechanism, c is the width value of the retaining ring, and d is the width value of the outer ring of the rolling bearing. a1 and a2 are the width values ​​of the adjustment spacer ring for the left and right eccentric gears.

[0040] Preferably, in step 3.2), the correction is performed according to the offset direction and offset amount. When L1 > L2, it indicates that the passive shaft device is offset to the left, and the offset amount is L1 - 1 / 2L; when L1 < L2, it indicates that the passive shaft device is offset to the right, and the offset amount is L2 - 1 / 2L.

[0041] Preferably, in step 3.3), when the passive shaft device is suspended, the gap between the rolling bearing and the bearing bush is 2 to 5 mm.

[0042] Preferably, in step 4), the axial positioning and installation of the passive shaft device further includes:

[0043] 4.1) Make left and right adjustment positioning rings, and perform precision grinding on a grinding machine according to a1 and a2 obtained in step 3) to ensure that the error value of the width of the machined adjustment positioning ring is ≤0.05mm;

[0044] 4.2) Install the axial positioning elements. Install the precision-machined adjusting positioning rings between the corresponding machine base platform stepped hole shoulder and the rolling bearing, and ensure that they are installed in place.

[0045] 4.3) Adjust the axial positioning accuracy of the positioning ring. Use a feeler gauge of 0.02 to 0.05 mm to measure and adjust the clearance between the two sides of the positioning ring and the rolling bearing and the shoulder of the step hole of the machine base platform, and ensure that the clearance value is not greater than 0.05 mm.

[0046] Preferably, in step 5), the installation accuracy inspection further includes:

[0047] 5.1) Axial positioning accuracy inspection: The distance between the inner side of the left and right eccentric gears and the rolling center line is measured using a laser rangefinder. The distance error is ≤1.0mm.

[0048] 5.2) Radial installation accuracy inspection: Use a feeler gauge of 0.02 to 0.05 mm to inspect the contact surface fit between the rolling bearing and the bushing, and between the bushing and the countersunk hole of the machine base platform step, to ensure that the gap value is ≤0.05 mm.

[0049] Preferably, in step 6), the fastening of the base cover further includes cleaning the working surface, cleaning the contact surface with the base platform and the driven shaft device, suspending and fastening the base platform cover, and cleaning the work site.

[0050] The present invention provides a method for installing the passive shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill, which has the following advantages:

[0051] 1) This invention improves the operation and maintenance of the main drive mechanism of the existing two-roll periodic seamless steel pipe cold rolling mill. It consists of four main processes: overall installation of the passive shaft device, axial positioning measurement, axial positioning installation, and machine base cover fastening, as well as two auxiliary processes: operation preparation and installation accuracy inspection. The process design is reasonable, the process connection is compact, the axial positioning accuracy of the passive shaft device is high, the stability is good, the operation is convenient, and the anti-deformation escape effect is significant.

[0052] 2) This invention uses the rolling centerline as a reference and determines the width of the adjusting ring by an online measurement and calculation model, which improves the accuracy of axial positioning. The axial positioning error is ≤1.0mm, ensuring that the overall installation accuracy of the passive shaft device meets the technical requirements of cold-rolled tubes.

[0053] 3) This invention, while ensuring the accuracy of the passive shaft device installation on the machine, meets the technical requirements of cold-rolled seamless steel pipes made of high-alloy elements and high-strength new steel grades. The installation quality is controlled and stable, practical, efficient, safe and reliable.

[0054] 4) The present invention optimizes and adjusts the structure of the spacer ring, and adopts a tongue and groove shape to improve the stability under axial load while satisfying the installation guidance function, and effectively prevents deformation from escaping.

[0055] 5) The measurement and calculation model used in this invention is reasonably designed, easy to operate, does not require high experience and skills from operators, facilitates standardized operation, and is practical and efficient;

[0056] 6) This invention effectively improves the operating accuracy and stability of the main drive mechanism, significantly reduces the failure of the driven shaft device, effectively guarantees the service life and operating quality, reduces equipment downtime and maintenance resource consumption, and has a certain effect of eliminating failures, reducing costs and promoting production;

[0057] 7) Applicable to the technical requirements of passive shaft device installation on multi-model two-roll periodic cold rolling tube mill, with high installation accuracy, meeting the cold rolling tube production needs of seamless steel pipes of various steel grades and specifications, and is replicable and applicable, promoting the core competitiveness of enterprises in the market;

[0058] 8) This invention is highly versatile and has certain reference and application value for the technical improvement of the main drive mechanism of the two-roll periodic seamless steel pipe cold rolling mill. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill;

[0060] Figure 2 This is a schematic diagram of the installation of the main drive mechanism on the seamless steel pipe cold rolling mill.

[0061] Figure 3 This is a schematic diagram of the installation of the passive shaft device of the main drive mechanism on the seamless steel pipe cold rolling mill.

[0062] Figure 4 This is a schematic diagram of the installation parameters of the passive shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill of the present invention.

[0063] Figure 5 This is a schematic diagram of the existing adjustable spacing ring structure;

[0064] Figure 6 This is a schematic diagram of the adjusting distance ring of the present invention;

[0065] Figure 7 This is a process flow diagram of the installation method of the passive shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to the present invention;

[0066] In the diagram, 1 is the driven shaft assembly; 2 is the machine frame; 3 is the machine base; 4 is the drive shaft assembly; 5 is the left connecting rod; 6 is the right connecting rod; 7 is the coupling; 11 is the left eccentric gear; 12 is the right eccentric gear; 13 is the main shaft; 14 is the rolling bearing; 15 is the retaining ring; 16 is the positioning sleeve; 17 is the support ring; 18 is the flat key; 19 is the connecting rod pin; 20 is the adjusting distance ring; 21 is the bearing shell; K is the rolling center line; M is the driven shaft center line. Detailed Implementation

[0067] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0068] A steel pipe plant of a steel company in Shanghai uses a method provided by this invention to ensure the installation accuracy of 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 the two-roll periodic seamless steel pipe cold rolling mill. It consists of four main processes: overall installation of the passive shaft device, axial positioning measurement, axial positioning installation, and machine base cover tightening; and two auxiliary processes: operation preparation and installation accuracy inspection. Specifically: operation preparation → overall installation of the passive shaft device → axial positioning measurement → axial positioning installation → installation accuracy inspection → machine base cover tightening. The method uses the rolling center line K as a reference to ensure that the overall installation accuracy of the passive shaft device meets the technical requirements for cold-rolled pipe production.

[0069] Please combine Figure 7 As shown, the present invention provides a method for installing the driven shaft device of the main drive mechanism of a seamless steel pipe cold rolling mill, which includes the following steps:

[0070] 1) Work preparation: Safety technical briefing, implementation of on-site safety precautions, preparation of tools and materials, cleaning of spare parts and materials and verification of drawings, modification and adjustment of the fixed distance ring.

[0071] Safety briefing and identification of hazards before work, implementation and inspection of on-site safety precautions, preparation of tools, equipment and materials, etc.

[0072] 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.

[0073] Preparation of the adjusting distance ring: Prepare and process the adjusting distance ring 20 according to the improved requirements, with one side of the cut being a bevel (see...). Figure 5 (As shown) Change to an acute-angle tongue and groove (see) Figure 6 As shown in the drawing, new products can be processed and prepared according to the revised drawing requirements. It should be noted that the thickness of the adjusting ring 20 should be reserved with a machining allowance of 2 to 3 mm.

[0074] 2) The entire passive shaft assembly is installed on the machine (passive shaft assembly 1 has been installed according to the instructions). Figure 1 (As shown in the diagram, complete the assembly), combined Figure 3 As shown, the specific steps include:

[0075] 2.1) Machine preparation: Clean all contact parts of the main drive base 3 platform (focusing on the inner circumferential surface of the split stepped hole and annular groove, shaft shoulder, etc., to ensure there are no impurities, oil stains, etc.); clean the installation part of the driven shaft device 1 (focusing on the outer circumferential surface of the rolling bearing 14, positioning sleeve 16, retaining ring 15, shaft shoulder side, etc., to ensure there are no impurities, oil stains, etc.).

[0076] 2.2) Install the bearing bushes, and install the split bearing bushes 21 in the stepped holes of the machine base 3 platform and the stepped holes of the upper cover;

[0077] Combination Figure 3 As shown, the new split bearing 21 is installed in the platform step hole and the upper cover step hole of the main drive machine base 3, and is positioned by set screws. It should be noted that the bearing 21 does not need to be replaced every time the passive shaft device 1 is replaced. Instead, it should be determined according to the actual wear and deformation of the bearing. Therefore, this step is determined according to the work process.

[0078] 2.3) Suspend the entire passive shaft device 1 and lift and transport it to the platform directly above the main drive base 3 of the cold rolling mill;

[0079] Using lifting machinery (preferably a bridge crane), a steel wire rope is passed through the unified orientation process holes of the left eccentric gear 11 and right eccentric gear 12 of the entire passive shaft device 1 to lift and transport the entire passive shaft device 1 to the platform directly above the base 3 of the main drive mechanism of the cold rolling mill.

[0080] 2.4) Initial pre-assembly on the machine: Adjust the position of the driven shaft assembly 1 and the stepped hole of the main drive base 3 platform so that the retaining rings 15 on the inner sides of the left eccentric gear 11 and right eccentric gear 12 of the driven shaft assembly 1 are embedded in the annular grooves on both sides of the countersunk hole of the main drive base 3 platform, and the outer circumferential surface of the rolling bearing 14 is in contact with the inner circumferential surface of the bearing bush 21 (see...). Figure 3 (as shown);

[0081] The crane hook descends at a constant speed. The operator directs the crane's movements while manually adjusting the position of the driven shaft device and the stepped hole (bearing bush) of the main drive base 3 platform. It is necessary to ensure that the retaining rings 15 on the inner sides of the left eccentric gear 11 and right eccentric gear 12 of the driven shaft device are embedded in the annular grooves on both sides of the countersunk hole of the main drive base 3 platform, and that the outer circumferential surface of the rolling bearing 14 is in contact with the inner circumferential surface of the bearing bush.

[0082] 2.5) Initial positioning of the passive shaft device: Rotate the passive shaft device 1 at least one revolution based on the countersunk hole of the machine base platform to perform initial axial positioning, and ensure that the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device are at the bottom due to gravity.

[0083] Using a lifting mechanism (or manual rotation for small cold rolling mills), the passive shaft device 1 is rotated at least one revolution based on the countersunk hole of the machine base 3 platform to initially position it axially, and to ensure that the eccentric parts of the left eccentric gear 11 and the right eccentric gear 12 are at the bottom due to gravity.

[0084] 3) Axial positioning measurement of the passive shaft device: Axial positioning is performed using the rolling centerline as a reference, and the width values ​​of the left and right adjusting distance rings are determined; combined with... Figure 4 As shown, the specific steps include:

[0085] 3.1) Determine the rolling center line K. Use a laser rangefinder to generate a laser beam from the original reference of the seamless steel pipe cold rolling mill to calibrate the rolling center line K as the installation reference.

[0086] 3.2) Axial position determination: Based on the rolling center line K marked by the laser beam, measure the actual distances L1 and L2 between the inner end faces of the left and right eccentric gears of the passive shaft device 1 and the rolling center line K, as well as the distance L between the inner surfaces of the left and right eccentric gears 11 and 12 of the passive shaft device. Determine the offset direction and amount of the passive shaft device. When L1 > L2, it indicates that the passive shaft device is offset to the left, with an offset of L1 - 1 / 2L. When L1 < L2, it indicates that the passive shaft device is offset to the right, with an offset of L2 - 1 / 2L. When correcting after axial position determination, the standard is "L = L1 + L2, and L1 = L2. It should be noted that in reality, L1 cannot be exactly equal to L2, but the difference between L1 and L2 should preferably be ≤1.0mm".

[0087] 3.3) Axial Position Correction: Axial correction is performed based on the measured values ​​of L1 and L2. The driven shaft device is pried to correct the axial alignment, ensuring that the inner sides of the left eccentric gear 11 and right eccentric gear 12 of the driven shaft device 1 are slightly suspended using a lifting machine (with the clearance between the rolling bearing 14 and the bearing bush being 2-5mm). The driven shaft device is then manually pried, and the correction is performed according to the offset direction and offset amount in step 3.2). Specifically, when L1 > L2, it indicates that the driven shaft device has shifted to the left, with an offset amount of L1 - 1 / 2L, requiring correction towards the right eccentric wheel; when L1 < L2, it indicates that the driven shaft device has shifted to the right, with an offset amount of L2 - 1 / 2L, requiring correction towards the left eccentric wheel. Afterwards, the driven shaft device 1 is measured again after axial correction to ensure that L = L1 + L2, and L... 11 ≈L2, with an error value not exceeding 1.0mm, the purpose of which is to ensure that the error of the center line meets the technical requirements.

[0088] 3.4) Determine the width value of the adjusting spacer ring 20, perform axial measurement on the passive shaft device 1 after axial correction, and obtain the distance values ​​b1 and b2 between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device 1 and the two sides of the machine base 3 platform. Calculate the distance values ​​a1 and a2 between the rolling bearings 14 on the left and right sides and the stepped hole shoulders of the machine base 3 platform, using the rolling center line K as the reference. Where a1 = (L-L3) / 2 - b1 - cd, a2 = (L-L3) / 2 - b2 - cd, L3 is the width value of the stepped hole shoulders between the split bearing bushes 21 of the passive shaft device 1 installed on the machine base 3 platform of the main transmission mechanism, c is the width value of the retaining ring 15, and d is the width value of the outer ring of the rolling bearing 14. a1 and a2 are the width values ​​of the adjusting spacer ring for the left eccentric gear and the adjusting spacer ring for the right eccentric gear.

[0089] Axial measurements were performed on the recalibrated and repositioned passive shaft assembly 1 using vernier calipers and gauge blocks. The main measurements included the distances b1 and b2 between the inner surfaces of the left and right eccentric gears 11 and 12 and the two sides of the machine base 3 platform. The distances a1 and a2 between the rolling bearings 14 on both sides and the stepped hole shoulders of the machine base 3 platform were calculated using the rolling center line K as a reference. The distance a1 between the left rolling bearing and the stepped hole shoulders of the machine base 3 platform is a1 = (L-L3) / 2 - b1 - cd, and the distance a2 between the right rolling bearing and the stepped hole shoulders of the machine base 3 platform is a2 = (L-L3) / 2 - b2 - cd. It should be noted that a1 and a2 can be measured on-site, but if the measured values ​​differ from the calculated values, the calculated values ​​should prevail. c and d are the widths of the bearing bush and retaining ring 15, respectively, and are fixed values; machining errors are negligible.

[0090] 4) Axial positioning installation of the passive shaft device: Make and install the left and right adjusting distance rings, and measure the axial positioning accuracy of the left and right adjusting distance rings to ensure axial positioning accuracy;

[0091] Combination Figure 4 , 6 As shown, the axial positioning and installation of the passive shaft device specifically includes the following steps:

[0092] 4.1) Make left and right adjustment positioning rings. Based on a1 and a2 calculated in step 3), perform precision grinding to ensure that the width of the machined adjustment positioning ring 20 meets the calculated values ​​of a1 and a2, and the error value is ≤0.05mm.

[0093] 4.2) Install the axial positioning elements, and install the precision-machined adjusting distance rings 20 between the corresponding machine base 3 platform stepped hole shoulder and rolling bearing 14, and ensure that they are installed in place;

[0094] Two adjusted spacer rings, the left and right adjusted spacer rings, which have undergone matching grinding, are installed between the corresponding machine base 3 platform stepped hole shoulder and rolling bearing 14. During installation, it is necessary to ensure that the tongue and groove of the adjusted spacer ring 20 are flush and properly engaged. It should be noted that when installing the adjusted spacer ring 20, the installation positions of the adjusted spacer rings 20 with width values ​​a1 and a2 must not be incorrect. The adjusted spacer ring 20 with width value a1 should be installed between the left rolling bearing 14 and the machine base 3 platform stepped hole shoulder, and the adjusted spacer ring 20 with width value a2 should be installed between the right rolling bearing 14 and the machine base 3 platform stepped hole shoulder.

[0095] 4.3) Adjust the axial positioning accuracy of the positioning ring 20. Use a feeler gauge of 0.02 to 0.05 mm to measure and adjust the gap between the two sides of the positioning ring 20 and the rolling bearing 14 and the shoulder of the stepped hole of the platform of the machine base 3, and ensure that the gap value is not greater than 0.05 mm.

[0096] Use a 0.02-0.05mm feeler gauge to measure the clearance between the two sides of the spacer ring 20 and the rolling bearing 14 and the shoulder of the stepped hole of the platform of the machine base 3. The clearance values ​​at both locations should not exceed 0.05mm. If they exceed 0.05mm, it indicates that there is an error in the calculation accuracy, and it is necessary to re-measure, recalculate, process, and reinstall.

[0097] 5) Installation accuracy inspection, combined with Figure 4 As shown, the specific steps include:

[0098] 5.1) Axial positioning accuracy inspection: The distance between the inner side of the left eccentric gear 11 and the right eccentric gear 12 and the rolling center line K is measured using a laser rangefinder. The distance error is ≤1.0mm.

[0099] 5.2) Radial (circumferential) installation accuracy inspection: Use a feeler gauge of 0.02 to 0.05 mm to inspect the contact surface fit between the rolling bearing 14 and the bushing 21, and between the bushing 21 and the platform stepped hole of the machine base 3, to ensure that the clearance value is ≤0.05 mm.

[0100] 6) Secure the base cover, which includes cleaning the work surface, cleaning the contact surface with the base platform and the driven shaft device, suspending and securing the base platform cover, and cleaning the work site.

[0101] Clean the working surfaces: Clean the contact surfaces of the machine base platform, the outer surface of the upper half of the rolling bearing 14, and other parts to ensure that there are no impurities, oil stains, etc.

[0102] Use lifting machinery to suspend the platform cover of the machine base and clean the contact surfaces (focusing on the countersunk holes, the inner circumference of the bearing bush, and the sides at both ends to ensure there are no impurities or oil stains).

[0103] Installation and fastening: Suspend the top cover directly above the main drive mechanism base platform, lower the hook at a uniform speed, and have the operator manually guide and straighten the top cover until it is accurately installed on the passive shaft device and base platform. After aligning the position, tighten the bolts and install the positioning pins.

[0104] Clean up the work site: Clean up the tools and equipment (measuring instruments) used in the work site to create workstation conditions for subsequent operations.

[0105] Following the above-described procedures, the on-site application of the passive shaft device installation method for the main drive mechanism of a seamless steel pipe cold rolling mill provided by this invention is completed. The installation accuracy error is controlled within ≤1.0mm. After completing subsequent related work, it is put into cold-rolled pipe production to meet the technical requirements for the production of high-strength, deformation-resistant nickel-based alloys, high-temperature alloys, duplex stainless steel, and other high-alloy steel products. Before being put into use, it is necessary to check the gear meshing between the drive shaft device 4 and the passive shaft device. The meshing state of the helical gears is inspected using methods such as lead pressing and coloring. A meshing area of ​​not less than 30% is considered qualified. After passing the inspection, subsequent items such as installing the protective cover, replenishing gear lubricant, and installing the lubrication pipeline of the rolling bearing 14 are completed before power-on debugging. It should be noted that after rolling three seamless steel pipes or 30 meters of finished products, the main drive machine base 3 platform cover needs to be retightened to eliminate the potential risks of ineffective tightening and loosening in the initial state. The passive shaft assembly is installed in the main drive base 3 and fixed by bolts. It requires regular maintenance (tightening, lubrication, etc.) and ensuring that the eccentric gear and rolling bearing 14 are continuously lubricated online during production to guarantee the service life of the passive shaft assembly.

[0106] It should be noted that the installation of the passive shaft device requires high precision and is time-consuming. It is typically performed in two ways: either the main drive mechanism's driving shaft device and the passive shaft device are replaced together, or only the passive shaft device is replaced. Based on the structural characteristics and motion requirements of the main drive mechanism, regardless of the method, the passive shaft device must be installed first for positioning and calibration of the driving shaft device's precision. However, in production practice, due to the larger size and greater installation difficulty of the passive shaft device compared to the driving shaft device, the driving shaft device is usually installed first, followed by the passive shaft device. Therefore, when initially adjusting the axial positioning of the passive shaft device, the impact of whether the driving shaft device has already been installed should be considered. It is also necessary to consider whether the left and right connecting rods 6 of the passive shaft device are installed on the passive shaft device before installation or installed online after the passive shaft device is installed. This also has a certain impact on the passive shaft device installation process, and engineering technicians should consider all aspects.

[0107] The following describes the installation method of the passive shaft device of the main drive mechanism of the seamless steel pipe cold rolling mill according to the present invention in conjunction with specific embodiments;

[0108] Example 1

[0109] This embodiment takes the LG-150H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ110~150mm as an example. Due to planned maintenance, the passive shaft device was completely replaced. The passive shaft device assembly had been completed in advance under offline conditions and is now being installed on the machine. The operation process includes: operation preparation → installation of the passive shaft device → axial positioning measurement → axial positioning installation → installation accuracy inspection → tightening of the machine base 3 cover. The installation accuracy of the passive shaft device is ensured to meet the technical requirements of cold-rolled pipe by using the rolling center line K as a reference.

[0110] 1) Work preparation procedures:

[0111] 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.

[0112] 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.

[0113] 1.3) Preparation of Adjustment Spacing Ring 20: The adjustment spacing ring 20 is prepared and processed according to the improved requirements, and the side cut is changed from a bevel to an acute-angle tongue and groove (see...). Figure 6 As shown), new products can be processed and prepared according to the revised drawings. It should be noted that the thickness of the adjusting ring 20 should be reserved with a machining allowance of 2 to 3 mm, that is, the width of the adjusting ring 20 = 25 + 3 = 28 mm.

[0114] 2) The entire passive shaft assembly is installed on the machine (see...) Figure 2 , Figure 3 )

[0115] 2.1) Machine preparation: Clean all contact parts of the base 3 platform of the main drive mechanism (focusing on the inner circumferential surface of the split stepped hole and the annular groove, the shaft shoulder, etc., to ensure that there are no impurities, oil stains, etc.); clean the driven shaft mounting part (focusing on the outer circumferential surface of the rolling bearing 14, the positioning sleeve 16, the retaining ring 15, the side of the shaft shoulder, etc., to ensure that there are no impurities, oil stains, etc.).

[0116] 2.2) Installing the bearing shell 21: Since it was found that the bearing shell 21 on the countersunk hole of the machine base 3 platform was deformed and worn due to the damage of the rolling bearing 14 of the driven shaft device after opening the main drive mechanism, it is necessary to replace it with a new bearing shell 21; install the new split bearing shell 21 in the stepped hole of the machine base 3 platform and the stepped hole of the upper cover respectively, and use set screws for positioning.

[0117] 2.3) Suspended on the machine: Using lifting machinery (preferably a bridge crane), the entire passive shaft device is lifted and transported to the platform directly above the base 3 of the main drive mechanism of the cold rolling mill by passing a steel wire rope through the process hole of the left eccentric gear 11 and the right eccentric gear 12.

[0118] 2.4) Preliminary pre-assembly on the machine: The hook of the lifting machinery descends at a uniform speed. On the one hand, the operator directs the operation of the lifting machinery, and on the other hand, manually adjusts the position of the passive shaft device and the stepped hole (bearing shell 21) of the main drive base 3 platform. It is necessary to ensure that the retaining ring 15 on the inner side of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device is embedded in the annular groove on both sides of the countersunk hole of the base 3 platform, and the outer circumferential surface of the rolling bearing 14 is in contact with the inner circumferential surface of the bearing shell 21.

[0119] 2.5) Preliminary positioning of the passive shaft device: Use a crane to pull the device (or manually rotate it for small cold rolling mills) so that the passive shaft device rotates at least one revolution based on the countersunk hole of the machine base 3 platform to initially position it axially, and ensure that the eccentric parts of the left eccentric gear 11 and the right eccentric gear 12 are at the bottom due to gravity.

[0120] 3) Axial positioning measurement of the driven shaft assembly (see...) Figure 4 (As shown)

[0121] 3.1) Determine the rolling center line K: Use a laser rangefinder to generate a laser beam from the original reference of the seamless steel pipe cold rolling mill to calibrate the rolling center line K as the installation reference.

[0122] 3.2) Axial position determination: Based on the rolling center line K marked by the laser beam, measure the actual distances L1 and L2 between the inner end faces of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device and the rolling center line K, as well as the distance L between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device, and determine the offset direction and offset amount of the passive shaft device. Among them, the measured parameters are L = 860mm, L1 = 435mm, and L2 = 425mm. At this time, L1 > L2 indicates that the passive shaft device is offset to the left, and the offset amount = L1 - 1 / 2L = 435 - 860 / 2 = 5mm.

[0123] 3.3) Axial position correction: Correction is performed based on the measured values ​​of L1 = 433mm and L2 = 427mm. A lifting machine is used to slightly suspend the shaft (preferably with a gap of 2-5mm between the rolling bearing 14 and the bushing 21). The correction is performed according to the offset direction and amount determined in step 3.2). Following the direction of the rightward eccentric gear, the driven shaft device is manually pried to correct the axial position, ensuring L = L1 + L2, L1 ≈ L2, and an error value ≤ 1.0mm. After correction, the lifting machine hook is lowered, and the rolling bearing 14 and bushing 21 return to contact. L1 = 429.2mm and L2 = 430.8mm are measured again. At this point, L1 < L2, indicating that the driven shaft device has shifted to the right. The offset amount = L2 - 1 / 2L = 430.8 - 860 / 2 = 0.80mm, which meets the requirement of an error value ≤ 1.0mm.

[0124] 3.4) Determine the width value of the adjusting distance ring 20: Use vernier calipers and gauge blocks to measure the axial direction of the passive shaft device after recalibration and positioning. The main measurements are the distance values ​​b1 and b2 between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 and the two sides of the machine base 3 platform. The distance values ​​a1 and a2 between the left rolling bearing, the right rolling bearing and the shoulder of the stepped hole of the machine base 3 platform are calculated with the rolling center line K as the reference. a1=(L-L3) / 2-b1-cd, a2=(L-L3) / 2-b2-cd. On-site measurements showed b1 = 59.2mm, b2 = 60.8mm, L3 = 160mm, the width c of retaining ring 15 was 40mm, and the width b of the outer ring of rolling bearing 14 was 225mm. Calculations showed a1 = (L-L3) / 2 - b1 - cd = (860-160) / 2 - 59.2 - 40 - 225 = 25.8mm, and a2 = (L-L3) / 2 - b2 - cd = (860-160) / 2 - 60.8 - 40 - 225 = 24.2mm. Simultaneously, on-site measurements showed a1 = 25.6mm and a2 = 24.3mm. In cases where the measured values ​​differ from the calculated values, the calculated values ​​shall prevail.

[0125] 4) Axial positioning and installation of the driven shaft assembly (see...) Figure 3 )

[0126] 4.1) Matching the left and right adjustment distance rings: According to the a1 and a2 parameter values ​​obtained from the calculation model, perform precision grinding. The thickness value of the adjustment distance ring 20 must meet the calculated values ​​of a1 and a2, and the error value ≤ 0.05mm. Therefore, the width value of the distance ring is matched with a1 = 25.8 ± 0.02mm and a2 = 24.2 ± 0.02mm.

[0127] 4.2) Install axial positioning elements: Install two adjusting spacer rings with widths of a1 = 25.8 ± 0.02 mm and a2 = 24.2 ± 0.02 mm, respectively, in the left-right direction between the shoulder of the stepped hole of the machine base 3 platform and the rolling bearing 14. During installation, ensure that the tongue and groove of the adjusting spacer ring 20 are flush and properly engaged.

[0128] 4.3) Adjusting the axial positioning accuracy of the spacer ring 20: Use a 0.02-0.05mm feeler gauge to measure the clearance between the two sides of the spacer ring 20 and the rolling bearing 14 and the shoulder of the stepped hole of the platform of the machine base 3. The clearance values ​​at both locations should not exceed 0.05mm. If they exceed 0.05mm, it indicates that there is an error in the calculation accuracy, and it is necessary to re-measure, recalculate, process, and reinstall.

[0129] 5) Installation accuracy inspection

[0130] 5.1) Axial positioning accuracy inspection: The distance between the inner side of the left eccentric gear 11 and the right eccentric gear 12 and the rolling center line K was measured using a laser rangefinder. The distance error should be ≤1.0mm. The actual measurement showed that L1 = 429.3mm and L2 = 430.7mm. The entire passive shaft device was offset to the right eccentric gear direction by 0.70mm, which meets the error accuracy technical requirements.

[0131] 5.2) Radial (circumferential) installation accuracy inspection: Use a 0.02-0.05mm feeler gauge to inspect the contact surface fit between the rolling bearing 14 and the bushing 21, and between the bushing 21 and the countersunk hole of the platform step of the machine base 3. The gap value is ≤0.05mm. It was found that the 0.05mm feeler gauge could not be inserted into each contact surface, indicating that the contact surface fit gap value meets the accuracy requirements.

[0132] 6) Secure the three-piece cover of the machine base.

[0133] 6.1) Clean the working surface: Clean the contact surface of the machine base 3 platform, the outer surface of the upper half of the rolling bearing 14, etc., to ensure that there are no impurities, oil stains, etc.

[0134] 6.2) Use lifting machinery to suspend the platform cover of the machine base 3 and clean the contact surfaces (focusing on the countersunk hole and the inner circumferential surface of the bearing bush 21, the front and rear end sides, etc., to ensure that there are no impurities or oil stains).

[0135] 6.3) Installation and fastening: Suspend the top cover directly above the main drive mechanism base 3 platform, lower the hook at a uniform speed, and have the operator manually guide and straighten the top cover until it is accurately installed on the passive shaft device and base 3 platform. After calibrating the position, tighten the bolts and install the positioning pins.

[0136] 6.4) Clean up the work site: Clean up the tools and equipment (measuring instruments) used in the work site to create workstation conditions for subsequent work.

[0137] Example 2

[0138] This embodiment takes the LG-110H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ76~110mm as an example. Due to planned maintenance, the passive shaft device was completely replaced. The passive shaft device assembly had been completed in advance under offline conditions and is now being installed on the machine. The operation process includes: operation preparation → installation of the passive shaft device → axial positioning measurement → axial positioning installation → installation accuracy inspection → tightening of the machine base 3 cover. The installation accuracy of the passive shaft device is ensured to meet the technical requirements of cold-rolled pipe production, with the rolling center line K as the reference.

[0139] 1) Work preparation procedures:

[0140] 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.

[0141] 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.

[0142] 1.3) Preparation of Adjustment Spacing Ring 20: The adjustment spacing ring 20 is prepared and processed according to the improved requirements, and the side cut is changed from a bevel to an acute-angle tongue and groove (see...). Figure 6 As shown), new products can be processed and prepared according to the revised drawings. It should be noted that the thickness of the adjusting ring 20 should be reserved for processing. The allowance should be 2 to 3 mm, that is, the width of the adjusting ring 20 = 20 + 3 = 23 mm.

[0143] 2) The entire passive shaft assembly is installed on the machine (see...) Figure 2 , Figure 3 )

[0144] 2.1) Machine preparation: Clean all contact parts of the base 3 platform of the main drive mechanism (focusing on the inner circumferential surface of the split stepped hole and the annular groove, the shaft shoulder, etc., to ensure that there are no impurities, oil stains, etc.); clean the driven shaft mounting part (focusing on the outer circumferential surface of the rolling bearing 14, the positioning sleeve 16, the retaining ring 15, the side of the shaft shoulder, etc., to ensure that there are no impurities, oil stains, etc.).

[0145] 2.2) Installing the bearing shell 21: Since it was found that the bearing shell 21 on the countersunk hole of the machine base 3 platform was deformed and worn due to the damage of the rolling bearing 14 of the driven shaft device after opening the main drive mechanism, it is necessary to replace it with a new bearing shell 21; install the new split bearing shell 21 in the stepped hole of the machine base 3 platform and the stepped hole of the upper cover respectively, and use set screws for positioning.

[0146] 2.3) Suspended on the machine: Using lifting machinery (preferably a bridge crane), the entire passive shaft device is lifted and transported to the platform directly above the base 3 of the main drive mechanism of the cold rolling mill by passing a steel wire rope through the process hole of the left eccentric gear 11 and the right eccentric gear 12.

[0147] 2.4) Preliminary pre-assembly on the machine: The hook of the lifting machinery descends at a uniform speed. On the one hand, the operator directs the operation of the lifting machinery, and on the other hand, manually adjusts the position of the passive shaft device and the stepped hole (bearing shell 21) of the main drive base 3 platform. It is necessary to ensure that the retaining ring 15 on the inner side of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device is embedded in the annular groove on both sides of the countersunk hole of the base 3 platform, and the outer circumferential surface of the rolling bearing 14 is in contact with the inner circumferential surface of the bearing shell 21.

[0148] 2.5) Preliminary positioning of the passive shaft device: Use a crane to pull the device (or manually rotate it for small cold rolling mills) so that the passive shaft device rotates at least one revolution based on the countersunk hole of the machine base 3 platform to initially position it axially, and ensure that the eccentric parts of the left eccentric gear 11 and the right eccentric gear 12 are at the bottom due to gravity.

[0149] 3) Axial positioning measurement of the driven shaft assembly (see...) Figure 4 (As shown)

[0150] 3.1) Determine the rolling center line K: Use a laser rangefinder to generate a laser beam from the original reference of the seamless steel pipe cold rolling mill to calibrate the rolling center line K as the installation reference.

[0151] 3.2) Axial position determination: Based on the rolling center line K marked by the laser beam, measure the actual distances L1 and L2 between the inner end faces of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device and the rolling center line K, as well as the distance L between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device, and determine the offset direction and offset amount of the passive shaft device. Among them, the measured parameters are L = 750 mm, L1 = 378.5 mm, and L2 = 371.5 mm. At this time, L1 > L2 indicates that the passive shaft device is offset to the left, and the offset amount = L1 - 1 / 2L = 378.5 - 750 / 2 = 3.5 mm.

[0152] 3.3) Axial position correction: Correction is performed based on the measured values ​​of L1 = 378.5mm and L2 = 371.5mm. A lifting machine is used to slightly suspend the shaft (preferably with a gap of 2-5mm between the rolling bearing 14 and the bushing 21). Correction is performed according to the offset direction and amount determined in step 3.2). The driven shaft device is manually pried to correct axial alignment in the direction of the rightward eccentric gear, ensuring L = L1 + L2, L1 ≈ L2, and an error value ≤ 1.0mm. After correction, the lifting machine hook is lowered, and the rolling bearing 14 and bushing 21 return to contact. L1 = 375.5mm and L2 = 374.5mm are measured again. At this point, L1 > L2, indicating that the driven shaft device has shifted to the left. The offset amount = L1 - 1 / 2L = 375.5 - 750 / 2 = 0.50mm, which meets the requirement of an error value ≤ 1.0mm.

[0153] 3.4) Determine the width value of the adjusting distance ring 20: Use vernier calipers and gauge blocks to measure the axial direction of the passive shaft device after recalibration and positioning. The main measurements are the distance values ​​b1 and b2 between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 and the two sides of the machine base 3 platform. The distance values ​​a1 and a2 between the left rolling bearing, the right rolling bearing and the shoulder of the stepped hole of the machine base 3 platform are calculated with the rolling center line K as the reference. a1=(L-L3) / 2-b1-cd, a2=(L-L3) / 2-b2-cd. On-site measurements showed b1 = 61.2mm, b2 = 58.8mm, L3 = 150mm, the width c of retaining ring 15 was 40mm, and the width b of the outer ring of rolling bearing 14 was 180mm. Calculations showed a1 = (L-L3) / 2 - b1 - cd = (750-150) / 2 - 61.2 - 40 - 180 = 18.8mm, and a2 = (L-L3) / 2 - b2 - cd = (750-150) / 2 - 58.8 - 40 - 180 = 21.2mm. Simultaneously, on-site measurements showed a1 = 19.4mm and a2 = 21mm. In cases where the measured values ​​differ from the calculated values, the calculated values ​​shall prevail.

[0154] 4) Axial positioning and installation of the driven shaft assembly (see...) Figure 3 )

[0155] 4.1) Matching the left and right adjustment distance rings: According to the a1 and a2 parameter values ​​obtained from the calculation model, perform precision grinding. The thickness value of the adjustment distance ring 20 must meet the calculated values ​​of a1 and a2, and the error value ≤ 0.05mm. Therefore, the width value of the distance ring is matched with a1 = 18.8 ± 0.02mm and a2 = 21.2 ± 0.02mm.

[0156] 4.2) Install axial positioning elements: Install two adjusting spacer rings with widths of a1 = 18.8 ± 0.02 mm and a2 = 21.2 ± 0.02 mm, respectively, in the left-right direction between the shoulder of the stepped hole of the machine base 3 platform and the rolling bearing 14. During installation, ensure that the tongue and groove of the adjusting spacer ring 20 are flush and properly engaged.

[0157] 4.3) Adjusting the axial positioning accuracy of the spacer ring 20: Use a 0.02-0.05mm feeler gauge to measure the clearance between the two sides of the spacer ring 20 and the rolling bearing 14 and the shoulder of the stepped hole of the platform of the machine base 3. The clearance values ​​at both locations should not exceed 0.05mm. If they exceed 0.05mm, it indicates that there is an error in the calculation accuracy, and it is necessary to re-measure, recalculate, process, and reinstall.

[0158] 5) Installation accuracy inspection

[0159] 5.1) Axial positioning accuracy inspection: The distance between the inner side of the left eccentric gear 11 and the right eccentric gear 12 and the rolling center line K was measured using a laser rangefinder. The distance error should be ≤1.0mm. The actual measurement showed that L1 = 375.6mm and L2 = 374.4mm. The entire passive shaft device was offset to the left eccentric gear direction by 0.60mm, which meets the error accuracy technical requirements.

[0160] 5.2) Radial (circumferential) installation accuracy inspection: Use a 0.02-0.05mm feeler gauge to inspect the contact surface fit between the rolling bearing 14 and the bushing 21, and between the bushing 21 and the countersunk hole of the platform step of the machine base 3. The gap value is ≤0.05mm. It was found that the 0.05mm feeler gauge could not be inserted into each contact surface, indicating that the contact surface fit gap value meets the accuracy requirements.

[0161] 6) Secure the three-piece cover of the machine base.

[0162] 6.1) Clean the working surface: Clean the contact surface of the machine base 3 platform, the outer surface of the upper half of the rolling bearing 14, etc., to ensure that there are no impurities, oil stains, etc.

[0163] 6.2) Use lifting machinery to suspend the platform cover of the machine base 3 and clean the contact surfaces (focusing on the countersunk hole and the inner circumferential surface of the bearing bush 21, the front and rear end sides, etc., to ensure that there are no impurities or oil stains).

[0164] 6.3) Installation and fastening: Suspend the top cover directly above the main drive mechanism base 3 platform, lower the hook at a uniform speed, and have the operator manually guide and straighten the top cover until it is accurately installed on the passive shaft device and base 3 platform. After calibrating the position, tighten the bolts and install the positioning pins.

[0165] 6.4) Clean up the work site: Clean up the tools and equipment (measuring instruments) used in the work site to create workstation conditions for subsequent work.

[0166] Example 3

[0167] This embodiment takes the LG-60H two-roll periodic seamless steel pipe cold rolling mill with a finished product specification of φ38~60mm as an example. Due to planned maintenance, the passive shaft device was completely replaced. The passive shaft device assembly had been completed in advance under offline conditions and is now being installed on the machine. The operation process includes: operation preparation → installation of the passive shaft device → axial positioning measurement → axial positioning installation → installation accuracy inspection → tightening of the machine base 3 cover. The installation accuracy of the passive shaft device is ensured to meet the technical requirements of cold-rolled pipe with the rolling center line K as the reference.

[0168] 1) Work preparation procedures:

[0169] 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.

[0170] 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.

[0171] 1.3) Preparation of Adjustment Spacing Ring 20: The adjustment spacing ring 20 is prepared and processed according to the improved requirements, and the side cut is changed from a bevel to an acute-angle tongue and groove (see...). Figure 6 As shown), new products can be processed and prepared according to the revised drawings. It should be noted that the thickness of the adjusting ring 20 should be reserved with a machining allowance of 2 to 3 mm, that is, the width of the adjusting ring 20 = 20 + 2 = 22 mm.

[0172] 2) The entire passive shaft assembly is installed on the machine (see...) Figure 2 , Figure 3 )

[0173] 2.1) Machine preparation: Clean all contact parts of the main drive mechanism base 3 platform (focusing on the inner circumferential surface of the split stepped hole and annular groove, shaft shoulder, etc., to ensure there are no impurities, oil stains, etc.); clean the driven shaft mounting area (focusing on the outer circumferential surface of the rolling bearing 14, positioning sleeve 16, retaining ring 15, shaft shoulder side, etc., to ensure there are no impurities, oil stains, etc.).

[0174] 2.2) Installing the bearing shell 21: Since it was found that the bearing shell 21 on the countersunk hole of the machine base 3 platform was deformed and worn due to the damage of the rolling bearing 14 of the driven shaft device after opening the main drive mechanism, it is necessary to replace it with a new bearing shell 21; install the new split bearing shell 21 in the stepped hole of the machine base 3 platform and the stepped hole of the upper cover respectively, and use set screws for positioning.

[0175] 2.3) Suspended on the machine: Using lifting machinery (preferably a bridge crane), the entire passive shaft device is lifted and transported to the platform directly above the base 3 of the main drive mechanism of the cold rolling mill by passing a steel wire rope through the process hole of the left eccentric gear 11 and the right eccentric gear 12.

[0176] 2.4) Preliminary pre-assembly on the machine: The hook of the lifting machinery descends at a uniform speed. On the one hand, the operator directs the operation of the lifting machinery, and on the other hand, manually adjusts the position of the passive shaft device and the stepped hole (bearing shell 21) of the main drive base 3 platform. It is necessary to ensure that the retaining ring 15 on the inner side of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device is embedded in the annular groove on both sides of the countersunk hole of the base 3 platform, and the outer circumferential surface of the rolling bearing 14 is in contact with the inner circumferential surface of the bearing shell 21.

[0177] 2.5) Preliminary positioning of the passive shaft device: Use a crane to pull the device (or manually rotate it for small cold rolling mills) so that the passive shaft device rotates at least one revolution based on the countersunk hole of the machine base 3 platform to initially position it axially, and ensure that the eccentric parts of the left eccentric gear 11 and the right eccentric gear 12 are at the bottom due to gravity.

[0178] 3) Axial positioning measurement of the driven shaft assembly (see...) Figure 4 (As shown)

[0179] 3.1) Determine the rolling center line K: Use a laser rangefinder to generate a laser beam from the original reference of the seamless steel pipe cold rolling mill to calibrate the rolling center line K as the installation reference.

[0180] 3.2) Axial position determination: Based on the rolling center line K marked by the laser beam, measure the actual distances L1 and L2 between the inner end faces of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device and the rolling center line K, as well as the distance L between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 of the passive shaft device, and determine the offset direction and offset amount of the passive shaft device. Among them, the measured parameters are L = 700 mm, L1 = 347.4 mm, and L2 = 352.6 mm. At this time, L1 < L2 indicates that the passive shaft device is offset to the right, and the offset amount = L2 - 1 / 2L = 352.6 - 700 / 2 = 2.6 mm.

[0181] 3.3) Axial position correction: Correction is performed based on the measured values ​​of L1 = 347.4 mm and L2 = 352.6 mm. A lifting machine is used to slightly suspend the shaft (with a clearance of 2-5 mm between the rolling bearing 14 and the bushing 21). The correction is performed according to the offset direction and amount determined in step 3.2). The driven shaft device is manually pried to correct axial alignment in the direction of the leftward eccentric gear, ensuring L = L1 + L2, L1 ≈ L2, and an error value ≤ 1.0 mm. After correction, the lifting machine hook is lowered, and the rolling bearing 14 and bushing 21 return to contact. L1 = 350.2 mm and L2 = 349.8 mm are measured again. At this point, L1 > L2, indicating that the driven shaft device has shifted to the left. The offset amount = L1 - 1 / 2L = 350.2 - 700 / 2 = 0.20 mm, which meets the requirement of an error value ≤ 1.0 mm.

[0182] 3.4) Determine the width value of the adjusting distance ring 20: Use vernier calipers and gauge blocks to measure the axial direction of the passive shaft device after recalibration and positioning. The main measurements are the distance values ​​b1 and b2 between the inner sides of the left eccentric gear 11 and the right eccentric gear 12 and the two sides of the machine base 3 platform. The distance values ​​a1 and a2 between the left rolling bearing, the right rolling bearing and the shoulder of the stepped hole of the machine base 3 platform are calculated with the rolling center line K as the reference. a1=(L-L3) / 2-b1-cd, a2=(L-L3) / 2-b2-cd. On-site measurements showed b1 = 55.4 mm, b2 = 54.6 mm, L3 = 150 mm, the width c of retaining ring 15 was 40 mm, and the width b of the outer ring of rolling bearing 14 was 160 mm. Calculations showed a1 = (L-L3) / 2 - b1 - cd = (700-150) / 2 - 55.4 - 40 - 160 = 19.6 mm, and a2 = (L-L3) / 2 - b2 - cd = (700-150) / 2 - 54.6 - 40 - 160 = 20.4 mm. Simultaneously, on-site measurements showed a1 = 19.4 mm and a2 = 21 mm. In cases where the measured values ​​differ from the calculated values, the calculated values ​​shall prevail.

[0183] 4) Axial positioning and installation of the driven shaft assembly (see...) Figure 3 )

[0184] 4.1) Matching the left and right adjustment distance rings: According to the a1 and a2 parameter values ​​obtained from the calculation model, perform precision grinding. The thickness value of the adjustment distance ring 20 must meet the calculated values ​​of a1 and a2, and the error value ≤ 0.05mm. Therefore, the width value of the distance ring is matched with a1 = 19.6 ± 0.02mm and a2 = 20.4 ± 0.02mm.

[0185] 4.2) Install axial positioning elements: Install two adjusting spacer rings with widths of a1 = 19.6 ± 0.02 mm and a2 = 20.4 ± 0.02 mm, respectively, in the left and right directions between the shoulder of the stepped hole of the machine base 3 platform and the rolling bearing 14. During installation, ensure that the tongue and groove of the adjusting spacer ring 20 are flush and properly engaged.

[0186] 4.3) Adjusting the axial positioning accuracy of the spacer ring 20: Use a 0.02-0.05mm feeler gauge to measure the clearance between the two sides of the spacer ring 20 and the rolling bearing 14 and the shoulder of the stepped hole of the platform of the machine base 3. The clearance values ​​at both locations should not exceed 0.05mm. If they exceed 0.05mm, it indicates that there is an error in the calculation accuracy, and it is necessary to re-measure, recalculate, process, and reinstall.

[0187] 5) Installation accuracy inspection

[0188] 5.1) Axial positioning accuracy inspection: The distance between the inner side of the left eccentric gear 11 and the right eccentric gear 12 and the rolling center line K was measured using a laser rangefinder. The distance error should be ≤1.0mm. The actual measurement showed that L1 = 350.3mm and L2 = 349.7mm. The entire passive shaft device was offset to the left eccentric gear direction by 0.30mm, which meets the error accuracy technical requirements.

[0189] 5.2) Radial (circumferential) installation accuracy inspection: Use a 0.02-0.05mm feeler gauge to inspect the contact surface fit between the rolling bearing 14 and the bushing 21, and between the bushing 21 and the countersunk hole of the platform step of the machine base 3. The gap value is ≤0.05mm. It was found that the 0.05mm feeler gauge could not be inserted into each contact surface, indicating that the contact surface fit gap value meets the accuracy requirements.

[0190] 6) Secure the three-piece cover of the machine base.

[0191] 6.1) Clean the working surface: Clean the contact surface of the machine base 3 platform, the outer surface of the upper half of the rolling bearing 14, etc., to ensure that there are no impurities, oil stains, etc.

[0192] 6.2) Use lifting machinery to suspend the platform cover of the machine base 3 and clean the contact surfaces (focusing on the countersunk hole and the inner circumferential surface of the bearing bush 21, the front and rear end sides, etc., to ensure that there are no impurities or oil stains).

[0193] 6.3) Installation and fastening: Suspend the top cover directly above the main drive mechanism base 3 platform, lower the hook at a uniform speed, and have the operator manually guide and straighten the top cover until it is accurately installed on the passive shaft device and base 3 platform. After calibrating the position, tighten the bolts and install the positioning pins.

[0194] 6.4) Clean up the work site: Clean up the tools and equipment (measuring instruments) used in the work site to create workstation conditions for subsequent work.

[0195] In summary, the present invention provides a method for installing the passive shaft device of the main drive mechanism in a seamless steel pipe cold rolling mill, representing a technical improvement over the existing operation and maintenance methods of the main drive mechanism in a two-roll periodic seamless steel pipe cold rolling mill. The method features a reasonable process design, compact flow connections, high axial positioning accuracy of the passive shaft device (axial positioning error ≤1.0mm), good stability, convenient operation, and significant anti-deformation escape effect. While ensuring the accuracy of the passive shaft device installation, it meets the technical requirements for cold-rolling seamless steel pipes of high-alloy and high-strength new steel grades. Installation quality is controlled and stable, making it practical, efficient, safe, and reliable. By optimizing and adjusting the structure of the spacer ring, and adopting a tongue-and-groove shape, the stability under axial load is improved while fulfilling the installation guidance function, effectively preventing deformation escape. Using the rolling centerline as a reference, the width value of the spacer ring is determined and adjusted through a measurement and calculation model, improving the axial positioning accuracy. The measurement and calculation model is reasonably designed, convenient to operate, requires minimal experience and skills from operators, facilitates standardized operation, and is practical and efficient. Through practical application in production, the passive shaft device has shown a significant reduction in operational failures, effectively ensuring its service life and operational quality. It has also reduced equipment downtime and maintenance resource consumption, demonstrating a certain effect in eliminating malfunctions, reducing costs, and promoting production, generating economic benefits of over 500,000 yuan annually. Furthermore, its strong versatility makes it valuable for improving the operation and maintenance technology of the main drive mechanism of a two-roll periodic seamless steel pipe cold rolling mill, offering valuable insights and applications.

[0196] 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 installing a driven shaft device of a main drive mechanism of a seamless steel pipe cold rolling mill, characterized in that, It comprises the following steps: (1) preparation for operation; (2) overall mounting of passive shaft device: the overall passive shaft device is suspended above the base of the main transmission mechanism for preliminary pre-assembly and positioning; (3) axial positioning measurement of the passive shaft device: the axial positioning of the passive shaft device is performed with the rolling center line as the reference, and the width of the left and right adjusting distance rings is determined; (4) axial positioning installation of the passive shaft device: the left and right adjusting distance rings are prepared and installed, and the axial positioning accuracy of the left and right adjusting distance rings is measured; (5) installation accuracy inspection; (6) base cover fastening, In the step (3), the axial positioning measurement of the passive shaft device further comprises: (3.1) determining the rolling center line, forming a laser beam from the original reference of the seamless steel pipe cold rolling mill with a laser range finder, and calibrating the rolling center line; (3.2) axial position measurement, according to the rolling center line calibrated by the laser beam, measuring the actual distance values L1, L2 of the inner side faces of the left and right eccentric gears of the passive shaft device from the rolling center line and the distance L between the inner side faces of the left and right eccentric gears of the passive shaft device, and judging the offset direction and amount of the passive shaft device; (3.3) axial position correction, according to the measured values of L1 and L2, the axial deviation correction is performed to ensure that the distance L between the inner side faces of the left and right eccentric gears of the passive shaft device is L1+L2, and L1≈L2, and the error value is not more than 1.0mm; (3.4) determining the width value of the adjusting distance ring, measuring the axial position of the passive shaft device after axial correction, obtaining the distance values b1, b2 between the inner side faces of the left and right eccentric gears of the passive shaft device and the two side faces of the base platform, and calculating the distance values a1, a2 between the left and right rolling bearings and the shoulder of the stepped hole of the base platform with the rolling center line as the reference, wherein a1= (L-L3) / 2-b1-c-d, a2= (L-L3) / 2-b2-c-d, L3 is the width value of the stepped hole shoulder between the split type bearing bush of the passive shaft device and the base platform of the main transmission mechanism, c is the width value of the retaining ring, and d is the width value of the outer ring of the rolling bearing, and a1, a2 are the width values of the adjusting distance ring for the left and right eccentric gears.

2. The seamless steel pipe cold rolling mill main transmission mechanism passive shaft device mounting method according to claim 1, wherein In the step (1), the preparation for operation comprises safety technology disclosure, implementation of on-site safety precautions, preparation of tools and materials, spare parts and materials cleaning and drawing checking, and adjusting distance ring modification.

3. The seamless steel pipe cold rolling mill main transmission mechanism passive shaft device mounting method according to claim 2, wherein In the step (1), the split opening on one side of the adjusting distance ring is an acute angle split opening, and the adjusting distance ring has a machining allowance when being processed.

4. The method according to claim 3, wherein the main drive mechanism of the seamless pipe cold rolling mill is a passive shaft device, and the installation method is characterized in that, The machining allowance is 2-3mm.

5. The method according to claim 1, wherein the main drive mechanism of the seamless pipe cold rolling mill is a passive shaft device, and the installation method is characterized in that, In the step (2), the overall mounting of the passive shaft device further comprises: (2.1) preparation for mounting; (2.2) installing the bearing bush, installing the split type bearing bush in the stepped hole of the base platform and the stepped hole of the upper cover; (2.3) Suspended on the machine, the whole set of passive shaft device is lifted and transported to the top of the main transmission mechanism platform; (2.4) Preliminary preloading on the machine, adjusting the position of the passive shaft device and the stepped hole of the main transmission mechanism platform, so that the left eccentric gear and the right eccentric gear inside the ring are embedded in the annular groove on both sides of the sink hole of the platform, and the outer circumference of the rolling bearing is in contact with the inner circumference of the bearing bush; (2.5) Preliminary positioning of the passive shaft device, at least one circle is rotated based on the sink hole of the platform for axial preliminary positioning, and the left eccentric gear and the right eccentric gear of the passive shaft device are ensured to be at the lowest end due to gravity.

6. The method according to claim 1, wherein the main drive mechanism of the seamless pipe cold rolling mill is a passive shaft device, and the installation method is characterized in that, In the step (3.2), during the correction, the correction is made according to the offset direction and the offset amount. When L1>L2, it indicates that the passive shaft device is offset to the left side, and the offset amount is L1-1 / 2L; when L1L2, it indicates that the passive shaft device is offset to the right side, and the offset amount is L2-1 / 2L.

7. The method according to claim 1, wherein the main drive mechanism of the seamless pipe cold rolling mill is a passive shaft device, and the installation method is characterized in that, In the step (3.3), when the passive shaft device is suspended, the gap between the rolling bearing and the bearing bush is 2-5mm.

8. The method according to claim 1, wherein the main drive mechanism of the seamless pipe cold rolling mill is installed on the machine with the passive shaft device, characterized in that, In the step (4), the axial positioning and installation of the passive shaft device further comprises: (4.1) making left and right adjusting distance rings, and performing precision machining on the adjusting distance rings according to a1 and a2 obtained in the step (3) to ensure that the error value of the width of the machined adjusting distance ring is less than or equal to 0.05mm; (4.2) installing the axial positioning element, and installing the precision machined adjusting distance ring between the corresponding stepped hole shaft shoulder of the platform and the rolling bearing, and ensuring that it is installed in place; (4.3) adjusting the axial positioning precision of the adjusting distance ring, using a 0.02-0.05mm feeler gauge to measure the gap value between the adjusting distance ring on both sides and the rolling bearing and the stepped hole shaft shoulder of the platform, and ensuring that the gap value is not greater than 0.05mm.

9. The method according to claim 1, wherein the main drive mechanism of the seamless pipe cold rolling mill is installed on the machine with the passive shaft device, characterized in that, In the step (5), the installation precision inspection further comprises: (5.1) axial positioning precision inspection, using a laser range finder to detect the distance between the inner side of the left eccentric gear and the right eccentric gear and the rolling center line, and the distance error is less than or equal to 1.0mm; (5.2) radial installation precision inspection, using a 0.02-0.05mm feeler gauge to inspect the contact surface fitting condition of the rolling bearing and the bearing bush, and the bearing bush and the stepped sink hole of the platform, and ensuring that the gap value is less than or equal to 0.05mm.

10. The method according to claim 1, wherein the main drive mechanism of the seamless steel pipe cold rolling mill is installed on the machine with the passive shaft device, characterized in that: In the step (6), the machine cover fastening further comprises cleaning the work surface, cleaning the contact surface of the machine platform and the passive shaft device, suspending and installing the cover of the machine platform, and cleaning the work site.

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