A large shaft connecting bolt anti-loosening device

Abstract

The present application relates to the technical fields of mechanical transmission and fastener anti-loosening, and discloses a large-scale shaft connecting bolt anti-loosening device. The device comprises a rigid sleeve ring and multiple independent anti-loosening sleeves. The rigid sleeve ring is sleeved on the outer side of the flange end face and is provided with installation positions corresponding to the flange bolt holes. Each independent anti-loosening sleeve is provided with a constraint structure for sleeving and circumferentially constraining the nut. The independent anti-loosening sleeve further comprises a hinge bolt. The first end of the hinge bolt is hingedly connected with the independent anti-loosening sleeve, and the second end penetrates through the corresponding structure on the rigid sleeve ring and is fastened by a locking nut. After the locking nut is tightened, each independent anti-loosening sleeve is rigidly connected with the rigid sleeve ring and forms a whole-circle linkage through the rigid sleeve ring. The present application realizes the unity of rigid linkage locking of the whole-circle multiple bolts and independent adjustment of each nut, has the advantages of load uniform distribution, double anti-loosening and modular quick disassembly, and is particularly suitable for heavy load anti-loosening working conditions of large-scale universal shaft flange connecting bolts.

Description

Technical Field

[0001] This invention relates to the field of mechanical transmission and fastener anti-loosening technology, specifically an anti-loosening device for large shaft connecting bolts. Background Technology

[0002] In steel rolling production lines, large metallurgical equipment, and heavy machinery transmission systems, large universal joints serve as crucial transmission components, playing a vital role in transferring drive torque from the motor to the rolls. Taking a typical large rolling mill universal joint as an example, its flange connections often utilize M36 or higher specification, 12.9 grade high-strength bolts, numbering up to 24 or more, with bolt preload typically in the hundreds of kilonewtons range. During the rolling mill process, while transmitting enormous torque, the universal joint also endures the intense impact loads generated during the moment of steel biting, the cyclic alternating stresses during rolling, and the inherent wide-frequency vibrations of the equipment, resulting in extremely harsh operating conditions. Under the long-term influence of these complex loads, the loosening of flange connection bolts remains a major technical challenge hindering stable equipment operation, potentially leading to serious equipment accidents such as bolt breakage and universal joint detachment.

[0003] Currently, the industry mainly adopts the following technical solutions for preventing loosening of bolts in large flange connections.

[0004] Firstly, there are single-nut anti-loosening solutions. Mechanical anti-loosening methods, such as cotter pins and slotted nuts, locking washers, and connecting wires, prevent relative rotation by increasing mechanical constraints. However, under large-size (M30 and above) and high preload conditions, the locking torque is limited, making it difficult to withstand strong impact and vibration loads, and the installation and operation are cumbersome. Friction-based anti-loosening methods, such as spring washers and double nuts against each other, rely on increasing the frictional resistance of the thread pair to prevent loosening. However, under heavy load conditions, strong vibrations can cause the frictional resistance to gradually decrease under alternating loads, leading to anti-loosening failure. Wedge-shaped threads have a good anti-loosening effect, but the thread processing is complex and costly, and it requires strict fitting accuracy, making it unsuitable for on-site replacement and maintenance.

[0005] Secondly, there's the integrated anti-loosening solution. Anti-loosening chains connect nuts in series, relying on lateral contact between adjacent nuts for linkage. However, the chain is a flexible connection with limited load-bearing capacity, making it difficult to transmit large locking torques, and the preload distribution is uneven. The integrated locking sleeve structure connects multiple anti-loosening sleeves into a single unit via a ring, achieving rigid linkage. However, since each anti-loosening sleeve and ring is mostly a single unit, independent adjustment and secondary locking of each nut are not possible, making installation and disassembly difficult and requiring high manufacturing precision.

[0006] Thirdly, there are anti-loosening solutions involving articulated structures. Some existing technologies use the articulated transmission principle to achieve single-point anti-loosening locking, such as using an articulated rod to drive a cylindrical rod to push a positioning block, thereby achieving elastic clamping or locking of the nut. Its essence is the technical path of "the motion mechanism pushes the positioning block to lock at a single point," which contributes to the anti-loosening of a single nut, but does not involve a rigid linkage design for the coordinated anti-loosening of multiple bolts around the entire circle.

[0007] In summary, existing anti-loosening technologies generally suffer from the following drawbacks in the actual working conditions of large universal joint flange connections: single-point locking schemes cannot achieve balanced load distribution across the entire ring, making them prone to loosening at a single point under impact and triggering a chain reaction; flexible linkage schemes have limited load-bearing capacity and poor consistency in preload; rigid linkage schemes lack independent adjustment and secondary locking functions for each nut, making maintenance inconvenient; most schemes are single anti-loosening mechanisms, lacking dual protection; and most are general-purpose designs, not specifically optimized for the heavy-duty scenario of M36×24 pieces and 12.9 grade high-strength bolts. Therefore, there is an urgent need for a dedicated anti-loosening device that can simultaneously achieve rigid linkage across the entire ring, independent and precise locking of each nut, and is easy to install and maintain on-site. Summary of the Invention

[0008] The purpose of this invention is to provide an anti-loosening device for large shaft connecting bolts, so as to solve the problem of loosening of large universal joint flange connecting bolts under long-term action of complex loads as mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A device for preventing loosening of large shaft connecting bolts, used for locking and preventing loosening of flange connecting bolts of large universal joints, wherein the flange has multiple bolt holes along the circumferential direction, and each bolt hole is used to insert a flange connecting bolt and fit with a nut, comprising:

[0011] A rigid collar is fitted onto the outer side of the flange end face, and the rigid collar has mounting positions along the circumferential direction that correspond one-to-one with the bolt holes;

[0012] Multiple independent anti-loosening sleeves are provided, each of which is correspondingly provided with one of the flange connecting bolts. Each independent anti-loosening sleeve has a constraint structure for fitting and circumferentially restraining the nut. Each independent anti-loosening sleeve also includes a hinge bolt, the first end of which is hinged to the independent anti-loosening sleeve, and the second end of which passes through a corresponding structure on the rigid collar and is fastened by a lock nut.

[0013] After the locking nut is tightened, the independent anti-loosening sleeve and the rigid collar form a rigid connection, and the independent anti-loosening sleeves are linked together by the rigid collar.

[0014] As a further preferred technical solution, the rigid collar is a split-type combined collar, which is assembled from at least two sector-shaped segments connected end to end along the circumferential direction; each sector-shaped segment has connecting lugs at both ends, and the connecting lugs of adjacent sector-shaped segments are detachably and fixedly connected by connecting bolts passing through the connecting bolt holes of the collar; each sector-shaped segment has bolt holes that correspond one-to-one with the number and position of the bolt holes of the flange it covers, and the flange connecting bolts pass through the bolt holes to press and fix the sector-shaped segments to the flange end face.

[0015] As a further preferred technical solution, each of the sector segments has a stepped structure on its inner edge end face. After the sector segments are assembled, the stepped structures together form a complete annular stepped surface. The annular stepped surface is used to fit against the flange end face to realize the axial positioning and load transfer of the rigid collar.

[0016] As a further preferred technical solution, the rigid collar is provided with an axially penetrating U-shaped slot for the hinge bolt corresponding to each of the mounting positions, and the second end of the hinge bolt is engaged or disengaged from the side of the U-shaped slot.

[0017] As a further preferred technical solution, the U-shaped bayonet of the hinge bolt has a recessed countersunk hole platform at one end near the outer edge of the rigid collar. After the locking nut is tightened, it is at least partially embedded in the countersunk hole platform, and the side wall of the countersunk hole platform forms a circumferential constraint on the locking nut.

[0018] As a further preferred technical solution, the independent anti-loosening sleeve includes a hexagonal sleeve body, a hinge pin, and a hinge bolt. The hexagonal sleeve body has an inner hexagonal hole for fitting and circumferentially restraining the nut. A deflecting boss is provided on the radially outer side of the hexagonal sleeve body, and a first pin hole is formed on the deflecting boss. The first end of the hinge bolt has a double-fork structure, and a second pin hole is formed on the two fork arms of the double-fork structure. The hinge pin passes through the second pin hole and the first pin hole, and hinges the hinge bolt to the hexagonal sleeve body.

[0019] As a further preferred technical solution, the side dimension of the inner hexagonal hole of the hexagonal sleeve is the nominal outer hexagonal dimension of the nut plus 0.2mm to 0.5mm, the single-sided fitting clearance between the hexagonal sleeve and the nut is not greater than 0.3mm, and the axial length of the hexagonal sleeve is 5mm to 10mm greater than the thickness of the nut.

[0020] As a further preferred technical solution, the axial length of the hexagonal sleeve is 8 mm greater than the thickness of the nut.

[0021] As a further preferred technical solution, each of the independent anti-loosening sleeves is independently connected to the rigid collar only through its corresponding hinge bolt, and there is no direct connection between adjacent independent anti-loosening sleeves; when disassembling any independent anti-loosening sleeve, it is only necessary to loosen the corresponding locking nut to remove the independent anti-loosening sleeve from the corresponding nut.

[0022] As a further preferred technical solution, the rigid collar is made of alloy steel with a yield strength of not less than 750 MPa, and the thickness of the rigid collar is 25 mm to 40 mm; the hinge bolt is of M12 to M20, with a performance grade of not less than 10.9, and the tightening torque of the hinge bolt is 80 N·m to 200 N·m; the hexagonal sleeve is made of 40Cr or 42CrMo alloy steel, with a heat treatment hardness of HRC38 to 42, and the minimum wall thickness of the hexagonal sleeve is not less than 8 mm; the anti-loosening device is suitable for large shaft flange connections with bolt specifications of M30 to M48 and a bolt quantity of 12 to 32 pieces.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] First, by connecting all the anti-loosening sleeves into one unit through the whole ring rigid collar, the rigid linkage locking of the whole ring multi-bolt is realized, which improves the defects of uneven load of single point scheme and insufficient bearing capacity of flexible scheme, and reduces the preload unevenness from ±25% to ±30% to within ±10%.

[0025] Secondly, by rigidly connecting each anti-loosening sleeve to the collar via independent hinge bolts, each nut can be independently locked and adjusted, solving the problem that the integral collar solution cannot independently repair a single bolt. The disassembly and assembly time of a single anti-loosening component is no more than 3 minutes, reducing downtime by more than 70%.

[0026] Third, by forming a dual constraint mechanism through the rigid linkage of the whole circle and the independent hinge locking, the defect of the whole failure is overcome by the failure of a single anti-loosening mechanism. Under the extreme condition that the preload of the hinge bolt decreases by 50%, the rigid constraint of the whole circle can still limit the loosening angle of the nut to within 5°.

[0027] Fourth, by dividing the ring into four sector-shaped segments and using hinged bolts to snap into the side of the axial opening, the weight of a single piece and the difficulty of installation are reduced. No large lifting equipment or additional flange processing is required. The initial installation time for the entire ring is no more than 25 minutes, and the disassembly and assembly of a single component is no more than 3 minutes. This avoids the problem of difficult tensioning operation of chain solutions and reduces the difficulty of on-site maintenance and safety risks. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the assembly of an anti-loosening device for large shaft connecting bolts according to the present invention; Figure 2 This is a schematic diagram of the overall structure of an anti-loosening device for large shaft connecting bolts according to the present invention; Figure 3 This is a schematic diagram of a segment of the rigid collar of the present invention; Figure 4 This is a schematic diagram of the overall structure of the anti-loosening sleeve of the present invention; Figure 5 A structural schematic diagram of a rigid collar from the first perspective; Figure 6 This is a structural schematic diagram from a second perspective of the rigid collar.

[0029] In the diagram: 1: Long shaft; 21: Rigid collar; 211: Connecting lug; 212: Bolt hole; 213: Hinged bolt U-shaped bayonet; 214: Bayonet countersunk platform; 215: Collar connecting bolt hole; 23: Independent anti-loosening sleeve; 231: Hexagonal sleeve; 232: Hinged pin; 233: Hinged bolt; 234: Hexagonal nut; 22: Flange connecting bolt; 3. Reducer. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides an anti-loosening device for large shaft connecting bolts, used for locking and preventing loosening of flange connecting bolts on large universal joints. The large universal joint, a key transmission component in a steel rolling mill production line, is connected at one end to the flat head of a rolling mill roll via a flange, and at the other end to the output shaft of a reducer 3 via a flange. Multiple bolt holes are evenly spaced along the circumference of the flange, each hole housing a flange connecting bolt 22 and fitted with a nut. The flange connecting bolts 22 are typically M36 or higher specification, grade 12.9 high-strength bolts, and up to 24 pieces are used, requiring extremely high preload.

[0032] Please see Figures 1 to 6 The anti-loosening device in this embodiment includes a rigid collar 21 and multiple independent anti-loosening sleeves 23.

[0033] A rigid collar 21 is fitted onto the outer side of the flange end face. In a preferred embodiment of the invention, the rigid collar 21 is a split-type composite collar, assembled from at least two sector-shaped segments joined end-to-end along the circumferential direction. Each sector-shaped segment has connecting lugs 211 at both ends, and adjacent sector-shaped segments are detachably and securely connected by connecting bolts passing through the collar connecting bolt holes 215. The connecting bolts can be M12 to M16, 10.9 grade high-strength bolts, equipped with spring washers for anti-loosening. Each sector-shaped segment has bolt holes 212 corresponding one-to-one with the number and position of the bolt holes on the flange it covers. The flange connecting bolts 22 pass through the bolt holes 212 to press and fix the sector-shaped segments to the flange end face, thus forming circumferential fixation and axial compression of the rigid collar 21 on the flange, eliminating the need for additional positioning structures on the flange.

[0034] Each sector segment has a stepped structure on its inner edge end face. After assembly, the stepped structures of all sector segments together form a complete annular stepped surface. This annular stepped surface fits against the flange end face, bearing the axial positioning and load transmission of the rigid collar 21. During the operation of the universal joint, this stepped structure effectively prevents the rigid collar 21 from moving towards the shaft end. The rigid collar 21 is made of alloy steel such as 42CrMo or 40CrNiMoA with a yield strength of not less than 750MPa, with a thickness of 25mm to 40mm. It is heat-treated to ensure the rigidity and load-bearing capacity of the entire collar. The flatness of the rear end face of the assembled collar is not greater than 0.1mm to ensure the consistency of the installation of each anti-loosening sleeve. The rigid collar 21 has mounting positions along the circumference that correspond one-to-one with the flange bolt holes.

[0035] Please see Figure 3 and Figure 5 The rigid collar 21 has an axially penetrating U-shaped slot 213 for each mounting position. The U-shaped slot 213 extends radially inward from the outer edge of the fan-shaped segment to near the outer wall of the mounting position. Its width is greater than the diameter of the shank at the second end of the hinge bolt 233, so that the second end of the hinge bolt 233 can be engaged or disengaged from the side of the U-shaped slot 213 without needing to be axially inserted from both ends.

[0036] The hinge bolt U-shaped bayonet 213 has a recessed countersunk platform 214 at one end near the outer edge of the rigid collar 21. The countersunk platform 214 is a circular recess with a diameter larger than the opposite side dimension of the lock nut and a depth of 2mm to 4mm. After the lock nut is tightened, it is at least partially embedded in the countersunk platform 214. The sidewall of the countersunk platform 214 forms a circumferential constraint on the lock nut, making it less likely to loosen due to vibration. Compared with traditional friction-based anti-loosening solutions, this countersunk platform, relying on the mechanical constraint principle of embedding and sidewall limiting, significantly reduces the sensitivity to lubrication conditions and surface conditions, making it more reliable under heavy-load impact conditions.

[0037] Each flange connection bolt 22 is provided with an independent anti-loosening sleeve 23. The independent anti-loosening sleeve 23 includes a hexagonal sleeve body 231, a hinge pin 232, and a hinge bolt 233.

[0038] Please see Figure 4 The hexagonal sleeve 231 has an internal hexagonal hole for fitting and circumferentially restraining the nut. The dimension across the sides of the internal hexagonal hole of the hexagonal sleeve 231 is the nominal external hexagonal dimension of the nut plus 0.2mm to 0.5mm. The single-sided clearance between the hexagonal sleeve 231 and the nut is no greater than 0.3mm, ensuring easy fitting while limiting the nut's loosening angle to a very small range. The axial length of the hexagonal sleeve 231 is 5mm to 10mm greater than the thickness of the nut, completely enclosing the nut after fitting. A deflected boss is provided on the radially outer side of the hexagonal sleeve 231, with a first pin hole on the deflected boss. The hexagonal sleeve 231 is made of 40Cr or 42CrMo alloy steel, with a heat treatment hardness of HRC38 to 42, and a minimum wall thickness of not less than 8mm.

[0039] The first end of the hinge bolt 233 has a double-fork structure, with coaxial second pin holes on the two fork arms. The second end of the hinge bolt 233 has a threaded structure, passing through the corresponding structure on the rigid collar 21 and being tightened by a lock nut. The hinge bolt 233 is M12 to M20, with a performance grade not lower than 10.9, and a tightening torque of 80 N·m to 200 N·m. The hinge bolt 233 is made of 40Cr or 42CrMo alloy steel to ensure strength and toughness. The hinge pin 232 passes through the second pin hole and the first pin hole, hingedly connecting the hinge bolt 233 to the hexagonal sleeve 231. This hinged connection allows the hinge bolt 233 to swing around the hinge pin 232 within a certain angle, facilitating fine-tuning and alignment during installation. The hinge pin 232 is cylindrical, with a shoulder at one end to prevent detachment and a cotter pin hole at the other end for securing with a cotter pin after installation.

[0040] The installation of this device is divided into two stages: first, the rigid collar 21 is installed, and then the individual anti-loosening sleeves 23 are installed. When installing the rigid collar 21, each sector segment is sequentially fitted onto the outer circumference of the flange, ensuring that the bolt holes 212 on each sector segment are initially aligned with the flange bolt holes. The positions of each sector segment are adjusted so that the connecting lugs 211 of adjacent sector segments fit together. Connecting bolts are then inserted and tightened to fix each sector segment into a complete annular rigid collar 21. At this point, the annular stepped surface of the rigid collar 21 fits against the flange end face, achieving axial positioning.

[0041] The flange connecting bolts 22 are passed sequentially through the bolt holes 212 on the sector segment and the flange bolt holes. Then, nuts are screwed onto the ends of the flange connecting bolts 22 and tightened to the specified preload. At this time, the rigid collar 21 is pressed between the flange end face and the nut, achieving circumferential fixation and axial compression.

[0042] This structure utilizes the tightening force of the flange connecting bolts 22 to position and fix the rigid collar 21, eliminating the need for additional positioning holes or positioning pins. When installing each independent anti-loosening sleeve 23, the pre-assembled independent anti-loosening sleeve 23, i.e., the hexagonal sleeve 231, the hinge pin 232, and the hinge bolt 233, are already hinged together by the hinge pin 232 and moved from the outside of the rigid collar 21 toward the flange.

[0043] First, pass the hexagonal sleeve 231 through the mounting position on the rigid collar 21 and fit it onto the corresponding nut, with the inner hexagonal hole of the hexagonal sleeve 231 and the outer hexagonal hole of the nut having a clearance fit. Simultaneously, insert the threaded end of the hinge bolt 233 into the side of the hinge bolt U-shaped retainer 213 on the rigid collar 21, so that the threaded section passes through the hinge bolt U-shaped retainer 213 and extends beyond the outer side of the rigid collar 21. Adjust the position of the hexagonal sleeve 231 so that the threaded section of the hinge bolt 233 naturally aligns with the direction of the hinge bolt U-shaped retainer 213. Place a spring washer on the extended threaded section of the hinge bolt 233 and screw on the lock nut, allowing the lock nut to fall into the countersunk platform 214 of the retainer. Use a torque wrench to tighten the lock nut to the specified torque. As the lock nut is tightened, the hinge bolt 233 is pulled tight. Its double-forked end pulls the hexagonal sleeve 231 through the hinge pin 232, causing the bottom surface of the hexagonal sleeve 231 to press against the inner end face of the rigid collar 21, forming a rigid connection. After tightening, there is no relative movement between the independent anti-loosening sleeve 23 and the rigid collar 21. Repeat the above operation to complete the installation of all independent anti-loosening sleeves 23.

[0044] This anti-loosening device provides a dual locking mechanism during operation, with the two locking functions being independent and mutually redundant. The first locking is a full-circle rigid linkage. The full-circle rigid collar 21, composed of various sector-shaped segments, is axially fixed to the flange end face via an annular stepped surface and is tightened by nuts through bolt holes 212 via flange connecting bolts 22, achieving circumferential fixation. All independent anti-loosening sleeves 23 are rigidly connected to the rigid collar 21 via hinge bolts 233, forming a full-circle linkage. When any nut has a tendency to loosen and rotate, this tendency is first constrained by the inner hexagonal hole of the hexagonal sleeve 231; since the hexagonal sleeve 231 is rigidly connected to the rigid collar 21, and the rigid collar 21 forms an overall constraint with the flange and nut through the clamping force of the flange connecting bolts 22, the rotational freedom of the nut is completely restricted.

[0045] Simultaneously, due to the rigid linkage of the rigid collar 21, the loosening torque of a single nut is transmitted to all independent anti-loosening sleeves 23 through the rigid collar 21, forming a resistance network shared by the entire ring. The rigid linkage of the entire ring reduces the preload unevenness from ±25% to ±30% in the existing scheme to within ±10%. The second locking is for the independent locking of the hinge bolts. The locking nut at the end of each hinge bolt 233 independently provides an adjustable anti-loosening friction force. The locking nut is embedded in the countersunk platform 214, and the sidewall of the countersunk platform 214 forms a mechanical circumferential constraint on the locking nut, preventing the nut from loosening due to vibration. Even if the first locking fails locally due to extreme working conditions, such as an unexpected drop in the preload of a flange connection bolt, the second locking can still maintain the basic constraint of each independent anti-loosening sleeve 23. The dual locking mechanism significantly reduces the probability of anti-loosening failure. Under the extreme condition of a 50% drop in the preload of the hinge bolt, the rigid constraint of the entire ring can still limit the nut loosening angle to within 5°.

[0046] Each independent anti-loosening sleeve 23 is independently connected to the rigid collar 21 only through its corresponding hinge bolt 233, and there is no direct connection between adjacent independent anti-loosening sleeves 23. To remove an independent anti-loosening sleeve 23 for maintenance or nut replacement, simply loosen the corresponding locking nut, and laterally pull the threaded section of the hinge bolt 233 out of the U-shaped retainer 213. The hexagonal sleeve 231 can then be removed from the nut without disassembling the rigid collar 21 or other independent anti-loosening sleeves 23. The disassembly and assembly time for a single independent anti-loosening sleeve 23 does not exceed 3 minutes. To re-tighten the preload of a bolt, loosen the corresponding locking nut individually, readjust the nut preload, and then tighten the locking nut again to achieve secondary tightening. This operation does not interfere with the locking status of other independent anti-loosening sleeves 23.

[0047] The technical parameters of this invention are designed to match the actual working conditions of large universal joints used in steel pipe rolling mills. Generally, the range of technical parameters for this invention is as follows: Applicable bolt sizes: M30~M48; Applicable bolt quantity: 12-32 pieces; Applicable bolt performance grades: 10.9 and 12.9; Rigid collar (21) material: 42CrMo or 40CrNiMoA, yield strength not less than 750MPa, thickness 25mm~40mm; Number of sector segments: at least 2; Segmented connection bolts: M12~M16, grade 10.9; Hexagonal sleeve (231) material: 40Cr or 42CrMo, heat treatment hardness HRC38~42, minimum wall thickness not less than 8mm; The inner hexagonal dimension of the sleeve (231) is: the nominal outer hexagonal dimension of the nut +0.2mm to +0.5mm; The clearance between the hexagonal sleeve (231) and the nut on one side is no more than 0.3mm; Axial length of hexagonal sleeve (231): nut thickness + 5mm ~ 10mm; Hinged bolt (233) specifications: M12~M20, performance grade not lower than 10.9, tightening torque 80N·m~200N·m; Bayonet countersunk platform (214) Depth: 2mm~4mm, Diameter: Locking nut cross-side dimension + 4mm or more; Hinged bolt U-shaped bayonet (213) width: Hinged bolt (233) shank diameter + 3mm~5mm.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for preventing loosening of large shaft connecting bolts, used for preventing loosening and locking of large universal joint flange connecting bolts, wherein the flange has multiple bolt holes along the circumferential direction, and each bolt hole is provided with a flange connecting bolt (22) and fitted with a nut, characterized in that, include: Rigid collar (21), the rigid collar (21) is fitted on the outer side of the flange end face, and the rigid collar (21) has mounting positions along the circumferential direction that correspond one-to-one with the bolt holes; Multiple independent anti-loosening sleeves (23), each of the independent anti-loosening sleeves (23) is correspondingly provided with one of the flange connecting bolts (22), the independent anti-loosening sleeves (23) have a constraint structure for fitting and circumferentially constraining the nut; the independent anti-loosening sleeves (23) also include a hinge bolt (233), the first end of the hinge bolt (233) is hinged to the independent anti-loosening sleeve (23), and the second end of the hinge bolt (233) passes through the corresponding structure on the rigid collar (21) and is fastened by a lock nut; After the locking nut is tightened, the independent anti-loosening sleeve (23) and the rigid collar (21) form a rigid connection, and the independent anti-loosening sleeves (23) are linked together by the rigid collar (21).

2. The anti-loosening device for large shaft connecting bolts according to claim 1, characterized in that, The rigid collar (21) is a split-type composite collar, which is assembled from at least two fan-shaped segments connected end to end along the circumferential direction; each fan-shaped segment has connecting lugs (211) at both ends, and the connecting lugs (211) of adjacent fan-shaped segments are detachably and fixedly connected by connecting bolts passing through the collar connecting bolt holes (215); each fan-shaped segment has bolt holes (212) that correspond one-to-one with the number and position of the flange bolt holes it covers, and the flange connecting bolts (22) pass through the bolt holes (212) to press and fix the fan-shaped segments to the flange end face.

3. The anti-loosening device for large shaft connecting bolts according to claim 2, characterized in that, Each of the fan-shaped segments has a stepped structure on its inner edge end face. After the fan-shaped segments are assembled, the stepped structures together form a complete annular stepped surface. The annular stepped surface is used to fit against the flange end face to realize the axial positioning and load transfer of the rigid collar (21).

4. The anti-loosening device for large shaft connecting bolts according to claim 1, characterized in that, The rigid collar (21) has an axially penetrating U-shaped slot (213) for each mounting position, and the second end of the hinge bolt (233) is engaged or disengaged from the side of the U-shaped slot (213).

5. The anti-loosening device for large shaft connecting bolts according to claim 4, characterized in that, The hinge bolt U-shaped bayonet (213) has a recessed bayonet countersunk platform (214) at one end near the outer edge of the rigid collar (21). After the locking nut is tightened, it is at least partially embedded in the bayonet countersunk platform (214). The side wall of the bayonet countersunk platform (214) forms a circumferential constraint on the locking nut.

6. The anti-loosening device for large shaft connecting bolts according to claim 1, characterized in that, The independent anti-loosening sleeve (23) includes a hexagonal sleeve (231), a hinge pin (232), and a hinge bolt (233). The hexagonal sleeve (231) has an inner hexagonal hole for fitting and circumferentially constraining the nut. The radially outer side of the hexagonal sleeve (231) is provided with a deflecting boss, and a first pin hole is provided on the deflecting boss. The first end of the hinge bolt (233) is a double-fork structure, and a second coaxial pin hole is provided on the two fork arms of the double-fork structure. The hinge pin (232) passes through the second pin hole and the first pin hole to hinge the hinge bolt (233) to the hexagonal sleeve (231).

7. The anti-loosening device for large shaft connecting bolts according to claim 6, characterized in that, The side dimension of the inner hexagonal hole of the hexagonal sleeve (231) is the nominal outer hexagonal dimension of the nut plus 0.2mm to 0.5mm, and the single-sided fitting clearance between the hexagonal sleeve (231) and the nut is not greater than 0.3mm; the axial length of the hexagonal sleeve (231) is 5mm to 10mm greater than the thickness of the nut.

8. The anti-loosening device for large shaft connecting bolts according to claim 6, characterized in that, The axial length of the hexagonal sleeve (231) is 8 mm greater than the thickness of the nut.

9. The anti-loosening device for large shaft connecting bolts according to claim 1, characterized in that, Each of the independent anti-loosening sleeves (23) is independently connected to the rigid collar (21) only through its corresponding hinge bolt (233), and there is no direct connection between adjacent independent anti-loosening sleeves (23); when disassembling any independent anti-loosening sleeve (23), it is only necessary to loosen the corresponding locking nut to remove the independent anti-loosening sleeve (23) from the corresponding nut.

10. The anti-loosening device for large shaft connecting bolts according to claim 1, characterized in that, The rigid collar (21) is made of alloy steel with a yield strength of not less than 750MPa, and the thickness of the rigid collar (21) is 25mm to 40mm; the hinge bolt (233) has a specification of M12 to M20 and a performance grade of not less than 10.9, and the tightening torque of the hinge bolt (233) is 80N·m to 200N·m; the hexagonal sleeve (231) is made of 40Cr or 42CrMo alloy steel, and the heat treatment hardness is HRC38 to 42, and the minimum wall thickness of the hexagonal sleeve (231) is not less than 8mm; the anti-loosening device is suitable for large shaft flange connections with bolt specifications of M30 to M48 and a number of bolts of 12 to 32.

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