Limit bolt fastening machine

Abstract

The invention discloses a bolt limit fastening machine which comprises a hydraulic stretcher assembly (100) used for applying axial stretching force to a bolt; a hydraulic wrench assembly (200) for applying torque to the nut; wherein the hydraulic tensioner assembly (100) and the hydraulic wrench assembly (200) are coaxially sleeved and integrally arranged, and the hydraulic tensioner assembly (100) and the hydraulic wrench assembly (200) can cooperatively apply pre-tightening force to a bolt. According to the bolt limit fastening machine, organic fusion of two fastening modes can be achieved, high and consistent residual pre-tightening force can be obtained after a bolt is tightened, and the defects of a traditional torque method and a traditional stretching method are overcome. The invention further provides a bolt limit fastening method. The bolt limit fastening machine and the bolt limit fastening method are wide in application range and have good economic value.

Description

Technical Field

[0001] This invention relates generally to the field of bolt fastener technology, and more specifically to a bolt limit tightening machine that combines the functions of a hydraulic wrench and a hydraulic tensioner. Background Technology

[0002] In fields such as large machinery, pressure vessels, wind turbines, and chemical pipelines, the quality of bolt tightening directly affects the safety and reliability of the overall structure. There are two main common bolt tightening methods: 1. Torque Method: This method involves applying torque to the bolt using tools such as hydraulic wrenches to create a preload. A hydraulic wrench, short for hydraulic torque wrench, is a specialized bolt tightening tool that uses hydraulic power to provide high torque output for installing and loosening bolts, often used to tighten and loosen larger bolts. Currently, Chinese Patent Publication No. CN221160155U discloses a thin hydraulic wrench. However, due to the significant influence of friction, the preload of this device is unstable and has a large dispersion, making it difficult to guarantee the preload accuracy of bolt groups.

[0003] 2. Tensioning method: This method involves applying axial tension directly to the bolt using a hydraulic tensioner, causing the bolt to elongate and then tighten. In the prior art, Chinese Patent Publication No. CN220029319U discloses a bolt hydraulic tensioner. During use, after the tensioner is depressurized, the preload on the bolt decreases significantly, leading to a large dispersion in the preload of individual bolts in the bolt group.

[0004] The aforementioned technologies each have their drawbacks, and this invention arose precisely in this context. Summary of the Invention

[0005] To overcome the above shortcomings, the present invention provides a bolt limit tightening machine. This device combines a hydraulic wrench and a hydraulic tensioner, thereby enabling the simultaneous application of axial tensile force and torque on the same bolt axis, thus combining the advantages of both tightening methods and avoiding their respective defects.

[0006] In this invention, a hydraulic tensioner assembly is used to apply an axial tensile force to the bolt, causing the bolt to elongate elastically; while the bolt is in a tensile state, a hydraulic wrench assembly applies torque to the nut to tighten it; subsequently, the tensile force of the hydraulic tensioner assembly is released, and the bolt retains residual preload.

[0007] Through the above operations, the hydraulic wrench assembly and the hydraulic tensioner assembly work together on the same axis, or in other words, act on the same bolt on the same axis, effectively avoiding off-center loading and improving force transmission efficiency and bolt preload consistency. Compared with using the torque method or tension method alone, this invention can significantly improve tightening accuracy and reliability.

[0008] Specifically, the present invention provides a bolt limit tightening machine, which may include: a hydraulic tensioner assembly for applying axial tensile force to the bolt; and a hydraulic wrench assembly for applying torque to the nut; wherein the hydraulic tensioner assembly and the hydraulic wrench assembly are coaxially sleeved and integrated to collaboratively apply preload to the bolt.

[0009] Preferably, the hydraulic tensioner assembly may include a hydraulic tensioner assembly body, and the hydraulic wrench assembly includes a hydraulic wrench assembly body, wherein the hydraulic tensioner assembly body and the hydraulic wrench assembly body are coaxially stacked in structure.

[0010] Preferably, the hydraulic wrench assembly may include a hydraulic wrench rotary joint, which is connected to the main body of the hydraulic wrench assembly to drive the hydraulic wrench drive sleeve to rotate the nut.

[0011] Preferably, the hydraulic tensioner assembly body may include a first hollow cavity, and the hydraulic wrench assembly body may include a second hollow cavity, wherein the central axis of the first hollow cavity coincides with the central axis of the second hollow cavity.

[0012] Preferably, the hydraulic wrench assembly can apply preload using the torque method, and the hydraulic tensioner assembly can apply preload using the tension method.

[0013] Preferably, the inner hole of the hydraulic wrench drive sleeve has a polygonal structure, which is used to cooperate with the nut to transmit torque.

[0014] Preferably, the hydraulic tensioner assembly may include a hydraulic tensioner top cover, a tensioner rod return disc spring, a tensioner rod locking nut, an upper piston, an upper cylinder, a lower piston, a lower cylinder, a rod anti-fly sleeve, and a tensioner rod connected coaxially in sequence to form a first hollow cavity.

[0015] Preferably, the hydraulic wrench assembly may include a hydraulic wrench upper cover, a hydraulic wrench ratchet drive shaft, a hydraulic wrench drive sleeve, and a hydraulic wrench lower housing, which are sequentially and coaxially connected to form a second hollow cavity.

[0016] Preferably, the main body of the hydraulic wrench assembly may further include an arm consisting of a hydraulic wrench rotary joint, a rotary joint column, a hydraulic wrench cylinder, a hydraulic wrench piston, and a hydraulic wrench drive block connected coaxially in sequence, and the arm is connected to the hydraulic wrench drive sleeve by a hydraulic wrench drive connecting pin.

[0017] The present invention also provides a bolt ultimate tightening method, which may include the following steps: applying an axial tensile force to the bolt by means of a hydraulic tensioner assembly; applying torque to the nut by means of the hydraulic wrench assembly to tighten the nut while the bolt is stretched; and then releasing the hydraulic tensioner assembly to allow the bolt to retain residual preload.

[0018] Through the above technical solution, the present invention achieves the organic integration of hydraulic tension fastening and hydraulic torque fastening, which avoids the problem of preload dispersion caused by friction coefficient fluctuation when relying solely on torque fastening, and overcomes the risk of insufficient bolt preload and nut loosening when relying solely on tension fastening, thereby ensuring high precision, high reliability and high efficiency of bolt fastening.

[0019] The bolt limit tightening machine of the present invention is particularly suitable for high-strength bolt connections in wind turbine towers, pressure vessels, bridge structures, chemical pipelines and heavy machinery, and has the advantages of high pre-tightening force accuracy, simple operation and wide applicability. Attached Figure Description

[0020] This disclosure will be more fully understood from the detailed description and accompanying drawings, in which: Figure 1 This is an isometric view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 2 This is an exploded view of the equiaxial portion of a bolt limit tightening machine according to an embodiment of the present invention; Figure 3 This is an isometric exploded view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 4 This is a front view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 5 This is a rear view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 6 This is a left view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 7 This is a right view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 8 This is a top view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 9 This is a bottom view of a bolt limit tightening machine according to an embodiment of the present invention; Figure 10 This is a three-dimensional schematic diagram of a bolt limit tightening machine according to an embodiment of the present invention; Figure 11 This is a cross-sectional schematic diagram of the hydraulic tensioner assembly of a bolt limit fastening machine according to an embodiment of the present invention. Figures 12a-12c This is a cross-sectional schematic diagram of the hydraulic wrench assembly of a bolt limit tightening machine according to an embodiment of the present invention; Figure 13 This is a three-dimensional schematic diagram of a bolt limit tightening machine according to an embodiment of the present invention. Detailed Implementation

[0021] The invention will now be described in detail with reference to preferred embodiments illustrated in the accompanying drawings. In the following description, several specific details are set forth to provide a full understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without some or all of these specific details. In other instances, well-known techniques have not been described in detail to avoid unnecessarily obscuring the invention.

[0022] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of protection of the present invention.

[0023] The term "overlapping" as used in this application refers to the fact that the hydraulic wrench assembly and the hydraulic tensioner assembly are structurally coaxially connected and arranged as a single unit.

[0024] The term "integrated arrangement" as used in this application refers to the fact that the hydraulic wrench assembly and the hydraulic tensioner assembly are connected by a coaxial sleeve in terms of structure, and the two form an integrated structure as a whole.

[0025] In this application, the term "shaft" has different meanings in different contexts: when used in the name of a component, such as "ratchet drive shaft", it refers to a specific shaft-shaped component; when used in geometric relationships, such as "bolt shaft", "center shaft", etc., it refers to the axis, and "coaxial" or "shared axis" means that the axes of related components coincide or substantially coincide, that is, the geometric center lines and / or rotation axes of these components coincide or substantially coincide.

[0026] In an embodiment of the present invention, both the hydraulic tensioner assembly body and the hydraulic wrench assembly body have hollow cavities, preferably hollow cylindrical cavities. The hollow cavity of the hydraulic tensioner assembly body coincides with the axis of the bolt to be tightened, and the hollow cavity of the drive sleeve or ratchet drive shaft of the hydraulic wrench assembly body also coincides with the axis of the bolt. Through the above-mentioned overlapping connection structure, the axial tensile force applied by the hydraulic tensioner assembly and the torque applied by the hydraulic wrench assembly act on the same bolt on the same axis, thereby avoiding the off-center load phenomenon that is prone to occur during the use of traditional split tools. This structure not only improves the force transmission efficiency, but also significantly improves the consistency of bolt preload, ensuring that a high and consistent residual preload can be obtained under high-intensity working conditions, avoiding the defects of traditional torque and tension methods.

[0027] like Figures 1 to 3 As shown, the bolt ultimate tightening machine of the present invention includes a hydraulic tensioner assembly 100 and a hydraulic wrench assembly 200. The two are connected and integrated in a coaxial manner to achieve coordinated operation. The hydraulic tensioner assembly 100 applies axial tensile force to the bolt, causing it to elastically elongate; the hydraulic wrench assembly 200 applies torque to the nut and tightens it. Because the two work together on the same axis, the nut can be tightened smoothly while the bolt is under tension, thereby reducing the impact of frictional fluctuations.

[0028] like Figure 1 and Figure 2 As shown, the bolt limit tightening machine 300 includes: a hydraulic tensioner assembly 100 for applying axial tensile force to the bolt; and a hydraulic wrench assembly 200 for applying torque to the nut. The hydraulic tensioner assembly 100 includes a hydraulic tensioner assembly body 101 and a tensioner diverter block 8, which is side-connected to the hydraulic tensioner assembly body 101.

[0029] The hydraulic wrench assembly 200 includes a hydraulic wrench assembly body 202 and a hydraulic wrench rotary joint 17. The hydraulic wrench rotary joint 17 is connected to one end of the hydraulic wrench assembly body 202, and the other end of the hydraulic wrench assembly body 202 is connected to the hydraulic tensioner assembly body 101.

[0030] like Figure 3 As shown, the main body 101 of the hydraulic tensioner assembly includes the following components: hydraulic tensioner top cover 1, tensioner rod return disc spring 2, tensioner rod locking nut 3, tensioner upper piston 4, tensioner upper cylinder 5, tensioner lower piston 6, tensioner lower cylinder 7, rod anti-fly sleeve 9, and tensioner rod 10. These components are coaxially connected in the order shown to form a first hollow cavity. The tensioner diverter block 8 is attached to the outer surface of the tensioner lower piston 6 and the tensioner lower cylinder 7, and has a channel that is in fluid communication with the first hollow cavity.

[0031] The hydraulic wrench assembly body 202 includes: a hydraulic wrench upper cover 11, a hydraulic wrench ratchet drive shaft 12, a hydraulic wrench pawl 13, a hydraulic wrench pawl 14, a hydraulic wrench drive sleeve 15, a hydraulic wrench drive connecting pin 16, a rotary joint column 18, a hydraulic wrench cylinder 19, a hydraulic wrench piston 20, a hydraulic wrench drive block 21, a hydraulic wrench drive check pin 22, and a hydraulic wrench lower housing 23. The hydraulic wrench upper cover 11, the hydraulic wrench ratchet drive shaft 12, the hydraulic wrench drive sleeve 15, and the hydraulic wrench lower housing 23 each have a hollow portion, and these hollow portions are coaxially connected in the indicated order to form a second hollow cavity. The first hollow cavity and the second hollow cavity are coaxial. The hydraulic wrench rotary joint 17, the rotary joint column 18, the hydraulic wrench cylinder 19, the hydraulic wrench piston 20, and the hydraulic wrench drive block 21 are coaxially connected in sequence. The hydraulic wrench drive sleeve 15 has a flange. The hydraulic wrench drive block 21 is laterally connected to the hydraulic wrench drive sleeve 15 via the hydraulic wrench drive connecting pin 16 and the flange, and is located on the same side as the tensioner diverter block 8. A portion of the hydraulic wrench ratchet drive shaft 12, the hydraulic wrench pawl 13, and the hydraulic wrench pawl 14 are located within the hydraulic wrench drive sleeve 15. The hydraulic wrench upper cover 11 and the hydraulic wrench lower housing 23 are joined to form a hollow chamber that accommodates the hydraulic wrench drive sleeve 15, the hydraulic wrench drive connecting pin 16, the hydraulic wrench piston 20, and the hydraulic wrench drive block 21. The hydraulic wrench drive check pin 22 is fixed to the hydraulic wrench lower housing 23.

[0032] The arm of the hydraulic wrench assembly 202 is composed of a hydraulic wrench rotary joint 17, a rotary joint column 18, a hydraulic wrench cylinder 19, a hydraulic wrench piston 20, and a hydraulic wrench drive block 21, all connected coaxially in sequence. Under hydraulic pressure, the hydraulic wrench cylinder 19 and the hydraulic wrench piston 20 drive the hydraulic wrench drive block 21 to reciprocate, and transmit power to the hydraulic wrench drive sleeve 15 through the hydraulic wrench drive connecting pin 16, thereby achieving torque output to the nut. This arm structure, while ensuring the coaxial arrangement of the hydraulic wrench assembly 200 and the hydraulic tensioner assembly 100, effectively improves the efficiency and reliability of torque transmission and makes the overall structure more compact.

[0033] The hydraulic wrench assembly 200 includes a drive sleeve 15. The drive sleeve 15 has a polygonal inner hole structure, preferably hexagonal, for mating with a nut to transmit torque. The hydraulic tensioner assembly 100 and the hydraulic wrench assembly 200 are structurally coaxially arranged such that the axial tensile force applied to the bolt by the hydraulic tensioner assembly 100 and the torque applied by the hydraulic wrench assembly 200 through the drive sleeve 15 act on the same axis, thereby further avoiding off-center loading.

[0034] During operation, the hydraulic tensioner assembly 100 first applies an axial tensile force to the bolt, causing it to elongate. In this state, the hydraulic wrench assembly 200 applies torque to the nut, tightening it. Subsequently, the tension force of the hydraulic tensioner assembly 100 is released, and the bolt retains the required residual preload.

[0035] Through the above structure and operation, the bolt limit tightening machine of the present invention can combine the advantages of torque method and tension method, which not only reduces the instability of preload caused by friction coefficient fluctuation, but also avoids the problem of insufficient preload after pressure relief by simply relying on tension method, thereby significantly improving the accuracy and reliability of bolt tightening.

[0036] The bolt limit tightening machine of the present invention is particularly suitable for large-specification, high-strength bolt connections in wind turbine towers, pressure vessels, bridge structures, and heavy machinery, and has the advantages of high pre-tightening force accuracy, simple operation, and wide applicability.

[0037] Although preferred embodiments of the invention have been described exemplary with reference to the accompanying drawings, it should be understood that the invention is not limited to these preferred embodiments. Many modifications, alterations, and other equivalents can be made by those skilled in the art based on this invention, all of which fall within the scope of this invention.

Claims

1. A bolt limit tightening machine, characterized in that, include: A hydraulic tensioner assembly (100) for applying axial tensile force to a bolt; A hydraulic wrench assembly (200) for applying torque to a nut; The hydraulic tensioner assembly (100) and the hydraulic wrench assembly (200) are coaxially connected and integrated to work together to apply preload to the bolt.

2. The bolt limit tightening machine according to claim 1, characterized in that, The hydraulic tensioner assembly (100) includes a hydraulic tensioner assembly body (101), and the hydraulic wrench assembly (200) includes a hydraulic wrench assembly body (202). The hydraulic tensioner assembly body (101) and the hydraulic wrench assembly body (202) are coaxially stacked in structure.

3. The bolt limit tightening machine according to claim 1 or 2, characterized in that, The hydraulic wrench assembly (200) includes a hydraulic wrench rotary joint (17), which is connected to the hydraulic wrench assembly body (202) to drive the hydraulic wrench drive sleeve (15) to rotate the nut.

4. The bolt limit tightening machine according to claim 3, characterized in that, The hydraulic tensioner assembly body (101) includes a first hollow cavity, and the hydraulic wrench assembly body (202) includes a second hollow cavity, wherein the central axis of the first hollow cavity coincides with the central axis of the second hollow cavity.

5. The bolt limit tightening machine according to claim 3, characterized in that, The hydraulic wrench assembly (200) applies preload using the torque method, and the hydraulic tensioner assembly (100) applies preload using the tension method.

6. The bolt limit tightening machine according to claim 3, characterized in that, The inner hole of the hydraulic wrench drive sleeve (15) has a polygonal structure, which is used to cooperate with the nut to transmit torque.

7. The bolt limit tightening machine according to claim 1, characterized in that, The hydraulic tensioner assembly (100) includes a hydraulic tensioner top cover (1), a tensioner rod return disc spring (2), a tensioner rod locking nut (3), a tensioner upper piston (4), a tensioner upper cylinder (5), a tensioner lower piston (6), a tensioner lower cylinder (7), a rod anti-fly sleeve (9), and a tensioner rod (10) that are sequentially coaxially connected to form a first hollow cavity.

8. The bolt limit tightening machine according to claim 7, characterized in that, The hydraulic wrench assembly (200) includes a hydraulic wrench upper cover (11), a hydraulic wrench ratchet drive shaft (12), a hydraulic wrench drive sleeve (15), and a hydraulic wrench lower housing (23) that are sequentially and coaxially connected to form a second hollow cavity.

9. The bolt limit tightening machine according to claim 8, characterized in that, The main body (202) of the hydraulic wrench assembly also includes an arm consisting of a hydraulic wrench rotary joint (17), a rotary joint column (18), a hydraulic wrench cylinder (19), a hydraulic wrench piston (20), and a hydraulic wrench drive block (21) connected coaxially in sequence. The arm is connected to the hydraulic wrench drive sleeve (15) by a hydraulic wrench drive connecting pin (16).

10. A method for ultimate bolt tightening, characterized in that, Includes the following steps: An axial tensile force is applied to the bolt by a hydraulic tensioner assembly (100); With the bolt stretched, the hydraulic wrench assembly (200) is used to apply torque to the nut to tighten it; The hydraulic tensioner assembly (100) is then released to allow the bolt to retain residual preload.

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