Double-acting integrated hydraulic nut and hydraulic nut system

Abstract

The invention discloses a double-acting integrated hydraulic nut and a hydraulic nut system. The double-acting integrated hydraulic nut comprises a cylinder body, a piston, a cylinder cover, a locking nut, an outer hexagon head bolt and a locking sleeve. A mounting plane attached to a workpiece is arranged at the bottom of the cylinder body, and the piston is arranged in an inner cavity of the cylinder body in an axial sliding mode. The outer hexagonal head bolt sequentially penetrates through the axial through hole of the piston and the bottom of the cylinder body, and the threaded end of the outer hexagonal head bolt is meshed with a workpiece in a threaded mode. The cylinder cover is arranged at the top of the cylinder body; the locking nut is in threaded connection with the piston rod and is in contact with the top surface of the cylinder cover; a pressurizing oil port connected with a hydraulic pump station is formed in the side wall of the cylinder body. The hexagonal head of the outer hexagonal head bolt is sleeved with the locking sleeve which is in driving connection with the electric wrench. Due to the fact that the bearing seat bolts are compact in layout and large in bolt pre-tightening force requirement, the experiment platform can be rapidly mounted and dismounted, and working time and cost are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic nuts, and in particular to a double-acting integrated hydraulic nut and a hydraulic nut system. Background Art

[0002] Currently, large-scale wind turbine bearing seat loading test platforms mostly use single-cylinder hydraulic nuts for bolt tightening, but this has significant drawbacks under high preload and compact layout conditions. The single-cylinder structure has insufficient output to meet the large preload requirements, and the need for multiple additional cylinders leads to bloated equipment and large space requirements. The cylinder position must be repeatedly adjusted during assembly and disassembly, which is cumbersome and time-consuming. In addition, traditional hydraulic nuts rely on manual tightening of the lock nut, resulting in poor preload consistency, which can easily cause bolt loosening or overload failures, affecting experimental accuracy and equipment reliability.

[0003] In existing technologies, hydraulic nuts generally adopt a split design, separating the oil cylinder from the locking mechanism. This results in a loose overall structure that cannot adapt to the densely arranged bolt holes in the fan bearing seat. During frequent disassembly and assembly experiments, the traditional hydraulic system's pressure control accuracy is insufficient, making it difficult to achieve precise regulation of axial force, and the operation and maintenance costs remain high. To address these issues, there is an urgent need for a hydraulic nut with high integration, high output, and easy and precise control to meet the dual needs of efficient disassembly and assembly and high preload loading in a compact layout. Summary of the Invention

[0004] In response to the above technical problems in the related art, the present invention proposes a double-acting integrated hydraulic nut and a hydraulic nut system, which can overcome the above shortcomings of the prior art.

[0005] To achieve the above technical objectives, the technical solution of the present invention is implemented as follows: In a first aspect, the present invention provides a double-acting integrated hydraulic nut; The double-acting integrated hydraulic nut includes a cylinder body, a piston, a cylinder head, a locking nut, an external hexagonal head bolt and a locking sleeve; the bottom of the cylinder body is provided with a mounting plane that fits the workpiece, and the piston is axially slidably arranged in the inner cavity of the cylinder body; the external hexagonal head bolt passes through the axial through hole of the piston and the bottom of the cylinder body in sequence, and the threaded end of the external hexagonal head bolt is engaged with the thread of the workpiece; the cylinder head is arranged on the top of the cylinder body, and the locking nut is threadedly connected to the rod of the piston and contacts the top surface of the cylinder head; the side wall of the cylinder body is provided with a pressurized oil port connected to the double-acting stretching hydraulic pump station, and the locking sleeve is sleeved on the hexagonal head of the external hexagonal head bolt and is connected to the electric wrench drive.

[0006] Furthermore, an axial positioning structure is provided between the locking sleeve and the bottom surface of the cylinder body, and the inner hole of the locking sleeve is provided with a hexagonal cavity that forms an anti-rotation fit with the head of the external hexagonal head bolt.

[0007] Furthermore, a seal is provided between the piston and the cylinder body, and the seal is arranged between the outer peripheral wall of the piston and the inner wall of the cylinder body.

[0008] Furthermore, the pressurized oil port of the cylinder body is connected to a double-acting stretching hydraulic pump station through a quick-change joint, and the pressure control system of the double-acting stretching hydraulic pump station includes a proportional relief valve and a digital pressure sensor.

[0009] Furthermore, the inner hole of the locking sleeve is provided with a hexagonal cavity which cooperates with the bolt head to prevent rotation, and an axial positioning structure is provided between the locking sleeve and the bottom surface of the cylinder body.

[0010] Furthermore, the inner contour of the locking sleeve matches the outer hexagonal contour of the locking nut, and the electric wrench transmits torque to the locking nut by driving the locking sleeve to rotate.

[0011] Furthermore, the working area of ​​the piston of the cylinder body is 7000-7100 mm², the maximum working pressure of the hydraulic system is 200 MPa, and the effective stroke of the piston is 15-25 mm.

[0012] In a second aspect, the present invention provides a hydraulic nut system; The hydraulic nut system includes the above-mentioned double-acting integrated hydraulic nut and double-acting stretching hydraulic pump station, the hydraulic pump station is connected to the pressurized oil port of the cylinder body through a quick-change joint; the pressure control system of the hydraulic pump station includes a proportional relief valve and a digital pressure sensor; the hydraulic pump station is configured to supply oil to the hydraulic oil chamber in both directions to control the extension and retraction of the piston.

[0013] Furthermore, the double-acting stretching hydraulic pump station includes an electro-hydraulic proportional reversing valve and a high-pressure accumulator; the electro-hydraulic proportional reversing valve is controlled in linkage with the proportional relief valve to achieve stepless adjustment of the piston extension / retraction speed; the high-pressure accumulator is connected to the oil outlet pipeline of the pump station to stabilize the system pressure fluctuations.

[0014] Furthermore, the oil circuit system of the hydraulic pump station adopts a parallel dual oil circuit design, in which the first oil circuit is connected to the pressurized oil chamber to control the extension of the piston, and the second oil circuit is connected to the retraction oil chamber to control the retraction of the piston; both oil circuits are equipped with independent pressure sensors and safety relief valves.

[0015] The beneficial effects of the present invention are as follows: through the structural optimization and improvement design of the double-acting integrated hydraulic nut, the integrated cylinder body and double-acting oil chamber layout are adopted to effectively reduce the axial installation space, break through the traditional single-cylinder output bottleneck, and realize precise regulation of the preload force; the synchronous displacement mechanism of the piston-linked tensioning bolt is combined with the hydraulic pressure linear control to ensure the consistency of the axial loading force and reduce the risk of equipment overload; the fast disassembly and assembly of the locking sleeve and the electric wrench further improves the efficiency of the disassembly and assembly of the bolt group of the experimental platform, and greatly reduces the overall working time and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a front view of the overall structure of a double-acting integrated hydraulic nut according to an embodiment of the present invention; Figure 2 This is a top view of the overall structure of a double-acting integrated hydraulic nut according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the locking principle of a double-acting integrated hydraulic nut in a high-pressure oil-inlet state according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the locking principle of an electric wrench locking nut for a double-acting integrated hydraulic nut according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the principle of loosening a double-acting integrated hydraulic nut in a high-pressure oil-inlet state according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the loosening principle of a nut using an electric wrench for a double-acting integrated hydraulic nut according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the principle of loosening a double-acting integrated hydraulic nut in a piston reset state according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the installation of a double-acting integrated hydraulic nut according to an embodiment of the present invention applied to a fan bearing seat; In the figure: 1. Cylinder body; 2. Piston; 3. Cylinder head; 4. Locking nut; 5. Hexagon head bolt; 6. Locking sleeve; 7. Electric wrench. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] It should be understood that in the description of the embodiments of the present invention, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the embodiments of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0020] like Figure 1-6 As shown, a double-acting integrated hydraulic nut according to an embodiment of the present invention includes a cylinder body 1, a piston 2, a cylinder head 3, a locking nut 4, an external hexagonal head bolt 5 and a locking sleeve 6; the bottom of the cylinder body 1 is provided with a mounting plane that fits the workpiece, and the piston 2 can be axially slidably arranged in the inner cavity of the cylinder body 1; the external hexagonal head bolt 5 passes through the axial through hole of the piston 2 and the bottom of the cylinder body 1 in sequence, and the threaded end of the external hexagonal head bolt 5 is engaged with the workpiece thread; the cylinder head 3 is arranged at the top of the cylinder body 1, and the locking nut 4 is threadedly connected to the rod of the piston 2 and contacts the top surface of the cylinder head 3; the side wall of the cylinder body 1 is provided with a pressurized oil port connected to the double-acting stretching hydraulic pump station, and the locking sleeve 6 is sleeved on the hexagonal head of the external hexagonal head bolt 5 and is driven and connected to the electric wrench 7.

[0021] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, an axial positioning structure is provided between the locking sleeve 6 and the bottom surface of the cylinder body 1, and the inner hole of the locking sleeve 6 is provided with a hexagonal cavity that forms an anti-rotation fit with the head of the external hexagon head bolt 5.

[0022] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, a seal is provided between the piston 2 and the cylinder body 1 , and the seal is arranged between the outer peripheral wall of the piston 2 and the inner wall of the cylinder body 1 .

[0023] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, the pressurized oil port of the cylinder body 1 is connected to the double-acting stretching hydraulic pump station through a quick-change connector, and the pressure control system of the double-acting stretching hydraulic pump station includes a proportional relief valve and a digital pressure sensor.

[0024] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, the inner hole of the locking sleeve 6 is provided with a hexagonal cavity that cooperates with the bolt head to prevent rotation, and an axial positioning structure is provided between the locking sleeve 6 and the bottom surface of the cylinder body 1.

[0025] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, the inner contour of the locking sleeve 6 matches the outer hexagonal contour of the locking nut 4, and the electric wrench 7 drives the locking sleeve 6 to rotate to transmit torque to the locking nut 4.

[0026] According to a double-acting integrated hydraulic nut described in an embodiment of the present invention, in a specific embodiment, the piston working area of ​​the cylinder body 1 is 7000-7100 mm², the maximum working pressure of the hydraulic system is 200 MPa, and the effective stroke of the piston 2 is 15-25 mm.

[0027] In addition, if Figure 7 As shown, the hydraulic nut system described in the present invention includes the above-mentioned double-acting integrated hydraulic nut and double-acting stretching hydraulic pump station, and the hydraulic pump station is connected to the pressurized oil port of the cylinder body 1 through a quick-change joint; the pressure control system of the hydraulic pump station includes a proportional relief valve and a digital pressure sensor; the hydraulic pump station is configured to supply oil to the hydraulic oil chamber in both directions to control the extension and retraction of the piston 2.

[0028] According to a hydraulic nut system described in an embodiment of the present invention, in a specific embodiment, the double-acting stretching hydraulic pump station includes an electro-hydraulic proportional reversing valve and a high-pressure accumulator; the electro-hydraulic proportional reversing valve and the proportional relief valve are controlled in linkage to achieve stepless adjustment of the extension / retraction speed of the piston 2; the high-pressure accumulator is connected to the oil outlet pipeline of the pump station to stabilize the system pressure fluctuations.

[0029] According to a hydraulic nut system described in an embodiment of the present invention, in a specific embodiment, the oil circuit system of the hydraulic pump station adopts a parallel dual oil circuit design, wherein the first oil circuit is connected to the pressurized oil chamber to control the extension of the piston 2, and the second oil circuit is connected to the retraction oil chamber to control the retraction of the piston 2; both oil circuits are provided with independent pressure sensors and safety pressure relief valves.

[0030] In order to facilitate understanding of the above technical solutions of the present invention, the above technical solutions of the present invention are described in detail below through specific usage methods.

[0031] According to the double-acting integrated hydraulic nut described in the present invention, the hydraulic cylinder is composed of a cylinder body 1, a piston 2, a cylinder head 3, a seal, and a locking nut 4. The bottom surface of the cylinder is in contact with the workpiece, and the external hexagonal head bolt 5 passes through the piston 2 and engages with the workpiece thread. The external hexagonal head bolt 5 can move synchronously with the piston 2. After hydraulic oil is added from the filling port, the piston 2 and the external hexagonal head bolt 5 are forced to move outward and upward, and at the same time, the workpiece is tightened. When the pulling force reaches the requirement, the locking nut 4 is tightened to relieve the pressure.

[0032] The matching double-acting stretching hydraulic pump station, with its mature technical system, ensures stable operation of the system, is not prone to failure, and can be quickly disassembled and assembled. Moreover, thanks to its simple design and mature technology, daily maintenance does not require complicated procedures and is easy to use.

[0033] The technical solution of the present invention is specifically implemented as follows: 1. Place the bottom of the hydraulic cylinder on the bolt hole of the bearing seat.

[0034] 2. Select the hexagonal head bolt 5 as the tension screw, pass it through the inner hole of the piston 2, align it with the threaded hole of the workpiece and tighten it.

[0035] 3. After all stretching screws are tightened, do not connect the oil pipes for the time being and set the pressure value of the stretching pump station.

[0036] 4. After completing the preparation work, use the oil pipe to connect the hydraulic pump station and the integrated tooling to perform the stretching operation.

[0037] 5. When the hydraulic oil from the pump station is injected into the hydraulic cylinder, the piston 2 pushes the stretching screw outward under the action of the hydraulic oil, and the workpiece is compressed by the pressure.

[0038] 6. When the pulling force reaches the requirement, use the electric wrench 7 to lock the lock nut 4 to release the pressure.

[0039] Specifically, when in use, first fit the mounting plane of the bottom of the hydraulic nut cylinder body to the bolt hole position of the bearing seat, select the hexagonal head bolt to pass through the axial through hole of the piston and the bottom of the cylinder body in turn, screw it into the threaded hole of the workpiece and tighten it preliminarily.

[0040] The double-acting tensioning hydraulic pump station is then connected to the pressurized oil port on the cylinder side wall via a quick-change connector, and the target value of the pump station's pressure control system is set (precisely controlled by a proportional relief valve and a digital pressure sensor). After the pump station is started, hydraulic oil is injected into the pressurized oil chamber through the first oil circuit, pushing the piston to slide axially upward along the cylinder cavity. At the same time, it drives the hexagonal bolt running through it to move outward synchronously, causing the bolt to generate axial tension and compress the workpiece. When the digital pressure sensor detects that the preload force has reached the set value, the operator immediately activates the electric wrench, which rotates the locking sleeve mounted on the hexagonal head of the bolt. The inner contour of the sleeve engages the outer hexagonal contour of the lock nut, thereby transmitting torque to the lock nut, tightening it against the top surface of the piston. Finally, the oil pressure is released to complete the installation.

[0041] During disassembly, the pump station supplies oil to the retraction oil chamber through the second oil circuit to drive the piston downward to reset. At the same time, the pre-tightening force can be released by loosening the locking nut with an electric wrench.

[0042] Its operating principle is a combination of double-acting hydraulic linkage and mechanical locking. The hydraulic system achieves bidirectional control through a parallel dual-circuit design. When oil is fed through the pressurized circuit, the piston, under hydraulic thrust (maximum 200 MPa acting on a piston area of ​​7000-7100 mm²), overcomes the bolt's resistance and moves upward, precisely stretching the bolt to generate a preset axial preload. At this point, the locking sleeve and the hexagonal cavity in the bolt head provide a non-rotating anti-rotation fit, preventing the bolt from rotating, while a seal between the piston and cylinder maintains a hydraulic seal. Once the preload is established, an electric wrench quickly and mechanized tightening of the locknut is achieved by matching the sleeve and nut profiles, converting the tensile displacement into a mechanical locking force. Recoil in the retraction circuit drives the piston in the opposite direction to reset. The pump station's electro-hydraulic proportional directional valve and proportional relief valve are linked to achieve stepless piston speed adjustment. A high-pressure accumulator suppresses pressure fluctuations, and independent safety relief valves in the dual circuits ensure system safety. Ultimately, this achieves integrated control for precise loading of high preload and efficient assembly and disassembly.

[0043] To sum up, with the help of the above technical scheme of the present invention, through the structural optimization and improvement design of the double-acting integrated hydraulic nut, the integrated cylinder body and double-acting oil chamber layout are adopted to effectively reduce the axial installation space, break through the traditional single-cylinder output bottleneck, and realize precise control of the preload force; the synchronous displacement mechanism of the piston-linked tensioning bolt is combined with the hydraulic pressure linear control to ensure the consistency of the axial loading force and reduce the risk of equipment overload; the fast disassembly and assembly of the locking sleeve and the electric wrench further improves the disassembly and assembly efficiency of the experimental platform bolt group, and greatly reduces the overall working time and cost.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A double-acting integrated hydraulic nut, characterized in that: The invention comprises a cylinder body (1), a piston (2), a cylinder cover (3), a locking nut (4), an external hexagonal head bolt (5) and a locking sleeve (6); the bottom of the cylinder body (1) is provided with a mounting plane that fits with a workpiece, and the piston (2) is axially slidably arranged in the inner cavity of the cylinder body (1); the external hexagonal head bolt (5) passes through the axial through hole of the piston (2) and the bottom of the cylinder body (1) in sequence, and the threaded end of the external hexagonal head bolt (5) is engaged with the thread of the workpiece; the cylinder cover (3) is arranged on the top of the cylinder body (1), and the locking nut (4) is threadedly connected to the rod of the piston (2) and contacts the top surface of the cylinder cover (3); the side wall of the cylinder body (1) is provided with a pressurized oil port connected to a double-acting stretching hydraulic pump station, and the locking sleeve (6) is sleeved on the hexagonal head of the external hexagonal head bolt (5) and is driven by an electric wrench (7).

2. A double-acting integrated hydraulic nut according to claim 1, characterized in that: An axial positioning structure is provided between the locking sleeve (6) and the bottom surface of the cylinder body (1), and the inner hole of the locking sleeve (6) is provided with a hexagonal cavity that forms an anti-rotation fit with the head of the external hexagonal head bolt (5).

3. The double-acting integrated hydraulic nut according to claim 1, characterized in that: A sealing member is provided between the piston (2) and the cylinder body (1), and the sealing member is arranged between the outer peripheral wall of the piston (2) and the inner wall of the cylinder body (1).

4. The double-acting integrated hydraulic nut according to claim 1, characterized in that: The pressurized oil port of the cylinder (1) is connected to a double-acting stretching hydraulic pump station via a quick-change joint, and the pressure control system of the double-acting stretching hydraulic pump station includes a proportional relief valve and a digital pressure sensor.

5. The double-acting integrated hydraulic nut according to claim 1, characterized in that: The inner hole of the locking sleeve (6) is provided with a hexagonal cavity that cooperates with the bolt head to prevent rotation, and an axial positioning structure is provided between the locking sleeve (6) and the bottom surface of the cylinder body (1).

6. The double-acting integrated hydraulic nut according to claim 1, characterized in that: The inner profile of the locking sleeve (6) matches the outer hexagonal profile of the locking nut (4), and the electric wrench (7) transmits torque to the locking nut (4) by driving the locking sleeve (6) to rotate.

7. The double-acting integrated hydraulic nut according to claim 1, characterized in that: The piston working area of ​​the cylinder (1) is 7000-7100 mm², the maximum working pressure of the hydraulic system is 200 MPa, and the effective stroke of the piston (2) is 15-25 mm.

8. A hydraulic nut system, characterized in that: It comprises a double-acting integrated hydraulic nut and a double-acting stretching hydraulic pump station as described in any one of claims 1 to 7, wherein the hydraulic pump station is connected to the pressurized oil port of the cylinder body (1) through a quick-change joint; the pressure control system of the hydraulic pump station includes a proportional relief valve and a digital pressure sensor; the hydraulic pump station is configured to supply oil to the hydraulic oil chamber in both directions to control the extension and retraction of the piston (2).

9. A hydraulic nut system according to claim 8, characterized in that: The double-acting stretching hydraulic pump station comprises an electro-hydraulic proportional reversing valve and a high-pressure accumulator; the electro-hydraulic proportional reversing valve is controlled in conjunction with a proportional relief valve to achieve stepless adjustment of the extension / retraction speed of the piston (2); the high-pressure accumulator is connected to the oil outlet pipeline of the pump station to stabilize system pressure fluctuations.

10. A hydraulic nut system according to claim 8 or 9, characterized in that: The oil circuit system of the hydraulic pump station adopts a parallel dual oil circuit design, wherein the first oil circuit is connected to the pressurized oil chamber to control the extension of the piston (2), and the second oil circuit is connected to the retraction oil chamber to control the retraction of the piston (2); both oil circuits are provided with independent pressure sensors and safety pressure relief valves.

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