Hydraulic bolt tensioner

Abstract

The utility model relates to the technical field of bolt assembly, in particular to a hydraulic bolt tensioner. The hydraulic bolt tensioner comprises a tensioner body, a supporting seat is arranged at the bottom of the tensioner body, a shifting sleeve used for screwing a target nut is rotationally installed in the supporting seat, an electric control gear set in meshing transmission with the shifting sleeve is arranged on the side of the supporting seat, a driving motor is arranged on the electric control gear set, and the driving motor is provided with a control device. The control device can enable the driving motor to rotate forwards to fasten the target nut and can enable the driving motor to rotate reversely to disassemble the target nut. Different working modes can be seamlessly switched without additionally configuring other tools for disassembling the target nut, continuous operation from fastening to disassembling of the target nut is achieved, an operator only needs to set a pressure value, select working conditions and start a control device according to the specification of the target bolt in the whole process, and the operation efficiency is greatly improved. And the stretching, fastening or dismounting process of the target bolt can be automatically completed without manually screwing the gear box, so that the labor intensity is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of bolt assembly, in particular to a hydraulic bolt tensioner. Background Art

[0002] As a bolt pre-tightening and removal tool, the hydraulic bolt tensioner uses hydraulic pressure to directly apply tension to the bolt, causing the bolt to be stretched within the elastic deformation area, thereby achieving bolt tightening or removal.

[0003] Prior art, such as the Chinese utility model patent with authorization announcement number CN218874369U, discloses a hollow bolt tensioner, which specifically discloses a tensioner body, which is composed of a base, a lower oil cylinder, an upper oil cylinder and a top cover assembly in order from bottom to top along its radial direction, and a tensioning nut penetrating the lower oil cylinder and the upper oil cylinder is installed in the tensioner body, and the inner wall of the tensioning nut is provided with a thread adapted to the stud. When in use, the bottom of the base is aligned with the bolt to be operated, so that the gear puller sleeve is sleeved on the nut, and the conversion head is rotated to rotate the tensioning nut downward, and then the bolt is extended into the threaded hole of the tensioning nut. The oil pipe is connected by the connecting handle, so that the upper and lower double oil cylinders work synchronously, increasing the preload force to obtain higher safety. The tensioning nut moves upward and then pulls the bolt upward, applying tensioning force to the bolt, and then the gear box drives the gear puller sleeve to rotate and tighten the nut.

[0004] While the aforementioned hollow bolt tensioner can tighten the nut more, the tightening process requires the operator to use a wrench to rotate the gearbox. Due to the friction between the bolt and the nut, the operator needs to apply considerable force to turn the wrench, which is labor-intensive. Furthermore, when operating bolts in a confined space, even if the operator can barely install the bolt tensioner on the bolt, it is impossible to insert a tool such as a wrench into the gearbox and apply sufficient force to rotate it, making it impossible to pre-tighten or remove the bolt in a confined space. Utility Model Content

[0005] The purpose of the utility model is to provide a hydraulic bolt tensioner to solve the problem that the bolt tensioner in the prior art is not only labor-intensive in actual use but also cannot realize the pre-tightening or disassembly operation of the bolt in a limited space.

[0006] To achieve the above-mentioned purpose, the technical solution of the hydraulic bolt tensioner provided by the utility model is: the hydraulic bolt tensioner includes a tensioner body, the bottom of the tensioner body has a support seat, a pull sleeve for screwing the target nut is rotatably installed in the support seat, an electronically controlled gear set that meshes with the pull sleeve for transmission is provided on the side of the support seat, a drive motor is provided on the electronically controlled gear set, and the drive motor is equipped with a control device. The control device can make the drive motor rotate forward to tighten the target nut, and can make the drive motor reverse to remove the target nut.

[0007] As a further improvement, a limit switch for cooperating with the target nut is provided above the pull sleeve on the support seat. The limit switch and the drive motor are respectively connected to the control device. When the limit switch is triggered during the removal of the target nut, the control device controls the drive motor to stop and reverse so that the target nut touches the limit switch, indicating that the target nut is removed in place.

[0008] As a further improvement, in the axial projection of the pull sleeve, the contact of the limit switch extends into the inner hole of the pull sleeve and is located close to the inner circumferential surface of the pull sleeve.

[0009] As a further improvement, the driving motor is a DC reduction motor.

[0010] As a further improvement, the DC reduction motor extends in the same direction as the stretcher body.

[0011] As a further improvement, the electronically controlled gear set is a reduction gear set.

[0012] As a further improvement, the manual gear set and the electronically controlled gear set on the support base are symmetrically arranged with respect to the support base.

[0013] As a further improvement, both the electronically controlled gear set and the manual gear set are two-stage gear sets.

[0014] As a further improvement, an oil inlet is opened on the stretcher body on the other side relative to the drive motor, and an oil inlet connector for connecting with the hydraulic pump station is provided at the oil inlet. The oil inlet connector extends vertically and is arranged above the manual gear set.

[0015] As a further improvement, the control device is a PLC controller.

[0016] The beneficial effect is that the present invention provides a hydraulic bolt tensioner that is improved on the basis of the existing technology. Compared with the existing technology, electric control is added, and the tightening and removal of the target nut can be achieved during the forward and reverse rotation of the drive motor. During the entire process, the operator only needs to output different instructions through the control device, that is, the two working modes for the target bolt can be seamlessly switched, without the need to use other tools such as wrenches for removing the target nut, and without manually twisting the gear set, which greatly reduces the labor intensity. In addition, the hydraulic bolt tensioner only needs to be inserted into a limited space, and the tightening and removal of the target bolt can be completed without using tools such as wrenches in the limited space. Through the control device and the drive motor, it has better operability when used in a small space. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A cross-sectional view of an embodiment of the hydraulic bolt tensioner provided by the utility model;

[0018] Figure 2 This is a front view of the hydraulic pump station and PLC in one embodiment of the hydraulic bolt tensioner provided by the utility model;

[0019] Figure 3 This is a control flow chart of an embodiment of the hydraulic bolt tensioner provided by the utility model;

[0020] In the figure: 1. Hydraulic cylinder; 2. Piston; 3. Support seat; 4. Electronically controlled gear set; 5. Screw sleeve; 6. Limit switch; 7. Tensile head; 8. Top cover; 9. Compression spring; 10. Oil inlet; 11. Oil inlet connector; 12. First sealing ring; 13. Second sealing ring; 14. Reducer; 15. Motor body; 16. Hydraulic pump station; 17. PLC controller; 18. Manual gear set. DETAILED DESCRIPTION

[0021] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0022] As a bolt pre-tightening and removal tool, the hydraulic bolt tensioner uses hydraulic pressure to apply tension to the bolt, causing it to be stretched within the elastic deformation area, thereby achieving tightening or removal. However, the hydraulic bolt tensioner in the prior art cited in the background technology still requires the operator to use a tool such as a wrench to rotate and remove the nut. Using a wrench to rotate the gearbox requires a large torque, especially during the bolt tightening or removal process. Due to the friction between the bolt and the nut, the operator needs to apply a large force to turn the wrench, which is labor-intensive and may also cause fatigue or injury to the operator's hands. In addition, in a small space, the wrench used in conjunction may be difficult to reach the position of the gearbox. Even if it can be reached, it may not be able to fully apply force or rotate due to space limitations. Based on this, the utility model is improved on the basis of the prior art and provides a hydraulic bolt tensioner to solve the problems existing in the above-mentioned prior art.

[0023] The overall design concept of the hydraulic bolt tensioner provided by the utility model is: the hydraulic bolt tensioner integrates automatic tightening and disassembly functions, and uses the drive motor and control device instructions to realize the automatic disassembly of the target nut. No additional tools are required, and no manual operation by the operator is required, and the tightening and disassembly of the target bolt can be completed.

[0024] Specifically, as a basic technical solution, Figure 1-3As shown, the core component of the hydraulic bolt tensioner is the bolt tensioner body, which includes a hydraulic cylinder 1, in which a piston 2 is slidably mounted. The piston 2 is provided with a tensioning head 7 that can be rotatably mounted on the target bolt. The tensioning head 7 connects the bolt tensioner body to the target bolt, so that when the piston 2 moves, it causes the target bolt to extend together, allowing the target bolt to be stretched within its elastic deformation range, providing a convenient foundation for subsequent pre-tightening and removal work. The bolt tensioner body has a support base 3 fixed to the bottom of its hydraulic cylinder 1. The support base 3 is provided with a shifting sleeve 5 that can be mounted on the outside of the target nut. The support base 3 is also provided with an electronically controlled gear set 4 that meshes with the shifting sleeve 5. The electronically controlled gear set 4 is equipped with a drive motor and a control device. The control device sends instructions to the drive motor. During the forward rotation of the drive motor, the shifting sleeve drives the nut, thereby driving the target nut to rotate, thereby tightening the target nut. When the drive motor receives the instruction and reverses, it drives the shifting sleeve to reverse the target nut, thereby removing the target nut.

[0025] The hydraulic bolt tensioner provided by the present invention does not require the replacement of other operating tools. The operator only needs to set the pressure value required to stretch the target bolt to the set range according to the specifications of the target bolt, and select the working condition to enable the drive motor to remove and tighten the target bolt. It can seamlessly switch between tightening and disassembly operations, realizing the automation of bolt tightening and disassembly. There is no need to manually use tools such as wrenches to twist the gear set, which greatly reduces labor intensity and can maintain continuous operation. There is no need for the operator to frequently change tools or adjust positions, thereby improving work efficiency. At the same time, compared with the existing technology that requires the use of wrenches or the like to twist the gear box in a limited space, the hydraulic bolt tensioner provided by the present invention can complete the tightening and disassembly of bolts without additional tools, and is more suitable for limited spaces.

[0026] Based on the above overall introduction to the hydraulic bolt tensioner of the present invention, a more specific embodiment is provided below on the basis of the overall introduction:

[0027] This embodiment focuses on the detailed description of the specific assembly of the control device and the drive motor and how to coordinate their operation.

[0028] like Figure 1 As shown, a limit switch 6 is provided on the support seat 3 in the moving direction of the target nut being screwed, and the limit switch 6 is located on the moving path of the target nut during the process of screwing the target nut by the sleeve. When the drive motor is in the reversal process, when the target nut touches the limit switch 6, it indicates that the target nut has been disassembled into place.

[0029] The limit switch 6 includes a contact. In the axial projection of the pull sleeve, the contact of the limit switch extends into the inner hole of the pull sleeve and is located close to the inner circumferential surface of the pull sleeve. The contact is used to contact with the target nut during the removal process of the target nut to transmit a target nut in place signal. When the pull sleeve moves the target nut so that the target nut is screwed out toward the upper side of the pull sleeve, the target nut contacts the contact to transmit the nut removal in place signal without affecting other operations during the tightening and removal of the target bolt.

[0030] The electronically controlled gear set 4 is mounted near the bottom of the support base 3. The output gear of the electronically controlled gear set 4 meshes with the outer ring gear of the pull sleeve 5. A drive motor is fixed to the upper side of the electronically controlled gear set 4, and the motor shaft of the drive motor is coaxially connected to the input gear of the electronically controlled gear set. The drive motor is activated to rotate the pull sleeve with the internal gear of the electronically controlled gear set. In this embodiment, the drive motor is a DC motor. During the process of stretching the target bolt, a large initial force is required to overcome the static friction between the target bolt and the target nut. A DC motor is preferably used because it can accelerate from a stationary state to a set speed in a short time, thereby improving the stretching efficiency. In addition, the DC motor has a relatively simple structure and low manufacturing cost, which is more compatible with the current high demand for bolt tensioners. Of course, in other embodiments, the drive motor can also be a servo motor.

[0031] like Figure 1 As shown, the DC motor is a DC reduction motor, including a motor body 15 and a reducer 14. The reducer 14 is arranged between the motor body 15 and the electronically controlled gear set 4, and the motor body 15 and the reducer 14 are arranged vertically above the electronically controlled gear set 4. This can save the lateral footprint of the hydraulic bolt tensioner. In practice, it is easier to insert the hydraulic bolt tensioner between two relatively close target bolts and allow the pull sleeve 5 to be placed on the target nut, thereby increasing the scope of use. The reducer 14 transmits power to the electronically controlled gear set 4 via the transmission shaft. The electronically controlled gear set 4 is a reduction gear set whose transmission ratio can be adjusted according to actual needs to achieve secondary reduction. The setting of the reduction DC motor can increase the torque of the output shaft to meet work requirements.

[0032] More preferably, Figure 2 As shown, the control device is a PLC controller 17. PLC controller 17 operates reliably and stably, and can ensure that target bolts of varying specifications and models are stretched within their deformation ranges, facilitating subsequent tightening and removal operations. PLC controller 17 is also equipped with a relay that detects current levels and determines the current overload value to determine whether the target nut is properly tightened.

[0033] like Figure 1-Figure 2As shown, the main body of the hydraulic bolt tensioner is provided with an oil inlet 10 on its hydraulic cylinder. The oil inlet 10 is communicated with the inner cavity of the hydraulic cylinder 1. An oil inlet joint 11 is provided at the oil inlet 10. The other end of the oil inlet joint 11 is communicated with the hydraulic pump station 16. After the hydraulic pump station 16 is started, the oil pump of the hydraulic pump station 16 starts to supply oil, and the high-pressure oil is delivered to the bolt tensioner through the oil inlet joint 11. In addition, the oil inlet joint can be adapted to oil inlet pipes of different specifications. The oil inlet and the oil inlet head can also facilitate the injection or discharge of hydraulic oil into or out of the hydraulic cavity of the hydraulic cylinder.

[0034] The following, combined Figure 3 Describe the detailed working process:

[0035] Place the bolt tensioner's sleeve over the target nut. Insert the target bolt into the support seat and secure it to the piston via a threaded connection. Set the required pressure on the hydraulic pump station and adjust it according to the target bolt's specifications and tightening requirements. Select the pre-tightening or removal mode and start the hydraulic pump station. The hydraulic pump station begins supplying oil, powering the bolt tensioner. The piston in the hydraulic cylinder begins to move under the influence of the oil pressure, pulling the target bolt together.

[0036] During the stretching process, the hydraulic pump station will monitor the changes in oil pressure in real time, and send a pressure-in-place signal to the PLC controller after the oil supply is in place.

[0037] After receiving the pressure-reaching signal, the PLC controller 17 converts the signal into a control command and sends it to the DC reduction motor. The DC reduction motor begins to rotate forward, transmitting power to the support base 3 and the shifting sleeve 5 via the electronically controlled gear set 4. The shifting sleeve 5 then drives the target nut to begin forward rotation and tightening. During the tightening process, the PLC controller 17 controls the DC reduction motor's current overload value via a relay to determine whether the target nut is properly tightened.

[0038] When the target nut needs to be removed, the PLC controller 17 will issue a command to reverse the DC reduction motor, and the pull sleeve 5 will rotate in the opposite direction to drive the target nut to start reverse removal. When the target nut is screwed until it touches the contact of the limit switch 6, it indicates that the target nut has been removed. After receiving the signal from the limit switch 6, the PLC controller 17 will stop the operation of the DC reduction motor and issue a prompt indicating that the removal is complete.

[0039] In this embodiment, the electronically controlled gear set is a two-stage gear set. The meshing of the two gears in the secondary gear set achieves a greater reduction ratio than a single-stage gear set. This results in a lower output speed at the same input speed, resulting in greater torque output. This more effectively transmits the torque amplified by the secondary gear set, helping to ensure that the target bolt can be securely tightened or quickly removed. Furthermore, within limited space, the design of the secondary gear set allows the electronically controlled gear set and manual gear set to be relatively compact while still maintaining a high transmission ratio and torque transmission capacity, making it easier for the shifting sleeve to fit over the target nut.

[0040] Based on the above overall introduction to the hydraulic bolt tensioner of the present invention, a more specific embodiment is provided below on the basis of the overall introduction:

[0041] This embodiment focuses on a detailed description of the specific structure of the hydraulic bolt tensioner.

[0042] like Figure 1 As shown, the shifting sleeve 4 is also equipped with a manual gear set 18, which is used to drive the shifting sleeve in conjunction with an operating tool. This manual gear set 18 serves as an emergency backup. In the event of a failure in the control device or drive motor, the operator uses a torque wrench to operate the manual gear set 18. By manually rotating the gears in the manual gear set 18, the shifting sleeve rotates, tightening or removing the target nut, thus avoiding downtime caused by automation failures. Furthermore, the manual gear set 18 is not affected by abnormal conditions such as power outages and electromagnetic interference, ensuring continuous and stable operation. Specifically, in this embodiment, the manual gear set is a two-stage gear set, and a manual gear set 18 and an electronically controlled gear set 4 are respectively assembled on opposite sides of the pull sleeve 5. In order to optimize the structure of the bolt tensioner so that it can be more adaptable to limited space operations, one end of the above-mentioned pull sleeve 5 is engaged with the electronically controlled gear set 4, and the motor body 15 and the reducer 14 are vertically extended above the electronically controlled gear set 4. On the basis of this, the other end of the pull sleeve 5 is engaged with the manual gear set 18, further optimizing the layout of the hydraulic bolt tensioner to improve its applicability for narrow space operations. The oil inlet connector 11, the motor body 15 and the reducer 14 are respectively vertically arranged on opposite sides of the tensioner body, so that the center of gravity of the hydraulic bolt tensioner is close to the middle, making it more stable during use.

[0043] The target bolt is fixedly connected to the piston 2 via the stretching head 7, so that the target bolt can be stretched when the oil enters the hydraulic cylinder to push the piston to move. Figure 1As shown, a threaded hole is formed in the tensioning head 7, through which the target bolt is screwed to the tensioning head 7, thereby achieving fixation with the piston 2. In addition, multiple tensioning heads with threaded holes of different inner diameters can be configured, so that target bolts of different models and sizes can be pre-tightened and removed.

[0044] Specifically, a piston step surface is provided on the piston, and an annular boss is provided on the outer periphery of the stretching head to cooperate with the piston step surface. The annular boss of the stretching head is stopped by the piston step surface, so that during the movement of the piston, the stretching head can be pushed to move, thereby lengthening the target bolt.

[0045] A top cover 8 is fixed to the top of the hydraulic cylinder 1, and a compression spring 9 is arranged between the side of the annular boss that is opposite to the piston step surface and the top cover 8 and the stretching head. When the hydraulic cylinder 1 is filled with oil and the piston 2 moves downward to stretch the target bolt, the compression spring 9 is compressed to absorb energy, and after the pre-tightening and disassembly operations of the target bolt are completed, the compression spring 9 is reset to reset the piston 2, so as to facilitate the operation of the next target bolt.

[0046] A sealing ring is installed at the position where the piston 2 cooperates with the cylinder body of the hydraulic cylinder 1. The cylinder body of the hydraulic cylinder 1 is provided with a cylinder step surface. The outer periphery of the piston includes a large diameter section and a small diameter section that cooperate with the cylinder step surface. For ease of description, a first sealing ring 12 is installed between the large diameter section of the piston 2 and the cylinder body, and a second sealing ring 13 is installed between the small diameter section of the piston 2 and the cylinder body. The provision of the first and second sealing rings provides double sealing protection for the hydraulic cylinder. Even if one of the sealing rings is slightly worn or leaks, the other sealing ring can continue to work effectively to prevent oil leakage, helping to reduce the loss and contamination of hydraulic oil, thereby extending the service life of the hydraulic cylinder, ensuring the normal operation of the hydraulic bolt tensioner, and reducing the downtime and maintenance costs caused by leakage and other problems. In addition, the provision of the two sealing rings enables the hydraulic cylinder to quickly respond to control instructions during operation and achieve precise motion control.

[0047] It should be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0048] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the description and drawings of the present invention shall also be included in the scope of protection of the present invention.

Claims

1. A hydraulic bolt tensioner, comprising a tensioner body, a bottom portion of which has a support seat, a pull sleeve rotatably mounted in the support seat for tightening a target nut, and characterized by: An electronically controlled gear set is arranged on the side of the support seat and is engaged with the pull sleeve for transmission. A drive motor is arranged on the electronically controlled gear set. The drive motor is equipped with a control device. The control device can make the drive motor rotate forward to tighten the target nut, and can make the drive motor rotate backward to remove the target nut.

2. The hydraulic bolt tensioner according to claim 1, characterized in that: A limit switch for cooperating with the target nut is provided above the pull sleeve on the support seat. The limit switch and the drive motor are respectively connected to the control device. When the limit switch is triggered during the removal of the target nut, the control device controls the drive motor to stop and reverse so that the target nut touches the limit switch, indicating that the target nut is removed in place.

3. The hydraulic bolt tensioner according to claim 2, characterized in that: In the axial projection of the dial sleeve, the contact of the limit switch extends into the inner hole of the dial sleeve and is located close to the inner circumferential surface of the dial sleeve.

4. The hydraulic bolt tensioner according to any one of claims 1 to 3, characterized in that: The driving motor is a DC reduction motor.

5. The hydraulic bolt tensioner according to claim 4, characterized in that: The DC reduction motor and the stretcher body have the same extension direction.

6. The hydraulic bolt tensioner according to any one of claims 1 to 3, characterized in that: The electronically controlled gear set is a reduction gear set.

7. The hydraulic bolt tensioner according to claim 6, characterized in that: The manual gear set and the electronically controlled gear set on the supporting seat are symmetrically arranged with respect to the supporting seat.

8. The hydraulic bolt tensioner according to claim 7, characterized in that: Both the electronically controlled gear set and the manual gear set are two-stage gear sets.

9. The hydraulic bolt tensioner according to claim 7, characterized in that: An oil inlet is provided on the main body of the device on the other side relative to the drive motor. An oil inlet connector for communicating with the hydraulic pump station is provided at the oil inlet. The oil inlet connector extends vertically and is provided above the manual gear set.

10. The hydraulic bolt tensioner according to any one of claims 1 to 3, characterized in that: The control device is a PLC controller.

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