A new type of slewing bearing bolt mounting method

Abstract

The application discloses a novel installation method of rotary supporting bolts, wherein the upper end of the bolt is put into the bolt installation hole of the rotary supporting through a steel wire rope tensioning device, the other end corresponding to the steel wire rope tensioning device is fixed with an electric push rod, the bolt is pushed into the installation required position through the axial extension and retraction of the electric push rod, after the bolt is pushed into the specified position, the electric push rod is retracted to the initial position, and the rotary supporting is rotated to the position where the nut tightening device is located; after the bolt to be installed is rotated to the corresponding position, the nut on the bolt is tightened through the tightening device to reach the required installation torque; compared with the traditional method, the installation method can accurately align the bolt with the hydraulic stretcher in a relatively narrow space, so that the rotary supporting bolt is accurately installed, and the problem that the bolt is difficult to be installed in the traditional method in the narrow space is solved.

Description

Technical Field

[0001] This invention relates to a method for installing a slewing bearing, specifically a novel method for installing slewing bearing bolts. Background Technology

[0002] The slewing bearing of a tower crane must withstand axial loads from the lifting load and the self-weight of the tower top, as well as the radial force output by the slewing mechanism. Simultaneously, it must resist the overturning moment generated by the load and wind loads. Therefore, the slewing bearing is a critical load-bearing component of the tower crane. Its performance directly determines the tower crane's usability and safety performance; its material properties and load-bearing capacity must meet the tower crane's design requirements. In addition to calculation and selection, extra attention must be paid to its correct installation and use. Otherwise, the damage caused by improper installation or use cannot be ignored.

[0003] like Figure 1-2 As shown, the traditional slewing bearing bolt installation structure uses a tightening device, which includes a hydraulic jack and a hydraulic tensioner. The traditional slewing bearing bolt installation method steps are as follows:

[0004] First, install the hydraulic jack on the fixed structure. Then, connect the hydraulic tensioner to the hydraulic jack, and return the hydraulic jack cylinder to its original position. Manually tighten the nut on the upper end of the bolt to the appropriate installation position. Then, using a lifting device or other method, pass the bolt through the mounting hole of the slewing bearing. Next, manually adjust the bolt position little by little, pre-tightening the nut to the required torque. Then, extend the hydraulic jack cylinder, raising the hydraulic tensioner. Continuously adjust the extension length of the hydraulic jack to achieve a precise fit between the hydraulic tensioner and the nut. Finally, activate the hydraulic tensioner to stretch the bolt, and use tools to tighten the bolt to the required torque.

[0005] The installation of bolts for traditional slewing bearings can be done manually. For bolts on larger slewing bearings, one end of the bolt is usually fixed manually, while the other end is installed using a hydraulic tensioner. For bolts on ultra-large slewing bearings, the tensioner is usually heavy, inconvenient to operate, and difficult to install. A combination of a hydraulic tensioner and a hydraulic jack cylinder is typically used. The nut is manually installed at one end, and then the bolt is hoisted and the nut is pre-tightened. However, this requires continuous manual adjustment of the bolt position and the extension length of the hydraulic jack cylinder to achieve accurate alignment between the hydraulic tensioner and the bolt. In confined spaces, directly hoisting the bolt to the hydraulic tensioner position from top to bottom and achieving accurate alignment is quite difficult. This traditional installation method is more difficult and labor-intensive than using only a hydraulic tensioner and a jack.

[0006] Due to the large size, complex structure, and limited internal space of the slewing bearings used, the bolts used to fix the slewing bearings to the upper and lower supports are much larger and heavier than those used for other slewing bearings. Therefore, traditional installation methods using manual labor or simple mechanical devices are not suitable for installing these slewing bearing bolts. The traditional hydraulic tensioner installation method commonly used in the industry is also limited by the size and weight of the bolts and nuts, as well as the size and weight of the hydraulic tensioner itself. Within the limited installation space, the conventional installation method using hydraulic tensioners is not sufficient for the installation work. Therefore, there is an urgent need for a new installation method to solve the above problems. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a novel method for installing slewing bearing bolts. It improves upon the original method by solving the problem of bolt-hydraulic tensioner mating. The problem can be solved by adding an electric push rod. First, the bolt is pushed into the appropriate installation position with the help of the electric push rod. Then, by returning and repositioning, the bolt is accurately moved above the hydraulic tensioner, thus easily achieving the mating of the bolt and the hydraulic tensioner.

[0008] This method is suitable for bottom-up bolt installation in situations where installation space is limited. First, the upper end of the bolt is inserted into the bolt mounting hole via a wire rope tensioning device. An electric push rod is fixed to the other end of the wire rope tensioning device. The axial extension and retraction of the electric push rod pushes the bolt into the required installation position. Simultaneously, the tensioning device at the upper end of the bolt adjusts synchronously with the electric push rod to prevent misalignment of the bolt during subsequent movement, which would affect its use. After the bolt is pushed into the designated position, the electric push rod retracts to its initial position, and the slewing bearing rotates to the position of the nut tightening device. The tightening device consists of a jack cylinder and a hydraulic tensioner. After the bolt to be installed rotates to the corresponding position, the nut is pre-tightened to the required torque. Then, the jack fixed below lifts the hydraulic tensioner to the nut position, and the hydraulic tensioner operates to bring the nut to the required installation torque. The jack cylinder then retracts, causing the hydraulic tensioner to return to its initial position.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A novel method for installing slewing bearing bolts, comprising: firstly, inserting the upper end of the bolt into the bolt mounting hole of the slewing bearing via a wire rope tensioning device; fixing an electric push rod at the other end corresponding to the wire rope tensioning device; pushing the bolt into the required installation position by axial extension and retraction of the electric push rod; after the bolt is pushed into the designated position, retracting the electric push rod to the initial position, and rotating the slewing bearing to the position of the nut tightening device; after the bolt to be installed has rotated to the corresponding position, tightening the nut on the bolt to achieve the required installation torque by the tightening device.

[0010] Furthermore, when the axial extension and retraction of the electric push rod pushes the bolt into the required installation position, the tensioning device at the upper end of the bolt will adjust synchronously with the electric push rod to prevent the bolt from being misaligned during subsequent movement, thus affecting its use.

[0011] Furthermore, the tightening device consists of a jack cylinder and a hydraulic tensioner.

[0012] Furthermore, after the bolts to be installed are rotated to the corresponding positions, the nuts are pre-tightened. Then, the jacks fixed below will lift the hydraulic tensioner to the nut position, and the hydraulic tensioner will work to bring the nut to the required installation torque.

[0013] Furthermore, once the nut reaches the required installation torque, the jack cylinder retracts, causing the hydraulic tensioner to retract to its initial position.

[0014] Furthermore, a hydraulic tensioner is a device that uses the tension generated by an oil pump to stretch the bolt within its elastic deformation zone, causing slight deformation of the bolt diameter, thereby making the nut easier to loosen and install.

[0015] Furthermore, an electric linear actuator is a device that uses a motor, reducer, and lead screw mechanical structure to achieve telescopic reciprocating motion. After the motor is reduced in speed by the reducer, it drives a pair of lead screw nuts to work, converting the rotational motion of the motor into linear motion. The extension and retraction of the linear actuator is completed by using the forward and reverse rotation of the motor.

[0016] Furthermore, the electric push rod is mounted on the lower mounting bracket of the slewing bearing through a bottom fixing structure and a side fixing structure.

[0017] Furthermore, the bolts are hoisted to the vicinity of the electric push rod via the upper fixed wire rope hoisting equipment through the mounting hole. The bolts are then manually adjusted to fit against the push rod mounting plate of the electric push rod. Subsequently, the electric push rod controller is manually controlled to make the mounting plate at the upper end of the push rod contact the bolt. The push rod extends a certain distance according to the actual situation, so that the bolt reaches the required installation position in the axial direction, thus completing the calibration of the bolt installation position.

[0018] Furthermore, before achieving the required installation torque by tightening the nuts on the bolts, it is necessary to confirm the following steps: After the bolts are stable, reconfirm whether the bolt position meets the installation requirements. If there is a deviation in the bolt position, it is necessary to manually adjust it or return the bolt to the original calibration position for recalibration. After the bolts meet the installation requirements, pre-tighten the nuts, and then start the hydraulic jack to push the hydraulic tensioner upward to the required position for precise engagement with the nuts.

[0019] The beneficial effects of this invention are:

[0020] (1) This method uses an electric push rod to position the bolts and uses a combination of a hydraulic tensioner and a jack cylinder to install the bolts and nuts on the slewing bearing. It is easy to operate, reduces the labor intensity of workers, and improves the installation efficiency.

[0021] (2) Compared with the traditional method, this installation method can accurately align the bolts with the hydraulic tensioner in a relatively narrow space, thereby achieving precise installation of the slewing bearing bolts and solving the problem of difficulty in installing bolts in a narrow space using the traditional method. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a traditional nut tightening device.

[0023] Figure 2 This is a schematic diagram of the traditional slewing bearing bolt installation steps;

[0024] Figure 3 This is a layout diagram of the equipment used in the novel slewing bearing bolt installation method of the present invention;

[0025] Figure 4 A schematic diagram of the structure for calibrating the bolt installation position;

[0026] Figure 5 A schematic diagram illustrating the installation steps of the new bolt installation method;

[0027] In the diagram: 1. Electric push rod; 2. Hydraulic jack; 3. Hydraulic tensioner; 4. Bottom fixing structure; 5. Lateral fixing structure. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0030] A novel method for installing bolts on slewing bearings, the equipment used in this method and its layout are as follows. Figure 3 As shown, the end of the jack piston rod is constrained to the hydraulic tensioner by bolts to prevent the hydraulic tensioner from shifting and affecting the installation of the nut.

[0031] The equipment used in a novel slewing bearing bolt installation method includes: an electric push rod, a hydraulic jack, a hydraulic tensioner, a bottom fixing structure, and a side fixing structure. The novel slewing bearing bolt installation method is as follows:

[0032] like Figure 3 , 5 As shown, first, fix the electric actuator, hydraulic jack, and hydraulic tensioner in their respective positions. Retract the hydraulic cylinder of the electric actuator and hydraulic jack to their original positions. The bolt is hoisted through the mounting hole to near the top of the electric actuator using a wire rope hoisting device fixed at the top. Manually adjust the bolt to ensure it is flush with the actuator's mounting plate. Then, manually control the electric actuator controller to bring the mounting plate at the top of the actuator into contact with the bolt. The actuator extends a certain distance as needed, aligning the bolt axially to the required installation position, thus calibrating the bolt's installation position. Next, control the rotation and bolt tightening equipment to slowly move the bolt above the hydraulic tensioner. After the bolt stabilizes, reconfirm that the bolt position meets the installation requirements. If there is a deviation, manually adjust or return the bolt to its original calibration position for recalibration. Once the bolt meets the installation requirements, pre-tighten the nut, then activate the hydraulic jack to push the hydraulic tensioner upwards to the required position, precisely engaging with the nut. Start the hydraulic push rod tensioner to pull the bolt downwards, use tools to tighten the nut, tighten it to 100% of the specified bolt torque, and install the bolt in place using this new installation method.

[0033] like Figure 4 As shown, the bottom fixing structure and the side fixing structure of the electric push rod are used to fix the electric push rod body and the sleeve respectively. The electric push rod is installed on the lower mounting bracket of the slewing bearing. The electric push rod can extend and retract a certain distance axially, which is responsible for the axial positioning of the bolt.

[0034] 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 or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A novel method for installing slewing bearing bolts, characterized in that, include: First, the upper end of the bolt is inserted into the bolt mounting hole of the slewing bearing via a wire rope tensioning device. An electric push rod is fixed to the other end of the bolt, corresponding to the wire rope tensioning device. The bolt is pushed into the required installation position via the axial extension and retraction of the electric push rod. After the bolt is pushed into the designated position, the electric push rod retracts to its initial position, and the slewing bearing rotates to the position of the nut tightening device. After the bolt to be installed rotates to the corresponding position, the nut on the bolt is tightened by the tightening device to achieve the required installation torque. When the axial extension and retraction of the electric push rod pushes the bolt into the required installation position, the tensioning device at the upper end of the bolt will adjust synchronously with the electric push rod to prevent the bolt from being misaligned during subsequent movement, thus affecting its use. The bolts are hoisted to the vicinity of the electric push rod via the upper wire rope hoisting equipment through the mounting hole. The bolts are then manually adjusted to fit against the push rod mounting plate of the electric push rod. Subsequently, the electric push rod controller is manually controlled to make the mounting plate at the upper end of the push rod contact the bolt. The push rod extends a certain distance according to the actual situation, so that the bolt reaches the required installation position in the axial direction, thus completing the calibration of the bolt installation position.

2. The installation method of a novel slewing bearing bolt according to claim 1, characterized in that, The tightening device consists of a jack cylinder and a hydraulic tensioner.

3. The method for installing a novel slewing bearing bolt according to claim 2, characterized in that, After the bolts to be installed are rotated to the corresponding positions, the nuts are pre-tightened. Then, the jacks fixed below will lift the hydraulic tensioner to the nut position. The hydraulic tensioner will work to bring the nut to the required installation torque.

4. The method for installing a novel slewing bearing bolt according to claim 3, characterized in that, Once the nut reaches the required installation torque, the jack cylinder retracts, causing the hydraulic tensioner to return to its initial position.

5. The method for installing a novel slewing bearing bolt according to claim 3, characterized in that, A hydraulic tensioner is a device that uses the tension generated by an oil pump to stretch a bolt within its elastic deformation zone, causing a slight deformation of the bolt diameter, thereby making the nut easier to loosen and install.

6. The method for installing a novel slewing bearing bolt according to claim 1, characterized in that, An electric linear actuator is a device that uses a motor, reducer, and lead screw to achieve telescopic reciprocating motion. After the motor is reduced in speed by the reducer, it drives a pair of lead screw nuts to work, converting the motor's rotational motion into linear motion. The extension and retraction of the linear actuator are completed by using the forward and reverse rotation of the motor.

7. The method for installing a novel slewing bearing bolt according to claim 1, characterized in that, The electric push rod is mounted on the lower mounting bracket of the slewing bearing through a bottom fixing structure and a side fixing structure.

8. The method for installing a novel slewing bearing bolt according to claim 1, characterized in that, Before tightening the nuts on the bolts to achieve the required installation torque, a confirmation is required. The specific operation is as follows: After the bolts are stable, confirm again whether the bolt position meets the installation requirements. If there is a deviation in the bolt position, it is necessary to manually adjust it or turn the bolt back to the original calibration position and recalibrate it. After the bolts meet the installation requirements, pre-tighten the nuts, and then start the hydraulic jack to push the hydraulic tensioner upward to the required position and precisely match the nut.

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