Method for replacing fan bearing on line

Abstract

The invention relates to a method for replacing a fan bearing on line, which comprises the following steps of: 1, firstly dismounting a fan motor and a coupler on a fan main shaft, and mounting an impeller side fixing tool, 2, dismounting an upper cover of an impeller side bearing seat, separating the bearing from the main shaft, moving the bearing to the side of the motor side bearing, and mounting a motor side fixing tool. And (3) the two bearings and the bearing seats are dismantled, the two bearings and the bearing seats are reinstalled according to the opposite sequence, and the coupler and the motor are installed. According to the technical scheme, the two bearings of the fan can be replaced on line on the basis that a fan shell is not opened. In the process of replacing the bearing, the main shaft of the fan basically does not displace, so that the impeller mounted on the main shaft also basically does not displace, and the impeller and the air inlet do not interfere with each other.

Description

Technical Field

[0001] The invention relates to an online replacement method, in particular to an online replacement method for a fan bearing, and belongs to the technical field of bearing replacement. Background Art

[0002] Single-suction centrifugal fans are also called cantilever centrifugal fans. They are widely used in cold rolling mills. They are mainly used as circulating fans for annealing furnaces and air supply fans for cooling bellows. Cantilever centrifugal fans have a simple structure. Compared with double-suction centrifugal fans with split bearing seats, cantilever centrifugal fans only have one air inlet in the casing, and the pipe connection is simple.

[0003] The circulating fan of the quick cooling section of the annealing furnace has high sealing requirements, so the fan housing is all welded, and the connection between the fan and the annealing furnace pipeline is also all welded to ensure good sealing. However, to replace the fan bearing, the fan needs to be offline, the welds of the fan inlet and outlet pipelines need to be cut off, the welds of the fan housing need to be cut off, the impeller and the main shaft need to be lifted out, and the bearings need to be replaced and reinstalled. This construction workload is large, and the repeated welding effect of the weld part is not good, and the possibility of weld cracking is high, so it is not recommended.

[0004] Through searching, the application publication number CN 206084920 H "Fan Rotor Replacement Device" describes the replacement of fans with split bearing seats. This solution only uses tooling to support the fan main shaft on both sides. After removing the fan air inlet, lift the main shaft together with the impeller by 20cm, and then replace the bearing. This solution is only applicable to fans with split bearing seats, and it is necessary to disassemble the fan housing and remove the air inlet. Although the fan impeller is not lifted out, the weld must be cut off during the disassembly of the fan housing and the disassembly of the air inlet, and then re-welded after reinstallation. There are major hidden dangers, and it is not applicable to fans in the fast cooling section of annealing furnaces. Therefore, a new solution is urgently needed to solve the above technical problems. Summary of the invention

[0005] The present invention is aimed at the problems existing in the prior art and provides a method for online replacement of fan bearings. The technical solution provides a method for online replacement of two bearings of a fan without opening the fan housing. During the bearing replacement process, the fan main shaft has basically no displacement, so the impeller installed on the main shaft has basically no displacement, so there is no interference between the impeller and the air inlet. At present, cantilever fans can generally remove the bearings and bearing seats from the motor side. The mainstream design scheme is to configure two bearings, one large and one small, or to use bearings with tightening sleeves. The early design schemes of disassembling and assembling bearings from the impeller side and the motor side respectively have been basically eliminated. Therefore, the existing cantilever fans are basically applicable to this scheme.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows: a method for online replacement of a fan bearing, the method comprising the following steps:

[0007] Step 1: First remove the fan motor and the coupling on the fan main shaft, and install the impeller side fixing tooling.

[0008] Step 2: Remove the upper cover of the impeller side bearing seat, separate the bearing from the main shaft, move it to the side of the motor side bearing, and install the motor side fixing tooling.

[0009] Step 3: Then remove the two bearings and the bearing seat, reinstall the two bearings and the bearing seat in the reverse order of the above, and install the coupling and the motor.

[0010] As an improvement of the present invention, the fixing tool is designed as a three-body type, which can be conveniently placed at the main shaft of the fan, and the upper and lower parts are connected by two M20 bolts. When installing the fixing tool, first put the two lower parts under the main shaft, fix them on the fan base with M20 bolts, and then install the upper part, which is connected with the two lower parts with two M20 bolts. The center height of the inner hole of the two fixing tools is 2mm higher than the center of the main shaft. The purpose is to fix the main shaft and raise the main shaft by 2mm, which is conducive to moving the bearing seat. Therefore, before installing the tool, loosen the mounting bolts of the bearing seat first, leaving a 2mm lifting space.

[0011] As an improvement of the present invention, step 2 is as follows: loosen the two bearing seat mounting bolts, leave a 2mm lifting space, install the motor side fixing tooling, and the fan status after installation is as follows: Figure 3 In this process, the fan main shaft is fixed by the motor side fixing fixture 3 and two bearing seats.

[0012] As an improvement of the present invention, in step 3, the upper cover of the impeller side bearing seat is removed, the bearing and the main shaft are separated, and the bearing seat is moved to a certain position toward the motor side. During this process, the fan main shaft is fixed by the motor side fixing tooling and the motor side bearing seat.

[0013] As an improvement of the present invention, in the method, the center height of the inner hole is 2 mm higher than the center of the main shaft, the diameter of the inner hole is the same as the diameter of the main shaft at the corresponding position, the two bearing seats of the fan are split bearing seats, the bearings and bearing seats are removed from the motor side, and the bolt holes for installing the tooling are processed on the fan base.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) This technical solution does not require any lifting operation during the entire process, so the fan main shaft bearing can be replaced online, overcoming the difficulty of lifting in certain narrow spaces.

[0016] (2) During the bearing replacement process, the fan main shaft does not move in the axial direction, but only moves 2mm in the height direction, which is smaller than the 4mm-6mm gap between the air inlet and the impeller. Therefore, during the bearing replacement process, there is no interference between the impeller and the air inlet, and the internal structure of the fan will not be damaged.

[0017] (3) During the entire operation, there is no need to disassemble the fan housing and the fan inlet and outlet pipes. This effectively prevents the welding slag generated by gas cutting and welding pipes from falling into the bellows for the fully welded fan circulation system of the rapid cooling section of the annealing furnace. Otherwise, during normal production, the welding slag in the bellows will be blown out and hit the strip steel, resulting in waste.

[0018] (4) Since no gas cutting or welding is performed on the pipeline, the airtightness of the fan circulation system is not damaged, and air will not enter the annealing furnace to produce oxidized color of the strip steel, directly scrapping the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Schematic diagram of cantilever fan structure,

[0020] Figure 2 : Schematic diagram of fixed tooling structure,

[0021] Figure 3 : Schematic diagram of the fan structure with the motor side fixing fixture installed.

[0022] Figure 4 : Schematic diagram of the cantilever fan structure that can directly install two fixed fixtures.

[0023] Figure 5 : Schematic diagram of the structure of the fixed tooling on the impeller side.

[0024] Figure 6 : Schematic diagram of removing the impeller side bearing,

[0025] Figure 7 : Schematic diagram of the fan installed with two fixed fixtures before the bearing is removed.

[0026] Figure 8 : Schematic diagram of the fan status after the bearings and motor are removed.

[0027] In the figure: 1. Motor side bearing, 2. Impeller side bearing, 3. Motor side tooling, 4. Impeller side tooling. DETAILED DESCRIPTION

[0028] In order to deepen the understanding of the present invention, the present embodiment is described in detail below with reference to the accompanying drawings.

[0029] Example 1: See Figure 1 , a method for online replacement of fan bearings, the method comprising the following steps:

[0030] Step 1: First remove the fan motor and the coupling on the fan main shaft, and install the impeller side fixing tooling.

[0031] Step 2: Remove the upper cover of the impeller side bearing seat, separate the bearing from the main shaft, move it to the side of the motor side bearing, and install the motor side fixing tooling.

[0032] Step 3: Then remove the two bearings and the bearing seat, reinstall the two bearings and the bearing seat in the reverse order of the above, and install the coupling and the motor.

[0033] The specific implementation process is as follows:

[0034] The fan applicable to this solution must have bearings and bearing seats that can be removed from the motor side. Figure 1 As shown, the impeller side bearing is large, the motor side bearing is small, and both bearings can be removed from the motor side.

[0035] The bearing seat mounting surface needs to be drilled with a magnet drill in advance to process M20 threaded holes for easy installation of two fixtures. Leave a space for the bearing seat between the installation position of the motor-side fixture and the motor-side bearing seat, such as Figure 7 The installation position of the impeller side fixed tooling is as shown in Figure 4 As shown, in actual operation, some fan impellers are relatively close to the bearing seat, and the fixing fixture cannot be directly installed in place. Therefore, the impeller side bearing seat must be displaced first before the impeller side fixing fixture 4 can be installed.

[0036] The fixture is designed as a three-piece design, which can be easily placed on the fan main shaft, and is connected by two M20 bolts at the top and bottom. Figure 2 As shown. When installing the fixture, first place the two lower pieces under the spindle, fix them to the fan base with M20 bolts, then install the upper piece, and connect it to the two lower pieces with two M20 bolts. The center height of the inner holes of the two fixtures is 2mm higher than the center height of the spindle. The purpose is to fix the spindle while raising the spindle by 2mm, which is conducive to moving the bearing seat. Therefore, before installing the fixture, loosen the bearing seat mounting bolts first to leave 2mm of lifting space.

[0037] Since the motor side bearing is a fixed end, the motor side bearing seat needs to be marked before removal to ensure that it is reinstalled to its original position. The specific construction steps are as follows:

[0038] Loosen the two bearing seat mounting bolts, leaving a 2mm lifting space, and install the motor side fixing tool 3. After installation, the fan status is as follows: Figure 3 In this process, the fan main shaft is fixed by the motor side fixing fixture 3 and two bearing seats.

[0039] Remove the upper cover of the impeller side bearing seat 2, separate the bearing and the main shaft, and move the bearing seat to a certain position on the motor side. During this process, the fan main shaft is fixed by the motor side fixing tool 3 and the motor side bearing seat 1.

[0040] Install the impeller side fixing tool 4 in place. At this time, the fan status is as follows: Figure 5 shown.

[0041] If the fan impeller side bearing seat 2 is far enough from the casing to install the fixing fixture, directly install the impeller side fixing fixture 4. Figure 4 shown.

[0042] Remove the motor side fixture 3 and move the impeller side bearing together with the lower bearing seat to the motor side bearing seat. In this process, the main shaft is fixed by the impeller side fixture 4 and the motor side bearing seat 1. Figure 6 shown.

[0043] Install the motor side fixing tool 3. The fan status is as follows: Figure 7 shown.

[0044] Remove the motor and coupling, remove the two bearings and bearing seats. In this process, the main shaft is fixed by the motor side fixing fixture 3 and the motor side fixing fixture 4. At this time, the fan status is as follows: Figure 8 shown.

[0045] The process of reinstalling the two bearings and the bearing seats is the opposite of the above process.

[0046] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A method for online replacement of fan bearings, characterized in that: The method comprises the following steps: Step 1: First remove the fan motor and the coupling on the fan main shaft, and install the impeller side fixing tooling. Step 2: Remove the upper cover of the impeller side bearing seat, separate the bearing from the main shaft, move it to the side of the motor side bearing, and install the motor side fixing tooling. Step 3: Then remove the two bearings and the bearing seat, reinstall the two bearings and the bearing seat in the reverse order of the above, and install the coupling and the motor.

2. The method for online replacement of fan bearings according to claim 2, characterized in that: The fixed fixture is designed as a three-body type, which is conveniently placed on the main shaft of the fan. The upper and lower parts are connected by two M20 bolts. When installing the fixed fixture, first place the two lower pieces under the main shaft, fix them to the fan base with M20 bolts, and then install the upper piece, and connect it with the two lower pieces with two M20 bolts. The center height of the inner holes of the two fixed fixtures is 2mm higher than the center of the main shaft.

3. The method for online replacement of fan bearings according to claim 3, characterized in that: Step 2 is as follows: Loosen the two bearing seat mounting bolts, leave a 2 mm lifting space, and install the motor side fixing tool (3). In this process, the fan main shaft is fixed by the motor side fixing tool 3 and the two bearing seats.

4. The method for online replacement of fan bearings according to claim 3, characterized in that: In step 3, the upper cover of the impeller side bearing seat (2) is removed, the bearing and the main shaft are separated, and the bearing seat is moved to a certain position toward the motor side. During this process, the fan main shaft is fixed by the motor side fixing tool (3) and the motor side bearing seat (1).

5. The method for online replacement of fan bearings according to claim 2, characterized in that: In the method, the center height of the inner hole is 2 mm higher than the center of the main shaft, the diameter of the inner hole is the same as the diameter of the main shaft at the corresponding position, the two bearing seats of the fan are split bearing seats, the bearings and the bearing seats are removed from the motor side, and the bolt holes for installing the tooling are processed on the fan base.

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