A large wind turbine main shaft sliding bearing

Abstract

The present invention discloses a large-scale wind turbine main shaft sliding bearing, belonging to the field of wind power generation technology, comprising a wind turbine main shaft, a spherical tilting thrust pad, a thrust pad end cover, an arc cylindrical tilting pad, a tilting pad bearing outer ring seat, a disassembly sleeve, and a positioning oil pipe. The arc cylindrical tilting pad bears radial force, the arc cylindrical tilting pad and the tilting pad bearing outer ring seat are positioned by a positioning pipe, and the main oil inlet pipe is connected to the tilting pad bearing outer ring seat. When the arc cylindrical tilting pad is disassembled, the arc cylindrical tilting pad that is not to be disassembled is tightened with bolts, and a pad is pulled out by connecting the arc cylindrical tilting pad with bolts, and then replaced with a new pad. The present invention arranges the arc cylindrical tilting pad reasonably, and the maximum load passes through the center point; the arc cylindrical tilting pad is pre-tightened by a disc spring or a cylindrical spring to improve the bearing capacity of the bearing; the worn pad can be easily and quickly identified, and can be easily disassembled and replaced; the arc cylindrical tilting pad is wear-resistant, has a long service life, and is simple and convenient to manufacture.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a main shaft sliding bearing of a large wind power generator set. Background Art

[0002] Wind turbines operate outdoors year-round, subject to harsh operating conditions, large temperature and humidity fluctuations, and complex load conditions. Consequently, wind turbine bearings must possess excellent impact resistance, sealing, lubrication, long life, and high reliability. Wind turbine bearings are crucial supporting components of wind turbines, playing a crucial role in the lifespan, performance, and reliability of the entire unit. Wind turbine main shaft bearings are large and represent a significant cost.

[0003] The main shaft loads in a wind turbine primarily come from the gravity of the turbine blades and hub, the shaft's own weight, the support and thrust forces of the main shaft bearings, the inertial loads and aerodynamic loads exerted on the main shaft by wind passing through the blades and hub, and other factors. Therefore, the main shaft must withstand radial forces and axial forces generated by the wind. Furthermore, due to the unique operating environment of the wind turbine, sudden changes in wind speed can also generate axial shock. The inner ring of the main shaft bearing is mounted to the main shaft through an interference fit, while the outer ring is fixed to a dedicated support on the frame. The axial force is applied by the main shaft shoulder to the end face of the inner ring.

[0004] In a running bearing, only a portion of the rollers bear load simultaneously. This area is called the bearing's load zone. The load and operating clearance of the bearing both affect this zone. If the load zone is too small, the rollers are more likely to slip during operation.

[0005] The speed of the input shaft of a wind turbine gearbox is generally 10-30 rpm. Due to the relatively low speed, it is often difficult to form an oil film on the input shaft bearing, resulting in severe wear.

[0006] As wind turbine capacity and main shaft diameters continue to grow, and considering the cost-effectiveness of wind turbines, main shaft bearings are becoming increasingly expensive. Replacing rolling bearings with cylindrical plain bearings can significantly reduce costs, but cylindrical plain bearings are difficult to replace after wear. (Tilt pad radial plain bearings exhibit optimal stability when they have the smallest axis trajectory amplitude and a zero vortex center offset angle, minimizing vortex in the wind turbine main shaft.) Summary of the Invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a main shaft sliding bearing for a large wind turbine generator set.

[0008] The technical solution of the present invention is as follows: A large-scale wind turbine main shaft sliding bearing includes a wind turbine main shaft, a tilting pad radial sliding bearing, a spherical tilting thrust pad, a thrust pad end cover, an arc cylindrical tilting pad block, a tilting pad bearing outer ring seat, a disassembly sleeve, and a positioning oil pipe. The sliding bearing is sleeved on the wind turbine main shaft. The cylindrical surface of the tilting pad radial sliding bearing is provided with a plurality of arc cylindrical tilting pad blocks, and the outer side of the arc cylindrical tilting pad block is provided with a tilting pad bearing outer ring seat. The end face of the tilting pad radial sliding bearing is provided with a spherical tilting thrust pad, and the outer side of the spherical tilting thrust pad is provided with a thrust pad end cover. The overall back side of the spherical tilting thrust pad is spherical and can swing with the wind turbine main shaft to withstand axial thrust.

[0009] The arc cylindrical tilting pad bears radial force. The back of the arc cylindrical tilting pad is arc-shaped and can swing with the axis of the main shaft. The center of the arc cylindrical tilting pad is positioned by a positioning tube. The positioning tube is hollow and lubricating oil flows through the tube and is sealed with an O-ring. The arc cylindrical tilting pad and the tilting pad bearing outer ring seat are positioned by a positioning oil pipe. The main oil inlet pipe on the positioning tube is connected to the tilting pad bearing outer ring seat. The lubricating oil enters the arc cylindrical tilting pad through the main oil inlet pipe and the tilting pad bearing outer ring seat.

[0010] The tilting pad bearing outer ring seat is connected with the disassembly sleeve, and the friction surface of the arc cylindrical tilting pad block is provided with two symmetrical threaded holes. The two sides and both ends of the arc cylindrical tilting pad block are provided with threaded holes, and the thrust pad end cover has a hole. When disassembling the arc cylindrical tilting pad block, bolts are passed through the tilting pad bearing outer ring seat and connected with the threaded holes on the friction surface of the arc cylindrical tilting pad block that is not to be disassembled to tighten the arc cylindrical tilting pad block that is not to be disassembled. As an auxiliary, bolts are passed through the thrust pad end cover to connect with the threaded holes on the end face of the tilting pad block. After pulling out the disassembly sleeve, the bolts are used to connect with the threaded holes on the end face of the arc cylindrical tilting pad block to pull out an arc cylindrical tilting pad block, and then a new arc cylindrical tilting pad block is replaced, and it is pulled by using the threaded holes on the end face, and then the tightening bolts are used to pass through the tilting pad bearing outer ring seat and connect and position the replaced arc cylindrical tilting pad block, and finally the disassembly sleeve and the end cover are installed.

[0011] The arc cylindrical tilting pad of the tilting pad radial sliding bearing has two preload structures, one using a disc spring as a preload and the other using a cylindrical spring as a preload.

[0012] The "disc spring solution" is that there are two symmetrical threaded holes on the end face of the arc cylindrical tilting pad, there are two symmetrical threaded holes on the friction surface of the arc cylindrical tilting pad, there is a hole on the thrust pad end cover, and a cylindrical groove is provided on the arc cylindrical tilting pad. A spring bracket and a disc spring are provided in the groove. The spring bracket is arranged at the bottom of the groove, and a disc spring is provided in the spring bracket. A preload top cover is provided at the upper end of the disc spring, and the preload top cover is fixed on the arc cylindrical tilting pad. One side of the preload top cover is in contact with the outer ring seat of the tilting pad bearing. The positioning oil pipe passes through the preload top cover and the spring bracket from the center. When installing the arc cylindrical tilting pad, two bolts are used to pass through the outer ring seat of the tilting pad bearing to tighten the arc cylindrical tilting pad. The friction surface of the pad is parallel to the center line of the main shaft. After installation, the bolts are removed and screw plugs and washers are installed at the upper end of the screw holes.

[0013] In the "cylindrical spring solution," the arc-cylindrical tilting pad has two symmetrical cylindrical holes with threaded holes at the bottom. The tilting pad bearing outer ring seat also has two symmetrical cylindrical holes with threads at the top. The upper and lower cylindrical holes are concentric. A spring is mounted below the cylindrical hole, and a spring top block is mounted above it. The spring top block has a through-hole in its center. To install the arc-cylindrical tilting pad, two bolts are inserted through the tilting pad bearing outer ring seat to tighten the arc-cylindrical tilting pad. The bolts pass through the through-hole in the center of the spring top block and the cylindrical spring. The lower ends of the bolts are threaded into the arc-cylindrical tilting pad. The pad friction surface is parallel to the spindle centerline. After installation, the bolts are removed, and a screw plug and washer are installed in the through-hole in the center of the spring top block.

[0014] When the arc cylindrical tilting pad is replaced, the spring top block and the spring need to be removed in advance. The rest of the scheme is the same as the "disc spring scheme".

[0015] A runout measurement sensor is installed on one side of the thrust pad end cap, with its measuring end in contact with the cylindrical surface of the wind turbine main shaft. The runout measurement sensor measures the maximum wear of the arc-cylindrical tilting pad. By analyzing the load spectrum of the tilting pad radial sliding bearing, the pad with the most wear can be identified and replaced.

[0016] The number of the arc cylindrical tilting pads is 6 to 12, and the number of the spherical tilting thrust pads is 6 to 12.

[0017] Take four-point support as an example: let point A be the wind turbine, and F x ,F y ,F z ,M x ,M y ,M z 6 degrees of freedom force and torque, point B is the front bearing of the wind turbine main shaft, and there is F in the radial direction bx ,F by ,F bz 3 forces, Fbx and F by is the force generated by the dynamic and static pressure tilting pad radial plain bearing pad, and the resultant force is F bxy , F bz It is composed of dynamic and static pressure spherical tiltable thrust pads. Point D is the rear bearing of the wind turbine main shaft. There is F in the radial direction. dx ,F dy 2 forces, F dx ,F dy is the force generated by the dynamic and static pressure tilting pad radial sliding bearing pad, and the resultant force is F dxy Point C is the center of gravity of the wind turbine main shaft, which is the gravity G, F HZ is the Z-direction force, F HX is the X-direction force, F HY is the Y-direction force, M HX is the X-direction torque, M HY is the Y-direction torque;

[0018]

[0019] F bxy is the front bearing seat load, F dxy is the rear bearing seat load.

[0020]

[0021]

[0022] The equation for determining the number of pads of the arc cylindrical tilting pad is:

[0023]

[0024] Where n is the number of tiles; F r is the bearing radial load rating, F xy The direction of the force can be on the XY plane (the plane perpendicular to the axis), and h is the safety factor. n is the pressure of a bearing, F m is the maximum thrust of n single radial thrust pads, p is the working pressure of a single bearing pad, p h The allowable specific pressure of a single bearing shell;

[0025] Under the same working conditions, the minimum oil film thickness of the tilting pad radial sliding bearing with n pads is h mn ,h mn-1 The minimum oil film thickness of a tilting pad radial plain bearing with n-1 pads of the same diameter and width, h mn+1 The minimum oil film thickness of a tilting pad radial plain bearing with n+1 pads of the same diameter and width, h minis the maximum oil film thickness of the tilting pad; c is the difference between the pad arc radius and the journal radius, e is the eccentricity of the shaft in the bearing coordinate system, θ is the offset angle in the bearing coordinate system, is the angle measured from the negative direction of the Y axis (rad), is the fulcrum position angle of the i-th bearing (the angle from the positive direction of the Y axis to the bearing fulcrum along the rotation direction), R is the bearing arc radius, α i is the swing angle of the i-th bearing, F * It is the characteristic value of bearing capacity, which is related to the support offset ratio and aspect ratio of the pad.

[0026] When the number of tilting pads is 8;

[0027] F bxy The radial force vector of the tilting pad journal bearing of the front bearing seat is:

[0028] F ba ,F bb ,F bc ,F bd ,F be ,F bf ,F bg ,F bh is the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the front bearing seat;

[0029] F bxy =F ba +F bb +F bc +F bd +F be +F bf +F bg +F bh ;

[0030] F dxy The radial force vector of the tilting pad radial plain bearing of the rear bearing seat is:

[0031] F da ,F dd ,F dc ,F dd ,F de ,F df ,F dg ,F dh is the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the rear bearing seat;

[0032] F dxy =F da +F dd +F dc +F dd +F de +Fdf +F dg +F dh ;

[0033] F z1 and F z1 is the wind turbine turbine axial force vector:

[0034] F za ,F zb ,F zc ,F zd ,F ze ,F zf ,F zg ,F zh ,F zi ,F zj ,F zk ,F zl ,F zm ,F zn ,F zo ,F zp The thrust vector of a single axial thrust pad of the 16 pads of the front bearing seat;

[0035] F z1 =F za +F zb +F zc +F zd +F ze +F zf +F zg +F zh ;

[0036] F z2 =F zi +F zj +F zk +F zl +F zm +F zn +F zo +F zp .

[0037] The dynamic coupling equations of radial force and axial force of the front bearing seat of the wind turbine main shaft are as follows:

[0038]

[0039] M r and M p represents the mass matrix of the wind turbine main shaft system and the wind turbine main transmission system; F r and F P Represents the radial force vector of the wind turbine main shaft bearing and the axial force vector of the wind turbine main transmission system; C r and C Prepresents the damping matrix of the wind turbine main shaft system and the wind turbine main transmission system; K r and K p represents the stiffness matrix of the wind turbine main shaft system and the wind turbine main transmission system; X r and X p Represents the radial and axial displacement vectors of the wind turbine main shaft bearing;

[0040] Bearing radial stiffness K r (oil film stiffness and bearing stiffness) and bearing radial damping C r , K s Bearing body stiffness, K oil Oil film stiffness; C zc is the bearing body damping, C oil is the oil film damping;

[0041] K oil =K oilj +K oild ;K oilj is the static stiffness of the oil film, K oild is the oil film dynamic pressure stiffness;

[0042] C r =C zc +C oil ; C oil =C oilj +C oild ; C oilj is the oil film static pressure damping, C oild is the oil film dynamic pressure damping.

[0043] The arc cylindrical tilting pad includes a steel back and a copper alloy layer. The steel back is covered with a copper alloy and a wear-resistant, low-friction coefficient penetration layer. The copper alloy has suitable hardness, ductility and thermal conductivity. The penetration layer on the surface of the copper alloy layer serves as the friction surface of a low-speed, high-pressure and high-reliability sliding bearing. It adopts a negative pressure casting and infiltration process and the material is hard ceramic.

[0044] The manufacturing method of the arc cylindrical tilting pad is as follows: a circular ring is machined by a numerically controlled machine tool, a copper alloy friction layer is cast in the inner hole by a negative pressure casting process, and then the tilting pad is cut out of the circular ring.

[0045] The sliding bearing is connected to the hydraulic system via an oil inlet pipe and has a two-stage back-pressure valve, a high-pressure stop, and a low-pressure stop. These valves have two operating modes: Mode 1: When the wind turbine main shaft starts at low speed, the hydraulic system activates the high-pressure stop, raising the main shaft and increasing the oil pad thickness. At high speeds, the bearing generates dynamic pressure, which the hydraulic system's oil pressure has little effect on, so the hydraulic system is shut down at high speeds. The low-pressure stop is activated during periods of low wind speed, wind speed, and shutdown to reduce fretting wear on the bearings, which significantly impacts bearings. Mode 2: The hydraulic system has two pressure valves, a high-pressure stop, and a low-pressure stop. Floating static pressure (low-pressure stop pressure) is used when the main shaft starts at low speed, while operating static pressure (high-pressure stop pressure) is used when the main shaft is operating. The low-pressure stop pressure is less than the high-pressure stop pressure, while the high-pressure stop pressure is greater than or equal to the bearing's working dynamic pressure. Each bearing has a one-way check valve in front of the oil inlet pipe.

[0046] The present invention has a reasonable arrangement of the arc cylindrical tilting pad radial sliding bearing, and the maximum load passes through the center point; the arc cylindrical tilting pad is pre-tightened by a disc spring or a cylindrical spring to improve the bearing's load-bearing capacity; there is a large contact area between the pad and the outer ring seat to increase the bearing pad swing damping and increase the stability of the pad; the oil film on the arc cylindrical tilting pad can reduce low-speed resonance; the worn pad can be easily and quickly identified and can be conveniently disassembled and replaced; the arc cylindrical tilting pad radial sliding bearing is wear-resistant, has a long service life, and is simple and convenient to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic structural diagram of a disc spring solution for a front bearing of a wind turbine main shaft according to the present invention;

[0048] Figure 2 This is a schematic structural diagram of a cylindrical spring solution for a front bearing of a wind turbine main shaft according to the present invention;

[0049] Figure 3 This is a schematic structural diagram of the disc spring solution for the rear bearing of the wind turbine main shaft of the present invention;

[0050] Figure 4 This is a schematic structural diagram of the front bearing of the wind turbine main shaft of the present invention;

[0051] Figure 5 A partial enlarged view of the disc spring preloading solution of the present invention;

[0052] Figure 6 A partial enlarged view of the disc spring installation solution of the present invention;

[0053] Figure 7 A partial enlarged view of the cylindrical spring preloading solution of the present invention;

[0054] Figure 8 A partial enlarged view of the cylindrical spring installation solution of the present invention;

[0055] Figure 9 It is a structural diagram of the arc cylindrical tilting pad;

[0056] Figure 10 It is a structural diagram of the arc cylindrical tilting pad;

[0057] Figure 11 Schematic diagram of 8 spherical tiltable thrust pads;

[0058] Figure 12 Schematic diagram of 10 spherical tiltable thrust pads;

[0059] Figure 13 It is the cross-sectional structure of the spherical tiltable thrust pad;

[0060] Figure 14 Schematic diagram of force analysis of a wind turbine main shaft system with a four-point support structure;

[0061] Figure 15 This is a schematic diagram of the force analysis of the front bearing seat of the wind turbine main shaft system with a four-point support structure;

[0062] Figure 16 This is a schematic diagram of the force analysis of the front bearing seat of the wind turbine main shaft system with a four-point support structure;

[0063] Figure 17 Schematic diagram of the force analysis of the arc cylindrical tilting pad of the wind turbine main shaft system with four-point support structure;

[0064] Figure 18 Schematic diagram of carburizing and crushing of arc cylindrical tilting pad;

[0065] Figure 19 Schematic diagram of cutting and manufacturing of arc cylindrical tilting pads;

[0066] In the figure: 1-wind turbine main shaft, 2-arc cylindrical tilting pad, 3-disassembly sleeve, 4-tilt pad bearing outer ring seat, 5-positioning oil pipe, 6-spherical tilting thrust pad, 7-thrust pad end cover, 8-O-ring, 9-runout measurement sensor, 10-tilt pad radial sliding bearing, 11-spring bracket, 12-disc spring, 13-preload top cover, 14-screw plug, 15-spring top block, 16-cylindrical spring, 17-steel back, 18-copper alloy layer, 19-negative pressure penetration layer, 20-tensioning bolt, 21-main oil inlet pipe, 22-oil inlet pipe, 23-oil drain pipe, 24-seal, 25-bolt, 26-seal ring, 27-cutting line, 28-front bearing seat of wind turbine main shaft, 29-rear bearing seat of wind turbine main shaft. DETAILED DESCRIPTION

[0067] The present invention will be further described below with reference to the accompanying drawings.

[0068] like Figure 1-8 Shown and Figure 11-13As shown, a large-scale wind turbine main shaft sliding bearing includes a wind turbine main shaft 1, a tilting pad radial sliding bearing 10, a spherical tilting thrust pad 6, a thrust pad end cover 7, an arc cylindrical tilting pad 2, a tilting pad bearing outer ring seat 4, a disassembly sleeve 3, and a positioning oil pipe 5. The tilting pad radial sliding bearing 10 is sleeved on the wind turbine main shaft 1. The cylindrical surface of the tilting pad radial sliding bearing 10 is provided with a plurality of arc cylindrical tilting pads 2, the number of arc cylindrical tilting pads 2 is 6 to 12, the outer side of the arc cylindrical tilting pad 2 is provided with a tilting pad bearing outer ring seat 4 and a disassembly sleeve 3, the two end surfaces of the tilting pad radial sliding bearing 10 are provided with spherical tilting thrust pads 6, the number of spherical tilting thrust pads 6 is 6 to 12, the outer side of the spherical tilting thrust pad 6 is provided with a thrust pad end cover 7, and the overall back surface of the spherical tilting thrust pad 6 is spherical, which can swing with the wind turbine main shaft 1 and withstand axial thrust.

[0069] The arc cylindrical tilting pad 2 bears radial force. The back of the arc cylindrical tilting pad 2 is arc-shaped and can swing along the axis of the wind turbine main shaft 1. The center of the arc cylindrical tilting pad 2 is positioned by the positioning oil pipe 5. The positioning oil pipe 5 is hollow and made of high-strength alloy steel. Lubricating oil flows through the pipe and is sealed with an O-ring 8. The arc cylindrical tilting pad 2 and the tilting pad bearing outer ring seat 4 are positioned through the positioning oil pipe 5. The main oil inlet pipe 21 on the positioning oil pipe 5 is connected to the tilting pad bearing outer ring seat 4. The lubricating oil enters the arc cylindrical tilting pad 2 through the main oil inlet pipe 21 and the tilting pad bearing outer ring seat 4.

[0070] The arc cylindrical tilting pad 2 of the tilting pad radial sliding bearing has two preload structures, one using a disc spring as a preload and the other using a cylindrical spring as a preload.

[0071] The tilting pad bearing outer ring seat 4 is connected with the disassembly sleeve 3. There are two symmetrical threaded holes on the friction surface of the arc cylindrical tilting pad 2. Threaded holes are distributed on both sides and ends of the arc cylindrical tilting pad 2. There is a hole on the thrust pad end cover 7. When removing the arc cylindrical tilting pad 2, bolts are passed through the tilting pad bearing outer ring seat 4 to connect with the threaded holes on the friction surface of the arc cylindrical tilting pad 2 that is not removed to tighten the arc cylindrical tilting pad 2 that is not removed. As an auxiliary, bolts are passed through the thrust pad end cover 7 to connect with the threaded holes on the end face of the tilting pad 2. After pulling out the disassembly sleeve 3, the bolts are connected with the threaded holes on the end face of the arc cylindrical tilting pad 2 to pull out a new arc cylindrical tilting pad 2, and then the new arc cylindrical tilting pad 2 is replaced and pulled by the threaded holes on the end face. Then, the tightening bolts are passed through the tilting pad bearing outer ring seat 4 to connect and position the replaced arc cylindrical tilting pad 2, and finally the disassembly sleeve and end cover are installed.

[0072] For the “cylindrical spring preload structure”, when replacing the arc cylindrical tilting pad 2 , the cylindrical spring 16 and the spring top block 15 must be taken out first.

[0073] like Figure 5 、 6 As shown, the arc-shaped tilting pad 2 has two symmetrical threaded holes. The arc-shaped tilting pad 2 is provided with a groove, in which a spring bracket 11 and a disc spring 12 are located. The spring bracket 11 is set at the bottom of the groove, and the disc spring 12 is located in the spring bracket 11. The upper end of the disc spring 12 is provided with a preload cap 13. The preload cap 13 is fixed to the arc-shaped tilting pad 2. One side of the preload cap 13 contacts the tilting pad bearing outer ring seat 4. The positioning oil pipe 5 passes through the preload cap 13 and the spring bracket 11 from the center. When installing the arc-shaped tilting pad 2, two bolts are used to pass through the tilting pad bearing outer ring seat 4 to tighten the arc-shaped tilting pad 2. The friction surface of the pad is parallel to the centerline of the wind turbine main shaft 1. After installation, the bolts are removed and the screw plug 14 and the washer are installed at the upper end of the screw hole.

[0074] like Figure 7 、 8 As shown, the arc-cylindrical tilting pad 2 has two symmetrical cylindrical holes with threaded holes at the bottom. The tilting pad bearing outer ring seat also has two symmetrical cylindrical holes with threads at the top. The upper and lower cylindrical holes are concentric. A cylindrical spring 16 is installed between the lower end of the spring top block 15 and the threaded holes in the arc-cylindrical tilting pad 2. A through-hole is provided in the center of the spring top block 15. When installing the arc-cylindrical tilting pad 2, two bolts are inserted through the through-hole in the center of the tilting pad bearing outer ring seat 4 to tighten the arc-cylindrical tilting pad 2. The bolts pass through the through-hole in the center of the spring top block 15 and the cylindrical spring 16. The lower ends of the bolts are threadedly connected to the arc-cylindrical tilting pad 2. The friction surface of the pad is parallel to the centerline of the wind turbine main shaft 1. After installation, the bolts are removed, and the screw plug 14 and washer are installed in the through-hole in the center of the spring top block 15.

[0075] Basic design parameters of the arc cylindrical tilting pad 2:

[0076] Journal speed: N = 10 ~ 30r / min (wind turbine main shaft); (When used for ship stern shaft thrust bearings, the stern shaft speed N is generally less than 150r / min, and the hydraulic system uses a two-stage pressure valve; when N ≥ 150r / min, the hydraulic system uses a one-stage pressure valve, and the friction surface material is Babbitt alloy)

[0077] Number of bearings: n = 6 to 12;

[0078] Bearing design static pressure: p0; unit: N / m 2 ;

[0079] Bearing specific pressure: p; unit: N / m 2 ;

[0080] Bearing load: F xy ;Unit: N;

[0081] Load spectrum: F x , Fy , F z , M x , M y , M z Unit: N, Nm; Available in all directions, with a constant value (rated) in the same direction, but with a maximum value;

[0082] Aspect ratio: L / d = 0.6 to 1.2;

[0083] Bearing width: L, unit: m;

[0084] Bearing diameter: d, unit: m;

[0085] Bearing thickness: t p , unit: m;

[0086] Two-stage pressure valve: primary pressure and secondary pressure;

[0087] Preload: F yz , unit: N; take the pressure generated by disc spring + static oil pressure; or the elastic force of cylindrical spring; preload coefficient: m = 0.2 ~ 0.6;

[0088] Gap ratio: ψ≈0.001;

[0089] Pivot offset ratio: 0.5;

[0090] Load-bearing mode: arc cylindrical line contact type; the load direction passes through the tile support point;

[0091] Elastic fulcrum: rigidity;

[0092] Lubricating oil dynamic viscosity: η, unit: P a ·s;

[0093] Minimum oil film thickness: h mn , unit: m;

[0094] Limit oil film thickness: h min , unit: m;

[0095] Support stiffness: K (Hollowing beneath the bearing point increases the primary stiffness of the oil film, suppressing low-frequency vibrations and improving stability.) Damping characteristics: C (Hollowing beneath the bearing point significantly increases the primary damping of the oil film, suppressing vibrations and improving stability.) Bearing material: Carburized alloy steel (42CrMo or 20CrMnTi, etc.) + copper alloy + surface carburizing and coating with special materials (including ceramic hard spots, low-friction and highly wettable soft materials). The copper alloy has suitable hardness, ductility, and thermal conductivity, and the alloy steel is carburized to prevent bearing wear.

[0096] like Figure 14-17 As shown, take four-point support as an example:

[0097] Assume that point A is the wind turbine, and F x ,F y ,F z ,M x ,M y ,M z 6 degrees of freedom force and torque, point B is the front bearing of the wind turbine main shaft, and there is F in the radial direction bx ,F by ,F bz 3 forces, F bx and F by is the force generated by the dynamic and static pressure tilting pad radial plain bearing pad, and the resultant force is F bxy , F bz It is composed of dynamic and static pressure spherical tiltable thrust pads. Point D is the rear bearing of the wind turbine main shaft. There is F in the radial direction. dx ,F dy 2 forces, F dx ,F dy is the force generated by the dynamic and static pressure tilting pad radial sliding bearing pad, and the resultant force is F dxy Point C is the center of gravity of the wind turbine main shaft, which is the gravity G, F HZ is the Z-direction force, F HX is the X-direction force, F HY is the Y-direction force, M HX is the X-direction torque, M HY is the Y-direction torque.

[0098]

[0099] F bxy is the front bearing seat load, F dxy is the rear bearing seat load.

[0100]

[0101]

[0102] The equation for determining the number of pads in an arc cylindrical tilting pad is:

[0103]

[0104] n is the number of tiles; F r is the bearing radial load rating, F xy The direction of the force can be on the XY plane (the plane perpendicular to the axis), and h is the safety factor. n is the pressure of a bearing, F m is the maximum thrust of n single radial thrust pads. p is the working pressure of a single bearing pad, p h It is the allowable specific pressure of a single bearing shell.

[0105] Assume that under the same working conditions, the minimum oil film thickness of the tilting pad radial sliding bearing with n pads is h mn ,h mn-1 The minimum oil film thickness of a tilting pad radial plain bearing with n-1 pads of the same diameter and width, h mn+1 The minimum oil film thickness of a tilting pad radial plain bearing with n+1 pads of the same diameter and width, h min is the maximum oil film thickness of the tilting pad; c is the difference between the pad arc radius and the journal radius, e is the eccentricity of the shaft in the bearing coordinate system, θ is the offset angle in the bearing coordinate system, is the angle measured from the negative direction of the Y axis (rad), is the fulcrum position angle of the i-th bearing (the angle from the positive direction of the Y axis to the bearing fulcrum along the rotation direction), R is the bearing arc radius, α i is the swing angle of the i-th bearing, F * It is the characteristic value of bearing capacity, which is related to the support offset ratio and aspect ratio of the pad.

[0106] Set the number of tilting pads to 8;

[0107] F bxy The radial force vector of the tilting pad journal bearing of the front bearing seat is:

[0108] F ba ,F bb ,F bc ,F bd ,F be ,F bf ,F bg ,F bh is the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the front bearing seat;

[0109] F bxy =F ba +F bb +F bc +F bd +F be +F bf +F bg +F bh ;

[0110] F dxy The radial force vector of the tilting pad radial plain bearing of the rear bearing seat is:

[0111] F da ,F dd ,F dc ,F dd ,F de ,F df ,F dg ,F dhis the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the rear bearing seat;

[0112] F dxy =F da +F dd +F dc +F dd +F de +F df +F dg +F dh ;

[0113] F z1 and F z1 is the wind turbine turbine axial force vector:

[0114] F za ,F zb ,F zc ,F zd ,F ze ,F zf ,F zg ,F zh ,F zi ,F zj ,F zk ,F zl ,F zm ,F zn ,F zo ,F zp The thrust vector of a single axial thrust pad of the 16 pads of the front bearing seat;

[0115] F z1 =F za +F zb +F zc +F zd +F ze +F zf +F zg +F zh ;

[0116] F z2 =F zi +F zj +F zk +F zl +F zm +F zn +F zo +F zp ;

[0117] The wind turbine main shaft system has lateral vibration (i.e. radial vibration), longitudinal vibration and torsional vibration, among which lateral vibration and longitudinal vibration have an impact on the sliding bearing.

[0118] The dynamic coupling equations of radial force and axial force on the front bearing seat of the wind turbine main shaft are:

[0119]

[0120] M r and M p — represents the mass matrix of the wind turbine main shaft system and the wind turbine main transmission system; F r and F P — represents the radial force vector of the wind turbine main shaft bearing and the axial force vector of the wind turbine main transmission system; C r and C P — represents the damping matrix of the wind turbine main shaft system and the wind turbine main transmission system; K r and K p — represents the stiffness matrix of the wind turbine main shaft system and the wind turbine main transmission system; X r and X p —Represents the radial and axial displacement vectors of the wind turbine main shaft bearing.

[0121] Bearing radial stiffness K r (oil film stiffness and bearing stiffness) and bearing radial damping C r , K s Bearing body stiffness, K oil Oil film stiffness; C zc is the bearing body damping, C oil is the oil film damping;

[0122] K oil =K oilj +K oild ;K oilj is the static stiffness of the oil film, K oild is the oil film dynamic pressure stiffness; C r =C zc +C oil ; C oil =C oilj +C oild ; C oilj is the oil film static pressure damping, C oild The positioning oil pipe 5 is provided with a small leakage hole to lubricate the contact surface to produce an oil film and damping due to the oil film extrusion during operation, thereby reducing low-frequency vibration.

[0123] The effects of bearing stiffness (oil film stiffness and bearing body stiffness) and bearing damping (oil film damping and bearing body damping) are used to avoid low-speed resonance of dynamic and static pressure tilting pad radial and axial sliding bearings.

[0124] A runout measurement sensor 9 is provided on one side of the thrust shoe end cover 7. The measuring end of the runout measurement sensor 9 contacts the cylindrical surface of the wind turbine main shaft 1 to measure the runout value.

[0125] The measurement method of replacing the worn pads according to the detected runout value is as follows: Due to the changes in wind force, the axial position of the wind turbine main shaft is changing. Each pad of the tilting pad radial sliding bearing may be in a working state, and the wear of each pad is also uneven. There is always one pad with the largest wear. The maximum wear amount is obtained by the runout measurement sensor 9. The pad with the largest wear can be found by analyzing the load spectrum of the tilting pad radial sliding bearing. The maximum wear amount is obtained by the runout measurement sensor 9, and the pad to be replaced is determined.

[0126] like Figure 9 、 10 As shown in Figures 18 and 19, the sliding bearing of the present invention is a low-speed sliding bearing. The pad structure is a steel back 17 coated with a copper alloy and a wear-resistant, low-friction coefficient penetration layer. The copper alloy has suitable hardness, ductility, and thermal conductivity. The surface penetration layer is suitable as a friction surface of a low-speed, high-pressure, and high-reliability sliding bearing. The negative pressure casting process is used, and the material is a hard ceramic SiC, Ti3SiC2, TiC, B4C, Al2O3, SiO2, BN, Si3N4, etc. + Gr / Cu [hard ceramic hard points + low-friction coefficient and high-wettability soft material (such as graphite) + copper alloy] surface composite material. The manufacturing method of the arc cylindrical tilting pad 2 is: use a CNC machine tool to process a circular ring as shown in the figure, use a negative pressure casting process to cast a copper alloy friction layer in the inner hole, then cut out the tilting pad, and then process the final part according to the figure.

[0127] The sliding bearing is connected to the hydraulic system via an oil inlet pipe. The hydraulic system features a two-stage back-pressure valve: a high-pressure stop and a low-pressure stop. This valve has two operating modes. In Mode 1, when the wind turbine main shaft starts at low speed, the hydraulic system activates the high-pressure stop, raising the main shaft and increasing the oil pad thickness. At high speeds, the bearing generates dynamic pressure, which has little effect on the hydraulic system's oil pressure, so the hydraulic system is shut down at high speeds. The low-pressure stop is activated during periods of low wind speed, wind speed, and shutdown to reduce fretting wear on the bearings, which can significantly affect bearings. In Mode 2, the hydraulic system features a two-stage pressure valve: a high-pressure stop and a low-pressure stop. Floating static pressure (low-pressure stop pressure) is used when the main shaft starts at low speed, while operating static pressure (high-pressure stop pressure) is used during main shaft operation. Low-pressure stop pressure is less than high-pressure stop pressure, while high-pressure stop pressure is greater than or equal to the bearing's working dynamic pressure. Each bearing is equipped with a one-way check valve in front of the oil inlet pipe.

[0128] The sliding bearing can also be used in ship propulsion to bear the thrust of the stern shaft and radial forces in all directions; the bearing seat is connected to the stern shaft, and the stern shaft is further connected to a marine gearbox or a diesel engine.

Claims

1. A large-scale wind turbine main shaft sliding bearing, comprising a wind turbine main shaft (1), a tilting pad radial sliding bearing (10), a spherical tilting thrust pad (6), a thrust pad end cover (7), an arc cylindrical tilting pad block (2), a tilting pad bearing outer ring seat (4), a disassembly sleeve (3), and a positioning oil pipe (5), wherein the tilting pad radial sliding bearing (10) is sleeved on the wind turbine main shaft (1), and is characterized in that: The cylindrical surface of the tilting pad radial sliding bearing (10) is provided with a plurality of arc cylindrical tilting pad blocks (2), the outer side of the arc cylindrical tilting pad blocks (2) is provided with a tilting pad bearing outer ring seat (4) and a disassembly sleeve (3), the two end surfaces of the tilting pad radial sliding bearing (10) are provided with spherical tilting thrust pads (6), the outer side of the spherical tilting thrust pads (6) is provided with thrust pad end covers (7), the overall back surface of the spherical tilting thrust pads (6) is spherical, and can swing with the wind turbine main shaft (1) to withstand axial thrust, The arc cylindrical tilting pad (2) bears radial force. The back of the arc cylindrical tilting pad (2) is in an arc shape and can swing along with the axis of the wind turbine main shaft (1). The center of the arc cylindrical tilting pad (2) is positioned by a positioning oil pipe (5). The positioning oil pipe (5) is hollow. Lubricating oil flows through the pipe and is sealed with an O-ring (8). The arc cylindrical tilting pad (2) and the tilting pad bearing outer ring seat (4) are positioned through the positioning oil pipe (5). The main oil inlet pipe (21) on the positioning oil pipe (5) is connected to the tilting pad bearing outer ring seat (4). The lubricating oil enters the arc cylindrical tilting pad (2) through the main oil inlet pipe (21) and the tilting pad bearing outer ring seat (4). The tilting pad bearing outer ring seat (4) is connected to the disassembly sleeve (3), and the friction surface of the arc cylindrical tilting pad (2) is provided with two symmetrical threaded holes. The two sides and both ends of the arc cylindrical tilting pad (2) are provided with threaded holes. The thrust pad end cover (7) is provided with a hole. When the arc cylindrical tilting pad (2) is disassembled, a bolt is passed through the tilting pad bearing outer ring seat (4) and connected to the threaded hole on the friction surface of the arc cylindrical tilting pad (2) that is not to be disassembled. ) is tightened, and as an auxiliary, a bolt is used to pass through the thrust pad end cover (7) to connect the threaded hole on the end face of the tilting pad (2), and after pulling out the disassembly sleeve (3), a piece of arc cylindrical tilting pad (2) is pulled out by connecting with the threaded hole on the end face of the arc cylindrical tilting pad (2) with a bolt, and then a new arc cylindrical tilting pad (2) is replaced, and it is pulled by the threaded hole on the end face, and then a tightening bolt is used to pass through the tilting pad bearing outer ring seat (4) and connect and position the replaced arc cylindrical tilting pad (2).

2. A large-scale wind turbine main shaft sliding bearing according to claim 1, characterized in that: The arc cylindrical tilting pad (2) has two symmetrical threaded holes, and the arc cylindrical tilting pad (2) has a groove, and a spring bracket (11) and a disc spring (12) are arranged in the groove. The spring bracket (11) is arranged at the bottom of the groove, and the disc spring (12) is arranged in the spring bracket (11). The upper end of the disc spring (12) is provided with a preload cover (13), and the preload cover (13) is fixed on the arc cylindrical tilting pad (2). One side of the preload cover (13) contacts the outer ring seat (4) of the tilting pad bearing. The positioning oil pipe (5) passes through the preload cover (13) and the spring bracket (11) from the center. When installing the arc cylindrical tilting pad (2), two bolts are passed through the outer ring seat (4) of the tilting pad bearing to tighten the arc cylindrical tilting pad (2). The friction surface of the pad is parallel to the center line of the wind turbine main shaft (1). After installation, the bolts are removed and a screw plug (14) and a washer are installed at the upper end of the screw hole.

3. A large-scale wind turbine main shaft sliding bearing according to claim 1, characterized in that: The arc cylindrical tilting pad (2) is provided with two symmetrical threaded holes, the upper ends of the threaded holes are connected to a spring top block (15) through threads, a cylindrical spring (16) is provided between the lower end of the spring top block (15) and the threaded hole on the arc cylindrical tilting pad (2), and a through hole is provided at the center of the spring top block (15). When installing the arc cylindrical tilting pad (2), two bolts are passed through the tilting pad bearing outer ring seat (4) to tighten the arc cylindrical tilting pad (2), the bolts pass through the through hole in the center of the spring top block (15) and the cylindrical spring (16), the lower part of the bolts is threadedly connected to the arc cylindrical tilting pad (2), and the friction surface of the pad is parallel to the center line of the wind turbine main shaft (1). After installation, the bolts are removed, and a screw plug (14) and a washer are installed in the through hole in the center of the spring top block (15).

4. A large-scale wind turbine main shaft sliding bearing according to claim 1, characterized in that: A runout measurement sensor (9) is provided on one side of the thrust pad end cover (7), and a measuring end of the runout measurement sensor (9) contacts the cylindrical surface of the wind turbine main shaft (1). The maximum wear amount is obtained through the runout measurement sensor (9), and the pad with the largest wear is found by analyzing the load spectrum of the tilting pad radial sliding bearing, and the arc cylindrical tilting pad (2) to be replaced is determined.

5. The large wind turbine main shaft sliding bearing according to claim 1, characterized in that: The equation for determining the number of the arc cylindrical tilting pads (2) is: Where n is the number of tiles; F r is the bearing radial load rating, F xy The direction of the force is on the XY plane, h is the safety factor, F1···F n is the pressure of a bearing, F m is the maximum thrust of n single radial thrust pads, p is the working pressure of a single bearing pad, p h The allowable specific pressure of a single bearing shell; Under the same working conditions, the minimum oil film thickness of the tilting pad radial sliding bearing with n pads is h mn ,h mn-1 The minimum oil film thickness of a tilting pad radial plain bearing with n-1 pads of the same diameter and width, h mn+1 The minimum oil film thickness of a tilting pad radial plain bearing with n+1 pads of the same diameter and width, h min is the maximum oil film thickness of the tilting pad; c is the difference between the pad arc radius and the journal radius, e is the eccentricity of the shaft in the bearing coordinate system, θ is the offset angle in the bearing coordinate system, is the angle measured from the negative direction of the Y axis, is the support point angle of the i-th bearing, R is the bearing arc radius, α i is the swing angle of the i-th bearing, F * It is the characteristic value of bearing capacity, which is related to the support offset ratio and aspect ratio of the pad.

6. A large-scale wind turbine main shaft sliding bearing according to claim 5, characterized in that: The number of tilting pads is 8; F bxy The radial force vector of the tilting pad journal bearing of the front bearing seat is: F ba ,F bb ,F bc ,F bd ,F be ,F bf ,F bg ,F bh is the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the front bearing seat; F bxy =F ba +F bb +F bc +F bd +F be +F bf +F bg +F bh ; F dxy The radial force vector of the tilting pad radial plain bearing of the rear bearing seat is: F da ,F dd ,F dc ,F dd ,F de ,F df ,F dg ,F dh is the thrust vector of a single radial thrust pad of the 8 pads of the tilting pad radial plain bearing of the rear bearing seat; F dxy =F da +F dd +F dc +F dd +F de +F df +F dg +F dh ; F z1 and F z1 is the wind turbine turbine axial force vector: F za ,F zb ,F zc ,F zd ,F ze ,F zf ,F zg ,F zh ,F zi ,F zj ,F zk ,F zl ,F zm ,F zn ,F zo ,F zp The thrust vector of a single axial thrust pad of the 16 pads of the front bearing seat; F z1 =F za +F zb +F zc +F zd +F ze +F zf +F zg +F zh ; F z2 =F zi +F zj +F zk +F zl +F zm +F zn +F zo +F zp 。 7. A large wind turbine main shaft sliding bearing as claimed in claim 1, characterized in that: Point A is the wind turbine, and F x ,F y ,F z ,M x ,M y ,M z 6 degrees of freedom force and torque, point B is the front bearing of the wind turbine main shaft, and there is F in the radial direction bx ,F by ,F bz 3 forces, F bx and F by is the force generated by the dynamic and static pressure tilting pad radial plain bearing pad, and the resultant force is F bxy , F bz It is composed of dynamic and static pressure spherical tiltable thrust pads. Point D is the rear bearing of the wind turbine main shaft. There is F in the radial direction. dx ,F dy 2 forces, F dx ,F dy is the force generated by the dynamic and static pressure tilting pad radial sliding bearing pad, and the resultant force is F dxy Point C is the center of gravity of the wind turbine main shaft, which is the gravity G, F HZ is the Z-direction force, F HX is the X-direction force, F HY is the Y-direction force, M HX is the X-direction torque, M HY is the Y-direction torque; F bxy is the front bearing seat load, F dxy is the rear bearing seat load; 8. The large wind turbine main shaft sliding bearing according to claim 1, characterized in that: The dynamic coupling equations of radial force and axial force of the arc cylindrical tilting pad (2) are: M r and M p represents the mass matrix of the wind turbine main shaft system and the wind turbine main transmission system; F r and F P Represents the radial force vector of the wind turbine main shaft bearing and the axial force vector of the wind turbine main transmission system; C r and C P represents the damping matrix of the wind turbine main shaft system and the wind turbine main transmission system; K r and K p represents the stiffness matrix of the wind turbine main shaft system and the wind turbine main transmission system; X r and X p Represents the radial and axial displacement vectors of the wind turbine main shaft bearing; Bearing radial stiffness K r and bearing radial damping C r , K s Bearing body stiffness, K oil Oil film stiffness; C zc is the bearing body damping, C oil is the oil film damping; K oil =K oilj +K oild ;K oilj is the static stiffness of the oil film, K oild is the oil film dynamic pressure stiffness; C r =C zc +C oil ; C oil =C oilj +C oild ; C oilj is the oil film static pressure damping, C oild is the oil film dynamic pressure damping.

9. The large-scale wind turbine generator main shaft sliding bearing according to claim 1, characterized in that: The arc cylindrical tilting pad (2) comprises a steel back (17) and a copper alloy layer (18), the steel back (17) is coated with a copper alloy and a wear-resistant low friction coefficient penetration layer, the copper alloy has suitable hardness, ductility and thermal conductivity, the penetration layer on the surface of the copper alloy layer (18) serves as a friction surface of a low-speed, high-pressure and high-reliability sliding bearing, adopts a negative pressure casting and infiltration process, and the material is hard ceramic. The manufacturing method of the arc cylindrical tilting pad (2) is as follows: using a CNC machine tool to cut and process a circular ring, using a negative pressure casting and infiltration process to cast a copper alloy friction layer in the inner hole, and then cutting the circular ring to form a tilting pad; The sliding bearing is connected to the hydraulic system through the oil inlet pipe, which is equipped with a two-stage back pressure valve, a high-pressure block and a low-pressure block, and has two working modes. Working mode 1: When the wind turbine main shaft starts at low speed, the hydraulic system opens the high-pressure block, lifts the wind turbine main shaft, and increases the thickness of the oil pad; at high speed, the bearing generates dynamic pressure, and the oil pressure generated by the hydraulic system has little effect, so the hydraulic system is closed at high speed; the low-pressure block is opened when there is no wind, low wind speed, or shutdown to reduce the micro-wear of the bearing, which has a significant impact on the bearing; Working mode 2: There are two-stage pressure valves in the hydraulic system, a high-pressure block and a low-pressure block. Floating static pressure is used when the main shaft starts at low speed, and working static pressure is used when the main shaft is working. The low-pressure block pressure is < the high-pressure block pressure, and the high-pressure block pressure is ≥ the working dynamic pressure of the bearing. There is a one-way valve and a check valve in front of the oil inlet pipe of each bearing.

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