MAINSHAFT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No.

62/189,836, filed July 8, 2015, the content of which is incorporated herein by reference.

BACKGROUND

[0002] The present invention relates to bearings, and more specifically to bearings used for supporting a mainshaft of a wind turbine.

[0003] Fig. 1 illustrates a long-standing (e.g., conventional) wind turbine drive train configuration 10 including a three-point mounting system 12. Specifically, the wind turbine drive train configuration 10 supports turbine blades 15 coupled to a nosecone 20, which in turn, is coupled to a wind turbine mainshaft 25 on three points of support. A first support is an upwind pillowblock 30 that normally contains a two-row spherical roller bearing 32 and is attached to a bedplate 35. Second and third supports are downwind and are two attachment points 40, 45 (e.g., torque arms) that are attached to the bedplate 35. Each torque arm 40, 45 is positioned on a side of a gearbox 50.

[0004] Fig. 2 illustrates a four-point mounting system 55 of another conventional wind turbine drive train configuration 10'. The four-point mounting system 55 supports the mainshaft 25 upwind and downwind on two pillowblocks 30. Each pillowblock 30 contains the two-row spherical roller bearing 32. Combined, there are four-supporting bearing rows in a four-point mounting.

[0005] In service, it often becomes necessary to perform maintenance and to replace the spherical roller bearing 32 in at least one of the pillowblocks 30. In the current environment, this replacement requires that a crane be brought on site to assist in the removal of the turbine blades 15 and the nosecone 20, and then to lower the rest of the drivetrain to ground level where the spherical roller bearing 32 can be changed out.

SUMMARY

[0006] It would be preferred if changing-out the pillowblock bearing could be completed up-tower without bringing a crane on sight. This invention describes a new type of split, two- row tapered roller bearing and pillowblock assembly which makes it possible to change out an existing mainshaft and pillowblock bearing assembly without need for a crane. The split pillowblock and tapered roller bearing races and roller-sets are split into at least two arcs (approximately 180 degree arcs) that can be installed around the mainshaft without having to disconnect it from the rest of the wind turbine. A double row tapered roller bearing inside the pillowblock housing is envisioned as a preferred design because it can be preloaded to optimize load zones in both rows for improving bearing life and controlling the radial and axial motion of the rotor assembly.

[0007] The general method that is envisioned for changing out of a pillowblock bearing assembly is as follows: (1) Loosen the existing pillowblock from the wind turbine bedplate by loosening the bolts on the feet of the existing pillowblock. (2) Lift the mainshaft and support it with steady-rests. (3) Cut off the existing pillowblock and bearing assembly. (4) Recondition the bearing seat as much as practical. (5) Measure the bearing seat diameter for optimizing the amount of internal clearance built into the replacement bearing prior to its installation on the mainshaft. (6) Install the split pillowblock and bearing assembly. (7) Secure onto the bedplate.

[0008] In one aspect, the invention provides a pillowblock and bearing assembly for a mainshaft of a wind turbine. The assembly is configured to allow installation on the mainshaft without removal of turbine blades, a nosecone, or a gearbox from the mainshaft. The assembly includes a two-piece pillowblock having first and second halves configured to be installed and connected together around the mainshaft. The two-piece pillowblock is supported by a bedplate of the wind turbine. The assembly also includes a two-piece inner race ring having first and second halves configured to be installed and connected together on the mainshaft. Each half of the two-piece inner race ring defines two raceways for supporting rolling elements in a two-row orientation. The assembly further includes a first two-piece outer race ring having first and second halves configured to be installed around the mainshaft. Each half of the first two-piece outer race ring defines a raceway for supporting a first row of the two-rows of rolling elements. The assembly also includes a second two-piece outer race ring having first and second halves configured to be installed around the mainshaft. Each half of the second two-piece outer race ring defines a raceway for supporting a second row of the two-rows of rolling elements. [0009] In another aspect, the invention provides a method of replacing a mainshaft pillowblock and bearing assembly of a wind turbine having a mainshaft and a bedplate. The method includes unsecuring an existing pillowblock and bearing assembly from the bedplate of the wind turbine, cutting the existing pillowblock and bearing assembly off the mainshaft to remove the existing pillowblock and bearing assembly from around the mainshaft, installing a split pillowblock and bearing assembly onto the mainshaft, and securing the installed split pillowblock and bearing assembly to the bedplate.

[0010] In yet another aspect, the invention provides a pillowblock and bearing assembly for a mainshaft of a wind turbine. The assembly is configured to allow installation on the mainshaft without removal of turbine blades, a nosecone, or a gearbox from the mainshaft. The assembly includes a multi-piece pillowblock having at least two pieces configured to be installed and connected together around the mainshaft. The multi-piece pillowblock being supported by a bedplate of the wind turbine. The assembly also includes a multi-piece inner race ring having at least two pieces configured to be installed and connected together on the mainshaft. Each piece of the multi-piece inner race ring defines two raceways for supporting rolling elements in a two-row orientation. The assembly further includes a first, multi-piece outer race ring having at least two pieces configured to be installed around the mainshaft. Each piece of the first, multi-piece outer race ring defines a raceway for supporting a first row of the two-rows of rolling elements. The assembly also includes a second, multi-piece outer race ring having at least two pieces configured to be installed around the mainshaft. Each piece of the second, multi-piece outer race ring defines a raceway for supporting a second row of the two-rows of rolling elements.

[0011] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Fig. 1 illustrates a conventional three-point mounting arrangement for a wind turbine mainshaft.

[0013] Fig. 2 illustrates a conventional four-point mounting arrangement for a wind turbine mainshaft. [0014] Fig. 3 is a perspective view of a first embodiment of a split pillowblock and bearing assembly embodying the present invention and configured to rotatably support a wind turbine mainshaft.

[0015] Fig. 4 is an exploded view of the split pillowblock and bearing assembly of Fig. 3.

[0016] Fig. 5 is a partial cross sectional view taken along 5— 5 of Fig. 3.

[0017] Fig. 6 is a partial cross sectional view taken along 5— 5 of Fig. 3 illustrating a split line of an inner race ring assembly relative to contact portions of first and second series of rolling elements of the split pillowblock and bearing assembly.

[0018] Fig. 7 is an exploded view of a portion of the split pillowblock and bearing assembly of Fig. 3 illustrating split clamping bands securing the inner race ring assembly to the mainshaft.

[0019] Fig. 8 is an assembled perspective view of the portion of the split pillowblock and bearing assembly of Fig. 7.

[0020] Fig. 9 illustrates a second embodiment of a split pillowblock and bearing assembly embodying the present invention and configured to rotatably support the wind turbine mainshaft.

[0021] Fig. 10A illustrates an anti-precession mechanism according to an embodiment including a key positioned between an inner race ring assembly and the mainshaft to inhibit relative movement between the inner race ring assembly and the mainshaft.

[0022] Fig. 10B illustrates an anti-precession mechanism according to another embodiment including a set screw positioned between the inner race ring assembly and the mainshaft to inhibit relative movement between the inner race ring assembly and the mainshaft.

[0023] Fig. 11 illustrates an anti-precession mechanism according to another embodiment including a split nut coupled between an inner race ring assembly and the mainshaft to inhibit relative movement between the inner race ring assembly and the mainshaft. [0024] Fig. 12 illustrates an anti -precession mechanism according to another embodiment including micro-splines positioned on an inner race ring assembly to inhibit relative movement between the inner race ring assembly and the mainshaft.

[0025] Fig. 13 illustrates an anti -precession mechanism according to another embodiment including a split collar coupled between an inner race ring assembly and the mainshaft to inhibit relative movement between the inner race ring assembly and the mainshaft.

DETAILED DESCRIPTION

[0026] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0027] Figs. 3-8 illustrate a split pillowblock and bearing assembly 100 coupled to the wind turbine mainshaft 25 about a bearing central axis 105. Pillowblocks (i.e., a lower pillowblock 110a and an upper pillowblock 110b) are fixable to the bedplate 35 of the wind turbine 10 by pillowblock bolts 112 (only one is shown in Fig. 4). In the illustrated embodiment, twelve pillowblock bolts 1 12 are used to fix the pillowblock 1 10 to the bedplate 35. The illustrated split pillowblock and bearing assembly 100 includes an inner race ring assembly 1 15 coupled to a bearing seat 116 (Figs. 3 and 7) of the mainshaft 25 for rotational movement with the mainshaft 25. The bearing seat 1 16 of the mainshaft 25 is the surface area of the mainshaft 25 that directly contacts the inner race ring assembly 1 15. The split pillowblock and bearing assembly 100 also includes an outer race ring assembly 120 (Figs. 4 and 5) fixed to the pillowblock 110 and positioned between the lower and upper pillowblocks 1 10a, 1 10b and the inner race ring assembly 1 15.

[0028] With reference to Figs. 4-8, the inner race ring assembly 115 defines a two-piece inner race ring having first and second inner ring halves 125, 130 coupled together by inner race bolts 132. Each inner ring half 125, 130 spans about 180 degrees in arc length and includes two inner raceways 135, 140 that are separated by a central flange 145 with first and second series of rolling elements 150, 155 (e.g., tapered rollers) seated within a

corresponding inner raceway 135, 140. This configuration is often referred to as a "tapered double inner" or TDI race. The central flange 145 is sized and configured to guide and separate the series of rolling elements 150, 155 about the bearing central axis 105. In addition, the first series of rolling elements 150 are positioned or spaced about the inner ring halves 125, 130, and therefore about the bearing central axis 105, by a first two-piece cage 156. The second series of rolling elements 155 are also positioned or spaced about the inner ring halves 125, 130, and therefore about the bearing central axis 105, by a second two-piece cage 158. The two pieces of each cage 156, 158 are rigidly jointed together by fasteners 159. In particular, cage links 162 (Fig. 6) span between the two pieces of each cage 156, 158 for the fasteners 159 to rigidly couple the two pieces of each cage 156, 158 together. In one embodiment, roller retainers may temporarily hold the rolling elements 150, 155 within the corresponding cage 156, 158 during assembly of the split pillowblock and bearing assembly 100, as described in detail below.

[0029] Once the inner ring halves 125, 130 are connected together, corresponding inner raceways 135, 140 of each inner ring half 125, 130 align to form a continuous inner raceway 135, 140 including split lines 160 (Figs. 3, 5, 6, and 8) at interfaces between the inner ring halves 125, 130. The illustrated split lines 160 are oriented at a non-parallel angle with respect to the bearing central axis 105 so that the first and second series of rolling elements 150, 155 are supported at all times by the inner raceways 135, 140. For example, the split lines 160 allow for contact portions 165 (i.e., ellipsoids) of the first and second series of rolling elements 150, 155 to contact the inner raceways 135, 140 as the contact portions 165 intersect or traverse the split lines 160. In other words, the contact portions 165 are never parallel to the split lines 160. In other embodiments, the inner race ring assembly 115 may have more than two halves or portions (e.g., the inner race ring assembly 1 15 may include three portions spanning about 120 degrees in arc length).

[0030] With continued reference to Figs. 4-8, the illustrated inner race ring assembly 115 is further coupled to the mainshaft 25 by clamping rings or bands 170 including first and second band halves 175, 180 coupled together by clamping band bolts 182. The illustrated clamping bands 170 are sized and configured to fix the inner ring halves 125, 130 relative to the mainshaft 25 to inhibit precession of the inner ring halves 125, 130 and the mainshaft 25. In other words, the clamping bands 170 provide an anti -precession mechanism 184 to inhibit relative movement between the inner race ring assembly 115 and the mainshaft 25. Each of the first and second band halves 175, 180 are received within grooves or recesses 185 of the inner ring halves 125, 130. In the illustrated embodiment, each inner raceway 135, 140 is positioned between the central flange 145 and one clamping band 170. The illustrated first and second band halves 175, 180 span less than 180 degrees in arc length such that split regions or gaps 190 are provided between the first and second band halves 175, 180 when the first and second band halves 175, 180 are coupled to the inner race ring assembly 1 15 (Fig. 8). In the illustrated embodiment, the split regions 190 are circumferentially offset from the split lines 160 of the inner ring halves 125, 130. In the illustrated embodiment, the split regions 190 are circumferentially offset about 90 degrees with respect to the split lines 160 of the inner ring halves 125, 130. In other embodiments, the clamping bands 170 may have more than two halves or portions (e.g., the clamping bands 170 may include three portions spanning less than 120 degrees in arc length). In further embodiments, the portions of the clamping bands 170 may abut (e.g., the first and second band halves 175, 180 span about 180 degrees in arc length to omit the gaps 190).

[0031] With reference to Figs. 3-5, the illustrated outer race ring assembly 120 includes a first two-piece outer race ring 195 having a first upper half 200 and a second lower half 205 separated from a second two-piece outer race ring 210 having a first upper half 215 and a second lower half 220 by a two-piece outer race spacer 225. The illustrated first two-piece outer race ring 195 also includes a first outer raceway 230 that aligns with the first inner raceway 135 of the inner race ring assembly 1 15, and the illustrated second two-piece outer race ring 210 also includes a second outer raceway 235 that aligns with the second inner raceway 140 of the inner race ring assembly 115. As such, the first series of rolling elements 150 are engageable between the first inner and outer raceways 135, 230, and the second series of rolling elements 155 are engageable between the second inner and outer raceways 140, 235.

[0032] The illustrated first two-piece outer race ring 195 is fixed to the upper and lower pillowblocks 1 10a, 1 10b by outer race bolts 240 received through pillowblock apertures 245 to threadably engage outer race apertures 250 located on an outer surface of the upper and lower halves 200, 205. Accordingly, the outer race bolts 240 inhibit precessing of the first two-piece outer race ring 195 relative to the pillowblock 110. In the illustrated embodiment, each upper and lower half 200, 205 of the first two-piece outer race ring 195 includes two outer race apertures 250 (e.g., two outer race bolts 240 fix each upper and lower half 200, 205 to the corresponding upper and lower pillowblocks 110a, 1 10b). In other embodiments, more or less than two outer race bolts 240 may fix the upper and lower halves 200, 205 to the pillowblock 1 10). In further embodiments, the first upper halves 200, 215 and one portion of the two-piece outer race spacer 225 may integrally form a first outer race ring, and the second lower halves 205, 220 and the other portion of the two-piece outer race spacer 225 may integrally form a second outer race ring.

[0033] Similar to the first two-piece outer race ring 195, the illustrated second two-piece outer race 210 is fixed to the upper and lower pillowblocks 110a, 110b by the outer race bolts 240 received through the pillowblock apertures 245 to threadably engage the outer race apertures 250.

[0034] In the illustrated embodiment, each outer race bolt 240 is located near a split line 255 of each outer race half 200, 205, 215, 220. The illustrated split lines 255 of each outer race half 200, 205, 215, 220 are generally shaped as concave or convex surfaces that abut each other. For example, a concave split line 255 of the first upper half 200 abuts a convex split line 255 of the first lower half 205.

[0035] With continued reference to Figs. 3-5, the split pillowblock and bearing assembly 100 also includes a front retainer assembly 260 and a rear retainer assembly 265 that are configured to inhibit axial movement of the inner race ring assembly 1 15 and the outer race ring assembly 120 along the bearing central axis 105. As shown in Fig. 5, the illustrated front retainer assembly 260 includes a two-piece front end plate 270, which abuts the pillowblock 110 and the first two-piece outer race ring 195, and is coupled to the pillowblock 1 10 by plate bolts 267. The plate bolts 267— in combination with the front and rear retainer assemblies 260, 276— also function to preload the inner race ring assembly 115, the outer race ring assembly 120, and the first and second series of rolling elements 150, 155 to improve the life of the split pillowblock and bearing assembly 100. In addition, pins 269 that extend from one piece of the two-piece front end plate 270 are engageable with the other piece of the front end plate 270 to align and connect both pieces together. The front retainer assembly 260 also includes a two-piece front labyrinth seal 275 that engages the front end plate 270, one of the clamping bands 170, and the inner ring halves 125, 130 of the inner race ring assembly 1 15. The front retainer assembly 260 further includes a two-piece front seal carrier plate 280 positioned between the front end plate 270 and the front labyrinth seal 275. The front seal carrier plate 280 supports front seals 285, which engage the front labyrinth seal 275. The illustrated rear retainer assembly 265 includes a two-piece rear labyrinth seal 290 that engages the pillowblock 110, one of the clamping bands 170, and the inner ring halves 125, 130 of the inner race ring assembly 115. The rear retainer assembly 265 also includes a two- piece rear seal carrier plate 295 positioned between the rear labyrinth seal 290 and the pillowblock 110. The rear seal carrier plate 295 supports rear seals 300, which engage the rear labyrinth seal 290. In other embodiments, at least one shim may be associated with at least one of the front and rear retainer assemblies 260, 265 to adjustably preload the split pillowblock and bearing assembly 100.

[0036] A method of replacing an existing pillowblock and bearing assembly (e.g., the pillowblock 30 and the two-row spherical roller bearing 32) on the mainshaft 25 with the illustrated split pillowblock and bearing assembly 100 is described in detail below. The method includes supporting and bracing the mainshaft 25 with, for example, hydraulic jack stands in preparation to remove the existing pillowblock and bearing assembly 30, 32 from the bedplate 35. The existing pillowblock and bearing assembly 30, 32 is unsecured from the bedplate 35 by removing bolts that couple the existing pillowblock and bearing assembly 30, 32 to the bedplate 35 (similar to the pillowblock bolts 112). The existing pillowblock and bearing assembly 30, 32 is then cut off (e.g., by using a gas-flamed torch, grinder, etc.) the mainshaft 25 to remove the existing pillowblock and bearing assembly 30, 32 from the mainshaft 25. The bearing seat 116 is reconditioned and a diameter of the mainshaft 25 is measured to ensure proper fit and clearance between the split pillowblock and bearing assembly 100 and the mainshaft 25 (e.g., optimize an amount of internal clearance built into the split pillowblock and bearing assembly 100).

[0037] Once the existing pillowblock and bearing assembly 30, 32 is removed from the mainshaft 25 and the mainshaft 25 reconditioned, the illustrated split pillowblock and bearing assembly 100 can then be installed onto the mainshaft 25. In particular, the first and second inner ring halves 125, 130 of the two-piece inner race ring assembly 115 are connected together around the mainshaft 25 by the inner race bolts 132, and the two-piece clamping bands 170 are clamped over the first and second inner ring halves 125, 130 by the clamping band bolts 182 to further secure the first and second inner ring halves 125, 130 on the mainshaft 25. The illustrated clamping bands 170 are also tightened around the first and second inner ring halves 125, 130 to aid in alignment of the first and second inner ring halves 125, 130 axially along the bearing central axis 105 (e.g., the clamping bands 170 aid in alignment of the inner raceways 135, 140). Furthermore, the clamping bands 170 provide a mechanical anti-rotating feature (i.e., the anti-precession mechanism 184) of the two-piece inner race ring assembly 1 15 relative to the mainshaft 25. For example, the split regions 190 allow the clamping bands 170 to be tightened as much as possible against the mainshaft 25 by tension created by tightening the clamping band bolts 182 to establish the gripping force that is needed to prevent precessing of the inner race ring assembly 115 on the mainshaft 25.

[0038] The method of installing the illustrated split pillowblock and bearing assembly 100 further includes coupling the outer race ring assembly 120, which is affixed to the pillowblock 1 10, to the inner race ring assembly 1 15 with the first and second series of rolling elements 150, 155 positioned therebetween. For example, the first and second two- piece retainers 156, 158 are coupled about the inner race ring assembly 115 before the mainshaft 25 can be lowered into the lower pillowblock 110a. The lower pillowblock 110a, the corresponding portion of the outer race ring assembly 120 (e.g., the second lower halves 205, 220 and one-piece of the two-piece outer race spacer 225), and the corresponding portions of the front and rear retainer assemblies 260, 265 (e.g., one-piece of the front end plate 270, one-piece of the front labyrinth seal 275, and one-piece of the rear labyrinth seal 290) are coupled together and positioned on the bedplate 35. As such, the mainshaft 25 can be lowered into the lower pillowblock 110a by the jack stand for the first and second series of rolling elements 150, 155 to engage the raceways 135, 140, 230, 235.

[0039] The upper pillowblock 110b, the corresponding portion of the outer race ring assembly 120 (e.g., the first upper halves 200, 215 and the other piece of the outer race spacer 225), and the corresponding portions of the front and rear retainer assemblies 260, 265 (e.g., the other piece of the front end plate 270, the other piece of the front labyrinth seal 275, and the other piece of the rear labyrinth real 290) are coupled together and positioned over the lower pillowblock 1 10a and the mainshaft 25. The pillowblock bolts 112 then secure the lower and upper pillowblock 1 10a, 1 10b to the bedplate 35. At this point, the plate bolts 267 can be tightened to preload the split pillowblock and bearing assembly 100 to withstand loading from wind thrust and induced thrust from each series of rolling elements 150, 155. Alternatively, the front retainer assembly 260 may be assembled by bolts 267 to the pillowblock 110 after the mainshaft 25 is supported by the lower pillowblock 1 10.

Accordingly, the method of installing the illustrated split pillowblock and bearing assembly 100 can be carried out up-tower without the use of a crane to disassemble the components (e.g., the blades 15 and nosecone 20) of the wind turbine 10.

[0040] In another embodiment, a method of replacing an existing pillowblock and bearing assembly 30, 32 on the mainshaft 25 with the illustrated split pillowblock and bearing assembly 100 generally includes assembling the lower pillowblock 110a and lower portions of the outer and inner race ring assemblies 1 15, 120 together, installing the reconditioned mainshaft 25 onto the lower pillowblock 110a and the lower portions of the outer and inner race ring assemblies 1 15, 120, and then assembling the upper pillowblock 1 10b and upper portions of the outer and inner race ring assemblies 115, 120 onto the mainshaft 25.

[0041] In this embodiment, the lower halves 205, 220 of the outer race ring assembly 120 and one of the outer race spacers 225 are coupled to the lower pillowblock 1 10a. The lower portion of the inner race ring assembly 120 can be assembled by coupling the lower inner ring half 130, the two lower portions of the cages 156, 158, and the rolling elements 150, 155 together, for example, by plastic cable ties. Utilizing the plastic cable ties maintains the rolling elements 150, 155 between the lower inner ring half 130 and the portions of the cages 156, 158 for the lower portion of the inner race ring assembly 120 to be assembled on the lower pillowblock 110a. One half of the front and rear retainer assemblies 260, 265 are also coupled to the lower pillowblock 1 10a. In another embodiment, one half of the front and rear retainer assemblies 260, 265 are coupled to the lower pillowblock 110a before the lower portion of the inner race ring assembly 120 is installed onto the lower pillowblock 1 10a. Once the lower portion of the inner race ring assembly 120 is installed onto the lower pillowblock 110a, the plastic cable ties are removed. As such, assembly of one half of the pillowblock and bearing assembly 100 is now completed.

[0042] The reconditioned mainshaft 25 is then lowered into the assembled lower pillowblock 1 10a. In one embodiment, the lower pillowblock 1 10a is secured to the bedplate 35 before the mainshaft 25 is lowered into the assembled lower pillowblock 110a. In another embodiment, the lower pillowblock 1 10a is secured to the bedplate 35 after the mainshaft 25 is lowered into the assembled lower pillowblock 1 10a.

[0043] A similar process of assembling the lower pillowblock 110a and the lower portions of the inner and outer race ring assemblies 1 15, 120 is performed on the upper pillowblock 1 10b and the upper portions of the inner and outer race ring assemblies 1 15, 120. In particular, the upper portion of the inner race ring assembly 120 can be assembled by coupling the upper inner ring half 135, the two upper portions of the cages 156, 158, and the rolling elements 150, 155 together by plastic cable ties. The upper portion of the inner race ring assembly 120 is then installed over the mainshaft 25 and coupled to the lower portion of the inner race ring assembly 120. For example, the inner ring halves 125, 130 are fastened together by the inner race bolts 132, the clamping bands 170 secure the inner ring halves 125, 130 to the mainshaft 25, and the cages 156, 158 are fixed together by the fasteners 159 with the plastic cable ties being removed before the upper ring half 130 is fixedly secured to the mainshaft 25. Thereafter, the other halves of the front and rear retainer assemblies 260, 265 are coupled to the halves of the front and rear retainer assemblies 260, 265 that are coupled to the lower pillowblock 110a. In other embodiments, the front and rear retainer assemblies 260, 265 may be assembled before the upper portion of the inner race ring assembly 120 is installed over the mainshaft 25. The upper halves 200, 215 of the outer race ring assembly 120 and the other outer race spacer 225 are coupled to the upper pillowblock 110b so that the upper pillowblock 110b can be secured to the lower pillowblock 110a, and ultimately, secured to the bedplate 35. In other embodiments, the upper halves 200, 215 of the outer race ring assembly 120 and the other outer race spacer 225 may be coupled to the inner race ring assembly 115 before the upper pillowblock 110b is secured to the lower pillowblock 110a.

[0044] Fig. 9 illustrates another embodiment of a split pillowblock and bearing assembly 400, with like components and features relative to the split pillowblock and bearing assembly 100 being shown with like reference numbers incremented by 300. For mainshaft applications in which more gripping force between an inner race ring assembly 415 and the mainshaft 25 is required, the central flange 145 may be omitted and replaced with a third clamping band 470c positioned between clamping bands 470a, 470b. By removing the central flange 145, a flat surface is provided between first and second series of rolling elements 450, 455 for a groove 417 to be formed therein that receives the third clamping band 470c. In replacing the central flange 145, a first outer ring flange 445a is formed on a first outer race ring 495 and a second outer ring flange 445b is formed on a second outer race ring 510. Similar to the central flange 145, the outer ring flanges 445a, 445b guide the first and second series of rolling elements 450, 455 about the rotational axis. Repositioning the flanges onto the outer race rings 495, 510 simplifies the inner race ring assembly 415 by eliminating the central flange 145 and reduces the potential for inner race distortion after splitting the inner race ring assembly 415 into two or more arcs. In other embodiments, the inner race ring assembly 415 may include the central flange 145 having the groove 417 formed therein that receives the third clamping band 470c. In further embodiments, the split pillowblock and bearing assembly 400 may include more than three clamping bands.

[0045] Figs. 10A and 10B illustrate another embodiment of an anti-precession mechanism 584, with like components and features relative to the split pillowblock and bearing assembly 100 being shown with like reference numbers incremented by 400. In one embodiment, the anti -precession mechanism 584 includes a key 586 that engages an inner race ring assembly 515 and the mainshaft 25 (Fig. 10A). In another embodiment, the anti- precession mechanism 584 includes a set screw 588 that is received through the inner race ring assembly 515 to engage the mainshaft 25 (Fig. 10B).

[0046] Fig. 1 1 illustrates another embodiment of an anti-precession mechanism 684, with like components and features relative to the split pillowblock and bearing assembly 100 being shown with like reference numbers incremented by 500. The anti-precession mechanism 684 includes a nut 690 having a slot 692 that threadably engages the mainshaft 25. A first locking bolt 694 threadably engages the nut 690 so that the first locking bolt 694 engages the nut 690 on both sides of the slot 692. The first locking bolt 694 is tightened to pinch the threads of the nut 690 and the mainshaft 25 together (e.g., the slot 692 decreases in width). In other embodiments, the first locking bolt 694 may increase the width of the slot 692 to pinch the threads of the nut 690 and the mainshaft 25 together. With the threads pinched together, the nut 690 is fixed in position relative to the mainshaft 25. A second locking bolt 696 also threadably engages the nut 690 to extend through the nut 690 and to be located within a slot or aperture 698 near a clamping band 670 of an inner race ring assembly 615. With the second locking bolt 696 positioned within the slot 698, the inner race ring assembly 615 is inhibited from rotating relative to the mainshaft 25 (e.g., by engagement between the second locking bolt 696 and the slot 698). In operation, the second locking bolt 696 may be positioned in the slot 698, and then the first locking bolt 694 may lock the nut 690 relative to the mainshaft 25.

[0047] Fig. 12 illustrates another embodiment of an anti-precession mechanism 784, with like components and features relative to the split pillowblock and bearing assembly 100 being shown with like reference numbers incremented by 600. The anti-precession mechanism 784 includes micro-splines 702 formed on an inner diameter of an inner race ring assembly 715. In the illustrated embodiment, the micro-splines 702 are formed on discrete portions of the inner race ring assembly 715. In other embodiments, the micro-splines 702 may be formed continuously on the inner diameter of the inner race ring assembly 715. The micro-splines 702 create a fitted surface still operating in the elastic range so that the circumferential surface at the interface between the inner race ring assembly 715 and the mainshaft 25 contains an elastic strain pattern ranging between a minimum and maximum value depending upon whether the shaft surface is under a micro groove (min strain) or a micro-spline (max strain).

[0048] Fig. 13 illustrates another embodiment of an anti-precession mechanism 884, with like components and features relative to the split pillowblock and bearing assembly 100 being shown with like reference numbers incremented by 700. The anti-precession mechanism 884 includes a nut 806 threadably engaging the mainshaft 25 with a first locking bolt 807 threadably engaging the nut 806 to be partially positioned within a slot 809 near a clamping band 870 of an inner race ring assembly 815. The nut 806 is also fixedly attached to the mainshaft 25 by a second locking bolt 811 engaging the nut 806 and a two-piece split collar 813. The split collar 813 is fixedly attached to the mainshaft 25 by an interference fit or other know methods at a location of lesser mainshaft stress (e.g., downwind of the inner race ring assembly 815). Thus, engagement between the slot 809 and the first locking bolt 807 inhibits the inner race ring assembly 815 from rotating relative to the mainshaft 25.

[0049] In some embodiments, the anti-precession mechanisms 584, 684, 784, 884 may be used individually or in combination with the split pillowblock and bearing assemblies 100, 400.

[0050] Various changes are envisioned from the illustrated embodiments without deviating from the present invention. For example, while the components are shown and described as being generally equally split to define 180 degree arc lengths, the splits need not be even, and the term "half or "halves" used herein need not mean that the halves are equal in arc length, size, etc. In yet other embodiments, the split components can be split into more than two pieces (e.g., three, four, or more pieces).

[0051] Various features of the invention are set forth in the following claims.