Low-runout drive pulley for spindle shaft applications using multiple bearing sets with radial clearance to the shaft

Abstract

A low-runout drive pulley using a spindle shaft application with multiple sets of bearings with radial clearance relative to the shaft. A belt drive pulley is used to support a protruding load with low runout provided by a spindle shaft with radial clearance relative to the supporting bearings. Further, an axial clamping load is provided by the multiple sets of bearings by using fasteners such as sleeves and shaft bolts that press axially against the inner races of the bearings with a clamping force. A low-runout belt drive pulley using a spindle shaft application with at least two sets of bearings with radial clearance relative to the shaft can be used in heavy equipment trucks, marine, industrial, and other systems that use protruding drive pulleys.

Description

[Background technology]

[0001] The present invention relates to a low runout drive pulley for spindle shaft applications using multiple sets of bearings with radial clearance to the shaft.

[0002] The present disclosure relates to a belt drive pulley with low axial runout for spindle shaft applications using multiple sets of bearings with radial clearance relative to the shaft, such as for heavy equipment trucks, marine, industrial, and other systems using protruding drive components. Industries using belts often require the use of belt pulleys to drive accessory components such as, but not limited to, mechanical fans.

[0003] In heavy equipment transportation applications, mechanical fans are required to cool and circulate air around the motor and surrounding components. This involves the application of a fan clutch, where the fan blades are often directly coupled at one end and allowed to slip at the other end, which is directly coupled to a pulley. When the engine or radiator temperature reaches a set point, the slip is reduced, or the clutch is fully engaged. When the fan clutch is fully engaged, the surrounding fan is driven directly by the drive pulley. This fan clutch mechanism overhangs the pulley, resulting in significant structure (sometimes over 8 kg) with inherent imbalance due to its size, which requires a sturdy structure to mount the fan and contain its internal mechanism. At high speeds, when added to the imbalance caused by wobble in the mounting surface assembly, the clutch imbalance force may be excessive for the supporting casting and bearings to structurally support. Because the clutch has inherent imbalance due to its internal structure, it may be necessary to minimize the additional imbalance of the pulley and fan. In some situations, the most efficient way to mount a fan clutch is directly to the pulley, using a nut that secures to the pulley's threaded hub. Unbalance caused by the clutch assembly at this hub is controlled by the runout of the adjacent surface in front of the pulley. The runout of this adjacent surface relative to the axis of rotation is called runout. Because this is the seating surface of the clutch nut, it is often called nut runout. While primarily applicable to mechanical fans, low runout drive pulleys also apply to mechanisms that seat on the drive pulley with large loads and imbalances and protrude beyond the belt. Early-generation fan bracket designs had low clutch weights and required runout at the mounting surface of 0.085 mm. As more complex clutch mechanisms accommodate larger weights, the mounting requirement is reduced to 0.035 mm. Newer generation clutch designs in some systems may require runout of 0.025 mm, or even less.

[0004] Belt-driven pulley systems are known in which the rotation and load are supported by one or two bearing raceways mounted on a bracket. When the pulley must also support loads overhanging the outside of the drive belt plane, a secondary raceway is required because a single row of bearings can tilt between the inner and outer races, resulting in uneven ball or roller contact, resulting in uneven grease film thickness and overheating damage. Integral bearings are used for economy due to the unsupported overhang in the pulley. Here, the inner shaft features an inner raceway machined directly into the outer diameter, accommodating two or more rows of bearings. At least one end of the shaft is press-fit directly into the pulley hub. This end typically also features a fan mounting. The outer raceway is typically press-fit into a surrounding mounting bracket. These cartridge bearings sometimes have one row of ball bearings and one row of roller bearings for precision motion and thrust load support. However, CN205089439U describes the use of double tapered roller bearings, i.e., double-row conical bearings, and a fan bracket shaft, connecting the fan directly to the pulley via the fan flange. In other applications, the hub is attached to the integral bearing shaft by a press fit, and the integral bearing's outer race is press-fit into the mounting bracket. The problem with these designs is that the space between the raceways is limited by the bearings. Due to the required bearing size, it is not economical for the distance between the raceways to be greater than 70 mm. Large bearing spans also pose difficulties, such as ensuring that bearings of this size have adequate lubrication of both raceways. In this example, more than two bearings may be used to support a larger shaft.

[0005] However, increasing the spacing of the support bearing rows may achieve a more precise rotational axis and reduce runout. Furthermore, press-fitting the bearings onto the shaft causes distortion of the surrounding fan mounting surface, which is detrimental to the runout of the mounting surface. Assembling other features for mounting the fan separately from the shaft is another degree of freedom that increases the magnitude of runout. Relaxing the runout requirements required for fan clutch installation has led some manufacturers to machine the mounting surface after pulley assembly. This requires investment in expensive cutting systems, and the resulting chips can adversely affect alignment datums or damage bearings, resulting in high runout measurements. While it is possible to sort to lower values ​​and accept a high reject rate, this is costly and may not be sustainable for the overall manufacturing environment.

[0006] In some embodiments, the present invention employs two bearing sets with at least one double-row bearing. Therefore, three to four rows of raceways are used to support the bearing shafts. These bearings may have outer races pressed into the support bracket. The distance between the two bearings is controlled via a sleeve compressed between the bearing's inner races. Both the inner race and spacer provide a clearance fit with a minimum 0.005 mm diameter clearance for shafts that are not press-fit into the bearings to allow manual assembly. The shaft is precision-ground to ensure that the clutch nut seat maintains very tight axial runout relative to the diameter of the rotating shaft. Therefore, the clutch mounting surface, threaded hub, and precision-ground shaft feature in a single piece, insensitive to assembly variations. This runout is not distorted by press-fit or other mounting assemblies, and the clutch fan is mounted directly to this shaft. The outermost bearing resists fan thrust motion by securing bracket material over the outer race or by utilizing clips. The shaft is held by flanges which are clamped to the shaft by screws and which apply a clamping load between the inner races of the two bearing sets via sleeves. The screw flange assembly provides even clamping and achieves the best possible shaft runout.

[0007] A potential benefit of the present invention is achieving very low runout at the assembly level for unsupported, protruding components that are mounted on pulleys and have high imbalance, such as cooling fans. The use of more than two bearing raceways may ideally provide more precise support for rotating shafts under high loads. In some embodiments, the distance between two bearing sets may be increased by utilizing a spacer that provides clamping for the two inner races of the bearing sets. Unsupported, protruding features (such as fan clutches) are mounted directly to the shaft, providing robust runout at the component level and not affected by subsequent press-fits or intermediate components in the assembly. A preferred embodiment eliminates the need to machine mounting surfaces after assembly, which increases costs and may introduce cutting fluids that can contaminate bearing grease and chips that can damage bearing seals.

[0008] In applications requiring high convection for cooling, a large fan may be mounted directly to the belt-driven pulley. This fan may be unsupported as long as the bearing design is robust and the mounting features have low axial runout relative to the pulley axis of rotation. The present invention may also allow the use of standard bearing assemblies instead of designing a new integrated bearing for a new application. The present invention can hold axial runout to micron-level tolerances for mounting the fan.

[0009] Additionally, the invention may have application in non-ICE motor cooling or industrial applications that require significant convection to cool the surrounding environment. The invention also reduces scrap compared to current methods of assembling parts into integral bearings by not requiring machining to improve mounting surface quality or to remove press-fit distortion in these assemblies.

[0010] Additionally or alternatively, in some embodiments, the low axial runout drive pulley system may include a mounting bracket, a first bearing assembly seated in the mounting bracket, a second bearing assembly seated in the mounting bracket, a sleeve disposed between the first bearing assembly and the second bearing assembly, a shaft disposed between the first bearing assembly and the second bearing assembly, and a clamp flange having a shaft bolt, the clamp flange configured and arranged to axially secure the shaft relative to the second bearing assembly, and may further include a pulley secured to the shaft.

[0011] In another embodiment, a low runout drive pulley system includes a mounting bracket, a first bearing assembly seated within the mounting bracket on a first shelf hard stop, a second bearing assembly seated within the mounting bracket, a sleeve disposed between the first bearing assembly and the second bearing assembly, a shaft rotatably disposed between the first bearing assembly and the second bearing assembly, the shaft having a machined shaft diameter and including a machined mounting surface, a threaded hub, and a clamp flange with a shaft bolt configured and arranged to axially secure the shaft to the second bearing assembly, an upper dust shield configured to limit contamination of the first bearing assembly, and a pulley secured to the shaft at the machined mounting surface using the pulley mounting bolts. Other embodiments are also described herein.

[0012] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [Brief explanation of the drawings] FIG. 1 is a typical illustration of a cross section of a low runout drive pulley through a spindle shaft using multiple sets of bearings with radial clearance to the spindle shaft. FIG. 2 is an exploded view of an exemplary embodiment of a low runout drive pulley. FIG. 3 is a typical embodiment of a low runout drive pulley mounted on a conventional internal combustion engine having a belt drive system. FIG. 4 is an exemplary embodiment of a detailed view of a low runout drive pulley system. FIG. 5 is another exemplary embodiment of a cross-sectional view of a low runout drive pulley through a spindle shaft using multiple sets of bearings with radial clearance to the spindle shaft of a belt drive system. DETAILED DESCRIPTION OF THE INVENTION

[0013] As mentioned above, described herein is a low runout drive pulley through a shaft that uses multiple sets of bearings with radial clearance to the spindle shaft.

[0014] In the following description, reference is made to the accompanying drawings, which form a part hereof, and which show by way of illustration at least one specific embodiment. The following description provides additional specific embodiments. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense. While the disclosure is not so limited, an understanding of various aspects of the disclosure will be gained through discussion of examples, including the drawings, set forth below. In some instances, a reference number may have an associated sub-label consisting of a lower case letter indicating multiple similar parts. When a reference number is mentioned without specifying a sub-label, it is intended that the reference number refer to all such similar parts.

[0015] FIG. 1 is an exemplary illustration of a cross-sectional view of a low-runout drive pulley through a spindle shaft using multiple sets of bearings with radial clearance relative to the spindle shaft. FIG. 1 shows a low-runout drive pulley system 100 according to the present disclosure. In some embodiments, the low-runout drive pulley system 100 includes, but is not limited to, a mounting bracket 105, a first bearing assembly 104, a second bearing assembly 144, a sleeve 106, a shaft bolt 107, a clamp flange 108, a shelf clearance 120, and a shaft 101. In some embodiments, it may also be beneficial to include a first shelf hard stop 122, a second shelf hard stop 124, an upper dust shield 109, and a bearing locking system 118. In some embodiments, the mounting bracket 105 may be cast from steel, an aluminum alloy, a magnesium alloy, or the like. In other embodiments, the mounting bracket may be manufactured by industrial origami, folding a sheet or plate, and joining corners by gluing, welding, tab joining, etc. The first shelf hard stop 122 and the second shelf hard stop 124 are molded or designed features into the mounting bracket 105. The first shelf hard stop 122 and the second shelf hard stop 124 may be machined into the mounting bracket 105 to ensure proper fit of the first and second bearing assemblies. In some embodiments, an interference fit may be used between the mounting bracket 105 and the first and second bearing assemblies 104, 144, while in other embodiments, a clearance fit may be used.

[0016] In some embodiments, the shaft 101 includes a precision-machined or ground mounting surface relative to the precision-machined or ground shaft diameter. In some embodiments, the shaft 101 may include features such as, but not limited to, threaded holes, through-holes, locking mechanisms, mounting arms, etc., to mount the belt pulley 102 via mounting bolts 103 or other mounting methods, or to accept shaft bolts 107. This may be beneficial to avoid requiring a press fit to mount a driven component, such as, but not limited to, a pulley, which could distort the mounting surface and increase runout. In some embodiments, the shaft may also incorporate a threaded hub 111 machined relative to the shaft diameter for mounting a protruding accessory such as a fan clutch, propeller, fan, pulley, etc. The amount of runout, and therefore wobble, of this accessory is controlled by the mounting surface 110 of this shaft relative to the rotating shaft after clamping the accessory with a prescribed torque. In some embodiments, it may be beneficial to machine the mounting surface relative to the shaft diameter 112. The shaft diameter 112 may be machined or ground to achieve low runout. These surfaces may also be turned or surface treated to reduce runout for the overall low runout drive pulley system 100.

[0017] In some embodiments, the protruding accessories may be supported by the first bearing assembly 104 and the second bearing assembly 144, at least one of which includes a two-raceway ball bearing or a two-raceway ball and needle bearing. The shaft 101 may be designed with clearance for the inner races of the bearings using a clearance fit. Either the first or second bearing assemblies may be press-fitted at their outer diameters into the mounting bracket 105 up to the first shelf hard stop 122. It may be beneficial to use a press fit on the outer races of both the first and second bearing assemblies relative to the mounting bracket. However, in some embodiments, it may be beneficial to seat the first and second bearing assemblies 104, 144 within the mounting bracket 105 with a clearance or transition fit to avoid distortion of the bearings due to an interference fit, i.e., a press fit. In this embodiment, the bearing securing system 118 may be designed to secure the bearings such that the outer races 113, 115 of the first and second bearing assemblies do not rotate in their positions, which may cause premature wear or deterioration of the rotating elements. In some embodiments, it may be beneficial to use a clearance or transition fit so that the low-runout drive pulley system 100 can be assembled and disassembled manually without the use of presses or special tools. In some embodiments, a sleeve 106 may be incorporated having clearance relative to the shaft 101 such that the first and second ends 166, 177 of the sleeve abut the first bearing inner race 114 and the second bearing inner race 116. In some embodiments, it may be beneficial to use a shelf clearance 120 between the first bearing outer race 113 and the second bearing outer race 115 in the fore-and-aft direction (along the sleeve first end 166 and sleeve second end 177) to achieve clamping via the sleeve 106 and not the rotating elements of the first and second bearing assemblies.A clamping flange 108, which also acts as a dust shield in some embodiments, is placed on the lower bearing inner race, with a clamping force acting via the shaft bolts 107 between the bearing inner races 114, 116 and the sleeve via the shaft bolts 107 and the clamping flange 108. In some embodiments, an upper dust shield 109 may be applied to further protect the first and second bearing assemblies from contamination that may be blown into the bearings in the environment by a large fan typically applied to the end of the shaft 101. In some embodiments, the bearing assembly closest to the pulley is restrained by a bearing restraint system 118. In some embodiments, the bearing restraint system may include, but is not limited to, a fixed first bearing assembly, at least one pin or clip design, a threaded retainer, a retaining ring (such as a circlip), or a bolted retainer plate to ensure limited (+ / - 0.01-0.005 mm) forward or rearward (along the shaft) movement of the bearing assembly due to thrust forces. In some embodiments, the first shelf hard stop 122 and the second shelf hard stop 124 may be present as a safety feature or an ease of assembly feature. Under sudden axial force, the first shelf hard stop 122 and the second shelf hard stop 124 prevent catastrophic damage.

[0018] 2 is an exploded view of an exemplary embodiment of a low runout drive pulley. In some embodiments, a low runout drive pulley system 200 may beneficially include a pulley 202, a pulley mounting bolt 203, a shaft 201, an upper dust shield 209, a first bearing assembly 204, a second bearing assembly 244, a mounting bracket 205, a sleeve 206, a clamp flange 208, a shaft bolt 207, etc. In some embodiments, low-runout drive pulley system 200 further includes a mounting bracket 205, a first bearing assembly 204 seated within mounting bracket 205, a second bearing assembly 244 seated within the mounting bracket, a sleeve 206 disposed between the first and second bearing assemblies, a shaft 201 radially clamped between first bearing assembly 204, sleeve 206, and second bearing assembly 244, and a clamping flange 208 having shaft bolts 207 configured and arranged to axially secure the shaft relative to the second bearing assembly, and may include pulley 202 secured to the shaft. In other embodiments, it may be beneficial to further include a shelf clearance (shown as 120 in FIG. 1 ) between a second shelf hard stop and the second bearing assembly. This may be beneficial to ensure that all clamping forces are transmitted through the inner bearing races (shown as 114, 116 in FIG. 1 ) and the sleeve of the first and second bearing assemblies. The first and second bearing assemblies may be any type of bearing that facilitates rotation of the shaft, including roller bearings, needle bearings, ball bearings, etc. In some embodiments, it may be beneficial to further include a bearing securement system (shown as 118 in FIG. 1 ) for the first bearing assembly 204. This includes securing the bearing by using a fixed first bearing assembly for the first bearing assembly 204. Other possible bearing securement systems include the use of retaining rings, C-clips, retaining pins, etc.

[0019] In some embodiments, it may be beneficial for sleeve 206 to contact the inner race of the first bearing assembly (shown as 114 in FIG. 1 ) at a first end of the sleeve (shown as 166 in FIG. 1 ) and the inner race of the second bearing assembly (shown as 116 in FIG. 1 ) at a second end of the sleeve (shown as 177 in FIG. 1 ). This means that the clamping force applied by shaft bolts 207 and clamp flange 208 is transmitted only by the inner race of the bearing and the sleeve, and not by the rotating elements, which may cause damage, wear, or premature failure of the rotating elements of the bearing. In some embodiments, it may be beneficial for shaft bolts 207 to clamp the inner race of the first bearing assembly, sleeve 206, and the inner race of the second bearing assembly together to apply an axial compressive force such that the inner race of the first bearing assembly, the sleeve, and the inner race of the second bearing assembly rotate simultaneously, i.e., roll together. In some embodiments, an axial compressive force from the shaft bolts engaging the internal threads of the shaft creates a clamping force that acts to engage the inner race of the first bearing assembly, the sleeve 206, the inner race of the second bearing assembly, the shaft 201 and the clamping flange 208 to rotate as a unitary assembly.

[0020] In some embodiments, it may be beneficial to position the first bearing assembly 204 on a first hard stop within the mounting bracket 205, with an end of the first hard stop contacting the outer race of the first bearing (shown as 113 in FIG. 1 ) to prevent the outer race from rotating within the mounting bracket. This may be beneficial in that the hard stop does not contact the rotating elements of the bearing and reduces rotation of the bearing within the mounting bracket 205. In some embodiments, it may be beneficial to press fit the outer races of the first and second bearing assemblies 204, 244 into the mounting bracket 205 to ensure the outer races do not rotate.

[0021] In some embodiments where large protruding masses, such as a fan clutch, fan, propeller, etc., are supported at the end of the shaft, it may be beneficial to include a threaded hub on the shaft to accommodate these protruding components. The threads on the threaded hub may be internal or external to accommodate the various protruding components. In some embodiments, it may be beneficial to include a radial clearance fit between the first and second bearing assemblies and the shaft to facilitate manual assembly and prevent damage due to press-fitting the bearing assemblies onto the shaft 201. This is beneficial to prevent distortion of the shaft 201 due to the press-fitting used to assemble the first and second bearing assemblies, thereby maintaining low shaft runout by using a radial clearance fit to manually assemble the first and second bearing assemblies 204, 244, sleeve 206, and shaft 201. In some embodiments, this radial clearance fit is a minimum radial clearance of 0.0025 mm, or a diametric clearance of 0.005 mm. In some embodiments, the shaft is radially clamped between the first bearing assembly 204, the sleeve 206, and the second bearing assembly 244. In some embodiments, this may be achieved by a radial clearance fit, but it may be necessary to provide sufficient clamping or retention force to reduce radial slop or movement within the assembly. This may be achieved by using a radial clearance fit to assemble the first and second bearing assemblies 204, 244, the sleeve 206, and the shaft 201. In some embodiments, this radial clearance fit is a minimum radial clearance of 0.0025 mm, or a diametric clearance of 0.005 mm. In some embodiments, this radial clearance fit provides sufficient frictional engagement to allow the first bearing assembly (inner race of the first bearing assembly), the sleeve, the second bearing assembly (inner race of the second bearing assembly), and the shaft 201 to rotate simultaneously or together within the mounting bracket 205.In some embodiments, this is further aided by the axial clamping force provided by the shaft bolts 207 and clamp flange 208. In some embodiments, it may also be beneficial for the first and second bearings to be serviceable and removable. It may be beneficial for the bearings to be removable by hand or with a gentle push without damaging the surrounding mounting bracket, and for replacement bearings to be replaced without reducing the strength of the mounting bracket 205. Making the first and second bearing assemblies 204, 244 removable may facilitate easier assembly and allow the low runout drive pulley system to be a serviceable component.

[0022] To further promote low axial runout, in some embodiments, the shaft 201 may include a shaft having a shaft diameter and a mounting surface, where the mounting surface is a machined surface relative to the machined shaft diameter. The shaft diameter and mounting surface may be machined, ground, or otherwise shaped to form a vertical or near-vertical surface. In some embodiments, the shaft may include internal threads to receive or engage a shaft bolt. In some embodiments, the shaft bolt 207 may be a threaded bolt or a locking pin using a locking mechanism, a push-pin type locking system, a ball-type locking pin, a spring-type locking pin, or the like. The shaft 201 may be designed to receive and engage these locking and locking systems to secure the shaft bolt 201 and the clamp flange.

[0023] To extend life and minimize maintenance, it may be beneficial to limit the amount of contaminants, such as dust, water, oil, and other particles, that enter the mounting bracket 205 and bearing housing. In some embodiments, it may be beneficial to include an upper dust shield 209 configured to limit contamination of the first bearing assembly. The upper dust shield 209 may be a polymer, metal, alloy, composite, or other shield that covers the first bearing assembly to protect it from contamination and is secured in place using a retaining ring, screws, or the like. It may also prevent or inhibit contamination from entering the support bracket's bearing housing, which may further extend the life of the low-runout drive pulley system 200. In other embodiments in which the mounting bracket 205 is not sealed, it may be beneficial to include a lower dust shield configured to limit contamination of the second bearing assembly. In some embodiments, the clamp flange 208 may function as the lower dust shield. The lower dust shield may be a polymer, metal, alloy, composite, or other shield that limits contamination and provides sufficient clamping force. In some embodiments, the pulley 202 may be molded as a single piece or may be multiple pieces secured and connected together via adhesives, screws, bolts, or the like. The pulley 202 may be molded from a material such as a polymer, metal, alloy, or composite. In some embodiments, the pulley 202 may need to be secured to the shaft. This may be achieved using pulley mounting bolts 203 or screws, by designing locking tabs, or by a press fit. In some embodiments, the pulley 202 may be overmolded onto the shaft. In some embodiments, it may be beneficial to overmold the pulley 202 onto the shaft 201 by injection molding a polymer or composite pulley onto a metal shaft. This can be achieved if the pulley 202 is molded from the polymer or composite material used for the pulley.In some embodiments, it may be feasible to overmold a pulley of a material such as an aluminum alloy onto a steel or other alloy shaft by a process such as die casting. Different embodiments may use pulleys of different materials. In other embodiments, it may be beneficial to press-fit the pulley 202 onto the shaft 201. This may be accomplished by heating the pulley 202 or cooling the shaft 201 and applying pressure to the parts using a fluid press, clamps, fixtures, etc.

[0024] In some embodiments, the low runout drive pulley system 200 includes a mounting bracket 205, a first bearing assembly 204 seated within the mounting bracket 205 on a first shelf hard stop, a second bearing assembly 244 seated within the mounting bracket 205, a sleeve 206 disposed between the first bearing assembly 204 and the second bearing assembly 244, and a sleeve 206 rotatably disposed between the first bearing assembly 204 and the second bearing assembly 244 and having radial clearance with respect to the first bearing assembly 204 and the second bearing assembly 244. The first bearing assembly 204 includes a shaft 201 having a machined shaft diameter, a machined mounting surface, and a threaded hub; a clamping flange 208 having a shaft bolt 207 configured and arranged to axially secure the shaft 201 relative to a second bearing assembly 244; an upper dust shield 209 configured to limit contamination of the first bearing assembly 204; and a pulley 202 secured to the shaft 201 at the machined mounting surface using pulley mounting bolts 203. Some embodiments may use two or more bearing assemblies to support the shaft. For longer shafts, three or more bearings may be required to support the shaft, however, in some embodiments, two bearings may be sufficient if the bearings are appropriately sized.

[0025] FIG. 3 illustrates an exemplary embodiment of a low-runout drive pulley mounted on a conventional internal combustion engine with a belt drive system 350. In some embodiments, it may be beneficial to include a belt drive system 350 to drive the low-runout drive pulley system 300. In some embodiments, this may be a conventional internal combustion engine in which the belt drive system 350 is driven by the crankshaft. In other embodiments, the belt drive system 350 may reside in a hybrid or electric motor, with the belt drive system 350 being driven by the electric motor. The belt drive system 350 may drive the pulley 302 of the low-runout drive pulley system 300 directly from the crank motor or electric motor, or it may be driven by a secondary belt system. The shaft 301 may be capable of supporting protruding components such as a fan clutch, cooling fan, or AC secondary pulley. The shaft 301 may have a threaded hub with internal or external threads to accept the protruding components. The mounting bracket 305 is configured to support the remaining components of the low runout drive pulley system 300 and to mount the system to an internal combustion engine, hybrid motor, or electric motor. The mounting bracket 305 may be manufactured using cast metal, composite, polymer, or other materials. Other manufacturing methods, such as industrial origami, may also be used.

[0026] FIG. 4 is an exemplary embodiment of a detailed view of a low-runout drive pulley system 400. In some embodiments, it may be beneficial to include a pulley 402 having a pulley mounting bolt 403 that mounts to a shaft 401. In some embodiments, to promote low runout, it may be beneficial for the shaft 401 to have a shaft diameter and mounting surface where the mounting surface is machined relative to the shaft diameter. The shaft diameter and mounting surface may be machined, ground, or otherwise prepared to provide a vertical, near-vertical, or other angularly related design. In other embodiments, various fastening methods can be used to secure the pulley 402 to the shaft 401. The pulley 402 and shaft 401 are designed to interlock with each other to provide a secure fit. In other embodiments, the pulley 402 may be press-fit onto the shaft 401 using an interference fit. A possible advantage of using machined surfaces and shaft diameters is that the invention is easy to assemble and disassemble, thereby leading to the possibility that the invention can be a useful part of recycling, new manufacturing, new logistics management, reducing resource waste and energy consumption. Utilizing the clearance between the shaft simplifies assembly and disassembly and prevents shaft distortion during press-fit. Machining the shaft diameter ensures that clearance fit tolerances are continually maintained while maintaining low axial runout of the assembly. The present invention can be used in applications with large drive shafts with protruding lumps. It eliminates the need for expensive tools to machine the faces after assembly is complete, which may help ensure there is no contamination from cutting oils or machine debris that can get into the bearing assembly.

[0027] FIG. 5 is another exemplary embodiment of a cross-sectional view of a low-runout drive pulley system 500 for spindle shaft applications using multiple sets of bearings with radial clearance on the shaft in a belt drive system 550. The invention comprises a shaft 501 including a mounting surface 510 that is precision machined or ground to a precision machined or ground shaft diameter (shown as 112 in FIG. 1). The shaft 501 may also feature a pulley 502 attached via a mounting bolt (shown as 103 in FIG. 1) to avoid incorporating a press fit that could distort the mounting surface at a microscopic level. However, in some embodiments, it may be beneficial to use a press-fit or interference-fit pulley, and in other embodiments, it may be beneficial to overmold the pulley 501 onto the shaft 501. The shaft 501 incorporates a threaded hub 511 that is precision machined to a shaft diameter 512 for mounting a protruding accessory, such as a fan clutch. The wobble of this accessory is controlled by the mounting surface of the shaft (shown as 110 in Figure 1) relative to the rotating axis after clamping the accessory to a predetermined torque. The load of the protruding portion may be supported by first and second bearing assemblies 504, 544, which have at least one ball bearing in the two raceways and one ball and needle bearing contained within the two raceways. The shaft 501 may be designed so that there is always clearance to the inner diameter of the bearing (inner race, shown as 114 and 116 in FIG. 1 ). In some embodiments, the first bearing assembly 504 may be press-fit into the bracket with its outer diameter up to the first shelf hard stop 522 of the mounting bracket 505. In some embodiments, there may be shelf clearance between the second bearing assembly 544 and the second shelf hard stop 524. In some embodiments, there may be an interference fit between the outer raceways of both bearing assemblies and the mounting bracket. A sleeve 506, designed to have clearance with the shaft, is assembled so that its ends abut the inner races of the first and second bearing assemblies. In some embodiments, it may be beneficial to have clearance applied to the outer races of the bearings in the fore-and-aft direction to ensure all clamping is through the sleeve 506. In other embodiments, a clamping flange 508, which also acts as a dust shield, may be placed on the inner race of the lower bearing, and a clamping force may be applied via shaft bolts 507, with this clamping force being applied between both bearing inner races and the sleeve and clamping flange 508 via shaft bolts 507. An upper dust shield 509 may be used to further protect the upper bearing from contamination that occurs in the types of environments commonly used with large fans. The first bearing assembly, which is typically the bearing assembly closest to the pulley, may be further restrained by a bearing fixation system (shown as 118 in FIG. 1 ) via a fixation or retaining clip to ensure it does not move forward due to thrust forces.

[0028] The above specification and examples provide a complete description of the structure and use of exemplary embodiments of the present invention. The above description provides specific embodiments. It should be understood that other embodiments may be contemplated and implemented without departing from the scope and spirit of the present disclosure. Accordingly, the above description should not be taken in a limiting sense. For example, elements or features of one example, embodiment, or implementation may be applied to other examples, embodiments, or implementations described herein to the extent not inconsistent with the content. The disclosure is not so limited, but an understanding of various aspects of the disclosure will be gained through the description of the examples provided.

[0029] Unless otherwise indicated, all numerical values ​​expressing characteristic dimensions, amounts, and physical properties should be understood to be modified by the term "about" whether or not the term "about" is immediately present. Accordingly, unless specifically indicated to the contrary, the numerical parameters referenced are approximations that may vary depending upon the desired properties believed to be obtainable by one of ordinary skill in the art using the teachings disclosed herein.

[0030] As used herein, the singular forms "a," "an," and "the" include plural references unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally used in its meaning including "and / or" unless the content clearly dictates otherwise.

[0031] Although the technology has been described in language specific to certain structures and materials, it is to be understood that the invention defined in the appended claims need not be limited to the particular structures and materials described. Rather, certain aspects are described as forms constituting the claimed invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the appended claims.

Claims

1. A mounting bracket and a first bearing assembly seated within the mounting bracket; a second bearing assembly seated within the mounting bracket; a sleeve disposed between the first bearing assembly and the second bearing assembly; a shaft radially fixed between the first bearing assembly, the sleeve, and the second bearing assembly; a clamp flange having a shaft bolt, the clamp flange constructed and arranged to axially secure the shaft relative to the second bearing assembly; A pulley is provided on the shaft. Pulley.

2. The pulley of claim 1 further comprising a shelf clearance between a second shelf hard stop and said second bearing assembly.

3. 2. The pulley of claim 1, wherein at least one of the first bearing assembly and the second bearing assembly is a needle bearing.

4. 2. The pulley of claim 1, wherein at least one of the first bearing assembly and the second bearing assembly is a ball bearing.

5. The pulley of claim 1 , further comprising a bearing securing system, said first bearing assembly being secured to said bearing securing system.

6. The pulley of claim 5 , wherein the bearing securing system comprises a fixed first bearing assembly.

7. The pulley of claim 5 , wherein the bearing securing system comprises a securing ring.

8. 2. The pulley of claim 1, wherein said sleeve contacts the inner race of said first bearing assembly at a first sleeve end and contacts the inner race of said second bearing assembly at a second sleeve end.

9. 2. The pulley of claim 1, wherein said first shelf hard stop contacts an outer race of said first bearing assembly.

10. The pulley of claim 1 , wherein the shaft comprises a threaded hub.

11. 2. The pulley of claim 1, wherein the shaft radially clamped between the first bearing assembly, the sleeve, and the second bearing assembly is radially clamped with a radial clearance fit between an inner race of the first bearing assembly, an inner surface of the sleeve, and an inner race of the second bearing assembly.

12. 2. The pulley of claim 1, wherein at least one of said first bearing assembly and said second bearing assembly is removable.

13. 2. The pulley of claim 1, wherein the shaft comprises a shaft having a shaft diameter and a mounting surface, the mounting surface being machined relative to the machined shaft diameter.

14. The pulley of claim 1 , further comprising an upper dust shield configured to limit contamination of the first bearing assembly.

15. The pulley of claim 1 , wherein the clamp flange includes a lower dust shield configured to limit contamination of the second bearing assembly.

16. 2. The pulley of claim 1, wherein the pulley is secured to the shaft by a pulley mounting bolt.

17. 10. The pulley of claim 1, wherein the pulley is overmolded onto the shaft.

18. 2. The pulley of claim 1, wherein the pulley is press fit onto the shaft.

19. 2. The pulley of claim 1, wherein the shaft bolt exerts an axial compressive force that acts to clamp the inner race of the first bearing assembly, the sleeve, and the inner race of the second bearing assembly together, causing the inner race of the first bearing assembly, the sleeve, and the inner race of the second bearing assembly to rotate simultaneously.

20. A mounting bracket and a first bearing assembly seated within the mounting bracket on a first shelf hard stop; a second bearing assembly seated within the mounting bracket; a sleeve disposed between the first bearing assembly and the second bearing assembly; a shaft rotatably disposed between the first bearing assembly and the second bearing assembly, the shaft having a radial clearance between the first bearing assembly and the second bearing assembly, the shaft having a machined shaft diameter, a machined mounting surface, and a threaded hub; a clamp flange having a shaft bolt, the clamp flange constructed and arranged to axially secure the shaft relative to the second bearing assembly; an upper dust shield configured to limit contamination of the first bearing assembly; a pulley secured to the shaft at a machined mounting surface using a pulley mounting bolt. Pulley.

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