Patent Application
20080075402
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Turning now to the drawings,
The sleeve 20 has a series of recesses 28 located on its outside diameter 22. The recesses 28 form part of a removal chamber contained by the tapered outside diameter 22 of the sleeve 20 interfacing the tapered inside diameter 16 of the bearing assembly 12. The removal chamber will be discussed in more detail below with reference to
The internal flange 14 has a stepped inside diameter 40, further having a recess 42 extending from the front face for a portion of the stepped diameter. A key or pin 44 extends from the uniform diameter 30 of the sleeve 20 and engages the recess 42. This prevents any relative motion between these parts that could otherwise generate frictional heat and lead to eventual failure or unscheduled maintenance of the system.
The system further includes an external flange or housing 46 having a front face 48 and back face 50. The external flange 46 is secured to the internal flange 14 via a plurality of fasteners 54. Countersunk holes 56 are located on the front face 48 of the external flange 46 allowing the fasteners 54 to pass through and engage the threaded holes 58 located on the front face 60 of the internal flange 14. A ring-like recess is located on the back face 50 of the external flange 46 forming an internal hydraulic chamber 62. An access port 64 is hydraulically coupled to the internal chamber 62 via a vertically cross-drilled hole 66. The access port 64 allows a user to externally couple a hydraulic pump (e.g., a hand pump, not shown) to the system. A piston 68 comprising a ring-shaped body is configured to interface the internal chamber 62 located in the external flange 46. The piston 68 has a seal 70 located on the outside diameter 72 and a further seal 74 located on the inside diameter 76, thereby sealing the internal hydraulic chamber 62 when the piston 68 is seated in the external flange 46.
In operation, applying a pressure to the hydraulic chamber loads the front face 78 of the piston 68, thereby urging the piston 68 to abut the front face 32 of the sleeve 20 and drive the sleeve into the bearing assembly 12. The pressure actuating mechanism will be discussed in more detail below with reference to
A screw 82 engages threaded holes 84 located in the external flange 46. The threaded holes 84 communicate with internal hydraulic chamber 62 allowing the screw 82 to load the front face 78 of the piston to secure it in place. A deformable sealing tape or other thread seal may be placed on the threads 86 of the screw 82 to maintain the internal pressure when the piston 68 is actuated. A plug 88 is threaded into the access port 66, sealing the hydraulic chamber 62 after the bearing assembly is installed on the shaft. Furthermore, the external flange 46 and the piston 68 are configured to remain in place after the bearing assembly is mounted to the shaft. The assembly, in accordance with the illustrated embodiment, then, constitutes a “leave-in-place” pressure actuated tool that greatly facilitates assembly and disassembly of the bearing, shaft and sleeve, without resort to complex additional tooling.
The tapered sleeve 20 is then pressed into engagement between the inner ring 98 and the shaft 92 via a pressure loaded piston 68. This is accomplished by hydraulically coupling an external pump 106 to the internal hydraulic chamber 62 via the access port 64 and a hydraulic fitting 108. As discussed above, deformable tape is used on the screws 82 to from a seal with the threaded holes 84 located in the external flange 46. The hydraulic seal is completed by an o-ring 110 located on the outside diameter of the piston 68 and an inner o-ring 112 sealing on the inner surface of the piston 68. It should be noted that any suitable sealing arrangement could be implemented without affecting the functionality of the system. The pump 106 is used to apply a pressure, as indicated by reference numeral 114, to the internal hydraulic chamber, thereby loading the piston 68. This advances the piston and brings the back face 80 of the piston 68 into contact with the front face 32 of the sleeve 20, resulting in axial movement of the sleeve, as indicated by reference numeral 116. This drives the tapered diameters together and results in an expansion/compression force, represented by reference numeral 118, between the parts. Thus, the pressure loaded piston is used to drive the sleeve to the initial or first position. As discussed above, determining the initial position is useful because it represents the point where all of the tolerances and initial clearance between mating parts has been removed. Once this initial position has been determined, the sleeve and/or bearing assembly is advanced a predetermined distance to properly reduce the internal clearance 100 of the bearing or otherwise fully engage the sleeve between the bearing and the shaft.
The initial position may be determined by monitoring the pressure inside the internal hydraulic chamber 62 via a pressure sensor 120 hydraulically coupled to the chamber. A pressure value that corresponds to the initial position can be pre-determined for the bearing assembly and shaft mounting configuration. This will typically be done empirically for particular sized of product. Once the desired pressure is obtained, the user then drives the sleeve and/or bearing assembly from the initial position to the final position. The distance between the initial position and final position corresponds to an axial sleeve and/or bearing assembly movement required to properly mount the bearing assembly to the shaft, and will also typically be specified for the particular product. Advancement through this pre-determined distance, as indicated by the letter “y” and reference numeral 122 in the figure, may be determined by placing a linear indicator 124 on the shaft to indicate the relative movement of the sleeve and/or bearing assembly from the initial position to the final position. Various types of indicators and indication techniques may be employed, and the invention is not intended to be limited to any particular linear indicator. The user then applies a pressure to the system until the desired axial sleeve and/or bearing assembly movement is observed.
Those skilled in the art will appreciate that this piston loaded drive system reduces frictional losses in the drive mechanism and allows the user to accurately determine and reliable quantify the initial position by monitoring the pressure in the hydraulic chamber, and the final position by measuring the sleeve and/or bearing assembly axial movement relative to the initial position. In other words, the invention eliminates the need to rely on a variable torque measurement to determine the initial or final position. Furthermore, the invention does not require the user to overcome an excessive amount of frictional resistance, thereby making the system easier to install.
Finally, as mentioned throughout the present discussion, the present mounting system is not limited to bearing assemblies and may be used to mount other mechanical elements to a shaft. For example, the system may serve to mount mechanical couplings used to couple one shaft to another. To complete this coupling a mechanical element (typically a coupling “half”) is directly mounted to the shaft. The present system may be used to mount this type of element, and many others, directly to a shaft offering all of the same benefits and advantages described above.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
