Solid material comminution or disintegration – Apparatus – Cooperating comminuting surfaces
Reexamination Certificate
1999-06-08
2001-06-26
Ostrager, Allen (Department: 3725)
Solid material comminution or disintegration
Apparatus
Cooperating comminuting surfaces
C241S295000
Reexamination Certificate
active
06250577
ABSTRACT:
BACKGROUND
The present application relates to bearing assemblies, and more particularly, rotor bearing assemblies capable of stressing a rotor element in an axial direction.
Shear shredder machines, briquetting machines, grinding machines and other types of material processing machines typically use a plurality of meshing, substantially parallel, counter-rotating roller assemblies. Typically, each of the roller assemblies includes a substantially cylindrical, material processing roller member mounted to a rotating shaft. For example, in a shear shredding apparatus, the roller member is a stack of cutter disks separated by spacer disks. Each of the roller assemblies is supported on a frame by a pair of supports mounted on ends of the frame. Each of the supports includes a bearing housing journaling a cylindrical bearing member mounted for simultaneous rotation with the shaft of the associated roller assembly.
Conventional bearing assemblies for use with such material processing devices commonly utilize roller-bearing components, such as tapered roller bearings, which bear axial as well as radial loads. A disadvantage with such roller bearing components is their expense and relatively short life span at high loading. Another disadvantage of such roller bearing components is that they provide a limited surface area for bearing the load of the rotational member. Another known disadvantage with conventional roller bearing components is that, as the roller bearing components wear, eventually necessary to replace the entire roller bearing assembly, which is expensive and time consuming. Accordingly, there is a need for a bearing assembly that has a greater life span than comparably sized roller bearing assemblies, that is less expensive than conventional roller bearing assemblies, that provides a greater surface area to bear the load of the counter-rotating members, and that is relatively easy and inexpensive to rebuild or re-furbish.
Additionally, conventional shear shredding and other material processing devices utilize stack tighteners on the ends of the rotating shafts. Such stack tighteners act to maintain the stack of cutting disks or other material processing roller members together in a compact relationship on the shear cartridge or roller assembly. With such an arrangement, a separate bearing member is positioned either axially within one of the stack tighteners or axially outside the stack tightener. Accordingly, the size of the shear shredding or material processing apparatus is partly dictated by such arrangement.
SUMMARY
The present invention is a journal bearing apparatus that is specifically configured to apply an axial load on a rotor element carried on the rotor shaft. One specific embodiment of the present invention is a combination journal bearing and stack tightener apparatus.
The apparatus of the present invention includes a bearing cylinder concentrically positioned on the rotor shaft between the rotor element and a first end of the rotor shaft, where the bearing cylinder includes a plurality of axially extending threaded bores distributed about the rotor shaft and extending completely through the bearing cylinder and includes an outer circumferential bearing surface; a pressure ring concentrically positioned on the rotor shaft between the bearing cylinder and the rotor element; a retainer for preventing the bearing cylinder from moving axially along the rotor shaft away from the rotor element; and a plurality of jack screws threaded into the threaded bores for forcing the pressure ring and bearing cylinder away from one another, thereby forcing the pressure ring axially against the rotor element. The bearing cylinder may be a plain bearing cylinder or may incorporate roller bearing elements distributed circumferentially thereabout.
In another embodiment, the apparatus of the present invention includes a bearing cylinder concentrically positioned on the rotor shaft between the rotor element and a first end of the rotor shaft, where the bearing cylinder includes a plurality of axially extending threaded bores distributed about the rotor shaft and extending completely through the bearing cylinder and also includes a plurality of recesses formed in the outer circumferential surface of the bearing cylinder; a pressure ring concentrically positioned on the rotor shaft between the bearing cylinder and the rotor element; a retainer for preventing the bearing cylinder from moving axially along the rotor shaft away from the rotor element; a plurality of jack screws threaded into the threaded bores for forcing the pressure ring and bearing cylinder away from one another, thereby forcing the pressure ring axially against the rotor element; and a plurality of bearing inserts made of a self-lubricating, abrasion-resistant polyamide material, where each of the inserts is positioned within a respective one of the plurality of recesses on the circumferential surface of the bearing cylinder to provide a bearing surface on the bearing cylinder.
Preferably, each of the bearing inserts includes a portion protruding radially from the corresponding one of the recesses. The inserts are formed from a reinforced carbon-fiber filled polyamide resin material and extend in a substantially axial direction along substantially the entire axial length of the bearing cylinder. The inserts are substantially oblong in shape. Also, it is preferred that the pressure ring is made from a hardened metallic material.
In an alternate configuration of the above embodiment, the bearing cylinder includes an annular depression or recess extending into the inner side surface of the bearing cylinder, where each of the plurality of axially extending threaded bores open into this annular depression, and the pressure ring includes an annular portion extending into the annular depression. Accordingly, by recessing an annular portion of the pressure ring partially into the annular depression, the pressure ring will act like a piston to substantially prevent the build up of contaminants between the jack screws and the pressure ring.
In another embodiment of the present invention, a bearing assembly that includes an outer cylindrical race having an inner cylindrical bearing surface; and a rotor shaft carrying a rotor element thereon; a bearing cylinder concentrically positioned on the rotor shaft between the rotor element and a first end of the rotor shaft and journaled by the cylindrical race, where the bearing cylinder includes a plurality of axially extending threaded bores distributed about the rotor shaft and extending completely therethrough and a plurality of recesses formed into the outer circumferential surface of the bearing cylinder; a pressure ring concentrically positioned on the rotor shaft between the bearing cylinder and the rotor element; a retainer for preventing the bearing cylinder from moving axially along the rotor shaft away from the rotor element; a plurality of jack screws threaded into the plurality of threaded bores and forcing the pressure ring and bearing cylinder away from one another, thereby forcing the pressure ring axially against the rotor element; and a plurality of bearing inserts made from a self-lubricating abrasion-resistant polyamide material, where each of the inserts are positioned within a corresponding one of the recesses so as to provide a bearing surface on the bearing cylinder facing the inner cylindrical bearing surface of the outer cylindrical race.
Preferably, each of the inserts include a portion protruding radially out from the corresponding one of the plurality of recesses, the inserts are formed from a reinforced carbon-fiber filled polyamide resign material, the inserts extend in a substantially axial direction approximately along the entire axial length of the bearing cylinder, and the inserts are substantially oblong in shape.
The cylindrical race is preferably mounted to a frame, where the frame has an opening for receiving at least the rotor shaft therethrough; and the bearing assembly preferably includes an annular seal extending radially inward from the
Hong William
Ostrager Allen
Standley & Gilcrest LLP
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