This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2006-117032, filed Apr. 20, 2006; and No. 2006-226902, filed Aug. 23, 2006, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a rolling bearing of an oscillation roller and an oscillation method of a roller. More particularly, the present invention relates to a rolling bearing to be mounted in a oscillation roller that can be used as form rubber roller and dampening rubber roller used in a printing machine.
2. Description of the Related Art
Rollers are being widely used as rotary members in various fields of industry. In certain occasions, rollers that are used as rotary members are required to axially oscillate as they revolve. Rollers having such a functional feature are generally referred to as oscillation rollers.
While oscillation rollers are being widely used in various fields of industry, typical applications of oscillation rollers include form rubber rollers and dampening rollers of printing machines.
In the above-described printing machine, the form rubber rollers 3, 3 are held in contact with the printing plates 2, 2, . . . mounted around the plate cylinder 1 so as to be driven to rotate. Then, as a result, the ink supplied from the ink supply unit is made to transfer to the printing plates 2, 2, . . . around the plate cylinder.
A form rubber roller 3 that is being used in a printing machine is held in contact with the ink distributing roller 4 that transversally (axially) reciprocates and axially reciprocates along with the ink distributing roller 4. Such a roller is referred to as oscillation roller. By using an oscillation roller as a form roller, it is possible to cause the form roller to oscillate, following the ink distributing roller that transversally reciprocates. Then, as a result, the ink on the peripheral surface of the form roller is dispersed and transfer uniformly to the printing plates 2 mounted to the plate cylinder 1 to surround the latter.
Since the form rollers 3, 3 are liable to be damaged by the edges of the plate cylinder 1, the form rubber rollers 3, 3 are driven to transversally oscillate in order to avoid such damages. Additionally, the form rollers 3, 3 can give rise to frictional areas that are annular in the direction of revolutions at positions corresponding to the edges of the printing plates 2 and consequently deficiency of ink transferability and unevenness of ink density can arise at the corresponding positions in the subsequent printing process. It is necessary for the form rubber rollers to transversally oscillate in order to avoid such problems.
Ghosts may appear when printing an image where color densities can abruptly change in the transversal direction. As a general practice, the metal made rollers that are held in contact with the form rubber rollers are driven to axially reciprocate in order to avoid such ghosts.
Known oscillation rollers include the one disclosed in Jpn. Pat. Appln. Publication No. 60-101049. The disclosed oscillation roller has a roller shaft arranged at the inside of a roller coat member and held in position so as not to be able to revolve. The roller coat member of the form rubber roller that oscillates transversally is borne on the roller shaft so as to be able to revolve and axially movable. Additionally the axial stroke of the roller coat member is limited by two bushes 22, 24 at the opposite sides and pressure springs 26 are arranged at the respective lateral sides of the roller between the two bushes. However, known oscillation rollers are complex in terms of configuration and are accompanied by the problem of a high manufacturing cost. Thus, there is a strong demand for oscillation rollers that are structurally simple and can be provided at a low manufacturing cost.
In view of the above-identified circumstances, it is therefore an object of the present invention to provide a rolling bearing that has a simple structure and allows a roller to oscillate axially.
According to the present invention, the above object is achieved by providing a rolling bearing comprising a plurality of cylindrical rolls as rolling members between an inner ring and an outer ring thereof. The transversal distance of the surface of either or the surfaces of both of the inner ring and the outer ring vis-à-vis the raceway surfaces of the cylindrical rolls vis-à-vis is made longer than the axial length of the cylindrical rolls. With this arrangement, either or both of the inner ring and the outer ring of the rolling bearing can axially move.
The roller can oscillate axially once a rolling bearing according to the invention is fitted to either or both of a pair of shaft supporting sections of the roller. Another rolling bearing can be fitted to the other shaft supporting section of the roller located at the opposite side relative to the former shaft supporting section. When the inner ring or the outer ring of the former rolling bearing is moved axially and the roller is driven to move axially, the inner ring or the outer ring, whichever appropriate, of the latter rolling bearing follows the axial movement of the roller.
In another aspect of the present invention, there is provided an oscillation method of a roller according to which a rolling bearing is fitted to one of a pair of shaft supporting sections of a roller. Then, as a result, the inner ring or the outer ring of the rolling bearing becomes axially movable. Another similar rolling bearing is fitted to the other shaft supporting section of the roller located at the opposite side relative to the former shaft supporting section that that the roller may axially oscillate.
Thus, according to the present invention, it is possible to turn a conventional fixed roller that does not oscillate into an oscillation roller simply by remodeling the rolling bearings fitted to the respective shaft supporting sections. The remodeling of the rolling bearings consists in reforming the rolling bearings, in each of which a plurality of cylindrical rolls are arranged as rolling members between the inner ring and outer ring thereof. The reforming by turn consists in making either or both of the inner ring or the outer ring of each of the rolling bearings axially movable. Thus, the bearings can be reformed in a simple manner to turn the roller into an oscillation roller at low cost.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
FIGS. 17A1 through 17C1 are schematic illustrations of the relationship between the oscillation of an oscillation roller formed by using still another embodiment of rolling bearing of the present invention and the sliding motion of the inner ring of the rolling bearing;
In the rolling bearing 11, either the outer ring 12 or the inner ring 13 is made longer than the axial length of the cylindrical rolls 14. In
In the instance of
It will be clear from
It will be appreciated that, if the transversal length of the dent of inner ring and that of the outer ring are the same as the axial length of the cylindrical rolls in the strict sense of the word, there is no clearance between the inner and outer rings and the cylindrical rolls so that the rolling bearing cannot revolve at all. Therefore, the transversal length of the dent of the inner ring and that of the outer ring are made slightly greater than the axial length of the cylindrical rolls in ordinary rolling bearings in order to provide an appropriate clearance.
However, the transversal length of the dent of the inner ring 13 is made greater than the axial length of the cylindrical rolls 14 beyond the ordinary range of clearance according to the present invention. With this arrangement, the inner ring or the outer ring can move and hence the roller equipped with this bearing can move axially.
According to the present invention, the difference between the transversal distance of the dent of the inner or outer ring and the axial length of the cylindrical rolls 14 is between 2 mm and 20 mm, preferably between 3 mm and 5 mm. In terms of ratio, the axial length of the cylindrical rolls is preferably between 50% and 85% of the transversal distance of the dent of the inner or outer ring. While the inner ring 13 is integrally formed with one or two collars in
The transversal length of the surface of the inner ring 13 that faces the raceway surfaces of the cylindrical rolls 14 is greater than the axial length of the cylindrical rolls 14 in the description given above by referring to
The oscillation roller 20 of
The rolling bearing shown in
The rolling bearing shown in
The rolling bearing shown in
The rolling bearing shown in
The rolling bearing shown in
The rolling bearing shown in
As the swing roller 22 of
As the swing roller 22 swings transversally in the opposite direction (rightward), the oscillation roller 20 that is held in contact with the swing roller 22 and revolving swings in the direction opposite to the direction of the arrow (rightward) as shown in FIG. 17C1. Under this condition, the inner ring 13 of the rolling bearing moves in the direction opposite to the direction of the arrow (rightward) with respect to the cylindrical rolls 14 as shown in FIG. 17C1. Then, as a result, the oscillation roller 20 smoothly moves in the direction of the arrow, following the transversal swinging movement of the swing roller 22.
While the outer ring is fixed and the inner ring is moved in the above description, conversely the inner ring may be fixed and the outer ring may be moved. Then, the oscillation roller can be made to oscillate, following the transversal swinging motion of the swing roller.
A rolling bearing 21 as described above is fitted to each or either one of the shaft supporting sections of an oscillation roller 20. When a rolling bearing 21 is fitted to either one of the shaft supporting sections of an oscillation roller 20, a different rolling bearing having an outer ring or an inner ring that moves over a long range as shown in any of
An oscillation roller according to the present invention can suitably be used as the form roller of a printing machine. An oscillation roller according to the present invention can also find other applications and the scope of application of an oscillation roller is not particularly limited. An oscillation roller according to the present invention has a structure that is remarkably simple if compared with conventional oscillation rollers using a compression spring.
A pair of JIS B1513 NUP type rolling bearings having cylindrical rolls arranged in a single row, an outer ring that is provided with a pair of collars and an inner ring that is provided with a collar and a collar ring was brought in. The rolling bearings had the following dimensions—the outer diameter: 72 mm, the inner diameter: 30 mm and the width: 19 mm. Each of the rolling bearings was worked in such a way that the transversal distance of the surface of the inner ring facing cylindrical rolls became longer than the axial length of the cylindrical rolls by 4 mm. As a result, a pair of rolling bearings whose inner rings can move axially were prepared.
The rolling bearings were then respectively fitted to the supporting sections at the opposite sides of a form rubber roller 3 for transferring ink of a printing machine as shown in
The form roller is adapted to oscillate axially by way of a swing roller 22 (metal roller) as shown in
The oscillation roller had a core diameter of 110 mm×an outer diameter of 130 and a surface length of 1,620 mm. It was driven to revolve at a rate of 2,600 revolutions/min. The nip width was made to be equal to 7 mm. The rubber was nitrile rubber (NBR) with a hardness of 30.
The printing machine was operated for printing continuously for six months, 10 hours/day. No abrasion was observed on the surface of the form rubber roller at the position corresponding to the edges of the printing plate.
A pair of non-separable type JIS deep groove ball bearings having cylindrical rolls arranged in a single row was brought in as rolling bearings. The rolling bearings had the following dimensions—the outer diameter: 72 mm, the inner diameter: 30 mm and the width: 19 mm. The rolling bearings were then respectively fitted to the supporting sections at the opposite sides of a form rubber roller 3 for transferring ink of a printing machine as shown in
The printing machine was operated for printing continuously for a week (seven days), 10 hours/day and the surface of the form rubber roller was observed. Abrasion was clearly observed on the surface of the form rubber roller at the position corresponding to the edges of the printing plate.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2006-117032 | Apr 2006 | JP | national |
2006-226902 | Aug 2006 | JP | national |
Number | Date | Country | |
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Parent | 11788348 | Apr 2007 | US |
Child | 12802962 | US |