The present invention relates generally to a double row ball bearing having slug separators disposed between adjacent balls, and in particular to a double row ball bearing with balls separated by no more than fifteen degrees.
Many types of bearings can be used to support radial, thrust, or combination radial and thrust loads. Such bearings include ball, roller, plain, journal and tapered roller bearings. Typically, roller bearings include an outer ring having a generally cylindrical exterior surface and a generally cylindrical inner surface defining an interior area of the outer ring. An inner ring having a generally cylindrical outside surface is disposed in the interior area of the outer ring. A plurality of rolling elements, such as balls or needle rollers are disposed in a cavity between the outside surface of the inner ring and the inner surface of the outer ring. The outer ring and/or the inner ring can rotate relative to one another. For example, the inner ring may be secured to a shaft and the outer ring can rotate relative to the inner ring and the shaft.
In some instances, the rolling elements are disposed in pockets defined by a cage to space the rolling elements apart from one another. The cage can cause drag and increase the torque required to operate the bearing. In addition, the cage takes up space in the cavity between the inner ring and the outer ring. As a result, the size of the balls that can be used in a particular bearing can be limited by the presence of the cage. Thus smaller balls that can support less load than higher load capacity larger balls, are typically used in such bearings.
Bearings are typically used in hub-mounted vibration suppression systems (“HMVSS”). A HMVSS may be employed, for example, on the hub of a helicopter to suppress vibrations generated during operation. An example of such a system is disclosed in U.S. Patent Application Publication No. 20110027081, which is hereby incorporated by reference. The HMVSS comprises motorized imbalanced rotors that rotate at the blade-pass frequency to create centrifugal forces. By phasing the rotors, the magnitude and orientation of the centrifugal forces can be harnessed to inhibit hub vibrations. The HMVSS includes a bearing to facilitate rotation of the imbalanced rotors.
According to aspects illustrated herein there is provided a bearing for a hub-mounted vibration suppression system (HMVSS). The bearing includes an outer ring defining a first outer race and a second outer race; a first inner ring disposed in the outer ring opposite the first outer race; and a second inner ring disposed in the outer ring opposite the second outer race. A plurality of first rolling elements is disposed in a first cavity defined between the first inner race and the first outer race. The bearing includes a plurality of first slug separators. One of the first slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. A plurality of second rolling elements is disposed in a second cavity defined between the second inner race and the second outer race. The bearing includes a plurality of second slug separators. One of the second slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. Each of the plurality of first rolling elements have first centers that are spaced apart from one another by no more than 15 degrees and/or each of the plurality of second rolling elements have second centers that are spaced apart from one another by no more than 15 degrees.
According to other aspects illustrated herein there is provided a bearing for a hub-mounted vibration suppression system. The bearing includes an outer ring that defines a first outer race and a second outer race. The first outer race defines a first arcuate surface and the second outer race defines second arcuate surface. A first inner ring is disposed in the outer ring opposite the first outer race. The first inner ring defines a first inner race. The first inner race defines a third arcuate surface. A second inner ring is disposed in the outer ring opposite the second outer race. The second inner ring defines a second inner race. The second inner race defines a fourth arcuate surface. A plurality of first rolling elements is disposed in a first cavity defined between the first inner race and the first outer race. Each of the plurality of first rolling elements has a first radius of curvature and a first circumference. The bearing includes a plurality of first slug separators. One of the first slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. A plurality of second rolling elements is disposed in a second cavity defined between the second inner race and the second outer race. Each of the plurality of second rolling elements has a second radius of curvature and a second circumference. The bearing includes a plurality of second slug separators. One of the second slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. At least 30 percent of the first circumference of at least one of the plurality of first rolling elements engages the first arcuate surface and at least 30 percent of the first circumference of at least one of the plurality of first rolling elements engages the third arcuate surface; and/or at least 30 percent of the second circumference of at least one of the plurality of second rolling elements engages the second arcuate surface and at least 30 percent of the second circumference of at least one of the plurality of second rolling elements engages the fourth arcuate surface.
According to other aspects illustrated herein there is provided a bearing for a hub-mounted vibration suppression system. The bearing includes an outer ring defining a first outer race and a second outer race. The first outer race defines a first radius of curvature and the second outer race defines second radius of curvature. A first inner ring is disposed in the outer ring opposite the first outer race. The first inner ring defines a first inner race. The first inner race defines a third radius of curvature. A second inner ring is disposed in the outer ring opposite the second outer race. The second inner ring defines a second inner race. The second inner race defines a fourth radius of curvature. A plurality of first rolling elements is disposed in a first cavity defined between the first inner race and the first outer race. Each of the plurality of first rolling elements has a fifth radius of curvature and a first circumference. The bearing includes a plurality of first slug separators. One of the first slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. A plurality of second rolling elements is disposed in a second cavity defined between the second inner race and the second outer race. Each of the plurality of second rolling elements has a sixth radius of curvature and a second circumference. The bearing includes a plurality of second slug separators. One of the second slug separators is disposed between and separates each adjacent pair of the plurality of first rolling elements. The bearing has a first aspect ratio defined by the fifth radius of curvature divided by one of the first radius of curvature and the third radius of curvature and/or the bearing has a second aspect ratio defined by the sixth radius of curvature divided by one of the second radius of curvature and the fourth radius of curvature. The first aspect ratio is at least 0.6 and/or the second aspect ratio is at least 0.6.
In reference to
The first inner ring 120, the second inner ring 130, and the outer ring 140 are each generally annular and share a common central axis A. The first inner ring 120 has an annular configuration and defines a central aperture 122. An inner surface 124 of the first inner ring 120 generally defines a perimeter of the central aperture 122. The inner ring 120 has an I-beam cross section defined by a mounting web, for example a mount 126, extending between two flanges 120A and 120B. The mount 126 is configured to receive a balancing magnet assembly 193, for example one or more balancing magnets (as shown in
In the embodiment shown, the second inner ring 130 is configured in the same manner as the first inner ring 120, although, it should be understood that the present invention is not limited in this regard and different configurations are possible. The second inner ring 130 has an annular configuration and defines a central aperture 132. An inner surface 134 of the second inner ring 130 generally defines a perimeter of the central aperture 132. The inner ring 130 has an I-beam cross section defined by a mounting web, for example a mount 136, extending between two flanges 130A and 130B. The mount 136 is configured to receive at least a portion of the HMVSS 192 (as shown in
The outer ring 140 has an annular configuration and defines a central aperture 142 for receiving the first inner ring 120 and the second inner ring 130. The outer ring 140 has an inner surface 144. The inner surface 144 defines a first outer race 146 and a second outer race 148. The first inner ring 120 has an outer surface 128 that defines a first inner race 129. The first inner ring 120 is disposed in the outer ring 140 opposite the first outer race 146. The first inner ring 120 is disposed in the outer ring 140 opposite the second outer race 146. The second inner ring 130 is disposed in the outer ring 140 opposite the second outer race 148.
A first plurality of rolling elements 150, for example ball bearings is disposed between in a first cavity defined between the first inner race 129 and the first outer race 146. Each of the plurality of first rolling elements 150 has a first radius of curvature RB and a first circumference. A second plurality of rolling elements 160, for example ball bearings is disposed in a second cavity defined between the second inner race 139 and the second outer race 148. Each of the plurality of second rolling elements 160 has a second radius of curvature RB and a second circumference. Each of the plurality of first rolling elements 150 has a first radius of curvature RB and a first circumference. The first inner ring 120 is rotatable relative to the outer ring 140 about the central axis A. The first plurality of rolling elements 150 rollingly engages the first inner race 139 and the first outer race 146. The second inner ring 120 is rotatable relative to the outer ring 140 about the central axis A. The second plurality of rolling elements 160 rollingly engages the second inner race 139 and the second outer race 146. The first inner ring 120 is rotatable relative to the second inner ring 130 about central axis A. In one embodiment, the first plurality of rolling elements 150 and the second plurality of rolling elements 160 includes a plurality of generally spherical balls.
One slug separator 170 is disposed between and separates each adjacent pair of the first rolling elements 150. One second slug separator 180 is disposed between and separates each adjacent pair of the second rolling elements 160. The first plurality of slug separators 170 is disposed between the first inner race 129 and the first outer race 146. The second plurality of slug separators 180 is disposed between the second inner race 149 and the second outer race 148.
In reference to
In the embodiment shown in
The slug separators 170, 180 are sized to space adjacent pairs of the rolling elements 150, 160 apart from one another by a predetermined distance. As shown in
In the embodiment shown, the slug separators 170, 180 are made from flexible inert plastics. For example, the slug separators are cut from stocks of tubing or hosing. In one embodiment, the slug separators 170 are formed from a synthetic polymeric material such as bearing grade PEEK (poly ether ether ketone) and/or other material e.g., PTFE (polytetrafluoroethylene), polyimide, etc. It should be understood the slug configuration described above is provided for illustration purposes and is not intended to limit the scope of the disclosure as many different slug and ball configurations may be employed with the present invention. Use of plastic and tubular type slug separators 170, 180 facilitates weight reduction in the bearing 100.
By using individual slug separators 170, 180 inserted between adjacent rolling elements 150, 160, additional space is provided, as compared to a bearing using a ball separator cage to space the balls. As a result of the additional space provided through use of the slug separators 170, 180, it is possible to use rolling members having a greater diameter as opposed to a similar sized bearing in which a separator cage is employed. For example, as shown in
While first and second inner races 129, 139 and the first and second outer races 146, 148 are described has having the width W of 0.512 inch and rolling elements 150, 160 having the diameter of 0.3125 to 0.5 inch, the present invention is not limited in this regard as races and rolling elements of any size and configuration may be employed, including but not limited to races and rolling elements as described herein with reference to
Referring to
Thirty percent of the first circumference of at least one of the plurality of first rolling 150 elements engages the first arcuate surface 146C and thirty percent of the first circumference of at least one of the plurality of first rolling elements 150 engages the third arcuate surface 129C. In one embodiment, thirty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the second arcuate surface 148C and thirty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the fourth arcuate surface 139C. In one embodiment forty percent of the first circumference of at least one of the plurality of first rolling 150 elements engages the first arcuate surface 146C and forty percent of the first circumference of at least one of the plurality of first rolling elements 150 engages the third arcuate surface 129C. In one embodiment, forty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the second arcuate surface 148C and forty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the fourth arcuate surface 139C.
While thirty or forty percent of the first circumference of at least one of the plurality of first rolling 150 elements engages the first arcuate surface 146C and thirty or forty percent of the first circumference of at least one of the plurality of first rolling elements 150 engages the third arcuate surface 129C and thirty or forty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the second arcuate surface 148C and thirty or forty percent of the second circumference of at least one of the plurality of second rolling elements 160 engages the fourth arcuate surface 139C, the present invention is not limited in this regard as greater percentages (e.g., 45, 46, 47, 48, and 49 percent) of the circumference of the rolling elements 150, 160 can engage one or more of the first arcuate surface 146C, the second arcuate surface 148C, the third arcuate surface 129C and the fourth arcuate surface 148C.
Referring to
The bearing 100 has a first aspect ratio defined by the radius RB of one of the rolling elements 150 divided by either of the first radius of curvature ROUT of the first outer race 146 or and the third radius of curvature RN of the a first inner race 129. The bearing 100 has a second aspect ratio defined by radius RB of one of the rolling elements 160 divided by either of the one of the second radius of curvature ROUT of the second outer race 148 or the fourth radius of curvature RN of the second inner race 139. The first aspect ratio and/or the second aspect ratio is at least 0.6. In one embodiment, the first aspect ratio and/or the second aspect ratio is at least 0.7. In one embodiment, the first aspect ratio and/or the second aspect ratio is at least 0.8. In one embodiment, the first aspect ratio and/or the second aspect ratio is at least 0.9.
Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.
This application is a continuation in part of copending U.S. patent application Ser. No. 12/967,400, entitled “Ball Bearing and Pump for Cryogenic Use,” filed Dec. 14, 2010 which is a continuation in part of U.S. patent application Ser. No. 12/204,886, filed Sep. 5, 2008, which claims priority benefit of U.S. provisional application No. 60/967,540 filed Sep. 5, 2007, the contents of which are incorporated herein by reference in their entirety. This application is a continuation in part of copending U.S. patent application Ser. No. 13/475,097, entitled “Nutating Swash Plate Ball Bearing Assembly,” filed May 18, 2012, which claims priority benefit to U.S. Provisional Patent Application No. 61/487,843 filed on May 19, 2011 and U.S. Provisional Patent Application No. 61/521,823 filed on Aug. 10, 2011, the contents of which are incorporated herein by reference in their entirety. This application claims the benefit of U.S. Provisional Patent Application No. 61/639,261 filed on Apr. 27, 2012, the contents of which are incorporated herein by reference in its entirety.
Number | Date | Country | |
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60967540 | Sep 2007 | US | |
61487843 | May 2011 | US | |
61521823 | Aug 2011 | US | |
61639261 | Apr 2012 | US |
Number | Date | Country | |
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Parent | 12967400 | Dec 2010 | US |
Child | 13869293 | US | |
Parent | 12204886 | Sep 2008 | US |
Child | 12967400 | US | |
Parent | 13475097 | May 2012 | US |
Child | 12204886 | US |