KR20050024280A - Ball bearing - Google Patents

Abstract

Ball bearing structures having a plurality of balls 30, 34 supported in cages 40, 50 and respective balls in rows 42, 44, 54, 58, 62 are offset relative to one another. In certain applications the rolling surfaces of the balls 30, 34 are retained relative to the rotating shaft 70 and the case surrounding the bearing. The number of balls 30, 34 and the number of rows 42, 44, 54, 58, 60 are predicted in certain applications. The invention is particularly effective in use for medical instruments. In other embodiments, the inner race and / or outer race may be used with balls and cages configured as such.

Description

Ball bearing

The present invention relates to a bearing for supporting a rotating member and more particularly to a ball bearing.

As is known in the art, there are a variety of ball bearings for supporting rotary shafts and the like, which are typically employed to transfer loads, support axial loads or thrust loads, and often maintain heavy radial loads. Has the property of Typically, a ball in a ball bearing configuration is supported between an inner race and an outer race, a pair of concentric rings and the balls lie in a plane perpendicular to the axis of rotation. Also in particularly high speed operation, the races are preloaded to keep the ball in radial alignment. Obviously, as is known to those skilled in the art, whether in single row or double row ball bearing configurations, misalignment of the balls relative to each other causes the misaligned balls to rotate faster than other balls, creating heat and friction. This may result in bearing failure or premature wear.

It has been found that improved ball bearings can be obtained by carefully orienting the balls in the bearings to make the circumferential paths of the balls somewhat helical. In this arrangement each ball follows an independent path, reducing the wear that has occurred in previously known ball bearings. The balls are supported in a cage and can be assembled with or without the inner race and / or outer race and do not need to be preloaded. When assembled without a race, the ball for a given envelope becomes larger, which is another feature that serves to improve the wear characteristics of the bearing.

In many medical instrument applications, ball bearings are typically used for radial loads because the support mechanism typically requires assembly and disassembly of the shaft supported by the bearing or the like. For example, in drills used in surgical operations, the cutters are driven by a motor, and the cutters are typically replaced with different sizes and types. Anspach Company, the assignee of the present patent application, manufactures and sells EMax, which uses cutters of different sizes and shapes that slide and mount into a drill.

Another example of a bearing used as a surgical tool is September 25, 2001. "Bearings for Surgical Instruments" disclosed and claimed in US Patent Application No. 09 / 962,989, which is assigned to the assignee of the present patent application and incorporated herein by reference. In one embodiment, the invention replaces one of the bearings in the Micro Dissection Attachment (MDA) disclosed in the patent application, so the patent application will be cited herein. As taught in previous patent applications, the MDA is thoughtfully configured to have two contact points of mating surfaces using a journal bearing made from a polymer of a polyimide resin and a graphite composition. Such a bearing configuration allows the surgeon to downsize the MDA at the distal end to enhance the cutter's line of vision, which facilitates the procedure in surgery. The journal bearing of the above teachings also improves the wear characteristics of the MDA. Like the journal bearings disclosed at the outset of US patent application Ser. No. 09 / 962,989, the ball bearings of the present invention provide a line of sight for surgeons who perform surgical procedures similar to those sought for MDA, while improving the load characteristics of surgical instruments. It can be made small enough to meet the characteristics having. Moreover, the ball bearing of the present invention provides a sufficiently reduced bearing, for example having a ball diameter of about 0.032 inch, while the upper limit of the ball size of the bearing is not limited. Thus, in surgical instruments where ball bearings only support radial loads, it is of fundamental importance that the size of the bearing is small, in fact the smaller the bearing, the better.

Bearings made in accordance with the present invention provide the following features although other features may be implemented.

1) When used without a race, the ball bearings have a large diameter and thus improve the wear characteristics of the bearings.

2) The balls do not roll in a common area so that each ball runs on an independent track, improving the wear characteristics of the bearings.

3) The bearing can be reduced in order to maintain the small diameter of the envelope.

4) The bearings are characterized by being easier to manufacture and cheaper than the bearings known so far, and are free of maintenance, reliable and have a long service life.

5) The material of the bearing may be any known material, whether ceramic or metal.

6) There is no need to load beforehand.

7) The assembly and disassembly of the bearing is simplified compared to the ball bearings known so far.

8) Ball misalignment is avoided.

The accompanying drawings illustrate and illustrate the invention more clearly and are not intended to limit the scope of the invention.

1 is a view of the end of a prior art ball bearing mounted to support a rotating shaft.

2 is a view of the end of a ball bearing of the present invention mounted to support a rotating shaft.

3 is a graph showing the inner and outer races of the present invention compared to the prior art with respect to the moving length of the ball.

4 is a schematic perspective view showing the movement pattern of the balls of the ball bearing of the present invention.

5 is a schematic view of the configuration of the ball bearing of the present invention in which two rolls of balls are used.

6 is a perspective view of a cage for two rolls of balls used in the present invention.

6A is a sectional view taken along line 6A-6A in FIG.

6B is a cross-sectional view taken along 6B-6B in FIG. 6A.

7 is a perspective view of two rows of cages illustrating an embodiment of one configuration of the present invention.

FIG. 8 is a view showing details of two rows of ball bearing configurations for the bearing configuration of the present invention. FIG.

It is an object of the present invention to provide an improved ball bearing.

A feature of the invention is that the balls are offset off-set such that each ball lies in a different plane transverse to the axis of rotation. There is no limit to the number or rows of balls that can be included in a single bearing and the balls in each row are predicted by a particular design.

Another feature of the invention in certain embodiments is that no race is used. In one embodiment the ball bearing may be configured with or without the inner race and / or the outer race.

The present invention is characterized by improving bearing life, adapting to high speed operation, miniaturizing to reduce the envelope size of the bearing chamber, low maintenance costs, and easy assembly and disassembly.

These and other features of the present invention will become more apparent from the following description and the accompanying drawings.

The present invention will be described as a preferred embodiment showing the details of the ball bearing of the present invention, and as understood by those skilled in the art, the ball bearing of the present invention has a wide range of applications and is not limited to any particular application. As will be appreciated by those skilled in the art, the present invention is particularly effective in the field of surgical instruments since the balls of the ball bearings of the present invention can be reduced.

1 and 2, a plurality of spheres circumferentially spaced therebetween to support the shaft 16 in a housing 18, such as an inner race 12 and an outer race 14 and a sleeve. A ball bearing configuration of a ball bearing of the prior art indicated by reference numeral 10 having a ball 15 and shaped into a housing 24 such as a shaft 22 and a sleeve and a plurality of circumferentially spaced spaces therebetween. A schematic comparison of the ball bearings of the present invention, indicated generally by reference numeral 20, with the provided balls. As can be appreciated from these figures, the ball bearing 10 of the prior art has an inner and outer race, whereas the ball bearing of the present invention does not have it. It is clear from this comparison that the ball bearing (FIG. 2) of the present invention is significantly larger than the ball (FIG. 1) of the prior art configuration. The configuration of the large balls provides a lower rate of spin and larger wear surfaces of the respective balls, so that the result of both parameters results in improved wear characteristics, thus extending the life of the bearing.

Furthermore, as can be seen in FIG. 3, when ball A, which represents one of the balls in the ball bearing of the present invention, is viewed against the outer race, it moves over a single track, while the six balls of the prior art The six balls B of the bearing move over a single track. Clearly, each of the balls of the ball bearing of the present invention is laterally displaced or offset relative to each other, and each of the six balls moves over a complementary independent track.

Observing the outer race as a comparison of the prior art ball bearings and the present invention, the six balls move over a single track compared to a single ball moving over a single track. Although the track of prior art ball bearings is long, the number of balls moving over the same distance in the prior art configuration is much greater than the travel distance in the present invention.

Thus, in accordance with the present invention, each of the balls 26 is offset relative to each other. This is shown in FIG. 4, where balls A are shown as offset and each ball is laterally relative to each other such that each ball lies parallel to the plane passing through the axis of rotation or axial center of the bearing. Is displaced. Thus, as indicated by lines C, D, E, F, G, and H, each ball rolls over its own track. As the ball bearing of the present invention is less worn on a single given track when compared to the ball bearing of the prior art, the life of the bearing made according to the invention is improved.

The ball bearing 20 may be made of metal or nonmetallic material. Obviously, if a nonmetallic material is used, the unit is not affected by things like magnets or electromagnets.

5 is a schematic diagram of another embodiment of the present invention. In certain embodiments using prior art ball bearings, it is desirable to use a pair of side mounted ball bearings. Obviously, in this arrangement the axial alignment of the balls in each ball bearing may coincide with the axial alignment or may be displaced from the axial alignment, the occurrence of which is incidental, ie in one of the ball bearings. The relationship of the balls of the ball has nothing to do with the balls of the ball in other ball bearings, and the balls can only find their position. On the other hand and in accordance with the invention, the balls held by a single cage, which will be described in more detail below, can be axially offset or displaced. This is best shown in FIG. 5A, which is a schematic drawing of the present invention in which a single row of balls in the ball bearing of the present invention is held by a cage schematically shown as circle 32. When the second row of balls as shown in FIG. 5B have been added, the two balls 30 are circumferentially displaced in a single offset row of balls and the single ball 30 can be seen in the axial view. It may be substantially oriented between the two balls 30, or in another way in which the balls of the first row are radially offset from the balls of the second row. If a straight line is axially drawn through the center of the ball in the balls of the first row, such a line will not coincide with the balls of the second row. In this example the cage 36 will no longer accept the balls in the second row. It is from the above that the balls 30, 34 have an upper surface 47 to be held against the inner wall of the bore supporting the bearing and a lower surface 49 below the cage 36. Will be understood. This arrangement not only improves the distribution of radial loads compared to two rows of balls by mounting two ball bearings side by side, but also coincides by a single bearing acting over the elongated length of the envelope of the bearing cavity. Since the two rows of balls interact with each other, the structural integrity of the ball bearings is improved.

6 and 7 show the cage of the ball bearing of the present invention, wherein the cage 40 shown in FIG. 6 is for two rows of ball configurations and the cage 50 shown in FIG. 7 has three cages. It is about the ball configuration of the column. As can be seen in FIG. 6, the two rows of ball cages 40 are cylindrical hollow main body portions, or a member 41, such as a sleeve, is shaped like an outer cylinder. It has a surface 43 and an inner cylindrical surface 45 and has two rows 42, 44 of circumferentially spaced conical shapes located thoughtfully in the path of the helical. . Each of the plurality of holes 46, 48 serves to hold a single spherical ball 26 (FIG. 1) so that a portion of the ball protrudes past the lower portion of the conical hole and the upper portion of the ball 26 It protrudes through the uppermost part of the conical hole, that is, the diameter of the upper part of the hole is larger than the diameter of the ball bearing 26 and the diameter of the lower part of the widened hole is smaller than the diameter of the ball bearing 26. The cage 50 supporting the three rows of balls as shown in FIG. 7 is similarly configured, ie holes 52 in row 54, holes 56 in row 58, and row 62. The holes 60 of are all conical shaped and of the same dimensions having a larger diameter close to the outer surface and each row of holes is oriented to follow a helical path to offset the ball when assembled.

From the above, ball bearings made in accordance with the present invention require a smaller envelope size for the bearing cavity when one or the other race is not used, and in this type of configuration a mating contact with the ball. The ball is larger compared to the same outer diameter bearing of the prior art structure in order to have the components have a wider contact surface. In the present invention, since the balls are offset, each ball travels on its own track, thus improving wear on the bearings. Moreover, especially in two, three or multiple rows of balls, the load bearing performance of the bearings is increased so that smaller bearings can be used compared to the ball bearings known so far.

As mentioned in the above paragraph, ball bearings made in accordance with the present invention are extremely effective for medical instruments because the balls can be made extremely small, i.e., 0.032 inch ± 0.05 inch. In addition, as mentioned in the above paragraph, the ball bearing of the present invention is easy to assemble. In the prior art ball bearings having an inner race and an outer race, the dimensions are important so that the unit is pressed onto the surface of the mating chamber and the shaft and balls must be perfectly aligned with respect to each other and with respect to the shaft. In the present invention, there is no interference fit or the like and the balls are rolled into a tube or sleeve that defines a bearing chamber on the shaft to facilitate assembly and disassembly. This is best shown in FIG. 8, which merely illustrates an exemplary method in which bearings can be mounted and used. For example, the rotary shaft 70 may be a shaft of a cutter supported in the tube 72 by a ball bearing 74 made in accordance with the present invention. This figure has three rows (X, Y, Z) and each row holds six spherical balls 80 held in conical holes 82 formed in cage 84. The rolling surfaces of the ball 80, ie the upper surface 83 and the lower surface 85, extend out of or beyond the outer surface 91 and the inner surface 93 of the main body 89 of the cage 84. Extend inwardly) to maintain directly against the outer surface 90 of the shaft 70 and against the inner surface 92 of the tube 72, respectively; It should be understood that there is no inner race or outer race. In this example, the diameter of the shaft 70 is substantially 0.093 inches, the outer and inner diameters of the sleeve 72 are substantially 0.237 inches and 0.187 inches, respectively, and the balls are substantially 0.031 inches. These dimensions are obviously very small, so the bearing 74 is reduced. Assembling these units as each component is disassembled involves sliding the cage onto the shaft 70 (if the shaft in use is not suitable, the cylindrical fixture serves the same purpose, and once the bearing is Will be removed.) Applying a small amount of commercially available hard grease to allow a small amount of grease to migrate into each of the holes 82; Mounting) (the balls are so small that they may require the use of forceps to manipulate the balls), and sliding the cage into the tube 72 (by grease, the balls will be held in their respective holes). This is simple because the ball rolls on an individual surface. The ball bearing 74 is then fixed in place by providing a shoulder 94 at one end and a nose piece 96 at the other end to be held relative to the individual ends of the cage. The nose portion is press fit into the end of the tube 70 such that the bearing cannot be removed. Although the details of the present invention have been described in connection with ball bearing assemblies that do not have an inner race and an outer race, those skilled in the art will understand that the principles of the present invention can be applied to ball bearing configurations having both an inner race and an outer race. will be. Clearly, in applications where it is necessary to maintain a reduced or small outer diameter or where such is desired, the ball bearing of the present invention will be constructed without inner race and outer race.

Although the present invention has been shown and described with respect to its detailed embodiments, those skilled in the art will understand that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention.

The ball bearings of the present invention can be applied to small instruments such as surgical instruments.

Claims (20)

Cage 40 having a plurality of holes 46 and 48 arranged to be offset from each other, and a plurality of spherical balls 30 and 34 respectively mounted in the plurality of holes 46 and 48 respectively. A ball bearing structure comprising: each of the spherical balls of the plurality of spherical balls has an upper cloud surface 47 and a lower cloud surface 49, wherein the spherical balls of the plurality of spherical balls The upper cloud surface 47 of each of the balls 46, 48 extends above the upper surface of the cage 40, and the lower cloud surface 49 of each of the spherical balls is of the cage 40. Ball bearing structure, characterized in that extends below the lower surface of the. The method of claim 1, And the plurality of holes (46,48) are spaced circumferentially and oriented to define a helical pattern. The method of claim 2, Each of the holes 46-48 is conical and extends through the cage 40 so that the wide opening of the conical holes 46, 48 is greater than the diameter of each of the spherical balls 30, 36. And a small opening of the conical hole (46, 48) is smaller than the diameter of each of the spherical balls (30-36). The method of claim 3, wherein The wide diameter of the conical holes 46 and 48 is on the outer surface of the cage 40 and the small diameter of the conical holes 46 and 48 is on the inner surface of the cage 40. Ball bearing structure. A ball bearing structure having a cage 40 having a main body, such as a sleeve, wherein the main body 41 has an upper cylindrically shaped surface 43 and an upper cylindrically shaped surface 43. A plurality of circumferentially spaced holes 46, 48 are formed in the main body 41 and extend therethrough, the inner cylindrically shaped surface 45 concentric with Each of the columnar spaced holes 46, 48 are oriented to offset from each other to substantially define a helical path, and each of the plurality of spherical balls 30, 34 is in each of the holes 46, 48. Mounted and thereby retained, each of the plurality of spherical balls 30, 34 has an upper cloud surface 47 and a lower cloud surface 49, whereby the upper cloud surface 47 defines the main body ( 41. Top cylindrically shaped surface 4 Ball bearing structure, which extends beyond 3) and wherein the lower rolling surface (49) extends beyond the inner cylindrically shaped surface (45). The method of claim 5, wherein Each of the circumferentially spaced holes 46, 48 is conical shaped, the upper cylindrically shaped surface 43 is of wide diameter and the lower cylindrically shaped surface 45 is of small diameter. Ball bearing structure, characterized in that. The method of claim 5, wherein The plurality of circumferentially spaced holes 46, 48 are formed in the first row 42 and the main body 41, axially spaced apart from the first row 42, offset from each other, and substantially helical. Define a second row 44 of a plurality of circumferentially spaced holes 46, 48 that are oriented to define a path, and each of the plurality of additional spherical balls 30, 34 is said second row 44. Mounted in and maintained by each of the circumferentially spaced holes of ss, each of the plurality of additional spherical balls 30, 34 having an upper cloud surface 47 and a lower cloud surface 49. Whereby the upper cloud surface 47 extends beyond the upper cylindrical surface 43 of the main body 41 and the lower cloud surface 49 extends beyond the inner cylindrical surface 45. And the second row 42 of holes 42 is the first row and number of holes 44 and Ball bearing structure characterized by the same in dimensions. The method of claim 7, wherein The plurality of circumferentially spaced holes 46 in the first row 42 are radially from the plurality of circumferentially spaced holes 48 in the second row 44 of circumferentially spaced holes. Ball bearing structure, characterized in that offset to. The method of claim 7, wherein A plurality of circumferentially spaced portions formed in the main body 41 and axially spaced apart from the first row 54 and the second row 56 and offset from one another and oriented to substantially define a helical path. A third row 62 of holes 60, each of a plurality of other additional spherical balls 30, 34 being spaced apart in the circumference of each of the third rows 62. Mounted in and held by, each of the plurality of additional additional spherical balls 30, 34 has an upper cloud surface 47 and a lower cloud surface 49 whereby the upper cloud surface 47 is Extends beyond the upper cylindrical surface 43 of the main body 41 and the lower rolling surface 49 extends beyond the inner cylindrical surface 45 and the second row of holes 58 The same in number and dimensions as the first row of holes 58 Ball bearing structure. The method of claim 9, The plurality of circumferentially spaced holes 56 in the second row 58 are arranged in a plurality of circumferentially spaced holes 60 in the third row 62 of the circumferentially spaced hole 60. Ball bearing structure, characterized in that spaced radially away from the. A rotary shaft 70, a tube 72 surrounding the rotary shaft 70 and radially spaced therefrom, and a ball bearing 74 mounted in the space, wherein the ball bearing 74 is separated from each other. A ball 80 having a cage 84 having a plurality of holes 82 arranged to be offset and each of the plurality of spherical balls 80 is mounted in each of the plurality of holes 82, the plurality of spherical shapes Each of the spherical balls 80 of phosphorous balls has an upper cloud surface 83 and a lower cloud surface 85 and each of the spherical balls 80 of the plurality of spherical balls The upper cloud surface 83 extends above the upper surface of the cage 84 and the lower cloud surface 85 of each of the spherical balls 80 extends beyond the lower surface of the cage 84. And the upper cloud surface 83 is the inner surface 92 of the tube 72. And the lower cloud surface (85) is in contact with the outer surface (90) of the shaft (70). The method of claim 11, And the plurality of holes (82) are circumferentially spaced and oriented to define a substantial helical pattern. The method of claim 12, Each of the holes 82 is conical shaped and extends through the cage 74 and the wide opening of the conical shaped hole is larger than the diameter of each of the spherical balls 80 and the conical shaped hole. And the small opening is smaller than the diameter of each of the spherical balls (80). The method of claim 13, And a large diameter of the conical hole (82) on the outer surface of the cage and a small diameter of the conical hole (82) on the inner surface of the cage (74). A ball bearing for supporting the rotary shaft 70 with respect to the tube member 72, wherein the ball bearing 74 is mounted in an annular space between the rotary shaft 70 and the tubular member 72, and The ball bearing 74 has a cage 84 having a main body 89 such as a sleeve, the main body 89 having an upper cylindrical surface 91 and an upper cylindrical surface ( A plurality of rows (X, Y, Z) of a plurality of circumferentially spaced holes (82) having an inner cylindrical surface (93) concentric to 91 are formed in and through the main body (89). Each of the plurality of circumferentially spaced holes 82 extending in each of the plurality of rows X, Y, Z are oriented to be offset from each other and substantially define a helical path. Each of the spherical balls 80 is mounted in the respective hole 82. And thereby retained, each of the plurality of spherical balls 80 has an upper cloud surface 83 and a lower cloud surface 85 such that the upper cloud surface 83 is an upper portion of the main body 89. Extends beyond the cylindrical surface 91 and the lower rolling surface 85 extends beyond the inner cylindrical surface 93 of the main body 89 and the upper rolling surface 83 is the tubular member. Ball bearing, characterized in that it is held against (72) and the inner rolling surface (85) is held against the shaft (70). The method of claim 15, Each of the circumferentially spaced holes 82 in each of the plurality of rows X, Y, Z is conical shaped to have a wide diameter on the upper cylindrical surface 91 and to Ball bearing, characterized in that it has a small diameter on the surface (93), which is cylindrical in shape. The method of claim 16, Each of the plurality of circumferentially spaced holes 80 in at least one X of the rows X, Y, Z is formed in a main body 89 and axially spaced from the first row. Each of the plurality of additional spherical balls 80, which are radially offset with a plurality of circumferentially spaced holes from different rows Y, and are offset from one another and substantially define a helical path. Mounted in and maintained by each of the circumferentially spaced holes 82 of the plurality of rows X, Y, Z, each of the plurality of additional spherical balls 80 is defined by an upper cloud surface ( 83) and a lower cloud surface 85 whereby the upper cloud surface 83 extends beyond the upper cylindrical surface 91 of the main body 89 and the lower cloud surface 85 Past the inner surface 91 of the cylinder Chapter is the second row (Y) is a ball bearing, characterized in that like in the first column (Y) and the number and dimensions of the hole 82 of the hole 82. The method of claim 17, The plurality of circumferentially spaced holes 82 in the row Z are radially from the plurality of circumferentially spaced holes 82 in the other rows X of the circumferentially spaced holes 82. Ball bearing characterized in that the offset. As a method of installing a ball bearing 74 supporting a rotary shaft 70 in a tubular member 72 into a bearing cavity, I) providing a cage 84 having a plurality of conical shaped holes 82 mounted circumferentially around the periphery; ii) mounting the cage 84 on the rotary shaft 70; iii) coating the holes 82 of the cage 84 with grease; iv) inserting a spherical ball 80 into each of the holes 82; v) the spherical ball 80 such that the upper rolling surface 83 of the spherical ball 80 is held relative to the tubular member 72 and the lower rolling surface 85 of the spherical ball 80 is held against the shaft 70. And inserting the cage (84) into the bearing cavity. The method of claim 19, A fixture of the same diameter as the rotary shaft 70 replaces the rotary shaft; And, I) removing the fixture and inserting the rotary shaft (70) into the ball bearing (74).