This invention relates generally to ring bearings and specifically relates to a slewing ring with enhanced dimensional stability.
Bearings are widely used to minimize friction between rotatably coupled components that exhibit movement relative to one another. Components used in the fields of medicine, automotive manufacturing, power generation, and the like, can require two components to rotate relative to one another and maintain tight tolerances with respect to their location about a axis. A slewing ring affords for one component to rotate about a axis relative to a second component. However, some applications expose the components and the slewing ring to shearing or off-axis loading which can subsequently cause excess movement in undesirable off-axis directions and/or increase the friction between said components. Therefore, it is desirable to improve the performance of slewing rings, particularly when said rings are under high stress or loading conditions. The stewing ring of the present invention affords for enhanced dimensional stability of the ring and components attached thereto. These and other advantages of the invention will be apparent from the drawings and discussion presented herein.
A slewing ring affording enhanced dimensional stability is provided. The ring includes an annular outer race and an annular inner race rotatably coupled to the outer race. The outer race and the inner race are arranged concentrically about an axis. At least one ball bearing is located between the outer race and the inner race. In addition, the inner race includes an annular upper member and an annular lower member. The upper member of the inner race has a retaining segment that extends coaxially with the axis. The lower member of the inner race has a U-shaped recess that is adapted to accept the retaining segment. The retaining segment in combination with the U-shaped recess affords for a slewing ring with increased capability to handle applied shearing or off-axis loading, and thereby provides enhanced dimensional stability.
Referring to
Turning to
The inner wall 20 is defined by first 28, second 30 and third 32 surfaces, and a step 34. The third surface 32 is disposed adjacent the bottom end 26 of the cross section. The third surface 32 has a diameter that is smaller than the first 28 and second 30 surfaces wherein said diameter is measured from the axis 5. In the alternative, the third surface 32 has a diameter that is larger than the first 28 and second 30 surfaces. The first surface 28 is disposed adjacent the top end 24. The first 28 and second 30 surfaces have generally the same diameter. In the alternative, the first 28 and second 30 surfaces do not have the same diameter.
The step 34 is positioned between the first 28 and second 30 surfaces and protrudes radially inwardly towards axis 5 relative to said surfaces 28 and 30. The step 34 has a diameter that is smaller than that of the third 32 surface, or in the alternative step 34 has a diameter that is large than that of the third surface 32.
Radii 40 are defined between the step 34 and the first 28 and second 30 surfaces, and thereby afford a first bearing ring seat surface 29 having the radius 40 and a second bearing ring seat surface 31 having the radius 40.
The inner race 12 has annular upper 42 and lower 44 members. The upper member 42 is fixedly secured to the lower member 44 using any attachment means known to those skilled in the art, illustratively including a plurality of bolts, rods or pins (not shown) with corresponding apertures. In one embodiment bolts extend through corresponding bores 45 and 57 formed in the upper 42 and lower 44 members, respectively, as shown in
Although not required for the present invention to be operative, one embodiment includes the upper member 42 of the lower race 12 with a generally rectangular cross section, the length of which is arranged orthogonally with respect to the length of the outer race 14. The upper member 42 has opposite upper 46 and lower 48 walls, and opposite inner 50 and outer 52 ends. The outer end 52 has a diameter that is larger than the diameter of the outer wall 22 of the inner race 12.
The plurality of apertures or bores 16 of the inner race 12 can be formed in the upper member 42 and arranged along a region defined between the outer end 52 of the upper member 42 and the outer wall 22 of the outer race 14. Bolts, pins or rods can be placed at least partially within the bores 16 in order to afford attachment of a component to the upper member 42.
A flange 60 extends in an axial direction from the lower wall 48 of the upper member 42, as shown in
A first 64 and second 66 retaining segments extend coaxially, with respect to the axis 5, from the middle surface 62. The first 64 and second 66 retaining segments are generally parallel with each other, such that a generally U-shaped upper pocket 65 is formed therebetween, as shown in
The distal end of the second retaining segment 66 has an angled surface 70 facing radially inwardly toward the first retaining segment 64 at a 45 degree, or otherwise acute, angle with respect to the middle surface 62 of the flange 60. The second retaining segment 66 has an outside surface 65 opposite and generally parallel to the inside surface 68 of the first retaining segment 64. The outside surface 65 has a smaller diameter than that of the first surface 28 of the outer race 14 and is adjacent thereto.
The lower member 44 of the inner race 12 can optionally have a generally L-shaped cross-section. The lower member 44 includes an outside surface 72 having helical threads for threadingly engaging the threads on the inside surface 68 of the upper member 42. A step 74 extends radially outwardly relative to the outside surface 72 of the lower member 44. The step 74 is positioned below the outside surface 72 of the lower member 44.
A third retaining segment 76 extends axially from the step 74 and toward the flange 60 of the upper member 42. The distal end of the third retaining segment 76 has an angled surface 82 spaced apart and opposing the radial surface 70 of the second retaining segment 66. The third retaining segment 76 is generally parallel to and spaced outwardly relative to the outside surface 72 of the lower member 44.
The third retaining segment 76 and the outside surface 72 define a U-shaped recess 80 therebetween, said recess 80 adapted to accept the first retaining segment 64 of the upper member 42, as shown in
Preferably the depth of the U-shaped recess 80 and the portion of the third retaining segment 76 accepted therein is between 0.05 and 35% of the overall axial height of the inner race 12. More preferably the depth of the recess 80 is between 1 and 25% of the overall axial height of the inner race 12, and even more preferably is between 1 and 15%. Even yet more preferably, the depth of the U-shaped recess is between 2 and 10% of the overall axial height of the inner race 12.
The step 74 of the lower member 44 includes an angled surface 86 opposite the angled surface 82 on the third retaining segment 76. The angled surface 86 is oriented at a 45 degree, or otherwise acute, angle relative to the axis 5 of the ring bearing 10.
A leg 90 extends radially outward relative to, and is positioned below, the step 74. A fourth retaining segment 92 extends axially from the leg 90 in a direction towards the flange 60. The distal end of the fourth retaining segment 92 has an angled surface 94 spaced apart and generally parallel with the angled surface 86 of the step 74. The fourth retaining segment 92 is generally parallel to and spaced apart from the step 74 and defines a lower pocket 95 therebetween. The lower pocket 95 is generally symmetrically opposite to the upper pocket 65 of the upper member 42.
The upper pocket 65 and lower pocket 95 each include a corner 67 and 97, respectively, as shown in
A first bearing ring 101 and a second bearing ring 102, each having a radius 40, are seated on opposite sides of the step 34 of the outer race 14. A third bearing ring 103 and a fourth bearing ring 104, also having a radius 40, are seated adjacent to corners 67 and 97. Specifically, the rings 101, 102, 103 and 104 are seated against first seat surface 29, second seat surface 31, third seat surface 61 and fourth seat surface 91, respectively.
Each of the rings 101 through 104 include bearing surfaces 105, said surfaces 105 being arcuate and having the same curvature as a ball bearing to be placed in contact therewith. In the alternative, the bearing surfaces 105 are non-acruate surfaces adapted to accept a bearing that is located adjacent to and in contact therewith. In the present embodiment, spaces are defined between the bearing surfaces 105 of rings 101 and 103, and the bearing surfaces 105 of rings 102 and 104, said spaces affording support for a plurality of bearings 110 located therebetween. For the purposes of the present invention, the term bearing, when used as a noun, is defined as an element that rolls between two races of a slewing ring, for example a ball.
The bearings 110 roll adjacent to and in between the bearing surface 105 of rings 101 and 103, and the bearing surfaces 105 of rings 102 and 104, and reduce friction between components rotating about the axis 5 and coupled to the slewing ring 10. For illustrative purposes only, the bearings 110 shown in the figures are in the form of ball bearings, however any type of bearing can be used in the present invention including roller bearings, needle roller bearings, tapered roller bearings and spherical roller bearings. For the purposes of the present invention, ball bearings are bearings in the form of spheres, roller bearings are bearings in the form of cylinders with a slightly greater length than diameter, needle roller bearings are bearings in the form of long and thin cylinders, tapered roller bearings are bearings in the form conical rollers, and spherical roller bearings are bearings in the form of rollers that are thicker in the middle and thinner at the ends.
The inner race 12 and the outer race 14 can each include additional apertures, bores and/or pins, as illustratively shown by the positioning pin 6 in
The invention has been described in an illustrative manner. It is, therefore, to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Thus, within the scope of the appended claims, the invention may be practiced other than as specifically described.
This application claims priority of U.S. Provisional Patent Application Ser. No. 60/738,959 filed Nov. 22, 2005, which is incorporated herein by reference.
Number | Date | Country | |
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60738959 | Nov 2005 | US |