Roller and ball bearing bearing isolator

Abstract: A bearing isolator assembly (70) suitable for use with straight roller and with ball bearings (20) is provided. The bearing isolator assembly comprises a retaining member (72), a radial wave spring (74), and a nonresilient bump stop member (130), all preferably of a one-piece steel construction.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to bearing isolators for mounting roller and/or ball bearings to supporting structures to isolate the supporting structures from the primarily radial vibrations and oscillations that the bearings, and the shafts rotatably supported thereby, are subject to. More particularly, this invention relates to isolators utilized in connection with roller and/or ball bearings rotatably supporting torque transmitting shafts in vehicular mechanical change gear transmissions. Resilient, flexible and/or cushioned bearing mounts or isolators utilized to isolate a support member from the vibrations and oscillations to which a bearing and the rotatably supported member, most often a shaft of some type, is subject to are, of course, well known in the prior art. Examples of such prior art devices may be seen by reference to United States patents Nos. 2,733,108; 3,309,154; 3,385,543; 3,709,570; 4,422,780 and 4,825,718. Vehicular drivetrain components such as drive axles and mechanical change gear transmissions which utilize bearings, included ball and roller bearings, to rotatably support torque transmitting members, usually comprising some type of shafts; in a housing are well known in the prior art as may be seen by reference to United States Patents Nos. 4,788,889; 4,754,665; 4,736,643; 4,735,109; 4,709,590; 4,373,403; 4,761,867 and 4,678,017. The use of bearing isolators and/or of cushioned, resilient and/or flexible bearing mounts in drivetrain components to isolate the drive train component housing from shaft and gear vibrations and oscillations to reduce wear, to dampen the vibrations or oscillations, to increase vehicular occupant comfort and/or to minimize drive train noise is known. However, the previous resilient bearing mounts/bearing isolators were not totally satisfactory as the prior art devices were complicated and/or expensive to manufacture and/or assemble and/or utilized rubber and/or other nonmetallic materials which were expensive, not totally elastic, of an improper spring rate, not long wearing, and/or excessively sensitive to temperature and lubricants and/or did not limit deflection and stress of the resilient members. DE-C-934 447 discloses a retaining ring which fits in semicircular grooves in a wave spring and the inner wall of a housing, to give a measure of axial retention. GB-A-1 091 809 represents the state of the art, and discloses the pre-characterizing portion of Claim 1, but its proposal lacks a positive stop to excessive radial excursions of such a radially waved spring. SUMMARY OF THE INVENTION In accordance with the present invention, the drawbacks of the prior art have been minimized or overcome by the provision of a new and improved relatively simple, inexpensive all metallic bearing isolator for ball and roller bearings. The above is accomplished by Claim 1, embodiments thereof providing a bearing isolator comprising amongst others two principal components, which are all metallic (preferably of a suitable steel) and of a relatively simple and inexpensively produced structure. The principal components of the isolator embodiment of the present invention include (i) an annular, flanged wear ring/retainer sleeve for receipt in the bearing support apertures of the housing support walls, (ii) a generally tubular shaped radial wave spring which is resiliently radially deformable and is resiliently radially deformed between the inner diameter of the retainer and the outer diameter of the retained bearing outer race and (iii) a bump stop which limits travel and stress of the radial wave spring. Preferably, the radial wave springs are made of a spring steel, such as for example SAE 6150 or the like, while the retainer and wear rings are made of a standard gear or shaft steel, such as SAE 1010, 1018 or 1020 or the like and are preferably surface hardened. Accordingly, it is an object of the present invention to provide a new and improved bearing isolator which is of a relatively simple, preferably all metallic, construction and which is suitable for use with ball and straight roller bearings. This and other objects and advantages of the present invention will become apparent from a reading of the detailed description of the preferred embodiment taken in connection with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial sectional view of a vehicular transmission utilizing the bearing isolators of the present invention. Figure 1A is a schematic illustration of a typical change gear transmission as illustrated in Figure 1. Figure 2 is a sectional view of the retainer portion of the bearing isolator of the present invention. Figure 3 is an elevational view of a radial wave spring member of the bearing isolator of the present invention. Figure 4 is a side view, in section, of the radial wave spring illustrated in Figure 3. DESCRIPTION OF THE PREFERRED EMBODIMENT In this disclosure, certain terminology will be used for convenience and reference only and will not be limiting. For example, the terms "forward" and "rearward" will refer to directions forward and rearward of the transmission as normally mounted in a vehicle. The terms "rightward" and "leftward" will refer to directions in the drawings in connection with which the terminology is used. The terms "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the apparatus being described. The terms "upward" and "downward" will refer to directions taken in the drawings in connection with which the terminology is used. All of the foregoing terms include the normal derivatives and equivalents thereof. A typical change gear transmission or transmission section 10 with which the bearing isolator assembly or the present invention may be advantageous utilized may be seen by reference to Figures 1 and 1A. Transmission 10 is a simple transmission, or transmission section, of the twin countershaft type which is well known in the prior art and which may be understood in greater detail by reference to U.S. patent Nos. 3,105,395; 3,611,823; 4,152,949; 4,445,393 and 4,194,410. The illustrated transmission 10 comprises an input shaft 14 carrying an input gear 16 for rotation therewith. The input shaft 14 is intended to be driven by a prime mover (not shown) through a master clutch or torque converter (not shown) as is well known in the art. A pair of substantially identical countershafts 18 and 18A are rotatably mounted in the housing by means of straight roller bearings 20 and 20A. A main or output shaft 22 is provided which is preferably floatingly and/or pivotably mounted in the transmission housing H. Each of the countershafts 18 and 18A carry countershaft gears 24, 26, 28, 30 and 32 fixed thereto for rotation therewith. Countershaft gear 24 is constantly meshed with the input gear 16. Third speed main shaft gear 34 surrounds main shaft 22 and is constantly meshed with and supported by the countershaft gears 26. Second speed mainshaft gear 36 surrounds mainshaft 22 and is constantly meshed with and supported by countershaft gear 28. First speed mainshaft gear 38 surrounds mainshaft 22 and is constantly meshed and supported by the countershaft gears 30. The reverse mainshaft gear 40 surrounds mainshaft 22, and is constantly meshed with and supported by a pair of idler gears (not shown) which, in turn, are constantly meshed with and driven by the countershaft gears 32. Preferably, as is well known in the art, mainshaft gears 34, 36, 38 and 40 are radially movable relative to mainshaft 22. The advantages of utilizing a floating mainshaft 22 and/or floating mainshaft gears are well known in the art and may be appreciated in greater detail by the aforementioned U.S. patent No. 3,105,395. Axially slidable jaw clutches 42, 44 and 46 are mounted, preferably by a splined connection, to mainshaft 22 for axial sliding movement relative thereto, and for rotation therewith. Clutch 42 may be moved to the left from the neutral position shown to selectably couple the mainshaft 22 directly to the input gear 16 and input shaft 14 for fourth or direct drive of transmission 10, or moved rightwardly from the position shown to engage mainshaft gear 34 with mainshaft 22 for third speed operation of transmission 10. Clutch 44 may be moved from the position shown leftwardly to engage mainshaft gear 36 with mainshaft 22 for second speed operation or may be moved rightwardly from the position shown to engage mainshaft gear 38 with mainshaft 22 for first speed operation of transmission 10. Clutch 46 may be moved rightwardly from the neutral position shown to engage mainshaft gear 40 with mainshaft 22 for reverse operation of transmission 10. Of course, clutches 42, 44 and 46 may be positive clutches, friction clutches, lock clutches and/or synchronized clutches. A shift fork or yoke 48 is received in a groove in clutch 42 for controlling the axial position of clutch 42 relative to mainshaft 22. A shift fork 50 is received in a groove in clutch 44 for axially controlling the position of clutch 44 relative to mainshaft 22. A shift fork 52 is received in an axial groove in clutch 46 for controlling the axial position of clutch 46 relative to mainshaft 22. As is known, the axial positioning of the shift forks is controlled by a shift bar housing assembly or the like. As indicated above, countershaft 18 and the gears rotatably secured thereto are substantially identical to countershaft 18A and the gears rotatably associated therewith. Accordingly, only the rotational support of the axially rear end of countershaft 18 in housing H will be described in detail herein with the understanding that the rotational support of the forward end of countershaft 18 and of countershaft 18A is substantially structurally and functional identical thereto. As may be seen in greater detail by reference to Figure 1, the axially rear end of countershaft 18 is rotatably supported in housing H by means of straight roller bearing 20, which, with the possible exception of a size difference, is substantially functionally and structurally identical with the forward roller bearings and of a well known prior art construction. Briefly, each of the roller bearings includes an inner race 54 adapted to be snugly received on a reduced diameter portion 56 of the countershaft 18, an outer race 58 adapted to be snugly received within a bore 60 of the support housing H and a plurality of rollers 62 each rotatable about an axis substantially parallel to the common axis 64 of the shaft 18 and the inner and outer races of the bearing. The outer bearing race defines an outer diameter surface 59 directly or indirectly mounted in bore or aperture 60 and also defines an axially outwardly facing surface 61. In a typical installation, countershaft 18 will include an axially outwardly facing shoulder 65 which will cooperate with an axially inwardly facing surface 66 provided on the inner race 54 of the bearing, in combination with snap ring 67 received on the outer end of shaft 18, to axially position the shaft relative to bearing 20. The bearing isolator assembly 70 of the present invention is comprised of three main components, namely a retainer member 72, a radial wave spring member 74 and a bump stop member 130. Preferably, for purposes of simplicity of machining, minimization of material costs and improved resistance to wear and temperature and lubricant damage, preferably the retainer 72 and the wear ring are made of a suitable surface hardened steel material, such as SAE 1018-1029 steel, for example, while the radial wave spring 74 is of a suitable spring steel such as, for example, SAE 6150 steel. As may be seen in greater detail by reference to Figure 2, the retainer 72 is of a generally tubular shape having a radially outwardly extending flange 80 at one axial end thereof and a radially inwardly extending flange 82 at the opposite axial end thereof. The generally tubular intermediate portion 84 of the retaining member has an outer diameter 86 generally equal to the inner diameter of the bearing receiving aperture 60 provided in the housing and is axially retained in the housing by means of flange 80 interacting with a shoulder 90 provided in the housing. Such an outwardly extending flange 80 for axial retention is in itself known from DE-A-1 625 518 or US-A-3 749 463. A radial wave spring 74, see Figure 3 and Figure 4, is telescopically received within the tubular body portion 84 of the retainer member and defines a major or maximum outer diameter 92 which is slightly less than or equal to the inner diameter 94 of the tubular portion 84 of the retaining member 72. The radial wave spring 74 also defines a minor or minimum inner diameter 96 which is greater than the inner diameter 98 defined by inwardly extending flange portion 82 of the retainer 72. The radial wave spring 74 is designed to be received in a press fit relationship on the outer diameter of the outer bearing race 58 of the bearings 20 as may be seen by reference to Figure 1. Further, the inner diameter 98 defined by the inwardly extending flange 82 of the retainer is less than the outer diameter 92 of the radial wave spring and thus the radial wave spring is axially retained relative to the housing H by the retaining member 72. The diameter 98 of flange 82 is less than the outer diameter of the outer bearing race 58 so the bearing is retained axially by the retaining member 72. Referring specifically to Figures 3 and 4, it may be seen, that the radial wave spring member 74 is a generally tubular member with a substantially constant cross sectional radial wall thickness 100. The radial outer diameter varies from a major or maximum value 92 to a minor or minimum value 102, and the radial inner diameter varies from a minor or minimum value 96 to a major or maximum value 104, in a substantially periodic smoothly and continuous manner with the maximums and minimums occurring at at least three generally equally spaced circumferentially spaced locations. As the radial wave spring is of a spring steel, it is substantially resiliently deformable with no plastic deformation to allow a predetermined amount of resilient radial movement of the rotational axis 64 of the bearings 20 and the shaft 18 rotatably supported thereby. As the radial wall thickness 100 of the radial wave spring is substantially constant, the major outer and inner diameters, and the minor outer and inner diameters, will occur at the same circumferential position about the generally tubular radial wave spring. Preferably, the difference in magnitude between the major and minor outer diameters, and between the major and minor inner diameters, will be in the range of 0.1% to 50.0% of the mean values thereof. At the rearward or rightward end of the transmission 10, a bearing cover member 128 interacts with housing H to retain the bearing isolator assembly 70 and bearing 20 in the housing H. A steel ring 130 may be used to provide positive radial stop for, bearing 20. Ring 130 is axially interposed between the inwardly extending flange 82 of retainer 72 and the radial wave spring 74. Preferably, the radial spring rate of the wave spring is in range of 10.0% to 150.0% of the radial spring rate of bearing 20. Accordingly, it may be seen, that a relatively simple and inexpensive bearing isolator assembly, preferably comprised of all steel components, and which will dampen and/or isolate radial vibrations and is thus suitable for use with straight roller and ball bearings, has been provided.

Claims: A bearing isolator assembly (70) in which a bearing (20) of the type comprising a radially inner race (54), a radially outer race (58) and a plurality of rotating members (62) are mounted to a housing (H) having an aperture (60) defining an inner diameter surface (57) for receipt of said bearings, said outer bearing race defining an outer diameter surface (59), said bearing isolator assembly comprising: a generally tubularly shaped radial wave spring (74) telescopically received on at least a portion of said outer bearing race outer diameter surface and radially interposed between said outer diameter surface and the inner diameter surface of said aperture, and a retaining member (72); wherein, said retaining member comprises a generally tubular shaped intermediate portion (84) having an inner diameter (94) generally equal to the largest outer diameter (92) of said radial wave spring, and an outer diameter (86) generally equal to the inner diameter of said aperture (60) in said housing; and a radially inwardly extending flanged portion (82) extends at the axially inward end thereof, said radially inwardly extending flanged portion (82) having an inner diameter (98) smaller than the outer diameter (59) of said bearing (20); characterized in that, a radially outwardly extending flanged portion (80) extends at the axially outer end thereof and a substantially nondeformable bump stop member (130) is received in said retaining member (72) for defining a maximum radial movement of said outer bearing race (58) relative to said retaining member. The isolator assembly of claim 1 wherein said radial wave spring defines a minimum inner diameter (96) less than the outer diameter of said outer bearing race. The bearing isolator assembly of claims 1 or 2 wherein said radial wave spring is of a spring steel material. The bearing isolator assembly of claims 1 or 2 or 3, wherein said radial wave spring (74) comprises a generally tubular member having a substantially constant radial wall thickness (100) in cross section and having an outer diameter surface defining a radial outer diameter substantially smoothly continuously and periodically varying from a maximum value (92) to a minimal value (102) at least three substantially equally circumferentially spaced locations about the circumference of said outer diameter. The bearing isolator assembly of claim 1 or 2 wherein said retaining member is of a medium steel material. The bearing isolator assembly of claim 4 wherein the difference between said maximum and minimum outer diameters is in the range of 0.1% to 50.0% of the mean outer diameter.

Inventors: BAIR JOHN JOSEPH, BRAUN EUGENE RALPH, DAMON GERALD DOUGLAS, BAIR, JOHN JOSEPH, BRAUN, EUGENE RALPH, DAMON, GERALD DOUGLAS
Applicants: EATON CORP, EATON CORPORATION
Application year: 1991
Main classification: F16C27
IPC codes: F16C35, F16C27, F16F15