Background of the Invention
1. Field of the Invention
This invention relates generally to bearings, and more specifically to a recirculating ball bearing assembly.
2. Description of the Prior Art
Recirculating ball bearing assemblies are generally well known in the art of which U.S. Pat. Nos. 3,845,993, 3,655,247, 1,750,140 and 1,883,103 are exemplary. U.S. Pat. No. 3,845,993 discloses a recirculating ball bearing assembly comprising a base plate having recessed side surface areas and partial opposed bearing track surfaces on each side surface. The bearing assembly further has a body portion having recessed sides and partial opposed tracks. A guide member with arcuate ends is interposed between the base plate and body portion. Screws secure the base plate, body portion and guide member together so that the partial tracks on the opposed sides of the body portion will in cooperation with the arcuate ends of the guide member serve to form an endless track for a plurality of opposed ball bearings received therewithin. A cover plate is slid over the assembly to prevent the ball bearings from falling out of the endless track. With this recirculating ball bearing assembly, it is desirable that the partial opposed bearing tracks on the base plate and the partial opposed bearing tracks on the body portion align with one another to relatively close tolerances in order to provide a smooth uninterrupted surface for allowing the ball bearings to circulate freely. Accordingly, the body and base portions and the openings extending therethrough for securng the portions together must be manufactured to relative close tolerances.
U.S. Pat. No. 3,655,247 discloses a recirculating bearing having a cylindrical inner race body secured to a body portion by side plates. The body portion has a straight portion and arcuate end portions integrally joined thereto to provide a major portion of an outer race. The cylindrical race body is floatingly mounted on roller members interposed between the inner and outer races. The roller members have an annular radial concave recess centrally thereof to provide adjustability of the race body about its axial centerline.
U.S. Pat. Nos. 1,750,140 and 1,883,103 disclose anti-friction ball bearing assemblies having ball bearing retainer strips or shields. Each retainer strip has a straight portion and arcuate end portions forming a major portion of an outer retainer for the ball bearings.
Summary of the Invention
In accordance with a preferred embodiment of the invention, an improved recirculating ball bearing assembly is disclosed that is of simple design and construction, and economical to manufacture. The bearing assembly comprises a body portion having a recess on at least one side, the periphery of which forms a major portion of an outer race. The body portion further has an opening extending therethrough for receiving an inner race member, at least one side portion of which extends into a recess with the outer periphery thereof forming an endless inner race. The ball bearings are interposed between each inner race and its complementary major portion of the outer race. The ball bearings further surround the inner race to form an endless row of ball bearings.
One of the advantages of the recirculating ball bearing assembly of this invention is that it is of simple design and construction, and economical to manufacture. The number of parts involved in the construction of this bearing assembly are minimal. Another advantage of the recirculating bearing assembly of this invention is that the major portion of the outer race has a smooth uninterrupted peripheral surface comprising a straight portion and integral arcuate end portions, all formed by a unitary body portion. In prior bearing assemblies where the outer race is formed of two or more parts, a problem exists in adequately aligning the major portion of the peripheral surface of the outer race along its entire length to eliminate any interference to free movement of the ball bearings. This problem is eliminated in a bearing assembly of this invention by forming the outer race in a unitary member so that the major portion of the peripheral surface of the outer race along its entire length is smooth and uninterrupted.
The invention and its advantages will become more apparent from the detailed description of the preferred embodiment presented below.
Brief Description of the Drawing
In the detailed description of the preferred embodiment of the invention presented below, reference is made to the accompanying drawing, in which:
FIG. 1 is a perspective view partially broken away showing, in partial schematic fashion, the bearing assembly in place;
FIG. 2 is a section view taken substantially along line 2--2 of FIG. 1;
FIG. 3 is a section view taken substantially along line 3--3 of FIG. 2; and
FIG. 4 is an exploded view showing the various components of the assembly in their relative position with regard to each other.
Detailed Description of the Invention
With reference to FIG. 1 of the drawing, one possible application for the recirculating ball bearing assembly 10 of this invention is disclosed in which the bearing assembly is mounted by any suitable means between two objects 12, 14 for facilitating relative movement between the objects. The objects, for example, could be a grinder or milling machine and a cooperating way. In another possible application, not shown, the bearing assemblies could be incorporated in gibs or plates secured to a housing and arranged to form an opening extending therethrough for slidably supporting a shaft or ram.
With reference to FIGS. 2-4, a preferred embodiment of the recirculating ball bearing assembly 10 of this invention is disclosed comprising a body portion 16 having recesses 18 in opposite sides thereof terminating in base surfaces 19. The periphery of each of the recesses 18 forms a major portion of an outer race comprising a straight peripheral surface portion 20 and integral arcuate peripheral end surface portions 22, both of which are smooth and uninterrupted along their entire length. The body portion 16 further has an elongated opening 24 (FIG. 4) extended therethrough parallel to a bottom surface 26 and spaced therefrom to define a body plate 25. An elongated inner race plate 28 having arcuate ends 30 is insertable through opening 24 with side portions 32 thereof extending into recesses 18 as best seen in FIG. 2. The body portion 16 and inner race plate 28 are secured together by two or more screws 34 as best illustrated in FIGS. 2 and 4. The screws 34 extend through openings 35, 37 respectively in body portion 16 and inner race plate 28 and thread into complementary openings in body plate 25. Openings 37 can be enlarged or elongated to allow some adjustability of plate 28 relative to body portion 16, if desired.
The outer periphery 33 of each of the side portions 32 of inner race plate 28 forms an endless inner race for an endless row of ball bearings 36. Since the peripheral surface 33 of each inner race and complementary major portion of the outer race (surfaces 20 and 22) are smooth, uninterrupted continuous surfaces, each row of ball bearings 36 are free to circulate without binding or catching. Each endless row of ball bearing 36, as best seen in FIG. 3, is retained around its complementary inner race plate 28 by a U-shaped cover plate (FIGS. 2 and 4) having a base 40, depending legs 42 coacting with the base surfaces 19 of recesses 18 for laterally confining ball bearings 36 and turned in ribs 44 at the ends thereof for preventing a lower reach 45 of ball bearings 36 from falling out of the bearing assembly 10. Each lower reach 45 of ball bearings 36 extends past flat bottom surface 26 for slidably engaging a flat surface 46 of lower object 14. The flat surface 46 of object 14, in effect, forms a minor portion of the outer race for the lower reach of ball bearings 36.
The invention has been described in detail with particular reference to a preferred embodiment, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described.