DRAWN CUP CAM FOLLOWER

CLAIM OF PRIORITY

[0001] This application claims priority to U.S. provisional patent application number 62/618,835 filed January 18, 2018 and U.S. provisional patent application number 62/696,369 filed July 11, 2018, the disclosures of which are incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to cam followers. More particularly, the present invention relates to designs and assembly methods of cam followers with cups drawn from sheet metal.

BACKGROUND OF THE INVENTION

[0003] Many applications for cam followers require high precision and, therefore, are costly to produce. For those applications where high precision is not required, it would be desirable to reduce the costs of manufacture.

[0004] The present invention recognizes and addresses considerations of prior art constructions and methods. SUMMARY OF THE INVENTION

[0005] One embodiment of the present disclosure provides a cam follower including a shaft having a first end, a second end, a first cylindrical portion defining an inner raceway, and an annular shoulder extending radially outwardly from the first end of the shaft. A drawn cup has a first end, a second end, a cylindrical sidewall extending therebetween, an inner surface of the sidewall defining an outer raceway, and a radially inwardly depending flange disposed on the second end of the drawn cup. A plurality of rollers is disposed between the inner raceway and the outer raceway, and each roller is also disposed between the annular shoulder of the shaft and the inwardly depending flange of the drawn cup. The flange of the drawn cup extends radially inwardly beyond a radially outermost portion of each roller, and the annular shoulder extends outwardly beyond an innermost portion of each roller.

[0006] Another embodiment of the present disclosure provides a cam follower having a shaft having a first cylindrical portion having a first diameter and a second cylindrical portion having a second diameter, wherein the first diameter is greater than the second diameter. A drawn cup has a first radially-inwardly depending flange and a second radially-inwardly depending flange, wherein the first portion of the shaft is disposed between the first flange and the second flange.

A plurality of rollers disposed between a cylindrical outer surface of the first portion of the shaft and a cylindrical inner surface of the drawn cup.

[0007] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which;

[0009] Figures 1A and 1B are perspective views of a cam follower in accordance with an embodiment of the present disclosure;

[00010] Figures 2A and 2B are cross-sectional views of the cam follower shown in Figures 1A and 1B, taken along lines 2A-2A and 2B-2B, respectively;

[00011] Figures 3A and 3B are exploded views of the cam follower shown in Figures 1A and 1B;

[00012] Figures 4A and 4B are perspective views of a cam follower in accordance with an alternate embodiment of the present disclosure;

[00013] Figure 5 is a cross-sectional view of the cam follower shown in Figure 4A taken along line 5-5;

[00014] Figures 6A and 6B are exploded views of the cam follower shown in Figures 4A and 4B;

[00015] Figures 7A and 7B are perspective views of a cam follower in accordance with an alternate embodiment of the present disclosure;

[00016] Figure 8 is a cross-sectional view of the cam follower shown in Figure 7B taken along line 8-8;

[00017] Figures 9A and 9B are exploded views of the cam follower shown in Figures 7A and

7B; [00018] Figure 10 is an exploded view of a cam follower in accordance with an alternate embodiment of the present disclosure;

[00019] Figures 11 A and 11B are cross-sectional views of the cam follower shown in Figure 10;

[00020] Figure 12 is a perspective view of a cam follower in accordance with an alternate embodiment of the present disclosure;

[00021] Figure 13 is a cross-sectional view of the cam follower shown in Figure 12, taken along line 13-13;

[00022] Figure 14 is an exploded view of the cam follower shown in Figure 12;

[00023] Figure 15 is a perspective view of a cam follower in accordance with an alternate embodiment of the present disclosure;

[00024] Figure 16 is an exploded view of the cam follower shown in Figure 15; and

[00025] Figures 17 and 17A are a cross-sectional and a partial cross-sectional view of the cam follower shown in Figure 15.

[00026] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention according to the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[00027] Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, not limitation, of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

[00028] Referring now to Figures 1A through 3B, a cam follower 100 in accordance with a preferred embodiment of the present invention includes an outer cup 120 disposed concentrically about a shaft 140, a bearing assembly 150 including a plurality of rollers 152 that is disposed between outer cup 120 and shaft 140, and an annular ring 160 that is disposed in an annular groove 161 formed on shaft 140. As shown, annular ring 160 is preferably a C-clip and serves as an axial stop when inserting shaft 140 into a bore (not shown) of a device to which it is being mounted, as discussed in greater detail below. Preferably, outer cup 120 is formed by a drawing process utilizing sheet metal, and incudes a cylindrical sidewall 122 that extends from its first end 124 to its second end 126. The width of the sidewall 122 can be selected dependent upon the application of the cam follower.

[00029] Cylindrical sidewall 122 of outer cup 120 includes a first inner surface portion 128 and a radially-inwardly depending annular flange 138 disposed at its second end 126, and a first end 124 of outer cup 120 is fully open. An inner perimeter 139 annular flange 138 defines an aperture that is configured to slidably receive a mounting portion 143 of shaft 140 therein when assembling cam roller 100, as discussed in greater detail below.

[00030] As shown, shaft 140 includes a stud portion 145 with a cylindrical outer surface 144 that defines a roller raceway, a mounting portion 143 that is configured to be received in a corresponding bore (not shown) of a device to which the cam follower is to be mounted, and a radially-outwardly extending annular ledge 141 that connects the two portions. As shown, mounting portion 143 includes a threaded outer surface 147 that engages a similarly threaded surface of the corresponding bore for mounting. However, in alternate embodiments, mounting portion 143 need not be threaded as C-clips, a press-fit, etc., can be utilized to mount cam follower 100 to the corresponding device. As shown, shaft 140 also includes a central bore 149 to facilitate lubrication of rollers 152 bearing assembly. Radially extending bores 151 are also provided that are in fluid communication with both central bore 149 and outer surface 144 of stud portion 145. As such, lubrication may be provided to rollers 152 of bearing assembly 150 by way of central bore 149. Additionally, an end portion 161 of central bore 149 of shaft is configured to receive a set screw 170 when mounting cam follower 100 to a device, as discussed below. Preferably, set screw 170 and end portion 165 of shaft 140 are correspondingly threaded and set screw 170 has a hexagonally- shaped recess for receiving a correspondingly shaped tool. An annular groove 161 is also provided in the outer surface of shaft 140 that is configured to receive annular ring 160 therein. Note, although the disclosed embodiment is a full complement assembly, in alternate embodiments a roller cage (not shown) may be utilized to maintain spacing between the rollers to facilitate both lubrication and mounting of cam follower 100.

[00031] As best seen in Figure 2A, bearing assembly 150 includes an outer cup 151 with a cylindrical body portion 157 that extends between a first and a second radially-inwardly depending flange 153 and 155, respectively. As shown, first and second flanges 153 and 155 are configured to retain corresponding ends of each roller 152 from inward motion. As such, the plurality of rollers 152 can be pre-assembled in outer cup 151 prior to mounting bearing assembly on stud portion 145 of shaft 140. Use of a pre-assembled, or“catalog”, bearing facilitates the assembly of cam follower 100, which can lead to reduced manufacturing costs. Preferably, second flange 155 of outer cup 151 extends radially-inwardly beyond the outer perimeter of stud portion 145 of shaft 140, thereby forming an axial stop when sliding bearing assembly 150 onto shaft. As well, second flange 155 of outer cup 151 defines a central aperture 159 to facilitate access to set screw 170 when mounting cam follower 100 to a corresponding device. After mounting, a cap 180 is received in aperture 159 to prevent the entry of debris.

[00032] When assembling cam follower 100, stud portion 145 of shaft 140 is inserted into the open end of bearing assembly 150 that is defined by first flange 153 of outer cup 151. Shaft 140 is insertable into bearing assembly 150 up until the end face of stud portion 145 abuts second flange 155 of outer cup 151. Next, the mounting portion 143 of shaft 140 is inserted into the bore defined by inner perimeter 139 of the outer cup’s annular flange 138. Outer cup 120 is moved axially along shaft 140 until bearing assembly 150 is received within outer cup 120 in a press-fit and annular flange 138 of outer cup 120 abuts annular ledge 141 of shaft 140.

Abutment of both annular flange 138 of outer cup 120 with annular ledge 141 of shaft 140 and second flange 155 of the bearing assembly with the end face of stud portion 345 of shaft 140 maintain bearing assembly 150 and outer cup 120 in the desired axial position on shaft 140.

Next annular ring 160 is mounted in annular groove 161 of shaft 140 to serve as an axial stop when mounting cam follower 100 in the corresponding device. As shown, annular ring 160 does not make contact with annular flange 138 of outer cup 120. Note, in alternate embodiments, an additional outer ring (580 in Figure 12 through 14) may be press-fit onto the outer surface of drawn outer cup 120 of the cam follower 100. The additional outer ring may be used for applications where additional operations such as, but not limited to, hardening, grinding, etc., are desired on the outer surface of the cam follower 100.

[00033] Referring now to Figures 4 A through 6B, a cam follower 200 in accordance with an alternate embodiment of the present invention includes an outer cup 220 disposed concentrically about a shaft 240, a bearing assembly 250 including a plurality of rollers 252 that is disposed between outer cup 220 and shaft 240, a mounting set screw 270 and protective cap 280.

Preferably, outer cup 220 is formed by a drawing process utilizing sheet metal and includes a cylindrical sidewall 122, the width of the which can be selected dependent upon the application of the cam follower.

[00034] Cam follower 200 differs primarily from the embodiment described above with regard to Figures 1A through 3B in that cam follower 200 does not include an annular ring (160 in Figure 1B) that functions as an axial stop when mounting cam follower 200 to a device. As such, cam follower 200 does not include an annular groove (161 in Figure 2 A) for receiving any such annular ring. Rather, in addition to a first annular ledge 241 which serves as an axial stop for outer cup 220, shaft of cam follower 240 includes a second annular ledge 243 which serves as an axial stop when shaft 240 of cam follower 200 is being inserted into a mounting bore of the desired device. All other components and features of cam follower 200 are preferably the same as those of cam follower 100 (Figures 1A and 1B) and, as such, a description thereof is not repeated.

[00035] Referring now to Figures 7 A through 9B, a cam follower 300 in accordance with an alternate embodiment of the present invention includes an outer cup 320 disposed concentrically about a shaft 340, a plurality of rollers 350 that is disposed between outer cup 320 and shaft 340, and an annular ring 360 that is disposed in an annular groove 361 formed on shaft 340. As shown, annular ring 360 is preferably a C-clip and serves as an axial stop when inserting shaft 340 into a bore (not shown) of a device to which it is being mounted, as discussed in greater detail below. Preferably, outer cup 320 is formed by a drawing process and includes a cylindrical sidewall 322, the width which can be selected dependent upon the application of the cam follower. Note, referring to Figures 9A and 9B, an additional outer ring 382 may be press- fit onto the outer surface of drawn outer cup 320 of the cam follower 300. The additional outer ring may be used for applications where additional operations such as, but not limited to, hardening, grinding, etc., are desired on the outer surface of cam follower 300.

[00036] Cylindrical sidewall 322 of outer cup 320 includes a first inner surface portion 328 that defines a roller raceway, and a first and a second radially-inwardly depending annular flange 336 and 338 disposed at its first and second ends 324 and 326, respectively. Prior to assembly, second annular flange 338 has not yet been formed so that second end 326 of outer cup 320 is fully open. After assembly, an inner perimeter 339 of second annular flange 338 defines an aperture that is configured to rotatably receive shaft 340 therein. As well, first annular flange 336 of outer cup 320 defines a central aperture 337 to facilitate access to set screw 370 when mounting cam follower 300 to a corresponding device. After mounting, a cap 380 is received in aperture 337 to prevent the entry of debris.

[00037] As shown, shaft 340 includes a stud portion 345 with a cylindrical outer surface 344 that defines a roller raceway, a mounting portion 343 that is configured to be received in a corresponding bore (not shown) of a device to which the cam follower is to be mounted, and a radially-outwardly extending annular ledge 341 that connects the two portions. As shown, mounting portion 343 includes a threaded outer surface 347 that engages a similarly threaded surface of the corresponding bore for mounting. However, in alternate embodiments, mounting portion 343 need not be threaded as C-clips, a press-fit, etc., can be utilized to mount cam follower 300 to the corresponding device. As shown, shaft 340 also includes a central bore 349 and a radially extending bores 351 to facilitate lubrication of rollers 352 of bearing assembly. Additionally, an end portion 365 of central bore 349 of shaft is configured to receive a set screw 370 when mounting cam follower 300 to a device, as discussed below. Preferably, set screw 370 and end portion 365 of shaft 365 are correspondingly threaded. Note, although the disclosed embodiment is a full complement assembly, in alternate embodiments a roller cage (not shown) maybe utilized to maintain spacing between the rollers to facilitate both lubrication and mounting of cam follower 300. As well, first annular flange 356 of outer cup 320 defines a central aperture 357 to facilitate access to set screw 370 when mounting cam follower 300 to a corresponding device. After mounting, a cap 380 is received in aperture 337 to prevent the entry of debris.

[00038] When assembling cam follower 300, stud portion 345 of shaft 340 is inserted into the open second end 326 of outer cup 320 that exists prior to forming second annular flange 338 of outer cup 320. Shaft 340 is insertable into outer cup 320 up until the end face of stud portion 345 abuts first annular flange 336 of outer cup 120. Next, rollers 350 are disposed in the annular space defined between stud portion 345 of shaft 340 and outer cup 320. With rollers 350 inserted, second annular flange 338 of outer cup 320 is curled radially-inwardly until second annular flange 338 of outer cup 320 abuts annular ledge 341 of shaft 340. Abutment of both second annular flange 338 of outer cup 320 with annular ledge 341 of shaft 340 and first annular flange 336 of outer cup 320 with the end face of stud portion 345 of shaft 340 maintains outer cup 320 in the desired axial position on shaft 340. Next annular ring 360 is mounted in annular groove 361 of shaft 340 to serve as an axial stop when mounting cam follower 300 in the corresponding device. As shown, annular ring 360 does not make contact with annular flange 338 of outer cup 320.

[00039] Referring now to Figures 10 through 11B, a cam follower 400 in accordance with an alternate embodiment of the present invention includes an outer cup 420 disposed concentrically about a shaft 440, a plurality of rollers 450 that is disposed between outer cup 420 and shaft 440, an annular ring 460 that is disposed in an annular groove 461 formed on shaft 440, a mounting set screw 470, a protective cap 480 and an annular seal 490. As shown, annular ring 460 is preferably a C-clip and serves as an axial stop when inserting shaft 440 into a bore (not shown) of a device to which it is being mounted. Preferably, outer cup 420 is formed by a drawing process utilizing sheet metal and includes a cylindrical sidewall 422, the width which can be selected dependent upon the application of the cam follower. The primary difference between cam follower 400 and cam follower 300 discussed above (Figures 7A-9B) is the inclusion of annular seal 490. As best seen in Figures 11A andl 1B, annular seal 490 includes an outer surface 492 that is disposed adjacent an inner, circular perimeter 439 defined by flange 438 of outer cup 420, and an annular sealing surface 494 that is in contact with a portion of the outer surfaces of shaft 440 that is between stud portion 445 and annular groove 461 of shaft 440. Annular seal 490 and protective cap 480 help prevent debris from entering outer cup 420, thereby protecting rollers 450. Note, although not shown in Figures 10 through 11B, in alternate embodiments an additional outer ring (382 in Figures 9A and 9B) may be press-fit onto the outer surface of drawn outer cup 420 of the cam follower 400. The additional outer ring may be used for applications where additional operations such as, but not limited to, hardening, grinding, etc., are desired on the outer surface of the cam follower 400.

[00040] Referring now to Figures 12 through 14, a cam follower 500 in accordance with an alternate embodiment of the present invention includes an outer cup 520 disposed concentrically about an inner ring 540, a plurality of rollers 550 that is disposed between outer cup 520 and inner ring 540, and preferably an outer ring 580 that is received on the outer surface of outer cup 520. Preferably, outer cup 520 is formed by a drawing process and includes a cylindrical sidewall 522, the width which can be selected dependent upon the application of the cam follower. The additional outer ring 580 is preferably press-fit onto the outer surface of drawn outer cup 520 of the cam follower 500. The additional outer ring may be used for applications where additional operations such as, but not limited to, hardening, grinding, etc., are desired on the outer surface of the cam follower 500. As well, inner ring 540 is preferably formed by a drawing process utilizing sheet metal and can be installed on a corresponding shaft (not shown ) in a press-fit. Alternatively, inner ring 540 may be axially positioned on a shaft by C-clips, staking, etc.

[00041] Cylindrical sidewall 522 of outer cup 520 includes a first inner surface portion 528 that defines a roller raceway, and a first and a second radially-inwardly depending annular flange 536 and 538 disposed at its first and second ends 524 and 526, respectively. Prior to assembly, first annular flange 536 defines a circular inner perimeter 537 having a diameter that is less than an outer diameter of inner ring 540, and second annular flange 538 has not yet been formed so that second end 526 of outer cup 520 is fully open. After assembly, an inner perimeter 539 of second annular flange 538 defines an aperture that is configured to abut a corresponding end face of inner ring 540, thereby retaining inner ring 540 between first and second annular flange 536 and 538, respectively, of outer cup 520.

[00042] Referring now to Figures 15 through 17, a cam follower 600 in accordance with an alternate embodiment of the present invention includes an outer cup 620 disposed concentrically about a shaft 640, a plurality of rollers 650 disposed between outer cup 620 and shaft 640, and an annular washer 660 disposed between outer cup 620 and shaft 640. As shown, annular washer 660 both axially retains outer cup 620 on shaft 640 and seals an open end of outer cup 620, as discussed in greater detail below. Preferably, outer cup 620 is formed by a drawing process, and includes a cylindrical sidewall 622 that extends from its first end 624 to its second end 626. The width of sidewall 622 can be selected dependent upon the application of the cam follower.

[00043] Cylindrical sidewall 622 includes a first inner surface portion 628 that defines a roller raceway, a second inner surface portion 630, and an annular ledge 636 that extends

therebetween, as best seen in Figure 17A. As shown, the first and second inner surface portions 628 and 630 are concentric about a longitudinal center axis 612 of shaft 640, whereas annular ledge 636 is transverse to the longitudinal center axis of shaft 640. Additionally, outer cup 620 includes a radially-inwardly depending annular flange 638 disposed at its second end 626 and an end wall 632 disposed at its first end 624. Annular lip 638, in combination with both an annular shoulder 646 on a shaft and annular washer 660, is used to axially retain outer cup 620 on shaft 640, whereas end wall 632 preferably creates a lubrication reservoir 639 for the bearing.

Preferably, end wall 632 of outer cup 620 includes a convex inner surface 634 to facilitate the reduction of friction between end wall 632 and an end face 643 of shaft 640.

[00044] As shown, shaft 640 includes a first end with a cylindrical outer surface 644 that defines a roller raceway and an annular shoulder 646 that extends radially-outwardly from outer surface 644 at first end 624 of shaft 640. A second end of shaft 640 defines a mounting portion 643 that is inserted in a corresponding bore (not shown) of a device for mounting cam follower 600 thereto. Mounting portion 643 may include a threaded outer surface, annular groove for receiving a C-clip, etc., for mounting the cam follower to the device. Note, although the disclosed embodiment is a full complement assembly, in alternate embodiments a roller cage (not shown) may be utilized to maintain spacing between the rollers. Similarly to some of the previously discussed embodiments, shaft 640 of cam follower may include a central bore (149 in Figure 2A) to facilitate both lubrication and mounting of cam follower 600. [00045] Preferably, as best seen in Figure 17A, annular washer 660 includes an annular seal 664 and a stiffening rib 662 disposed therein. Annular washer 660 is secured adjacent annular ledge 636 of outer cup 620 by annular lip 638. Specifically, after annular washer 660 is positioned adjacent annular ledge 636, subsequently to rollers 650 being disposed between roller raceways 628 and 644, annular flange 638 is curled radially inwardly so that annular washer 660 is axially retained between annular ledge 636 and annular lip 638. As shown in Figure 17, once assembled, a first end 652 of each roller 650 abuts annular washer 660, whereas a second end 654 of each roller 650 abuts shoulder 646 of shaft 640, thereby axially retaining outer cup 620 on shaft 640. As such, thrust loading on outer cup 620 acts on annular washer 660 by way of annular lip 638. As shown, annular seal 664 preferably includes a pair of annular sealing surfaces 664a and 664b that both are in contact with roller raceway 644. Note, in alternate embodiments, annular seal 664 of annular washer 660 may be omitted, depending upon the method of lubrication that is selected for cam follower 600. As well, in other alternate embodiments, outer cup 620 may be axially secured to annular washer 660 without the use of annular lip 638. For example, annular washer 660 may be received adjacent annular ledge 636 by a press-fit, by staking, by utilizing corresponding threads formed on the outer cup and annular washer, etc.

[00046] While one or more preferred embodiments of the invention are described above, it should be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit thereof. Additionally, the vibration isolator may be constructed of any material found to be suitable for the intended purpose. It is intended that the present invention cover such modifications and variations as come within the scope and spirit of the appended claims and their equivalents.