Patent Document

TECHNICAL FIELD  
       [0001]     The present invention relates generally to tools and processes for deep rolling elongate work pieces such as crankshafts and camshafts, and relates more particularly to a lower tool for deep rolling having a plug-in mounting arrangement in a housing.  
       BACKGROUND OF THE INVENTION  
       [0002]     Deep rolling apparatuses and deep rolling systems have been known in the art for many years. Prior art deep rolling systems generally use a lower tool in conjunction with an upper tool to deep roll compressive stresses into a crankshaft, for use in vehicles and other applications, increasing the strength around lobes or cams on the crankshaft. The need for deep rolling is becoming ever more important because automotive vehicles and components are being downsized to reduce weight and improve fuel efficiency; accordingly, smaller engines and crankshafts are increasingly needed. With smaller engines and crankshafts, made with less material than older, more robust designs, there is a need to improve the crankshaft&#39;s fatigue strength and durability. This improved fatigue strength and durability is accomplished through deep rolling of the fillets or lobes and other circular joint areas along the crankshaft. The strength and durability of crank pins of the main bearing journals can be significantly increased by forming compressive stresses into the annular fillets between the pin journals and the adjacent counter weights, or balancing webs on the crankshaft.  
         [0003]     Some prior art lower tools use a system of rollers to support and roll the crankshaft while the upper tool employs work rolls that actually do the strengthening and finishing of the work piece. Other types of lower work tools also include work rolls which assist in forming the compressive stresses, along with the upper tool. In such a design, back up rollers operate to rotatably support the work rolls, which are held in place by a cage retainer and cage.  
         [0004]     Relatively high mechanical forces are necessary to sufficiently compress/stress the work piece. As is well know in the mechanical arts, applications using higher forces tend to cause moving parts to wear out relatively more quickly than in designs using more modest forces. In a typical deep rolling operation, the work rolls and support rollers are encased in a modular tool that is supported in a housing. When servicing of any of the tool components is necessary, processing is stopped and the tools are disassembled from their respective housings for servicing and/or replacement. Accordingly, this halt in production has associated expenses relating to process down time, and is relatively labor intensive.  
         [0005]     Therefore, there is a need in the art for a faster and easier way to replace or repair deep rolling tools.  
       SUMMARY OF THE INVENTION  
       [0006]     It is one object of the present invention to provide a novel design for a removable deep rolling tool.  
         [0007]     Another object of the present invention is to provide for relatively quick and easy installation and removal of rollers used to support a work piece in a deep rolling apparatus.  
         [0008]     In accordance with the forgoing and other objects, the present invention provides a novel deep rolling tool design employing a spring detent mounted in a housing that positions and supports a deep rolling tool, providing for plug-in mounting of the tool therein. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an end view of a lower tool and work piece according to the present invention;  
         [0010]      FIG. 2  is a partial sectioned view taken along line  2 - 2  of  FIG. 2 ;  
         [0011]      FIG. 3  is a partial perspective view of the plug-in lower tool of  FIG. 1 ;  
         [0012]      FIG. 4  is a positioning member for a deep rolling tool according to the present invention;  
         [0013]      FIG. 5  is an end view of a lower tool and work piece according to the present invention;  
         [0014]      FIG. 6  is a partial side view of a spring detent mechanism and lower tool according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0015]     Referring to  FIG. 1 , there is shown an end view of a lower tool  10  for deep rolling according to the present invention. Lower tool  10  preferably includes a housing  20  within which a plurality of roller modules or tool casings  12  and  14  are preferably positioned. A work piece “W” is preferably rotatably supported by roller modules  12  and  14 , whereby it can be deep rolled in a conventional manner via an upper tool (“not shown”). In a preferred embodiment, modules  12  and  14  provide a roller mechanism for rotating and supporting the work piece while an upper tool actually performs the compressive pre-stressing work. It should be appreciated, however, that the designs disclosed herein are similarly applicable to deep rolling apparatuses wherein either or both of the upper and lower tools are used to actually modify the work piece. A positioning member  30  is preferably provided, and also mounted in housing  20 . Positioning member  30  assists in appropriately positioning work piece “W” with respect to the upper tool and lower tool  20 . Each of roller modules  12  and  14  preferably includes a roller, denoted with numeral  15  in roller module  12 , rotated beneath work piece W. Each of roller modules  12  and  14  preferably slides into a recessed region or seat  23  in housing  20  that supports roller modules  12  and  14 . In a preferred embodiment, each recessed region  23  preferably comprises a substantially rectangular seat that receives each of the roller modules in a substantially mating fashion. The present description refers largely to only one of the illustrated lower tools  12 , however, those skilled in the art will appreciate that the descriptions herein are similarly applicable to either of the illustrated tools  12  and  14 . In the apparatus illustrated in  FIG. 1 , the various features of housing  20  relating to tools  12  and  14 , e.g. the seat  23  and passage  21  described herein, are preferably substantially mirror images.  
         [0016]     Turning now to  FIG. 5 , there is shown a lower tool apparatus  110  in accordance with the present invention. Apparatus  110  is similar to apparatus  10 , and like numerals are used to identify similar features where appropriate. Thus, apparatus  110  includes first and second roller modules  112  and  114 , mounted in a housing  120 . Spring detents  118  and  119  are provided and allow roller modules  112  and  114  to be plugged in to housing  120 . In one preferred embodiment, a positioning member  130  is provided and equipped with a spring detent mechanism (not shown) similar to those described with respect to modules  112  and  114 .  FIG. 6  illustrates a close up view of spring detent  118 . As illustrated, spring detent  118  comprises a body member having an internal ball  150  and spring  140  mechanism. Spring detent  118  is preferably constructed such that ball  150  may be pushed completely into the body of spring detent  118 , overcoming the bias of spring  140 , but cannot be pushed completely out of engagement therein. Accordingly, a portion of spring detent  118  is preferably mounted within a passage  121  in housing  120 , and is adapted to retain the roller module in housing  120  by urging ball  150  into engagement therewith. In a preferred embodiment, spring detent  118  is threaded into passage  121  to a desired depth in housing  120 . Other means for positioning and retaining spring detent  118  in housing  120  are contemplated, and the description herein of a threaded engagement should not be taken as limiting. A recess  122  may be formed in a head  141  of spring detent  118  that is adapted to receive a screwdriver for threadedly engaging spring detent  118  in passage  121 .  
         [0017]     Roller module  112  preferably includes an extension  116  depending therefrom that preferably includes a shaped detent surface  117  adapted to engage with ball  150 . Spring  140  continually urges ball  150  outwardly, and accordingly, when roller module  112  is placed into housing  120 , extension  116  can be urged past ball  150 , overcoming the force of spring  140 , such that surface  117  is engaged by ball  150 , locking roller module  115  in place. Removal of roller module  115  takes place either by pulling outwardly on the module with sufficient force to overcome the detent action of spring detent  118 , or by backing spring detent  118  outwardly in passage  121  such that ball  150  disengages with extension  116 .  
         [0018]     The preferably threaded engagement of spring detent  118  in housing  120  allows spring detent  118  to be positioned at a carefully selected depth in passage  121 . In particular, the spring detent  118  can be positioned such that ball  150  is extensible by spring  140  a desired distance past an inner end  122  of passage  121 . Accordingly, the relative ease with which engagement between ball  150  and extension  116  may be overcome is adjustable. For example, where it is desirable to manually pull roller module  112  out of housing  120 , spring detent  118  can be rotated a first direction within passage  121  to allow for easier disengagement of ball  150  from extension  116 . Similarly, it can be rotated an opposite direction to provide for relatively tighter retention of roller module  115 . It should be noted that detent  118  may be press fit in orifice  121  or may use any other known mechanical or chemical fastening process. Alternative embodiments are contemplated wherein a spring ball detent is positioned in module  112 , and extends into engagement with a complementary portion of the housing. Further still, rather than a spring detent as described herein, the apparatus might use a simple threaded member that could be alternately extended or retracted from passage  121 , into or out of engagement with the tool.  
         [0019]     Returning to  FIGS. 1-4 , roller modules  12  and  14  are preferably retained in housing  20  via an alternative spring-loaded mechanism. In a preferred embodiment each of roller modules  12  and  14  includes an extension  16  that depends from a lower portion of the roller module. When the roller module  12 ,  14  is positioned in its respective seat  23 , extension  16  is inserted through an aperture  23   a  in communication with seat  23 . A passage  21  is preferably formed in housing  12  and is in communication with aperture  23   a . A reciprocable pin  18  is engaged with and movable relative to extension  16 , and preferably slidable relative thereto to provide for plug-in engagement of roller modules  12  and  14  with housing  20 .  
         [0020]     In  FIG. 3 , there is shown in perspective a portion of a roller module extension  16 , and pin  18  that is slidably engageable therewith. In a preferred embodiment pin  18  comprises first  19   a  and second  19   b  legs, separated by a slot  25 , that slidably engage about a substantially complementary portion of extension  16 . In particular, in one preferred embodiment each of legs  19   a  and  19   b  slide into engagement about extension  16  via channels  17   a  and  17   b  formed therein, preventing relative displacement between pin  18  and module  12  in a direction perpendicular to the direction of sliding of pin  18 . A spring, for example a helical spring, may be positioned within slot  25  of pin  18 , and can bias pin  18  toward an extended position relative to extension  16 . Pin  18  further preferably includes a head  41 , which may have a slot  22  formed therein for engagement by a manual tool, as described herein.  
         [0021]     Pin  18  may preferably be pushed into engagement about extension  16  when module  12  is mounted in housing  20 . One means for pushing pin  18  into the position illustrated in  FIG. 2  is with a tool inserted via an end of passage  21 . In a preferred embodiment, passage  21  comprises a first portion  21   a  having a first diameter and a second portion  21   b  having a second diameter greater than said first diameter. Pin  18  is therefore preferably slidable in passage  21   b  formed in housing  20 , and is urged therein toward an extended position by a spring (not shown). Second passage  21   a  preferably includes a diameter slightly smaller than the diameter of pin  18 , and connects with an outside end of passage  21 , allowing the tool (not shown) to be inserted therein to push pin  18  towards its retracted position. The preferably lesser diameter of the first portion  21   a  prevents pin  18  from being urged completely through passage  21 . In a preferred embodiment, pin  18  thus remains partially about extension  16 , preferably prevented from disengagement therewith via an interface of legs  19   a  and  19   b  with channels  17   a  and  17   b . In the retracted position of pin  18 , roller module  12  may be disengaged from housing  20 . When pin  18  is in the extended position, it resists disengagement of roller module  12  from tool  20  by abutting against the wall of passage  21 .  
         [0022]     The present embodiment of  FIG. 1 , by using slidable pin  18  therefore allows relatively easy engagement and disengagement of roller modules  12  and  14  with housing  20 . When it is desirable to replace or service a worn roller module, for example, a tool can be inserted into passage  21  and used to urge pin  18  to its retracted position at which module  12  may be pulled from housing  20 . In the embodiment of  FIG. 5 , a tool can be inserted into the passage to rotate the spring detent, adjusting the spring detent axially therein with respect to the tool module.  
         [0023]     Turning now to  FIG. 2 , which is a partially sectioned view taken along line  2 - 2  of  FIG. 1 , there are illustrated the preferred internal components of roller module  12  and one preferred geometry of extension  16 . In the  FIG. 2  embodiment, module  12  comprises a main roller  15  that rotates around a backup roller  13 . Thus, in a deep rolling process roller  15  engages with the rotating work piece and is supported by back up roller  13 , which rotates on an axle supported by roller module  12 . Extension  16  extends downwardly from a body portion  12   a  of roller module  12 , and may comprise a substantially I-shaped cross section, as shown in  FIG. 3 . Alternatively, extension  16  can be formed with an annulus extending around the exterior thereof. It should be appreciated that the design of extension  16  and pin  18  is exemplary only, and could be varied significantly without departing from the scope of the present invention. Moreover, pin  18  need not engage with an “extension” at all; rather, tool  12  might be constructed such that pin  18  reciprocates within a bore formed directly in tool  12 , or it might engage with an extension or other feature by means other than that disclosed. Still further embodiments are contemplated wherein pin  18  threadedly engages with the tool or an extension thereon and is “reciprocated” by rotation.  
         [0024]     The present invention thus provides significant advantages over earlier designs wherein the tools were semi-permanently fixed into their respective housings. Utilizing the present invention, it is no longer necessary to take the time consuming steps of disassembling the apparatus to replace or service a worn tool. An operator can readily plug a roller module into its housing, allowing the detent mechanism such as the described spring detent or reciprocable pin to secure the tool therein. To remove the roller module, the tool can be pulled from the housing, as in the embodiment utilizing the spring detent  118 , or it can be readily removed with the aid of a tool, such as in the embodiment utilizing the reciprocable pin  18 . While the present description has focused primarily on applications of the present invention to a particular lower tool design, those skilled in the art will appreciate that various upper and lower tools and related roller systems might benefit through the application of the present invention.  
         [0025]     The present description is thus for illustrative purposes only, and should not be construed to narrow the breadth of the present invention in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the spirit and scope of the invention. Other aspects, features, and advantages will be apparent upon an examination of the attached drawing figures and appended claims.

Technology Category: 7