Patent Publication Number: US-2017368665-A1

Title: Mask for use with particle impact processes and methods of use thereof

Description:
TECHNICAL FIELD 
     Aspects of the disclosure relate generally to the field of vehicle parts and manufacture, and particularly to a mask for use with particle impact processes applied to gears and gear teeth, and methods of use thereof. 
     BACKGROUND 
     It is known in the related art to mask or otherwise protect surfaces to which a particle impact process, such as a shot peen process, is to be applied. Such masking may be time consuming and/or challenging to apply, especially when masking complicated shapes and/or many separate surfaces. In the related art for applying a shot peen process to gear teeth, it is known to radius tooth tips/edges prior to the shot peen process being carried out, so as to prevent bulge in the tooth tips and/or to chamfer the gear teeth after the shot peen process is completed. 
     There remains an unmet need in the art for masking gear teeth edges when applying a shot peen process. 
     SUMMARY 
     Aspects of the present disclosure relate generally to the field of vehicle parts and manufacture, and particularly to a mask for use with a particle impacting process, such as a shot peen process, for spiral and other gears, and methods of use thereof. Such gears may, for example, be used in differentials, transfer units, or drive shafts (e.g., 4wd applications) for vehicles, as well as other applications, such as in power take off (PTO) applications. Such vehicles may include, for example, 2-door/4-door passenger cars (two seat, four seat, etc), pickup trucks, vans, aircraft, multipurpose utility vehicles (MUV), or side-by-side all-terrain vehicles, and the like. The shot peen process may be used, for example, in hardening surfaces of such parts and preventing cracks and other imperfections and/or damage. Suitable shot may include, for example, spherical steel shot, ceramic shot, glass shot, or shot of other material, with each shot having a diameter, for example, of between about 0.1 mm and 1 mm. For example, suitable shot may have a 0.8 mm diameter or a 0.15 mm diameter. 
     During the manufacturing process of hard shot peening gears, for example, it is known that the gear tooth edges, when hit by the hard shot media, may deform and cause a positive material (also interchangeably referred to herein as a “bulge” condition) along the tooth edge. Among other problems, such bulges may result in an unsmooth running condition of gears, creating noise and vibration within the gear system. 
     Aspects of the present disclosure relate to a cover (also interchangeably referred to herein as a “mask”) that protects the edges of the gear teeth during application of the shot peen or other similar process, such as sand or glass bead blasting (such processes interchangeably referred to herein as “particle impacting processes”), without preventing the particle impacting process from effectuating advantageous hardening and other results for areas that are not protected by the mask. The cover may be removable and reusable. Among other advantages, application of the mask may prevent a bulge condition on the tooth tips and/or edges that may otherwise result from the particle impacting process. Among yet other advantages, by protecting the gear tooth tips, a post shot peen process used in the related art for removing resulting bulges may be eliminated. 
     In one example implementation, a protective mask for use, for example, for shot peening a gear, in accordance with aspects of the present disclosure, may have a shape designed for receiving and covering the gear teeth on a gear head, with first and second end ring shaped portions being located at the mask ends, a first end ring portion being closed and a second ring portion being open for receiving the gear head. Between the end portions may be protective vanes, the protective vanes being positionable so as to follow the shape of edges of the gear teeth. 
     In some example implementations, for example, the protective mask may be usable with a generally partial conical overall shaped gear (e.g., a spiral bevel gear), and the protective mask for such use, for example, may likewise have a generally partial overall conical shape corresponding thereto, with first and second end ring shaped portions being located at the mask ends, a first, smaller end ring portion being closed and a second, larger end ring portion being open for receiving the gear within the mask. Between the end portions may be complexly shaped protective vanes, shaped so as to follow the shape of edges of the gear teeth. 
     Additional advantages and novel features of these aspects will be set forth in part in the description that follows, and in part will become more apparent to those skilled in the art upon examination of the following or upon learning by practice of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more example aspects of the present disclosure and, together with the detailed description, serve to explain their principles and implementations. 
         FIG. 1  shows an example spiral bevel gear for use in accordance with aspects of the present invention. 
         FIG. 2  shows a perspective of an example mask in accordance with aspects of the present disclosure. 
         FIG. 3  shows an end view of the example mask of  FIG. 2 , viewed from a first end. 
         FIG. 4  shows an end view of the example mask of  FIG. 2 , viewed from a second end. 
         FIG. 5  shows a representative cross-sectional view of the example mask of  FIG. 2 . 
         FIG. 6  shows a perspective view of the example mask of  FIG. 2  secured to the gear of  FIG. 1 . 
         FIG. 7  shows a perspective view of another example mask in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts. 
     Aspects of the present disclosure relate to a mask that protects the edges of the gear teeth of a gear during a particle impacting process, such as a shot peen or other similar process (e.g., sand or glass bead blasting), without preventing the particle impacting process from effectuating advantageous hardening and other results for areas that are not protected by the mask. The cover may be removable and reusable. Among other advantages, application of the mask may prevent a bulge condition on the tooth tips or edges that may otherwise result from the particle impacting process. Among yet other advantages, by protecting the gear tooth tips, a post shot peen process used in the related art for removing resulting bulges may be eliminated. 
     An example gear, for which a mask in accordance with aspects of the present invention may be used, is shown in  FIG. 1 . As shown in  FIG. 1 , the gear  100  includes a shaft portion  105  having a first end  105   a  and a second end  105   b , and a gear head portion  110  having a first end  110   a  and a second end  110   b . The shaft portion  105  is attached at its second end  105   b  to the first end portion  110   a  of the gear head portion  110 . The gear  100  further includes a recess  115  or other feature usable for temporarily securing a mask to the gear  100 . The gear head portion  110  further includes a plurality of gear teeth  112 , each of the gear teeth  112  having an edge portion  112   a.    
       FIG. 2  shows a perspective view of an example mask  200  in accordance with aspects of the present disclosure. The mask  200  includes a first circular cross-sectional open end portion  205  (also interchangeably referred to herein as an “open ring portion”) located at a first end  200   a  of the mask  200 , and a second circular cross-sectionally shaped closed end portion  210  (also interchangeably referred to as a “closed ring portion”), located at a second end  200   b  of the mask  200 . A plurality of vanes  215  are each connected at their first and second ends  215   a ,  215   b  to the open ring portion  205  and the closed ring portion  210 , respectively. In one variation, each of the vanes  215  may be approximately the same width (e.g., +/−10%) as the width of each the gear teeth (teeth  112 ,  FIG. 1 ). In another variation, the edges of each of the vanes  215  may be beveled, such that the width of each of the vanes  215  is narrower on the side each vane opposite the side facing the teeth (teeth  112 ,  FIG. 6 ), thereby enabling the impacting particles to more easily pass thereby and to therefore impact the gear surface that is not masked. 
       FIG. 3  shows an end view of the example mask  200  of  FIG. 2 , viewed from the direction of end  200   b  ( FIG. 2 ). 
       FIG. 4  shows an end view of the example mask  200  of  FIG. 2 , viewed from the direction of end  205   a  ( FIG. 2 ). As shown in  FIG. 4 , the interior facing side of closed end portion  210  includes a securing feature  220 , such as an extension sized for being received within recess  115  of the gear  100  of  FIG. 1 . 
       FIG. 5  shows a representative cross-sectional view of the example mask  200  of  FIG. 2 , including a cross-sectional view of the securing feature  220 , such as an extension sized for being received within recess  115  of the gear  100  of  FIG. 1  (e.g., by a slight interference fit). 
       FIG. 6  shows a perspective view of the example mask  200  of  FIG. 2  secured to the gear  100  of  FIG. 1 . In  FIG. 6 , the mask  200  is secured via the securing feature on the interior surface of closed end portion  210  to the recess in the head  110  of gear  100 . The mask  200  is positioned such that each of the vanes  215  covers the edge of one of the plurality of gear teeth  112 . 
     In the example implementation of  FIGS. 1-6 , the protective mask  200  may thereby be used, for example, during a particle impacting process, such as a shot peen process, to protect the edges of gear teeth in a gear  100 , in accordance with aspects of the present disclosure. 
     The mask  200  may comprise any suitable material to withstand the particle impacting process and not be unsuitably deformed or worn thereby (e.g., the mask  200  may be of a material allowing reuse a suitable number of times without deformation or wear rendering it unfit for such use). Such material may comprise, for example, steel (e.g., stainless steel), carbon material, or titanium. 
     In the example implementation of  FIGS. 1-6 , the mask  200  has a generally partial conical overall shape so as to match the corresponding generally partial conical overall shape of the gear head  110  of the gear  100  (e.g., a spiral bevel gear). However, the mask may be appropriately shaped for use with gears of other shapes. For example, the mask may have an overall cylindrical shape for being received on a gear head having an overall cylindrical shape (e.g., a non-beveled gear head). 
     Although the mask  200  shown in  FIGS. 1-6  is shown as being secured to the gear  100  via the securing feature  220  received within the recess  115 , the mask  200  may also be secured to the gear  100  via other features (e.g., one or more extensions inwardly extending from the open ring portion  205  so as to be retained beneath the edge of one or more of the gear teeth  112  at end  110   a  ( FIG. 1 ) of the teeth). 
       FIG. 7  shows a perspective view of another example mask  300  in accordance with aspects of the present disclosure that is similar to the mask  200  of  FIG. 2 , but that does not include a ring portion on the open end. The mask  300  of  FIG. 7  includes an open end portion at first end  305   a  of the mask  300 , but the open end portion does not include a ring portion. The mask further includes a circular cross-sectional closed end portion  310 , located at a second end  305   b  of the mask  300 . A plurality of vanes  315  are each connected at one end  315   a  to the closed end portion  310  and extend therefrom. 
     For operation of the particle impacting process on the gear, the gear may be secured (e.g., via the gear shaft), such as within a closeable machine for use in the particle impacting process. The machine may be partially or fully automated in operation. The mask may be attached to the gear via one or more positioning mechanisms and alignment features on the machine for use in manufacturing. For example, the mask may include an alignment mark thereon, and the gear may have a corresponding alignment or feature. The mask may then be aligned relative to the gear and the mask then secured to the gear (e.g., via impacting the mask, such as by a blunt instrument, so as to drive the securing feature on the mask into the recess in the gear head), thereby securing the mask to the gear in the proper position so as to align the mask vanes with the gear teeth edges. 
     The particle impacting process may then be applied, and upon completion, the mask may be removed (e.g., by prying or impacting the mask, such as by a blunt instrument, in a direction to remove it from the gear). The gear may then be removed from the machine or other securing mechanism. 
     While the aspects described herein have been described in conjunction with the example aspects outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that are or may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example aspects, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later-developed alternatives, modifications, variations, improvements, and/or substantial equivalents. 
     Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.” 
     It is understood that the specific order or hierarchy of the processes/flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy in the processes/flowcharts may be rearranged. Further, some features/steps may be combined or omitted. The accompanying method claims present elements of the various features/steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented. 
     Further, the word “example” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “example” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. Nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.