Partial laser PEEN coverage for CAM lobes

Abstract

A cam lobe for a camshaft wherein the cam lobe includes a cam lobe body having a base circle portion with a base circle outer perimeter adjacent a nose portion with a nose outer perimeter. The cam lobe body has a width that spans across an outer perimeter surface of the cam lobe body. The outer perimeter surface includes a laser peened portion and a non-laser peened portion. The laser peened portion can have various configurations and amount of surface densities. The laser peened portion includes a gradual transition of a laser peened surface. The laser peened portion includes a fade or taper on ends or sides towards a lobe centerline such that a width or a length of the laser peened portion is narrowed or eliminated at the lobe centerline.

Description

PARTIAL LASER PEEN COVERAGE FOR CAM LOBESCross-Reference to Related Application:

[0001] The present application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 647,753 filed on May 15, 2024, which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present application relates generally to a cam lobe, and more particularly to a portion of an outer surface of the cam lobe that is treated with laser peening.BACKGROUND

[0003] Camshafts for internal combustion engines typically include several cam lobes with lobe-shaped outer surfaces that operate to move push rods, lifters, or other movable members. As the camshaft rotates, the cam lobes must engage the movable members at proper positions and with proper timing. Due to the engagement or contact with the movable members, contact stress on an outer surface of the cam lobe can happen. Additionally, rolling contact fatigue can happen to the cam lobe. The rolling contact fatigue of the cam lobe is one factor that can determine a life expectancy of the camshaft or the maximum amount of time that the cam lobe can safely operate before failure is expected. Heavy duty engines are very expensive and customers expect these engines to last for a very long time and some engine types are expected to last for over a million miles.

[0004] One technique to reduce the development of rolling contact fatigue is to manufacture the camshaft and cam lobes from a block of bar-stock steel because this type of steel is metallurgical pure. However bar-stock steel is very expensive. To manufacture the camshaft, much of the bar-stock steel is removed from the block of bar-stock steel wherein the removed portion of steel is then wasted. Less expensive and lower quality materials could be used to manufacture the camshaft but these materials are not desirable because the lower quality materials often contain microscopic metallurgical defects or have an unknown composition of material. If metallurgical defects are present in the lower quality materials then these defects can be an origin for rolling contact fatigue to occur in the cam lobe.

[0005] Therefore, further contributions in this area of technology are needed to improve the durability of cam lobes for a camshaft of an engine in a cost effective manner.SUMMARY

[0006] A cam lobe for a camshaft wherein the cam lobe includes a cam lobe body having a base circle portion with a base circle outer perimeter adjacent a nose portion with a nose outer perimeter. The cam lobe body has a width that spans across an outer perimeter surface of the cam lobe body. The outer perimeter surface includes a laser peened portion and a non-laser peened portion. The laser peened portion can have various configurations and amount of surface densities. The laser peened portion includes a gradual transition of a laser peened surface to the non-laser peened surface(s). The laser peened portion includes a fade or taper on ends or sides towards a lobe centerline such that a width or a length of the laser peened portion is narrowed or eliminated at the lobe centerline. Some examples of the laser peened portions include a centerline stripe or a centerline stripe that is narrowed on the base circle outer perimeter. Other examples of the laser peened portions include a taper away completely for the base circle outer perimeter, a fade pattern wherein the surface density is decreased only slightly in the base circle outer perimeter, and a fade away completely pattern wherein the surface density is not increased in the base circle outer perimeter such that no laser peening is performed. The base circle is less susceptible to surface fatigue than the peak of the cam. Therefore, the surface density (of laser peen) should decrease for the base circle. The laser-peen feature will increase for the peak, and decrease for the base circle. The non-laser peened portion includes any area on the outer perimeter surface that is not laser peened.

[0007] This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The concepts described herein are illustrative by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. Where considered appropriate, references labels have been repeated among the figures to indicate corresponding or analogous elements.

[0009] FIG. l is a partial perspective view of a camshaft having one or more cam lobes of the present disclosure.

[0010] FIG. 2 is a side view of one of the cam lobes of FIG. 1.

[0011] FIG. 3 is an illustrative representation of a first embodiment of an outer surface of one of the cam lobes of FIG. 1 that is processed with laser-peening.

[0012] FIG. 4 is an illustrative representation of a second embodiment of an outer surface of one of the cam lobes of FIG. 1 that is processed with laser-peening.

[0013] FIG. 5 is an illustrative representation of a third embodiment of an outer surface of one of the cam lobes of FIG. 1 that is processed with laser-peening.

[0014] FIG. 6 is an illustrative representation of a fourth embodiment of an outer surface of one of the cam lobes of FIG. 1 that is processed with laser-peening.

[0015] FIG. 7 is an illustrative representation of a fifth embodiment of an outer surface of one of the cam lobes of FIG. 1 that is processed with laser-peening.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0016] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein as would normally occur to one skilled in the art to which the invention relates are contemplated herein.

[0017] Turning now to the present application with reference to FIG. 1 is a partial perspective view of a camshaft 20 having one or more cam lobes 22a-22c assembled on a shaft 24. Each of the cam lobes 22a-22c may be the same or different from each other. Cam lobes 22a-22c are exemplary and other configurations, sizes, and shapes are within the scope of this application. The camshaft 20 can be cast material and / or steel material.

[0018] The cam lobe 22b will be described with reference to FIG. 2. The cam lobe 22b includes a cam lobe body 30b that includes a base circle portion 32b adjacent a nose portion 34b. The cam lobe body 30b has an outer perimeter surface 35b that spans across a width 37b of the cam lobe body 30b and between a first face 39b opposite a second face (not illustrated). When the cam lobe body 30b is assembled with the shaft 24, the width 37b spans laterally relative to a centerline of the shaft 24. The outer perimeter surface 35b spans around an outer perimeter of the cam lobe 22b and is limited by the width 37b.

[0019] The cam lobe body 30b includes a first face 39b opposite a second face (not illustrated) wherein the first and second faces are the same or identical. The cam lobe body 30b includes a lobe centerline 36b that runs along a longitudinal length of the cam lobe body 30b.

[0020] During operation of the camshaft 20, the cam lobe 22b will contact a movable member such as a roller. Often an outer perimeter surface of the roller is not cylindrical but instead has a simple or complex crown surface that rolls against the outer perimeter surface 35b of cam lobe 22b. The complex crown surface of the roller can be a barrel shape that includes a slightly bigger diameter at a center and a smaller diameter at the ends of the crown surface. As one example, the complex crown surface can be a spline with many points that have been optimized to minimize the contact fatigue of the outer perimeter surface 35b of the cam lobe 22b that contacts the roller. In this embodiment, since the diameter of the center of the roller isbigger than the ends of the roller, the contact stress is concentrated in a middle portion of the width 37b of the outer perimeter surface 35b. Moreover, the roller contacts the nose portion 34b and in particular a higher amount of force is applied to a cam lobe peak 40b of the nose portion 34b than the base circle portion 32b. As such, the stress imparted is higher at the cam lobe peak 40b as compared to the base circle portion 32b which has a much lower stress applied to it. A lesser amount of force is applied by the roller to an opening ramp 42b and a closing ramp 44b of the nose portion 34b as compared to the cam lobe peak 40b.

[0021] The base circle portion 32b has a circular shape with a center 41b that corresponds to the lobe centerline 36b. The base circle portion 32b includes a heel 38b that spans along a portion of the outer perimeter surface 35b of the base circle portion 32b. In FIG. 1, a heel 38a is illustrated wherein heel 38a is similar to heel 38b. In one embodiment, the heel 38b spans approximately 180 degrees as measured relative to the center 41b of the base circle portion 32b and along the outer perimeter surface 35b. The base circle portion 32b includes a base circle outer perimeter 3 lb that spans between an opening ramp 42b and a closing ramp 44b of the nose portion 34b. The base circle outer perimeter 3 lb includes the heel 38b. The base circle portion 32b has a base circle width 39b that corresponds to a diameter of the base circle portion 32b.

[0022] The nose portion 34b includes a cam lobe peak 40b that spans between an opening ramp 42b and a closing ramp 44b and along the outer perimeter surface 35b. The cam lobe peak 40b includes the lobe centerline 36b positioned in the middle of the cam lobe peak 40b. The opening ramp 42b includes a curved or straight surface for a corresponding portion of the outer perimeter surface 35b. The closing ramp 44b can include a curved or straight surface for a corresponding portion of the outer perimeter surface 35b. The nose portion 34b defines a lift 50b that is measured from a diameter of the base circle portion 32b along the lobe centerline 36b. The lift 50b corresponds to a maximum distance that the cam lobe 22b can move the movable members. The nose portion 34b includes a nose outer perimeter 43b that includes the opening ramp 42b, the cam lobe peak 40b, and the closing ramp 44b.

[0023] There is a long cycle time associated with laser peening an entire outer surface of a cam lobe that is cast or made of steel. Since the stress applied by the roller or other movable member is highest at limited areas or regions on the outer perimeter surface 35b of the cam lobe 22b then these corresponding regions are treated to increase the density of the outer perimetersurface 35b. The densification may be accomplished by, for example, by shot peening or laser peening.

[0024] In one embodiment, the laser peening is performed with two or three laserpeening machines having two lasers each and may partially cover the cam lobe 22b. In one embodiment, partial coverage of the cam lobe 22b was approximately 30% of the outer surface area and in particular the outer perimeter surface 35b. In another embodiment, partial coverage of the cam lobe 22b was approximately 15-50% of the outer surface area and in particular the outer perimeter surface 35b. The cam lobe 22b that has been laser peened allows use of less expensive cast camshaft rather than machining the camshaft from steel bar stock material.

[0025] In order to reduce the cycle time for laser peening, only the highly stressed areas of the cam lobe 22b are laser peened. It is further determined that an abrupt transition between laser peened and un-processed areas (not treated with laser peening) of the outer perimeter surface 35b is detrimental as an abrupt transition or discontinuity would reduce a rolling contact fatigue life of the cam lobe 22b. Moreover, an abrupt transition is difficult for manufacturing the cam lobe 22b. The sudden change would result in an out-of-specification surface finish of the outer perimeter surface 35b at the transition. A discontinuity is a location on the outer perimeter surface 35b where the laser peening treated areas start and stop abruptly.

[0026] Turning now to FIG. 3 is an illustrative representation of the outer perimeter surface 35b wherein a laser peened portion 60b spans across a middle portion of the width 37b of the outer perimeter surface 35b. The laser peened portion 60b includes a centerline, CL, of the width 37b and portions of the width 37b on either side of the centerline, CL. In other embodiments, the laser peened portion 60b may be shifted closer to either of the first and second faces. In yet other embodiments, the laser peened portion 60b includes a laser peened base portion 62b that corresponds to the base circle outer perimeter 3 lb. The laser peened base portion 62b may include a gradual transition for laser peening the outer perimeter surface 35b wherein the laser peened base portion 62b is not as heavily treated with the lasers from the laserpeening machines. In this embodiment, the laser peened portion 60b includes a laser peened nose portion 64b that corresponds to the nose outer perimeter 43b wherein the laser peened nose portion 64b has an increased or higher density of laser peening than the laser peened base portion 62b. The outer perimeter surface 35b includes a non-laser peened portion 66b that is any area on the outer perimeter surface 35b that is not laser peened.

[0027] Turning now to FIG. 4 is an illustrative representation of the outer perimeter surface 35b wherein a laser peened portion 70b spans across a middle portion of the width 37b of the outer perimeter surface 35b. The laser peened portion 70b includes the centerline, CL, of the width 37b and portions of the width 37b on either side of the centerline, CL. In other embodiments, the laser peened portion 70b may be shifted closer to either of the first and second faces. The laser peened portion 70b includes a laser peened base portion 72b that corresponds to the base circle outer perimeter 3 lb. The laser peened base portion 72b tapers on both ends towards the lobe centerline 36b such that a width of the laser peened base portion 72b is narrowed at the lobe centerline 36b which results in less of a surface area of the outer perimeter surface 35b being treated with laser peening in the laser peened base portion 72b. In this embodiment, the laser peened portion 70b includes a laser peened nose portion 74b that corresponds to the nose outer perimeter 43b wherein the laser peened nose portion 74b has an increased or higher density of laser peening than the laser peened base portion 72b. The outer perimeter surface 35b includes a non-laser peened portion 76b that is any area on the outer perimeter surface 35b that is not laser peened.

[0028] Turning now to FIG. 5 is an illustrative representation of the outer perimeter surface 35b wherein a laser peened portion 80b spans across the width 37b of the outer perimeter surface 35b. The laser peened portion 80b includes a laser peened base portion 82b that corresponds to the base circle outer perimeter 3 lb. The laser peened base portion 82b includes tapered portions 83b on both ends. The tapered portions 83b taper across the width 37b towards the lobe centerline 36b such that a non-laser peened portion 86b of the laser peened base portion 82b is not treated with any laser peening at the lobe centerline 36b which results in less of a surface area of the outer perimeter surface 35b being treated with laser peening in the laser peened base portion 82b. The non-laser peened portion 86b is not laser peen treated. The laser peened portion 80b includes a laser peened nose portion 84b that corresponds to the nose outer perimeter 43b wherein the laser peened nose portion 84b has an increased or higher density of laser peening than the laser peened base portion 82b.

[0029] Turning now to FIG. 6 is an illustrative representation of the outer perimeter surface 35b wherein a laser peened portion 90b spans across the width 37b of the outer perimeter surface 35b. The laser peened portion 90b includes a laser peened base portion 92b that corresponds to the base circle outer perimeter 3 lb. The laser peened base portion 92b fades orreduces the amount of laser peening towards the lobe centerline 36b which results in less of a surface area of the outer perimeter surface 35b being treated with laser peening in the laser peened base portion 92b. The amount of laser peening on the laser peened base portion 92b is represented schematically. The laser peened portion 90b includes a laser peened nose portion 94b that corresponds to the nose outer perimeter 43b wherein the laser peened nose portion 94b has an increased or higher density of laser peening than the laser peened base portion 92b. The amount of laser peening on the laser peened nose portion 94b is represented schematically.

[0030] Turning now to FIG. 7 is an illustrative representation of the outer perimeter surface 35b wherein a laser peened portion 100b spans across the width 37b of the outer perimeter surface 35b. The laser peened portion 100b includes a laser peened base portion 102b that corresponds to the base circle outer perimeter 3 lb. The laser peened base portion 102b may not be treated with laser peening in the laser peened base portion 102b. The laser peened portion 100b includes a laser peened nose portion 104b that corresponds to the nose outer perimeter 43b wherein the laser peened nose portion 104b has an increased or higher density of laser peening than the laser peened base portion 102b. The laser peened nose portion 104b fades or reduces the amount of laser peening towards the laser peened base portion 102b. The amount of laser peening on the laser peened nose portion 104b is represented schematically.

[0031] All of the embodiments disclosed herein can include a gradual transition for laser peening the outer perimeter surface 35b wherein any of the laser peened base portions 62b, 72b, 82b, 92b, and / or 102b are not as heavily treated with the lasers from the laser-peening machines as compared to the laser peened nose portion 64b, 74b, 84b, 94b, and / or 104b. The transition from non-laser peened surface to laser peened surface can be gradual or tapered. Any of the embodiments disclosed herein can be combined.

[0032] As is evident from the figures and text presented above, a variety of aspects of the present disclosure are contemplated.

[0033] Various aspects of the present application are contemplated. According to one aspect, a cam lobe for a camshaft, the cam lobe comprising: a cam lobe body having a base circle portion adjacent a nose portion, the cam lobe body has an outer perimeter surface that spans about the base circle portion and the nose portion and between a first face and a second face, wherein the outer perimeter surface includes a non-laser peened portion and a laser peenedportion, the laser peened portion has a surface density that is greater than a surface density of the non-laser peened portion.

[0034] In one embodiment, wherein the laser peened portion includes a laser peened base portion and a laser peened nose portion, the laser peened base portion includes a base circle outer perimeter surface of the base circle portion, the laser peened nose portion includes a nose outer perimeter surface of the nose portion.

[0035] In one embodiment, wherein the surface density of the laser peened base portion is less dense than the surface density of the laser peened nose portion.

[0036] In one embodiment, wherein the laser peened base portion includes a tapered portion that tapers from the first and second faces towards a lobe centerline of the cam lobe body.

[0037] In one embodiment, wherein the non-laser peened portion includes a portion of the base circle outer perimeter surface that is adjacent to the tapered portion of the laser peened base portion.

[0038] In one embodiment, wherein the laser peened portion spans across a middle portion of a transverse width of the outer perimeter surface that extends between the first face and the second face.

[0039] In one embodiment, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp.

[0040] In one embodiment, wherein the laser peened portion includes a laser peened nose portion that includes a nose outer perimeter surface of the nose portion.

[0041] In one embodiment, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp, wherein the laser peened nose portion has a higher surface density at the cam lobe peak and a lower surface density at either of the opening or closing ramps.

[0042] In one embodiment, wherein the non-laser peened portion includes the base circle outer perimeter surface of the base circle portion.

[0043] In one embodiment, wherein the laser peened base portion is aligned with a lobe centerline of the cam lobe body.

[0044] In one embodiment, wherein the laser peened base portion is closer to the first face than to a lobe centerline of the cam lobe body.

[0045] According to another aspect, a cam lobe for a camshaft, the cam lobe comprising: a cam lobe body having a base circle portion adjacent a nose portion, the cam lobe body has an outer perimeter surface that spans about the base circle portion and the nose portion and between a first face and a second face, wherein the outer perimeter surface of the base circle portion includes a laser peened base portion and the outer perimeter surface of the nose portion includes a laser peened nose portion, wherein a surface density of the laser peened base portion is less dense than a surface density of the laser peened nose portion.

[0046] In one embodiment, wherein the laser peened base portion includes a tapered portion that tapers from the first and second faces towards a lobe centerline of the cam lobe body.

[0047] In one embodiment, wherein the laser peened base portion and / or the laser peened nose portion is aligned with a lobe centerline of the cam lobe body.

[0048] In one embodiment, wherein the laser peened base portion and / or the laser peened nose portion is closer to the first face than to a lobe centerline of the cam lobe body.

[0049] In one embodiment, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp, wherein the laser peened nose portion has a higher surface density at the cam lobe peak and a lower surface density at either of the opening or closing ramps.

[0050] In one embodiment, wherein the outer perimeter surface of the base circle portion includes a non-laser peened base portion that has a lower surface density than the surface density of the laser peened base portion.

[0051] In one embodiment, wherein the outer perimeter surface of the nose portion includes a non-laser peened nose portion that has a lower surface density than the surface density of the laser peened nose portion.

[0052] In one embodiment, wherein the laser peened base portion and / or the laser peened nose portion spans across a middle portion of a transverse width of the outer perimeter surface that extends between the first face and the second face.

[0053] In the above description, certain relative terms may be used such as “up,” “down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” “proximal,” “distal,” and the like.These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions,and / or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same object.

[0054] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. Similarly, the use of the term “implementation” means an implementation having a particular feature, structure, or characteristic described in connection with one or more embodiments of the present disclosure, however, absent an express correlation to indicate otherwise, an implementation may be associated with one or more embodiments.

[0055] The described features, structures, advantages, and / or characteristics of the subject matter of the present disclosure may be combined in any suitable manner in one or more embodiments and / or implementations. In the following description, numerous specific details are provided to impart a thorough understanding of embodiments of the subject matter of the present disclosure. One skilled in the relevant art will recognize that the subject matter of the present disclosure may be practiced without one or more of the specific features, details, components, materials, and / or methods of a particular embodiment or implementation. In some instances, the benefit of simplicity may provide operational and economic benefits and exclusion of certain elements described herein is contemplated as within the scope of the invention herein by the inventors to achieve such benefits. In other instances, additional features and advantages may be recognized in certain embodiments and / or implementations that may not be present in all embodiments or implementations. Further, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the subject matter of the present disclosure. The features and advantages of the subject matter of the present disclosure will become more fully apparent from the following description and appended claims, or may be learned by the practice of the subject matter as set forth hereinafter.

[0056] The present subject matter may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

What is claimed is:

1. A cam lobe for a camshaft, the cam lobe comprising: a cam lobe body having a base circle portion adjacent a nose portion, the cam lobe body has an outer perimeter surface that spans about the base circle portion and the nose portion and between a first face and a second face, wherein the outer perimeter surface includes a non-laser peened portion and a laser peened portion, the laser peened portion has a surface density that is greater than a surface density of the non-laser peened portion.

2. The cam lobe of claim 1, wherein the laser peened portion includes a laser peened base portion and a laser peened nose portion, the laser peened base portion includes a base circle outer perimeter surface of the base circle portion, the laser peened nose portion includes a nose outer perimeter surface of the nose portion.

3. The cam lobe of claim 2, wherein the surface density of the laser peened base portion is less dense than the surface density of the laser peened nose portion.

4. The cam lobe of claim 2, wherein the laser peened base portion includes a tapered portion that tapers from the first and second faces towards a lobe centerline of the cam lobe body.

5. The cam lobe of claim 4, wherein the non-laser peened portion includes a portion of the base circle outer perimeter surface that is adjacent to the tapered portion of the laser peened base portion.

6. The cam lobe of claim 1, wherein the laser peened portion spans across a middle portion of a transverse width of the outer perimeter surface that extends between the first face and the second face.

7. The cam lobe of claim 1, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp.

8. The cam lobe of claim 1, wherein the laser peened portion includes a laser peened nose portion that includes a nose outer perimeter surface of the nose portion.

9. The cam lobe of claim 8, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp, wherein the laser peened nose portion has a higher surface density at the cam lobe peak and a lower surface density at either of the opening or closing ramps.

10. The cam lobe of claim 8, wherein the non-laser peened portion includes the base circle outer perimeter surface of the base circle portion.

11. The cam lobe of claim 1, wherein the laser peened base portion is aligned with a lobe centerline of the cam lobe body.

12. The cam lobe of claim 1, wherein the laser peened base portion is closer to the first face than to a lobe centerline of the cam lobe body.

13. A cam lobe for a camshaft, the cam lobe comprising: a cam lobe body having a base circle portion adjacent a nose portion, the cam lobe body has an outer perimeter surface that spans about the base circle portion and the nose portion and between a first face and a second face, wherein the outer perimeter surface of the base circle portion includes a laser peened base portion and the outer perimeter surface of the nose portion includes a laser peened nose portion, wherein a surface density of the laser peened base portion is less dense than a surface density of the laser peened nose portion.

14. The cam lobe of claim 13, wherein the laser peened base portion includes a tapered portion that tapers from the first and second faces towards a lobe centerline of the cam lobe body.

15. The cam lobe of claim 13, wherein the laser peened base portion and / or the laser peened nose portion is aligned with a lobe centerline of the cam lobe body.

16. The cam lobe of claim 13, wherein the laser peened base portion and / or the laser peened nose portion is closer to the first face than to a lobe centerline of the cam lobe body.

17. The cam lobe of claim 13, wherein the nose portion includes a cam lobe peak that spans between an opening ramp and a closing ramp, wherein the laser peened nose portion has a higher surface density at the cam lobe peak and a lower surface density at either of the opening or closing ramps.

18. The cam lobe of claim 13, wherein the outer perimeter surface of the base circle portion includes a non-laser peened base portion that has a lower surface density than the surface density of the laser peened base portion.

19. The cam lobe of claim 18, wherein the outer perimeter surface of the nose portion includes a non-laser peened nose portion that has a lower surface density than the surface density of the laser peened nose portion.

20. The cam lobe of claim 13, wherein the laser peened base portion and / or the laser peened nose portion spans across a middle portion of a transverse width of the outer perimeter surface that extends between the first face and the second face.

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