# Patent

## Title
Super charger components

## Abstract

A pulley assembly having a body, a shaft mount and a plurality of bolts is disclosed. The body is aligned to the shaft mount by providing a tight tolerance between a shoulder portion of the bolt and a neck portion of a counter sunk hole formed in the body. Additionally, an outer surface of the body may have a pattern of friction lines or patches formed by fusing particulate matter to the outer surface with heat generated by a laser beam.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
Not Applicable
BACKGROUND
The various embodiments and aspects described herein relate to components for a supercharger of an automobile.
The supercharger has a pulley which is connected to a rotating shaft of the engine and drives the supercharger. The pulley has a small diameter which leads to slippage between the pulley and the belt driving the pulley.
Accordingly, there is a need in the art for an improved method and device for mitigating slippage between the pulley and the belt and addressing other deficiencies.
BRIEF SUMMARY
The various embodiments and aspects disclosed herein address the needs discussed above, discussed below and those that are known in the art.
A pulley assembly having a body, a shaft mount and a plurality of bolts that attach the body to the shaft mount is disclosed. The shaft mount is mountable to a shaft of a supercharger. The body is attachable to the shaft mount with the bolts. In particular, the shaft mount has a plurality of threaded holes that engage threads of the bolts. The body has a series of counter sunk holes that are aligned to the threaded holes of the shaft mount. The counter sunk holes have a neck area that is minimally larger than a shoulder area of the bolt. As such, when the bolt is inserted into the counter sunk holes and threaded into the threaded holes of the shaft mount, the tight tolerancing (i.e., within 0.001 inches) between diameters of the necks of the counter sunk holes and the shoulder of the bolts align the body of the pulley assembly to the shaft mount and ultimately to the shaft of the supercharger. In another aspect, the outer surface of the body of the pulley assembly has a pattern of friction lines for increasing the frictional forces between the outer surface of the body of the pulley assembly and the belt driving the pulley. The friction lines are formed by applying particulate matter to the outer surface of the body of the pulley assembly and fusing the applied particulate matter to the outer surface by heating the outer surface and the particulate matter. The heat may be generated by a laser beam that traces a desired pattern of friction lines. The increased friction mitigates noise by reducing slippage between a belt and the pulley.
More particularly, a pulley for transmitting rotational motion between first and second rotating shafts with a belt on an automobile engine is disclosed. The pulley may be fixed to the first rotating shaft. The pulley comprising a body and a laser infused friction material. The body may have a cylindrical central hole for receiving the first rotating shaft and mounting the body onto the first rotating shaft on the automobile engine. The cylindrical central hole may define a central axis about which the body rotates. The body may have at least one groove formed circumferentially about the central axis for receiving the belt. The laser infused friction material may be bonded to an outer surface of the at least one groove.
The laser infused friction material may be configured into a pattern on the outer surface of the at least one groove. The pulley may have at least three grooves. The pulley may have a diameter of about 1-10 inches, and more preferably between about 2-4 inches, and even more preferably about 2.5 inches.
In another aspect, a method of fabricating a pulley for transmitting rotational motion between first and second rotating shafts with a belt on an automobile engine is disclosed. The pulley may be fixed to the first rotating shaft. The method may comprise the steps of forming a body having a cylindrical central hole for receiving the first rotating shaft and mounting the body onto the first rotating shaft on the automobile engine, the cylindrical central hole defining a central axis about which the body rotates, the body having at least one groove formed circumferentially about the central axis for receiving the belt; covering an outer surface of the at least one groove with a powder material; and selectively applying heat from a laser beam to the powder material and the outer surface of the at least one groove to fuse the powder material to the outer surface of the at least one groove. The fused powder material provides a surface texture to increase its coefficient of friction and reduce slip with another material such as a belt.
The powder material used in the method may be a formulation sold under the trademark THERMARK or CERMARK. The powder material used in the method may also be any powdered metallic material or powdered oxide material. By way of example and not limitation, the metallic material may be titanium, aluminum, steel or combinations thereof. The average size of the of the powdered material may be up to about 100 microns, and is preferably up to about 35 microns. More preferably, the powdered material is between about 20-25 microns. The texture of the fused material may be increased or decreased by respectively using larger or smaller sized powdered oxide material.
The powder material and the outer surface of the at least one groove may reach a temperature of at least 200 degrees Fahrenheit to fuse the powder material to the outer surface of the groove. Additionally, the powder material may be configured so that the fusing temperature of the powder material and the outer surface may be as high as about 1000 degrees Fahrenheit.
In the method, the covering step may include the step of covering the entire outer surface of the at least one groove.
In the method, the applying step may comprise the steps of mounting the body to a chuck; mounting the body and the chuck to a laser machine; rotating the body with the chuck while performing the applying heat from the laser beam step, rotational motion of the body defining a rotational axis; and traversing a head of the laser machine along the rotational axis while performing the applying heat from the laser beam step.
In another aspect, a method of removing a pulley from a rotating shaft of an automobile engine is disclosed. The method may comprise the steps of unscrewing a plurality of first bolts from the pulley to disassemble a first outer body of the pulley from an inner mounting fixture of the pulley; removing the first outer body from the inner mounting fixture; positioning a second outer body over the inner mounting fixture wherein an internal configuration of the second outer body is sized to interface with the inner mounting fixture and an external configuration of the second outer body is sized to mate with a puller; screwing the plurality of first bolts or a plurality of second bolts to the pulley to fix the second outer body to the inner mounting fixture wherein the second outer body has a larger flange compared to a flange of the first outer body; engaging the puller to the larger flange of the second outer body; and pulling on the larger flange of the second outer body with the puller to remove the inner mounting fixture from the rotating shaft.
In the method, the larger flange of the second outer body may be located on an inner side of the pulley.



BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which:
FIG. 1 is a perspective view of a pulley assembly mounted on a shaft of the supercharger;
FIG. 2 is a cross-sectional exploded view of the pulley assembly shown in FIG. 1;
FIG. 3 is a cross-sectional view of the pulley assembly illustrating a bolt that aligns a body of the pulley assembly to a shaft mount of the pulley assembly;
FIG. 4 is a flowchart for forming friction lines on an outer surface of the body of the pulley assembly;
FIG. 5 illustrates a laser beam used to fuse particulate matter on the outer surface of the body of the pulley assembly for forming the friction lines;
FIG. 6 is a front view of a variable diameter pulley of a continuously variable transmission;
FIG. 7 is a front view of one of first and second parts of the variable diameter pulley individually mounted to a chuck; and
FIG. 8 is a front view of one of first and second parts of the variable diameter pulley individually mounted to a chuck in a different orientation to a laser beam of a laser.



DETAILED DESCRIPTION
Referring now to the drawings, a pulley assembly 10 for a supercharger 12 is shown. The pulley assembly 10 is mounted to a shaft 14 of the supercharger 12. The pulley assembly 10 may have three different components, namely, a shaft mount 16, a body 18 and a plurality of bolts 20. The body 18 is mounted to the shaft mount 16 with the plurality of bolts 20. In particular, each of the bolts 20 may have a shoulder 22 having an outer diameter 24 which is smaller than and within 0.001 inches of an inner diameter 26 of a neck 54 of a countersunk hole 28 formed in the body 18. The shaft mount 16 has a plurality of threaded holes 30 which receive the bolts 20. In this manner, the neck 54 of the body 18 aligns the body 18 to the shaft mount 16. Additionally, an outer surface 32 of the body 18 may have a plurality of friction lines 34 which mitigate slip between the outer surface 32 of the body 18 and a belt being driven by the pulley assembly 10 or driving the pulley assembly 10. The increased friction mitigates noise by reducing slippage between the belt and the pulley assembly 10.
More particularly, referring now to FIG. 2, the pulley assembly 10 is made up of at least the shaft mount 16, the body 18 and the plurality of fasteners or bolts 20. To mount the pulley assembly 10 to the shaft 14 of the supercharger 12, the shaft mount 16 is heated to a temperature above the temperature of the shaft 14. The inner diameter 36 of the hole 38 of the shaft mount 16 is enlarged due to the heat so that the shaft mount 16 may be slid over the shaft 14. When the shaft mount 16 cools down, the shaft mount 16 is fixedly secured to the shaft 14 of the supercharger 12. The inner diameter 36 of the hole 38 of the shaft mount 16 is slightly smaller than an outer diameter 40 of the shaft 14 when the shaft 14 and the shaft mount 16 are at the same temperature. The shaft mount 16 compresses on the shaft 14 when the temperature of the shaft mount 16 reaches the temperature of the shaft 14.
The shaft mount 16 may have a flange 42 that extends outwardly around a periphery of the shaft mount 16. The flange 42 may have a plurality of threaded holes 44 symmetrically disposed about a central axis 46. The flange 42 may have a proximal surface 48 which mates with a distal surface 50 of the body 18. The body 18 is mounted to the shaft mount 16 with the plurality of fasteners 20. The body 18 has a set of corresponding countersunk holes 28 that receive the bolts 20. These countersunk holes 28 are aligned in the same pattern as the threaded holes 44 formed in the flange 42 of the shaft mount 16. The body 18 has an inner cavity 55 which is large enough to receive the shaft mount 16 and a portion 53 of the supercharger 12 that holds the shaft 14. The body 18 is disposed over the shaft mount 16 and the countersunk holes 28 are aligned to the threaded holes 44. Each of the fasteners 20 are then inserted through the countersunk holes 28 and engage to the threaded holes 44 of the shaft mount 16. The fasteners 20 fixedly secure the body 18 the shaft mount 16. Also, the interference fit between the hole 38 of the shaft mount 16 and the shaft 14 of the supercharger 12 fixedly secure the shaft mount 16 to the shaft 14.
To align the body 18 to the shaft mount 16, the bolts 20 have a shoulder 22 that mates to a neck 54 of the countersunk hole 28 formed in the body 18. In particular, referring now to FIG. 3, a cross-sectional view of the pulley assembly 10 is shown. The countersunk hole 28 has two different diameters. A first diameter at a neck 54 identified as inner diameter 26. A second diameter at a countersunk portion 56 identified as inner diameter 58. The inner diameter 58 receives a head 60 of the bolt 20. More particularly, the inner diameter 58 is significantly larger than an outer diameter 62 of the head 60 of the bolt 20. In contrast, the inner diameter 26 of the neck 54 of the threaded hole 28 is only minimally larger than an outer diameter 24 of the neck portion 22 of the bolt 20. More particularly, the inner diameter 26 is within 0.001 inches of the outer diameter 24 of the neck 22 of the bolt 20. As the threads 64 of the bolt 20 engage the threads 66 of the threaded hole 30 of the flange 42 of the shaft mount 16, the shoulder 22 of the bolt 20 enters the neck 54 of the hole 28 of the body 18. Since the inner diameter 26 of the hole 28 is within 0.001 inches to the outer diameter 24 of the shoulder 22, the body 18 begins to align to the shaft mount 60 as two or more bolts 20 engage the threaded holes 44 of the shaft mount 16.
Optionally, to further secure the shaft mount 16 to the shaft 14, the shaft mount 16 may have one or more socket set screws 68 that engage the shaft 14. In particular, the shaft mount 16 may have an extended length. A threaded hole 70 may be formed in the extended length. Preferably, a plurality of threaded holes 70 are symetrically formed about the central axis 46 to maintain rotational balance of the pulley assembly 10 during rotation. By way of example and not limitation, threaded holes 70 may be placed on opposed sides of the central axis 46. Alternatively, three holes 70 may be disposed 120° apart from each other about the central axis 46 or four holes may be disposed 90° apart from each other about the central axis 46. After the shaft mount 16 is mounted to the shaft 14, the socket set screws 68 are threaded into the threaded holes 70 and engaged to the shaft 14. Preferably, the socket set screws 68 have a knurled end to further engage the shaft 14.
To mount the pulley assembly 10 to the shaft 14 of the supercharger 12, the shaft mount 16 (see FIG. 2) is heated to a temperature above the temperature of the shaft 14 of the supercharger 12. In doing this, the heat enlarges the inner diameter 36 of the shaft mount 16 so that the inner diameter 36 of the shaft mount 16 when heated is greater than the outer diameter 40 of the shaft 14. While the shaft mount 16 is heated to an elevated temperature, the shaft mount 16 is placed over the shaft 14 so that the shaft 14 is now disposed within the hole 38 of the shaft mount 16. As the shaft mount 16 cools down, the inner diameter 36 of the shaft mount 16 decreases. When the temperature of the shaft mount 16 is equal to the temperature of the shaft 14, the inner diameter 36 of the shaft mount 16 is equal to the outer diameter 40 of the shaft 14. Since the inner diameter 36 of the shaft mount 16 is less than the outer diameter 40 of the shaft 14 (when the shaft mount 16 and the shaft 14 are at the same temperature and the shaft mount 16 is not mounted to the shaft 14), the inner surface defining the inner diameter 36 of the shaft mount 16 compresses upon the outer surface of the shaft 14 when the shaft mount 16 is mounted to the shaft 14 of the supercharger 12.
To further ensure that the shaft mount 16 is retained on the shaft 14, socket set screws 68 may be threaded into the threaded holes 70 formed in the extended length of shaft mount 16. A distal tip of each of the socket set screws 68 may have knurls to further engage the shaft 14 and mitigate inadvertent movement between the shaft mount 16 and the shaft 14.
The body 18 is then disposed over the shaft mount 16 so that the shaft mount 16 is disposed within the cavity 55 of the body 18. The bolts 20 are inserted through the countersunk holes 28 of the body 18 and threadedly engaged to the threaded holes 44 formed in the flange 42 of the shaft mount 16. As the bolts 20 are tightened, the neck 54 of the bolts 20 seat into the neck 54 of the body 18. Due to the tight tolerances between the shoulders 22 of the bolts 20 and the necks 54 of the countersunk holes 28 of the body 18, the body 18 begins to align to the shaft mount 16. The user tightens the bolts 20 to securely attach the body 18 to the shaft mount 16, and in turn, to the shaft 14 of the supercharger 12.
To remove the pulley assembly 10 from the shaft 14 of the supercharger 12, the user loosens the bolts 20 to remove the body 18 from the shaft mount 16. The purpose of removing the body 18 from the shaft mount 16 is to provide the user with access to the socket set screws 68, if used. The user loosens and removes the socket set screws 68 from the shaft mount 16. The user may then reinstall the original body 18 or install a sacrificial body 72 (see FIG. 2). The sacrificial body 72 may incorporate the counter sunk holes 28 and an enlarged distal flange 74. The enlarged distal flange 74 is used to pull the body 18 and shaft mount 16 off of the shaft 14. The user may then pull the pulley assembly 10 from the shaft 14 with the puller.
Referring back to FIG. 1, the body 18 of the pulley assembly 10 may have an outer surface 32. The outer surface 32 may have a plurality of grooves 76 circumscribing the body 18 about the rotational axis 46. In the embodiment shown in the figures, the pulley assembly 10 has a plurality of grooves. However, it is also contemplated that the various aspects described herein may be applied to a pulley have a single groove or a pulley or tensioner having a cylindrical surface. The outer surface 32, and in this instance, the grooves 76 engage a belt that wraps around the body 18 and fits within the grooves 76. The outer surface 32 of the body 18 may be smooth so that during use, the belt wrapped around the body 18 may inadvertently slip so that the linear speed of the outer surface 32 of the body 18 is not equal to the linear speed of the belt driving or driven by the pulley assembly 10. To mitigate slippage between the belt and the outer surface 32 of the body 18, friction patches or lines 34 may be formed on the outer surface 32 of the body 18.
In particular, referring now to FIGS. 4 and 5, particulate matter or substance may be fused to the outer surface 32 of the body 18 and have a coefficient of friction with the belt greater than the coefficient of friction between the smooth outer surface 32 of the body 18 and the belt. The particulate matter may be coated over the outer surface 32. A laser beam 78 of the laser 80 may be directed to selective locations on the outer surface 32 of the body 18 to fuse the particulate matter to the outer surface 32 of the body 18. Preferably, the particulate matter when fused to the outer surface 32 has a coefficient of friction with the belt greater than the coefficient of friction between the smooth outer surface 32 of the body 18 and the belt. Moreover, the particulate matter provides a slight raised surface so that the edges of the friction lines 38 create additional friction between the friction lines 34 and the belt. The fusing of the particulate matter to the outer surface 32 of the body 18 is a physical bonding process wherein the particulate matter is heated and permanently bonded to the outer surface 32 of the body 18.
To coat the particulate matter onto the outer surface 32 of the body 18, the particulate matter is applied 82 (see FIG. 4) to the outer surface 32 of the body 18. The particulate matter may be applied 82 to the outer surface 32 of the body 18 either by way of an aerosol 100 or airbrushing 102. If the particulate matter is delivered or coated onto the outer surface 32 of the body 18 with an aerosol 100, the aerosol can 100 is purchased in a prepackaged form. The user sprays the entire outer surface 32 of the body 18, and more particularly, sprays the grooves 76. If the particulate matter is delivered or coated onto the outer surface 32 of the body 18 by way of airbrushing 102, the particulate matter is mixed with denatured alcohol then sprayed on the outer surface 32 with a sprayer. Two types of particulate matter may be utilized when air brushing. A first type is one sold under the trademark Thermark. A second type is one sold under the trademark Cernark. For low production runs, the Thermark particulate matter is preferred since un-fused particulate matter on the outer surface 32 is easily removed by wiping with a damp wet rag. However, for large production runs, Cernark is preferred since the particulate matter may be applied to the outer surface 32 of the body 18 and stored for an extended period of time.
If Thermark is used, then the user applies the particulate matter shortly before fusing 82 the particulate matter to the outer surface 32 of the body 18. If Cermark is used, then the user may optionally store 84 the coated bodies 18 in storage for an extended period of time. When desired, the user takes the coated bodies 18 out of storage and fuses 82 the particulate matter to the outer surface 32 of the body 18. Regardless of whether Thermark or Cermark is utilized, the particulate matter may be fused 82 to the outer surface 32 of the body 18 with a laser beam 78. The laser beam 78 heats up the particulate matter and the outer surface 32 of the body 18. The heat permanently attaches the particulate matter to the outer surface 32 of the body 18 so that the particulate matter does not rub off as the belt runs over the outer surface 32 of the body 18.
Generally, the particular matter may be provided as a powder. The powder may be delivered by aerosol or a spray gun. The material of the powder may be a metallic material. More particularly, the powder may be any form of a metallic oxide material. By way of example and not limitation, the metallic material may be titanium, aluminum, steel or combinations thereof. The average size of the of the powdered material may be up to about 100 microns, and is preferably up to about 35 microns. The texture of the fused material may be increased or decreased by respectively using larger or smaller sized powdered oxide material. During tests, a powder metallic oxide material having a size of about 35 microns has created a 0.007 inch texture to the outer surface 32.
To form the friction lines or patches 34, the body 18 may be attached to a chuck 86 after applying the particulate matter to the outer surface 32. The chuck 86 may have a plurality of arms 88 with serrated teeth. The plurality of arms 88 may be inserted within the internal cavity 55 of the body 18 and expanded outward. Upon outward expansion, the arms 88 automatically center the body 18 onto the chuck 86. The chuck 86 and the body 18 are placed on a rotary table or an indexer that controls the rotational movement 90 of the chuck 86 and the body 18 about rotational axis 46. The laser 80 is capable of traversing longitudinally along the central or rotational axis 46 in the direction of arrows 92, 94. Preferably, the laser beam 78 of the laser 80 intersects and is perpendicular to the central or rotational axis 46. Additionally, the laser 80 may be a direct beam laser 80.
The laser beam 78 may be traversed longitudinally along the axis 46 and simultaneously, the body 18 may be rotated about axis 46 so that the laser beam 78 traces the pattern of lines, circles, curves, patches and other shapes to form a mark, word, pattern on the outer surface 32 of the grooves of the body 18. In FIG. 1, the friction lines 34 are shown as being linear along the longitudinal length of the central axis 46. However, other types of patterns and shapes are also contemplated.
After fusing 82, the particulate matter to the outer surface 32 of the body 18, the excess particulate matter which is not fused to the outer surface 32 of the body 18 may be removed 96 and reclaimed 98 for subsequent use. More particularly, the body 18 may be placed in a wash tank such as an ultrasonic tank. Fluid within the ultrasonic tank is heated up to 200° F. and the tank is vibrated. The fluid is run through a filter and the particulate matter that was not fused to the body 18 is reclaimed 98 and reused at a later time.
The direct beam laser 80 produces a laser beam 78 having a focal depth 104. Preferably, the focal depth 104 is greater than a distance 106 between a peek 108 and valley 110 of the grooves 76 formed in the body 18. The laser 80 and laser beam 78 are positioned so that the focal depth 104 covers the entire distance 106. By way of example and not limitation, the focal depth 104 of the laser beam 78 may be about 0.200 inches. In this manner, the laser beam 78 heats up the particulate matter and the surface 32 along the entire height of the grooves 76 to provide optimal friction lines 34.
It is also contemplated that the process of forming the friction lines 34 as discussed above and in relation to FIGS. 4 and 5 may be repeated over existing friction lines 34 as shown by process line 112 (see FIG. 4). In particular, after fusing 82, the particulate matter to the surface 32 of the body 18, additional particulate matter may be applied 82 to the outer surface 32 of the body 18. The additional particulate matter may be fused 82 to the layer of fused particulate matter and to the bare metal of the body 18. The process may be repeated to increase the thickness of the layers of particulate matter on the outer surface 32 of the body 18.
Other types of lasers 80 may also be utilized to fuse 82 the particulate matter to the outer surface 32 of the body 18. By way of example and not limitation, a Galvo laser which utilizes one or more lenses to position the laser beam 78 on the outer surface 32 of the body 18 may be utilized. In this manner, the throughput is higher than a direct laser beam 78 or a CO2 laser beam in that the lenses can create multiple friction lines 34 in one pass.
The process of forming the friction lines 34 is discussed in relation to FIGS. 4 and 5 with the process of producing and emboss on the outer surface 32 of the body 18. However, it is also contemplated that a deboss may be formed on the outer surface 32 of the body 18 by removing material. In particular, the Galvo laser may be utilized to remove material from the outer surface 32 of the body 18. The Galvo laser utilizes one or more lenses to redirect the laser beam 78 instead of moving the laser head 80 to position the laser beam 78 on the outer surface 32 of the body 18.
In addition to forming the deboss on the outer surface 32 with the laser 80, it is also contemplated that the deboss may be formed with a micro end mill. Regardless of whether the deboss is formed with a laser 80 or a micro end mill, the body 18 is mounted to the chuck 86. The chuck 86 and the body 18 are mounted to an indexer or a rotary table which controls the rotational angle of the body 18 as the micro end mill or the laser 80 removes material from the outer surface 32 of the body 18. In another aspect, it is also contemplated that the body 18 may remain stationary while the micro end mill or the laser 80 both rotate about the body 18 and also traverse longitudinally along the axis 46.
The friction lines or patches 34 were described as being formed on a rotary table or indexer that is coordinated with the laser. However, it is also contemplated that the friction lines or patches 34 may be formed manually. By way of example and not limitation, the part could be mounted to a chuck or a holding mechanism that the user may move by hand.
In another aspect, referring now to FIG. 6, the friction lines or patches may be formed on other types of pulleys, and also on tensioning rollers having a cylindrical flat surface. By way of example and not limitation, the friction lines or patches 34 may be formed on inner surfaces 118 of first and second parts 120, 122 of a variable diameter pulley 124 of a continuously variable transmission. When the belt 126 is closer to the rotational axis 128, the revolutions per minute of the pulley 124 is higher than when the belt 126 is further away from the rotational axis 128.
Referring now to FIG. 7, to form the friction lines or patches 34 on the inner surface 118, the first and second parts may each be individually mounted to the chuck 86. The part 120 or 122 is positioned with the inner surface 118 perpendicular to the laser beam 78. The form the patches or lines 34, the laser 80 is traversed laterally in the direction of arrows 92 and 94 and the chuck 86 is rotated in direction of arrow 90 about rotating axis 46.
Referring now to FIG. 8, a different set up between the part 120, 122 and the laser beam 78 is shown. Instead of the part 120, 122 being oriented so that the laser beam 78 is perpendicular to the inner surface 118, the inner surface 118 may be oriented at a skewed angle with respect to the laser beam 78. In FIG. 8, the rotational axis of the part 120, 122 is set up so as to be perpendicular to the laser beam 78. Since the laser beam 78 has a particular focal depth 104 which is the location of the laser beam effective for heating up the particular matter and the inner surface 118 to fuse the two together, the laser 80 cannot simply be laterally traversed in a linear as shown in FIG. 7 if the angle of the inner surface 118 is too large so that the entire surface 118 is within the focal depth 104 of the laser beam. If the laser is moved to the left 94 or right 92, the laser beam 78 is effective at fusing the particulate matter to the inner surface 118 as long as the inner surface 118 is within the focal depth of the laser beam. Right before the inner surface 118 comes out of the focal depth of the laser beam 78, the laser may be traversed up 128 or down 130 to reposition the focal depth of the laser beam on the inner surface 118. To form the friction lines or patches 34, the laser 80 is traversed sideways 92, 94 and vertically 128, 130 in a staggered fashion. This technique can also be used for pulleys that have a deep groove wherein the distance 106 between the peak 108 and the valley 110 of the deep groove is greater than the focal depth 104 of the laser beam 78.
The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including usage of other types of lasers. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.

## Claims

1. A pulley for transmitting rotational motion between first and second rotating shafts with a belt on an automobile engine, the pulley being fixed to the first rotating shaft, the pulley comprising:
a body having a cylindrical central hole for receiving the first rotating shaft and mounting the body onto the first rotating shaft on the automobile engine, the cylindrical central hole defining a central axis about which the body rotates, the body having at least one groove formed circumferentially about the central axis for receiving the belt, a friction material laser infused to less than 100% of the at least one groove, the at least one groove defining a valley and a peak, the body fabricated from a metallic material; and
the friction material laser infused solely to an outer surface of the body and to the at least one groove from the peak to the valley of the at least one groove, the friction material being a powdered metallic material or powdered oxide material.

2. The pulley of claim 1 wherein the friction material is configured into a pattern on the outer surface of the at least one groove.

3. The pulley of claim 1 wherein the pulley has at least three grooves.

4. The pulley of claim 1 wherein a diameter of the pulley is between about 2-4 inches in diameter.

5. The pulley of claim 1 wherein the grooves have a depth greater than 0.200 inches.

6. The pulley of claim 1 wherein the powdered material has an average size of between 20-100 microns.