JURS, Craig (200 Barbours Lane, Greenville, South Carolina, 29607, US)
VANEMBURG, David (104 Winter Brook Lane, Simpsonville, South Carolina, 29681, US)
ZHU, Fang (4 Creedmoor Drive, Greer, South Carolina, 29650, US)
SOCIETE DE TECHNOLOGIE MICHELIN (23 rue Breschet, F- Clermont-Ferrand, Clermont-Ferrand, FR)
CARPENTER, David (126 Country Lane, Piedmont, South Carolina, 29673, US)
JURS, Craig (200 Barbours Lane, Greenville, South Carolina, 29607, US)
VANEMBURG, David (104 Winter Brook Lane, Simpsonville, South Carolina, 29681, US)
ZHU, Fang (4 Creedmoor Drive, Greer, South Carolina, 29650, US)
| WHAT IS CLAIMED IS: 1. An apparatus for testing the resistance to sidewall damage of a tire mounted on a vehicle, comprising: a guide defining a longitudinal travel path and configured for maintaining vehicle movement along the travel path; a wedge-shaped element selectively positionable along a lateral direction towards or away from the tire, the lateral direction being perpendicular to the longitudinal travel path, said wedge-shaped element also selectively positionable along a vertical direction; and a sensing device for determining movement of the vehicle along the lateral direction relative to the apparatus as the vehicle moves along the longitudinal travel path. 2. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 1, wherein the guide comprises a pair of rails mounted upon a ground surface, the rails having a width configured for receiving two tires mounted on one side of the vehicle so as to constrain the movement of the vehicle to the longitudinal travel path. 3. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 1 , wherein the sensing device further comprises a laser mounted upon the apparatus. 4. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 1, wherein the sensing device further comprises a reflector mounted upon the vehicle and configured for reflecting light from the laser. 5. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 4, wherein the sensing device further comprises a recorder for storing information regarding the position of the vehicle as the vehicle moves along the longitudinal travel path. 6. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 1 , further comprising a locking device for selectively fixing the position of the wedge-shaped element along the lateral direction. 7. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 6, further comprising a locking device for selectively fixing the position of the wedge-shaped element along the vertical direction. 8. An apparatus for testing the resistance to sidewall damage of a vehicle- mounted tire as in claim 1, further comprising a camera for recording images of the tire contacting the wedge-shaped element as the vehicle moves along the longitudinal travel path. 9. A method for testing the resistance of tire to sidewall damage, the tire being mounted on a vehicle, the method comprising the steps of: moving the vehicle along a predetermined travel path; rolling the tire into contact with a damage tool during said moving step, the damage tool being selectively positionable along a lateral direction that is substantially perpendicular to the travel path, the damage tool also being selectively positionable along a vertical direction whereby the height of the damage tool relative to the tire may be adjusted; and determining the movement of the vehicle along the lateral direction during said steps of moving and rolling. 10. A method for testing the resistance of tire to sidewall damage as in claim 9, the method further comprising the steps of: advancing the damage tool along the lateral direction and towards the predetermined travel path; and repeating said steps of moving, rolling, and determining. 11. A method for testing the resistance of tire to sidewall damage as in claim 10, further comprising the steps of reiterating said advancing and repeating steps until either the tire is ruptured or until the tire slides off the damage tool. 12. A method for testing the resistance of tire to sidewall damage as in claim 1 1 , further comprising the step of increasing the height of the damage tool if the tire slides off or rolls over the damage tool without puncture during said step of rolling. 13. A method for testing the resistance of tire to sidewall damage as in claim 9, the method further comprising the steps of: increasing the height of the damage tool; and repeating said steps of moving, rolling, and determining. 14. A method for testing the resistance of tire to sidewall damage as in claim 9, wherein said determining step further comprises measuring the distance between the tire and a fixed point along the lateral direction. 15. A method for testing the resistance of tire to sidewall damage as in claim 9, wherein said determining step further comprises directing a laser along the lateral direction and towards the vehicle during said step of moving. 16. A method for testing the resistance of tire to sidewall damage as in claim 9, wherein said vehicle is operated in reverse during said step of moving. 17. A method for testing the resistance of tire to sidewall damage as in claim 9, further comprising the step of applying grease along the longitudinal travel path of the vehicle. 18. A method for testing the resistance of tire to sidewall damage as in claim 9, further comprising the steps of: rupturing the tire during said step of moving; and recording information about the location of the damage tool relative to the tire during said step of rupturing. 19. A method for testing the resistance of tire to sidewall damage as in claim 9, further comprising the step of adjusting information about the location of the damage tool using information about the lateral movement of the vehicle from said determining step. 20. A method for testing the resistance of tire to sidewall damage as in claim 18, further comprising the step of comparing the information from said recording step with similar information for a different tire. 21. A method for testing the resistance of tire to sidewall damage as in claim 9, further comprising the step of lubricating the predetermined travel path. |
RESISTANCE TO SIDEWALL AGGRESSION
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and method for on vehicle testing of the ability of a tire to resist sidewall aggression and therefore damage to the sidewall.
BACKGROUND OF THE INVENTION
[0002] While a tire tread is designed to be in contact with the ground surface and is therefore constructed from compositions intended for this purpose, the sidewalls are generally not designed to be ground contacting. Instead, the sidewalls of a tire typically include a layer of rubber material that covers certain structural elements, such as e.g., the cords of a tire carcass, which extend between and through the sidewalls of the tire. This rubber material is conventionally created from a composition not designed for ground contact but rather for flexibility so that the sidewalls can withstand the repeated flexing of the tire that occurs as it rotates through the contact patch. In addition, this sidewall rubber is typically not as thick as the tread rubber. As such, the sidewalls generally have less resistance than the tread to puncture damage that can occur when the tire is contacted with another object in or along the ground surface.
[0003] Certain tires are intended for more rugged applications where encounters with objects that may puncture or otherwise damage the sidewall can be frequent. For example, for recreational and emergency off-road applications, tires may be subjected to contact with rocks, trees, and other objects that can puncture and deflate a pneumatic tire. Of course, for such tires it is generally desirable to increase their capability to resist sidewall aggression - i.e., to increase their resistance to puncture, rupture, or other sidewall damaging events caused by contact during tire use. Features can be added at, for example, the shoulder region of the tire to help resist certain sidewall aggressions. More particularly, lugs or blocks can be added about the shoulder to protect the sidewall from shoulder aggression by remaining between a dangerous object and the sidewall as the tire rolls over the object.
[0004] While testing tires under actual conditions such as off road environments can provide important information about a tire's ability to resist sidewall aggression, the repeatability of such testing in harsh conditions so that different tires may be accurately compared is very difficult. Even operating the same vehicle over the same path of rocky terrain does not ensure that the tires will be subjected to the same sidewall aggression events on each pass. Rocks and other debris can be moved or affected by each pass of the vehicle 5 thereby ensuring that different conditions will be presented even if the vehicle can be operated along the same path for each pass. A rock that does not present a sharp point during one pass may be repositioned in a manner that becomes more of a sidewall damage threat for the next pass or vice versa. As such, it can be difficult to compare different tires with such testing.
[0005] Accordingly, an apparatus and method for testing a tire's ability to resist damage from sidewall aggression is desirable. More particularly, an apparatus and method that allows for different tires to be evaluated for resistance to sidewall aggression under conditions that can be repeated among multiple tests would be very useful. In addition, such an apparatus or method that can be applied while the tire is mounted on a vehicle of choice would also be very useful. These and other useful aspects of the present invention will be apparent from the description that follows.
SUMMARY OF THE INVENTION
[0006] Objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
[0007] In one exemplary embodiment of the present invention, an apparatus is provided for testing the resistance to sidewall damage of a tire mounted on a vehicle. The apparatus can include a guide defining a longitudinal travel path and configured for maintaining vehicle movement along the travel path; a wedge-shaped element selectively positionable along a lateral direction towards or away from the tire, the lateral direction being perpendicular to the longitudinal travel path, the wedge-shaped element also being selectively positionable along a vertical direction; and a sensing device for determining movement of the vehicle along the lateral direction relative to the apparatus as the vehicle moves along the longitudinal travel path.
[0008] The apparatus may also include a pair of rails mounted upon a ground surface, the rails having a width configured for receiving two tires mounted on one side of the vehicle so as to constrain the movement of the vehicle to the longitudinal travel path. The sensing device may be constructed from a laser mounted upon the apparatus and further include a reflector mounted upon the vehicle and configured for reflecting light from the laser. The sensing device may also include a recorder for storing information regarding the position of the vehicle as the vehicle moves along the longitudinal travel path.
[0009] The apparatus may also include a locking device for selectively fixing the position of the wedge-shaped element along the lateral direction. A locking device may also be included for selectively fixing the position of the wedge-shaped element along the vertical direction. A camera can be provided for recording images of the tire contacting the wedge- shaped element as the vehicle moves along the longitudinal travel path.
[0010] In another exemplary aspect, the present invention provides a method for testing the resistance of a tire to sidewall damage while the tire is mounted on a vehicle. This exemplary method can include the steps of moving the vehicle along a predetermined travel path; rolling the tire into contact with a damage tool during the moving step, the damage tool being selectively positionable along a lateral direction that is substantially perpendicular to the travel path, the damage tool also being selectively positionable along a vertical direction whereby the height of the damage tool relative to the tire may be adjusted; and determining the movement of the vehicle along the lateral direction during the steps of moving and rolling.
[0011] The method can also include advancing the damage tool along the lateral direction and towards the predetermined travel path, and then repeating the steps of moving, rolling, and detenmning. The process of advancing the damage tool laterally and then repeating the steps of moving, rolling, and determining can be repeated until the tire is damaged (e.g., ruptured) or until the tire slides off the damage tool. If the tire begins to ride over or slide off the damage tool without damage (e.g., rupture), then the height of the damage tool can be increased and the process of advancing the damage tool laterally can be repeated.
[0012] Upon damaging the tire, information about the location of the damage tool relative to the tire can be recorded. Information about the location of the damage tool can be adjusted or calibrated using the results of the step of determining the lateral movement of the vehicle. The information about the location of the damage tool at tire rupture can also be compared with similar information from other tires in order to evaluate the relative ability of the tires to resist sidewall aggression.
[0013] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention,
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
[0015] FIG. 1 illustrates an elevation view of an exemplary embodiment of an apparatus that ma be used to test the resistance of a tire to sidewall aggression while the tire is mounted on the vehicle.
[0016] FIG. 2 illustrates a top view of the exemplary embodiment of FIG. 1.
[0017] FIG. 3 illustrates a top view of a vehicle placed into the tire guide of the apparatus of FIG. 1 and in a ready position for testing.
[0018] FIG. 4 illustrates a tire as it drives over an exemplary embodiment of a damage tool.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention relates a tire's resistance to sidewall aggression - i.e. the ability of a tire to avoid puncture, rupture, cutting, or other damage to the sidewall when contacting an object in the roadway. More particularly, the present invention provides an apparatus and method by which a tire may be tested and evaluated for resistance to sidewall aggression. The present invention provides for repeatability of test conditions between various tests and may also be used to provide quantitative data from such testing that can be used, for example, to compare the performance of different tires and/or further develop existing tire designs. For purposes of describing the invention, reference now will be made in detail to embodiments and methods of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features and steps illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
[0020] FIGS. 1 and 2 provide elevation and top views of a test vehicle 100 onto which a tire 105 has been mounted for testing with an exemplary apparatus 120 of the present invention. Apparatus 120 allows tire 105 to be tested on the actual vehicle application intended for a particular tire. In this way, test conditions that may be unique to a particular vehicle, such as e.g., the vehicle weight and suspension, can be applied and replicated during the tests. While many types of tires may be tested using the present invention, tire 105 could be considered as an "off road" tire that is equipped with various features 110 that can help tire 105 resist damage to its sidewall 115 (FIG. 4) when contacting an object in the travel path.
[0021] As best seen in FIGS. 2 and 3, apparatus 120 includes a guide 160 constructed from a pair of rails 170 and 175. Guide 160 defines a longitudinal travel path for vehicle 100. As will be further described below, in order to provide consistency between tests, guide 160 operates to maintain the movement of vehicle 100 along the direction of arrow A as tire 105 is rolled into contact with a damage tool 125 on each test. Rails 170 and 175 maintain the orientation of the tires along one side of vehicle 100 opposite from the side having test tire 105. Depending upon e.g., the width of vehicle 100's tires and the distance between rails 170 and 175, the tires may rub or catch on rails 170 and 175 and thereby induce unwanted lateral (defined as perpendicular to the longitudinal travel path defined by guide 160) movement. Accordingly, rails 170 and 175 can be lubricated to help prevent or minimize such an effect. Rails 170 and 175 are provided by way of example only. Guide 160 may be constructed from other features such as raised concrete, a recess in the road or contact surface, and others.
[0022] On the opposite side from rails 170 and 175, apparatus 120 includes a tray 165 that receives two tires from vehicle 100 including test tire 105. Tray 165 serves to position tire 105 at the proper height for contact with damage tool 125. Tray 165 may also be constructed in a variety configurations including raised concrete, wood, and others.
[0023] As indicated, apparatus 120 also includes a damage tool 125 that appears in the figures as a wedge-shaped device. Damage tool 125 is intended to replicate sidewall aggression - i.e. contact with features that could puncture, rupture, or otherwise damage the sidewall of tire 105. The present invention is not limited to the particular shape illustrated in the figures and other shapes may be used with apparatus 120. Regardless, the consistent application of the same shape for damage tool 125 allows for accurate comparison between tests,
[0024] As indicated by arrow L in FIG. 1, damage tool 125 can be advanced along this lateral direction and into the longitudinal travel path defined by guide 160. More particularly, the lateral position of damage tool 125 relative to the predetermined path for tire 105 can be selected by moving damage tool 125 within rails 155 using handle 150. A locking device (not shown) can be provided to fix the position of damage tool 125 once a lateral position has been selected. For example, to selectively fix the position of damage tool 125, rails 155 could include mechanical fasteners, a rack and pinion, or other mechanisms that hold tool 125 in place as tire 105 makes contact. Similarly, the height of damage tool 125 relative to tire 105 can also be selected by movement along the direction of arrow W, and a locking device (not shown) can also be provided to fix the height of damage tool 125 once selected.
[0025] Even with guides 160 and lubrication of rails 170 and 175, the lateral position of vehicle 100 within guides 160 may vary as vehicle 100 moves along the longitudinal travel path defined by guides 160. In a manner to be more fully described, damage tool 125 will be incrementally advanced into the longitudinal travel path during testing of tire 105. For purposes of comparing test results between tires, it is desirable to know the position of tool 125 relative to tire 105. More particularly, it is desirable to know the actual amount by which damage tool 125 projects into the path of tire 105 so that different tests can be accurately compared.
[0026] Accordingly, referring specifically to FIG. 1, apparatus 120 includes a sensing device 130 that detennines the lateral movement of vehicle 100 as it moves along the longitudinal travel path. For example, in one exemplary embodiment, sensing device 130 includes a laser that is reflected off the vehicle by placing a reflector on the wheel hub. As vehicle 100 passes by, light is reflected and changes in the reflecting intensity can be used to determine whether vehicle 100 has shifted laterally i.e. towards or away from sensor 130. Position sensor 140 provides information about the location of damage tool 125. Therefore, by calibrating position sensor 140 and sensing device 130 and using the information provided by sensor 130 to adjust for lateral movement, the actual amount by which damage tool 125 is projected into the path of tire 105 can be determined even though vehicle 100 may drift along the lateral direction as it moves along the longitudinal travel path provided by guide 160. This positional information (i.e, depth) for damage tool 125 allows for a more accurate comparison of results between various tests despite variations in the lateral movement of vehicle 100 during testing.
[0027] For example, in order to set up apparatus 120 for testing, tire 105 is positioned immediately adjacent to damage tool 125, Damage tool 125 is then positioned laterally and vertically to a position where the tip 180 (FIG, 1) of tool 125 makes contact with the widest part of tire 105 such as e.g., the equator along the sidewall 115. This position is defined as the "zero" for tool 125 and all incremental movements of tool 125 along lateral direction L are measured with reference to this starting point. While tire 105 is in this same position, sensor 130 also provides a reading that is defined as the zero point for the lateral position of tire 105.
[0028] Accordingly, during testing, vehicle 100 will pass sensor 130. Any lateral movement detected by sensor 130 will be used in to determine the "true" amount by which tool 125 is projecting into the path of tire 110. If during a given test run, for example, damage tool 125 has been laterally advanced by 5 mm from its "zero" position, but sensor 130 records lateral movement of tire 105 towards the sensor of 2 mm, then the actual projection of tool 125 into the tire path is only 3 mm. This adjusting for the lateral movement of vehicle 100 is performed constantly as vehicle 100 is moved down the longitudinal travel path defined by guide 160.
[0029] An exemplary method for use with apparatus 120 will now be described beginning with FIG. 3. A vehicle 100 of choice is placed onto apparatus 120 with a selected test tire 105 mounted on the vehicle and positioned upon tray 165. Wheels on the opposite side of vehicle 100 from test tire 105 are placed into guide 160 and, more specifically, between rails 170 and 175.
[0030] After calibration and zeroing of damage tool 125 and sensor 130 as previously described, damage tool 125 is placed at is lowest height. Knowing the "zero" of damage tool 125 as previously described, tool 125 is now advanced laterally along the direction of arrow L into the longitudinal travel path by a chosen incremental amount, and the lateral and vertical position of tool 125 is then fixed or locked in preparation for contact with tire 105 as vehicle 100 passes by. The lateral position and height of damage tool 125 is recorded.
[0031] Vehicle 100 is then backed in the direction of arrow A along the longitudinal travel path defined by guide 160. As tire 105 passes sensor 130, display 135 indicates the amount by and which damage tool 125 extends into the path of tire 105. For example, display 135 may indicate that damage tool 125 extends 5 mm into the path of tire 105. In the event vehicle 100 drifts laterally, sensor 130 determines the amount of this drift and an adjustment is automatically made so that display 135 provides the actual amount by which tool 125 projects into the path of tire 105 at any given point during the test.
[0032] In the event tire 105 is not ruptured or punctured from contact with damage tool 125 during a given pass, vehicle 100 is then returned to its original position (as shown in FIG. 3). Damage tool 125 is now advanced by a predetermined amount along the lateral direction of arrow L so as to increase the amount by which damage tool 125 projects into the path of tire 105. This position is recorded and vehicle 100 is again backed along the direction of the longitudinal travel path so that tire 105 is again rolled into contact with damage tool 125 and then past damage tool 125. As tire 105 passes, sensor 130 again determines whether there is any movement of vehicle 100 along the lateral direction so that the actual amount of projection of damage tool 125 into the path of tire 105 may be indicated from display 135.
[0033] If the sidewall of tire 105 is not damages by damage tool 125, the process of advancing damage tool 125 laterally by an incremental amount and backing vehicle 100 along guide 160 is repeated. "Damage" to the sidewall as used herein includes cutting, puncturing, rupturing, or otherwise damaging the sidewall of the tire. For example, the test can be operated until only one or a combination of these events occurs, whichever event(s) is selected for the test.
[0034] During each pass of tire 105 and lateral advancement of damage tool 125, the wedge-shaped element of tool 125 will project further and further into the path of tire 105. Each time tire 105 rolls into contact with tool 125, there is an opportunity for tool 125 to damage sidewall 115 of tire 105. If sidewall 115 is damaged, then the test is terminated and the lateral position and vertical position (height) of damage tool 125 at the time of such damage (e.g., a puncture) is recorded for tire 105. Alternatively, if tire 105 is not damaged as damage tool 125 is increasingly advanced laterally for each pass of vehicle 100, then tire 105 will eventually begin to either roll over damage tool 125 or slide off tool 125 without damaging sidewall 115. For example, FIG. 4 shows the deformation of tire 105 as it rolls over damage tool 125 without damage, such as e.g., a puncture, to sidewall 115. Once this condition is reached, damage tool 125 is retracted laterally back to its original zero position and the height of damage tool 125 is increased by an incremental amount. Now, the entire process of advancing damage tool 125 along lateral direction L by incremental amounts for a given height are repeated until tire 105 is either damaged or begins rolling over or sliding off damage tool 125, at which point the vertical height of tool 125 is increased and the lateral advancement process is repeated. Camera system 145 (FIGS.l and 2), preferably a high speed system, can be used to record any puncture of tire 105 and provide information for later study. Information provided by display 135 can also be recorded electronically for later use if desired.
[0035] Eventually, for each tire that is tested, a lateral and vertical position will be reached at which a given tire will experience damage to its sidewall 115. By repeating this test for different tires, apparatus 120 provides a valuable and repeatable test by which the resistance of different tires to sidewall aggression may be evaluated. For example, some tires may not be able to resist sidewall puncture even when damage tool 125 is set at a relatively low height and minimal projection into the tire path along lateral direction L. Conversely, other designs may be able to stand deeper projections into the tire path and at greater heights. Both tire architecture and tread design may be evaluated and developed through comparison testing. Accordingly, apparatus 120 provides a repeatable, reliable method of comparing tires of different design and manufacture for resistance to sidewall aggression.
[0036] While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. For example, an exemplary method of the present invention has been described in which the vehicle was driven in reverse over a damage tool. However, the test could be performed driving the vehicle in a forward gear as well. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.