WO1998005937A1 - Method of high speed centrifugal run-out grinding of a pneumatic tire - Google Patents
Method of high speed centrifugal run-out grinding of a pneumatic tire Download PDFInfo
- Publication number
- WO1998005937A1 WO1998005937A1 PCT/US1996/012845 US9612845W WO9805937A1 WO 1998005937 A1 WO1998005937 A1 WO 1998005937A1 US 9612845 W US9612845 W US 9612845W WO 9805937 A1 WO9805937 A1 WO 9805937A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- tire
- tread
- radial run
- radial
- grinder
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/007—Wheeled or endless-tracked vehicles
- G01M17/02—Tyres
- G01M17/022—Tyres the tyre co-operating with rotatable rolls
- G01M17/024—Tyres the tyre co-operating with rotatable rolls combined with tyre surface correcting or marking means
Definitions
- This invention relates to the field of optimizing pneumatic tire uniformity, and more particularly, to a method for correcting radial run-out, and radial force variations by grinding the tread surface of a pneumatic tire with a tire uniformity machine.
- Tire non-uniformities include dimensional variations, such as differences in the dimensions of the belts, beads, liners, and treads of the tires, differences in material properties (e.g. rubber stiffness), and flaws in the cosmetic appearance of the tires. Whatever the type of non-uniformity, they all result from variations n the manufacturing process. For example, dimensional variations may be caused by rubber flow in the tire molds, out-of-round curing bladders or tire molds, off-center loading at press, snaked treads or belts, tilted beads, tilted carcasses relative to belts, and tilted tires in the mold.
- more than one source of variation may compound the extent of a non-uniformity; for example, non-uniform tire stiffness may result from both tire thickness variation and frorr variations in the stiffness property of the rubber itself.
- Two dimensional non-uniformities of special importance are radial run-out and lateral run-out.
- Radial run-out is the variation in the tread radius of a tire, also referred to as tire "out -of - roundness" .
- the primary production variations causing radial run-out are stretched components, wide component splices, grouped component splices, an out-of-round curing bladder, mold or building drum, eccentric carcass relative to belts, snaked chafer, and off-center loading at press.
- Tire non-uniformities may cause one or more of the following effects on tire performance: force variations, imbalance forces and moments, conicity, ply steer and residual self-aligning torque.
- force variations imbalance forces and moments
- conicity conicity
- ply steer residual self-aligning torque.
- the resulting force variations, imbalances, etc. will exceed an acceptable amount and the ride of the vehicle to which such tires are mounted will be adversely affected.
- forces for example, vehicle weight or centrifugal force
- Force variations are fluctuations in the magnitude of the forces which are exerted by a tire to a road surface on which it rolls, thus causing fluctuations in the reaction forces experienced by the vehicle. These variations in the forces are caused by differences in tire stiffness and/or geometry of the tire about its circumference or tread centerline and depend on which increment of the tire tread is contacting the road surface at a particular time. As - an illustration of force variation, a perfectly round tire on a four wheel vehicle may be expected to transmit a constant force of 1/4 of the total weight of the vehicle to the surface, with the corresponding reaction force conveyed to the vehicle, as the vehicle travels. However, if there is a low spot on a tire (i.e.
- Force variations include radial force variation, lateral force variation, and tangential force variation.
- Radial force variation is caused by radial run-out and variations in radial stiffness and is exerted in the radial direction of the tire, or in a direction perpendicular to the axis of rotation and non-tangential to the road surface. Radial force variation causes roughness to the vehicle ride at various speeds. Radial force variation is easily measurable by a variety of standard methods.
- Tangential force variation is a more complex phenomena than the two discussed above. Tangential force variation, or fore-aft force variation, is experienced at the surface of contact between tire and road surface in a direction both tangential to the tire tread and perpendicular to the tire axis of rotation. Tangential force variations are very speed dependent and are experienced as a "push- pull" effect on a tire, which can be analogized to the sensation of a wheel barrow traveling over a bump in the road, i.e. increased force as the wheel barrow is pushed up the bump and decreased force as the wheel barrow travels down the bump. Investigations have shown that there are multiple mechanisms active in causing tangential force variation.
- tangential force variation are essentially unmeasurable on a typical production low speed tire uniformity machine, as discussed m more detail below, which operates at a speed, such as 60 revolutions per minute (RPM) .
- tangential force variation can only be measured at highway speed or above, using a high speed laboratory tire uniformity machine, such as a Model HSU- 1064, available from the Akron Standard Co. of Akron Ohio.
- the tangential force variation parameter can only be measured by sample methods. Still, tangential force variation does represent a tire uniformity characteristic for which 100% testing and correction would be preferred, if available.
- tires are placed first in a production tire uniformity machine to correct force variations and then placed in a tire balancing machine to check for unacceptable imbalance.
- a number of methods have been developed to correct excessive force variations by removal of rubber from the shoulders and/or the central region of the tire tread by means such as grinding. Most of these correction methods include the steps of indexing the tire tread into a series of circumferential increments and obtaining a series of force measurements representative of the force exerted by the tire as these increments contact a surface. This data is then interpreted and rubber is removed from the tire tread in a pattern generated by this interpretation.
- Force variation correction methods are commonly performed with a production tire uniformity machine (TUM) , which includes an assembly for rotating a test tire against the surface of a freely rotating loading wheel.
- TUM production tire uniformity machine
- the tire is rotated at a low speed of about 60 rpm.
- the loading wheel is moved in a manner dependent on the forces exerted by the rotating tire and those forces are measured by appropriately placed measuring devices.
- shoulder and center rib grinders are used to remove a small amount of the tire tread at precisely the location of non- uniformities detected by the measuring devices. As the tire is rotated, it is measured and ground simultaneously.
- a sophisticated, low speed production tire uniformity machine such as a Model No. D70LTX available from the Akron Standard Co.
- Another object of the present invention is to provide a method for simultaneously correcting radial run-out, and radial force variations of a pneumatic tire on a tire uniformity machine.
- Yet another object of the present invention is to grind a tire on a tire uniformity machine to reduce tangential force variation.
- a method for correcting radial run-out, radial and lateral force variations, and static and couple imbalances of pneumatic tires on a tire uniformity machine includes the steps of first rotating a tire, at a high speed on a tire uniformity machine. Then, a center grinder is incrementally advanced towards the center of the tire and material is removed from the circumferential tread of the tire with each incremental advance of the grinder. Simultaneously, radial run-out is measured until the radial run-out at all points about the circumference of the tire are within an acceptable limit of radial run-ou .
- the method of the present invention is expected to reduce tangential force variation due to the effect of grinding the tire while the tire is rotating at a high speed.
- FIG. 1 is a schematic illustration of a force variation machine in accordance with the invention
- Fig. 2 is a side view of a full-faced grindstone, shown adjacent a partial side view of a tire;
- FIGS. 3A and 3B collectively Fig. 3, are detailed views of a radial run-out sensor
- Fig. 4 is a flow diagram outlining the method of the present invention for correcting radial run-out and radial force variations
- Fig. 5 is a flow diagram outlining the radial run-out grinding routine of the present invention.
- Figs. 6A and 6B collectively Fig. 6, are side views of a simplified tread element of a typical pneumatic tire to demonstrate the cantilever behavior of such tread elements, shown before and during contact with a grinding wheel;
- Fig. 7 is a side view of a simplified tread element of a typical pneumatic tire to demonstrate the feathering effect of low speed tire grinding.
- a typical tire uniformity machine (TUM) 10 in accordance with the present invention.
- a tire 12 which is typically a pneumatic tire having a circumferential tire tread 14, with top and bottom shoulder regions and a central region between the top and bottom shoulder regions, and sidewalls 16A,16B.
- the tire 12 can be mounted on a rim 18 secured to a tire spindle 20 and inflated to a desired pressure.
- a center grinder assembly 24 is located adjacent to wheel 12 and has a grinding wheel 26 that is actuated by a motor 28, as shown in
- grinding wheel 26 is a full-faced grinding wheel with a grinding face
- Grinding wheel 26 is moved into and out of engagement with the central region of the tread 14 of tire 12 by a servo positioner (not shown) , such as a conventional hydraulic servo device.
- a current/power transducer 30 is connected to motor
- a shoulder grinder assembly 38 is located approximately 90° clockwise about tire 12 from center grinder assembly 24 and adjacent to the outside diameter of tire 12.
- Shoulder grinder assembly 38 includes substantially identical top and bottom shoulder grinders 40A,40B (only 40A is illustrated and described) which each include a grinding wheel 42A that is actuated by a motor 44A.
- Each grinder 40A,40B is independently moved into and out of engagement with the trea ⁇ shoulder regions of circumferential tread 14 of tire 12. As shown in Fig. 1, top shoulder grinder 40A can be moved into and out of engagement with the top shoulder portions of tread 14 by any conventional means, such as hydraulic servo devices (not shown) .
- Computer 36 conventionally programmed to determine the radial run-out and radial force values of the tire 12 and to control any necessary corrective grinding action, as discussed in U.S. Patent Application Serial No 08/534,809, entitled METHOD OF CORRECTING CONICITY, RADIAL RUN OUT, AND FORCE VARIATIONS IN A PNEUMATIC TIRE, assigned to the assignee of the present invention Goodyear Tire & Rubber Co., and incorporated m its entirety by reference herein.
- Computer 36 is connected to center grinder assembly 24 and shoulder grinder assembly 38 to position and operate the grinding assemblies as required.
- a radial run-out sensor 52 is preferably mounted to center grinder assembly 24 by conventional means (not shown) .
- radial run-out sensor 52 is a commercially available, no-contact probe A no-contact probe is most desirable for the high operating speeds preferred.
- radial run-out sensor 52 would be mounted to tire uniformity machine 10 in a manner that enables sensing face 54 to physically contact a circumferential tread 14 of tire 12 during force variation and run-out correction.
- Radial run-out sensor 52 senses a target area 56, see Fig. 3A, on the center of circumferential tread 14 of tire 12 as the circumferential tread rotates past the fixed position of the radial run-out sensor.
- the operation of the commercial current/power transducer 30, is an important aspect of the present invention.
- grinding wheel 26 is advanced into contact with tire 12 so that there is interference between the tire and grinding wheel. Then, the grinding wheel 26 will remove material from tire 12 up to the depth of the interference. The abrasive action of grinding wheel 26 against tire 12 will be resisted by the tire material being removed until the material being ground off the tire is severed therefrom. This resistance is experienced by the grinding wheel as a moment acting in the direction opposite from the direction of rotation of the grinding wheel 26. The greater the depth of interference between tire 12 and grinding wheel 26, the greater the amount of material which the grinder will remove, and the greater the counter-moment experienced by the grinding wheel and motor 28.
- the amount of grinding work being performed by grinding wheel 26 must be continuously monitored to prevent the occurrence of certain detrimental effects which arise at higher rates of material removal. Excessive grinding causes the sections of tire 12 being ground to heat up rapidly and may cause melting or burning of the tire material. Furthermore, excessive grinding of tire 12 will cause the ground sections of the tire to have a poor cosmetic appearance.
- a control program of computer 36 monitors the amount of grinding work being performed by grinding wheel 26 by the following process.
- the voltage signals generated by current/power transducer 30, which are proportional to the current/power flowing into motor 28, are continuously inputted and stored in computer 36 via electric signal conditioner 34 during the operation of center grinder assembly 24. Computer 36 subtracts a reference value representing the current/power in motor 28 when no grinding is occurring from the inputted signal to derive a grinding work signal .
- the method of the present invention for correcting run-out, and radial force variations of a pneumatic tire using a tire uniformity machine proceeds as follows. After mounting tire 12 on rim 18 of tire uniformity machine 10, the tire is inflated to a specified test pressure. Next, spindle 20 is rotated by motor 22 to bring rim 18 and tire 12 to a designated rotational speed above about 100 rpm and preferably above 200 rpm and most preferably above 350 rpm. Then, radial run-out sensor 52 measures the radial distances R at incremental units of degrees about the circumferential tread 14 for one revolution of tire 12.
- the voltage signals generated by the measurement of the radial distances R are sent to computer 36 via electrical signal conditioner 60 and stored as a radial distance waveform.
- Computer 36 then mathematically operates on the voltage signals from the signal conditioner 60. If computer 36 determines that all values of the radial run-out waveform are at or below an acceptable maximum value of radial run-out, the computer will determine that no corrective grinding is necessary and will initiate action to cease the correction routine. If any value on the radial run-out waveform is above the acceptable maximum value of radial run-out, a control program of computer 36 directs the operations of center grinder assembly 24. In the preferred embodiment of the present invention, the grinding operations, as outlined below, are conducted if the radial run-out is beyond the acceptable maximum amount.
- the grinding routine to correct the radial run-out is conducted using a control program in computer 36 and proceeds as follows. Grinding wheel 26 of center grinder assembly 24 is positioned so that grinding face 27 is located at a first position which is located at a distance from the center of tire 12 slightly greater than the position of maximum radial run-out of the tire as determined by the initial measurement of radial run-out. Then, the servo positioner advances center grinder assembly 24 m equal incremental units of distance toward the center of tire 12 until contact between grinding wheel 26 and circumferential tread 14 of tire 12 is detected by the current/power transducer device 30.
- grinding wheel 26 is advanced in equal incremental units of distance toward the center of tire 12 for as long as radial run-out sensor 52 detects that run-out is present and current/power transducer 30 determines that the amount of grinding work does not exceed the maximum acceptable amount.
- the sections of tread 14 of tire 12 which contact grinding wheel 26 are those sections in which there is radial run-out. As grinding face 27 of grinding wheel 26 contacts the tire 12, material will be removed (i.e. ground) from the tire at these positions having radial run-out.
- computer 36 will cause center grinder assembly 24 to be returned to an initial position on tire machine 10.
- Individual tread elements 80 can be analogized to cantilevers, and as a grinding wheel comes into contact with a tread element, the force of contact caused by the tangential component of the centrifugal force of the rotating grinding wheel causes the cantilever-like tread element to bend, as diagramed in Figs. 6A and 6B .
- the bending of the tread elements during grinding causes "feathering" to result to the tread elements 82 of the tire after grinding has been completed, as illustrated in Fig. 7. That is, one side of the tread element 82 has a higher height H 2 than the other side Hj , i.e.
- each tread element has considerable stiffness, so that the force of contact with a grinding wheel will cause only minimal bending of the cantilever- like element and thus minimal or no feathering results to a tire ground when rotating at a high speed.
- feathering of the tread may be one cause of tangential force variation, tangential force variation should also be reduced.
- a finer grained grinding wheel can be used to remove the same amount of rubber as compared to a rougher grinding wheel grinding a tire rotating at low speeds. The finer grained wheel provides a better grind finish which improves the cosmetic appearance of the tire.
- the routine for correcting the radial run-out and radial force variation of pneumatic tires on a tire uniformity machine includes the steps of first rotating a tire, which is at a state of standard test pressure, to a high speed, then incrementally advancing a center grinder assembly toward the center of the tire and removing material from the circumferential tread of the tire with each incremental advance while measuring radial run-out until the radial run-out at all points about the circumference of the tire are within an acceptable limit of radial run-out.
- the methods of the present invention are expected to reduce tangential force variation due to the effect of grinding the tire while the tire is rotating at a high speed.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Tyre Moulding (AREA)
- Testing Of Balance (AREA)
- Tires In General (AREA)
Abstract
Description
Claims
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU68960/96A AU6896096A (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
PCT/US1996/012845 WO1998005937A1 (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
BR9612689A BR9612689A (en) | 1996-08-02 | 1996-08-02 | High speed centrifugal eccentricity grinding process for a tire |
US09/180,058 US6086452A (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
GB9902202A GB2333731B (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
ZA9706489A ZA976489B (en) | 1996-08-02 | 1997-07-22 | Method of high speed centrifugal run-out grinding of a pneumatic tire. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1996/012845 WO1998005937A1 (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998005937A1 true WO1998005937A1 (en) | 1998-02-12 |
Family
ID=22255564
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1996/012845 WO1998005937A1 (en) | 1996-08-02 | 1996-08-02 | Method of high speed centrifugal run-out grinding of a pneumatic tire |
Country Status (5)
Country | Link |
---|---|
AU (1) | AU6896096A (en) |
BR (1) | BR9612689A (en) |
GB (1) | GB2333731B (en) |
WO (1) | WO1998005937A1 (en) |
ZA (1) | ZA976489B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6651716B1 (en) | 2000-02-23 | 2003-11-25 | The Goodyear Tire & Rubber Company | Method and tire adapted for post cure tire uniformity correction |
US6673184B1 (en) | 2000-02-23 | 2004-01-06 | The Goodyear Tire & Rubber Company | Tire and method for correcting tire uniformity thereof |
US6740280B1 (en) | 2000-04-10 | 2004-05-25 | The Goodyear Tire & Rubber Company | Tire construction method for improving tire uniformity |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998016810A1 (en) * | 1996-10-15 | 1998-04-23 | The Goodyear Tire & Rubber Company | Method of correcting the imbalance of a pneumatic tire with a tire uniformity machine |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3574973A (en) * | 1968-07-02 | 1971-04-13 | Information Dev Corp | Tire uniformity correction machine |
EP0130759A2 (en) * | 1983-07-01 | 1985-01-09 | The Uniroyal Goodrich Tire Company | Tire uniformity grinder |
EP0342773A2 (en) * | 1988-05-16 | 1989-11-23 | General Tire Inc. | Method and apparatus for correcting and buffing tires |
-
1996
- 1996-08-02 AU AU68960/96A patent/AU6896096A/en not_active Abandoned
- 1996-08-02 GB GB9902202A patent/GB2333731B/en not_active Expired - Fee Related
- 1996-08-02 WO PCT/US1996/012845 patent/WO1998005937A1/en active Application Filing
- 1996-08-02 BR BR9612689A patent/BR9612689A/en not_active Application Discontinuation
-
1997
- 1997-07-22 ZA ZA9706489A patent/ZA976489B/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3574973A (en) * | 1968-07-02 | 1971-04-13 | Information Dev Corp | Tire uniformity correction machine |
EP0130759A2 (en) * | 1983-07-01 | 1985-01-09 | The Uniroyal Goodrich Tire Company | Tire uniformity grinder |
EP0342773A2 (en) * | 1988-05-16 | 1989-11-23 | General Tire Inc. | Method and apparatus for correcting and buffing tires |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6651716B1 (en) | 2000-02-23 | 2003-11-25 | The Goodyear Tire & Rubber Company | Method and tire adapted for post cure tire uniformity correction |
US6673184B1 (en) | 2000-02-23 | 2004-01-06 | The Goodyear Tire & Rubber Company | Tire and method for correcting tire uniformity thereof |
US6740280B1 (en) | 2000-04-10 | 2004-05-25 | The Goodyear Tire & Rubber Company | Tire construction method for improving tire uniformity |
Also Published As
Publication number | Publication date |
---|---|
ZA976489B (en) | 1998-02-19 |
BR9612689A (en) | 1999-08-24 |
GB2333731A (en) | 1999-08-04 |
AU6896096A (en) | 1998-02-25 |
GB2333731B (en) | 2001-03-07 |
GB9902202D0 (en) | 1999-03-24 |
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