摘要:
Tires are measured for a parameter correlated to a tendency to contribute to steering pull when used on a vehicle. A group of the measured tires is then ranked into a successive series by ordering the parameter measurements of the tires in the group non-decreasingly or non-increasingly. A set of at least two tires of substantially consecutive rank are then selected for mounting on the same vehicle in order to reduce steering pull.
摘要:
Tires are measured to determine the value of a parameter indicating a tendency of the tires to cause vibration in a given direction in tire/wheel assemblies. Each measured tire is assigned a tire rank designation in accordance with the order in which its measured value of the magnitude of that parameter falls in relation to the magnitudes of that parameter among a certain group of tires. Wheels are measured to determine the value of a second parameter indicating a tendency of the wheels to cause vibration in tire/wheel assemblies in that same given direction. Each wheel in a certain group of wheels is ranked in accordance with the order in which the magnitude of its second parameter falls in relation to the magnitudes of the second parameter among the other wheels in the group. Tires and wheels having corresponding respective rank designations are paired with one another to be combined into a tire/wheel assembly wherein the tire and wheel are mutually oriented such that the vibrational tendencies of the first and second parameters tend to cancel one another.
摘要:
An apparatus and method for predicting fore-aft translations of tires. An inflated tire is rotated at a nominally constant angular velocity against a freely rotatable rigid loadwheel under a radial load. Changes in the instantaneous effective radius of the tire as it rolls give rise to fore/aft forces which tend to translate the tire alternately forward, toward the direction of travel and aft, toward the opposite direction. The tendency of the tire to so translate is predicted by measuring variations in effective radius or a parameter correlated thereto such as changes in the motion of the tread surface of the tire or the loadwheel relative to the angular speed of the tire.
摘要:
A tire uniformity inspection machine is calibrated by applying to at least one force measuring channel thereof a signal which simulates the application of a force of a magnitude greater than any force actually applied to the machine during calibration. That signal, which is preferably of a magnitude appropriate to simulate the largest forces encountered during actual tire testing, can be generated by connecting the channel, preferably at its input, to an energy source through an impedance. The response of the channel to the signal is measured and a calibration factor is determined based on that response. Such calibration factor accounts for the actual behavior of the channel more truely than prior art calibration techniques which relied solely upon the relatively small signal excitation conditions achievable by applying a relatively small actual force to the machine. Thus, the invention affords tire uniformity measurements of improved accuracy.
摘要:
The mass of a tire/wheel assembly is altered to apply a static imbalance to the assembly in a manner which reduces the overall tendency of the assembly to cause vibration in the plane perpendicular to its axis of rotation when in use. The applied imbalance, combined with any static imbalance initially inherent in the tire/wheel assembly, results in a desired net static imbalance oriented so as to induce a centrifugal force which opposes, and therefore tends to cancel, at least one component, such as the first order harmonic, of radial force variation characterizing the assembly. The magnitude of the net static imbalance is limited and is preferably selected to substantially equal the lesser of either: (a) a predetermined maximum limit, or (b) the amount of static imbalance required to generate at a designated highway speed a centrifugal force whose magnitude substantially equals that of the aforementioned radial force variation component.
摘要:
Apparatus and methods for use in measuring the uniformity of a body such as a tire, wheel or the like wherein a waveform related to the uniformity of the body is digitally sampled to acquire a series of data samples, each of which is correlated with a respective physical location on the body. According to a first aspect of the invention, a non-repetitive error component of the waveform is corrected for by sampling the same location on the body at two different times and determining the difference between the corresponding data samples. A part of the total difference is allocated to each of the data samples in the series according to a predetermined methematical function which at least approximately describes the non-repetitive component of the waveform. The part of the difference allocated to each sample is then subtracted from it to obtain a corrected series of data sample. According to a second aspect of the invention, the maximum, minimum and/or peak-to-peak values of the waveform are more accurately determined by relating selected extreme data samples and one or more data samples adjacent thereto to a polynomial function of at least second order. The function is then evaluated at the location where its first derivative equals zero to determine a more accurate and repeatable approximation of a maximum, minimum or peak-to-peak value of the waveform. According to yet another aspect of the present invention the first and second aspects above are practiced in conjunction with one another.
摘要:
Apparatus for inflating tires to a test pressure. The apparatus includes a shop supply of air and a regulated supply of air. A valve system is used to connect the tire to the shop supply to seat the bead on the test rim; to exhaust the air from the tire to bring the pressure in the tire to approximately the test pressure; and to the regulated supply to bring the air in the tire to the preselected test level. The difference between the actual test pressure and the desired test pressure is measured and that difference is used to control the pressure regulator so as to correct the test pressure in the next succeeding tire.
摘要:
Method of inflating tires wherein the tires are inflated to a bead seat pressure and thereafter the pressure is reduced without deflating the tires through the valve.
摘要:
A tire testing machine having a rotatably but actuatably fixed upper rim, a rotatable lower rim assembly and a hydraulic cylinder for raising and lowering the lower rim to a desired position. The lower rim assembly has a resiliently-biased center pilot in the form of a cone that is engageable with a recess in the upper rim to center the lower rim with respect to the upper rim and to transmit rotational forces from the upper rim to the lower rim. The centering action of the pilot is assisted by a pair of mating spherical washers associated with the lower rim assembly.
摘要:
An arrangement for measuring the rolling resistance of tires. The arrangement includes a horizontal roadwheel and several horizontally rotatable tires which are urged against the roadwheel and rotated thereby. The tire spindle assembly is borne by a carriage which is movable toward and away from the roadwheel on a floating platform. The radial force with which the tire is urged against the roadwheel is offset by a linkage structure attached between the platform and the fixed base of the roadwheel assembly such that instantaneous rotation of the platform relative to the roadwheel base is about the axis of rotation of the roadwheel. The linkage structure includes a load cell for measuring the radial force. The arrangement further includes a load cell generally at the perimeter of the roadwheel which measures the tangential rolling resistance force of the tire.