JP2011145098A - Method of measuring residual cornering force of tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of measuring residual cornering force of a tire, capable of performing high-accuracy measurement in a very short time, and also efficient measurement in a relatively small space. <P>SOLUTION: The tire W mounted rotatably on a tire support shaft 3 is maintained while being brought into pressure contact with the top of a flat-plate-shaped movable table 2 with a prescribed load, and the movable table 2 is moved in the direction intersecting perpendicularly the direction of rolling of the tire W while the tire W keeps on rolling on the movable table 2. Self-aligning torque and cornering force are measured from the tire W rolling on the movable table 2, and based on the results of the measurement, the residual cornering force is calculated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for measuring a residual cornering force which is one of the characteristics of a tire attached to a vehicle.

  One of the characteristics of tires attached to vehicles such as automobiles is residual cornering force. Residual cornering force is related to the straight running stability of the vehicle when the tire is attached to the vehicle, but there are individual differences even between the same type of tires. It is effective to grasp the remaining cornering force of tires.

  Conventionally, for example, a tire is pressed against a peripheral surface of a rotating drum, and a cornering force when a self-aligning torque generated by the rotation of the tire at this time becomes zero is measured as a residual cornering force (Patent Document). 1).

  The self-aligning torque is a moment generated around an axis passing through the center of the tire perpendicular to the road surface when a slip angle is given to the rolling tire. The cornering force is a force generated in an axial direction passing through the center of the tire perpendicular to the traveling direction of the rolling tire.

  According to the conventional method, first, when a self-aligning torque is generated in the tire rotating on the peripheral surface of the rotating drum, a slip angle is given to the tire by the self-aligning torque. Thereafter, the tire is balanced with the slip angle when the self-aligning torque becomes zero and is in a stable state. At this time, the cornering force accompanying the slip angle is measured as the residual cornering force.

JP-A-6-294709

  However, according to the above-described conventional method, it takes a relatively long time until the rotation of the tire at the slip angle at which the self-aligning torque becomes zero after the tire that has received the rotation of the drum starts rotating. The measurement efficiency of residual cornering force is poor.

  Further, according to the conventional method, since the tire rotates while being pressed against the circumferential surface of the curved drum, it is difficult to accurately reproduce the state of the tire in contact with the flat road surface. Therefore, in order to bring the peripheral surface of the drum closer to a flat road surface, it is necessary to increase the outer diameter of the drum, but this disadvantageously increases the size of the device and requires a large space.

  In view of the above points, an object of the present invention is to provide a method for measuring a residual cornering force of a tire that can perform measurement in a relatively small space as well as perform highly accurate measurement in a very short time. And

  A first aspect of the method for measuring a residual cornering force of a tire according to the present invention includes an attachment step of rotatably attaching a tire to a tire support shaft, and the tire support shaft to which the tire is attached by the attachment step. A load applying step of pressing the tire on a flat movable table by applying a predetermined load to the tire; and maintaining the pressure contact state of the tire against the movable table by the load applying step. A tire rolling step for rolling a predetermined distance at a speed, and a table moving step for moving the movable table in a direction perpendicular to the rolling direction of the tire when the tire is rolling by the tire rolling step. , Self-aligning torque and corner of the tire from the tire rolling on the movable table moved by the table moving step A measuring step of measuring the ring force, characterized in that it comprises a calculation step of calculating a residual cornering force based on the measurement result by the measuring step.

  In the first aspect of the present invention, first, a tire is supported on a tire support shaft by the attaching step, and the tire is pressed onto a movable table by the load applying step. In the load application step, a load is applied to the tire via the tire support shaft, and the load at this time is preferably equal to the load applied to the tire when the tire is attached to the vehicle and grounded. .

  Next, the tire is rolled on the movable table by the tire rolling step. At this time, the tire moving speed is set to a predetermined constant speed. Furthermore, the movable table is moved by the table moving step while the tire is rolling. In the table moving process, since the movable table is moved in a direction orthogonal to the rolling direction of the tire, a state equivalent to that in which a slip angle is given to the rolling tire is obtained. As a result, a self-aligning torque and a cornering force corresponding to the applied slip angle are generated in the tire. Then, the self-aligning torque and the cornering force at this time are measured by the measuring step, and the residual cornering force is calculated by the calculating step using the measured self-aligning torque and the cornering force.

  As described above, according to the present invention, it is equivalent to giving a slip angle to a tire simply by moving the movable table while rolling the tire on the movable table by the tire rolling step and the table moving step. Since the condition can be created, the self-aligning torque and the cornering force can be generated in the tire in a very short time, the measurement step and the calculation step can be performed quickly, and the residual cornering force can be measured efficiently. Can do.

  Furthermore, since the tire rolls on a flat movable table, it is possible to reliably reproduce the state of the tire in contact with the flat road surface as compared with the case where the tire is pressed against the peripheral surface of the drum that rotates the tire as in the past. And the residual cornering force can be accurately measured.

  By the way, the relationship between the self-aligning torque Mz that changes according to the slip angle and the cornering force Fy can be expressed by a linear function equation (Fy = aMz + b). Therefore, if the change rate a is obtained in advance, the intercept b can be easily calculated as the remaining cornering force only by measuring the self-aligning torque Mz and the cornering force Fy corresponding to a single slip angle. . If the rate of change a is not obtained, the intercept b can be easily calculated as the remaining cornering force by measuring the self-aligning torque Mz and the cornering force Fy corresponding to two different slip angles. it can.

  And when the rate of change a is not obtained, in the present invention, in the table moving step, the moving speed of the movable table is changed when the tire is rolling by the tire rolling step, In the measuring step, a self-aligning torque and a cornering force that change with a change in the moving speed of the movable table are measured. In this way, the remaining cornering force can be obtained relatively easily and accurately in the calculation step. That is, when the moving speed of the movable table is changed in the table moving step, the tires rolling on the movable table are in the same state as when different slip angles are given before and after the speed change of the movable table. . As a result, two different coordinates corresponding to the respective slip angles can be obtained, and the residual cornering force can be obtained very easily using the linear function equation.

  A second aspect of the method for measuring a residual cornering force of a tire according to the present invention includes an attachment step of rotatably attaching a tire to a tire support shaft, and the tire support shaft to which the tire is attached by the attachment step. A load applying step of pressing the tire onto a flat table by applying a predetermined load to the tire, and maintaining the pressure contact state of the tire against the table by the load applying step. A tire rolling step for rolling a predetermined distance at a speed, a slip angle applying step for applying a slip angle to the tire rolling on the table by the tire rolling step, and a slip applied by the slip angle applying step Self-aligning torque and cornering force of the tire are measured from the tire rolling on the table with a corner. A measurement step of, characterized in that it comprises a calculation step of calculating a residual cornering force based on the measurement result by the measuring step.

  According to the second aspect of the present invention, first, the tire is supported on the tire support shaft by the attaching step, and the tire is pressed on the table by the load applying step. The table only needs to have a flat upper surface. In the load application step, a load is applied to the tire via the tire support shaft. The load at this time is preferably the same as the load applied to the tire when the tire is attached to the vehicle and grounded, as in the first aspect.

  Next, the tire is rolled on the table by the tire rolling step. At this time, the tire moving speed is set to a predetermined constant speed. Furthermore, a predetermined slip angle is imparted to the tire by the slip angle imparting step.

  As a result, the tire rolls on the table with a predetermined slip angle. Then, a self-aligning torque and a cornering force corresponding to the applied slip angle are generated in the tire. Then, the self-aligning torque and the cornering force at this time are measured by the measuring step, and the residual cornering force is calculated by the calculating step using the measured self-aligning torque and the cornering force.

  As described above, according to the present invention, it is only necessary to roll a tire provided with a slip angle on a flat table by the tire rolling step and the slip angle applying step for a predetermined distance. A self-aligning torque and a cornering force can be generated in the tire, the measurement step and the calculation step can be performed quickly, and the residual cornering force can be measured efficiently.

  Furthermore, since the tire rolls on a flat table, it is possible to reliably reproduce the state of the tire in contact with the flat road surface as compared with the case where the tire is pressed against the peripheral surface of the rotating drum as in the prior art. The residual cornering force can be accurately measured. In addition, the said calculation process in the 2nd aspect of this invention is the same as the 1st aspect of this invention mentioned above. That is, when the change rate a is obtained in advance based on the relationship between the self-aligning torque Mz and the cornering force Fy expressed by the linear function formula (Fy = aMz + b), it corresponds to a single slip angle. The self-aligning torque Mz and the cornering force Fy are measured, and the intercept b is calculated as the residual cornering force. When the change rate a is not obtained, the slip angle applied to the tire is changed by two different slip angle applying steps, and the self-aligning torque Mz and the cornering force Fy corresponding to each slip angle are changed. Can be easily calculated as the residual cornering force.

  And when change rate a is not obtained, in the 2nd mode of the present invention, in the slip angle grant process, the slip given to a tire when the tire is rolling by the tire rolling process The angle is changed, and the self-aligning torque and the cornering force that change with the change of the slip angle are measured in the measurement step. By doing so, two different coordinates corresponding to the respective slip angles can be obtained only by rolling the tire over a predetermined distance, and the residual cornering force can be obtained very easily using the above linear function formula. Therefore, not only can the measurement process be performed in a very short time, but also the residual cornering force can be determined relatively easily and accurately in the calculation process.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory perspective view which shows schematic structure of the apparatus used in the 1st Embodiment of this invention. Explanatory drawing of the force and moment of each direction which act on a tire. Explanatory drawing which shows the motion of the tire and movable table in a measurement process. Explanatory drawing which shows typically the behavior of the tire with respect to a movable table. The graph which shows the relationship between a self-aligning torque and a cornering force. Other graphs showing the relationship between self-aligning torque and cornering force. Explanatory drawing which shows the measurement process in the 2nd Embodiment of this invention. Explanatory drawing which shows typically the behavior of the tire which moves on a table.

  First, a first embodiment of the present invention will be described. FIG. 1 shows a measuring apparatus 1 for carrying out the measuring method of the first embodiment. The measuring device 1 includes a flat movable table 2, a tire support shaft 3 that rotatably supports a tire W, a lift frame 4 that lifts and lowers the tire W via the tire support shaft 3, and a lift frame 4. And a moving frame 5 for moving the tire W.

  The movable table 2 is slidably supported by a plurality of rails 6 and is moved in the horizontal direction along the rails 6 by appropriate driving means such as a motor (not shown).

  The tire support shaft 3 includes a 6-component force sensor 7 and is provided on the lifting frame 4.

  The lifting frame 4 is lifted and lowered by an appropriate driving means such as a motor (not shown). In the lowered state, a predetermined load is applied to the tire W supported by the tire support shaft 3 so that the tire W is placed on the upper surface of the movable table 2. Press contact.

  The moving frame 5 is slidably supported on a rail 8 that extends horizontally perpendicular to the moving direction of the movable table 2, and is moved along the rail 8 by appropriate driving means such as a motor (not shown).

  Further, the measuring device 1 performs desired measurement based on control data (not shown) for controlling the driving means of the movable table 2, the lifting frame 4, and the moving frame 5, and detection data output from the 6-component force sensor 7. Arithmetic processing means (not shown) comprising a computer for calculating and displaying values.

  As shown in FIG. 2, the 6-component force sensor 7 includes three forces (Fx, Fy, Fz) acting on the tire W in three axial directions and three moments (Mx, My, Mz) around each axis. A sensor that outputs six component forces as detection data is used.

  Next, a method for measuring the residual cornering force of the tire W using the measuring device 1 will be described.

  First, the tire W to be measured is attached to the tire support shaft 3 (attachment process). Subsequently, the elevating frame 4 is lowered, and the tire W is pressed onto the movable table 2 (load application step). At this time, when the tire W is pressed on the movable table 2, a force Fz in the vertical axis direction passing through the center of the tire W perpendicular to the upper surface of the movable table 2 corresponding to the road surface is detected by the six-component force sensor 7. The The said control means controls the drive means of the raising / lowering frame 4 so that the force Fz detected by the 6-component force sensor 7 is maintained constant. The load applied to the tire W is preferably equal to the load applied to the tire W when the tire W is attached to a vehicle (not shown) and grounded. In the present embodiment, the load is set to 4.2 kN. ing. This load is maintained until the end of measurement by the control means controlling the drive means of the lifting frame 4.

  Next, the tire W is rolled on the movable table 2 by moving the moving frame 5 along the rail 8 at a predetermined speed (tire rolling process). In this embodiment, the moving speed of the moving frame 5 at this time is set to 7 km / h. This speed is maintained until the end of measurement by controlling the driving means of the moving frame 5 by the control means. Further, the distance by which the tire W is rolled by the moving frame 5 is set to 1 to 2 rotations (about 5 m) of the tire W. And when the tire W is rolling on the movable table 2 with the movement of the moving frame 5, the movable table 2 is moved in the direction orthogonal to the rolling direction of the tire W (table movement process). As a result, as shown in FIG. 3, when the tire W is linearly rolled by the moving frame 5, the movable table 2 in contact with the tire W moves in the direction of the rotation axis of the tire W and The state is the same as when the slip angle is given.

  Furthermore, when the tire W is rolled to a substantially central position in the moving range of the moving frame 5, the moving speed of the movable table 2 is changed. In other words, in the present embodiment, as shown schematically in FIG. 4, the movement of the tire W relative to the movable table 2 is movable in the second rolling range L2 rather than the first rolling range L1 of the tire W. The moving speed of the table 2 is increased. According to this, the slip angles given to the tires W are different between the first rolling range L1 and the second rolling range L2. That is, the slip angle r1 is applied in the first rolling range L1, and the slip angle r2 is applied in the second rolling range L2.

  In this state, the arithmetic processing means measures, as self-aligning torque, a moment Mz generated around the vertical axis passing through the center of the tire W perpendicular to the road surface among the detection data of the 6-component force sensor 7. The force Fy generated in the horizontal axial direction perpendicular to the traveling direction of the tire W and passing through the center of the tire W is measured as a cornering force (measurement step). That is, here, the self-aligning torque Mz and the cornering force Fy corresponding to the slip angle r1 in the first rolling range L1, and the self-aligning torque Mz corresponding to the slip angle r2 in the second rolling range L2 and Cornering force Fy is collected.

  Thereafter, the arithmetic processing means uses the self-aligning torque Mz and the cornering force Fy detected by the 6-component force sensor 7 in each of the first rolling range L1 and the second rolling range L2 to perform residual cornering. Force is calculated (calculation step).

  At this time, the arithmetic processing means further converts the self-aligning torque Mz and the cornering force Fy detected by the 6-component force sensor 7 into values when the moving speed of the tire W is 80 km / h. Since the moving speed of the moving frame 5 is set to 7 km / h under the control of the control means, the above value with the moving speed set to 80 km / h can be easily converted based on the running resistance at this time. .

The calculation of the residual cornering force will be described in detail. Since the relationship between the self-aligning torque Mz and the cornering force Fy with respect to the slip angle can be expressed by a linear function equation (Fy = aMz + b), as shown in FIG. In the graph in which the cornering force Fy is the vertical axis and the self-aligning torque Mz is the horizontal axis, the coordinates of the two points (Mz ₁ , M) and the self-aligning torque Mz and the cornering force Fy corresponding to the two slip angles r1 and r2. A straight line A is obtained from (Fy ₁ ) and (Mz ₂ , Fy ₂ ). Then, the cornering force Fy when the self-aligning torque Mz is 0 is obtained as the residual cornering force. That is, assuming that the rolling direction of the tire W at this time is the normal rotation direction, as shown in FIG. 5, the normal rotation RCF that is a residual cornering force when the tire W is normally rotated can be obtained.

Further, the moving frame 5 is moved in the reverse direction along the rail 8 at a predetermined speed to roll (reverse) the tire W on the movable table 2. At this time, the self-aligning torque Mz and cornering corresponding to the two slip angles when the tire W is reversed as shown in FIG. 5 by performing the above-described table moving step, measuring step, and calculating step. Since the straight line B is obtained from the coordinates (Mz _1R , Fy _1R ) and (Mz _2R , Fy _2R ) of the two points of the force Fy, the rolling direction of the tire W is set to the reverse direction in the same manner as in the case of the forward rotation. The reverse RCF which is the residual cornering force at the time can be obtained.

When the shape of the tire W to be measured is the same, the rate of change in each of normal rotation and reverse rotation may be obtained in advance as indicated by a broken line in FIG. In this case, when the tire W is rolling on the movable table 2, the moving speed of the movable table 2 is kept constant without changing, and as shown in FIG. Straight lines A, B from a single coordinate (Mz, Fy) of the normal rotation of the self-aligning torque Mz and the cornering force Fy corresponding to a single slip angle and a single coordinate (Mz _R , Fy _R ) of the reverse rotation Can be easily obtained. In this way, the forward rotation RCF can be obtained based on the straight line A, and the reverse rotation RCF can be obtained based on the straight line B.

  Next, a second embodiment of the present invention will be described. The measuring apparatus 10 for carrying out the measuring method of the second embodiment includes a flat table 11 and a tire support shaft that rotatably supports the tire W as shown in a plan view in FIG. 3, a lifting frame 4 that lifts and lowers the tire W via the tire support shaft 3, and a moving frame 5 that moves the tire W via the lifting frame 4. Further, the measuring device 10 is provided with a swinging means 12 that swings the lifting frame 4 with respect to the moving frame 5.

  Unlike the movable table 2 in the measuring apparatus 1 of the first embodiment, the table 11 is fixedly provided on the floor. The swinging means 12 includes a swinging shaft 13 extending in a vertical direction perpendicular to the table 11 and a driving means such as a motor or a cylinder (not shown) for tilting the lifting frame 4 at a predetermined angle with the swinging shaft 13 as a pivot. I have. Since other configurations are the same as those of the measuring apparatus 1 of the first embodiment, the same reference numerals are given in the drawing, and description thereof is omitted.

  When the residual cornering force of the tire W is measured by the measuring device 10, first, the tire W to be measured is attached to the tire support shaft 3 (attachment process), and then the lifting frame 4 is lowered to move the tire W. It press-contacts on the table 2 (load provision process). At this time, the load applied to the tire W is as described in the first embodiment, and is maintained until the end of the measurement.

  Subsequently, the moving frame 5 is moved along the rail 8 at a predetermined speed. Thereby, the tire W rolls on the movable table 2 (tire rolling process). Further, at this time, the elevating frame 4 is tilted by the swinging means 12 (slip angle applying step). As a result, as shown in FIG. 8, the tire W rolls on the table with the slip angle r1 applied. The moving speed and moving distance of the moving frame 5 are the same as those in the first embodiment.

  Furthermore, when the tire W is rolled to a substantially central position in the moving range of the moving frame 5, a different slip angle r2 is given to the tire W by changing the tilt angle of the elevating frame 4. That is, in this embodiment, as schematically shown in FIG. 8, the slip angle in the second rolling range L2 is greater than the slip angle r1 in the first rolling range L1 of the tire W. r2 is large.

  In this state, the arithmetic processing means measures, as self-aligning torque, a moment Mz generated around the vertical axis passing through the center of the tire W perpendicular to the road surface among the detection data of the 6-component force sensor 7. The force Fy generated in the horizontal axial direction perpendicular to the traveling direction of the tire W and passing through the center of the tire W is measured as a cornering force (measurement step).

  Then, the arithmetic processing means uses the self-aligning torque Mz and the cornering force Fy detected by the 6-component force sensor 7 in the first rolling range L1 and the second rolling range L2, respectively, to perform residual cornering. Force is calculated (calculation step).

Thus, based on the graph shown in FIG. 5, the coordinates (Mz ₁ , Fy ₁ ) and (Mz ₂ , Fy ₂ ) of the two points of the self-aligning torque Mz and the cornering force Fy corresponding to the two slip angles r1 and r2 are obtained. ) To obtain the straight cornering force Fy when the self-aligning torque Mz is 0 as the residual cornering force, thereby obtaining the normal rotation RCF that is the residual cornering force when the tire W is forwardly rotated. Can do.

Further, the moving frame 5 is moved in the reverse direction along the rail 8 at a predetermined speed to roll the tire W on the table 11 (reverse rotation). At this time, the self-aligning torque Mz corresponding to two slip angles when the tire W is reversed as shown in FIG. Since the straight line B is obtained from the coordinates (Mz _1R , Fy _1R ) and (Mz _2R , Fy _2R ) of the two points of the cornering force Fy, the rolling direction of the tire W is set in the reverse direction as in the case of the forward rotation. The reverse RCF, which is the residual cornering force when

Also in the second embodiment, as shown in FIG. 6, when the rate of change in each of forward rotation and reverse rotation (indicated by a broken line in FIG. 6) is obtained in advance, the tire W is attached to the table 11. By making the slip angle to be applied to the tire W constant when it is rolling up without changing, a single slip angle in each of forward rotation and reverse rotation, as in the first embodiment. The straight lines A and B can be easily obtained from the single forward rotation coordinates (Mz, Fy) and the reverse rotation single coordinates (Mz _R , Fy _R ) of the self-aligning torque Mz and cornering force Fy corresponding to Can do. Then, the normal rotation RCF can be obtained based on the straight line A, and the reverse rotation RCF can be obtained based on the straight line B.

  W: tire, 2 ... movable table, 3 ... tire support shaft, 11 ... table.

Claims (4)

An attachment process for rotatably attaching the tire to the tire support shaft;
A load applying step of pressing the tire on a flat movable table by applying a predetermined load to the tire via the tire support shaft to which the tire is attached by the attaching step;
Maintaining the pressure contact state of the tire to the movable table by the load applying step, and rolling the tire at a predetermined speed for a predetermined distance; and
A table moving step of moving the movable table in a direction orthogonal to the rolling direction of the tire when the tire is rolling in the tire rolling step;
A measuring step of measuring a self-aligning torque and a cornering force of the tire from the tire rolling on the movable table moved by the table moving step;
And a calculation step of calculating a residual cornering force based on a measurement result of the measurement step. The table moving step changes the moving speed of the movable table when the tire is rolling in the tire rolling step,
The method for measuring a residual cornering force of a tire according to claim 1, wherein the measuring step measures a self-aligning torque and a cornering force that change with a change in a moving speed of the movable table. An attachment process for rotatably attaching the tire to the tire support shaft;
A load applying step of pressing the tire on a flat table by applying a predetermined load to the tire via the tire support shaft to which the tire is attached by the attaching step;
Maintaining the pressure contact state of the tire to the table by the load applying step, and rolling the tire at a predetermined speed for a predetermined distance;
A slip angle imparting step for imparting a slip angle to the tire rolling on the table by the tire rolling step;
A measuring step of measuring self-aligning torque and cornering force of the tire from the tire rolling on the table with the slip angle applied by the slip angle applying step;
And a calculation step of calculating a residual cornering force based on a measurement result of the measurement step. The slip angle applying step changes the slip angle of the tire when the tire is rolling in the tire rolling step,
4. The method for measuring a residual cornering force of a tire according to claim 3, wherein the measuring step measures a self-aligning torque and a cornering force that change with a change in a slip angle of the tire.

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