JP2013124858A - Pressing load setting method for tire uniformity measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressing load setting method for tire uniformity measurement with which a pressing load can be set speedily to a target load value with high accuracy while using a dynamic longitudinal blade constant for each tire.SOLUTION: A pressing load setting method for tire uniformity measurement includes a dynamic longitudinal blade constant calculation step of calculating a dynamic longitudinal blade constant (k) of a tire by dividing an increase amount of a pressing load (p) with a moving amount (d) of relative movement of a rotor and the tire, a deceleration stop moving amount estimation step of estimating a deceleration stop moving amount (δ), a load increase amount calculation step of calculating a load increase amount ΔP from a move stopping command to stop by multiplying the deceleration stop moving amount (δ) by the dynamic longitudinal blade constant (k), a stop command load value calculation step of calculating a stop command load value Ps in issuing a command to stop the relative movement by subtracting the load increase amount ΔP from the target load value P, and a stop command step of issuing a command to stop the relative movement by detecting the time when the pressing load (p) reaches the stop command load value Ps through the relative movement.

Description

  The present invention relates to a method for measuring tire uniformity by rotating a rotating body against a tire and applying a load.

  Various methods for measuring tire uniformity have been proposed in the past (see, for example, Patent Document 1).

JP 2006-105775 A

As described in Patent Document 1, the tire uniformity is measured by rotating the rotating body against the tire and rotating it with a load applied.
In order to accurately measure the tire uniformity, the rotating body must press the tire with a predetermined pressing load for each tire type.

  The rotating body is a relatively heavy object, and the rotating object, which is a heavy object, is moved by driving a drive source such as a motor to press the tire. Even if the movement stop command is issued when the load value is reached and the driving of the drive source is stopped, there is a time lag until the rotating body actually stops, and during that time it moves due to inertia and the pressing load exceeds the predetermined pressing load. Therefore, it is not always easy to accurately set the predetermined pressing load.

  Estimate the amount of movement after the movement stop command, and subtract the load increase obtained by multiplying the estimated movement amount by the vertical spring constant determined in advance for each tire type from the target load value. If calculated, when the pressing load reaches the stop command load value due to the movement of the rotating body, a command to stop the movement is issued, so that the rotating body is stopped approximately at the target load value and set to the predetermined pressing load. Is possible.

However, the longitudinal spring constant used here is a static longitudinal spring constant, not a dynamic longitudinal spring constant in a state where a pressing load is applied, so that the rotating body can be accurately stopped at the target load value. Is not easy.
Therefore, in the past, there have been cases where fine adjustment control has to be repeated once or even several times.

  The present invention has been made in view of the above points, and the object of the present invention is that a rotating body and a tire are accurately obtained with a target load value using a dynamic longitudinal spring constant calculated for each tire to be used for tire uniformity measurement. This is to provide a pressing load setting method of tire uniformity measurement that can be set to the target load value quickly with high accuracy.

In order to achieve the above object, the invention according to claim 1
In a pressing load setting method for setting a pressing load to a predetermined target load value P for rotating and rotating a rotating body against a pivotally supported tire to perform tire uniformity measurement,
A measuring step of measuring a moving amount d and a pressing load p of the relative movement in a process in which the rotating body and the tire move relative to each other and contact with each other to increase the pressing load;
A dynamic longitudinal spring constant calculating step of calculating the dynamic longitudinal spring constant k of the tire by dividing the increase amount of the pressing load p by the movement amount d;
A decelerating stop moving amount estimating step for estimating a decelerating stop moving amount δ from decelerating and stopping from a stop command of relative movement of the tire and the rotating body;
A load increase amount calculating step of multiplying the deceleration stop moving amount δ by the dynamic vertical spring constant k to calculate a load increase amount ΔP from a relative movement stop command to stopping;
A stop command load value calculating step of calculating a stop command load value Ps when issuing a command to stop the relative movement by subtracting the load increase amount ΔP from the target load value P;
And a stop command step for detecting when the pressing load p due to the relative movement between the rotating body and the tire has reached the stop command load value Ps and issuing a command to stop the relative movement. It is a pressing load setting method of measurement.

The invention according to claim 2
In the method for setting the pressing load for tire uniformity measurement according to claim 1,
The dynamic longitudinal spring constant calculation step includes
A dynamic longitudinal spring constant k is calculated in a predetermined load increase period from a predetermined load monitoring start threshold value P1 smaller than the target load value P to a predetermined load monitoring end threshold value P2,
The load monitoring end threshold value P2 is smaller than the assumed stop command load value Ps.

The invention described in claim 3
In the method of setting a pressing load for tire uniformity measurement according to claim 1 or claim 2,
The deceleration stop movement amount estimation step includes:
The deceleration stop moving amount δ is estimated based on a preset deceleration a for the tire type of the measured tire.

The invention according to claim 4
In the method of setting a pressing load for tire uniformity measurement according to any one of claims 1 to 3,
After the stop command step,
A load average value measuring step of measuring the load average value Pa of the pressing load by rotating the tire in a state where the relative movement is stopped at least once;
A determination step of determining whether or not the load average value Pa is within an allowable range;
A position adjustment amount calculation step of calculating a position adjustment amount e using the dynamic longitudinal spring constant k when it is determined in the determination step that the load average value Pa is not within an allowable range;
And a fine adjustment step of performing fine adjustment by relatively moving the position adjustment amount e.

The invention according to claim 5
In the pressing load setting method of tire uniformity measurement according to claim 4,
The position adjustment amount calculation step includes:
The position adjustment amount e is calculated by dividing the difference between the target load value P and the load average value Pa by the longitudinal spring constant k.

  According to the method of setting a pressing load for tire uniformity measurement according to claim 1, the moving amount d and the pressing load p of the relative movement between the rotating body and the tire are measured in the measuring step, and the rate of increase of the pressing load p is determined as the moving amount d. The dynamic vertical spring constant k is obtained by dividing by, and the dynamic vertical spring constant k is multiplied by the deceleration stop movement amount δ to calculate the load increase amount ΔP, and the load increase amount ΔP is subtracted from the target load value P. Since the stop command load value Ps is obtained, by issuing a command to stop the relative movement when the pressing load p reaches the stop command load value Ps, the relative movement is accurately stopped at the target load value P. The target load value can be quickly set with high accuracy, and high-precision tire uniformity measurement can be quickly entered.

  According to the method for setting the pressure load for tire uniformity measurement according to claim 2, the predetermined load monitoring end that is smaller than the stop command load value Ps assumed from the predetermined load monitoring start threshold value P1 smaller than the target load value P. Since the dynamic longitudinal spring constant k is calculated during a predetermined load increase period up to the threshold value P2, the dynamic longitudinal spring constant k can be calculated accurately with a stable load increase, and the stop command load can be calculated from the dynamic longitudinal spring constant k. The stop control can be performed with a margin by calculating the value Ps.

  According to the method of setting a pressing load for tire uniformity measurement according to claim 3, it is possible to determine the deceleration stop movement amount δ for each tire type, and based on a preset deceleration a for the tire type of the tire to be measured. Thus, the deceleration stop movement amount δ can be estimated.

  According to the method for setting a pressing load for tire uniformity measurement according to claim 4, after the stop command step, the load in which the relative movement is stopped is rotated at least once and the load average value Pa of the pressing load is measured. When the average value measuring step, the determining step for determining whether or not the load average value Pa is within the allowable range, and the determination step determining that the load average value Pa is not within the allowable range, Since the position adjustment amount calculating step for calculating the position adjustment amount e using the spring constant k and the fine adjustment step for performing the fine adjustment by relatively moving by the position adjustment amount e are provided after the stop command step (coarse adjustment control). After), when it is determined in the determination step that the load average value Pa is within the allowable range, it is not necessary to perform the fine adjustment step, and the pressing load setting is completed, and the load average value Pa is within the allowable range in the determination step. It was determined that it was not within In addition, the position adjustment amount e can be accurately calculated using the dynamic longitudinal spring constant k calculated in the previous pressing load setting (coarse adjustment control). Since the adjustment is performed, fine adjustment is not performed again and the setting of the pressing load can be completed, and the target load value can be quickly set with high accuracy.

  According to the method for setting the pressing load for tire uniformity measurement according to claim 5, the position adjustment amount e is calculated by dividing the difference between the target load value P and the load average value Pa by the longitudinal spring constant k. The accuracy of the position adjustment amount e is high.

It is the principal part perspective view which extracted only the principal part of the tire uniformity measuring apparatus. It is the graph which showed the raise change of the press load accompanying the movement of a load roll. It is a flowchart which shows the control procedure of this press load setting control.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of a main part in which only a main part of the tire uniformity measuring device 1 is extracted and illustrated.
The tire 2 is sandwiched between upper and lower rims 3 and 4 with upper and lower bead portions held in a horizontal posture, and centered on rim shafts 3 a and 4 a that extend coaxially from the upper and lower rims 3 and 4. The rim shafts 3 a and 4 a are driven to rotate by an electric motor (not shown), and the tire 2 rotates via the upper and lower rims 3 and 4.

On the other hand, a road roll 10 which is a flat columnar rotating body along with the tire 2 is rotatably supported by a central support shaft 11 which is parallel to the rim shafts 3a and 4a and oriented in the vertical direction in a horizontal posture. .
Although not shown in the figure, the center support shaft 11 is vertically supported with the load roll 10 interposed therebetween, and the center support shaft 11 approaches and separates from the rim shafts 3a and 4a on the tire 2 side in the state of being supported. A position sensor (not shown) can measure the movement amount d.
The tire 2 may be moved and pressed against the road roll 10.

In addition, a load cell (not shown) is provided on the bearing portion of the center support shaft 11 of the load roll 10, and the pressing load p when the load roll 10 is pressed against the tire 2 can be measured.
Note that a load cell may be provided in the bearing portions of the rim shafts 3a and 4a that support the tire 2, and the pressing load p by the load roll 10 may be measured.
When the tire 2 is rotated in a state where the outer peripheral surface with which the tire 2 is in contact is pressed and pressed against the tire 2, the road roll 10 is rotated without causing slippage on the pressing surface.

The movement of the road roll 10 and the rotation of the tire 2 are driven and controlled by a control device (not shown).
Measured information such as the moving distance d and the pressing load p is input to the control device, and is subjected to calculation processing to control the movement of the road roll 10 and the rotation of the tire 2 and to measure the tire uniformity.

  Tire uniformity such as the magnitude of radial force variation (RFV) and the lateral force (axial direction) of tire force LFV (Lateral Force Variation) The tire 2 is measured by rotating the tire 2 in a state where the pressure to 2 is accurately set to a predetermined pressing load determined for each tire type.

In order to accurately measure the tire uniformity, it is necessary to set the pressing load on the tire 2 by the road roll 10 to a predetermined pressing load with high accuracy.
Therefore, in the tire load uniformity measurement pressing load setting method according to the present embodiment, the control device performs control according to the control procedure shown in the flowchart shown in FIG.

Immediately before entering the pressing load setting control, the road roll 10 is at a predetermined position away from the tire 2.
Referring to the flowchart of FIG. 3, in step 1, it is determined whether or not there is a load control command that enters control for setting a predetermined pressing load for tire uniformity measurement. If there is no load control command, the present control routine is exited. If this control is not executed and there is a load control command, the process proceeds to step 2 to determine whether or not the fine adjustment control flag F is “1”. If “1” is not set and “0” is set. For example, the process proceeds to step 3 to enter coarse adjustment control. If “1” is set, the process jumps to step 21 to enter fine adjustment control.

Initially, the fine adjustment control flag F is “0”. When the process proceeds from step 2 to step 3 and coarse adjustment control is entered, the road roll 10 is moved toward the tire 2.
In step 4, the moving amount d and the pressing load p of the load roll 10 are read, and the change of the pressing load p is monitored.

FIG. 2 is a graph showing an increase in the pressing load p after the load roll 10 moves and contacts the tire 2 and a pressing load is generated.
The load roll 10 moves at a substantially constant speed except immediately after the start of movement and immediately before the movement is stopped.
The tire 2 is elastically deformed by being pressed by the road roll 10, but the initial spring force when the road roll 10 is in contact with the tire 2 is small, and the increase in the pressing load p is slow, and thereafter the slope becomes steep. By rising and stopping the movement of the road roll 10, the target load value P determined for each tire type is settled.

The change in load is monitored during a predetermined load increase period from a predetermined load monitoring start threshold value P1 at which the increase of the pressing load p becomes steep to a predetermined load monitoring end threshold value P2 that is approximately 20 to 30% lower than the target load value P. Based on this, the dynamic longitudinal spring constant k is calculated.
The load monitoring end threshold value P2 is a value sufficiently smaller than the stop command load value Ps assumed to be smaller than the stop command load value Ps calculated in step 12 later.

  That is, in the flowchart of FIG. 3, coarse control is entered, the load roll 10 moves in step 3, and when the moving amount d and the pressure load p of the load roll 10 are read in step 4, the pressure load p is read in step 5. Is determined whether or not the load monitoring start threshold value P1 has been reached. While the pressing load p does not reach the load monitoring start threshold value P1, this control routine is exited and the process returns to step 1 and when the load monitoring start threshold value P1 is reached. The process proceeds to step 6 to determine whether or not “1” is set in the load monitoring end flag G. If “1” is not set and “0”, the process proceeds to step 7 and “1” is set. If so, jump to step 14.

When the load monitoring end flag G is “0” and the process proceeds to step 7, it is determined whether or not the dynamic longitudinal spring constant k can be calculated.
Since the dynamic longitudinal spring constant k is calculated by dividing the increase amount of the pressing load p by the moving amount d, the average of the pressing load p with the average moving amount in a stable state within a predetermined load increasing period. The dynamic longitudinal spring constant k can be calculated when a specific increase amount is required.

  Therefore, the process jumps from Step 7 to Step 9 until the dynamic longitudinal spring constant k can be calculated, and when the dynamic longitudinal spring constant k can be calculated, the process proceeds to Step 8 and the average of the pressing load p with an average moving amount is obtained. The dynamic longitudinal spring constant k is calculated by dividing the general increase amount, and the process proceeds to step 9.

  In step 9, it is determined whether or not the pressing load p has reached the load monitoring end threshold value P2. While the pressing load p does not reach the load monitoring end threshold value P2, this control routine is exited and the process returns to step 1 to press the pressing load p. Monitoring of the change of the load p is continued, and when the load monitoring end threshold value P2 is reached, the process proceeds to step 10 and the movement of the load roll 10 is stopped based on the dynamic longitudinal spring constant k in the steps 10 to 12. A control value (stop command load value Ps) is calculated, and “1” is set to the load monitoring end flag G in step 13, and the process proceeds to step 14.

  Therefore, after the pressing load p reaches the load monitoring end threshold value P2 and the stop command load value Ps is calculated, “1” is set in the load monitoring end flag G (step 13), and from step 6 to steps 7 to 13 thereafter. Will be skipped to step 14.

In step 10, which is the first step of calculating the stop command load value Ps, a deceleration stop moving amount δ from the stop command until the load roll 10 decelerates and stops is estimated.
Since the target load value P is determined for each tire type and the moving speed of the load roll 10 is known when a stop command is issued, the deceleration a and deceleration stop when decelerating and stopping for each tire type are known. The time t to be set is preset and stored.
Therefore, to extract the deceleration a and the deceleration stopping time t based on the tire type of the measured tire, calculating a deceleration stop movement amount [delta] from the deceleration a and the deceleration stop time t (δ = a · t 2 /2) And can be estimated.

In the next step 11, the amount of increase in load ΔP (= k · δ) from the stop command until the load roll 10 stops is multiplied by multiplying the deceleration stop moving amount δ by the dynamic longitudinal spring constant k calculated in step 8. In step 12, the load increase amount ΔP is subtracted from the target load value P to calculate a stop command load value Ps (= P−ΔP).
When the stop command load value Ps is calculated, “1” is set to the load monitoring end flag G (step 13).

  In step 14, it is determined whether or not the pressing load p reaches the stop command load value Ps calculated in step 12. If the pressing load p reaches the stop command load value Ps, the present control routine is exited and the process returns to step 1. Until the pressing load p exceeds the load monitoring end threshold value P2 and reaches the stop command load value Ps, the process jumps from Step 6 to Step 14 and waits for the pressing load p to reach the stop command load value Ps.

  When the pressing load p reaches the stop command load value Ps, the process proceeds to step 15 to output a movement stop command for the load roll 10 and finish the coarse adjustment control. Then, the load monitoring end flag G is set to “0”. (Step 16), the fine control flag F is set to “1” (step 17), and the process returns to step 1.

  Since the load increase amount ΔP until the load roll 10 stops is calculated from the stop command based on the vertical spring constant k specific to the measured tire 2 obtained from the increase amount of the movement amount d and the pressing load p, the load increase The amount ΔP is the load increase amount ΔP of the tire 2 to be measured, and the stop command load value Ps obtained by subtracting the estimated load increase amount ΔP from the target load value P is also a stop command load value with high accuracy peculiar to the tire 2 to be measured. Ps.

  When the pressing load p reaches the optimum stop command load value Ps for the tire 2 to be measured, by issuing a movement stop command for the load roll 10, the pressing load p when the load roll 10 is actually stopped is set as the target. Coarse tone control with high accuracy very close to the load value P is performed.

  Referring to FIG. 2, even if the pressing load p reaches the stop command load value Ps and a movement stop command for the load roll 10 is issued, the load is moved until it actually stops due to the inertia of the load roll 10. However, the pressure load p when stopped is very close to the target load value P. However, the pressure load p is very close to the target load value P.

As described above, since the coarse adjustment control is performed and the movement stop command for the load roll 10 is issued, the fine adjustment control flag F is set to “1” with reference to the flowchart of FIG. Step 21 is entered and fine control is entered.
First, in step 21, the load roll 10 is rotated, the pressing loads p at a plurality of rotation angles are sequentially read (step 22), and a load average value Pa that is an average of the plurality of pressing loads p read in step 23 is calculated.

The load roll 10 rotates at least once and calculates an average value (load average value Pa) of the pressing load p at each rotation angle.
Then, in the next step 24, it is determined whether or not the load average value Pa is within an allowable range, that is, whether or not the difference (| P−Pa |) between the load average value Pa and the target load value P is equal to or smaller than a predetermined minute value ε. If the load average value Pa is within the allowable range (| P−Pa | ≦ ε), the process jumps to step 27 to end the fine control, cancel the load control command, and set the fine control flag F to “0” ( Step 28), the final pressing load setting control ends, and the process returns to Step 1 anew.

  However, if it is determined in step 24 that the load average value Pa is not within the allowable range (| P−Pa |> ε), the process proceeds to step 25 where the difference obtained by subtracting the load average value Pa from the target load value P is determined. The position adjustment amount e (= (P−Pa) / k) is calculated by dividing (P−Pa) by the dynamic longitudinal spring constant k calculated in step 8 in the previous coarse adjustment control. Fine adjustment is performed by moving the load roll 10 by the position adjustment amount e, the control routine is exited, and the process returns to step 1.

When the fine adjustment is performed, the fine adjustment control flag F remains “1”, so the flow jumps from step 2 to step 21 to rotate the load roll 10 again and read the pressing load p at a plurality of rotation angles ( In step 22), the load average value Pa is calculated (step 23), and in step 24, it is determined whether or not the load average value Pa is within the allowable range.
If the load average value Pa is within the allowable range, the process jumps to step 27 and the present load control is terminated. If the load average value Pa is not within the allowable range, the flow proceeds to steps 25 and 26 and fine adjustment is performed again. Thus, fine adjustment is repeatedly performed until the load average value Pa is within the allowable range.

  In this pressing load setting control, at the stage of coarse adjustment control, a movement stop command for the load roll 10 is issued based on the stop command load value Ps optimum for the tire 2 to be measured, and the pressing load p is very close to the target load value P. Since it can be stopped with high accuracy, even if fine control is entered, the load average value Pa is within the allowable range, and it is not necessary to perform actual fine adjustment, or fine adjustment can be completed almost once. it can.

  In this way, since the number of fine adjustments in the pressing load setting control is 0 to 1 time, the pressing load setting control does not affect the cycle time of the tire uniformity measurement, and promptly shifts to the tire uniformity measurement. be able to.

  DESCRIPTION OF SYMBOLS 1 ... Tire uniformity measuring apparatus, 2 ... Tire, 3, 4 ... Rim, 3a, 4a ... Rim axis | shaft, 10 ... Road roll, 11 ... Center spindle

Claims (5)

In a pressing load setting method for setting a pressing load to a predetermined target load value P for rotating and rotating a rotating body against a pivotally supported tire to perform tire uniformity measurement,
A measuring step for measuring the moving amount d and the pressing load p of the relative movement in a process in which the rotating body and the tire move relative to each other and contact with each other to increase the pressing load;
A dynamic longitudinal spring constant calculating step of calculating the dynamic longitudinal spring constant k of the tire by dividing the increase amount of the pressing load p by the movement amount d;
A decelerating stop moving amount estimating step for estimating a decelerating stop moving amount δ from decelerating and stopping from the relative movement stop command of the tire and the rotating body;
A load increase amount calculating step of multiplying the deceleration stop moving amount δ by the dynamic vertical spring constant k to calculate a load increase amount ΔP from a relative movement stop command to stopping;
A stop command load value calculating step of calculating a stop command load value Ps when issuing a command to stop the relative movement by subtracting the load increase amount ΔP from the target load value P;
And a stop command step for detecting when the pressing load p due to the relative movement of the rotating body and the tire has reached the stop command load value Ps and issuing a command to stop the relative movement. How to set the pressing load for uniformity measurement. The dynamic longitudinal spring constant calculation step includes
A dynamic longitudinal spring constant k is calculated in a predetermined load increase period from a predetermined load monitoring start threshold value P1 smaller than the target load value P to a predetermined load monitoring end threshold value P2,
2. The method for setting a pressing load for tire uniformity measurement according to claim 1, wherein the load monitoring end threshold value P2 is smaller than the assumed stop command load value Ps. The deceleration stop movement amount estimation step includes:
3. The method for setting a pressing load for tire uniformity measurement according to claim 1, wherein the deceleration stop movement amount δ is estimated based on a preset deceleration a for the tire type of the measured tire. After the stop command step,
A load average value measuring step of measuring the load average value Pa of the pressing load by rotating the tire in a state where the relative movement is stopped at least once;
A determination step of determining whether or not the load average value Pa is within an allowable range;
A position adjustment amount calculation step of calculating a position adjustment amount e using the dynamic longitudinal spring constant k when it is determined in the determination step that the load average value Pa is not within an allowable range;
4. The method for setting a pressing load for tire uniformity measurement according to any one of claims 1 to 3, further comprising a fine adjustment step of performing a fine adjustment by relatively moving the position adjustment amount e. The position adjustment amount calculation step includes:
5. The method for setting a pressing load for tire uniformity measurement according to claim 4, wherein the position adjustment amount e is calculated by dividing a difference between the target load value P and the load average value Pa by the longitudinal spring constant k. .

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