JP2008089467A - Method for inspecting precision of tire testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the burden of workers and know the substantial precision of a tire testing machine. <P>SOLUTION: A method for inspecting the precision of the tire testing machine has a rotating radius different from a drum 42 and higher circularity than a tire T in place of the tire T, mounts a dummy tire 60 having rigidity capable of maintaining circularity on a spindle shaft 11 even when receiving load in a radial direction, and measure variation load generated by rotating the dummy tire 60 while giving load from the drum 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an accuracy inspection method for inspecting the measurement accuracy of a tire testing machine itself when the tire testing machine is shipped.

  A traveling vehicle is affected by a fluctuating load (referred to as force variation) acting on a tire rotating on a road surface. The fluctuating load is generated due to the hardness of rubber forming the tire, uneven thickness of the tire, the roundness of the tire, and the like. Of these fluctuating loads, those that are not particularly desired to be generated as a cause of vibrations or abnormal noise that adversely affect the vehicle, such as fluctuating loads in the tire radial direction (radial force variation, hereinafter referred to as RFV), fluctuations in the tire width direction The load (lateral force variation, hereinafter referred to as LFV) and the tire tangential variable load (tractive force variation, hereinafter referred to as TFV) can be mentioned.

  A tire uniformity measuring device (hereinafter referred to as a tire testing machine) includes a spindle shaft on which a tire can be mounted, and a drum having a drum shaft parallel to the spindle shaft. By attaching the tire with the rim assembled to the spindle shaft and pressing the tire against the drum, a radial load is applied to the tire, and in this state, the distance between the spindle shaft and the drum shaft is fixed and the tire is rotated. Measure the fluctuating load as described above. In the tire testing machine, a slight mounting angle or positional deviation of each part in the apparatus is reflected in the fluctuating load. For this reason, extremely high measurement accuracy is required for this type of tire testing machine.

  Conventionally, in order to confirm whether or not the tire testing machine to be shipped has the required measurement accuracy, the data is obtained using statistical methods based on data obtained by repeatedly measuring a large number of tires in order at appropriate times. An inspection method has been implemented in which the accuracy of a tire testing machine is inspected by checking whether or not the range of variation is a predetermined value or less. As an inspection method of this kind, 10 tires are repeatedly measured 10 times sequentially, and based on a total of 100 data, variance analysis is performed by two factors, between tires and between measurement times, and the residual There is known a 10 × 10 (tenbiten) test for confirming whether the standard deviation of (experimental error, measurement error) is within a specified value.

However, the 10 × 10 test requires a great amount of test time, and the tires must be replaced manually for each test, and the occurrence of measurement errors due to a large number of tests cannot be excluded. Further, since tire replacement has to be performed 100 times per tire testing machine, the worker's physical and mental fatigue is extremely large.
Therefore, in order to reduce measurement errors caused by tire replacement and operator fatigue, in Patent Document 1, in order to efficiently perform 10 measurements for one tire, An apparatus configuration that can automatically change the mounting angle of the tire is disclosed.
JP-A 64-66536

However, even in the apparatus configuration of the above-mentioned Patent Document 1, the worker must perform the replacement work of the ten tires, and the problem that the labor of the worker and the time required for the inspection are not completely solved.
Further, in a tire testing machine that requires measurement accuracy at a high speed uniformity (high rotational speed test) necessary for measuring TFV, the tire rotational speed for measuring TFV is not stipulated. It is necessary to perform a 10 × 10 test under a plurality of rotational speeds for the purpose of verifying the resonance relationship between the rotational speed of the tire and the natural frequency of the tire testing machine. For this reason, the measurement data obtained from one tire testing machine is enormous, and there is a problem that the processing of the data takes a lot of time and is extremely inefficient.

Further, the 10 × 10 test can be indirectly known by a statistical method of the accuracy of the tire testing machine, and it cannot be denied that there is a slight difference between the actual accuracy of the tire testing machine. .
Accordingly, the present invention provides a new method for checking the accuracy of a tire testing machine that can reduce the burden on the operator and can know the actual accuracy of the tire testing machine.

In order to achieve the above object, the present invention takes the following technical means.
That is, the technical means for solving the problems in the present invention include a spindle shaft on which a tire can be mounted, and a drum that rotates around a drum shaft parallel to the spindle shaft and is pressed against the tire to apply a load to the tire. And an accuracy inspection method of a tire testing machine comprising a measuring device that measures a fluctuating load generated by rotating the tire while pressing a drum against the tire,
Instead of the tire, a dummy tire having a rotation radius different from that of the drum and a roundness higher than that of the tire and having rigidity capable of maintaining the roundness even when the load is received in a radial direction. Is mounted on the spindle shaft, and the variable load generated by rotating the dummy tire with a load from the drum is measured by the measuring device.

  According to this, when the dummy tire is rotated with a load from the drum, the fluctuating load that is measured theoretically becomes zero. The fact that the fluctuating load is not measured means that the tire testing machine is formed with extremely high accuracy, and the fluctuating load measured by the tire testing machine does not include any fluctuating load due to the equipment configuration of the tire testing machine. Indicates. In an actual tire testing machine, some value is measured by the above test method. In this case, the measured value itself becomes the measurement accuracy of the tire testing machine. Thus, according to the above method, the accuracy of the tire testing machine can be inspected by performing the test with the dummy tire once.

In addition, according to the above inspection method, since the fluctuating load measured by bringing the dummy tire into contact with the drum can be made the accuracy of the tire testing machine, the accuracy caused by the tire testing machine can be substantially grasped. It will be possible.
Also, in order to inspect the resonance relationship between the tire rotation speed and the natural frequency of the tire testing machine, even when a high-speed uniformity test is performed at a plurality of rotation speeds, each test is performed only once. Inspection can be performed, and the working time can be shortened.
In practice, the fluctuating load measured by bringing the dummy tire into contact with the drum measures the fluctuating load caused by bringing the dummy tire into direct contact with the drum in addition to the fluctuating load caused by the tire testing machine. Will be. The contact variation load corresponds to the radius variation of the dummy tire multiplied by the rigidity between the contact portion of the dummy tire and the drum, and should be ignored in the accuracy inspection of the tire testing machine itself.

  By the way, it is practically difficult to manufacture a perfect circular dummy tire, and even when a perfect circular dummy tire is prepared, the dummy tire is slightly misaligned with the spindle shaft. It may be attached in a state. In such a case, the radius variation of the dummy tire is large and the contact variation load may be increased. In general, the drum is made of a hard material such as a metal. When the dummy tire having rigidity as described above is brought into contact with the drum and rotated, the wear of the dummy tire and the drum is increased, which is preferable. Absent.

In view of this point, it is preferable to rotate the dummy tire after interposing a shock absorber having a lower rigidity than the dummy tire between the dummy tire and the drum.
Thereby, the contact rigidity between the dummy tire and the drum can be reduced, and the contact fluctuation load caused by the radial fluctuation of the dummy tire can be reduced as much as possible.
In general, a measuring device of a tire testing machine measures a fluctuating load generated by rotating a rotating body (for example, a tire) attached to a spindle shaft, and the rotational speed component of the rotating body is measured from the measured load. And a harmonic component is extracted by frequency analysis.

For this reason, for example, when a dummy tire is mounted on the spindle shaft, and the variable load of the dummy tire is measured in a state where the dummy tire is in contact with the buffer rotating at the same cycle as the dummy tire, the non-uniformity of the buffer Fluctuating load caused by roundness error and roundness error also appears in the vicinity of the rotational speed component of the dummy tire, and this causes the fluctuating load caused by the dummy tire and the fluctuating load caused by the buffer to be combined and measured. There is a possibility that it is difficult to determine which of the fluctuating loads are due to the dummy tire because the fluctuating loads are too close to each other.
Therefore, in the present invention, the shock absorber is rotated at a different period from the dummy tire, thereby causing the variable load caused by the shock absorber to appear in a different rotational speed component than the dummy tire, and the variable load is This prevents the fluctuating load and the fluctuating load resulting from the dummy tire from being combined in the rotational speed component of the dummy tire.

Further, it is preferable that the buffer is wound around the drum and rotated together with the drum.
Thus, the shock absorber can be easily arranged between the dummy tire and the drum, and the shock absorber can be rotated at a different period from that of the dummy tire.
The shock absorber is pivotally supported by a rotation shaft parallel to the spindle shaft, and has a rotation radius around the rotation shaft that is different from that of the dummy tire and rotates at a different period from the dummy tire. Formed,
It is preferable that the shock absorber is rotated together with the dummy tire and the drum while being sandwiched between the dummy tire and the drum.

According to this, a portion having a lower contact rigidity than the dummy tire can be formed thick in the radial direction of the buffer body, and the contact rigidity with the dummy tire can be further reduced.
Further, for example, a tire or the like can be substituted as the buffer body, and not only can the buffer body be arranged between the dummy tire and the drum very easily, but also the buffer body can be easily replaced.
The measuring device measures the fluctuating load with the spindle shaft,
The dummy tire includes a weight attaching portion capable of attaching a weight at one or a plurality of positions in a radially outward direction from a rotation center supported by the spindle shaft.
It is preferable that the dummy tire is rotated in a state where the weight is attached to or removed from the weight attaching portion and the center of gravity of the dummy tire is shifted from the rotation center, and the variable load is measured on the spindle side by the measuring device.

According to this, the center of gravity can be decentered with respect to the rotation center of the dummy tire. Also, the weight and position of the weight can be set by the operator. For this reason, the unbalance force generated by rotating the dummy tire having the eccentric center of gravity can be made known. As a result, the accuracy of the tire testing machine can be inspected by comparing the fluctuating load generated by the rotation of the dummy tire and measured by a load cell or the like provided in the measuring device with the unbalance force.
Here, the unbalance force acts on the load cell that supports the spindle shaft and also acts on the shock absorber that contacts the dummy tire. Since the rigidity of the load cell is significantly larger than the rigidity of the buffer body, almost all unbalance force acts on the load cell.

Therefore, as described above, the variable load is measured on the spindle shaft by the measuring device, and thereby the unbalance force is more accurately measured.
The measuring device measures the fluctuating load on the spindle shaft side,
The shock absorber includes a roll that rotates around a rotation axis parallel to the spindle shaft in contact with the dummy tire, and an elastic support device that elastically presses and supports the roll against the dummy tire,
It is preferable that the dummy tire is rotated in a state where the roll is in contact with the dummy tire from the drum side, and the variable load is measured on the spindle side by the measuring device.

According to this, by the elastic force of the elastic support device (buffer body), the roll can follow the radius variation of the dummy tire accompanying the rotation, thereby keeping the contact rigidity between the dummy tire and the roll uniform. Can do. Thereby, generation | occurrence | production of the said contact fluctuation load can be suppressed and an accurate measurement can be performed.
Moreover, it is preferable that the said roll is supported so that the movement to the axial direction of the said rotating shaft is possible.
According to this, even when the dummy tire and the drum rotate while the drum is slightly tilted with respect to the dummy tire due to a slight parallelism error between the spindle shaft and the drum shaft, the shock absorber is the shaft of the rotating shaft. By moving in the direction, it is possible to follow the deviation in the rotation of the drum accompanying such a shaft runout. As a result, the variation in the radius is absorbed well by the buffer body, and the generation of the fluctuating load is suppressed, so that a more accurate inspection can be performed.

Further, the dummy tire includes a weight attaching portion capable of attaching a weight at one or a plurality of positions in a radially outward direction from a rotation center supported by the spindle shaft.
It is preferable to rotate the dummy tire in a state where the weight is attached to or removed from the weight attaching portion and the center of gravity of the dummy tire is shifted from the center of rotation.

  According to the accuracy test method for a tire testing machine according to the present invention, the burden on the operator can be reduced and the substantial accuracy of the tire testing machine can be known.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[First Embodiment]
As shown in FIG. 1, the tire testing machine 1 according to the present embodiment includes a tire rolling device 2 on which a tire T can be mounted, a drum device 3 disposed on the side of the tire rolling device 2, and these tires. A processing control device 4 that controls the rolling device 2 and the drum device 3 and processes data obtained from the both devices 2 and 3 is provided.
The tire rolling device 2 includes a spindle shaft 11 extending in the vertical direction and a support 12 that rotatably supports the spindle shaft 11. A rim 13 for mounting the tire T can be disposed on the upper end portion of the spindle shaft 11, and the tire T is disposed on the tire rolling device 2 by mounting the tire T on the rim 13. Can do.

The support body 12 includes a support base 16, a cylindrical housing 17 erected on the support base 16, and a cylindrical bearing housing 18 accommodated in the housing 17. The bearing housing 18 is accommodated in the housing 17 with its upper end protruding from the housing 17.
The spindle shaft 11 is housed in the bearing housing 18 with the upper end portion protruding from the bearing housing 18. Further, the spindle shaft 11 is supported by the bearing housing 18 via a pair of upper and lower bearings in a state in which the shaft center thereof coincides with the shaft center of the bearing housing 18.

The drum device 3 includes a cylindrical drum 42 having a substitute road surface body 41 on the outer peripheral surface, a drum shaft 43 attached to the axis of the drum 42, a frame 44 that pivotally supports the drum shaft 43, And a driving device 45 that rotates the drum 42 by applying a rotational force to the drum shaft 43. The drum 42 can be moved close to and away from the spindle shaft 11 by a servo motor, a screw jack (not shown) or the like together with the frame 44.
A known device is used as the drive device 45. For example, a pulley provided at one end of the drum shaft 43, a drive motor mounted on the end surface of the frame 44, and a shaft of the drive motor. The pulley includes a mounted pulley and a V belt wound around the pair of pulleys.

The processing control device 4 includes a control unit 51 that controls the tire rolling device 2 and the drum device 3, and a measuring device 52 that measures a fluctuating load generated when the tire T rotates.
The measuring device 52 is provided in the tire rolling device 2 to measure each fluctuating load (RFV, LFV, TFV) acting on the tire T, and a rotational speed measuring means for measuring the rotational speed of the tire ( (Not shown) and a calculation means 54 that is connected to the measuring instrument 53 and the rotation speed measurement means and calculates a fluctuating load generated when the tire T rotates.
The measuring device 53 includes a plurality of load cells 55 disposed between the housing 17 and the bearing housing 18 of the tire rolling device 2, and a load cell that is connected to the plurality of load cells 55 and amplifies signals from the plurality of load cells 55. And an amplifier 56.

The plurality of load cells 55 are arranged on the upper end side and the lower end side of the bearing housing 18. A plurality (for example, four) of the plurality of load cells 55 arranged in the bearing housing 18 are arranged on the circumference centered on the axis of the spindle shaft 11 at equal intervals.
Further, a flange that protrudes radially outward of the bearing housing 18 and overlaps the upper end of the housing 17 is formed at the upper end of the bearing housing 18, and a plurality of load cells 55 are formed between the flange and the upper end of the housing 17. It is also possible to adopt a configuration in which the above is deployed as described above.
Signals from the plurality of load cells 55 are sent to the load cell amplifier 56 and amplified. The signal includes a DC component and a variable component for the variable load of the tire T, and is separated into a DC component and a variable component by passing through a high-pass filter provided in the load cell amplifier 56 or separately. It is sent to the calculation means 54.

In the calculating means 54, processing such as frequency analysis and tracking analysis is performed based on the fluctuating load obtained from the measuring device 53 and the rotational speed of the tire T obtained from the rotational speed measuring means. As a result, the rotational speed component of the tire T and its harmonic components can be extracted from the variable load components acting on the tire T.
2A and 2B show the results of FFT conversion of the fluctuating load obtained from the measuring instrument 53, where the horizontal axis indicates the frequency and the vertical axis indicates the fluctuating load magnitude.
As shown in FIG. 2A, if the ratio between the rotation periods of the tire T and the drum 42 is sufficiently different, the variable load (B _{1 to} B ₃ ) in the rotation speed component of the tire T and the rotation speed of the drum 42 The variable load (A _{1 to} A ₅ ) in the component is sufficiently separated. Thereby, it is possible to easily discriminate the variable load at each frequency component of the tire T from other variable loads, and extract only the variable load at each frequency component of the tire T.

On the other hand, FIG. 2B shows the result when the ratio of the diameter of the drum 42 to the diameter of the tire T is 5: 3. In this case, as is apparent from the figure, the five-fold component of the tire rotational speed matches the frequency three times the drum rotational speed, so that the fluctuating load observed at the five-fold component of the tire rotational speed is Of the variable loads caused by the non-uniformity of the drum 42, the variable load having a component three times the drum rotation speed is added to the variable load generated in the tire T itself (B ₃ + A ₅ ). In such a case, an error component of a component five times the tire T rotation speed cannot be correctly evaluated.
Therefore, it is necessary to set the diameter of the tire T and the diameter of the drum 42 so that the multiple component of the rotation speed of the tire T and the drum 42 is less than the analysis target multiple component and does not have the least common multiple relationship. The ratio of the diameters of the tire T and the drum 42 is, for example, 11:17.

In the present embodiment, the load cell 55 can be arranged in the drum device 3 to measure the fluctuating load on the drum shaft 43 side. In this case, it is necessary to apply driving to the tire T. is there.
Further, an external input means 57 is connected to the processing control device 4.
The tire testing machine 1 according to the inspection method of the present invention has the above configuration.
In the test of the tire T using the tire testing machine 1, the tire T is mounted on the rim 13 of the spindle shaft 11, the drum device 3 is brought close to the tire rolling device 2, and the substitute road surface body 41 of the drum 42 is used as the tire. A load is applied from the drum 42 toward the tire T by pressing against the tread surface of the T, and the tire T is rotated by rotating the drum 42 in a state where the distance between the spindle shaft 11 and the drum shaft 43 is kept constant. The variable load generated by this is measured by the measuring device 52.

Usually, there is variation in the data of the fluctuating load measured in this way. For example, even if the tire T is the same, the obtained data may vary by changing the mounting angle with respect to the spindle shaft 11.
Moreover, since the measuring device 52 detects the load fluctuation at the time of a test and measures it,
The measured variable load includes not only the variable load due to the rotation of the tire T but also the variable load resulting from the tire testing machine 1 in the variable load.
In view of this point, it is conceivable that the variation in data of the variable load is caused by the variable load resulting from the tire testing machine 1 being included in the variable load to be measured. The cause of the fluctuating load caused by the tire testing machine 1 is a mechanical error or an electrical error in the apparatus. A mechanical error occurs when the accuracy of the spindle shaft 11 is poor, the load generated from the bearing that supports the spindle shaft 11, the rotation speed of the tire T, or its double component is close to the natural frequency of the tire testing machine 1. This is thought to be due to vibration (load). Further, the electrical error may be influenced by the measurement accuracy of the load cell 55 that measures the fluctuating load and the electrical noise mixed in the signal line. These errors vary slightly depending on the implementation status of the test and are difficult to quantify. Further, it is extremely difficult to completely eliminate errors inevitably inherent in the tire testing machine 1.

The present invention examines the accuracy of the tire testing machine 1 itself by grasping the magnitude of the fluctuating load that appears due to the error inherent in the tire testing machine 1. The inspection is performed by performing the following test one or more times.
First, a dummy tire 60 is mounted on the spindle shaft 11 instead of the tire T.
Here, the dummy tire 60 is formed in a circular shape having a rotation radius different from that of the drum 42, and includes a support cylinder portion 61 that fits the spindle shaft 11 therein, an annular outer peripheral wall portion 62 that contacts the drum 42, A support cylinder portion 61 and a disc-shaped upper surface portion 63 that connects the upper end portions of the outer peripheral wall portion 62 are provided. Further, the dummy tire 60 has a roundness higher than that of the tire T and has a rigidity capable of maintaining the roundness even when a load from the drum 42 is received in the radial direction.

In the present embodiment, the dummy tire 60 is made of steel, but it can also be made of other metals such as aluminum or resin such as hard plastic. The roundness is preferably 10 μm or more, and most preferably a perfect circle. Further, the dummy tire 60 is formed as a gap between the support cylinder portion 61 and the outer peripheral wall portion 62, and thus has a mass comparable to that of the tire T by reducing the weight. Moreover, it is also preferable to arrange ribs extending from the support cylinder part 61 to the outer peripheral wall part 62 at a plurality of positions.
In the present embodiment, the diameter ratio between the dummy tire 60 and the drum 42 is different (for example, 11:17). This prevents the rotation period of the drum 42 and the dummy tire 60 from being the same or close to each other and sets the multiple components of these rotation speeds to be less than the analysis target multiple component and not the least common multiple relationship. ing. Thereby, when extracting only the rotational speed component of the dummy tire 60 and its harmonic component, the fluctuating load generated due to non-uniformity such as the roundness of the drum 42 is removed.

Next, the substitute road surface body 41 of the drum 42 is pressed against the dummy tire 60 to apply a load from the drum 42 to the dummy tire 60.
Then, the tire T is rotated by rotating the drum 42 in a state where the distance between the spindle shaft 11 and the drum shaft 43 is kept constant, and the generated variable load is measured by the processing control device. Thereafter, the test is terminated, and the inspection of the tire testing machine 1 is completed by judging the accuracy of the tire testing machine 1 from the obtained measurement value.
Here, since the dummy tire 60 rotates while maintaining the roundness, theoretically, a fluctuating load caused by the dummy tire 60 does not occur during the test, and thus the rotational speed of the dummy tire 60 is increased. On the component, a fluctuating load resulting from the tire testing machine 1 is measured. As a result, the fluctuating load caused by the tire testing machine 1 is actually grasped.

Since the accuracy of the tire testing machine 1 is indicated by the fluctuating load in this way, according to the accuracy inspection method of the present embodiment, the accuracy of the tire testing machine 1 is grasped by performing the test with the dummy tire 60 at least once. As a result, the labor of replacing the tire T, which has been borne by the operator in the conventional accuracy inspection method, is greatly reduced, and the time required for the test and the amount of data can be reduced. Therefore, the accuracy of the tire testing machine 1 can be inspected extremely efficiently. Of course, the accuracy of the tire testing machine 1 may be comprehensively inspected and judged by performing the above test a plurality of times.
[Second Embodiment]
In the present embodiment, the configuration for inspecting the accuracy of the tire testing machine 1 is different from that in the first embodiment, but the configuration of the tire testing machine 1 and the configuration of the dummy tire 60 are the same as those in the first embodiment. Therefore, these configurations are denoted by the same reference numerals as those in the first embodiment and description thereof is omitted.

The intended place of this embodiment is as follows.
The fluctuating load measured by bringing the dummy tire 60 into contact with the drum 42 includes the fluctuating load caused by bringing the dummy tire 60 into direct contact with the drum 42 in addition to the fluctuating load caused by the tire testing machine 1. Will be measured. The contact variation load corresponds to a value obtained by multiplying the radius variation of the dummy tire 60 by the rigidity between the contact portions of the dummy tire 60 and the drum 42, and should be ignored in the accuracy inspection of the tire testing machine 1 itself. . The contact rigidity is obtained based on the rigidity of both the drum 42 and the dummy tire 60 that contacts the drum 42.

However, since the drum 42 is generally made of a hard material such as metal, the contact rigidity between the drum 42 and the dummy tire 60 that contacts the drum 42 is the tire T that contacts the drum 42 and the drum 42. Considerably larger than the contact rigidity. For this reason, if the radial fluctuations of the dummy tire 60 and the tire T are the same, the fluctuation load generated between the dummy tire 60 and the drum 42 is significantly larger than the fluctuation load generated between the tire T and the drum 42. Become.
In addition, it is actually very difficult to manufacture a dummy tire 60 that is completely circular. Even when such a dummy tire is manufactured, the dummy tire 60 is slightly misaligned with the spindle shaft 11. It is also possible that it will be attached in the state of being.

In such a case, even when the test is performed as in the first embodiment, it is inevitable that the dummy tire 60 has a radius variation. For this reason, when the dummy tire 60 is brought into contact with the drum 42 and the fluctuating load is measured, the radial fluctuation of the dummy tire 60 becomes large and the fluctuating load becomes large. Thus, the present embodiment has been considered.
In this embodiment, as shown in FIG. 3, when the test of the tire testing machine 1 is performed, the dummy tire 60 and the drum 42 are rotated at least at a different period from the dummy tire 60 and contact with the dummy tire 60. A buffer body 70 having a part lower in rigidity than the dummy tire 60 is interposed.

The buffer body 70 is formed by forming an elastic resin in an annular shape, and is wound around the drum 42. As a result, the buffer body 70 is interposed between the drum 42 and the dummy tire 60 and rotates at a different period from the dummy tire 60.
According to the present embodiment, the buffer 70 is interposed between the drum 42 and the dummy tire 60, so that the contact rigidity that has been caused by bringing the dummy tire 60 into direct contact with the drum 42 is reduced. The load generated by the 60 radius variation is reduced. As a result, the generation of a fluctuating load caused by bringing the dummy tire 60 into direct contact with the drum 42 is suppressed.

In addition, the fluctuating load due to the non-uniformity (for example, roundness error) of the buffer body 70 appears on the rotation speed component of the drum 42, and the above-mentioned on the rotation speed component of the dummy tire 60 The variable load resulting from the tire testing machine 1 appears as in the test of the first embodiment. For this reason, the tire testing machine 1 can be inspected with high accuracy even in a state where the buffer body 70 is interposed.
In the present embodiment, the load cell 55 may be arranged in the drum device 3 to measure the fluctuating load on the drum shaft 43 side.
[Third Embodiment]
In the present embodiment, the configuration of the shock absorber 70 is different from that of the second embodiment, but the configuration of the tire testing machine 1 and the configuration of the dummy tire 60 are the same as those of the second embodiment, that is, the first embodiment. Therefore, only the configuration of the buffer body 70 will be described, and other configurations will be denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted.

As shown in FIG. 4, the buffer body 70 of the present embodiment is pivotally supported by a rotating shaft 71 parallel to the spindle shaft 11 and is formed in a rotating body shape around the rotating shaft 71 with a rotation radius different from that of the dummy tire 60. Has been. As a result, the shock absorber 70 rotates at a different period from that of the dummy tire 60, and the fluctuating load caused by the shock absorber 70 is different from that of the dummy tire 60 and the drum 42 as indicated by D in FIG. Appear on different frequency components, and there is no possibility that the fluctuating load will hinder measurement of fluctuating load caused by the tire testing machine.
In addition, it is preferable that the double component of the rotational speed of the dummy tire 60, the buffer body 70, and the drum 72 is less than the analysis target multiple component and does not have the least common multiple relationship. In this embodiment, these ratios are set to 11: 9. : 17 is set.

The buffer body 70 is formed by fitting a metal inner fitting member 73 into an elastic resin roll member 72 having a lower rigidity than the dummy tire 60. As a result, the thickness of the portion that contacts the dummy tire 60 and has a lower rigidity than the dummy tire 60 is sufficiently ensured. It is preferable to substitute the tire T as the buffer body 70.
The axis of the rotary shaft 71 extends in a vertical direction on a plane including the axis of the spindle shaft 11 and the axis of the drum shaft 43, and a buffer body 70 is pivotally supported at the lower end of the rotary shaft 71. An upper end portion is pivotally supported around a swing shaft 74 perpendicular to the plane. Thereby, the buffer body 70 can swing around the swing shaft 74.

The present embodiment has the above configuration.
When testing the tire testing machine 1 according to the present embodiment, first, the shock absorber 70 is disposed on the dummy tire 60 and the drum 42 and is brought into contact with the dummy tire 60 and the drum 42.
In this state, a load is applied from the drum 42 to the dummy tire 60, and the dummy tire 60 is rotated by rotating the drum 42 while maintaining a constant distance between the spindle shaft 11 and the drum shaft 43. The variable load generated when the dummy tire 60 is rotated is measured by the measuring device 52.

  By the way, in the inspection method according to the present invention, the drum 42 is rotated with a very large load (for example, 500 kg) applied from the drum 42 toward the dummy tire 60. For this reason, when the test as in the second embodiment is performed, for example, when the low-rigidity shock absorber 70 is employed, the shock absorber 70 may be easily broken by continuously receiving the high load as described above. is there. On the other hand, when the shock absorber 70 is adopted by a highly rigid material having resistance against the high load, the shock absorber 70 is difficult to bend, and the work of winding the shock absorber 70 around the drum 42 becomes extremely difficult.

On the other hand, according to this embodiment, since the buffer body 70 that can be rotated independently is installed between the dummy tire 60 and the drum 42, the buffer body 70 can be installed and replaced very easily. be able to.
In addition, a portion that contacts the dummy tire 60 and has a lower contact rigidity than the dummy tire 60 is formed sufficiently thick in the radial direction of the shock absorber 70, thereby further reducing the contact rigidity between the dummy tire 60 and the shock absorber 70. The Rukoto.
Further, according to the present embodiment, the dummy tire 60 and the drum 42 rotate while the drum 42 is slightly inclined with respect to the dummy tire 60 due to a slight parallelism error between the spindle shaft 11 and the drum shaft 43. In this case, the shock absorber 70 can swing around the swing shaft 74 to follow the abnormal rotation of the drum 42. As a result, the radius fluctuation caused by the slight parallelism error between the spindle shaft 11 and the drum shaft 43 is satisfactorily absorbed by the buffer body 70, and the generation of the fluctuating load is suppressed, so that a more accurate inspection is performed. Will be.

In the present embodiment, the load cell 55 may be arranged in the drum device 3 to measure the fluctuating load on the drum shaft 43 side. In this case, it is necessary to apply driving to the tire T.
[Fourth Embodiment]
In the present embodiment, the configuration of the shock absorber 70 is different from that of the second embodiment, but the configuration of the tire testing machine 1 and the configuration of the dummy tire 60 are the same as those of the second embodiment, that is, the first embodiment. Therefore, only the configuration of the buffer body 70 will be described, and other configurations will be denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted.

As shown in FIG. 5, the buffer body 70 of the present embodiment includes a roll 75 a pivotally supported on a rotation shaft 71 a parallel to the spindle shaft 11 and an elastic support device 75 that supports the roll 75 a. The roll 75a is formed in the shape of a rotating body having a diameter different from that of the dummy tire 60 around the rotation shaft 71a, and can thereby be rotated at a different period from the dummy tire 60.
The axis of the rotating shaft 71 a is located on a plane including the axis of the spindle shaft 11 and the axis of the drum 42.
The elastic support device 75 includes a cylinder tube 76 that contacts the drum 42 in a stationary state, a piston rod 77 that is housed in the cylinder tube 76 and supports both ends of the rotating shaft 71a of the roll 75a, and a base end of the piston rod 77. And a pump 78 capable of pumping / discharging air in a room R formed by the cylinder tube 76. When the room R is filled with air, the cylinder tube 76 and the piston rod 77 function as an air cylinder. By applying or removing an external force that pushes the piston rod 77 into the cylinder tube 76, the air cylinder contracts or extends. It will be.

In the present embodiment, a rotating device 80 that applies a rotational force to the dummy tire 60 is provided. The rotating device 80 includes a tire T-shaped rotating member 81 that rotates around a rotating shaft 71 parallel to the spindle shaft 11 and contacts the dummy tire 60, and a rotating motor 82 that applies a rotating force to the rotating member 81. I have. The rotating member 81 is in contact with the dummy tire 60 to the extent that it touches (skim touch), thereby preventing an excessive load from being applied to the dummy tire 60 from the rotating member 81 as much as possible.
In this embodiment, since the drum 42 is not operated as will be described later, the load cell 55 is arranged in the tire rolling device 2 to measure the fluctuating load on the spindle shaft 11 side, and the load cell 55 on the drum shaft 43 side. Is not configured to deploy.

The present embodiment has the above configuration.
In order to perform the test according to the present embodiment, first, the roll 75a is brought into contact with the tire and the cylinder tube 76 is brought into contact with the drum 42, and the room 78 is filled with air by the pump 78. Next, by adjusting the distance between the spindle shaft 11 and the drum shaft 43, a load from the drum 42 is applied to the dummy tire 60 via the buffer body 70. Then, the dummy tire 60 is rotated by operating the rotating device 80 in a state where the distance between the spindle shaft 11 and the drum shaft 43 is kept constant. Then, the generated variable load is measured by the measuring device 52.

According to the present embodiment, the contact rigidity caused by bringing the roll 75a into direct contact with the dummy tire 60 is reduced by the elastic action of the air cylinder of the buffer body 70, and the load generated by the radius variation of the dummy tire 60 is small. Become. As a result, the occurrence of a fluctuating load (contact fluctuating load) due to direct contact of the dummy tire 60 with the roll 75a is suppressed.
[Fifth Embodiment]
In the present embodiment, the configuration of the buffer body 70, in particular, the elastic support device 75 is different from that of the fourth embodiment, but the other configurations are the same as those of the fourth embodiment, that is, the first embodiment. Only the configuration of the support device 75 will be described, and other configurations will be denoted by the same reference numerals as those of the first embodiment, and description thereof will be omitted.

As shown in FIG. 6, the elastic support device 75 of this embodiment includes a support member 85 that supports both ends of the rotating shaft 71 a of the roll 75 a, and an air spring 85 a that is disposed between the end of the support member 85 and the drum 42. A rotating device 86 that applies a rotational force to the rotating shaft 71a, and a moving device 87 that moves the rotating device 86 and the roll 75a between the drum shaft 43 and the spindle shaft 11.
According to the elastic support device 75, the roll 75 a is supported by the air spring 85 a through the support member 85. Thus, the roll 75a can move in a direction perpendicular to the axis. The movement of the roll 75a is guided by the moving device 87.

In the present embodiment, since the drum 42 is not operated, the load cell 55 is provided in the tire rolling device 2 to measure the fluctuating load on the spindle shaft 11 side, and the load cell 55 is provided on the drum shaft 43 side. Not.
The present embodiment has the above configuration.
In order to perform a test according to the present embodiment, first, the interval between the spindle shaft 11 and the drum shaft 43 is adjusted in a state where the air spring 85a of the elastic support device is in contact with the drum 42 and the roll 75a is in contact with the dummy tire 60. Then, a load from the drum 42 is applied to the dummy tire 60 via the buffer body 70. Then, the tire T is rotated by operating the rotating device 86 in a state where the distance between the spindle shaft 11 and the drum shaft 43 is kept constant. Then, the generated variable load is measured by the measuring device 52.

Also in the present embodiment, the contact rigidity generated when the roll 75a is brought into direct contact with the dummy tire 60 is reduced by the elastic action of the air spring 85a of the shock absorber 70. As a result, the dummy tire 60 is directly contacted with the roll 75a. Generation | occurrence | production of the fluctuation | variation load (contact fluctuation | variation load) by making it contact will be suppressed.
[Sixth Embodiment]
In the present embodiment, the configuration of the dummy tire 60 is different from that of the second embodiment, but the other configurations are the same. Therefore, only the configuration of the dummy tire 60 will be described, and the other configurations are the same as those of the second embodiment. The same reference numerals are given and description thereof is omitted.

As shown in FIG. 7, the dummy tire 60 of the present embodiment has a weight attachment portion 65 to which a weight 67 can be attached to the upper surface portion 63 at one or a plurality of positions that are radially outward from the rotation center supported by the spindle shaft 11. It has.
The weight attaching portion 65 is formed by opening a plurality of (three in the present embodiment) screw holes 66 in the radial direction of the dummy tire 60. It is preferable that the intervals between the adjacent screw holes 66 are equal to each other. Moreover, it is preferable that the space | interval of the adjacent weight attachment part 65 is also equal intervals, and the eight weight attachment parts 65 are provided in the upper surface part 63 in this embodiment.

As shown in FIG. 8, the weight 67 is attached to the dummy tire 60 by screwing the weight 67 into any one of the screw holes 66 of the weight attaching portion 65 from above the upper surface portion 63. By attaching the weight 67 in this manner, the center of gravity of the dummy tire 60 is shifted from the center of rotation, and thereby the dummy tire 60 is in an eccentric unbalanced state. By rotating the dummy tire 60 in this state, a fluctuating load due to unbalance (hereinafter referred to as unbalance force) acts on the dummy tire 60. When the mass of the weight 67 is m, the distance from the rotation center of the dummy tire 60 to the mounting position of the weight 67 is r, and the rotational angular velocity of the dummy tire 60 is ω, the unbalance force f is f = mrω ² .

Here, the unbalance force acts on the load cell 55 that supports the spindle shaft 11 and also acts on the shock absorber 70 that contacts the dummy tire 60. Since the rigidity of the load cell 55 is significantly larger than the rigidity of the buffer body 70, almost all unbalance forces act on the load cell 55.
The present embodiment has the above configuration.
In order to perform a test according to the present embodiment, first, the weight 67 is attached to the weight attaching portion 65 of the dummy tire 60. Then, a load is applied to the dummy tire 60 by pressing the drum 42 against the dummy tire 60 via the buffer body 70. Next, the tire T is rotated by operating the driving device 45 in a state where the distance between the spindle shaft 11 and the drum shaft 43 is kept constant. Then, the generated variable load is measured by the measuring device 52.

According to the present embodiment, it is possible to perform a test of the tire testing machine 1 that compares the fluctuating load generated by the rotation of the dummy tire 60 with the unbalance force. Further, since the position of the weight 67 can be changed as necessary, a plurality of conditions can be set with the same weight 67 at the same rotation speed.
Further, since the position of the weight 67 is determined by the weight attaching portion 65, it can be made known by calculating in advance the unbalance force of the dummy tire 60 in which the center of gravity is decentered by the weight 67.

Further, by performing a plurality of experiments by changing not only the position of the weight 67 but also the rotational speed ω of the dummy tire and the mass m of the weight 67, the measurement accuracy of the measuring device 52 such as the load cell 55 is more detailed. Can be inspected.
In this embodiment, it is also possible to shift the center of gravity of the dummy tire 60 from the center of rotation by attaching weights 67 to all the screw holes 66 and removing a plurality of weights 67 therein. Moreover, the dummy tire 60 of this embodiment can be employed not only in the second embodiment but also in the third to fifth embodiments.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, when the drum shaft 43 and the spindle shaft 11 are horizontal and the drum 42 and the dummy tire 60 are vertically rotated, the same effects as in the present embodiment can be obtained.

It is side part sectional drawing which shows 1st Embodiment of this invention. (A) And (b) is a figure which shows the result of having frequency-analyzed the fluctuating load measured by a measuring device. It is side part sectional drawing which shows 2nd Embodiment of this invention. It is side part sectional drawing which shows 3rd Embodiment of this invention. It is side part sectional drawing which shows 4th Embodiment of this invention. It is side part sectional drawing which shows 5th Embodiment of this invention. It is a top view which shows the dummy tire of 6th Embodiment of this invention. It is side part sectional drawing which shows the state which has arrange | positioned the dummy tire to the tire rolling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tire testing machine 2 Tire rolling apparatus 3 Drum apparatus 4 Processing control apparatus 11 Spindle shaft 42 Drum 45 Drive apparatus 52 Measuring apparatus 53 Measuring instrument 54 Calculation means 60 Dummy tire 65 Weight attachment part 67 Weight 70 Buffer body 71 Rotating shaft 71a Rotation Shaft 75 Elastic support device 75a Roll T Tire

Claims (8)

A spindle shaft on which a tire can be mounted, a drum that rotates around a drum shaft parallel to the spindle shaft and that is pressed against the tire and applies a load to the tire; and a drum that is rotated against the tire In the method of checking the accuracy of a tire testing machine equipped with a measuring device that measures the resulting variable load,
Instead of the tire, a dummy tire having a rotation radius different from that of the drum and a roundness higher than that of the tire and having rigidity capable of maintaining the roundness even when the load is received in a radial direction. Is mounted on the spindle shaft, and the variable load generated by rotating the dummy tire with a load applied from the drum is measured by the measuring device.   2. The accuracy of the tire testing machine according to claim 1, wherein the dummy tire is rotated after interposing a buffer body having rigidity lower than that of the dummy tire between the dummy tire and the drum. Inspection method.   3. The tire testing machine accuracy inspection method according to claim 2, wherein the shock absorber is wound around the drum and rotated together with the drum. The shock absorber is pivotally supported by a rotating shaft parallel to the spindle shaft, and has a rotating radius different from that of the dummy tire around the rotating shaft, and is formed in a rotating body shape that rotates at a different period from the dummy tire. And
3. The method of checking accuracy of a tire testing machine according to claim 2, wherein the shock absorber is rotated together with the dummy tire and the drum while being sandwiched between the dummy tire and the drum. The measuring device measures the fluctuating load on the spindle shaft,
The dummy tire includes a weight attaching portion capable of attaching a weight at one or a plurality of positions in a radially outward direction from a rotation center supported by the spindle shaft.
The load is attached to or removed from the weight attaching portion, the dummy tire is rotated in a state where the center of gravity of the dummy tire is shifted from the center of rotation, and the variable load is measured on the spindle side by the measuring device. The method for inspecting the accuracy of the tire testing machine according to claim 4. The measuring device measures the fluctuating load on the spindle shaft side,
The shock absorber includes a roll that rotates around a rotation axis parallel to the spindle shaft in contact with the dummy tire, and an elastic support device that elastically presses and supports the roll against the dummy tire,
3. The tire testing machine according to claim 2, wherein the dummy tire is rotated in a state where the roll is in contact with the dummy tire from the drum side, and the variable load is measured on the spindle side by the measuring device. Accuracy inspection method.   The accuracy inspection method for a tire testing machine according to claim 6, wherein the roll is supported so as to be movable in an axial direction of the rotating shaft. The dummy tire includes a weight attaching portion capable of attaching a weight at one or a plurality of positions in a radially outward direction from a rotation center supported by the spindle shaft.
The method of checking the accuracy of a tire testing machine according to claim 6 or 7, wherein the dummy tire is rotated in a state where the weight is attached to or removed from the weight attaching portion and the center of gravity of the dummy tire is shifted from the center of rotation. .

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