JP5642040B2 - Tire uniformity test apparatus and tire uniformity test method - Google Patents

Description

  The present invention relates to a test technique for a tire uniformity machine, and more particularly to a test technique for a tire uniformity that can improve the measurement accuracy of radial force variation (RFV).

Conventionally, tire tests (uniformity inspection) have been performed on tires that have risen in product quality to determine quality by measuring uniformity (uniformity) and the like. For example, in the case of measuring uniformity for tires for passenger cars, this tire test is generally performed by the following procedure using a test apparatus disclosed in Patent Document 1.
That is, the tire test apparatus of Patent Document 1 includes a pneumatic circuit that adjusts and supplies compressed air supplied from a factory air source to a tire seated on a rim, and inflates the tire to a test pressure. The tire test will be performed later.

  When a tire test is performed with this tire testing apparatus, the tire flowing from the upstream of the inspection line is sandwiched between rims divided vertically. Next, the tire is inflated and fixed to the rim in a short time using a bead seat system pipe which is one pipe branched into two systems in the middle of the pneumatic circuit. The drum is pressed against the tire held at the test pressure with compressed air from the test system, which is another pipe, and the tire is measured for uniformity. Then, the tire is reversed, and the tire uniformity at the time of reverse rotation is also measured.

  By the way, in the tire uniformity measuring method as described above, when the load drum is reversely rotated from the state in which the load drum is rotating in a certain direction, the load drum is instantaneously stopped. If the tire is stopped in a state where a constant pressure is applied to the tire, the tire dent caused by the pressure of the load drum will later become a residual dent (see FIG. 5). This is due to the viscoelastic properties of the tire rubber material. It is clarified in Patent Document 1 that it takes time until the residual dent is restored to the original state, and measuring the uniformity in this state greatly affects the measurement accuracy. There is a problem in that it takes time to wait until the tires are restored and the waveform of the uniformity is stabilized, which takes time.

  Therefore, Patent Document 2 proposes a method for reducing the pressure acting on the tire when the tire is stopped by retreating the contact surface of the load drum from the tire tread surface when the tire reverses as one of the solutions to the above-described problem. Has been.

Japanese Patent Publication No. 6-95057 JP-A-2-2233843

  By the way, when measuring the tire uniformity at the time of tire reversal using the tire testing device disclosed in Patent Document 2, if the load drum is retracted from the tire, the tire dent caused by the pressure by the load drum disappears. The volume in the tire (internal volume) increases. As a result, the pressure in the tire decreases. By the action of the pressure regulating valve, compressed air is sent into the tire to make the tire internal pressure the test pressure. After the end of the reverse rotation, the load drum is advanced to the same position as in the forward rotation to apply a load. At this time, the tire is depressed again due to the pressure of the load drum, and the volume in the tire decreases. The tire internal pressure increases momentarily due to the decrease in volume. It takes time for the tire internal pressure to be stabilized at a predetermined test pressure by the pressure regulating valve. When the test pressure of the tire internal pressure is not stable, the uniformity waveform is not stable, and it has been clarified that simply the backward and forward movement of the load drum does not lead to shortening of the measurement time.

  The present invention has been made in view of the above-described problems. In tire uniformity measurement, an accurate tire uniformity, particularly a change in force in the tire radial direction, is obtained immediately after switching from the normal rotation to the reverse rotation. It is an object of the present invention to provide a tire uniformity test apparatus and a tire uniformity test method that can accurately determine (RFV).

In order to achieve the object, the present invention takes the following technical means.
That is, the tire uniformity testing apparatus of the present invention supports a drum rotatably, and allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and compressed air is applied to the tire. In the tire uniformity testing apparatus including the pneumatic circuit to supply, when the rotation of the tire is reversed, the drum mechanism retracts the drum while maintaining a contact state with the tire, and rotates the tire in one direction. It is configured so that the load can be applied to the tire by advancing the drum and then moving the drum forward, and the pneumatic circuit reverses the rotation of the tire from one direction rotation to the other direction rotation. When the operation is performed, the compressed air having a volume substantially equal to the increase / decrease amount of the volume inside the tire is taken in / out along with the backward / forward movement of the drum. The volume adjustment mechanism that is characterized in that is provided.

Preferably, the pneumatic circuit includes an air supply source that supplies compressed air, a pressure adjustment valve that adjusts the pressure of the compressed air sent from the air supply source to a test air pressure and that can be supplied to the tire; The volume adjustment mechanism may be provided between the tire and the pressure adjustment valve.
Preferably, the volume adjusting mechanism includes a cylinder that communicates with a pneumatic circuit and stores compressed air inside the tire, a piston that moves within the cylinder, and a servo motor that moves the piston. Good.

Preferably, the volume adjusting mechanism may be configured to adjust the volume of compressed air inside the tire by changing the direction and / or speed of movement of the servo motor.
On the other hand, in the tire uniformity measuring method of the present invention, a drum mechanism that rotatably supports a drum and that allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and compressed air is applied to the tire. In a tire uniformity measurement method using a tire uniformity test apparatus provided with a pneumatic circuit to supply, when the rotation of the tire is reversed, the drum mechanism is moved backward while maintaining a contact state with the tire, The rotation of the tire is switched from one direction rotation to the other direction rotation, and then the drum is advanced so that a load can be applied to the tire, and the rotation of the tire is changed from one direction rotation to the other direction rotation. When the reversing operation is performed, the pressure of the volume substantially coincides with the increase / decrease amount of the volume inside the tire in conjunction with the backward and forward movement of the drum. So as to out the air, and measuring tire uniformity.
The most preferable form of the tire uniformity testing apparatus according to the present invention is a drum mechanism that rotatably supports a drum and that allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and the tire. In the tire uniformity test apparatus having a pneumatic circuit for supplying compressed air to the drum, the drum mechanism retracts the drum while maintaining the contact state with the tire when reversing the rotation of the tire, The rotation is switched from one-direction rotation to the other-direction rotation, and then the drum is advanced to apply a load to the tire. The pneumatic circuit includes an air supply source for supplying compressed air, In addition, the pressure of the compressed air sent from the air supply source is adjusted to the test air pressure, and the pressure can be supplied to the tire. In addition, when the rotation of the tire is reversed from one direction rotation to the other direction rotation, the volume of compressed air that substantially matches the increase / decrease amount of the volume inside the tire is taken in and out along with the backward and forward movement of the drum. A volume adjustment mechanism is provided, and the volume adjustment mechanism is provided between the tire and the pressure adjustment valve, and makes the pressure inside the tire substantially constant within a range in which the pressure adjustment valve does not operate. It is comprised as follows.
The most preferred embodiment of the tire uniformity test method according to the present invention is a drum mechanism that rotatably supports a drum and that allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and the tire. In a tire uniformity measurement method using a tire uniformity test apparatus having a pneumatic circuit for supplying compressed air to the drum, the drum mechanism maintains the drum in contact with the tire when the rotation of the tire is reversed. The tire rotates backward and switches the rotation of the tire from one direction to the other. Then, the drum is advanced so that a load can be applied to the tire. The rotation of the tire is rotated in one direction. When the reversing operation from the rotation to the other direction is performed, the pneumatic circuit is provided in conjunction with the backward movement of the drum. In the manner as the pressure regulating valve and out the compressed air volume to be substantially equal to the amount of increase or decrease of the volume inside the tire in a range that does not work, and measuring the uniformity of the tire.

  According to the tire uniformity test technique of the present invention, in tire uniformity measurement, accurate tire uniformity, particularly force fluctuation (RFV) in the tire radial direction is accurately obtained immediately after switching from normal rotation to reverse rotation. It can be obtained.

1 is a schematic view of a tire uniformity test apparatus according to the present invention. It is a figure which shows a pneumatic circuit. It is a figure which shows the operation | movement pattern of a tire uniformity testing apparatus, and the measured uniformity waveform. It is a figure which shows the pneumatic circuit of another type. It is a figure which shows the relationship between a load drum and a tire residual dent (conventional example).

A tire uniformity test apparatus 1 and a tire uniformity test method according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the tire uniformity test apparatus 1 evaluates the tire uniformity characteristics of the tire T that has risen as a product, particularly, the radial force variation (RFV) in the tire T radial direction as a product inspection. is there.

  Specifically, the tire uniformity testing device 1 is rotatable around a vertical axis through a cylindrical frame main body 2 arranged so that its axis is directed vertically, and a bearing portion in the frame main body 2. And a spindle shaft 3 attached in this manner. The spindle shaft 3 protrudes upward from the upper end of the frame body 2, and a pair of upper and lower rims 4 for fixing the tire T to the upward projecting portion of the spindle shaft 3 are provided. Further, on the side of the tire T fixed by the rim 4, a drum 5 (load drum) having a simulated road surface 6a formed on the outer peripheral surface thereof is provided. The drum 5 is provided in the drum mechanism 6.

In the description of the present specification, the top and bottom of the paper surface of FIG. 1 are the top and bottom when the tire uniformity test apparatus 1 is described.
The drum mechanism 6 of the present embodiment is configured to support the drum 5 so as to be able to drive and rotate about the vertical axis, and to move horizontally to contact the simulated road surface 6a with the tire T. When the drum mechanism 6 reverses the rotation of the tire T, the drum 5 is moved backward while maintaining the contact state with the tire T, and the rotation of the tire T is rotated from one direction (forward rotation) to the other direction (reverse rotation). Then, the drum 5 is moved forward to apply a load to the tire T.

As shown in FIG. 1, when performing a tire test, it is necessary to adjust the tire T to a predetermined air pressure. Therefore, the tire uniformity test apparatus 1 supplies the compressed air generated by the air supply source 9 to the inside of the tire T, or discharges the compressed air from the inside of the tire T to the outside such as the atmosphere, so that the air pressure in the tire T is exhausted. A pneumatic circuit 7 for adjusting the pressure is provided.
Specifically, as shown in FIG. 2, the pneumatic circuit 7 includes two supply piping systems. One is the pipe of the bead seat system 10 for inflating the tire T in a short time and mounting the tire T on the rim 4, and the other is the pipe of the test system 11 used when testing the tire T.

  The compressed air circulated through the bead sheet system 10 is adjusted to an air pressure (bead pressure) of about 0.4 MPa, and the compressed air circulated through the test system 11 is about 0.2 MPa lower than the bead sheet system 10. The air pressure (test pressure) is adjusted. In the bead seat system 10 and the test system 11, the air flow path branches in the middle from the air supply source 9 to the tire T, and after being adjusted to the respective air pressures, the bead seat system 10 and the test system 11 merge again into one pipe. ing. The pipe of the bead seat system 10 and the pipe of the test system 11 can be switched using a switching valve 15.

  In the piping path of the test system 11, the air supply source 9 and the pressure adjustment valve (hereinafter also referred to as the test pressure adjustment valve 13) are sequentially arranged from the upstream side (side near the air supply source 9) to the downstream side. A supply / exhaust valve 14, a switching valve 15, a shutoff valve 16, and a pressure detector 17 are provided. Further, the piping path of the bead seat system 10 branches from the piping of the test system 11 downstream of the air supply source 9 and is adjusted to bead pressure by another pressure adjustment valve (hereinafter, also referred to as a bead pressure adjustment valve 12). After the adjustment, the switching valve 15 joins the pipe of the test system 11.

  The air supply source 9 is connected to an air compressor or factory air supply source (not shown), and generates compressed air having a pressure equal to or higher than the air pressure when the tire T is inflated through the bead seat system 10. An air filter 18 that collects dust flowing in from the air supply source 9 is provided on the downstream side, and the pressure of compressed air generated in the air supply source 9 is checked on the downstream side of the air filter 18. A pressure gauge 19 is provided.

  The test pressure adjusting valve 13 provided in the test system 11 and the beat pressure adjusting valve 12 provided in the beat seat system are both pressure regulators that adjust the compressed air sent from the air supply source 9 to a predetermined pressure. . The pressure regulating valve of the present embodiment uses a pressure reducing valve controlled by an internal pilot type having a relief function, and the pressure of the compressed air generated by the air supply source 9 is set to a beat pressure (for example, 0.4 MPa) or It can be adjusted by reducing the pressure to a test pressure (for example, 0.2 MPa).

The supply / discharge valve 14 is a directional control valve (a directional control valve in which pilot pressure is controlled by an electromagnetic method) provided on the downstream side of the test pressure adjusting valve 13 provided in the test system 11. The air supply to the tire T before the start of the tire test and the exhaust (release to the atmosphere) from the tire T after the end of the tire test are controlled.
The switching valve 15 switches the flow path of the compressed air between the test system 11 side and the bead seat system 10 side, and is used to switch the air pressure in the tire T between the bead pressure and the test pressure. The switching valve 15 is composed of a directional control valve whose pilot pressure is controlled by an electromagnetic type.

The shut-off valve 16 is a directional control valve provided on the downstream side of the switching valve 15. In the pipe that cuts the flow path of the compressed air by switching the valve and reaches the inside of the tire T on the downstream side of the shut-off valve 16. Compressed air can be contained.
The pressure detection unit 17 includes an air pressure sensor provided on the downstream side of the supply / discharge valve 14 and detects the air pressure acting in the tire T.

  By the way, when the drum mechanism 6 described above reverses the rotation of the tire T, the drum 5 is moved backward while maintaining the contact state with the tire T, and the rotation of the tire T is switched from normal rotation to reverse rotation. The drum 5 is moved forward to apply a load to the tire T. When the drum 5 is moved forward and backward in this manner, it is possible to prevent the “remaining dent from being generated on the surface of the tire T” disclosed in Patent Document 1, but from the drum 5 when the tire T rotation direction is switched. The load applied to the tire T changes and the volume (internal volume) in the tire T also varies.

  For example, when the drum 5 is retracted from the tire T before the rotation direction is reversed, the internal volume in the tire T increases and the pressure in the tire T decreases. Then, compressed air is fed into the tire T by the function of the test pressure adjusting valve 13 so as to make the tire T internal pressure the test pressure. Thereafter, when the drum 5 is advanced to the same position as that during forward rotation and a load is applied, the internal volume in the tire T decreases and the internal pressure in the tire T increases instantaneously.

In other words, when the internal pressure of the tire T fluctuates instantaneously with the reverse rotation of the rotation direction, an extra pressure adjustment is performed by the test pressure adjusting valve 13 to stabilize the fluctuating tire T internal pressure, and this internal pressure fluctuation stabilization During this time, the accuracy of the tire uniformity test cannot be guaranteed.
Therefore, the pneumatic circuit 7 of the tire uniformity testing apparatus 1 of the present invention has a volume that substantially matches the increase / decrease amount of the internal volume of the tire T in accordance with the backward and forward movement operation of the drum 5 when the reverse operation of the tire T is performed. A volume adjustment mechanism 20 for taking in and out compressed air is provided.

  If such a volume adjusting mechanism 20 is provided, it is possible to suppress the fluctuation of the volume inside the tire T in accordance with the backward and forward movement of the drum 5 and to make the pressure inside the tire T substantially constant. Become. As a result, the test pressure adjusting valve 13 does not operate, and it is possible to save useless time required to stabilize the tire T internal pressure, thereby improving the efficiency of the tire T uniformity test.

In other words, the volume adjustment mechanism 20 prevents the test pressure adjustment valve 13 from operating due to a change in the volume inside the tire T in conjunction with the backward and forward movement of the drum 5. The pressure inside the tire T is configured to be constant (substantially constant) within a range in which the valve 13 does not operate.
As shown in FIG. 2, the volume adjusting mechanism 20 is provided in the piping of the test system 11 of the pneumatic circuit 7, and is downstream of the test pressure adjusting valve 13 and further downstream of the shutoff valve 16 (shutoff). Between the valve 16 and the tire T).

  The volume adjustment mechanism 20 of the present embodiment includes a cylinder 22 and a piston 21 that moves in the cylinder 22. The cylinder 22 has a cylindrical shape whose inside is hollow, and one end thereof communicates with a pipe between the shutoff valve 16 and the pressure detection unit 17, and the other end is opened to the outside via a silencer 24. Yes. The piston 21 is inserted into the cylinder 22 and can move inside the cylinder 22. The volume of the compressed air supplied to the tire T can be adjusted by increasing or decreasing the volume of the compartment on the side communicating with the air flow path.

The piston 21 of the volume adjusting mechanism 20 has a piston 21 rod connected to the piston 21 connected to a servo motor 23 via a rack and pinion. By rotating the servo motor 23, the inside of the cylinder 22 is straightened. It can be moved.
The amount of movement of the piston 21 by the servo motor 23 is determined in advance by setting the size of the tire T and the values of the amount of backward advancement of the drum 5, and the volume change in the tire T is obtained based on the values. The amount is a value obtained by dividing the amount by the internal cross-sectional area of the cylinder 22. The moving speed of the piston 21 is set to a speed that is substantially the same as the backward movement of the drum 5.

Next, a procedure for measuring tire uniformity using the tire uniformity test apparatus 1 of the present invention will be described.
First, when uniformity measurement is performed, the tire T flowing from the upstream of the inspection line is sandwiched between the rims 4 and 4 that are divided vertically.
Then, the tire T is inflated in a short time using the piping of the bead seat system 10 of the pneumatic circuit 7. At this time, the compressed air generated by the air supply source 9 is adjusted to a bead pressure (for example, a high pressure of about 0.4 MPa) by a bead pressure adjusting valve 12 provided in the middle of the pipe of the bead seat system 10. The compressed air adjusted to the bead pressure is supplied to the tire T through the switching valve 15 and the shutoff valve 16, and the tire T instantaneously expands due to the air pressure in the tire T becoming the bead pressure. The part is firmly attached to the rim 4.

After the tire T is mounted on the rim 4, the air pressure in the tire T is switched to a test pressure (for example, 0.2 MPa) to prepare for the tire test.
A test pressure adjusting valve 13 is provided in the piping of the test system 11, and the test pressure adjusting valve 13 adjusts the compressed air generated by the air supply source 9 to the test pressure and the tire T that has been set to bead pressure. The compressed air inside can be opened to the outside and reduced to the test pressure. The compressed air adjusted to the test pressure by the test pressure adjusting valve 13 is supplied to the tire T through the supply / discharge valve 14, the switching valve 15, and the shutoff valve 16. The compressed air causes the air pressure in the tire T to be adjusted to the test pressure. When the air pressure in the tire T becomes the test pressure, it is detected by the pressure detector 17 and the shutoff valve 16 is operated to shut off the piping between the switching valve 15 and the tire T. Then, the piping on the downstream side of the shutoff valve 16 and the inside of the tire T are shut off from the upstream side, and the preparation for performing the tire test is completed.

Thereafter, the drum 5 is pressed against the tire T held at the test pressure to “forward-rotate”, and the repulsive force generated in the tire T is measured using a load detector (load cell) or the like, whereby the RFV waveform of the tire T is measured. Is measured.
After the measurement of the RFV waveform in the forward rotation is finished, the tire T is “reversely rotated” and the RFV waveform is measured.

  First, during the forward rotation of the tire (the final stage of the RFV waveform measurement in the forward rotation), the drum 5 starts to be retracted immediately before the tire rotational speed is changed, and at the same time the rotational speed is decreased, the drum 5 is further retracted. . As the drum 5 moves backward, the drum 5 load decreases. The amount of retraction of the drum 5 is preferably set so that the load of the drum 5 remains such that no slip occurs between the tire T and the drum 5. This is because the rotation of the drum 5 is transmitted from the motor-driven spindle shaft 3 to the drum 5 via the tire T. Therefore, if the contact pressure between the drum 5 and the tire T is small, the rotation of the drum 5 is reduced or accelerated. This is because the tire T may slip due to the inertial force.

  Thereafter, when the rotation speed of the tire T is 0, that is, when the rotation of the drum 5 is stopped, the position of the drum 5 is controlled so that the load of the drum 5 is minimized. At this drum 5 position, this time, the tire T starts to reverse, and when the tire T accelerates in the reverse direction, the drum 5 is gradually advanced, and at the timing when the tire T rotation speed reaches the predetermined test rotation speed, the drum 5 A predetermined test position is reached. Then, the tire T is rotated in the reverse direction, and the uniformity waveform in the reverse rotation is measured.

At the time of switching the reverse rotation of the tire T described above, the volume adjustment mechanism 20 provided in the tire uniformity test apparatus 1 is operated by the following method.
When the drum 5 is retracted from the tire T after completion of the forward rotation test, the volume adjustment mechanism 20 is used to substantially match the increase amount of the volume (internal volume) in the tire T that increases in accordance with the retraction of the drum 5. A volume of compressed air is fed into the tire T. Specifically, the servo motor 23 is rotated, the piston 21 is moved in the pushing direction, in other words, the direction in which the volume in the cylinder 22 is reduced, and a volume of compressed air that substantially matches the increase in volume in the tire T. Into the pipe. The compressed air thus sent into the pipe is sent into the tire T through the pipe and replenished into the tire T.

When the drum 5 is advanced after the tire T is reversed, compressed air that substantially matches the volume (internal volume) of the tire T that decreases as the drum 5 advances is extracted from the tire T.
Specifically, the servo motor 23 is rotated to move the piston 21 in the extraction direction, in other words, the direction in which the volume in the cylinder 22 is increased, so that the volume of compressed air substantially matches the volume decrease in the tire T. Is extracted from the piping of the test system 11.

3 (a) to 3 (g), when rotating the tire T from the normal rotation to the reverse rotation, the tire T rotation speed, the drum 5 position, the drum 5 load, the RFV waveform of the prior art, the RFV waveform of the present invention, The change of the tire T internal pressure is shown. The RFV waveforms in FIG. 3D and FIG. 3F are those measured by the uniformity measuring unit 8.
When the volume adjusting mechanism 20 is not provided, when the drum 5 is moved backward and forward when the tire T is reversely rotated, as shown in FIG. 3E, the tire T internal pressure once decreases and then the drum 5 is advanced (measured). The pressure in the tire T decreases substantially linearly before returning to a predetermined test pressure (3 to 5 seconds in measurement time). During this time, as shown in FIG. 3D, the RFV waveform also shifts up and down with a certain slope. Thus, it is difficult to obtain a correct RFV from an RFV waveform that is shifted and shifted, and an error is included in the obtained RFV.

On the other hand, when the volume adjusting mechanism 20 is used, if the drum 5 is moved backward and forward when the tire T is reversely rotated, as shown in FIG. During this time, as shown in FIG. 3 (f), the RFV waveform does not shift and the correct RFV can be obtained.
As described above, by using the volume adjusting mechanism 20 of the present invention, it is possible to maintain the tire T at the test pressure even immediately after the reverse rotation of the tire T, and always obtain an accurate uniformity waveform and uniformity measurement value. This can contribute to shortening the measurement time and thus improving productivity.

When the tire T is removed after the tire test is performed, the supply / discharge valve 14 is operated in a state where the pipe of the test system 11 is used, and the compressed air of the tire T and the volume adjusting mechanism 20 is released into the atmosphere. . By doing so, preparation for mounting the next tire T and return to the origin of the piston 21 of the volume adjusting mechanism 20 are performed.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.

  For example, the installation location of the volume adjustment mechanism 20 is not limited to the position shown in FIG. As shown in FIG. 4, a volume adjustment mechanism 20 is provided in a pipe downstream of the test pressure adjustment valve 13 and upstream of the shutoff valve 16 (between the test pressure adjustment valve 13 and the supply / discharge valve 14). Also good. In this case, if the shutoff valve 16 is in a communication state, the volume adjusting mechanism 20 can draw compressed air into and out of the tire T, and keeps the pressure inside the tire T substantially constant when the drum 5 moves backward and forward. be able to.

That is, as long as it is on the piping of the test system 11, the volume adjusting mechanism 20 can be installed at any position between the tire T mounted on the tire testing apparatus and the test pressure adjusting valve 13.
Further, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Tire uniformity test apparatus 2 Frame main body 3 Spindle shaft 4 Rim 5 Drum 6 Drum mechanism 6a Simulated road surface 7 Pneumatic circuit 8 Uniformity measurement part 9 Air supply source 10 Bead seat system 11 Test system 12 Bead pressure adjustment valve 13 Test pressure adjustment valve 14 Supply / exhaust valve 15 Switching valve 16 Shut-off valve 17 Pressure detector 18 Air filter 19 Pressure gauge 20 Volume adjustment mechanism 21 Piston 22 Cylinder 23 Servo motor 24 Silencer T Tire

Claims (4)

A tire uniformity test including a drum mechanism that rotatably supports a drum and that allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and a pneumatic circuit that supplies compressed air to the tire. In the device
When the rotation of the tire is reversed, the drum mechanism retracts the drum while maintaining a contact state with the tire, switches the rotation of the tire from one direction rotation to the other direction rotation, and then advances the drum. It is configured to be able to give the load load to the tire,
The pneumatic circuit includes an air supply source that supplies compressed air, a pressure adjustment valve that adjusts the pressure of the compressed air sent from the air supply source to a test air pressure, and that can be supplied to the tire; A volume adjusting mechanism for taking in and out compressed air having a volume substantially equal to the increase / decrease amount of the volume inside the tire in conjunction with the backward and forward movement of the drum when the rotation is reversed from one direction rotation to the other direction rotation. with et al is,
The volume adjusting mechanism is provided between the tire and the pressure adjusting valve, and is configured to make the pressure inside the tire substantially constant within a range in which the pressure adjusting valve does not operate. A tire uniformity testing device. The volume adjusting mechanism includes a cylinder that communicates with a pneumatic circuit and stores compressed air inside a tire, a piston that moves inside the cylinder, and a servo motor that moves the piston. The tire uniformity testing apparatus according to claim 1 . The tire according to claim 2 , wherein the volume adjusting mechanism is configured to adjust the volume of compressed air inside the tire by changing a direction and / or speed of movement of the servo motor. Uniformity test equipment. A tire uniformity test including a drum mechanism that rotatably supports a drum and that allows a tire mounted on a spindle shaft to be pressed against an outer peripheral surface of the drum, and a pneumatic circuit that supplies compressed air to the tire. In the tire uniformity measurement method using the device,
When reversing the rotation of the tire, the drum mechanism retracts the drum while maintaining the contact state with the tire, switches the rotation of the tire from one direction rotation to the other direction rotation, and then advances the drum. Configured so that the load can be applied to the tire,
When the rotation of the tire is reversed from one direction rotation to the other direction rotation, the pressure adjustment valve provided in the pneumatic circuit is not operated in conjunction with the backward movement of the drum. A tire uniformity test method is characterized in that the tire uniformity is measured by taking in and out compressed air having a volume substantially equal to the volume increase / decrease amount of the tire.

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