JPH0720029A - Method for preventing adhesion of rubber duct and powder scattering device for indoor abrasion test of tire - Google Patents

Abstract

PURPOSE:To perform highly accurate abrasion tests by surely preventing adhesion of rubber dust. CONSTITUTION:Since rubber adhesion preventing powder is scattered on a road surface material 16 immediately after the material 16 is separated from the tread of a rotating tire 14, an excessive amount of the rubber adhesion preventing powder is removed from the material 16 by a centrifugal force and recovered through a dust collecting hood 38. Therefore, the rubber adhesion preventing powder is adequately scattered on the material 16 and adequately transferred to the tire 14 which is rotated by the material 16 in a press- contacting state. Since the rubber adhesion preventing powder is composed of corn starch which prevents the adhesion of rubber dust to the tire 14 and white carbon which prevents the adhesion of rubber dust to the material 16, the rubber dust resulting from abrasion tests does not adhere to the tire 14 and material 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing wear rubber from adhering to a road surface and a tire in a tire indoor wear test, and a powder spraying device.

[0002]

2. Description of the Related Art Abrasion rubber produced when a tire indoor wear test is carried out adheres to a road surface or a tire tread and adversely affects test results (measurement accuracy deteriorates or tire wear condition reproducibility deteriorates). Therefore, various prevention methods have been tried.

As a typical example thereof, KWMcintosh, Tir
e Science and Tecnology, Vol1, No1, Feb 1973, and I.Go
As described in usakov et al., SAE Paper 770872 1972, a method of adsorbing wear rubber with a rubber roller or rubber tire, or one kind of wear rubber anti-adhesion powder, for example JAR.
In I (Japan Automobile Research Institute), a method of intermittently spraying talc by a falling method has been performed.

[0004]

By the way, the conventional method has the following problems. (1) In the method of adsorbing worn rubber with a rubber roller or a rubber tire, the adsorbed amount of the rubber roller or the rubber tire is limited, and the worn rubber cannot be adsorbed stably for a long time continuously. (2) For a wide range of tread rubber tires, 1
It is difficult to simultaneously prevent the abrasion rubber from adhering to two points on the road surface and the tire tread by using various kinds of abrasion rubber adhesion preventing powder. That is, it is only possible to prevent adhesion to either one. (3) The amount of powder to prevent abrasion rubber from sticking is not constant,
A small amount of powder necessary to prevent the adhesion of wear rubber,
It cannot be sprayed continuously with sufficient dispersion. (4) Immediately before the rotating tire tread touches the road surface, the wear-rubber adhesion-preventing powder is sprinkled, so that excess powder that is not used to prevent wear-rubber adhesion is scattered by the rotating tire, resulting in scattering. It is difficult to recover the powder.

In consideration of the above facts, the present invention provides a method for preventing wear rubber from adhering to a wear rubber in an indoor wear test of a tire capable of reliably preventing wear rubber from adhering and performing a highly accurate wear test. An object of the present invention is to provide a powder spraying device that can spray powders stably.

[0006]

A method for preventing adhesion of wear rubber in a tire indoor wear test according to claim 1, wherein a tire tread wear test is carried out by rotating the road surface and the tire under pressure to perform a tire tread wear test. In the method, a mixed powder comprising at least a first adhesion preventing powder for preventing adhesion of wear rubber to a tire and a second adhesion preventing powder for preventing adhesion of wear rubber to a road surface is provided on the road surface and the tire. And to prevent the wear rubber produced by the wear test from adhering to the road surface and the tire.

According to a second aspect of the present invention, there is provided a method for preventing abrasion rubber from adhering to a tire during an indoor abrasion test, the tire tread abrasion test method comprising rotating a road surface and a tire under pressure to perform an abrasion test on the tire tread. Of a mixed powder composed of a first anti-adhesion powder for preventing the adherence of the tire to the tire and a second anti-adhesion powder for preventing the wear rubber from adhering to the road surface, immediately after leaving the tread surface of the rotated tire. In addition to being sprayed by a spraying device, surplus powder that is not used for preventing the adhesion of wear rubber is recovered by a powder recovery device that is arranged near the tire side and the spraying position.

The invention according to claim 3 is used for an indoor wear test of a tire for performing a wear test of a tire tread by rotating a road surface and a tire under pressure, and the road surface and the aforesaid wear rubber produced by the wear test. A powder spraying device for spraying powder for preventing adhesion to a tire, the room being filled with powder and being supplied with gas, and being connected to an upper side of the powder surface of the room and being supplied to the room. And a discharge port for discharging and spraying a mixture of gas and powder.

Further, the invention according to claim 4 is used for an indoor wear test of a tire for performing a wear test of a tire tread by rotating a road surface and a tire under pressure, and the road surface of the wear rubber produced by the wear test. And a powder spraying device for spraying powder for preventing adhesion to the tire, the first chamber being filled with powder and being supplied with gas, and the second chamber having a volume smaller than that of the first chamber. Room and the first
An opening connecting the inside of the second chamber and the inside of the second chamber at a lower side, and a gas connected from above the opening of the second chamber and supplied from the first chamber. And a discharge port for discharging and spraying a mixture of the powder and the powder.

[0010]

According to the method of preventing adhesion of worn rubber in a tire indoor wear test according to the first aspect of the present invention, the first anti-adhesion powder for preventing adhesion of the worn rubber to the tire and the surface of the worn rubber to the road surface. The tire tread wear test is performed by applying a mixed powder consisting of the second powder for preventing adhesion to the road surface and the tire, and the wear rubber produced by the wear test is applied to the tire and the road surface under test. Does not adhere.

According to the method for preventing wear rubber from adhering to the tire in the indoor wear test according to the second aspect of the present invention, the first adhesion preventing powder for preventing the wear rubber from adhering to the tire and the wear rubber to the road surface. By spraying the mixed powder consisting of the second anti-adhesion powder for preventing adhesion onto the road surface immediately after leaving the tread surface of the rotated tire with a spraying device, the mixed powder that did not adhere to the road surface and the surplus of the road surface The mixed powder is collected by a powder collection device located near the tire side from the spraying position, and the mixed powder is sprayed appropriately on the road surface. The mixed powder on the road surface is appropriately transferred to the tire under test.

According to the powder spraying apparatus of the third aspect of the invention, when the gas is supplied to the room filled with the powder, the powder and the gas are mixed in the upper space of the powder in the room, and the mixed powder is discharged from the outlet. It is continuously discharged, and the mixed powder is evenly distributed on the road surface.

According to the powder spraying device of the invention described in claim 4, when the gas is supplied to the first chamber filled with the powder, the powder and the gas are transferred to the second chamber through the opening. Are supplied and the powder and gas are mixed in the second chamber. The gas and powder mixed in the second chamber are sprayed through the outlet connected to the upper side of the opening.

Here, the volume of the space above the mixed powder in the second chamber, that is, the volume of the portion where the air and the mixed powder are mixed, has an effect on the volume of the mixed powder inside the first chamber. Therefore, it is possible to always discharge a substantially constant amount of the mixed powder together with the air through the outlet regardless of the volume of the mixed powder inside the first chamber.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, an indoor drum tester 1
A test tire 14 is crimped to the drum 12 of 0,
Both rotate in the direction of arrow A.

A road surface material 16 having an actual road surface shape is attached to the surface of the drum 12, and the road surface material 16 of this embodiment is made of a mixture of silica sand and epoxy resin. There is.

As shown in FIGS. 1 and 2, the drum testing machine 10 includes a powder spraying device 11.

A nozzle 18 as a discharge port forming a part of the powder spraying device 11 is arranged in the vicinity of the contact portion between the tire 14 and the drum 12 in the direction of the arrow B. The nozzle 18 is connected via a duct 20 to a mixing container 22 that forms another part of the powder spraying device 11, and the tip end of the drum 12 immediately after being separated from the tire 14,
It is oriented almost at a right angle.

As shown in FIGS. 3 and 4, the mixing container 22
Is a cylindrical closed container whose axis is perpendicular to the ground. The mixing container 22 of this embodiment has an inner size of a diameter D of 430 mm and a height H of 455 mm.

The inside of the mixing container 22 is horizontally divided into two chambers by a partition plate 24, one of which is a large-volume gas supply chamber 26 as a first chamber, and the other is a second chamber. The mixing chamber 28 has a small volume. This partition plate 24 is inclined toward the gas supply chamber 26 side,
Further, the upper portion and both side portions are in close contact with the inner wall of the mixing container 22, and the lower portion forms an opening portion 30 which is separated from the bottom portion 22A of the mixing container 22 by a predetermined dimension. Partition plate 2 of this embodiment
In No. 4, the inclination angle θ with respect to the vertical direction is 5 degrees, and the inside of the mixing container 22 is divided into a volume of the gas supply chamber 26 of 96 and a volume of the mixing chamber 28 of 4. Also, the opening 3
The size of 0 is 50 mm in height dimension h and 210 mm in width w.

On the bottom side of the gas supply chamber 26, the mixing container 2
The tip of the air supply pipe 32 is provided from the outside so as to pass through 2. A plurality of air ejection holes 34 are formed in the vicinity of the tip of the air supply pipe 32, and dry compressed air supplied from a compressor (not shown) is ejected from these air ejection holes 34. Has become.

As shown in FIG. 4, the gas supply chamber 26 is filled with a rubber adhesion preventing powder 36 as a mixed powder having two kinds of compositions. It should be noted that the rubber adhesion preventing powder 36 is added to the charging port 27 provided in the upper part of the gas supply chamber 26.
It is designed to be inserted from.

The rubber anti-adhesion powder 36 comprises at least a first anti-adhesive agent for preventing abrasion rubber from adhering to the tire 14, and a second anti-adhesion agent preventing abrasion rubber from adhering to the road surface material 16 of the drum 12. It is composed of an agent.

In this embodiment, cornstarch is used as the first anti-adhesion agent, and white carbon (SiO ₂ .nH ₂ O) is used as the _second anti-adhesion agent.

When cornstarch and white carbon are used as the rubber adhesion preventing powder 36, it is preferable that 100 to 20% by weight of the weight of the starch is white carbon. It should be noted that this blending ratio is a ratio relating to the combination of corn starch and white carbon, and when another type of anti-adhesion powder is used, these blending ratios are appropriately changed.

As shown in FIGS. 1 and 2, a dust collector connected to a dust collecting device (not shown) as a powder collecting device 37 is arranged along the outer periphery of the drum 12 in the direction of the arrow B from the tip of the nozzle 18. The hood 38 is arranged horizontally.

As shown in FIG. 2, the dust collecting hood 38 has a width W1 wider than that of the tire 14, and the lower end thereof is disposed near the surface of the drum 12 as shown in FIG. .

Next, the operation of this embodiment will be described. When the gas supply chamber 26 of the mixing container 22 is filled with the rubber adhesion preventing powder 36 and the compressed air is continuously ejected from the air ejection holes 34, the air is sent into the mixing chamber 28 through the opening 30, and The rubber adhesion preventing powder 36 in the gas supply chamber 26 is fed into the mixing chamber 28 through the opening 30.

In the mixing chamber 28, the air and the rubber adhesion preventing powder 36 are mixed so that the rubber adhesion preventing powder 36 is uniformly dispersed in the air, and the rubber adhesion preventing powder 36 dispersed in the air is mixed with the duct 20. Surface of the drum 12 immediately after being separated from the tire 14 via the nozzle 18, that is, the road surface material 1
It spouts continuously toward the surface of 6.

Here, the spraying amount of the rubber adhesion preventing powder 36 can be adjusted by adjusting the gas supply amount.

In general, considering the case where a predetermined amount of powder is put in a closed container and gas is supplied to the inside, the amount of powder occupying the mixture of powder and air discharged from the discharge port provided at the upper part. (G / sec) is obtained by multiplying the powder amount by the following formula (1).

[0033] The “volume of the portion where the gas and the powder are mixed” in the above formula (1) indicates the volume of the space above the rubber adhesion preventing powder 36 of the mixing chamber 28 in the present embodiment, and “the volume of the gas to be supplied” The “volume” indicates the volume of air ejected from the air ejection holes 34 of the air supply pipe 32.

In this embodiment, the volume of the space above the rubber adhesion preventing powder 36 in the mixing chamber 28 with respect to the volume of the rubber adhesion preventing powder 36 inside the gas supply chamber 26, that is, air and the rubber adhesion preventing powder 36. Since the volume of the portion mixed with 36 is not affected, in this embodiment, a constant amount of rubber adhesion preventing powder 36 can be discharged together with air regardless of the volume of rubber adhesion preventing powder 36. Therefore, it is possible to discharge the rubber anti-adhesion powder 36 for a longer time than before when the same amount of the rubber anti-adhesion powder 36 is used without discharging an unnecessary amount of the rubber anti-adhesion powder 36. Becomes Further, since the volume of the mixing chamber 28 increases upward, the upper portion of the rubber adhesion preventing powder 36 in the mixing chamber 28 is increased with respect to the increasing rate of the volume of the rubber adhesion preventing powder 36 in the mixing chamber 28. The reduction rate of the volume of the space portion tends to decrease, and the change of the discharge amount with respect to the volume change of the rubber adhesion preventing powder 36 in the mixing chamber 28 can be suppressed.

The rubber adhesion preventing powder 36 ejected from the nozzle 18 adheres to the outer peripheral surface of the road surface material 16. Here, since the drum 12 is rotating at high speed, the surplus rubber adhesion preventing powder 36 is separated from the road surface material 16 by centrifugal force. Road material 1
Excessive rubber adhesion preventing powder 36 separated from 6 and the rubber adhesion preventing powder 36 ejected from the nozzle 18 and not adhering to the road surface material 16 flow along the rotational direction near the outer peripheral surface of the drum 12 (arrow D). ) Is carried to the downstream side in the rotation direction of the drum.

Since the dust collecting hood 38 is arranged on the downstream side of the nozzle 18 in the rotating direction of the drum 12, the rubber adhesion preventing powder 36 carried by the air flow is collected through the dust collecting hood 38. Collected in the device.

In this way, the road surface material 16 is made of rubber composed of cornstarch for preventing the wear rubber from adhering to the tire 14 and white carbon for preventing the wear rubber from adhering to the road surface material 16 of the drum 12. Anti-adhesion powder 36
Of the road surface material 16 is appropriately dispersed, and the road surface material 16 is also applied to the tire 14 during the abrasion test in which the road surface material 16 is pressed and rotated.
The upper rubber adhesion preventing powder 36 is appropriately transferred.

Therefore, the abrasion rubber generated by the abrasion test does not adhere to the road surface material 16 of the tire 14 and the drum 12, and the tire 14 adheres to the road surface material 16 by a proper amount of the rubber adhesion preventing powder 36. On the other hand, since unnecessary slip does not occur, the tire wear test can be performed accurately and stably.

In the present embodiment, since the tire 14 is not interposed between the nozzle 18 and the dust collecting hood 38 as in the conventional case, the rubber adhesion preventing powder 36 ejected from the nozzle 18 is transferred to the drum 1.
2 is conveyed along the circumferential direction and does not scatter to the outside of the drum 12 in the axial direction. Moreover, in this embodiment, since the dust collecting hood 38 is provided near the downstream side of the nozzle 18, the dust collecting efficiency is extremely high. Further, since the amount of the rubber adhesion preventing powder 36 ejected from the nozzle 18 is stable, the dust can be stably collected.

Test Example 1 The effect of preventing abrasion rubber from adhering was tested using a small truck tire having a natural rubber tread.

For the test, a total of three types of powders, a cornstarch single powder, a white carbon single powder, and a rubber adhesion-preventing powder consisting of 80% by weight of cornstarch and 20% by weight of white carbon, were prepared. Abrasion test with a small truck tire running on the road surface material immediately after the tread has been separated, each powder is continuously sprayed at a target of 200 g / hour (see Fig. 1), and the presence or absence of wear rubber is checked. It was The results of these experiments are shown in Table 1 below.

[0042]

[Table 1]

[Test Example 2] A spraying method according to a comparative example, in which the rubber adhesion preventing powder 36 is sprayed on a road surface material (hereinafter, abbreviated as front road surface) immediately before the tread of the rotating tire 14 comes into contact with the road surface material 16. (Refer to FIGS. 9 and 10), the tread of the rotating tire 14 is sprayed on the road surface material (hereinafter abbreviated as the rear road surface) immediately after the tread of the rotating tire 14 is separated from the road surface material 16, and the tire is applied to each tire. The relationship between the amount of wear of 14 and the amount of spray was examined. The results of these tests are shown in FIG.
And shown in FIG.

In the method according to the comparative example, as shown in FIG. 6, when the application amount of the rubber adhesion preventing powder 36 changes, the wear amount of the tire also changes. This is because when the rubber adhesion preventing powder 36 is sprayed from the front, a large amount of the rubber adhesion preventing powder 36 gets in between the tire and the road surface and easily slips, and the friction work amount (sending force x slippage) that governs the wear amount. This is because the amount) increases and the amount of wear increases. Further, in this method, the rubber adhesion preventing powder 36 was scattered to the side of the tire (see FIG. 10, arrow C), and the recovery could not be performed satisfactorily.

On the other hand, according to the method of the present invention for spraying the rubber adhesion preventing powder 36 on the rear road surface, as shown in FIG. 5, even if the spray amount changes, the wear amount of the tire is hardly affected. Further, according to this method, the rubber adhesion preventing powder 36 does not scatter to the side of the tire, so that the surplus rubber adhesion preventing powder 36 can be reliably collected (see FIG. 2).

[Test Example 3] In order to examine the stability of the spray amount, the mixing container 22 of the present invention (see FIG. 3) was prepared, and the relationship between the powder weight in the container and the powder spray amount was investigated. The initial powder weight was 30 kg. The results of these tests are shown in FIG.

In the mixing container 22 of the present embodiment in which the value of I in the above-mentioned formula (1) hardly fluctuates, as shown in FIG. 7, the spray amount is irrespective of the amount of the rubber adhesion preventing powder 36 in the mixing container 22. It is almost constant.

In this example, cornstarch was used as the first anti-adhesion agent, but other types of starch such as wheat starch, potato starch, and soluble starch may be used as the first anti-adhesion agent. Well, powders other than these starches may be used as long as they can prevent abrasion rubber from adhering to the rubber of the tire.

Further, in this embodiment, white carbon was used as the second anti-adhesion agent, but as the second anti-adhesion agent, other than white carbon, for example, clay (dry powder of clay), talc, oxidation is used. Magnesium, activated clay,
Kaolin or the like may be used, and powders other than those described above may be used as long as they can prevent abrasion rubber from adhering to the road surface material 16 of the drum 12.

Further, in the above-mentioned embodiment, the mixing container 22 having the two chambers of the gas supply chamber 26 and the mixing chamber 28 is used, but the present invention is not limited to this, and as shown in FIG.
You may use the mixing container 112 which does not divide the inside.

As shown in FIG. 8, the mixing container 112 is a cylindrical closed container, and the rubber adhesion preventing powder 36 is contained therein in about 2/3. The duct 20 is the mixing container 11
2, the air supply pipe 32 is arranged on the bottom 112A inside the mixing container 112.

In this mixing container 112, the air ejection holes 34
When dry air is jetted from the rubber, the rubber adhesion preventing powder 36 rises in the space above the rubber adhesion preventing powder 36 of the mixing container 112, and the rubber adhesion preventing powder 36 and the air are mixed in this space, and the mixed air passes through the duct 20. When the dry air is continuously ejected from the nozzle 18 (not shown in FIG. 8), the rubber adhesion preventing powder 36 is ejected continuously from the nozzle 18.

[0053]

According to the first aspect of the present invention, there is provided a method for preventing abrasion rubber from adhering to a tire in an indoor abrasion test, comprising: a first anti-adhesion powder for preventing abrasion rubber from adhering to a tire; Since the adhesion preventing mixed powder composed of the second adhesion preventing powder for preventing the adhesion of the tire is applied, the abrasion rubber generated by the abrasion test does not adhere to the tire and the road surface, and the tire tread It has an excellent effect that a wear test can be performed with high accuracy.

According to a second aspect of the present invention, in the method for preventing wear rubber from adhering to a tire in an indoor wear test, the first adhesion preventing powder for preventing the wear rubber from adhering to the tire and the adhesion of the wear rubber to the road surface are provided. Since the anti-adhesion mixed powder consisting of the second anti-adhesion powder for preventing the above is sprayed on the road surface immediately after separating from the tread surface of the rotated tire, the surplus anti-adhesion mixed powder causes centrifugal force. Since it is removed by the method, it has an excellent effect that the wear test of the tire tread can be performed accurately without causing the tire to slip, and the powder recovery device arranged near the side opposite to the tire side from the spraying position. Since the surplus adhesion preventing mixed powder is collected, it has an excellent effect that the scattered adhesion preventing mixed powder can be prevented from scattering around.

Further, since the powder spraying device of the invention according to claim 3 has the above-mentioned constitution, the powder can be continuously discharged from the discharge port and sprayed uniformly, and the wear test of the tire tread can be carried out accurately. It has the excellent effect of being able to perform well.

Further, since the powder spraying device of the invention described in claim 4 has the above-mentioned structure, it is possible to discharge a substantially constant amount of powder continuously from the discharge port, and to effectively use the powder without waste. It has an excellent effect that the wear test of the tire tread can be performed accurately by utilizing it.

[Brief description of drawings]

FIG. 1 is a side view of an indoor drum tester according to an embodiment of the present invention.

FIG. 2 is a plan view of the drum testing machine shown in FIG.

FIG. 3 is a perspective view of a mixing container.

4 is a vertical cross-sectional view of the mixing container shown in FIG.

FIG. 5 is a graph showing the relationship between the amount of powder applied and the amount of tire wear when the method of the present invention is applied.

FIG. 6 is a graph showing the relationship between the amount of powder sprayed and the amount of wear of the tire when sprayed from the front of the tire (FIGS. 9 and 10).

FIG. 7 is a graph showing the relationship between the weight of powder in the container and the amount of powder dispersed when the mixing container of the present invention is used.

FIG. 8 is a perspective view of a mixing container according to another embodiment.

FIG. 9 is a side view of the drum tester when spraying from the front of the tire.

FIG. 10 is a plan view of the drum testing machine shown in FIG.

[Explanation of symbols]

 11 Powder Dispersing Device 14 Tire 16 Road Surface Material 18 Nozzle (Discharge Port, Powder Dispersing Device) 22 Mixing Container (Powder Dispersing Device) 26 Gas Supply Chamber (First Room) 28 Mixing Chamber (Second Room) 30 Opening 36 Rubber adhesion preventing powder (mixed powder) 37 Powder collecting device 38 Dust collecting hood (powder collecting device) 112 Mixing container

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiro Kitamura 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Hideyuki Nakamura 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation ( 72) Inventor Masaharu Ohba 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (4)

[Claims] 1. A method of preventing wear rubber from adhering to a tire in an indoor wear test of a tire tread in which a road surface and a tire are pressure-bonded and rotated to perform a wear test of a tire tread. A mixed powder composed of a prevention powder and a second adhesion prevention powder for preventing adhesion of wear rubber to a road surface is applied to the road surface and the tire, and the wear rubber generated by an abrasion test is used for the road surface and the tire. A method for preventing wear rubber from adhering to a tire in an indoor wear test, the method comprising: 2. A method for preventing wear rubber from adhering to a tire in a tire indoor wear test, wherein a tire tread wear test is performed by rotating a road surface and a tire under pressure, the first adhesion being for preventing at least wear rubber from adhering to the tire. The second to prevent adhesion of anti-powder and wear rubber to the road surface
The mixed powder consisting of the anti-adhesion powder of No. 1 is sprayed on the road surface immediately after separating from the tread surface of the rotated tire with a spraying device, and the excess powder not used to prevent the wear rubber from sticking is applied to the tire side from the spraying position. A method for preventing adhesion of worn rubber in an indoor wear test of a tire, characterized by collecting with a powder collecting device arranged in the vicinity of the side opposite to. 3. The tire is used for an indoor wear test of a tire to perform a wear test of a tire tread by rotating a road surface and a tire under pressure, and prevents abrasion rubber generated by the wear test from adhering to the road surface and the tire. A powder spraying device for spraying powder, comprising: a room filled with powder and supplied with gas; and a room connected to the upper side of the powder surface of the room and mixing the gas and powder supplied to the room. A powder spraying device comprising a discharge port for discharging and spraying a body. 4. A tire is used for an indoor wear test of a tire tread in which a road surface and a tire are pressure-bonded and rotated to prevent wear rubber produced by the wear test from adhering to the road surface and the tire. A powder spraying device for spraying powder, comprising: a first chamber filled with powder and supplied with a gas; a second chamber having a smaller volume than the first chamber; and the first chamber. An opening that connects the inside of the second chamber to the inside of the second chamber, and a gas and powder that are connected to the upper side of the opening of the second chamber and are supplied from the first chamber. And a discharge port for discharging and spraying a mixture of