JP7415519B2 - Method for applying mold release agent for tire mold and method for manufacturing tires - Google Patents

Description

The present invention relates to a method of applying a mold release agent to a tire mold, and a method of manufacturing a tire using this method of applying a mold release agent.

In the tire manufacturing method, a low cover is heated and pressurized within a mold, and a tire is obtained from this low cover. As the raw cover is heated and pressurized within this mold, the product adheres to the cavity surface of the mold. This mold is used repeatedly to mass produce tires. As this mold is used repeatedly, this product grows. The grown products spoil the appearance of the tire. The mold is then cleaned to remove this product. Such a mold cleaning method is disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2017-128013).

Japanese Patent Application Publication No. 2017-128013

This mold cleaning removes the mold release agent along with the product from the cavity surface. When the raw cover is heated and pressurized within the molding from which the release agent has been removed, the resulting tire will come into close contact with the cavity surface. This adhesion impairs the releasability of the tire. In order to suppress this adhesion, a mold release agent is applied to the cleaned cavity surface. By applying this mold release agent, the tire is prevented from coming into close contact with the cavity surface.

However, it is not easy to apply a mold release agent to the entire surface of the cavity. There is a risk that the tire may stick to areas where the release agent has not been applied. It is possible to apply a large amount of mold release agent to the entire surface of the cavity. However, applying a large amount of mold release agent requires a long application time and a long drying time. Moreover, a large amount of mold release agent deteriorates the quality of the tire and worsens the working environment.

An object of the present invention is to provide a method for applying a mold release agent for a tire mold that has excellent mold release properties, and a method for manufacturing a tire using this method for applying a mold release agent.

The method for applying a mold release agent for a tire mold according to the present invention includes:
(A) Step of recognizing the shape of the cavity surface of the mold,
(B) determining a plurality of spraying positions at which the nozzle sprays the mold release agent based on the shape of the cavity surface; and (C) the nozzle moving and spraying the mold release agent onto the cavity surface at each spraying position. Includes a spraying process.

Preferably, in the step (C), the nozzles move from each spraying position to another spraying position while the spraying of the mold release agent is stopped.

Preferably, in the step (A), a sensor moving along the movement path of the nozzle detects the shape of the cavity surface, and recognizes the shape of the cavity surface based on the detection by the sensor.

Preferably, in the step (C), an organic solvent mold release agent is sprayed onto the cavity surface.

Preferably, this method of applying a mold release agent includes, prior to the step (C),
(D) A step of cleaning the cavity surface of the mold with a laser.

The method for manufacturing a tire according to the present invention includes:
(A) Step of recognizing the shape of the cavity surface of the mold,
(B) Determining a plurality of spraying positions at which the nozzle sprays the mold release agent based on the shape of the cavity surface. (C) Spraying the mold release agent onto the cavity surface at each spraying position while the nozzle moves. process,
(D) the step of preparing a low cover;
(E) A step of putting the low cover into the mold; (F) A step of heating and pressurizing the low cover in the mold to obtain a tire from the low cover.

In the method for applying a mold release agent for a tire mold according to the present invention, the spraying position at which the nozzle sprays the mold release agent is determined based on the shape of the cavity surface. At each spraying position, the nozzle sprays the mold release agent onto the cavity surface. This coating method allows the mold release agent to be uniformly coated over the entire cavity surface. This method of applying a mold release agent has excellent tire releasability and can suppress the amount of mold release agent applied. A tire manufacturing method using this coating method provides the same effects as the release agent coating method.

FIG. 1 is a conceptual diagram showing a coating apparatus for a mold release agent coating method according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing how the coating device of FIG. 1 is used. FIG. 3 is a partially enlarged view of FIG. 2 in use.

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described in detail based on preferred embodiments, with appropriate reference to the drawings.

FIG. 1 shows a coating device 2 together with a segment 4 as a mold. The coating device 2 includes a table 6, a rail 8, a nozzle stand 10, a nozzle 12, a sensor stand 14, and a sensor 16. Although not shown, the coating device 2 further includes a control device.

Segment 4 has a circular arc shape. FIG. 1 shows a section of the segment 4 perpendicular to the circumferential direction. The segment 4 includes an inner circumferential surface 18 and a plurality of linear protrusions 20 protruding from the inner circumferential surface 18. Each stripe 20 extends in the circumferential direction. The linear protrusion 20 includes a radially inward end surface 22 and a pair of sloped surfaces 24 extending from the end surface 22 to the inner circumferential surface 18 . In this segment 4, a cavity surface 26 is formed from the inner circumferential surface 18, the end surface 22, and the slope 24. This cavity surface 26 forms the outer peripheral surface of the tire. The striations 20 form grooves in the tread of the tire.

Although not shown, this segment 4 includes a number of vent holes extending from the cavity surface 26 to its outer surface. The segment 4 further includes a vent piece that opens and closes the vent hole. Generally, vent holes form spews on the surface of the tire. By including this vent piece, the segment 4 can suppress the formation of spews. This segment 4 is a so-called spuress mold.

Although not shown, the table 6 includes fixtures for positioning and fixing the segments 4. In FIG. 1, the segment 4 is positioned and fixed on the table 6.

The rail 8 is arranged above the table 6. The rail 8 extends in the left-right direction in FIG. The nozzle stand 10 is attached to the rail 8. The nozzle stand 10 is movable along the rail 8. The nozzle 12 is attached to the nozzle stand 10. The nozzle 12 has a function of spraying the mold release agent downward.

The sensor stand 14 is attached to the rail 8. The sensor stand 14 is movable along the rail 8. The sensor 16 is attached to the sensor stand 14. The sensor 16 has a function of detecting the shape of the cavity surface 26 of the segment 4. This sensor 16 is arranged to detect the shape of the cavity surface 26 at the height of the outlet of the nozzle 12. The sensor 16 is, for example, a laser sensor, although it is not particularly limited.

In this coating device 2, the nozzle stand 10 and the sensor stand 14 are attached to the rail 8, but either one may be attached to the other rail. Further, a robot arm may be used in place of the rail 8 and the nozzle stand 10, and a robot arm may be used in place of the rail 8 and the sensor stand 14.

Although not shown, the control device includes a storage section, an arithmetic section, and an input/output section. The storage unit stores information such as control programs and various predetermined data. Examples of the storage unit include ROM, RAM, and the like. The calculation unit reads information such as a control program and various predetermined data stored in the storage unit and executes calculations. The calculation unit executes calculations based on various data input from the input/output unit. A CPU is exemplified as the calculation unit. The input/output section inputs and outputs signals to and from the sensor 16 and the like. An interface board is exemplified as the input/output unit.

The control device controls the nozzle stand 10, the nozzle 12, the sensor stand 14, and the sensor 16. The control device controls the position of the nozzle stand 10. The control device controls spraying of the mold release agent by the nozzle 12 and stopping thereof. The control device controls the position of the sensor stand 14. The control device controls detection by the sensor 16. Furthermore, the control device has a function of receiving the detection signal of the sensor 16, a function of recognizing the shape of the detection target from this detection signal, a function of storing the shape information, and a function of determining the spraying position of the nozzle 12. Equipped with

FIG. 2 shows how this coating device 2 is used. In FIG. 2, nozzle 12 is shown for spraying mold release agent onto cavity surface 26. In FIG. The nozzle 12 indicated by the solid line is located at the spraying position P1. The nozzles 12 indicated by two-dot chain lines are located at spraying positions P2 to P6. The nozzle 12 that sprays the mold release agent onto the cavity surface 26 is shown at the spraying positions P1 to P6.

In FIG. 3, a part of FIG. 2 is shown. FIG. 3 shows the nozzle 12 at the spraying position P1 and the nozzle 12 at the spraying position P2. In the nozzle 12 at the spraying position P1, the mold release agent is directly sprayed onto the slope 24 labeled 24A (hereinafter also referred to as slope 24A) and the slope 24 labeled 24B (hereinafter also referred to as slope 24B). I can't. In the nozzle 12 at the spraying position P2, the mold release agent is directly sprayed onto the slope 24A and the slope 24B.

A method for manufacturing a tire using the coating device 2 will be explained with reference to FIGS. 1 to 3.

As shown in FIG. 1, the segment 4 is positioned and fixed to the coating device 2 (STEP 1). The control device moves the sensor 16 in the axial direction (left and right direction) of the segment 4. The sensor 16 detects the shape of the cavity surface 26 of the segment 4 while moving. The control device recognizes the shape of the cavity surface 26 from the detection signal of the sensor 16 (STEP 2). In this step (STEP 2), the control device stores shape information of the cavity surface 26 of the segment 4. The control device determines spraying positions P1 to P6 based on the shape of the cavity surface 26 (STEP 3).

As shown in FIG. 2, the control device moves the nozzle 12 to the spraying position P1. The nozzle 12 sprays the mold release agent onto the cavity surface 26 at the spraying position P1. The nozzle 12 stops spraying the mold release agent after spraying for a predetermined period of time. The control device moves the nozzle 12 to the spraying position P2. The nozzle 12 sprays the mold release agent onto the cavity surface 26 at the spraying position P2. The nozzle 12 stops spraying the mold release agent after spraying for a predetermined period of time. Similarly, the nozzle 12 sprays the mold release agent onto the cavity surface 26 at spraying positions P3 to P6. In this way, the mold release agent is sprayed onto the cavity surface 26 of the segment 4 (STEP 4). This segment 4 is attached to a vulcanizer (STEP 5).

A low cover is prepared (STEP 6). This raw cover is put into a mold containing this segment 4 (STEP 7). Inside the mold, the raw cover is heated and pressurized. A tire is obtained from this low cover (STEP 8).

After the tire is obtained, the segment 4 is removed from the vulcanizer (STEP 9). The cavity surface 26 of the segment 4 is cleaned with a laser (STEP 10). The cleaned segment 4 is sent to the process (STEP 1). In this tire manufacturing method, steps (STEP 1) to (STEP 10) are repeated.

In this tire manufacturing method, the steps (STEP 9) to (STEP 5) do not have to be performed every time. After the steps (STEP 6) to (STEP 8) are repeated a predetermined number of times, the steps (STEP 9) to (STEP 5) may be executed.

Further, in the step (STEP 2), the detection by the sensor 16 does not have to be performed every time. The control device may recognize the shape of the cavity surface 26 for the segments 4 for which shape information of the cavity surface 26 has already been stored, based on the information specifying the segment 4 and the stored shape information.

As shown in FIG. 3, the nozzle 12 at the spraying position P1 cannot directly spray the mold release agent onto the slopes 24A and 24B. In this step (STEP 3), the spraying position P2 is determined as a position where the mold release agent can be applied to the slope 24A and the slope 24B. Furthermore, this spraying position P2 is determined so that the overlap between the area where the nozzle 12 at that position applies the mold release agent and the area where the nozzle 12 at the spraying position P1 applies the mold release agent is small. This spraying position P2 is preferably determined so that the overlap between the area where the nozzle 12 at that position applies the mold release agent and the area where the nozzle 12 at the spraying position P1 applies the mold release agent is minimized. .

In this step (STEP 3), spraying positions P1 to P6 are determined in this way so that the mold release agent is sprayed directly onto the entire surface of the cavity surface 26. This application method allows the mold release agent to be applied directly to the entire surface of the cavity surface 26.

In this step (STEP 4), the nozzle 12 stops spraying the mold release agent while moving from the spraying position P1 to P6. At each spray position P1 to P6, the nozzle 12 sprays mold release agent onto the cavity surface 26. This coating method can suppress the amount of the mold release agent applied while applying the mold release agent to the entire cavity surface 26.

Note that in this manufacturing method, the nozzle 12 stops spraying the mold release agent while moving from the spraying position P1 to P6, but the invention is not limited to this. A small amount of mold release agent may be applied from the nozzle 12 while moving from spraying position P1 to P6, or the nozzle 12 may apply the mold release agent intermittently during movement.

Further, in the step (STEP 3), the number of spraying positions to be determined is not limited to six. The number of spraying positions may be determined so that the mold release agent can be applied to the entire surface of the cavity surface 26. The number of spraying positions may be less than six or more than six. From the viewpoint of suppressing the amount of mold release agent applied, the spraying positions P1 to P6 are preferably determined so that the number of spraying positions is minimized.

With this coating method, since the amount of the mold release agent to be applied is suppressed, the drying time can be shortened even if the water-based mold release agent is used. The drying time can also be shortened by applying an aqueous mold release agent to the segment 4 which has been removed from the vulcanizer and is at a relatively low temperature. There is no need to apply an aqueous mold release agent to the high-temperature segment 4 attached to the vulcanizer, as is the case in the past.

In this step (STEP 4), a mold release agent may be applied directly to the entire surface of the cavity surface 26. Thereby, even if the mold release agent has quick-drying properties, the mold release agent can be uniformly applied to the entire surface of the cavity surface 26. For example, even if an organic solvent-based mold release agent is used, it is evenly applied to the entire cavity surface 26. Examples of this organic solvent include benzene, acetone, ethanol, and hexane.

In this step (STEP 2), the sensor 16 detects the shape of the cavity surface 26 along the movement path of the nozzle 12 in the step (STEP 4). The sensor 16 detects the shape of the cavity surface 26 at the position where the nozzle 12 sprays the mold release agent. Areas where the release agent cannot be applied can be detected with high precision at each of the spraying positions P1 to P6. Thereby, this nozzle 12 can uniformly apply the mold release agent to the entire surface of the cavity surface 26. From this point of view, it is preferable that the sensor 16 be arranged so that the shape of the cavity surface 26 seen from the position of the ejection port of the nozzle 12 can be detected.

This step (STEP 10) employs laser cleaning. Laser cleaning does not use shot materials like shot blasting, for example. Laser cleaning prevents shot material from clogging between the vent hole of segment 4 and the vent piece. Laser cleaning also reduces wear on the cavity surface 26. Laser cleaning can suppress discoloration on the tire surface caused by metal powder scraped off from the cavity surface 26.

On the other hand, the cavity surface 26 that has been cleaned by laser is easier to adhere to the tire than the cavity surface 26 that has been cleaned by shot blasting. On the cavity surface 26 to which no mold release agent is applied, the tire tends to stick tightly. This method of applying a mold release agent is suitable for applying a mold release agent to the cavity surface 26 which is to be cleaned with a laser.

EXAMPLES Hereinafter, the effects of the present invention will be clarified through examples, but the present invention should not be interpreted in a limited manner based on the descriptions of these examples.

[Example 1]
Using the coating apparatus shown in FIG. 1 and the tire manufacturing method of the present invention, 100 tires were obtained. In this manufacturing method, a spuress mold (mold A) was used. The cavity surface was laser cleaned. An organic solvent-based mold release agent was used as the mold release agent.

[Comparative example 1]
The cavity surface was cleaned by shot blasting. An operator manually applied a mold release agent to the entire surface of the cavity. A conventional water-soluble mold release agent was used as the mold release agent. In other respects, 100 tires were obtained in the same manner as in Example 1.

[Example 2]
100 tires were obtained in the same manner as in Example 1, except that the water-soluble mold release agent of Comparative Example 1 was used.

[Example 3]
A mold (mold B) without a vent piece for opening and closing a vent hole was prepared. This mold has a large number of fine vent holes that are always open. 100 tires were obtained in the same manner as in Example 1 except that this mold was used. A large number of spews were formed on the surface of the obtained tire due to vent holes.

[Comparative example 2]
The cavity surface was cleaned by shot blasting. An operator manually applied a mold release agent to the entire surface of the cavity. As the mold release agent, the water-soluble mold release agent of Comparative Example 1 was used. In other respects, 100 tires were obtained in the same manner as in Example 3.

[Example 4]
100 tires were obtained in the same manner as in Example 3, except that the water-soluble mold release agent of Comparative Example 1 was used.

[Tire appearance evaluation]
The exterior of the tire was inspected. The tire surface was inspected for discoloration due to metal powder. In addition, the presence or absence of bare air due to vent hole clogging was examined. The test results are shown in Table 1 as an index with Comparative Example 1 as 100. The smaller these indexes are, the lower the incidence is. The smaller these indexes are, the more preferable they are.

[Productivity evaluation]
The releasability when taking out the tire from the mold was evaluated. The results are shown in Table 1 as an index with Comparative Example 1 as 100. The smaller these indexes are, the lower the incidence of mold release defects. The smaller these indexes are, the more preferable they are.

As shown in Table 1, the manufacturing method of the example has a higher evaluation than the manufacturing method of the comparative example. From this evaluation result, the superiority of the present invention is clear.

The method described above can be widely applied to manufacturing tires using molds.

2... Coating device 4... Segment (mold)
12... Nozzle 16... Sensor 26... Cavity surface

Claims (6)

(A) Step of recognizing the shape of the cavity surface of the mold,
(B) determining a plurality of spraying positions at which the nozzle sprays the mold release agent based on the shape of the cavity surface; and (C) the nozzle moving and spraying the mold release agent onto the cavity surface at each spraying position. Including the process of spraying,
The mold includes an inner circumferential surface and a linear protrusion protruding from the inner circumferential surface, and the cavity surface includes the inner circumferential surface and a slope of the linear protrusion,
In the step (B),
A method for applying a mold release agent to a tire mold, in which a control device included in the application device determines a position where the release agent can be applied to the slope where the release agent cannot be directly sprayed at another spraying position. . The method for applying a mold release agent according to claim 1, wherein in the step (C), the nozzle moves from each spraying position to another spraying position while the spraying of the mold release agent is stopped. According to claim 1 or 2, in the step (A), a sensor moving along the movement path of the nozzle detects the shape of the cavity surface, and recognizes the shape of the cavity surface based on the detection by the sensor. How to apply a mold release agent as described. 4. The method for applying a mold release agent according to claim 1, wherein in the step (C), an organic solvent-based mold release agent is sprayed onto the cavity surface. Prior to the step (C),
The method for applying a mold release agent according to any one of claims 1 to 4, comprising the step of (D) cleaning the cavity surface of the mold with a laser. (A) Step of recognizing the shape of the cavity surface of the mold,
(B) Determining a plurality of spraying positions at which the nozzle sprays the mold release agent based on the shape of the cavity surface. (C) Spraying the mold release agent onto the cavity surface at each spraying position while the nozzle moves. process,
(D) the step of preparing a low cover;
(E) a step of putting the low cover into the mold; (F) a step of heating and pressurizing the low cover in the mold to obtain a tire from the low cover ;
The mold includes an inner circumferential surface and a linear protrusion protruding from the inner circumferential surface, and the cavity surface includes the inner circumferential surface and a slope of the linear protrusion,
In the step (B),
A method for manufacturing a tire, wherein a control device included in the coating device determines a position where the release agent can be applied to the slope where the release agent cannot be directly sprayed at another spraying position .

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