JP7587149B2 - Apparatus and method for suppressing time-dependent deformation of unvulcanized rubber member - Google Patents

Description

The present invention relates to an apparatus and method for suppressing deformation over time of an unvulcanized rubber member, and more specifically, to an apparatus and method for suppressing deformation over time of an unvulcanized rubber member that is simple and highly versatile and can effectively suppress deformation over time of an unvulcanized rubber member.

In the process of manufacturing rubber products such as tires, long unvulcanized rubber members are extruded by a calendar device or rubber extruder, and these unvulcanized rubber members are processed to the required length and shape for use. It is known that such unvulcanized rubber members deform over time due to residual stress, etc. If the deformation over time of the unvulcanized rubber member (e.g. shrinkage in the longitudinal direction) is excessive, problems will occur such as the unvulcanized rubber molded product made using the unvulcanized rubber member not having the shape as designed, or unnecessary gaps will be generated between the unvulcanized rubber members.

In order to suppress the shrinkage of the unvulcanized rubber member in the longitudinal direction, it has been proposed to vibrate the conveyor to impart vibration to the unvulcanized rubber member being conveyed by the conveyor (see Patent Document 1). The applied vibration reduces the shrinkage of the unvulcanized rubber member, but the degree of shrinkage (shrinkage rate) varies depending on the applied vibration frequency (see paragraph 0028 and FIG. 8 of Patent Document 1). In more detail, the vibration frequency that can effectively suppress the shrinkage of the unvulcanized rubber member depends on the specifications of the unvulcanized rubber member (size, shape, type of rubber, extrusion conditions, etc.). Therefore, in order to suppress the shrinkage in a short time, it is necessary to set an appropriate vibration frequency for each specification of the unvulcanized rubber member. Therefore, there is room for improvement in order to simply and effectively suppress the time-dependent deformation of unvulcanized rubber members of various specifications.

Japanese Patent Application Publication No. 8-244090

The object of the present invention is to provide a simple and highly versatile device and method for suppressing deformation over time of unvulcanized rubber members that can effectively suppress deformation over time of unvulcanized rubber members.

To achieve the above object, the present invention provides an apparatus for suppressing deformation over time of an unvulcanized rubber member, which comprises a mounting section on which an extruded unvulcanized rubber member is placed, and a vibrator for vibrating the mounting section, characterized in that the mounting section comprises a cylindrical body and a core member that is inserted into the cylindrical body and supports the cylindrical body so that the cylindrical body can rotate and move freely in the radial direction of the cylindrical body, the unvulcanized rubber member is placed in contact with the outer peripheral surface of the cylindrical body, and vibrations generated by the vibration generated by the vibrator are transmitted to the cylindrical body via the core member.

The method of suppressing deformation over time of an unvulcanized rubber member of the present invention is a method of suppressing deformation over time of an unvulcanized rubber member, which applies vibration to the unvulcanized rubber member by vibrating a mounting part on which an extruded unvulcanized rubber member is placed, characterized in that the mounting part has a cylindrical body and a core member that is inserted into the cylindrical body and supports the cylindrical body so that the cylindrical body can rotate and move freely in the radial direction of the cylindrical body, the unvulcanized rubber member is placed in contact with the outer peripheral surface of the cylindrical body, and vibrations generated by excitation with a vibrator are indirectly transmitted to the cylindrical body via the core member.

According to the present invention, vibrations generated by excitation with a vibrator are indirectly transmitted to the cylindrical body via the shaft core material. As a result, vibrations having a greater number of effective peak amplitudes over a wider frequency range are applied to the unvulcanized rubber member placed in contact with the cylindrical body, compared to when vibrations are simply applied by excitation with a vibrator. As a result, the present invention can effectively suppress deformation over time in unvulcanized rubber members of various specifications, and is simple yet highly versatile.

1 is an explanatory diagram illustrating a side view of a conveying route on which an apparatus for suppressing deformation over time of an unvulcanized rubber member according to the present invention is installed; 2 is an explanatory diagram illustrating the time-dependent deformation suppression device of FIG. 1 in an enlarged side view. FIG. 3 is an explanatory diagram illustrating the time-dependent deformation suppression device of FIG. 2 in a plan view. 3 is an explanatory diagram illustrating the shaft core and the cylindrical body of FIG. 2 in cross section; FIG. 5 is an explanatory diagram illustrating a vibration waveform on a rotating roller caused by excitation by a vibrator; FIG. 4 is an explanatory diagram illustrating a vibration waveform in a cylindrical body caused by excitation by a vibrator. FIG. 10 is an explanatory diagram illustrating a vibration waveform in a cylindrical body when the outer diameter of the shaft core material is 20 mm. FIG. 10 is an explanatory diagram illustrating a vibration waveform in a cylindrical body when the outer diameter of the shaft core material is 25 mm. FIG. 10 is an explanatory diagram illustrating a vibration waveform in a cylindrical body when the cylindrical body has an inner diameter of 31 mm. FIG. 10 is an explanatory diagram illustrating a vibration waveform in a cylindrical body when the cylindrical body has an inner diameter of 35 mm. FIG. 10 is an explanatory diagram illustrating vibration waveforms in a cylindrical body when the material of the cylindrical body is changed. FIG. 13 is an explanatory diagram showing a side view of another example of installation of a time-dependent deformation suppression device on a conveying path. FIG.

The device and method for suppressing deformation over time of an unvulcanized rubber member of the present invention will be described below based on the embodiment shown in the figures.

The device 1 for suppressing deformation over time of an unvulcanized rubber member (hereinafter, referred to as the suppression device 1) of the present invention, illustrated in Figures 1 to 4, accelerates the deformation over time of a long unvulcanized rubber member R and terminates it early. This suppresses the occurrence of large deformation over time in the unvulcanized rubber member R. The extruded long unvulcanized rubber member R generally shrinks over time in the longitudinal direction, and this shrinkage causes deformation that increases over time in the width and thickness directions. Therefore, the suppression device 1 accelerates the longitudinal shrinkage of the unvulcanized rubber member R and the associated increase over time in the width and thickness directions, and terminates it early. In the following embodiment, an unvulcanized rubber member R extruded by a calendar device 10 will be described as an example, but the present invention can also be applied to an unvulcanized rubber member R extruded by other equipment such as a rubber extruder.

The suppression device 1 includes a placement section 2 on which the extruded unvulcanized rubber member R is placed, and a vibrator 6 that vibrates the placement section 2. Furthermore, in this embodiment, the suppression device 1 includes a heating means 7 that heats the unvulcanized rubber member R placed on the placement section 2. The heating means 7 can be provided as desired.

In this embodiment, the suppression device 1 is installed on a transport path that transports the unvulcanized rubber member R extruded from the calendar device 10 to another process. A transport means 8 having a number of rotating rollers 8a arranged at intervals is installed on this transport path, and a winding drum 9 is arranged at the end of the transport path. The number of rotating rollers 8a includes not only freely rotating rollers but also at least one roller that is driven to rotate. The unvulcanized rubber member R is transported along the transport path by the driving force of this rotating roller 8a. The transported unvulcanized rubber member R is wound up on the winding drum 9 and temporarily stored until it is used in the next process.

The mounting section 2 has a cylindrical body 4 and a core member 3 that is inserted into the cylindrical body 4. Both ends of the core member 3 are joined to the frame 5, and the core member 3 is fixed to the frame 5 so that it cannot rotate. The core member 3 can also be supported by the frame 5 so that it can rotate. The core member 3 is a solid or hollow rod-like body, and in this embodiment, the cross-sectional shape is a constant solid cylinder in the longitudinal direction.

The cross-sectional shape of the core material 3 is not limited to a circle, and can be an ellipse, triangle, or polygon with more than a square, but a circular outer shape is preferable. It is also possible to use a core material 3 whose cross-section is not constant in the longitudinal direction. For example, at least one of the three longitudinal regions of the core material 3, one end, the other end, and the center, can be made to differ from the other regions in at least one of the shape or size of the cross-section.

The shaft core material 3 is made of various metals or non-metals, such as general carbon steel, stainless steel, or aluminum alloys. As non-metals, various hard resins can be used.

The cylindrical body 4 is a cylinder whose cross-sectional shape is substantially constant in the longitudinal direction. At least one of the inner and outer circumferential surfaces of the cylindrical body 4 may be provided with irregularities.

The cylindrical body 4 is formed of various metals or nonmetals, such as general carbon steel, stainless steel, or aluminum alloy. As the nonmetal, various hard resins can be used. The cylindrical body 4 and the core material 3 can be made of the same material, or they can be made of different materials. Therefore, a combination of a metallic cylindrical body 4 and a nonmetallic core material 3, a combination of a nonmetallic cylindrical body 4 and a metallic core material 3, a combination of a metallic cylindrical body 4 and a metallic core material 3, or a combination of a nonmetallic cylindrical body 4 and a nonmetallic core material 3 can be used.

As the vibration exciter 6, various known vibration exciters 6 can be used. The vibration exciter 6 is connected to the frame 5. When the vibration exciter 6 is activated, the frame 5 is vibrated, and the core material 3 is vibrated accordingly. This vibration is transmitted to the cylindrical body 4 via the core material 3. The vibration direction by the vibration exciter 6 is the radial direction of the core material 3 (cylindrical body 4). The vibration exciter 6 may be connected to the core material 3 to directly excite the core material 3 to vibrate.

As the heating means 7, various known heaters can be used. For example, a heater that heats the cylindrical body 4 or a hot air heater that directly heats the unvulcanized rubber member R can be used.

The outer diameter (maximum outer diameter) of the core material 3 is set to be larger than the inner diameter (minimum inner diameter) of the cylindrical body 4, and a gap g is formed between the outer peripheral surface of the core material 3 and the inner peripheral surface of the cylindrical body 4. As a result, the core material 3 supports the cylindrical body 4 rotatably and supports the cylindrical body 4 so that it can move freely in the radial direction of the cylindrical body 4. The cylindrical body 4 rotates around the core material 3, but the core material 3 is not fixed to the center of the cylindrical axis of the cylindrical body 4. In other words, since the cylindrical body 4 rotates with the core material 3 eccentric, the size of the gap g varies and the size of the gap g differs depending on the circumferential position of the core material 3.

The core material 3 is also slightly longer (for example, by a few mm to a few cm) than the cylindrical body 4. This allows the cylindrical body 4 to move slightly in the longitudinal direction relative to the core material 3.

Since the cylindrical body 4 is not fixed to the core material 3 but is merely inserted, the vibration is transmitted between the core material 3 and the cylindrical body 4, resulting in a characteristic vibration waveform. That is, as shown in FIG. 5, the vibration waveform VR when the freely rotating rotating roller 8a is vibrated by the vibrator 6 under the same vibration conditions is significantly different from the vibration waveform Vd (vibration waveform Vd at the cylindrical body 4) transmitted to the cylindrical body 4 via the core material 3 as shown in FIG. 6. The vibration waveform VR shown in FIG. 5 is data for a hollow cylindrical steel rotating roller 8a with an outer diameter of 61 mm. The vibration waveform Vd shown in FIG. 6 is data when a cylindrical body 4 with an inner diameter of 31 mm is inserted on a central cylindrical steel core material 3 with an outer diameter of 20 mm. The vibration waveform Vd shown in FIG. 6 has a larger number of effective peak amplitudes in a wide range of frequency bands than the vibration waveform VR shown in FIG. 5. The effective peak amplitude is, for example, 0.05 mm or more, and more preferably 0.1 mm or more. The present invention skillfully utilizes the vibration of this vibration waveform Vd to effectively suppress changes over time in the unvulcanized rubber member R. Note that the direction of the amplitude of the data shown as examples in Figures 5 and 6 and Figures 7 to 11 described below is the radial direction (vertical direction) of the cylindrical body 4.

As shown in Figures 7 and 8, when the vibration conditions by the vibrator 6 and the specifications of the cylindrical body 4 are the same and only the outer diameter of the core material 3 is different, the vibration waveform Vd (Vd1, Vd2) in the cylindrical body 4 changes in each case. The vibration waveforms Vd1 and Vd2 shown in Figures 7 and 8 are data when the outer diameters of the solid cylindrical steel core material 3 are 20 mm and 25 mm, respectively, under the common condition that the inner diameter of the steel cylindrical body 4 is 35 mm.

As shown in Figures 8 and 9, when the vibration conditions by the vibrator 6 and the specifications of the core material 3 are the same, the peripheral wall thickness of the cylindrical body 4 remains constant, and only the inner diameter is changed, the vibration waveform Vd (Vd3, Vd4) in the cylindrical body 4 changes in each case. The vibration waveforms Vd3 and Vd4 shown in Figures 8 and 9 are data for the case where the inner diameters of the steel cylindrical body 4 are 31 mm and 35 mm, respectively, under the common condition that the outer diameter of the solid cylindrical steel core material 3 is 20 mm.

As shown in FIG. 9, when the vibration conditions of the vibrator 6 and the specifications other than the materials of the core material 3 and the cylindrical body 4 are the same and only the material of the cylindrical body 4 is changed, the vibration waveform Vd (Vd5, Vd6) at the cylindrical body 4 changes in each case. In FIG. 9, the vibration waveform Vd5 (black) and the vibration waveform Vd6 (gray) are shown overlapping each other. The vibration waveforms Vd5 and Vd6 are data when the cylindrical body 4 is made of steel and resin, respectively, under the common conditions of the outer diameter of the solid cylindrical steel core material 3 being 20 mm and the inner diameter of the cylindrical body 4 being 31 mm. The vibration waveform Vd5 has a larger peak amplitude than the vibration waveform Vd6.

From the data illustrated in Figures 7 to 11, it is possible to obtain the desired vibration waveform Vd by adjusting the size of the gap g between the outer peripheral surface of the core material 3 and the inner peripheral surface of the cylindrical body 4, the combination of materials of the core material 3 and the cylindrical body 4 (the mass difference between the core material 3 and the cylindrical body 4), etc. It is therefore advisable to set these so that the vibration waveform Vd has a large number of peak amplitudes (for example, 0.05 mm or more, more preferably 0.1 mm or more) over a wide range of frequency bands. The amplitude of the vibration waveform Vd can be increased as the vibration amplitude by the vibrator 6 is increased.

Next, an example of the steps for the manufacturing method of the unvulcanized rubber member of the present invention will be described.

The calendar device 10 has multiple calendar rolls 11. Unvulcanized rubber is passed between these calendar rolls 1. By extruding the unvulcanized rubber from between the calendar rolls 11, the unvulcanized rubber is formed into a sheet-shaped unvulcanized rubber member R. The unvulcanized rubber member R is used as tire tread rubber, side rubber, etc. in a later process. The calendar device 10 can continuously manufacture multiple lots of unvulcanized rubber members R with the same specifications, or it can manufacture unvulcanized rubber members R with one specification and then manufacture unvulcanized rubber members R with different specifications.

The unvulcanized rubber member R extruded from the calendar device 10 is transported to the winding drum 9 by a transport means arranged on the transport path. As shown in FIG. 2, the unvulcanized rubber member R passes through while being placed in contact with the outer circumferential surface of the cylindrical body 4 during transport. The unvulcanized rubber member R does not come into contact with the shaft core material 3.

The frame 5 is vibrated by the vibrator 6 while the unvulcanized rubber member R is being transported. If necessary, the heating means 7 is also operated. As the frame 5 is vibrated, the core material 3 is also vibrated and vibrates. The vibration of the core material 3 is transmitted to the cylindrical body 4 via the core material 3. The vibration waveform transmitted to the cylindrical body 4 becomes a vibration waveform having a large number of effective peak amplitudes over a wide frequency band, as shown in FIG. 5.

As a result, vibrations of this vibration waveform function effectively to promote time-dependent deformation in unvulcanized rubber members R of various specifications and to terminate the changes over time early. In other words, there is no need to set the vibration frequency for each specification of the unvulcanized rubber member R, and it is highly versatile because it can effectively suppress the time-dependent deformation of the unvulcanized rubber member R. In addition, it has a simple configuration in which the core material 3 is inserted into the cylindrical body 4, the cylindrical body 4 is supported so that it can rotate and move freely in the radial direction of the cylindrical body 4, and vibration is transmitted to the cylindrical body 4 via the core material 3.

Making at least one of the cylindrical body 4 and the core material 3 nonmetallic is advantageous for reducing noise caused by interference between the cylindrical body 4 and the core material 3. On the other hand, if both the cylindrical body 4 and the core material 3 are nonmetallic, vibrations in the cylindrical body 4 are absorbed, making it difficult to ensure a large amplitude. As a result, it is disadvantageous for effectively suppressing deformation of the extrusion R over time.

Therefore, making one of the cylindrical body 4 and the core material 3 metallic and the other non-metallic is advantageous for increasing the amplitude of vibration in the cylindrical body 4 while reducing noise caused by interference between the cylindrical body 4 and the core material 3. Making the cylindrical body 4 non-metallic rather than metallic makes it easier to reduce its weight, which is advantageous for increasing the amplitude of vibration in the cylindrical body 4 as a result of the reduced weight. Therefore, it is advisable to make the cylindrical body 4 non-metallic and the core material 3 metallic.

The unvulcanized rubber member R may have a uniform shape in the width direction, such as a rectangle, in the cross section, but may also have a non-uniform shape in the width direction. In an unvulcanized rubber member R of such a shape, the degree of deformation over time varies in the width direction. Therefore, in order to effectively suppress the deformation over time in response to the different degree of deformation over time in the width direction, at least one of the shape or size of the cross section of the core material 3 may be designed to change in the longitudinal direction. Specifically, when the thickness of the unvulcanized rubber member R is greater in the center than at both ends in the width direction, the outer diameter of the core material 3 having a circular outer shape is made larger or smaller in the center than at both ends in the longitudinal direction. When the thickness of the unvulcanized rubber member R increases from one end in the width direction to the other end, the outer diameter of the core material 3 having a circular outer shape is made larger or smaller from one end in the longitudinal direction to the other end.

The heating temperature of the unvulcanized rubber member R by the heating means 7 is set lower than the temperature at which the vulcanization of the unvulcanized rubber member R proceeds without delay, but is set to a moderately high temperature. For example, the heating means 7 heats the unvulcanized rubber member R to about 70°C to 90°C. Heating to this temperature range is advantageous for promoting deformation over time without substantially promoting the vulcanization of the unvulcanized rubber member R.

In the transport path of the unvulcanized rubber member R shown in FIG. 12, multiple placement units 2 are installed at intervals in the transport direction. Each of the multiple placement units 2 installed at intervals in the transport direction can be set to the same specifications. In other words, the same vibration is applied to the unvulcanized rubber member R by each placement unit 2 at multiple positions spaced apart in the transport direction.

Alternatively, the multiple placement sections 2 installed at intervals in the conveying direction can be mixed with placement sections set to different specifications. For example, the frequency distribution of the effective peak amplitude of the vibration applied to the unvulcanized rubber member R by each placement section 2 can be made different at multiple positions spaced apart in the conveying direction.

Using the same conveying path as shown in FIG. 1, unvulcanized rubber members with a square cross section were conveyed while vibrating a single freely rotating roller in the middle of the conveying path with a vibrator (conventional example), and unvulcanized rubber members were conveyed while transmitting vibration to a single cylindrical body using the suppression device of the present invention shown in FIGS. 2 to 4 (embodiment). The deformation of each unvulcanized rubber member was measured 60 minutes after the conveying was completed and compared with that immediately after conveying. The only difference between the conventional example and the embodiment is that the vibration is applied to the unvulcanized rubber member by the above-mentioned freely rotating roller or the above-mentioned cylindrical body, and the other conditions are the same. The outer diameter of the freely rotating roller in the conventional example was 61 mm, the outer diameter of the solid cylindrical steel core material in the embodiment was 20 mm, and the inner diameter of the steel cylindrical body was 31 mm. The measurement results are shown in Table 1.

Table 1 shows the percentage increase or decrease in the measurements taken 60 minutes after the unvulcanized rubber part was transported, based on the dimensions (length, width, thickness) of the unvulcanized rubber part immediately after transport was completed. A negative percentage increase or decrease in length indicates that the part has shrunk due to deformation over time. A positive percentage increase or decrease in width and thickness indicates that the part has grown due to deformation over time.

The results in Table 1 show that the embodiment can effectively suppress the deformation over time of unvulcanized rubber components compared to the conventional example.

Reference Signs List 1: Device for suppressing deformation over time 2: Placement section 3: Core material 4: Cylindrical body 5: Frame 6: Vibrator 7: Heating means 8: Conveying means 8a: Rotating roller 9: Winding drum 10: Calender device 11: Calender roll R: Unvulcanized rubber member

Claims (8)

An apparatus for suppressing deformation over time of an unvulcanized rubber member, the apparatus comprising: a mounting section on which an extruded unvulcanized rubber member is mounted; and a vibrator for vibrating the mounting section,
The device for suppressing deformation over time of an unvulcanized rubber member is characterized in that the mounting portion has a cylindrical body and a core material that is inserted into the cylindrical body and supports the cylindrical body so that it can rotate and move freely in the radial direction of the cylindrical body, the unvulcanized rubber member is placed in contact with the outer peripheral surface of the cylindrical body, and vibrations generated by vibration excited by the vibrator are transmitted to the cylindrical body via the core material. The device for suppressing deformation over time of an unvulcanized rubber member according to claim 1, wherein one of the cylindrical body and the shaft core material is made of metal, and the other is made of nonmetal. The device for suppressing deformation over time of an unvulcanized rubber member according to claim 1 or 2, wherein a plurality of the placement sections are installed at intervals in the conveying direction on a conveying path along which the unvulcanized rubber member is conveyed to another process. The device for suppressing deformation over time of an unvulcanized rubber member according to claim 3, wherein each of the above-mentioned placement sections, which are installed at intervals in the conveying direction, is set to the same specifications. The device for suppressing deformation over time of an unvulcanized rubber member according to claim 3, wherein each of the plurality of placement sections installed at intervals in the conveying direction has different specifications. The device for suppressing deformation over time of an unvulcanized rubber member according to any one of claims 1 to 4, wherein at least one of the shape or size of the cross section of the shaft core material changes in the longitudinal direction. The device for suppressing deformation over time of an unvulcanized rubber member according to any one of claims 1 to 6, further comprising a heating means for heating the unvulcanized rubber member placed on the placement section. A method for suppressing deformation over time of an unvulcanized rubber member, comprising vibrating a mounting portion on which an extruded unvulcanized rubber member is mounted, thereby applying vibration to the unvulcanized rubber member,
The method for suppressing deformation over time of an unvulcanized rubber member is characterized in that the mounting portion is configured to have a cylindrical body and a core material that is inserted into the cylindrical body and supports the cylindrical body so that it can rotate and move freely in the radial direction of the cylindrical body, the unvulcanized rubber member is mounted in contact with the outer peripheral surface of the cylindrical body, and vibrations generated by excitation with a vibrator are indirectly transmitted to the cylindrical body via the core material.

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