JP4451979B2 - Extrusion / molding method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an extrusion / molding method and apparatus for molding a product by supplying a strip continuously extruded from an extruder to a molding drum that is intermittently operated.
[0002]
[Prior art]
In the Japanese Patent Application Laid-Open No. 2000-246812, the present applicant supplies a thin rubber strip continuously extruded from an extruder to a forming drum, and winds the rubber strip spirally on the forming drum. Has proposed an apparatus for molding rubber products with a finished cross-sectional shape.
[0003]
This includes a conveying device having a non-extendable endless tape guided by a plurality of rollers so as to be able to move around, and by adhering and holding the rubber strip on one surface of the endless tape, the rubber strip is removed from the extruder. It is transported to the forming drum with high accuracy.
[0004]
Further, as schematically shown in FIG. 7, the conveying device a is provided with an accumulator part a1 for temporarily storing the rubber strip from the extruder b, and the extrusion speed v of the rubber strip from the extruder b which is continuously operated. And the adjustment of the speed difference and the timing difference between the supply speed v0 to the molding drum c that is intermittently operated.
[0005]
Here, as shown in FIG. 8 (A), the molding process of the product includes a molding time tw for molding the product by moving the molding drum c, and a pause time tr for which the molding drum c pauses for product removal. Is configured as one cycle, and during this one cycle, the extrusion amount k1 (= vw × tw + vr × tr) of the rubber strip extruded from the extruder b and the supply amount of the rubber strip supplied to the molding drum c k2 (= v0 × tw) is set to be substantially equal. In addition, the code | symbol vw is the extrusion speed in shaping | molding time, vr is the extrusion speed in a rest time, and it is driving | operating as vr = vw generally.
[0006]
[Problems to be solved by the invention]
Therefore, as shown in FIG. 8B, the temporal change in the storage amount g in the accumulator part a1 increases with the passage of time within the stop time tr, and the stop time (at the start of molding). The maximum value gmax (= α + tr × vr) is reached at t1, and conversely, the molding time tw decreases with time, and reaches the minimum value gmin (= α) at the start of rest (at the end of molding) t2. In addition, the code | symbol (alpha) is the extra storage part ensured for safety.
[0007]
However, strictly speaking, there is an error in the storage amount g for each cycle (indicated by a broken line) due to variations in the extrusion speeds vr and vw and the supply speed v0 due to a motor and the like, and variations in conveyance due to slippage between the roller and the endless tape. Occurs). And since this error accumulate | stores sequentially, it will result in the large storage excess or the storage shortage, and the result of causing the stop of a molding line. In particular, when rubber strips from a plurality of extruders are supplied to one molding drum to form rubber products such as raw tires, each accumulator section has excessive storage and insufficient storage separately. The risk of stopping the molding line is even higher.
[0008]
For this reason, the accumulator part a1 uses a large one having a high storage capacity, while the excess storage α is set large to cope with the excessive storage or insufficient storage, but lacks reliability. In addition, there is a problem that the apparatus and the molding line are increased in size. In particular, when a plurality of extruders are used, it may be impossible to install in a space.
[0009]
Therefore, the present invention measures the residual amount of the strip stored in the accumulator unit at the end of product molding, and adjusts the extrusion speed during the downtime based on this measurement value. The storage volume can always be restored to the reference storage volume required for product molding, the storage capacity of the accumulator unit can be minimized, the equipment and molding line can be downsized, and excessive storage and insufficient storage can occur. It is an object of the present invention to provide an extrusion / molding method and apparatus capable of reliably preventing it.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 of the present application is an extrusion / molding method, in which a product is molded by a molding drum using a strip that is continuously extruded from an extruder and transported by a conveying device. The strip that is continuously extruded and transported during a resting time Tr during which the molding drum pauses for product removal after the molding time Tw when the molding drum moves and molds the product. While providing an accumulator part that temporarily stores and the amount of storage is variable,
The standard extrusion speed at the molding time Tw of the strip by the extruder is Vw, the standard extrusion speed at the downtime Tr is Vr, and the standard feeding speed at which the strip is taken out from the accumulator section and supplied to the molding drum is V0. When the following equation (1) holds in the standard state,
At the end of one product molding, the residual amount J of the strip stored in the accumulator unit is measured, and a difference F (= S−J) from the reference storage amount S of the strip required for this product molding is obtained.
In the downtime Tr, the standard extrusion speed Vr is adjusted to the adjusted extrusion speed Vnr obtained by the following equation (2), and the strip extruded in the downtime Tr is stored in the accumulator section. It is a feature.
V0 = (Vw × Tw + Vr × Tr) / Tw −−− (1)
Vnr = F / Tr --- (2)
[0011]
According to a second aspect of the present invention, the standard extrusion speed Vw is equal to the standard extrusion speed Vr.
[0012]
According to a third aspect of the present invention, the conveying device includes a non-extensible endless tape that is guided by a plurality of rollers so as to be able to move around and holds the strip from the extruder on one side and conveys the strip to the forming drum. The accumulator part is formed by using the endless tape that stores the strip by folding back, and the strip is a rubber strip.
[0013]
The invention of claim 4 is an extrusion / molding apparatus, which uses a strip continuously extruded from an extruder and transported by a conveying device to form a product with a molding drum,
The strip that is continuously extruded and transported during a rest time Tr during which the forming drum is stopped for product removal after the forming time Tw when the forming drum is moved to form a product is temporarily stored. And an accumulator with variable storage volume,
The transport device includes a non-extendable endless tape that is guided by a plurality of rollers so as to be able to move around and holds the strip from the extruder on one side and transports the strip to the forming drum, and the accumulator section is folded back. And is formed using the endless tape for storing the strip,
The standard extrusion speed at the molding time Tw of the strip by the extruder is Vw, the standard extrusion speed at the downtime Tr is Vr, and the standard feeding speed at which the strip is taken out from the accumulator section and supplied to the molding drum is V0. When the following equation (1) holds in the standard state,
A difference F (= S−J) between the measurement unit for measuring the residual amount J of the strip stored in the accumulator unit and the reference storage amount S of the strip required for product molding is obtained at the end of one product forming. A control unit having a calculation unit and an adjustment unit for adjusting the standard extrusion speed Vr to the adjustment extrusion speed Vnr obtained by the following equation (2) in the downtime Tr;
The strip pushed out during the downtime Tr is stored in the accumulator section.
V0 = (Vw × Tw + Vr × Tr) / Tw −−− (1)
Vnr = F / Tr --- (2)
[0014]
In the invention of claim 5, the standard extrusion speed Vw is equal to the standard extrusion speed Vr.
[0015]
According to a sixth aspect of the invention, the strip is a rubber strip and is used for molding a tire.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an extrusion / molding apparatus according to a second invention capable of carrying out the extrusion / molding method according to the first invention.
[0017]
In FIG. 1, an extrusion / molding apparatus 1 includes an extruder 3 that continuously extrudes long strips, and a transport apparatus 2 that holds the extruded strip P on one surface of the endless tape 4 and integrally transports the strip P. And a forming drum 5 for forming a product by taking out and winding the strip P from the conveying device 2.
[0018]
In addition, in this example, the case where the said extrusion and shaping | molding apparatus 1 is integrated in the shaping | molding line of a green tire is illustrated. That is, the strip P is an unvulcanized rubber strip. By winding the strip P in a spiral shape, for example, an inner liner rubber, sidewall rubber, chafer rubber, breaker cushion or tread is formed on the molding drum 5. A tire component such as rubber is formed.
[0019]
As shown in FIG. 1, the extruder 3 includes an extruder main body 9 having a screw (not shown), and a roller head 10 having upper and lower calendar rolls 10U and 10L arranged at discharge ports of the extruder main body 9. The unvulcanized rubber kneaded by screw rotation and extruded from the discharge port is adjusted to a thin rubber strip P between the calender rolls 10U, 10L. Instead of the roller head 10, an extrusion head having a molding port that matches the cross-sectional shape of the strip P may be used, or an extrusion head and a roller head may be used in combination.
[0020]
In order to form the tire constituent member as in this example, it is desirable that the strip P has a thickness of about 0.2 to 2.0 mm and a width of about 10 to 50 mm, for example. In addition to this, it can be set as appropriate according to the shape size of the product to be formed.
[0021]
Further, in the present embodiment, the transport device 2 has a non-extensible endless tape 4 guided by a plurality of rollers R so as to be able to move around, as shown in FIG. , The strip P is conveyed from the extruder 3 to the forming drum 5.
[0022]
For this “holding”, the rubber adhesiveness of the strip itself is used. Therefore, as the endless tape 4, as in this example, a non-stretchable reinforcing core made of polyester fiber is coated with a polyurethane resin excellent in adhesiveness to unvulcanized rubber. Is done. Various resin materials can be selected according to the degree of adhesion with the compounded rubber forming the strip P.
[0023]
Further, the transport device 2 includes an accumulator unit 30 that stores the strip by folding the endless tape 4 and a supply unit 31 that supplies the strip to the forming drum 5 to form a tire constituent member.
[0024]
The accumulator section 30 is formed of an outward path accumulator section 30A in which the endless tape 4 travels from the extruder 3 side toward the molding drum 5 side, and a return path accumulator section 30B in which the endless tape 4 returns from the molding drum 5 side. Is done. In the present example, a preferable case is illustrated in which the forward path accumulator unit 30A is disposed above the return path accumulator unit 30B.
[0025]
Of these, the outward accumulator section 30A includes an upper guide roller R1U arranged in a horizontal row at an upper position and a lower guide roller R1L arranged in a horizontal row at a lower position. The endless tape 4 is wound in a zigzag shape while alternately turning back and forth between the upper and lower guide rollers R1U and R1L. Similarly, the return path accumulator portion 30B includes a return guide upper guide roller R2U arranged in a horizontal row at an upper position and a return guide lower roller R2L arranged in a horizontal row at a lower position. The endless tape 4 is wound in a zigzag shape while alternately folding back and forth between the upper and lower guide rollers R2U and R2L.
[0026]
The upper guide rollers R1U and R2U for the outward path and the return path are pivotally attached to horizontal fixed frames 34A and 34B fixed to the frame 33, respectively. Further, the lower guide rollers R1L and R2L for the forward path and the return path are pivotally supported by horizontal elevating frames 35A and 35B which are guided by the frame 33 so as to be movable up and down. Reference numeral 36 denotes a guide shaft that guides the elevating frames 35A and 35B vertically and horizontally. In this example, the elevating frames 35A and 35B are urged downward by their own weights, and the endless tape 4 is stretched. To do. In addition to its own weight, a weight or a spring may be used.
[0027]
On the extruder 3 side, between the accumulator portions 30A and 30B, a receiving roller Ra that receives and removes the strip from the extruder 3 and transfers it to the endless tape 4 and the endless tape 4 are synchronized with the extrusion of the strip. Are connected via a first driving roller Rb that is continuously operated. In this example, the receiving roller Ra can be repositioned from a reference position y1 where the endless tape 4 is separated from the lower calendar roll 10L to a receiving position y2 where the endless tape 4 contacts the lower calendar roll 10L by this advancement / retraction tool 37 such as a cylinder. By the contact by replacement, the leading end portion of the strip P attached to the lower calendar roll 10L is transferred to the endless tape 4 at the start of extrusion. In addition to the parallel movement as in this example, various kinds of positions such as a tilting movement around a fulcrum can be adopted as the position change of the receiving roller Ra.
[0028]
On the molding drum 5 side, a supply roller Rc for supplying a strip to the molding drum 5 and a second drive for intermittently transporting the endless tape 4 in synchronization with the molding drum 5 between the accumulator portions 30A and 30B. It connects via the roller Rd for use. The first and second driving rollers Rb and Rd are driven in linkage with the first and second electric motors M1 and M2, respectively.
[0029]
As the forming drum 5, a conventional structure can be used.
[0030]
Further, as shown in an enlarged view in FIG. 3, the supply unit 31 includes a movable body 40 that is movable in the drum axis direction via the moving means 42 on the gantry 41, and this movable body 40. Further, the roller R including the supply roller Rc and the second driving roller Rd is pivotally supported.
[0031]
In this example, the moving means 42 includes a pair of rails 43 arranged in the drum axis direction, for example, and a screw shaft 44 supported at both ends in parallel with the rails 43, and the moving means 42. A linear bearing 45 arranged on the body 40 and guided by the rail 43 and a nut portion 46 screwed to the screw shaft 44 are connected to the screw shaft 44, and a moving motor (not shown) is connected to the screw shaft 44. .
[0032]
Therefore, the moving body 40 can be moved at a predetermined moving speed and a predetermined distance in the drum axis direction by the operation of the electric motor for movement. In addition to the ball screw mechanism as in this example, various known mechanisms such as a pinion / rack mechanism can be employed as the moving means 42.
[0033]
Further, in this example, the moving body 40 is linked to the moving means 42 and is attached to the main portion 40A to which the second electric motor M2 is attached, and one end is fixed to the main portion 40A, and the other end is used for the supply. The case where it comprises the sub part 40B which attached the roller Rc of this is illustrated. In this example, the sub-portion 40B is made of an elastic plate such as a spring steel material, and can be elastically deformed up and down in the thickness direction with the fixing point j as a fulcrum. Accordingly, the sub-portion 40B is pulled downward around the fixing point j by the tension applied to the endless tape 4 by the operation of the second electric motor M2. Then, by elastic deformation, the supply roller Rc comes into pressure contact with the forming drum 5, whereby the strip P can be automatically guided and stuck to the forming drum 5. In addition, it can replace with an elastic board body as the sub part 40B, and can also use the arm body supported so that it can tilt up and down at the said point j.
[0034]
In the supply unit 31, the supply roller Rc is set to have a small diameter, so that the strip is naturally peeled off from the endless tape 4 without being folded back by its own rigidity and supplied to the forming drum 5. Further, the supply unit 31 is provided with a cutting means 47 having a cutter blade 50 for cutting the transported strip in a moving state on the upstream side of the supply roller Rc.
[0035]
Next, in the product molding process using the extrusion / molding apparatus 1 of the present invention, the molding time Tw for molding the product by the movement of the molding drum 5 and the downtime Tr for which the molding drum 5 pauses for product removal. Are configured as one cycle.
[0036]
Accordingly, as schematically shown in FIGS. 4A to 4C, the strip P continuously extruded from the extruder 3 through the molding time Tw and the downtime Tr is temporarily transferred to the outward accumulator 30A. The stored strip P is supplied to the forming drum 5 at the forming time Tw. At this time, basically, as shown in FIG. 5A, during the one cycle, the extrusion amount K1 of the strip P extruded from the extruder 3 and the supply amount of the strip supplied to the forming drum 5 are obtained. K2 is substantially equal to each other (K1 = K2).
[0037]
That is, the standard extrusion speed Vw at the molding time Tw of the strip P by the extruder 3 is Vw, the standard extrusion speed at the downtime Tr is Vr, and the strip P is taken out from the accumulator portion 30A and supplied to the molding drum 5. When the supply speed of V0 is V0, the extrusion amount K1 and the supply amount K2 can be expressed by the following equations:
K1 = Vw × Tw + Vr × Tr)
K2 = V0 × Tw
Therefore, in the standard state, the following formula (1) is established.
V0 = (Vw × Tw + Vr × Tr) / Tw −−− (1)
[0038]
Further, in one cycle in the standard state, the temporal change in the storage amount G stored in the accumulator section 30A increases as time passes within the downtime Tr, as shown in FIG. 5B. The maximum value Gmax (= (α + Tr × Vr) at the end of the suspension (at the start of product molding) T1. Conversely, at the molding time Tw, the storage amount G decreases with the passage of time, and at the start of the suspension (at the end of product molding). ) T2 becomes the minimum value Gmin (= α), where the symbol α is an extra reserved amount to be secured for safety.
[0039]
The “standard state” includes variations in the extrusion speed and supply speed of the motors M1 and M2 themselves, as well as variations in conveyance due to slippage between the driving rollers Rb and Rd and the endless tape 4. It is assumed that there is nothing at all, and means an operating state when the extrusion speed during the downtime, the extrusion speed during the molding time, and the supply speed are each set constant. In general, in the standard state, the extrusion speed Vr during the pause time and the extrusion speed Vw during the molding time are often equal, that is, Vr = Vw.
[0040]
However, in actuality, speed variation or the like occurs, and an error occurs in the extrusion amount K1 or the supply amount K2 for each cycle.
[0041]
Therefore, in the present invention, the control means 12 (shown in FIG. 2) is provided, and the residual amount J (that is, the storage amount G) of the strip P stored in the accumulator portion 30A is measured every time T2 when product molding is completed. Then, by adjusting the extrusion speed during the downtime Tr based on this measured value, the storage amount G at the product molding start time T1 is always returned to the reference storage amount S required for product molding.
[0042]
Specifically, the control unit 12 includes a measurement unit that measures the residual amount J stored in the accumulator unit 30A, and a calculation unit that obtains a difference F (= S−J) between the reference storage amount S required for product molding, An adjusting unit that adjusts the extrusion speed during the downtime Tr from the standard extrusion speed Vr to the adjusted extrusion speed Vnr determined by the following equation (2).
Vnr = F / Tr --- (2)
[0043]
Specifically, as shown in FIG. 6, for example, the measuring unit sets the height L at which the residual amount becomes substantially zero as the reference position N, and sets the distance L of the lifting frame 35A from the reference position N. While measuring, from the distance L, the residual amount J is calculated by converting it to the length of the strip P, for example. In this example, the measurement unit is composed of a linear sensor provided in the bearing unit 13 that slides on the guide shaft 36, and the distance L is converted from the amount of vertical movement thereof. The reference position N can be set as appropriate.
[0044]
Further, the calculation unit obtains a difference F (= S−J) between the residual amount J and a reference storage amount S required for product molding. The “reference storage amount S required for product molding” is a storage amount required at the time T1 when the product molding is started in the standard state, and when the reference position is N as in this example,
S = α + Tr × Vr
As shown.
[0045]
Further, the adjustment unit adjusts the standard extrusion speed Vr to the adjustment extrusion speed Vnr during the downtime Tr based on the equation (2). In this example, a servo motor and an inverter motor capable of controlling the rotational speed are adopted as the first electric motor M1, and the adjustment push-out is performed by changing a command voltage or changing a power supply frequency by inverter control. Adjust to speed Vnr.
[0046]
As described above, the residual amount J of the accumulator portion 30A is measured every time T2 when product molding is completed, and the extrusion speed of the downtime Tr is adjusted to Vnr based on this measured value. Therefore, the storage amount G can always be returned to the reference storage amount S (constant) at the time T1 when the product molding starts.
[0047]
As a result, it is possible to reduce the extra storage α to be secured for safety, and it is possible to minimize the storage capacity itself of the accumulator unit 30A, and to reduce the size of the extrusion / molding apparatus 1 and the molding line. In addition, it is possible to reliably prevent line stoppage due to excessive storage or insufficient storage, and not only reliability in production but also productivity can be greatly improved.
[0048]
In particular, when rubber strips such as green tires are formed by supplying strips P from a plurality of extruders 3 to one molding drum 5, it is ensured that each accumulator unit 30 will cause excessive storage or insufficient storage. Moreover, since each accumulator part 30 can be reduced in size, it is also possible to increase the degree of freedom of the arrangement.
[0049]
As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.
[0050]
【The invention's effect】
As described above, the present invention measures the remaining amount of the strip stored in the accumulator unit at the end of product molding, and adjusts the extrusion speed during the downtime based on this measured value. Therefore, the storage amount at the start of product molding can always be restored to the reference storage amount required for product molding, and the storage capacity of the accumulator unit can be minimized, while the device and molding line can be reduced in size. It is possible to reliably prevent the occurrence of excessive or insufficient storage.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of an extrusion / molding apparatus that can carry out the extrusion / molding method of the present invention.
FIG. 2 is a side view showing a transport device.
FIG. 3 is a side view showing a supply means.
FIG. 4 is a diagram conceptually showing the storage states of (A) to (C).
FIG. 5A is a diagram for explaining the flow of a strip in one cycle of product molding, and FIG. 5B is a diagram showing increase / decrease in the amount of storage in an accumulation portion.
FIG. 6 is a diagram illustrating a control unit.
FIG. 7 is a diagram for explaining the prior art.
FIGS. 8A and 8B are diagrams illustrating the problem. FIGS.
[Explanation of symbols]
2 Conveying device 3 Extruder 4 Endless tape 5 Molding drum 12A Measuring unit 12B Calculation unit 12C Adjusting unit 30, 30A Accumulator unit G Storage amount P Strip R Roller

Claims (6)

Using a strip that is continuously extruded from an extruder and transported by a conveying device to a molding line that is molded into a product by a molding drum,
The strip that is continuously extruded and transported during a rest time Tr during which the forming drum is stopped for product removal after the forming time Tw when the forming drum is moved to form a product is temporarily stored. And providing an accumulator with variable storage volume,
The standard extrusion speed at the molding time Tw of the strip by the extruder is Vw, the standard extrusion speed at the downtime Tr is Vr, and the standard feeding speed at which the strip is taken out from the accumulator section and supplied to the molding drum is V0. When the following equation (1) holds in the standard state,
At the end of one product molding, the residual amount J of the strip stored in the accumulator unit is measured, and a difference F (= S−J) from the reference storage amount S of the strip required for this product molding is obtained.
In the downtime Tr, the standard extrusion speed Vr is adjusted to the adjusted extrusion speed Vnr obtained by the following equation (2), and the strip extruded in the downtime Tr is stored in the accumulator section. A characteristic extrusion / molding method.
V0 = (Vw × Tw + Vr × Tr) / Tw −−− (1)
Vnr = F / Tr --- (2) 2. The extrusion / molding method according to claim 1, wherein the standard extrusion speed Vw is equal to the standard extrusion speed Vr. The transport device includes a non-extendable endless tape that is guided by a plurality of rollers so as to be able to move around and holds the strip from the extruder on one side and transports the strip to the forming drum, and the accumulator section is folded back 3. The extrusion / molding method according to claim 1, wherein the endless tape for storing the strip is used to form the strip, and the strip is a rubber strip. Using a strip that is continuously extruded from an extruder and transported by a conveyor, it is molded into a product by a molding drum,
The strip that is continuously extruded and transported during a rest time Tr during which the forming drum is stopped for product removal after the forming time Tw when the forming drum is moved to form a product is temporarily stored. And an accumulator with variable storage volume,
The transport device includes a non-extendable endless tape that is guided by a plurality of rollers so as to be able to move around and holds the strip from the extruder on one side and transports the strip to the forming drum, and the accumulator unit is folded back. And is formed using the endless tape for storing the strip,
The standard extrusion speed at the molding time Tw of the strip by the extruder is Vw, the standard extrusion speed at the downtime Tr is Vr, and the standard feeding speed at which the strip is taken out from the accumulator and supplied to the molding drum is V0. When the following equation (1) holds in the standard state,
A difference F (= S−J) between the measurement unit for measuring the residual amount J of the strip stored in the accumulator unit and the reference storage amount S of the strip required for product molding is obtained at the end of one product forming. A control unit having a calculation unit and an adjustment unit for adjusting the standard extrusion speed Vr to the adjustment extrusion speed Vnr obtained by the following equation (2) in the downtime Tr;
An extrusion / molding apparatus characterized in that a strip that is extruded during the downtime Tr is stored in the accumulator section.
V0 = (Vw × Tw + Vr × Tr) / Tw −−− (1)
Vnr = F / Tr --- (2) 5. The extrusion / molding apparatus according to claim 4, wherein the standard extrusion speed Vw is equal to the standard extrusion speed Vr. 6. The extrusion / molding apparatus according to claim 4, wherein the strip is a rubber strip and is used for molding a tire.

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