JPH10286824A - Rotation control method for warming screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the proper warming temperature by the rotation of screws. SOLUTION: Screws 30 and 32 for transferring and warming a rough fabric while providing the fabric with shear force are rotated in the reverse directions each other by motors 50 and 52 respectively, The number of rotations of the screw 32 driven by the motor 52 is. varied by a controller 54 based on the temperature sensed by a temperature sensor 56 and the temperature preset as the warming temperature while keeping the number of rotations of the screw 30 driven by the motor 50. When the temperature sensed by the temperature sensor is too high, the number of rotations of the screw 32 is reduced, while when the temperature sensor is too low, the number of rotations of the screw 32 is increased to maintain the temperature sensed by the temperature sensor constant by the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber kneading step for kneading and kneading prior to the processing of rubber dough such as natural rubber and the like, and a heat for kneading or kneading the rubber dough. The present invention relates to a rotation control method for an input screw.

[0002]

2. Description of the Related Art Tires and the like for automobiles are manufactured by vulcanization molding of natural rubber or the like. The raw rubber (coarse material) such as natural rubber used for the vulcanization molding is a viscoelastic body and needs to be an elastoplastic body prior to processing. For this purpose, the raw dough is subjected to mastication and kneading in which a compounding agent for mixing into a rubber dough suitable for the product to be heated and processed is mixed.

[0003] The raw material is converted from a viscoelastic material to an elastoplastic material by being heated in a rubber kneading process. This warming reduces the viscoelastic properties of the rough dough and increases its plasticity by mechanically applying a shearing force to the rough dough.

In general, in the rubber kneading process, the coarse dough is supplied into a pair of heating cylinders each having a screw provided therein, and the coarse dough is alternately pushed from one cylinder to the other by rotation of the screw. A Banbury-type kneading machine is used in which the heat is transferred while the heat is accelerated by the shear force generated in the coarse dough. This kneader is similar in structure to an extruder, but the extruder is provided with a head for narrowing the discharge amount at the tip, whereas the kneader used for kneading the rubber has a protruding amount. Squeezing increases the temperature of the rubber material and decreases the discharge rate. For this reason, heat management becomes difficult, so the head is removed from the extruder.

[0005] Screws provided in pairs are controlled by a single driving means so as to be rotated in the same direction at the same rotational speed. Thereby, the fin provided spirally on the screw is driven to rotate while maintaining a certain phase.

By the way, when performing the warming of the rough dough or the like, it is necessary to control the temperature of the rough dough to be constant. For this purpose, the rubber material in the cylinder is maintained at a predetermined temperature by controlling a heating means for supplying hot water or the like around the cylinder provided with the screw.

[0007]

However, maintaining the temperature of the self-heating coarse dough properly with hot water or the like while rotating the screw at a constant speed by the same driving means results in extremely low thermal efficiency. Sometimes. Further, when the temperature of the rubber material in the cylinder has changed, it takes time to return this temperature.

[0008] The present invention has been made in view of the above facts, and proposes a method of controlling the rotation of a screw for heating which can increase the heat efficiency when heating rubber cloth and maintain the heating temperature appropriately. The purpose is to do.

[0009]

The invention according to claim 1 is
By rotating and driving screws arranged in a pair of cylinders provided in parallel to each other, rubber dough is fed from one cylinder to the other cylinder and transferred while stirring to heat the heat. A method of controlling the rotation of a screw, wherein a driving unit is provided for each of the screws, a temperature detecting unit detects the temperature of the rubber material that has been heated, and based on the detection result, at least one of the driving units. The rotation of the screw is controlled such that the temperature detected by the temperature detecting means becomes a predetermined temperature by controlling.

According to the present invention, the driving means is provided so that the screws provided in pairs are driven separately. At least one of these driving means is controlled to change the rotation speed of the screw based on the detection result of the temperature detecting means.

[0011] For example, by reducing the number of rotations of the screw, the shearing force acting on the rubber material transferred by the screw can be reduced to suppress heat generation. Also, by increasing the number of rotations of the screw, the calorific value of the rubber material can be increased, and the temperature can be increased.

As described above, by changing the calorific value of the rubber material by the rotation of the screw, the temperature of the rubber material in the cylinder can be easily and appropriately maintained at a desired heat input temperature. As a result, it is possible to control the viscosity of the rubber cloth by using the detected temperature of the rubber cloth as a parameter, and to control the hot work of the rubber cloth.

The invention according to claim 2 is characterized in that the rotation is controlled based on the detection result of the temperature detecting means while the rotation ratio of the pair of screws is kept at a predetermined value.

According to the present invention, the heat input efficiency becomes highest when the rotation speeds of the two screws provided in the pair are the same. Further, the temperature of the rubber cloth to be heated can be controlled by changing the rotation speed.

[0015] From this, by controlling the rotation speed based on the detection result of the temperature detecting means while maintaining the rotation speed of the two screws the same, it is possible to maintain the appropriate temperature without lowering the heat input efficiency. Controlled heating can be performed.

The invention according to a third aspect is characterized in that the screws provided in pairs are driven to rotate in mutually different directions.

According to the present invention, the rubber material is transferred while rotating the screws in opposite directions. Thereby, the rubber dough can be uniformly stirred between the two screws, so that the temperature of the rubber dough can be maintained uniform and the heat can be input.

[0018]

1 to 3 show a schematic configuration of a kneading machine 10 applied to the present embodiment. In addition,
The coarse material 12 such as natural rubber to be applied to the present embodiment is heated and kneaded by mastication, and after kneading in which the compounding agent is mixed thereafter, re-kneading is performed as necessary. It is a rubber fabric for forming rubber products. In the present embodiment, the kneading machine 10 for performing the kneading will be described. However, the present invention is not limited to the kneading and can be applied to a kneading machine for performing kneading and re-kneading.

As shown in FIG. 1, the kneading machine 10 has a jacket 18 in which cylinders 14 and 16 each having a cylindrical shape are arranged so that their axes are parallel to each other. Hot water of a predetermined temperature is supplied to the jacket 18 by a hot water supply means (not shown) for heating, and the cylinders 14 and 16 are maintained at a substantially constant temperature.

In the cylinders 14 and 16,
Chambers 20 and 22 into which 2 is charged are formed. These chambers 20, 22 are
The portions 16 are notched along the axial direction so that they communicate with each other. As a result, the coarse dough 12 heated between the chambers 20 and 22 alternately moves between the chamber 20 and the chamber 22 by rotation of the screw described later, and is efficiently heated and heated by applying a shearing force. It has become so.

As shown in FIG. 2, the kneading machine 10 has one end of the cylinders 14 and 16 in the axial direction (hereinafter referred to as "base 2").
4 ”) is provided with a hopper 26. The lower end of the hopper 26 is open to the chambers 20 and 22. The coarse dough 12 is transferred from the hopper 26 to the chamber 2.
0 and 22 are input.

The inner diameters of the cylinders 14 and 16 forming the chambers 20 and 22 are fixed, and the screws 3 are inserted into the chambers 20 and 22 from the base 24 side.
0 and 32 are inserted and arranged, and the coarse dough 12 fed from the hopper 26 is transferred through the chambers 20 and 22 by the screws 30 and 32 and is pushed out from the discharge port 28 at the end opposite to the base 24. It is. In addition, the discharge port 28
The warm dough 12 extruded from is stretched in a belt shape by, for example, a roller pair as a rubber dough for processing,
It is sent to the next process.

The screw 30 is constituted by a rotating shaft 34 and fins 36 formed in a spiral shape on the outer peripheral surface of the rotating shaft 34.
A fin 38 is formed on the outer peripheral surface of the rotating shaft 34 in a spiral shape. The screws 30 and 32 are
6 and the fins 38 have substantially the same shape except for the directions of
Hereinafter, the screw 30 will be mainly described, and the description of the screw 32 will be omitted.

The rotation shaft 34 of the screw 30 is
The enlarged diameter portion 40 corresponding to the inner diameter dimension of the cylinder 14 is formed on the side of the cylinder 14.
4 and cantilevered.

The rotating shaft 34 of the screw 30 is
The enlarged diameter portion 40 extends in a range of a predetermined length along the axial direction from 0.
A base 42 having a further reduced outer diameter is provided, and is formed in a tapered shape in which the outer diameter is gradually reduced from the base 42 toward the end in the direction opposite to the enlarged diameter portion 40. The screw 30 is formed in a tapered shape by gradually reducing the diameter of the rotary shaft 34 from the base 42 to the distal end, thereby reducing the weight of the distal end side and hardly causing a run-out even in a cantilevered state. Has become.

Around the base 42 of the rotating shaft 34, a biting portion 44 is formed by fins 36 formed at regular intervals. In the biting portion 44, the coarse dough 12 fed from the hopper 26 is finely divided. While pushing it into the chamber 20.

In the chamber 20, the rotating shaft 34
Is gradually reduced, so that the distance between the outer peripheral surface of the rotating shaft 34 and the inner peripheral surface of the cylinder 14 is gradually increased. The screw 30 has an inclination angle θ (flight angle) of the above-mentioned fin 36 with respect to the inner peripheral surface of the cylinder 20. The transfer section 46 is gradually enlarged in accordance with the inclination of the surface.

The fin 36 in the transfer section 46 has an inclination angle θ.
Is changed, the opening area of the space between the adjacent fins 36 along the axial direction is made substantially constant. Therefore, the interval between the fins 36 adjacent in the axial direction of the rotation shaft 34 is gradually narrowed toward the tip of the rotation shaft 34. The screw 30 has an L / D of 4 to 4 when the outer diameter (the inner diameter of the cylinder 14) is D with respect to the length L from the biting portion 44 to the tip.
8, the outer diameter dimension D with respect to the length L, that is, the inclination gradient when the rotating shaft 34 is formed in a tapered shape is set. The shear force of the screw 30 is increased by the fins 36 having an inclination angle θ corresponding to the inclination gradient.

As shown in FIG. 3, motors 50 and 52 serve as driving means for the screws 30 and 32, respectively.
Are connected. By transmitting the driving force of these motors 50 and 52 to the enlarged diameter portion 40 of the rotating shaft 34, the screws 30 and 32 are rotated in predetermined directions, respectively. At this time, in the present embodiment, the screw 30 is rotationally driven in the direction of arrow B, and the screw 32 is
It rotates in the direction of arrow C opposite to 0. In this way, by rotating in different directions (opposite directions), the coarse dough 12 that moves alternately in the chambers 20 and 22 is uniformly stirred.

The motors 50 and 52 are connected to a controller 54, and the rotation of the motors is controlled by the controller 54.

A temperature sensor 56 is connected to the controller 54 as temperature detecting means. The temperature sensor 56 is provided between the chamber 20 and the chamber 22.
The temperature of the rough dough 12 transferred to a predetermined position in the inside is detected. The temperature sensor 56 may be provided in one of the chambers 20 and 22, or may be provided in both the chambers 20 and 22.

The controller 54 controls the motors 50 and 52 based on the temperature detected by the temperature sensor 56 so as to maintain the raw material 12 transferred in the chambers 20 and 22 at a predetermined temperature. For example, when the temperature detected by the temperature sensor 56 decreases, the motor 50 or the motor 52 is controlled so that the rotation speed of at least one of the screws 30 and 32 increases.

[0033] As shown in FIG. 4, the temperature T of the coarse fabric 12 is NetsuIri varies according to the rotation speed N _b of the rotational speed N _a and screw 32 of the screw 30. That is, when changing the rotational speed N _a of the screw 30, kept by changing the rotational speed N _b of the screw 32 in accordance with a change in the rotational speed N _a, the temperature T of the coarse fabric 12 substantially constant be able to.

[0034] Therefore, as shown in FIG. 5, when you are the rotational speed N _a screw 30 is constant, by increasing or decreasing the rotational speed N _b of the screw 32, increasing or decreasing the temperature T of the coarse fabric 12 Can be. That is,
By changing the rotation speed of at least one of the screws 30, 32, the heat input temperature of the rough dough 12 can be changed according to the change in the rotation speed.

This is because the rotation speed N of the screws 30 and 32 is
_a, in response to a change in N _b, in order to change the shearing force with the transfer rate, heating value changes. The temperature of the coarse dough 12 changes due to the change in the amount of heat generated.

From here, the controller 54 controls the number of rotations of the screws 30 and 32 based on the detection result of the temperature sensor 56, so that the rough dough 12 is kept at a predetermined heating temperature and heat is applied. I have to.

[0037] In the present embodiment, as an example, a screw 32 that is rotated by a motor 52 to the rotational speed N _a of the screw 30 that is rotated by a motor 50 at a constant, based on a detection result of the temperature sensor 56 and so as to increase or decrease the rotational speed N _b. Further, around the cylinders 14 and 16, the chamber 2 is heated with hot water or the like.
Heating means for heating the coarse dough in 0 and 22 is provided, and the coarse dough 12 to be heated is maintained at a predetermined heat-in temperature while being supplementarily heated by the heating means.

Hereinafter, the operation of the present embodiment will be described.
When the heat input temperature T _W is set prior to the start of the heat input of the coarse dough 12, the kneading machine 10 controls the motors 50 and 52 according to the map shown in FIG. 4 and the set heat input temperature T _W. Drive. Thus, the screws 30 and 32 are driven to rotate at a rotation speed corresponding to the heat input temperature T _W. In the kneading machine 10,
Heat input is performed while maintaining the heat input temperature T _W within a range of 90 ° C. to 130 ° C. for a predetermined time.
_W and the transfer speed of the coarse dough 12 depending on time, that is,
The number of rotations of the screws 30 and 32 is set.

[0039] Incidentally, as shown in FIG. 6, when the rotational speed ratio of the screw 30,32 (N _a / N _b) is "1" (N _a = N _b), the heat input temperature, time, the discharge amount When the heat input efficiency in consideration of the above is set to “1”, the heat input efficiency with respect to the rotation speed ratio becomes highest when the rotation speed ratio is “1”. That is, the heat input efficiency is best, the rotation speed N _b is substantially the same (N _a = N the rotational speed N _a and screw 32 of the screw 30
_b ) It is time to initially set the screws 30, 32 to the same rotational speed.

When the kneaded dough 12 is fed from the hopper 26, the kneading machine 10
Is pushed into the chambers 20 and 22 by the biting portion 44. The coarse dough 12 pushed into the chambers 20 and 22 is transferred to the discharge ports 28 of the cylinders 14 and 16 via the transfer unit 46, and is extruded from the discharge ports 28 as rubber dough having a predetermined viscosity which is heated.

The screws 30 and 32 transport the coarse dough 12 while twisting it along the fins 36 formed in a spiral shape. At this time, the coarse material 12 passing through the transfer section 46 in which the interval between the fins 36 is gradually narrowed is rotated between the fins 36 (rotation in the direction of arrow A in FIG. ) Is increased. For this reason, the shearing force acting on the coarse dough 12 increases, and self-heating proceeds.

In this way, the coarse dough 12 is
The temperature rises due to the increase in the calorific value between 6,
By being heated by a heating means (not shown), it is transferred while being kept at a predetermined temperature, and heat is input.

At this time, the screw 30 and the screw 3
2 rotate in opposite directions, so that the chamber 20
Since the coarse dough 12 is replaced and stirred between 22, it is possible to perform uniform heating.

The controller 54 measures the temperature T, which is the actual warm-in temperature of the coarse dough 12 transferred through the chambers 20 and 22 by the temperature sensor 56, and based on the measurement result, the rotational speed of the screw 32. _Nb is controlled.

That is, as shown in FIG. 5, the temperature T _W set as the heat input temperature is the temperature T ₁ (for example, 12
0 ° C) is set to, when the screw 30 is rotated at a rotational speed n _3, the detected temperature T of the temperature sensor 56, a temperature higher than the temperature T ₁ T ₂ times, crude fabric 1
It is necessary to lower the temperature of 2. Here the controller 54
But the rotational speed N _b of the screw 32, by controlling the motor 52 so as to reduce the predetermined rotational speed by (1 step), the heating value of the crude material 12 passing through the chamber 22 is reduced, reduction in heating value Accordingly, the heat input temperature is reduced.

On the other hand, when the temperature T detected by the temperature sensor 56 becomes lower than the set temperature T ₁ (the temperature T
_{In 3} ), the temperature of the coarse dough 12 needs to be increased. At this time, the controller 54
Motor 52 so that the second rotational speed N _b is higher by one step
Control. As a result, the calorific value of the coarse dough 12 passing through the chamber 22 increases, and the heat input temperature increases.

[0047] Thus, by changing the rotational speed N _b of one of the screw 32 in accordance with the temperature detected by the temperature sensor 56, it is possible to control the heat input temperature of simply and accurately crude fabric 12 . As a result, it is possible to obtain a properly warmed rubber material.

At this time, the heat input efficiency does not decrease unless the rotational speed ratio changes significantly.

Further, for the set temperature T ₁ ,
When the temperature T detected by the temperature sensor 56 are significantly different, varying only the rotational speed N _b of the screw 32, there is a possibility to influence the finish of NetsuIri rubber material, in this case, the screw 30 Revolution N _a
It should be changed accordingly. by this,
Appropriate heating can be performed. That is, the rotation speed may be changed based on the detection result of the temperature sensor 56 while maintaining the rotation speed ratio N _a / N _b = 1 of both the screws 30 and 32.

The present embodiment described above is an example of the present invention, and the configuration of the kneading machine 10 does not limit the present invention. For example, in this embodiment,
A spiral fin 3 is attached to a rotating shaft 34 formed in a tapered shape.
Screws 30, 32 forming 6, 38 were used,
The shape of the screw is not limited to this, and a screw having a conventionally known arbitrary shape such as spiral fins formed at equal intervals on a cylindrical rotating shaft can be used. In the present embodiment, the screws 30, 32
Are rotated in opposite directions, but may be rotated in the same direction.

Further, in the present embodiment, the present invention
Although the example which applied to the kneading machine 10 which performs the mastication of 2 was demonstrated,
The present invention is not limited to the kneading machine 10, but can be provided for a kneading machine having an arbitrary configuration using a pair of screws.

[0052]

As described above, according to the present invention, since the rotation of the screw is controlled based on the detection result of the temperature detecting means, it is possible to reliably and appropriately maintain the rubber cloth at a desired heat input temperature. it can. Further, by changing the number of rotations of the two screws while keeping the number of rotations of the two screws the same, an excellent effect of enabling appropriate heat input without lowering the heat input efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view taken along an axial direction of a cylinder showing a screw according to an embodiment.

FIG. 2 is a schematic cross-sectional view taken along a direction orthogonal to an axial direction of a cylinder showing the kneading machine applied to the present embodiment.

FIG. 3 is a block diagram schematically showing driving of a screw.

FIG. 4 is a diagram showing the relationship between the rotation speed of one screw and the rotation speed of the other screw using the temperature of the raw material as a parameter.

FIG. 5 is a diagram showing the relationship between the rotation speed of the other screw and the temperature of the crude material when the rotation speed of one screw is used as a parameter.

FIG. 6 is a diagram showing a change in heat input efficiency with respect to a change in a rotation speed ratio of two screws.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Kneader 12 Crude material (rubber material) 14, 16 Cylinder 20, 22 Chamber 30, 32 Screw 36, 38 Fin 50, 52 Motor (drive means) 54 Controller 56 Temperature sensor (temperature detection means)

Claims (3)

[Claims] 1. A rubber material is fed from one cylinder to another cylinder and is transferred while stirring to heat-heat by rotating a screw disposed in a pair of cylinders provided in parallel with each other. A method of controlling the rotation of the heat input screw at the time, wherein a driving means is provided for each of the screws, a temperature detecting means detects the temperature of the hot rubber material, and the driving is performed based on the detection result. A method for controlling the rotation of the heat input screw, wherein the rotation of the screw is controlled so that the temperature detected by the temperature detecting means becomes a predetermined temperature by controlling at least one of the means. 2. The heat input screw according to claim 1, wherein the rotation is controlled based on the detection result of the temperature detection unit while the rotation ratio of the pair of screws is maintained at a predetermined value. Rotation control method. 3. The screw provided in a pair is driven to rotate in directions different from each other.
Or the method of controlling the rotation of the heat input screw according to claim 2.