JP2019198831A - Kneading device - Google Patents

Abstract

To provide a kneading device that can suppress variation in kinetic viscosity of core paste in a short kneading time.SOLUTION: The kneading device comprises a stirring bar 3 which rotates with a rotary shaft as a center in a kneading space 2a formed in a kneading pot 2 and has a stirring pin 3a extended in parallel to the rotary shaft and an injection piston 6 that charges core paste 7 kneaded in the kneading space 2a into an injection-molding die adjacent to the kneading pot 2. The kneading device moves at least part of the core paste 7 remaining in the injection-molding die side of the kneading space 2a to an input port 2b side into which a subsequent core material 8 is put, by rotating the stirring bar 3 before kneading the subsequent core material 8.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a kneading apparatus.

There is known an apparatus for kneading a core material by rotating a stirring bar disposed in a kneading space in a kneading pot.
Patent Document 1 discloses a kneading apparatus including a stirring pin arranged in parallel to the rotation axis of a stirrer and an injection piston that passes through the stirring pin and can slide toward the injection port in the kneading space. Has been.

JP-A-2006-195990

The inventors have found the following problems regarding the kneading apparatus.
In the kneading apparatus disclosed in Patent Document 1, the core material is kneaded by rotating the stirring bar. The kneaded core material constitutes a core paste. The core paste is filled in the injection mold by sliding the injection piston toward the injection port. The filled core paste is solidified in an injection mold. The solidified core paste constitutes the core. Further, after the core paste is injected, the next core material is put into the kneading space.

  When the injection piston slides toward the injection port, part of the core paste may remain on the injection port side of the kneading space. Since the injection mold is heated when the core paste is filled, the temperature becomes high. The injection port of the kneading space communicates with the cavity of the injection mold. Therefore, the injection port side end of the kneading pot becomes hot when the injection mold is heated. Therefore, the core paste remaining on the injection port side of the kneading space becomes high temperature. When the remaining core paste reaches a high temperature, the moisture content decreases due to drying.

  The remaining core paste is kneaded with the next core material to form the next core paste. The remaining core paste has a lower water content than the next core material. Since a plurality of materials having different moisture contents are kneaded, the kinematic viscosity of the next core paste is likely to vary. By sufficiently kneading the remaining core paste and the next core material, variation in kinematic viscosity of the next core paste can be suppressed. However, in order to suppress variations in kinematic viscosity of the core paste, it is necessary to lengthen the kneading time.

  This invention is made | formed in view of such a problem, and it aims at providing the kneading apparatus which can suppress the dispersion | variation in kinematic viscosity of a core paste in short kneading | mixing time.

  One aspect for achieving the above object is that the kneading space provided in the kneading pot rotates around the rotation axis and has a stirring pin extending in parallel with the rotation axis, and is kneaded in the kneading space. An injection piston that fills an injection mold adjacent to the kneading pot with the core paste, and before the next core material is kneaded, by rotating the stirring bar, At least a part of the core paste remaining on the injection mold side of the kneading space is moved to the inlet side into which the next core material is charged.

  In the kneading apparatus according to the present invention, by rotating the stirring bar before kneading the next core material, at least a part of the core paste remaining on the injection mold side of the kneading space is Move to the inlet side where the next core material is charged. Therefore, the remaining core paste and the next core material can be uniformly kneaded in a short time. Therefore, variation in kinematic viscosity of the core paste can be suppressed in a short kneading time.

  ADVANTAGE OF THE INVENTION According to this invention, the kneading apparatus which can suppress the dispersion | variation in kinematic viscosity of a core paste can be provided in short kneading | mixing time.

It is sectional drawing of the kneading apparatus which concerns on this Embodiment. It is sectional drawing of the kneading apparatus which inject | emitted the core paste. It is sectional drawing of the kneading apparatus with which the stirring pin was rotated. It is sectional drawing of the kneading apparatus with which the next core material was thrown in. It is a flowchart which shows the procedure which concerns on an Example.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

  First, the configuration of the kneading apparatus according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, the kneading apparatus 1 includes a kneading pot 2, a stirrer 3, a linear actuator 4, and an injection piston 6. In FIG. 1, a core paste 7 is also shown. In FIG. 1, the alternate long and short dash line represents the rotation axis of the stirring bar 3.

  As a matter of course, the right-handed xyz orthogonal coordinates shown in FIG. 1 and other drawings are convenient for explaining the positional relationship of the components. Usually, the z-axis positive direction is vertically upward, and the xy plane is a horizontal plane, which is common between the drawings.

  The kneading pot 2 is provided with a kneading space 2a inside. Further, the kneading pot 2 is provided with a charging port 2b and an injection port 2c. The injection port 2c communicates with a cavity of an injection mold (not shown). The core material is charged into the kneading space 2a from the charging port 2b. The charged core material is kneaded in the kneading space 2a. The kneaded core material constitutes the core paste 7. The core paste 7 is injected from the injection port 2c and filled into the cavity of the injection mold.

  As shown in FIG. 1, a stirring bar 3 is disposed in the kneading space 2a. The stirrer 3 can rotate around the rotation axis shown in FIG. The stirrer 3 includes a stirring pin 3a and a rotation base 3b. The rotation base 3b is a disk-shaped member disposed perpendicular to the rotation axis. A drive gear (not shown) is disposed on the peripheral edge of the rotation base 3b. The drive gear is meshed with the edge of the rotation base 3b. The drive gear is connected to a stirrer motor (not shown). When the stirrer motor is driven, the drive gear rotates about the rotation axis of the stirrer 3. As the drive gear rotates, the stirrer 3 rotates about the rotation axis.

  The stirring pin 3a extends in parallel with the rotation axis from the surface of the rotation base 3b on the injection port 2c side. The position where the stirring pin 3a is disposed is not particularly limited as long as it is a surface on the injection port 2c side of the rotation base 3b. For example, the stirring pins 3a are arranged radially around the rotation axis. Further, the stirring pin 3a may be arranged in an S shape so as to be point-symmetric with respect to the rotation axis of the stirring bar 3. The shape of the stirring pin 3a is not particularly limited as long as it is a columnar shape extending in parallel with the rotation axis. The stirring pin 3a has, for example, a circular cross section. Further, the stirring pin 3a may have a rectangular cross section.

  A linear actuator 4 is installed at the end of the kneading pot 2 opposite to the injection port 2c, as shown in FIG. The linear actuator 4 includes a ball nut 4a, a ball screw 4b, and a geared motor 4c. When the geared motor 4c is driven, the ball nut 4a rotates around the rotation axis. A ball screw 4b passes through the center of the ball nut 4a.

  A spiral groove is provided on the side surface of the ball screw 4b. The groove provided in the ball screw 4b is engaged with the ball nut 4a. Therefore, the ball screw 4b can be rotated about the rotation axis by rotating the ball nut 4a by driving the geared motor 4c. When the ball screw 4b is rotated about the rotation axis, the ball screw 4b advances and retreats in parallel with the rotation axis.

  An injection piston 6 is connected to the end of the ball screw 4b on the injection port 2c side. In the example shown in FIG. 1, a rotatable ball screw 4b is connected to the center of the injection piston. That is, the ball screw 4b can allow the injection piston 6 to rotate. The injection piston 6 is always in contact with the inner peripheral surface of the kneading pot 2, in other words, the wall surface of the kneading space 2a. Therefore, the injection piston 6 slides on the wall surface of the kneading space 2a as the ball screw 4b advances and retreats.

  As shown in FIG. 1, a stirring pin 3a passes through the injection piston 6. Therefore, when the stirring bar 3 rotates, the injection piston 6 rotates together with the stirring pin 3a. That is, the injection piston 6 does not hinder the rotation of the stirring bar 3. Further, the injection piston 6 can advance and retreat in parallel with the rotation axis without being influenced by the stirrer 3.

  When kneading the core material in the kneading apparatus 1, first, the injection piston 6 is arranged so as to be positioned closer to the linear actuator 4 than the charging port 2b. Next, the core material is charged into the kneading space 2a from the charging port 2b. Next, the stirrer 3 is rotated by driving the stirrer motor. The core material charged into the kneading space 2 a is kneaded by the rotation of the stirring bar 3.

  The kneaded core material constitutes the core paste 7. The core material is a solid material or a liquid material. The solid material is foundry sand. The foundry sand is natural sand, for example. The foundry sand may be artificial sand. The liquid material is a solid material binder. The liquid material is, for example, water glass. The core paste 7 may contain an additive in addition to the core material.

  After sufficiently kneading the core paste 7, the injection piston 6 is slid toward the injection port 2c. The core paste 7 is injected from the injection port 2 c by sliding of the injection piston 6. The core paste 7 injected from the injection port 2c is filled in the cavity. The core paste 7 filled in the cavity is solidified. The solidified core paste 7 constitutes a core. The core manufactured using the kneading apparatus according to the present invention is used, for example, for manufacturing an in-vehicle engine component.

  Next, with reference to FIGS. 2-4, the operation | movement at the time of throwing in the next core material to the kneading apparatus which concerns on this Embodiment is demonstrated. FIG. 2 is a cross-sectional view of the kneading apparatus in which the core paste is injected. FIG. 3 is a cross-sectional view of the kneading apparatus in which the stirring pin is rotated. FIG. 4 is a cross-sectional view of the kneading apparatus in which the next core material is charged. 2 to 4 also show the core paste 7 and the next core material 8. 2 to 4 indicate the rotation axis of the stirrer 3.

  The injection piston 6 slides toward the linear actuator 4 after injecting a sufficient amount of core paste 7. And it arrange | positions so that it may be located in the linear actuator 4 side rather than the insertion port 2b. As shown in FIG. 2, a part of the core paste 7 remains on the injection port 2c side of the kneading space 2a even after the injection is completed.

  When the core paste 7 filled in the cavity is solidified, the injection mold is heated. The injection port 2c is adjacent to the cavity. Therefore, when the injection mold is heated, the temperature at the injection port 2c side of the kneading space 2a becomes high. Therefore, the core paste 7 remaining on the injection port 2c side of the kneading space 2a is dried.

  By rotating the stirring bar 3, as shown in FIG. 3, part or all of the remaining core paste 7 can be moved to the charging port 2b side of the kneading space 2a. Further, the remaining core paste 7 can be loosened. When moving the core paste 7 toward the charging port 2b, for example, the stirrer 3 is rotated in the opposite direction to that during kneading.

  In the example shown in FIG. 3, the stirrer 3 is provided with a stirrer pin 3a so that the core paste 7 can be moved toward the rotation axis during kneading. Therefore, the core paste 7 can be moved toward the wall surface of the kneading space 2a by rotating the stirring bar 3 in the opposite direction to that during kneading.

  The remaining core paste 7 is kneaded with the next core material 8 shown in FIG. 4 to constitute the next core paste. The remaining core paste 7 has a smaller water content than the next core material 8. Therefore, in order to make the kinematic viscosity of the next core paste uniform, it is necessary to sufficiently knead the remaining core paste 7 and the next core material 8.

  Before the remaining core paste 7 and the next core material 8 are kneaded, the remaining core paste 7 is moved toward the inlet 2b by the rotation of the stirrer 3 to shorten the time. The kinematic viscosity of the next core paste can be made uniform by kneading. A core paste with a uniform kinematic viscosity is less likely to cause poor filling. Therefore, the core manufactured using the kneading apparatus 1 can accurately model the cooling circuit of the vehicle-mounted engine.

  The core paste 7 is moved by the rotation of the stirrer 3 before, for example, the next core material 8 is charged. The movement of the core paste 7 by the rotation of the stirrer 3 may be performed after the next core material 8 is charged. Further, the stirring bar 3 may be rotated while feeding the next core material 8.

  The rotational speed of the stirrer 3 when moving the remaining core paste 7 is appropriately determined. For example, when the remaining core paste 7 is moved before the next core material 8 is charged, the stirrer 3 is rotated at a faster speed than when the core paste 7 is kneaded. When the next core material 8 is charged and the remaining core paste 7 is moved, the stirrer 3 is rotated at a slower speed than when the core paste 7 is kneaded. With the configuration described above, variation in kinematic viscosity of the core paste can be suppressed in a short kneading time.

  Next, an embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flowchart illustrating the procedure according to the embodiment. Table 1 is a table | surface which shows the procedure which concerns on the Example of this invention. Table 2 is a table | surface which shows the result of having measured the kinematic viscosity of the Example of this invention.

  In the embodiment of the present invention, as shown in FIG. 1, after the injection of the core paste was completed, the first rotation process (step S1) was performed. When performing the first rotation process (step S1), the stirrer 3 was rotated clockwise at 200 rpm for 2 seconds. By performing the first rotation step (step S1), the core paste 7 remaining on the injection port 2c side of the kneading space 2a was moved to the charging port 2b side of the kneading space 2a.

  Next, the 1st material injection | throwing-in process (step S2) was performed. In the first material charging step (step S2), either one of a solid material and a liquid material is charged into the kneading space 2a from the charging port 2b. The first material charging step (step S2) was performed in a state where the rotation of the stirrer 3 was stopped or in a state where the stirrer 3 was rotated clockwise at 15 rpm.

  Next, the 2nd rotation process (step S3) was performed. When performing the second rotation step (step S3), the stirring bar 3 was rotated clockwise at 200 rpm for 2 seconds. By performing the second rotation step (step S3), the core paste 7 remaining on the injection port 2c side of the kneading space 2a was moved to the charging port 2b side of the kneading space 2a.

  Next, the 2nd material input process (step S4) was performed. In the second material input process (step S4), the material that has not been input in the first material input process (step S2) out of the solid material and the liquid material is input into the kneading space 2a from the input port 2b. The second material charging step (step S4) was performed in a state where the rotation of the stirrer 3 was stopped or in a state where the stirrer 3 was rotated clockwise at 15 rpm.

  Next, a kneading step (step S5) was performed. When performing the kneading step (step S5), the stirrer 3 was rotated counterclockwise at 170 rpm. The kneading step (step S5) was performed so that the total rotation time of the stirrer 3 was 44 seconds with the first rotation step (step S1) and the second rotation step (step S3).

  In Examples 1 to 5, the first material input process (step S2) and the second material input process (step S4) were performed under the conditions shown in Table 1. The results of measuring kinematic viscosity for Examples 1 to 5 are shown in Table 2. The numerical values shown in Table 2 are “average value ± 3σ”. When the order of adding the solid material and the liquid material was changed, the variation in kinematic viscosity of the next core paste changed.

  As shown in Table 2, when kneading was performed under the conditions of Example 1 among Examples 1 to 5, variation in kinematic viscosity of the next core paste was most suppressed. In particular, when the first rotating step (Step S1) is not performed and the second rotating step (Step S3) is performed under the conditions of Example 1, the variation in kinematic viscosity of the next core paste is the most. I was able to suppress it.

  With the invention according to the present embodiment described above, it is possible to provide a kneading apparatus capable of suppressing variations in kinematic viscosity of the core paste in a short kneading time.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention. In the above, the case where this invention was applied to the technique which knead | mixes the core paste for casting was demonstrated. However, the present invention can be applied to any technique as long as it is a kneading apparatus for kneading materials in the apparatus. For example, the present invention can be applied to a kneading apparatus for kneading food or a kneading apparatus for kneading concrete.

DESCRIPTION OF SYMBOLS 1 Kneading apparatus 2 Kneading pot 2a Kneading space 2b Input port 2c Injection port 3 Stirrer 3a Stirring pin 3b Rotating base 4 Linear actuator 4a Ball nut 4b Ball screw 4c Geared motor 6 Injection piston 7 Core paste 8 Next core material

Claims (1)

A stirrer having a stirring pin that rotates around the rotation axis in a kneading space provided in the kneading pot and extends parallel to the rotation axis;
An injection piston for filling an injection mold adjacent to the kneading pot with the core paste kneaded in the kneading space,
Prior to kneading the next core material, by rotating the stirrer, at least a part of the core paste remaining on the injection mold side of the kneading space is removed from the next core. Move to the inlet side where the material is charged,
Kneading device.

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