The disclosure of Japanese Patent Application No. 2019-228939 filed on Dec. 19, 2019 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
The present disclosure relates to a core manufacturing apparatus.
There are known core manufacturing apparatuses that manufacture cores by kneading core sand along with a binder etc. in a kneading vessel and ejecting and packing the kneaded core sand (kneaded sand) into a mold. A core manufacturing apparatus developed by the present inventors kneads core sand with the kneading vessel in a horizontally lying state, as disclosed in Japanese Patent Application Publication No. 2017-131913 (JP 2017-131913 A). Since this core manufacturing apparatus ejects kneaded sand in a horizontal direction while the kneading vessel is in the horizontally lying state, it is difficult to pack the kneaded sand to the far corners of a mold.
Therefore, the present inventors developed another core manufacturing apparatus that kneads core sand with the kneading vessel in a horizontally lying state and then brings the kneading vessel into a vertically standing state to eject the kneaded sand downward and pack it into a mold, as disclosed in Japanese Patent Application Publication No. 2019-202323 (JP 2019-202323 A).
In the core manufacturing apparatuses disclosed in JP 2017-131913 A and JP 2019-202323 A, a feed port through which core sand is fed is provided on the upper side of the kneading vessel in the horizontally lying state. Although this is not clearly shown in JP 2017-131913 A and JP 2019-202323 A, a storage unit (e.g., a hopper) that stores a predetermined amount of core sand to be fed into the kneading vessel is provided above the kneading vessel and coupled to the feed port. In addition, a valve that opens and closes the feed port is provided to prevent moisture inside the kneading vessel from entering a pipe extending from the feed port to the storage unit.
The core manufacturing apparatus disclosed in JP 2019-202323 A requires keeping the storage unit in the same posture, regardless of the posture of the kneading vessel, while the kneading vessel turns from the horizontally lying state to the vertically standing state. This makes it difficult to seal the feed port of the kneading vessel by the same valve both when the kneading vessel is in the horizontally lying state and when it is in the vertically standing state.
The present disclosure provides a core manufacturing apparatus in which the feed port of the kneading vessel can be sealed by the same valve both when the kneading vessel is in a horizontally lying state and when it is in a vertically standing state.
A core manufacturing apparatus as one aspect of the present disclosure includes: a storage unit configured to store core sand; a kneading vessel, which is tubular, configured to be fed with the core sand though a feed port to which the storage unit is coupled; a kneading rod provided inside the kneading vessel so as to extend in a longitudinal direction of the kneading vessel, and configured to knead the core sand by rotating around an axis parallel to the longitudinal direction; and a piston configured to eject the kneaded core sand from one end, in the longitudinal direction, of the kneading vessel. The kneading vessel is configured to be able to transition between a horizontally lying state and a vertically standing state by turning around a first shaft. The kneading vessel is configured to be fed with the core sand in the horizontally lying state through the feed port that is located on the upper side of the kneading vessel. The piston is configured to eject the core sand downward and pack the core sand into a mold with the kneading vessel in the vertically standing state. The storage unit includes a valve that opens and closes the feed port with the kneading vessel in the horizontally lying state by turning around a second shaft parallel to the first shaft while remaining in contact with the feed port. A part of the valve has an arc shape. The storage unit is coupled to the kneading vessel so as to be turnable around the second shaft, and is configured to maintain the same posture with the valve in contact with the feed port while the kneading vessel turns.
With the above aspect, the feed port can be sealed by the same valve both when the kneading vessel is in the horizontally lying state and when it is in the vertically standing state.
In the above aspect, the core manufacturing apparatus may include a parallel linkage having a driver that has the first shaft and the second shaft as joints. With the above configuration, the core manufacturing apparatus is excellent in maintainability.
In the above aspect, the valve may be made of a resin.
In the above aspect, the valve may be in contact with the feed port of which a circumferential edge is covered with a seal member having an annular shape and made of a resin. With the above configuration, the sealing of the gap between the valve and the feed port can be improved.
In the above aspect, the valve and the seal member may be made of different resins. With the above configuration, the adhesion between the valve and the feed port can be reduced.
In the above aspect, an annular groove extending along the circumferential edge of the feed port may be provided in the resin seal member, at a side facing an outer circumferential surface of the kneading vessel.
In the above aspect, a rubber packing may be provided between the seal member and an outer circumferential surface of the kneading vessel. With the above configuration, the sealing of the gap between the valve and the feed port can be further improved.
In the above aspect, the valve may have a cut-off spherical shape obtained by cutting off a portion of the valve that does not come into contact with the feed port. With the above configuration, the size and weight of the valve can be reduced.
In the above aspect, the valve may have a spherical shape.
In the above aspect, a through-hole perpendicular to the second shaft may be formed inside the valve.
In the above aspect, the storage unit may include a hopper that stores a predetermined amount of core sand to be fed into the kneading vessel, and a weigher configured to measure the weight of the hopper. The weigher may be configured to measure the weight of the core sand stored in the hopper while the core sand is supplied to the hopper. With the above configuration, the core manufacturing apparatus is capable of simultaneously weighing and storing core sand and thereby achieves excellent productivity.
In the above aspect, the storage unit may include a preliminary tank that stores the core sand to be supplied to the hopper, and a valve provided on a pipe connecting the preliminary tank and the hopper to each other. When the core sand is supplied from the preliminary tank to the hopper, the degree of opening of the valve provided on the pipe may be adjusted based on the weight of the hopper measured by the weigher. With the above configuration, the core manufacturing apparatus can accurately control the weight of core sand to be fed into the weigh hopper.
In the above aspect, the valve configured to open and close the feed port may be made of an abrasion-resistant resin, and the seal member may be made of an abrasion-resistant resin.
With the above aspect, the present disclosure can provide a core manufacturing apparatus in which the feed port of the kneading vessel can be sealed by the same valve both when the kneading vessel is in the horizontally lying state and when it is in the vertically standing state.
Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
A specific embodiment to which the present disclosure is applied will be described in detail below with reference to the drawings. It is not intended that the present disclosure is limited to the following embodiment. To clarify the illustration, the following description and drawings are simplified as necessary.
Overall Configuration and Actions of Core Manufacturing Apparatus
First, the overall configuration and actions of a core manufacturing apparatus according to the embodiment will be described with reference to
As shown in
Here, the kneading vessel 11 is supported so as to be turnable around a shaft (first shaft) A1 by the turning support member 13 through the link L1 fixed on the kneading vessel 11. As shown in
As will be described in detail later, the posture of the storage unit 20 depends on the support member 23. As shown in
Here, the turning support member 13, the support member 23, and the links L1, L2 constitute a parallel linkage having the four shafts A1 to A4 as joints. In the example of
Thus configured, the core manufacturing apparatus according to the embodiment keeps the storage unit 20 coupled to the kneading vessel 11 in the same posture while the kneading vessel 11 turns. It is not necessary to uncouple the storage unit 20 from the kneading vessel 11 when the kneading vessel 11 turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity.
As long as the requirement that the link L1 fixed on the kneading vessel 11 should constitute a driver is met, the support member 23 may constitute a fixed link and the turning support member 13 may constitute a connector. The storage unit 20 is required to be coupled to the kneading vessel 11 so as to be turnable around the shaft A2 parallel to the turning shaft A1 of the kneading vessel 11, and to remain coupled to the kneading vessel 11 in the same posture while the kneading vessel 11 turns. As long as this requirement is met, the storage unit 20 may be kept in the same posture by connecting the shafts A1, A2 to each other by a belt or a gear instead of the parallel linkage. However, compared with the means using a belt or a gear, a parallel linkage is less likely to fail when core sand sticks thereto and is excellent in maintainability.
Detailed Configuration of Core Manufacturing Apparatus
Next, each component of the core manufacturing apparatus according to the embodiment will be described in detail with reference to
Configuration of Kneading Unit 10
The configuration of the kneading unit 10 will be described. As shown in
An ejection port 11b through which the kneaded core sand S1 is ejected is provided in one end surface, in a longitudinal direction, of the kneading vessel 11, and the piston 14 is provided on the other end surface. In the shown example, the ejection port 11b is provided so as to protrude from the end surface of the kneading vessel 11. When ejecting the core sand S1, a core forming mold (not shown) is coupled to the ejection port 11b.
The core sand S1 fed into the kneading vessel 11 is kneaded along with a binder. The core sand S1 may be either natural sand or artificial sand. The binder is, for example, an inorganic binder containing liquid glass and water, but may instead be an organic binder. The binder is sprayed from a spraying device (not shown) provided on an inner circumferential surface of the kneading vessel 11. The spraying device is provided, for example, in the vicinity of the feed port 11a.
The kneading rods 12 are provided inside the kneading vessel 11 so as to extend along substantially the entire length of the kneading vessel 11 in the longitudinal direction. There is a plurality of kneading rods 12, and these kneading rods 12 are fixed on, for example, a disc-shaped rotating base 12a. The rotating base 12a is provided inside the kneading vessel 11, at an end on the side of the piston 14, and rotates around an axis parallel to the longitudinal direction of the kneading vessel 11. Thus, the core sand S1 fed into the kneading vessel 11 is kneaded by the kneading rods 12.
The kneading rods 12 are disposed, for example, in a radial arrangement centered on a rotational axis. Alternatively, the kneading rods 12 may be disposed in an S-shape so as to be point-symmetrical with the rotational axis as the center. The shape of the kneading rods 12 is not particularly limited as long as it is a columnar shape extending parallel to the rotational axis. The cross-sectional shape of the kneading rods 12 is, for example, a circular shape, but may instead be an elliptical shape, a polygonal shape, etc.
Although this is not shown, the rotating base 12a is an external gear and driven to rotate by a driving source, such as a motor, through a gear disposed at a circumferential edge of the rotating base 12a. The operation of this driving source is controlled by, for example, the control unit 30. The rotational axis of the rotating base 12a coincides with a central axis of the cylindrical kneading vessel 11 in this embodiment, but the present disclosure is not particularly limited to this arrangement.
As described above and shown in
As shown in
As shown in
The piston 14 shown in the drawings is an electrically operated ball-screw piston, and includes a piston head 141, a piston rod 142, and a motor 143. The piston head 141 is housed inside the kneading vessel 11 and disposed closer to the ejection port 11b than the rotating base 12a is. The piston head 141 is driven by the motor 143 that is coupled to the piston head 141 through the piston rod 142 that extends through the end surface of the kneading vessel 11. The operation of the motor 143 is controlled by, for example, the control unit 30.
Except during ejection, the piston head 141 is on standby at an end of the kneading vessel 11 on the side of the piston 14. During ejection, the piston head 141 advances in the longitudinal direction of the kneading vessel 11 and ejects the kneaded core sand S1 through the ejection port 11b. As described above and shown in
A plug 11c made of rubber, for example, is mounted at a root of the ejection port 11b, i.e., on an inner end surface of the kneading vessel 11. The plug 11c can keep the core sand S1 fed into the kneading vessel 11 from leaking out of the kneading vessel 11. On the other hand, the plug 11c has an incision that has, for example, a cross shape as seen in a plan view and extends through a central portion of the plug 11c in a thickness direction thereof. Therefore, the plug 11c opens due to the incision when the core sand S1 inside the kneading vessel 11 is pressurized and ejected.
The gap between the inner circumferential surface of the kneading vessel 11 and an outer circumferential surface of the piston head 141 is kept sealed by a seal member or the like. The piston head 141 has through-holes into which the kneading rods 12 are fitted and inserted. The gap between an inner circumferential surface of each of these through-holes and an outer circumferential surface of the kneading rod 12 is also kept sealed by a seal member or the like. This configuration allows the core sand S1 inside the kneading vessel 11 to be ejected through the ejection port 11b without leaking. The piston head 141 can rotate along with the kneading rods 12. While the piston 14 is an electrically operated piston here, the piston 14 is not limited thereto and may instead be a piston driven by air pressure, oil pressure, or the like.
Configuration of Storage Unit 20
Next, the configuration of the storage unit 20 will be described. As shown in
The preliminary tank 21 is a tank that temporarily stores the core sand S1 to be supplied to the weigh hopper 22. In the shown example, an upper part of the preliminary tank 21 has a cylindrical shape and a lower part thereof has an inverted conical shape. Although this is not shown, the core sand S1 is supplied to the preliminary tank 21 from a larger storage tank through a pipe etc. The preliminary tank 21 and the weigh hopper 22 are connected to each other by the pipe P1.
The weigh hopper 22 is provided under the preliminary tank 21, and a lower portion of the preliminary tank 21 and an upper portion of the weigh hopper 22 are connected to each other by the pipe P1. The pipe P1 is provided with the valve V1. When the valve V1 is opened, the core sand S1 stored in the preliminary tank 21 is fed into the weigh hopper 22 by gravity. The amount of core sand S1 to be fed can be finely adjusted by adjusting the degree of opening of the valve V1. As will be described later in detail, the degree of opening of the valve V1 is controlled by, for example, the control unit 30.
The weigh hopper 22 stores a predetermined amount of core sand S1 that has been weighed to be fed into the kneading vessel 11. Here,
The weigh hopper 22 includes a main body 221 and a lid 222. The main body 221 has an inverted conical shape, and includes a flange 221a that is provided on an outer circumferential surface at an upper portion of the main body 221 and protrudes outward. The lid 222 is a disc-shaped cover lid and fits on an upper end portion of the main body 221. A through-hole is provided at a central portion of the lid 222, and the pipe P1 is slidably fitted in the through-hole.
The pipe P2 extends from a lower end of the main body 221. A lower end portion of the pipe P2 is slidably fitted in the pipe P3. The pipe P2 is provided with the valve V2. When the valve V2 and the valve V3 to be described later are opened, the core sand S1 stored in the weigh hopper 22 is fed into the kneading vessel 11 by gravity. As described above,
The weigher 24 is, for example, a load cell and measures the weight of the weigh hopper 22. The flange 221a of the weigh hopper 22 is placed on the weigher 24. Specifically, the weigher 24 is loaded with the weights of the weigh hopper 22 (the main body 221 and the lid 222), the core sand S1 inside the weigh hopper 22, the pipe P2, and the valve V2.
Since the pipe P1 is slidably fitted in the through-hole of the lid 222 as described above, the weigher 24 is not loaded with the weights of members located above the pipe P1. Since the pipe P2 is slidably fitted in the pipe P3, the weigher 24 is not loaded with the weights of members located under the pipe P3.
The weight of the core sand S1 fed from the preliminary tank 21 into the weigh hopper 22 can be learned from the weight measured by the weigher 24. For example, based on the weight measured by the weigher 24, the control unit 30 controls the degree of opening of the valve V1 such that the weight of the core sand S1 inside the weigh hopper 22 meets a target value. For example, the control unit 30 decreases the degree of opening of the valve V1 as the weight of the core sand S1 approaches the target value. Under this control, the weight of the core sand S1 to be fed into the weigh hopper 22 can be accurately controlled.
As shown in
A through-hole 25c through which the main body 221 of the weigh hopper 22 is inserted is provided at a central portion of the platform 25a. Thus, the weigher support member 25 supports only the weigher 24 and does not directly support the weigh hopper 22. With this configuration, the weigher 24 is able to measure the weight of the weigh hopper 22.
On the other hand, the weigher 24 supports the weigh hopper 22 while measuring the weight of the weigh hopper 22. Therefore, the weigher support member 25 supports the weigh hopper 22 through the weigher 24. The support member 23 supports the weigh hopper 22 through the weigher support member 25 and the weigher 24.
Thus, the support member 23 indirectly supports the weigh hopper 22. Similarly, the support member 23 indirectly supports the preliminary tank 21 through a support member (not shown). This is why the posture of the storage unit 20 depends on the support member 23.
Here, as shown in
As described above and shown in
Thus configured, the core manufacturing apparatus according to the embodiment keeps the storage unit 20 coupled to the kneading vessel 11 in the same posture while the kneading vessel 11 turns. It is not necessary to uncouple the storage unit 20 from the kneading vessel 11 when the kneading vessel 11 turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity.
Referring back to
The valve V3 is supported by the support member 23 shown in
As shown in
The valve V3 shown in
Here,
In the example of
In the example of
Further, in the example of
As shown in
The control unit 30 shown in
As has been described above, in the core manufacturing apparatus according to the embodiment, the storage unit 20 is coupled to the kneading vessel 11 so as to be turnable around the shaft A2, and the storage unit 20 remains coupled to the kneading vessel 11 in the same posture while the kneading vessel 11 turns. It is not necessary to uncouple the storage unit 20 from the kneading vessel 11 when the kneading vessel 11 turns. By thus eliminating the need for uncoupling and coupling actions, this apparatus achieves excellent core productivity.
In the core manufacturing apparatus according to the embodiment, the storage unit 20 includes the valve V3 having a spherical shape or a cut-off spherical shape that opens and closes the feed port 11a with the kneading vessel 11 in the horizontally lying state by turning around the shaft A2 while remaining in contact with the feed port 11a. Therefore, as shown in
The present disclosure is not limited to the above embodiment but can be changed as necessary within the scope of the gist of the disclosure.
Number | Date | Country | Kind |
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2019-228939 | Dec 2019 | JP | national |