CN114096360B

CN114096360B - Sand mould manufacturing device

Info

Publication number: CN114096360B
Application number: CN202180004481.1A
Authority: CN
Inventors: 须藤笃; 横山吉明
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 2020-04-27
Filing date: 2021-02-15
Publication date: 2023-07-21
Anticipated expiration: 2041-02-15
Also published as: CN114096360A; TWI816107B; JP6976500B1; WO2021220586A1; TW202140168A; JPWO2021220586A1

Abstract

A sand mold manufacturing apparatus (10) comprising: a blowing head (48) for retaining the wet sand and a blowing plate unit (56) arranged between the blowing head and the mould (20). The blowing plate unit includes: a sand introduction passage (86) through which wet sand blown into the mold from the blowing head by compressed air supplied to the blowing head passes; and at least one compressed air introduction passage (P1, P2) for blowing compressed air toward the wet sand blown into the mold through the sand introduction passage. An angle formed by a blowing direction (X) of the green sand from the blowing head into the mold through the sand introducing passage and blowing directions (Y1, Y2) of the compressed air toward the green sand through the at least one compressed air introducing passage is set to an acute angle.

Description

Sand mould manufacturing device

Technical Field

The present invention relates to a sand mold manufacturing apparatus, and more particularly, to a sand mold manufacturing apparatus that blows wet sand into a mold to manufacture a sand mold.

Background

For example, patent document 1 discloses a mold manufacturing apparatus for manufacturing a sand mold. The mold manufacturing apparatus disclosed in patent document 1 blows wet sand from a blowing head into a mold (core mold body) via a blowing plate to manufacture a sand mold. In this mold manufacturing apparatus, a blowing nozzle and an air sleeve for blowing out air are provided in a core sand introducing passage in a blowing plate through which blowing sand passes. The wet sand flowing in the core sand introducing passage is stirred by compressed air blown out in the horizontal direction through the blowing nozzle and the air sleeve.

CITATION LIST

Patent literature

[ patent document 1] Japanese laid-open patent publication No. 3-31047

Disclosure of Invention

Technical problem

However, the wet sand is highly viscous, and thus is poor in fillability, and thus may block a narrow flow path or the like. Therefore, in the mold manufacturing apparatus of patent document 1, when a sand mold of a complex shape is manufactured, it may be impossible to completely fill the cavity of the mold with wet sand.

The present utility model has been made in view of the above-described problems, and an object of the present utility model is to provide a sand mold manufacturing apparatus capable of properly filling a mold with wet sand when manufacturing a sand mold by blowing wet sand into the mold.

Solution to the problem

The present specification discloses a sand mold manufacturing apparatus as described below.

[ item 1]

A sand mold manufacturing apparatus for manufacturing a sand mold by blowing wet sand into a mold, the sand mold manufacturing apparatus comprising:

a blowing head for retaining the wet sand; and

a blowing plate unit disposed between the blowing head and the mold, wherein,

the blowing plate unit includes:

a sand introducing passage through which wet sand blown into the mold from the blowing head by compressed air supplied to the blowing head passes; and

at least one compressed air introduction passage for blowing compressed air toward the wet sand blown into the mold through the sand introduction passage; and is also provided with

An angle formed by a blowing direction of the green sand from the blowing head into the mold through the sand introduction passage and a blowing direction of the compressed air toward the green sand through the at least one compressed air introduction passage is set to an acute angle.

In the sand mold manufacturing apparatus according to the embodiment of the present invention, the wet sand blown from the blowing head toward the mold is blown into the mold by the compressed air blown from the compressed air introduction passage of the blow plate unit while the wet sand is stirred and finely dispersed in the sand introduction passage and in the vicinity of the opening of the mold. Since the angle formed by the blowing direction of the green sand from the blowing head into the mold through the sand introducing passage and the blowing direction of the compressed air toward the green sand through the compressed air introducing passage is set to an acute angle, the compressed air from the compressed air introducing passage functions to push the green sand into the mold from behind, thereby improving the fillability of the green sand with respect to the mold cavity.

As a result, the mold can be properly filled with the wet sand, whereby even a sand mold having a complicated shape can be properly manufactured.

[ item 2 ]

The sand mold manufacturing apparatus according to claim 1, wherein,

the sand introducing channel comprises an inlet positioned at one side close to the blowing head and an outlet positioned at one side close to the mould; and is also provided with

The aperture area of the outlet is larger than the aperture area of the inlet.

When the aperture area of the outlet of the sand introducing passage is larger than the aperture area of the inlet, the flow rate of the wet sand passing through the sand introducing passage is slower at the outlet than at the inlet. Thus, the wet sand collides with itself in the sand introducing passage to be further stirred, and is further dispersed at an outlet wider than the inlet. As a result, the wet sand has a small linear movement capability, so that the wet sand mass is less likely to adhere (stick) to the mold, and thus a mold (sand mold) having good mold release is obtained.

[ item 3 ]

a blowing head for retaining the wet sand; and

a blowing plate unit arranged between the blowing head and the mould, wherein,

the blowing plate unit includes:

at least one compressed air introduction passage for blowing compressed air toward the wet sand blown into the mold through the sand introduction passage;

The aperture area of the outlet is larger than the aperture area of the inlet.

In the sand mold manufacturing apparatus according to the embodiment of the present invention, the wet sand blown from the blowing head toward the mold is blown into the mold by the compressed air blown from the compressed air introduction passage of the blow plate unit while the wet sand is stirred and finely dispersed in the sand introduction passage and in the vicinity of the opening of the mold. Because the aperture area of the outlet of the sand introducing passage is larger than the aperture area of the inlet, the flow rate of the wet sand passing through the sand introducing passage is slower at the outlet than at the inlet. Thus, the wet sand collides with itself in the sand introducing passage to be further stirred, and is further dispersed at an outlet wider than the inlet. As a result, the green sand has a small linear movement capability, so that a large amount of green sand is less likely to adhere (stick) to the mold, and thus a molded article (sand mold) having good mold release is obtained.

[ item 4 ]

The sand mold manufacturing apparatus according to claim 2 or 3, wherein an aperture area of the outlet is larger than a sum of an aperture area of the inlet and an aperture area of the blow-out port of the at least one compressed air introduction passage.

When the aperture area of the outlet of the sand introducing passage is larger than the sum of the aperture area of the inlet and the aperture area of the blow-out port of the compressed air introducing passage, the aperture area difference of the inlet and the aperture area of the outlet can be further increased, thereby allowing the wet sand passing through the sand introducing passage to be further stirred and dispersed. Therefore, it is possible to further suppress adhesion of the wet sand mass to the mold.

[ item 5 ]

The sand mold manufacturing apparatus according to any one of the 2 nd to 4 th, wherein the wet sand includes an inorganic binder.

Generally, inorganic binders have a strong binding power. Therefore, in the case where the wet sand contains an inorganic binder, once the wet sand sticks to the mold, the sand mold becomes difficult to be ejected from the mold, so that forced attempts to eject it may cause damage to the sand mold. Because the aperture area of the outlet is larger than that of the inlet, even in the case where the green sand contains an inorganic binder, the green sand can be sufficiently stirred and dispersed, thereby allowing the green sand mass to be appropriately suppressed from adhering to the mold.

[ item 6 ]

The sand mold manufacturing apparatus according to any one of the 1 st to 5 th, wherein,

the at least one compressed air introduction passage includes a plurality of compressed air introduction passages; and is also provided with

The plurality of compressed air introduction passages are formed such that compressed air blown out from the plurality of compressed air introduction passages collide with each other.

Because compressed air is blown from the plurality of compressed air introduction passages to collide with each other, stirring and dispersion of the wet sand are further promoted. This enables a more proper filling of the mould with wet sand.

[ item 7 ]

The sand mold manufacturing apparatus according to any one of the 1 st to 6 th, wherein,

the blowing plate unit includes:

a blowing plate arranged between the blowing head and the mould, and

the bushing is hollow and columnar;

the blowing plate is provided with a communication hole, and the blowing head and the mould are communicated with each other through the communication hole; and is also provided with

The bushing is disposed in the communication hole of the blow plate and includes a sand introduction passage.

By adopting a configuration in which the blow-plate unit includes a blow plate and a hollow columnar bush provided between the blow head and the mold, it is possible to easily adapt to a desired molding condition or the kind of molded article (sand mold) to be obtained, or the like, only by replacing the bush provided in the communication hole of the blow plate.

[ item 8 ]

The sand mold manufacturing apparatus according to claim 7, wherein at least one compressed air introduction passage is formed from the blow plate to the liner.

When the compressed air introduction passage is formed from the blow plate to the liner (i.e., when the compressed air introduction passage includes a "first portion" formed in the blow plate and a "second portion" formed in the liner), the blowing direction or other conditions of the compressed air with respect to the sand introduction passage can be easily changed by exchanging the liner.

[ 9 th item ]

The sand mold manufacturing apparatus according to claim 8, wherein the blow plate unit further comprises a vent plug provided at a position of at least one compressed air introduction passage formed in the liner.

When the vent plug is provided at a portion (second portion) of the compressed air introduction passage formed in the liner, the pneumatic device can be protected from the wet sand intruded into the compressed air introduction passage.

[ item 10 ]

The sand mold manufacturing apparatus according to claim 8 or 9, wherein,

The bushing includes a groove portion formed in an annular shape at an outer periphery, the groove portion constituting a part of the plurality of compressed air introduction passages.

In the case where there are a plurality of compressed air introduction passages, when the liner includes a groove portion formed in an annular shape at the outer periphery, the groove portion constitutes a part of the plurality of compressed air introduction passages, and the compressed air can be supplied from one first portion to a plurality of second portions via the groove portion. Thus, for the plurality of second portions formed in the liner, it is not necessary to separately form the first portions in the blow plate. Thus, in the case where a plurality of sand introducing passages are provided in the blow-plate unit, this allows a plurality of bushings to be closely arranged together.

The beneficial effects of the invention are that

According to an embodiment of the present invention, there is provided a sand mold manufacturing apparatus capable of properly filling a mold with wet sand when manufacturing a sand mold by blowing wet sand into the mold.

Drawings

Fig. 1A is a sectional view schematically showing a sand mold manufacturing apparatus 10 according to an embodiment of the present invention, as viewed from the front.

Fig. 1B is a side sectional view schematically showing the sand mold manufacturing apparatus 10.

Fig. 2 is a sectional view schematically showing the main portions of the blowing head 48, the blow-plate unit 56, and the mold 20.

Fig. 3A is a top view schematically showing the bushing 60.

Fig. 3B is a sectional view schematically showing the bushing 60.

Fig. 4 is a diagram schematically showing the behavior of the wet sand.

Fig. 5A is a sectional view schematically showing a main portion of a sand mold manufacturing apparatus 10a according to another embodiment of the present invention.

Fig. 5B is a sectional view schematically showing a main portion of a sand mold manufacturing apparatus 10B according to another embodiment of the present invention.

Fig. 6A is a sectional view schematically showing a main part of a sand mold manufacturing apparatus 10c according to another embodiment of the present invention.

Fig. 6B is a sectional view schematically showing a main portion of a sand mold manufacturing apparatus 10d according to another embodiment of the present invention.

Fig. 7 is a sectional view schematically showing a main part of a sand mold manufacturing apparatus 10e according to another embodiment of the present invention.

Fig. 8A is a sectional view schematically showing a main portion of a sand mold manufacturing apparatus 10f according to another embodiment of the present invention.

Fig. 8B is a cross-sectional view taken along line F-F' in fig. 8A.

Fig. 9A is a sectional view schematically showing a main portion of a sand mold manufacturing apparatus 10g according to another embodiment of the present invention.

Fig. 9B is a sectional view taken along line G-G' in fig. 9A.

Fig. 9C is a sectional view schematically showing a bushing 60g of the sand mold manufacturing apparatus 10 g.

Fig. 10 is a sectional view showing an example of a plurality of bushings 60g closely arranged in the blow-plate unit 58 g.

Detailed Description

Hereinafter, a sand mold manufacturing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

Fig. 1A and 1B illustrate a sand mold manufacturing apparatus 10 according to an embodiment of the present invention. Fig. 1A and 1B are a sectional view of the sand mold manufacturing apparatus 10 as viewed from the front and a sectional view as viewed from the side, respectively.

The sand mold manufacturing apparatus 10 is an apparatus for manufacturing a sand mold by blowing wet sand into a mold 20. As shown in fig. 1A and 1B, the sand mold manufacturing apparatus 10 includes a blowing head 48 for retaining wet sand and a blow plate unit 56 disposed between the blowing head 48 and the mold 20.

The sand mold manufacturing apparatus 10 includes an upper frame 12 supported by a pair of support posts (not shown). The upper frame 12 extends in the left-right direction. Near the right end of the upper frame 12, a through hole 14 extending in the up-down direction is formed. The through holes 14 are provided at the pouring location.

The blowing head 48 is held by a carriage (not shown) suspended from the upper frame 12. Along the upper frame 12, the trolley reciprocates between a pouring position and a feed position to the left of the pouring position. In the feed position, the wet sand is supplied from the mixer and through a hopper (neither shown) to the blowing head 48. The wet sand contains a water-soluble inorganic binder, and may be, for example, a mixed sand containing a binder mainly composed of sodium silicate.

In the casting position, a pair of the struts 16a and 16b are disposed upright at a certain interval in the front-rear direction. For example, the struts 16a and 16b may have a prismatic shape. Near the upper portion of the struts, struts 16a and 16b are coupled together by a rotational shaft 18. A mold holding portion 22 for holding the mold 20 is mounted on the rotary shaft 18.

Cavities 24a and 24b are formed in the upper and lower portions of the mold 20, respectively. An opening 26a into one cavity 24a is formed in the upper surface of the mold 20, and an opening 26b into the other cavity 24b is formed in the lower surface of the mold 20.

In the casting position, a hollow cylindrical sleeve 28 is inserted into the through-hole 14 of the upper frame 12. An annular member 30 is mounted at the lower end of the sleeve 28. A sealing member 32 is provided on the lower surface of the annular member 30. The sleeve 28 is formed to have an increased inner diameter as it extends downward.

A cylinder 34 is mounted on the upper end of the sleeve 28. The cylinder 34 includes a cylinder block 36, an intake pipe 38, two exhaust pipes 40a and 40b, two mufflers 42a and 42b, and the like. The intake pipe 38 is connected to the surge tank 44, and air is supplied to the surge tank 44 through a pipe 46. In the pressure-adjusting tank 44, the air pressure is adjusted so that the compressed air for injecting sand is supplied from the pressure-adjusting tank 44 to the pressure cylinder 34.

The cylinder 34 moves a rod (not shown) extending from the cylinder body 36 in the up-down direction to bring the sleeve 28, the blowing head 48, and the blowing plate unit 56 into close contact with the die 20 or separate from the die 20. In other words, when sand is injected, the rod extending from the cylinder 36 descends, and pushes the sleeve 28, the blowing head 48, and the blowing plate unit 56 downward to be in close contact with the mold 20. Thereafter, when a blow valve (not shown) is opened, the compressed air in the pressure regulating tank 44 flows as blow air into the blowing head 48 through the air intake pipe 38, the cylinder 36, and the rod. After the sand is injected, the blow valve is closed so that the residual pressure in the cylinder 34 is released to the atmosphere through the exhaust pipes 40a and 40b and the silencers 42a and 42 b. Thereafter, the rod of the cylinder 34 is raised so that the sleeve 28, the blowing head 48 and the blowing plate unit 56 are separated from the die 20.

The blowing head 48 has a hollow shape and includes a head middle portion 50, a head upper portion 52, and a head lower portion 54. The head intermediate portion 50 and the head upper portion 52 communicate with respect to the die 20 in a blowing direction of the green sand (indicated by an arrow X in fig. 3B described later), and the head intermediate portion 50 and the head lower portion 54 also communicate in the same direction.

The head intermediate portion 50 is formed in a hollow cylindrical shape. In addition, the head intermediate portion 50 is formed to have a substantially constant inner diameter. The head upper portion 52 is formed in a hollow cylindrical shape. The head upper portion 52 is formed to have an increased inner diameter as it extends from top to bottom. At the boundary of the upper head portion 52 and the middle head portion 50, their inner surfaces are continuous. The head lower portion 54 is formed in a hollow columnar shape. At the boundary of the lower head portion 54 and the intermediate head portion 50, their inner surfaces are continuous. The head lower portion 54 is formed as: as shown in fig. 1A, the wider the lower the front view, and as shown in fig. 1B, the narrower the lower the side view. In each of the head intermediate portion 50, the head upper portion 52, and the head lower portion 54, a cooling path that allows the coolant to flow may be formed. As the coolant, for example, water, oil, ethylene glycol, or the like can be used.

The blow-plate unit 56 is disposed to cover the lower surface of the blow head 48. In the casting position, the blow-plate unit 56 is located between the blow head 48 and the mold 20.

Referring to fig. 2, the construction of the blow-plate unit 56 will be described in more detail. Fig. 2 is a sectional view schematically showing the main portions of the blowing head 48, the blow-plate unit 56, and the mold 20.

As shown in fig. 2, the blow-plate unit 56 includes a rectangular plate-shaped blow plate 58 and a hollow columnar bush 60. A blow plate 58 is provided on the lower surface of the blow head 48 and is located between the blow head 48 and the mold 20 at the casting position. In the central portion of the blow plate 58, the blow plate 58 has a communication hole 62, through which the blowing head 48 and the die 20 communicate with each other. The communication hole 62 is formed in a substantially cylindrical shape, having an enlarged diameter portion 62a at an upper end. The shape and the inner diameter of the communication hole 62 are substantially the same as the outer shape and the outer diameter of the bush 60. Accordingly, when the bushing 60 is fitted in the communication hole 62, the upper surface of the blow plate 58 and the upper surface of the bushing 60 are flush with each other, and the lower surface of the blow plate 58 and the lower surface of the bushing 60 are flush with each other.

In addition, the blow plate 58 includes first passage portions 64a and 64b and second passage portions 66a and 66b through which compressed air passes. Inside the blow plate 58, first passage portions 64a and 64b and second passage portions 66a and 66b are formed slightly upward in the up-down direction.

The first passage portions 64a and 64b are formed to extend from one side surface (left side surface in this example) of the blow plate 58 in the right direction within the blow plate 58. The first passage portions 64a and 64b are formed substantially parallel to each other with the communication hole 62 interposed therebetween. The second passage portion 66a extends from near the right end of the first passage portion 64a to the rear of the first passage portion 64a at a right angle, thereby allowing the first passage portion 64a to communicate with the communication hole 62. The second passage portion 66b extends at right angles from near the right end of the first passage portion 64b to the front of the first passage portion 64b, thereby allowing the first passage portion 64b to communicate with the communication hole 62. Thus, in plan view, the first channel portion 64a and the second channel portion 66a form the channel into a substantially L-shape, and the first channel portion 64b and the second channel portion 66b form the channel into a substantially L-shape such that the second channel portions 66a and 66b lie on the same straight line. As shown in fig. 1A, an intake pipe 68 is connected to one end (left end) of each of the first passage portions 64a and 64 b. The two air inlet pipes 68 are coupled to a single air inlet pipe 72 via a joint 70. The intake pipe 72 is connected to a pressure regulating portion 74 having a valve. Air is supplied to the pressure regulating portion 74 through a duct 76. In the pressure adjusting portion 74, the pressure of the air is adjusted so that the compressed air is supplied from the pressure adjusting portion 74 into the blow plate 58.

Inside the blow plate 58, a cooling path 78 that allows the coolant to flow is formed. The cooling path 78 has a substantially U-shape in plan view. On the lower surface of the blow plate 58, an annular groove 80 is formed so as to surround the communication hole 62. The sealing member 82 is fitted in the groove 80.

Referring also to fig. 3A and 3B, a specific configuration of the bushing 60 will be described. Fig. 3A is a top view schematically showing the bushing 60, and fig. 3B is a cross-sectional view schematically showing the bushing 60.

The liner 60 includes a flange portion 84 provided at an upper end thereof and a sand introduction passage 86 extending in the entire up-down direction. The sand introducing passage 86 includes: an inlet 88 located on a side adjacent the blowing head 48; an outlet 90 located on a side adjacent to the die 20; an expanded diameter portion 92 having an inner diameter that increases as it extends downwardly from the inlet 88; and an equal diameter portion 93 formed below the expanded diameter portion 92 and having the same inner diameter. Further, the liner 60 includes third passage portions 94a and 94b, and the second passage portions 66a and 66b of the blow plate 58 and the sand introducing passage 86 communicate with each other through the third passage portions 94a and 94 b. The third passage portions 94a and 94b are formed such that the compressed air blown from the third passage portions 94a and 94b to the sand introducing passage 86 collide with each other. In the side view, as shown in fig. 3B, the third passage portions 94a and 94B extend obliquely downward toward the sand introducing passage 86. In plan view, as shown in fig. 3A, the third passage portions 94a and 94b are substantially on the same straight line.

As shown in fig. 2, the first passage portion 64a, the second passage portion 66a, and the third passage portion 94a define a compressed air introduction passage P1; similarly, the first, second and third passage portions 64b, 66b and 94b define a compressed air introduction passage P2. In other words, the compressed air introduction passages P1 and P2 are formed from the blow plate 58 to the liner 60. Thus, the blow-plate unit 56 includes: a sand introducing passage 86 through which the wet sand blown from the blowing head 48 to the mold 20 by the compressed air supplied to the blowing head 48 passes through the sand introducing passage 86; and compressed air introduction passages P1 and P2 that blow compressed air toward the wet sand blown into the mold 20 through the sand introduction passage 86. The compressed air introduction passages P1 and P2 are formed such that the compressed air blown out from the compressed air introduction passages P1 and P2 collide with each other.

As shown in fig. 3B, an angle D1 formed by the blowing direction X of the green sand entering the mold 20 from the blowing head 48 through the sand introducing passage 86 and the blowing direction Y1 of the compressed air toward the green sand through the third passage portion 94a (compressed air introducing passage P1) is set to an acute angle (i.e., D1 is greater than 0 ° and less than 90 °). Similarly, an angle D2 formed by the blowing direction X and the blowing direction Y2 of the compressed air toward the wet sand through the third passage portion 94b (compressed air introduction passage P2) is set to an acute angle (i.e., D2 is greater than 0 ° and less than 90 °). In the illustrated example, the blowing direction X is downward (vertically downward), and the angles D1 and D2 are each set to about 30 °.

In the bushing 60, the aperture area Ao of the outlet 90 is larger than the aperture area Ai of the inlet 88. In addition, the aperture area Ao of the outlet 90 is larger than the sum of the aperture area Ai of the inlet 88 and the aperture areas Aa and Ab of the respective blowout ports 95a and 95b of the third passage portions 94a and 94b (the compressed air introduction passages P1 and P2). However, the aperture area Ao of the outlet 90 is preferably less than three times the sum.

In the bushing 60, the inlet 88 has a diameter a of, for example, 5mm or more. The expanded diameter portion 92 has an angle B equal to or greater than 0 ° but less than 180 °. The third passage portions 94a and 94b have a caliber C of, for example, 1mm or more. The diameter E of the outlet 90 is greater than the diameter A of the inlet 88. Any corner portions of the sand introduction passage 86 of the liner 60 are preferably smooth.

For example, the bushing 60 is made of a metal material or a fluoroplastic such as PTFE. When the liner 60 is made of fluoroplastic, the wet sand can be suppressed from sticking to the liner 60.

Next, the operation of the sand mold manufacturing apparatus 10 will be described.

As shown in fig. 1A and 1B, in the casting position, the blowing head 48 and the blowing plate unit 56 are located between the sleeve 28 and the mold 20. The rod of the pressure cylinder 34 pushes the sleeve 28 downward so that the lower surface of the sleeve 28 is connected to the upper head 52 of the blowing head 48 via the annular member 30 and the sealing member 32; in addition, the sleeve 28, the blowing head 48, and the blowing plate unit 56 are pushed downward to be in close contact with the mold 20. After that, as the blow valve opens, the compressed air in the pressure regulating tank 44 is blown as blowing air to the blowing head 48 via the pressure cylinder 34. As a result, the wet sand in the blowing head 48 passes through the sand introducing passage 86 of the blow plate unit 56, and is thereby supplied into the cavity 24a of the mold 20. At this time, for the wet sand that passes through the sand introducing passage 86 and is blown into the mold 20, compressed air is blown from the compressed air introducing passages P1 and P2 of the blow-plate unit 56.

Now, with reference to fig. 4, the behavior of the wet sand will be described. In fig. 4, the blank arrows indicate how the green sand mass tapers.

First, since the flow path of the green sand is expanded by the expanded diameter portion 92 of the liner 60, the green sand that has been pushed from the blowing head 48 to the sand introducing passage 86 of the liner 60 by the compressed air is dispersed into small pieces while being diffused.

At about the same time as the wet sand is blown from the blowing head 48 to the sand introducing passage 86 of the liner 60, the compressed air is blown from the compressed air introducing passages P1 and P2 of the blow-plate unit 56 to the sand introducing passage 86 of the liner 60 in the directions indicated by arrows Y1 and Y2. As a result, the wet sand is stirred and becomes finer agglomerates or sand grains, which are poured into the mold 20.

After the sand is injected, the blow valve is closed so that the residual pressure in the cylinder 34 is released to the atmosphere through the exhaust pipes 40a and 40b and the silencers 42a and 42 b. Thereafter, the rod of the pressure cylinder 34 is raised, whereby the sleeve 28, the blowing head 48 and the blowing plate unit 56 become separated from the die 20, and further, the connection between the head upper portion 52 of the blowing head 48 and any member above it (for example, the sleeve 28) is released. Then, the blowing head 48 and the blowing plate unit 56 are temporarily retracted from the pouring position by the carriage, and the rotary shaft 18 is rotated to invert the mold 20. As a result, cavity 24a is at the bottom and cavity 24b is at the top.

The blowing head 48 and the blowing plate unit 56 are then moved again by the trolley to the pouring position. In the casting position, a similar operation to that described above is performed to perform a sand casting operation to the cavity 24b of the mold 20. Thereafter, by the carriage, the blowing head 48 and the blowing plate unit 56 are retracted from the pouring position, and the sand mold as the molded article is removed from the cavities 24a and 24b of the mold 20 in the pouring position.

The above operation is repeated as many times as necessary.

In the sand mold manufacturing apparatus 10 according to one embodiment of the present invention, the wet sand blown from the blowing head 48 toward the mold 20 is blown into the mold 20 while being stirred and finely dispersed in the sand introducing passage 86 and in the vicinity of the opening 26a (26 b) of the mold 20 by the compressed air blown from the compressed air introducing passages P1 and P2 of the blow-plate unit 56. Since the angles D1 and D2 formed by the blowing direction X of the green sand from the blowing head 48 into the mold 20 through the sand introducing passage 86 and the blowing directions Y1 and Y2 of the compressed air toward the green sand through the compressed air introducing passages P1 and P2 are set to acute angles, the compressed air from the compressed air introducing passages P1 and P2 functions to push the green sand into the mold 20 from behind, thereby improving the fillability of the green sand with respect to the cavity 24a (24 b) of the mold 20. As a result, the mold 20 can be properly filled with the wet sand, whereby even a sand mold having a complicated shape can be properly manufactured. In the sand mold manufacturing apparatus 10 according to one embodiment of the present invention, even if the pressure of the compressed air blown out from the compressed air introduction passages P1 and P2 and the pressure of the compressed air supplied to the blowing head 48 are relatively low pressures (for example, about 0.3 MPa), the mold 20 can be properly filled with wet sand.

Further, in the sand mold manufacturing apparatus 10 according to one embodiment of the present invention, the aperture area Ao of the outlet 90 of the sand introducing passage 86 is larger than the aperture area Ai of the inlet 88 (i.e., the flow path expands), so that the flow rate of the wet sand passing through the sand introducing passage 86 is slower at the outlet 90 than at the inlet 86. Thus, the wet sand collides with itself in the sand introducing passage 86 to be further stirred, and is further dispersed at the outlet 90 wider than the inlet 88. As a result, the wet sand has less linear movement ability, so that the wet sand mass is less likely to adhere (stick) to the mold 20, and thus a molded article (sand mold) having good mold release properties is obtained.

When the aperture area Ao of the outlet 90 of the sand introducing passage 86 is larger than the sum of the aperture area Ai of the inlet 88 and the aperture areas Aa and Ab of the blowout ports 95a and 95b of the compressed air introducing passages P1 and P2, respectively, the difference between the aperture area Ai of the inlet 88 and the aperture area Ao of the outlet 90 can be further increased, thereby allowing the wet sand passing through the sand introducing passage 86 to be further stirred and dispersed. Therefore, it is possible to further suppress the adhesion of the wet sand mass to the mold 20.

Generally, inorganic binders have a strong binding power. Therefore, in the case where the wet sand contains an inorganic binder, if the wet sand sticks to the mold 20, the sand mold becomes difficult to be ejected from the mold 20, so that forced attempts to eject it may cause damage to the sand mold. Because the aperture area Ao of the outlet 90 is larger than the aperture area Ai of the inlet 88, even in the case where the green sand contains an inorganic binder, the green sand can be sufficiently stirred and dispersed, thereby allowing the green sand mass to be appropriately suppressed from adhering to the mold 20.

As shown in the drawing, in the case where the blow-plate unit 56 includes a plurality of compressed air introduction passages P1 and P2, compressed air is blown from the plurality of compressed air introduction passages P1 and P2 to collide with each other, thereby further promoting the stirring and dispersion of the wet sand. This enables the mold 20 to be filled with wet sand more appropriately.

By adopting a configuration in which the blow-plate unit 56 includes the blow-plate 58 and the hollow columnar bush 60 provided between the blow head 48 and the mold 20, it is possible to easily adapt to a desired molding condition or the kind of molded article (sand mold) to be obtained, or the like, only by replacing the bush 60 provided in the communication hole of the blow-plate 58.

Further, when the compressed air introduction passages P1 and P2 are formed from the blow plate 58 to the liner 60, that is, when the compressed air introduction passages P1 and P2 include "first portions" (specifically, the first passage portions 64a and 64b and the second passage portions 66a and 66 b) formed in the blow plate 58 and "second portions" (specifically, the third passage portions 94a and 94 b) formed in the liner 60, the blowing direction or other conditions of the compressed air with respect to the sand introduction passage 86 can be easily changed by replacing the liner 60.

Fig. 5A shows a sand mould manufacturing apparatus 10a according to another embodiment of the present invention. The sand mold manufacturing apparatus 10a shown in fig. 5A may be regarded as a "short sleeve type" and includes a blow plate unit 56a instead of the blow plate unit 56 of the sand mold manufacturing apparatus 10 shown in fig. 2 and the like.

The blow-plate unit 56a includes a rectangular plate-shaped blow-plate 58a and a hollow cylindrical bushing 96. In the central portion of the blow plate 58a, the blow plate 58a has a communication hole 98, through which the blowing head 48 and the die 20 communicate with each other. The communication hole 98 is formed in a substantially cylindrical shape, and has an enlarged diameter portion 98a at an upper end of the communication hole 98. The enlarged diameter portion 98a of the communication hole 98 has substantially the same shape and inner diameter as the outer shape and outer diameter of the bushing 96, and the bushing 96 is to be fitted into the enlarged diameter portion 98a.

Further, the blow plate 58a includes compressed air introduction passages P3 and P4. The compressed air introduction passage P3 is composed of a first passage portion 64a and a second passage portion 100a, the first passage portion 64a being similar to the passage portion of the blow plate 58. The compressed air introduction passage P4 is composed of a first passage portion 64b and a second passage portion 100b, the first passage portion 64b being similar to the passage portion of the blow plate 58.

The second passage portion 100a extends downward from near the right end of the first passage portion 64a obliquely rearward at right angles to the first passage portion 64a such that the first passage portion 64a and the communication hole 98 communicate through the second passage portion 100 a. The second passage portion 100b extends downward from near the right end of the first passage portion 64b obliquely forward at right angles to the first passage portion 64b, so that the first passage portion 64b and the communication hole 98 communicate through the second passage portion 100 b. Therefore, in a side view, the second passage portions 100a and 100b extend obliquely downward toward the communication hole 98. The first passage portion 64a and the second passage portion 100a define the compressed air introduction passage P3 in a substantially L-shape in plan view; the first passage portion 64b and the second passage portion 100b define the compressed air introduction passage P4 in a substantially L shape; and the second channel portions 100a and 100b are substantially collinear. The second passage portions 100a and 100b are formed such that the compressed air blown from the second passage portions 100a and 100b to the communication hole 98 (sand introducing passage) collides with each other. In other words, the compressed air introduction passages P3 and P4 are formed such that the compressed air blown out from the compressed air introduction passages P3 and P4 collide with each other.

In addition, inside the blow plate 58a, the cooling path 102 is formed in a substantially U-shape that allows the coolant to flow. Further, similar to the blow plate 58, an annular groove 80 is formed on the lower surface of the blow plate 58a so as to surround the communication hole 98, and the seal member 82 is fitted in the groove 80.

The bushing 96 is formed shorter than the bushing 60 of the sand mold manufacturing apparatus 10. The bushing 96 includes a flange portion 104 provided at an upper end thereof and a through hole 106 extending in the entire up-down direction. The through hole 106 includes: an inlet 108 located on a side closer to the blowing head 48; and an expanded diameter portion 110 that expands downwardly from the inlet 108. The bushing 96 is fitted in the enlarged diameter portion 98a of the communication hole 98 such that the upper surface of the bushing 96 and the upper surface of the blow plate 58a are flush with each other. The communication hole 98 and the through hole 106 in which the bushing 96 is fitted in the enlarged diameter portion 98a define a sand introducing passage corresponding to the sand introducing passage 86 of the sand mold manufacturing apparatus 10.

Other structural aspects of the sand mold manufacturing apparatus 10a are similar to those of the sand mold manufacturing apparatus 10, and any repetitive description thereof will be omitted. In the sand mold manufacturing apparatus 10a, effects similar to those of the sand mold manufacturing apparatus 10 can also be obtained.

Fig. 5B shows a sand mold manufacturing apparatus 10B according to yet another embodiment of the present invention. The sand mold manufacturing apparatus 10B shown in fig. 5B may be considered "linerless" and includes a blow plate unit 56B in place of the blow plate unit 56a of the sand mold manufacturing apparatus 10a shown in fig. 5A.

The blow-plate unit 56b differs from the blow-plate unit 56a in that the blow-plate unit 56b has no bushings. In other words, in the blow-plate unit 56b, a portion corresponding to the bushing 96 of the blow-plate unit 56a is formed as a single piece portion of the blow-plate unit 56 b. Accordingly, the sand introducing passage 86b of the sand mold manufacturing apparatus 10b is defined by the communication hole in the blow plate unit 56 b. Other structural aspects of the blow-plate unit 56b are similar to those of the blow-plate unit 56a, and any repetitive description thereof will be omitted. In the sand mold manufacturing apparatus 10b, effects similar to those of the sand mold manufacturing apparatus 10a can also be obtained.

Fig. 6A shows a sand mould manufacturing apparatus 10c according to yet another embodiment of the present invention. The sand mold manufacturing apparatus 10c shown in fig. 6A may be regarded as "directly blown to an opening type", and includes a blow plate unit 56c instead of the blow plate unit 56 of the sand mold manufacturing apparatus 10 shown in fig. 2 and the like. In this embodiment, a different mold 20c from the mold 20 shown in fig. 2 and the like is used.

The blow-plate unit 56c is formed in a rectangular plate shape thinner than the blow-plate unit 56. In a central portion of the blow-plate unit 56c, the blow-plate unit 56c includes a sand introducing passage 86c. The sand introducing passage 86c is defined by a communication hole through which the blowing head 48 and the mold 20c communicate with each other. The sand introducing passage 86c includes: an inlet 112 located on a side closer to the blowing head 48; and an expanded diameter portion 114 that expands downwardly from the inlet 112. The depth (i.e., the dimension in the up-down direction) of the opening 116 of the die 20c is set to be larger than the opening 26a of the die 20.

In the sand mold manufacturing apparatus 10c, compressed air introduction passages P5 and P6 are formed from the blow plate unit 56c to the mold 20c. The compressed air introduction passage P5 is defined by a first passage portion 118a and a second passage portion 120a formed in the blow-plate unit 56c and a third passage portion 122a formed in the die 20c. Similarly, the compressed air introduction passage P6 is defined by a first passage portion 118b and a second passage portion 120b formed in the blow-plate unit 56c and a third passage portion 122b formed in the die 20c.

The first passage portions 118a and 118b are formed to extend from one side face (left side face in the present embodiment) of the blow-plate unit 56c in the right direction within the blow-plate unit 56 c. The first passage portions 118a and 118b are formed parallel to each other with the sand introducing passage 86c interposed therebetween. The second passage portion 120a extends downward from near the right end of the first passage portion 118a obliquely rearward at right angles to the first passage portion 118a and is exposed on the lower surface of the blow-plate unit 56 c. The second passage portion 120b extends downward from near the right end of the first passage portion 118b obliquely forward at right angles to the first passage portion 118b and is exposed on the lower surface of the blow-plate unit 56 c.

The third passage portion 122a of the die 20c is formed to allow the second passage portion 120a and the opening 116 to communicate and is located on the extended portion of the second passage portion 120a while keeping the blow-plate unit 56c pressed against the die 20 c. Similarly, the third passage portion 122b of the die 20c is formed to allow the second passage portion 120b and the opening 116 to communicate and to be located on the extended portion of the second passage portion 120b while keeping the blow-plate unit 56c pressed against the die 20 c.

Accordingly, as shown in fig. 6A, the second passage portions 120a and 120b and the third passage portions 122a and 122b extend obliquely downward toward the opening 116 in side view while keeping the blow-plate unit 56c pressed against the die 20 c. The first, second and third passage portions 118a, 120a and 122a define the compressed air introduction passage P5 in a substantially L-shape in plan view; the first, second and third passage portions 118b, 120b and 122b define the compressed air introduction passage P6 to be substantially L-shaped; and the second channel portions 120a and 122a are substantially collinear with the third channel portions 120b and 122 b. The third passage portions 122a and 122b are formed such that the compressed air blown from the third passage portions 122a and 122b to the opening 116 collide with each other. In other words, the compressed air introduction passages P5 and P6 are formed such that the compressed air blown out from the compressed air introduction passages P5 and P6 collide with each other. Similar to that shown in fig. 1A, the intake pipe 68 is connected to one end (left end) of each of the passage portions 118a and 118 b.

In addition, inside the blow-plate unit 56c, the cooling path 124 is formed in a substantially U-shape that allows the coolant to flow. Further, an annular groove 126 is formed on the lower surface of the blow-plate unit 56c to surround the sand introducing passage 86c, and a sealing member 128 is fitted in the groove 126. On the upper surface of the mold 20c, an annular groove 130 is formed at a position corresponding to the groove 126. Accordingly, while keeping the blow-plate unit 56c pressed against the mold 20c, the sealing member 128 is fitted in the groove 126 and the groove 130, thereby sealing the gap between the blow-plate unit 56c and the mold 20 c.

Other structural aspects of the sand mold manufacturing apparatus 10c are similar to those of the sand mold manufacturing apparatus 10, and any repetitive description thereof will be omitted. In the sand mold manufacturing apparatus 10c, effects similar to those of the sand mold manufacturing apparatus 10 can also be obtained.

Fig. 6B shows a sand mould manufacturing apparatus 10d according to yet another embodiment of the present invention. The sand mold manufacturing apparatus 10d shown in fig. 6B may be regarded as a "direct blow surface type" and includes a blow plate unit 56d instead of the blow plate unit 56c of the sand mold manufacturing apparatus 10c shown in fig. 6A. In the present embodiment, a mold 20d different from the mold 20c shown in fig. 6A is used.

The blow-plate unit 56d includes second channel portions 132a and 132b that are different from the second channel portions 120a and 120b of the blow-plate unit 56 c. Further, the mold 20d includes third channel portions 134a and 134b that are different from the third channel portions 122a and 122b of the mold 20 c. Accordingly, the sand mold manufacturing apparatus 10d includes compressed air introduction passages P7 and P8 that are different from the compressed air introduction passages P5 and P6 of the sand mold manufacturing apparatus 10 c.

The compressed air introduction passage P7 is defined by the first passage portion 118a, the second passage portion 132a, and the third passage portion 134a, and the compressed air introduction passage P8 is defined by the first passage portion 118b, the second passage portion 132b, and the third passage portion 134b. The second passage portion 132a extends downward from near the right end of the first passage portion 118a at right angles to the first passage portion 118a and is exposed on the lower surface of the blow-plate unit 56 d. The second passage portion 132b extends downward from near the right end of the first passage portion 118b at right angles to the first passage portion 118b and is exposed on the lower surface of the blow-plate unit 56 d.

A third passage portion 134a is formed on the upper surface of the die 20d to allow the second passage portion 132a and the opening 116 to communicate while keeping the blow-plate unit 56d pressed against the die 20 d. Similarly, a third passage portion 134b is formed on the upper surface of the die 20d to allow the second passage portion 132b and the opening 116 to communicate while keeping the blow-plate unit 56d pressed against the die 20 d.

Accordingly, as shown in fig. 6B, while keeping the blow-plate unit 56d pressed against the die 20d, the third passage portions 134a and 134B extend obliquely downward toward the opening 116 in side view. In other words, the third passage portions 134a and 134b are expanded obliquely downward toward the opening 116. In a plan view, a substantially L-shaped compressed air introduction passage P7 is defined by the first passage portion 118a, the second passage portion 132a, and the third passage portion 134 a; a substantially L-shaped compressed air introduction passage P8 is defined by the first passage portion 118b, the second passage portion 132b, and the third passage portion 134 b; and the third channel portions 134a and 134b are substantially collinear. The third passage portions 134a and 134b are formed such that the compressed air blown from the third passage portions 134a and 134b to the opening 116 collide with each other. In other words, the compressed air introduction passages P7 and P8 are formed such that the compressed air blown out from the compressed air introduction passages P7 and P8 collide with each other.

Other structural aspects of the sand mold manufacturing apparatus 10d are similar to those of the sand mold manufacturing apparatus 10, and any repetitive description thereof will be omitted. In the sand mold manufacturing apparatus 10d, effects similar to those of the sand mold manufacturing apparatus 10c can be obtained.

Fig. 7 shows a sand mold manufacturing apparatus 10e according to yet another embodiment of the present invention. In the present embodiment, a mold 20e different from the mold 20 shown in fig. 2 or the like is used.

The die 20e has an opening 136 that is different from the opening 26a of the die 20. The aperture area of opening 136 is smaller than the aperture area of opening 26 a. The aperture area of the opening 136 may be about 1/4 of the aperture area Ao of the outlet 90 of the bushing 60.

Other structural aspects of the sand mold manufacturing apparatus 10e are similar to those of the sand mold manufacturing apparatus 10, and any repetitive description thereof will be omitted. In the sand mold manufacturing apparatus 10e, effects similar to those of the sand mold manufacturing apparatus 10 can also be obtained.

Although an example in which the blow-plate unit includes two compressed air introduction passages is shown, the number of compressed air introduction passages is not limited to two. Only one compressed air introduction passage may be provided in the blow-plate unit, or three or more compressed air introduction passages may be provided. However, the number of compressed air introduction passages is preferably two or more.

Fig. 8A and 8B illustrate a sand mold manufacturing apparatus 10f according to yet another embodiment of the present invention. Fig. 8A is a sectional view schematically showing a main part of the sand mold manufacturing apparatus 10F, and fig. 8B is a sectional view taken along a line F-F' of fig. 8A. The sand mold manufacturing apparatus 10f shown in fig. 8A and 8B includes a blow plate unit 56f instead of the blow plate unit 56 of the sand mold manufacturing apparatus 10 shown in fig. 2 and the like.

The blow-plate unit 56f includes a rectangular plate-like blow-plate 58f and a hollow cylindrical bush 60f. The blow plate 58f includes a groove portion 138 and a channel portion 140 in place of the first channel portions 64a and 64b and the second channel portions 66a and 66b of the blow plate 58. The bushing 60f differs from the bushing 60 in that the bushing 60f includes four channel portions 94a, 94b, 94c, and 94d.

In the communication hole 62 of the blow plate 58f, the groove portion 138 is formed in a ring shape at a position corresponding to the outer openings of the passage portions 94a to 94d of the bush 60f. The channel portion 140 is formed in a straight line shape to allow the groove portion 138 to communicate with the front face of the blow plate 58 f. At one end of the channel portion 140, as in the sand mold manufacturing apparatus 10 shown in fig. 2, an air intake pipe 68 shown in fig. 1A is connected. The air inlet pipe 68 is coupled to an air inlet pipe 72 via a joint 70. The four channel portions 94a to 94d of the bushing 60f are disposed at substantially equal intervals. The passage portions 94a to 94d are formed such that the compressed air blown from the passage portions 94a to 94d to the sand introducing passage 86 collide with each other. The bushing 60f is positioned such that none of the channel portions 94 a-94 d are located on an extension of the channel portion 140 of the blow plate 58 f. In the sand mold manufacturing apparatus 10f, the passage portions 94a to 94d of the liner 60 and the passage portion 140 and the groove portion 138 of the blow plate 58f define a compressed air introduction passage.

Other structural aspects of the sand mold manufacturing apparatus 10f are similar to those of the sand mold manufacturing apparatus 10, and any repetitive description thereof will be omitted.

In the sand mold manufacturing apparatus 10f, compressed air is supplied into the blow plate 58f through the air intake pipe 68. The compressed air passes through the passage portion 140, bypasses the outer periphery of the liner 60f via the groove portion 138, and flows from the respective passage portions 94a to 94d into the sand introducing passage 86 in the liner 60 f.

In the sand mold manufacturing apparatus 10f, effects similar to those of the sand mold manufacturing apparatus 10 can also be obtained.

In addition, in the liner used in the sand mold manufacturing apparatus 10f, two or more passage portions may be formed so that the compressed air blown from each passage portion to the sand introducing passage 86 collides with each other.

Referring to fig. 9A, 9B and 9C, a sand mold manufacturing apparatus 10g according to still another embodiment of the present invention will be described. Fig. 9A is a sectional view schematically showing a main portion of the sand mold manufacturing apparatus 10G, and fig. 9B is a sectional view taken along a line G-G' of fig. 9A. Fig. 9C is a sectional view schematically showing a bushing 60g of the sand mold manufacturing apparatus 10g.

The sand mold manufacturing apparatus 10g shown in fig. 9A, 9B, and 9C includes a blow plate unit 56g instead of the blow plate unit 56f of the sand mold manufacturing apparatus 10f shown in fig. 8A and the like.

The blow-plate unit 56g includes a rectangular plate-shaped blow-plate 58g and a hollow cylindrical bush 60g. The blow plate 58g includes a channel portion 140. Bushing 60g includes a channel portion 142 and channel portions 144a and 144b.

The groove portion 142 of the bush 60g is formed in a ring shape at the outer periphery of the bush 60g. The channel portion 140 of the blow plate 58g is formed in a straight line shape to allow the groove portion 142 to communicate with the front face of the blow plate 58 g. The channel portion 142 allows the channel portion 140 of the blow plate 58g to communicate with the channel portions 144a and 144b of the bushing 60g. The passage portions 144a and 144b of the liner 60g are formed such that the compressed air blown from the passage portions 144a and 144b to the sand introducing passage 86g collide with each other.

The sand introducing passage 86g includes an inlet 88 on the side close to the blowing head 48, an outlet 90 on the side close to the die 20, an equal diameter portion 93 extending downward from the inlet 88 and having the same inner diameter, and an expanded diameter portion 92 expanding downward from the equal diameter portion 93.

In the sand mold manufacturing apparatus 10g, the channel portion 140 of the blow plate 58g and the groove portion 142 and the channel portions 144a and 144b of the liner 60g define a plurality of compressed air introduction channels. Thus, the groove portion 142 of the liner 60g constitutes a part of these compressed air introduction passages.

As shown in fig. 9C, the blow-plate unit 56g includes the vent plugs 59 provided for the passage portions 144a and 144b of the liner 60g, respectively (i.e., the positions of the compressed air introduction passages formed in the liner 60 g).

As shown in the present embodiment, when the vent plug 59 is provided at a portion of the compressed air introduction passage formed in the liner 60g, the pneumatic device can be protected from the wet sand intruded into the compressed air introduction passage.

One technique for protecting the pneumatic device from the wet sand that invades the compressed air-introducing passage may be to wind a filter (e.g., a wire mesh) around the outer periphery of the liner. However, under this technique, when the liner is mounted to the blow plate, the filter may be dislocated, thereby reducing operability. On the other hand, when the vent plug 59 as shown in the drawing is used, such a problem does not occur.

In addition, in the present embodiment, the bush 60g includes a groove portion 142 formed in an annular shape at the outer periphery, the groove portion 142 constituting a part of the plurality of compressed air introduction passages. As a result, the compressed air may be supplied from one "first portion" (i.e., a portion formed in the blow plate 58 g) of the compressed air introduction passage to a plurality of "second portions" (i.e., portions formed in the liner 60 g) via the groove portions. Thus, for the plurality of second portions formed in the liner 60g, it is not necessary to separately form the first portions in the blow plate 58 g. Thus, as shown in fig. 10, in the case where a plurality of sand introducing passages 86g are provided in the blow-plate unit 58g, this allows a plurality of bushings 60g to be closely arranged together. On the other hand, as shown in the sand mold manufacturing apparatus 10f of fig. 8A and the like, the groove portion 138 may be provided in the blow plate 58 f; however, in this case, when a plurality of sand introducing passages 86g are provided, each sand introducing passage 86g requires a space for the groove portion 138, which makes it difficult to closely arrange the plurality of bushings 60f together. Note that the number and arrangement of the plurality of bushings 60g (i.e., the number and arrangement of the plurality of sand introducing passages 86) are not limited to the example shown in fig. 10.

In the above embodiment, the blowing direction X is downward (vertical direction); however, this is not a limitation. The blowing direction X may be inclined downward.

In the above embodiment, the bushing includes the expanded diameter portion 92 and the constant diameter portion 93; however, this is not a limitation. In the liner, an expanded diameter portion having an increased inner diameter may be formed all the way from the inlet 88 to the outlet 90. Further, the bushing may be formed in a rectangular columnar shape.

The blow-out port of the compressed air introduction passage (i.e., the end portion closer to the sand introduction passage) may be provided at the equal diameter portion of the sand introduction passage or at the expanded diameter portion of the sand introduction passage.

The blowing head and the blowing plate unit may be formed monolithically. The blow-plate unit and the mold may be formed monolithically.

As described above, the sand mold manufacturing apparatus 10 according to an embodiment of the present invention is a sand mold manufacturing apparatus that manufactures a sand mold by blowing wet sand into a mold 20, including: a blowing head 48 for retaining the wet sand; and a blow-plate unit 56 disposed between the blow head 48 and the mold 20. The blow-plate unit 56 includes: a sand introducing passage 86 through which the wet sand blown from the blowing head 48 to the mold 20 by the compressed air supplied to the blowing head 48 passes through the sand introducing passage 86; and at least one compressed air introduction passage P1 (P2) for blowing compressed air toward the wet sand blown into the mold 20 through the sand introduction passage 86. The angle D1 (D2) formed by the blowing direction X of the green sand entering the mold 20 from the blowing head 48 through the sand introduction passage 86 and the blowing direction Y1 (Y2) of the compressed air directed toward the green sand through the at least one compressed air introduction passage P1 (P2) is set to an acute angle.

In the sand mold manufacturing apparatus 10 according to one embodiment of the present invention, the wet sand blown from the blowing head 48 toward the mold 20 is blown into the mold 20 while being stirred and finely dispersed in the sand introducing passage 86 and in the vicinity of the opening 26a of the mold 20 by the compressed air blown from the compressed air introducing passage P1 (P2) of the blow-plate unit 56. Since the angle D1 (D2) formed by the blowing direction X of the green sand entering the mold 20 from the blowing head 48 through the sand introduction passage 86 and the blowing direction Y1 (Y2) of the compressed air directed toward the green sand through the compressed air introduction passage P1 (P2) is set to an acute angle, the compressed air from the compressed air introduction passage P1 (P2) plays a role of pushing the green sand into the mold 20 from the rear, thereby improving the fillability of the green sand with respect to the cavity 24a of the mold 20. As a result, the mold 20 can be properly filled with the wet sand, whereby even a sand mold having a complicated shape can be properly manufactured.

In one embodiment, sand introducing channel 86 includes an inlet 88 located on a side closer to blowing head 48 and an outlet 90 located on a side closer to mold 20; and the aperture area Ao of the outlet 90 is larger than the aperture area Ai of the inlet 88.

When the aperture area Ao of the outlet 90 of the sand introducing passage 86 is larger than the aperture area Ai of the inlet 88, the flow rate of the wet sand passing through the sand introducing passage 86 is slower at the outlet 90 than at the inlet 88. Thus, the wet sand collides with itself in the sand introducing passage 86 to be further stirred, and is further dispersed at the outlet 90 wider than the inlet 88. As a result, the wet sand has less linear movement ability, so that the wet sand mass is less likely to adhere (stick) to the mold 20, and thus a molded article (sand mold) having good mold release properties is obtained.

Another sand mold manufacturing apparatus 10 according to an embodiment of the present invention is a sand mold manufacturing apparatus that manufactures a sand mold by blowing wet sand into a mold 20, including: a blowing head 48 for retaining the wet sand; and a blow-plate unit 56 disposed between the blow head 48 and the mold 20. The blow-plate unit 56 includes: a sand introducing passage 86 through which the wet sand blown from the blowing head 48 to the mold 20 by the compressed air supplied to the blowing head 48 passes through the sand introducing passage 86; and at least one compressed air introduction passage P1 (P2) for blowing compressed air toward the wet sand blown into the mold 20 through the sand introduction passage 86. The sand introducing passage 86 includes an inlet 88 located on a side closer to the blowing head 48 and an outlet 90 located on a side closer to the mold 20; and the aperture area Ao of the outlet 90 is larger than the aperture area Ai of the inlet 88.

In the other sand mold manufacturing apparatus 10 according to the one embodiment of the present invention, the wet sand blown from the blowing head 48 toward the mold 20 is blown into the mold 20 while being stirred and finely dispersed in the sand introducing passage 86 and in the vicinity of the opening 26a of the mold 20 by the compressed air blown from the compressed air introducing passage P1 (P2) of the blow-plate unit 56. Since the aperture area Ao of the outlet 90 of the sand introducing passage 86 is larger than the aperture area Ai of the inlet 88, the flow rate of the wet sand passing through the sand introducing passage 86 is slower at the outlet 90 than at the inlet 88. Thus, the wet sand collides with itself in the sand introducing passage 86 to be further stirred, and is further dispersed at the outlet 90 wider than the inlet 88. As a result, the wet sand has less linear movement ability, so that the wet sand mass is less likely to adhere (stick) to the mold 20, and thus a molded article (sand mold) having good mold release properties is obtained.

In one embodiment, the aperture area Ao of the outlet 90 is larger than the sum of the aperture area Ai of the inlet 88 and the aperture area Aa (Ab) of the blowout port 95a (95 b) of the at least one compressed air introduction passage P1 (P2).

When the aperture area Ao of the outlet 90 of the sand introducing passage 86 is larger than the sum of the aperture area Ai of the inlet 88 and the aperture area Aa (Ab) of the blowout port 95a (95 b) of the compressed air introducing passage P1 (P2), the difference between the aperture area Ai of the inlet 88 and the aperture area Ao of the outlet 90 can be further increased, thereby allowing the wet sand passing through the sand introducing passage 86 to be further stirred and dispersed. Therefore, it is possible to further suppress the adhesion of the wet sand mass to the mold 20.

In one embodiment, the wet sand comprises an inorganic binder.

Generally, inorganic binders have a strong binding power. Therefore, in the case where the wet sand contains an inorganic binder, once the wet sand sticks to the mold 20, the sand mold becomes difficult to be ejected from the mold 20, so that forced attempts to eject it may cause damage to the sand mold. Because the aperture area Ao of the outlet 90 is larger than the aperture area Ai of the inlet 88, even in the case where the green sand contains an inorganic binder, the green sand can be sufficiently stirred and dispersed, thereby allowing the green sand mass to be appropriately suppressed from adhering to the mold 20.

In one embodiment, the at least one compressed air introduction passage includes a plurality of compressed air introduction passages P1, P2, and the plurality of compressed air introduction passages P1, P2 are formed such that compressed air blown from the plurality of compressed air introduction passages P1, P2 collides with each other.

Since compressed air is blown from the plurality of compressed air introduction passages P1, P2 to collide with each other, stirring and dispersion of the wet sand are further promoted. This enables the mold 20 to be filled with wet sand more appropriately.

In one embodiment, blow-plate unit 56 includes a blow plate 58 disposed between blow head 48 and mold 20, and a hollow cylindrical liner 60; the blow plate 58 has a communication hole through which the blow head 48 and the die 20 communicate with each other; the bushing 60 is disposed in the communication hole of the blow plate 58 and includes a sand introduction passage 86.

In one embodiment, at least one compressed air introduction passage P1 (P2) is formed from the blow plate 58 to the liner 60.

When the compressed air introduction passage P1 (P2) is formed from the blow plate 58 to the liner 60 (i.e., when the compressed air introduction passage includes a "first portion" formed in the blow plate 58 and a "second portion" formed in the liner 60), the blowing direction Y1 (Y2) of the compressed air with respect to the sand introduction passage 86 or other conditions can be easily changed by replacing the liner 60.

In one embodiment, the blow-plate unit 56 further includes a vent plug 59 disposed at a location of at least one compressed air introduction passage formed in the liner 60 g.

When the vent plug 59 is provided at a portion (second portion) of the compressed air introduction passage formed in the liner 60g, the pneumatic device can be protected from the wet sand intruded into the compressed air introduction passage.

In one embodiment, the at least one compressed air introduction passage comprises a plurality of compressed air introduction passages; the bushing 60g has a groove portion 142 formed in an annular shape on the outer periphery, and the groove portion 142 constitutes a part of the plurality of compressed air introduction passages.

In the case where there are a plurality of compressed air introduction passages, when the bush 60g includes the groove portion 142 formed in a ring shape at the outer periphery, the groove portion 142 constitutes a part of the plurality of compressed air introduction passages, and the compressed air can be supplied from one first portion to a plurality of second portions via the groove portion 142. Accordingly, for the plurality of second portions formed in the liner 60g, it is not necessary to separately form the first portions in the blow plate 58. Thus, in the case where a plurality of sand introducing passages 86g are provided in the blow-plate unit 56, this allows a plurality of bushings 60g to be closely arranged together.

Industrial applicability

REFERENCE SIGNS LIST

10,10a,10b,10c,10d,10e,10f,10g sand mold manufacturing apparatus

20,20c,20d,20e mold

26a,26b,116,136 openings

48. Blowing head

56,56a,56b,56c,56d,56f,56g blow plate unit

58,58a,58f,58g blow plate

60,60f,60g,96 bushing

62,98 communicating hole

86,86b,86c,86g sand introduction passage

88,108,112 inlet

90. An outlet

95a,95b air outlets

Aperture area of Ai inlet

Aperture area of Ao outlet

Aperture area of Aa, ab outlet

Angles B, D1, D2

P1, P2, P3, P4, P5, P6, P7, P8 compressed air introduction passage

Blowing direction of X wet sand

Y1, Y2 direction of blowing of compressed air

Claims

1. A sand mold manufacturing apparatus for manufacturing a sand mold by blowing wet sand into a mold, the sand mold manufacturing apparatus comprising:

a blowing head for retaining the wet sand; and

a blowing plate unit disposed between the blowing head and the mold, wherein,

the blow-plate unit includes:

At least one compressed air introduction passage for blowing compressed air toward the green sand blown into the mold through the sand introduction passage; and is also provided with

An angle formed by a blowing direction of the green sand from the blowing head into the mold through the sand introduction passage and a blowing direction of the compressed air toward the green sand through the at least one compressed air introduction passage is set to be an acute angle.

2. The sand mold manufacturing apparatus according to claim 1, wherein,

The aperture area of the outlet is larger than the aperture area of the inlet.

3. The sand mold manufacturing apparatus according to claim 2, wherein the aperture area of the outlet is larger than a sum of the aperture area of the inlet and an aperture area of a blow-out port of the at least one compressed air introduction passage.

4. A sand mould apparatus as claimed in claim 2 or claim 3, wherein the wet sand comprises an inorganic binder.

5. The sand mold manufacturing apparatus according to claim 1 or 2, wherein,

6. The sand mold manufacturing apparatus according to claim 1 or 2, wherein,

the blow-plate unit includes:

a blowing plate disposed between the blowing head and the mold, and

a bushing having a hollow columnar shape;

the blow plate has a communication hole through which the blow head and the die communicate with each other; and is also provided with

The bushing is provided in the communication hole of the blow plate and includes the sand introduction passage.

7. A sand mold manufacturing apparatus that manufactures a sand mold by blowing wet sand into a mold, the sand mold manufacturing apparatus comprising:

a blowing head for retaining the wet sand; and

a blowing plate unit disposed between the blowing head and the mold, wherein,

the blow-plate unit includes:

at least one compressed air introduction passage for blowing compressed air toward the green sand blown into the mold through the sand introduction passage;

The aperture area of the outlet is larger than the aperture area of the inlet.

8. The sand mold manufacturing apparatus of claim 7, wherein the aperture area of the outlet is greater than a sum of the aperture area of the inlet and an aperture area of a blow-out port of the at least one compressed air introduction passage.

9. The sand mold manufacturing apparatus of claim 7 or 8, wherein the wet sand comprises an inorganic binder.

10. The sand mold manufacturing apparatus according to claim 7 or 8, wherein,

11. The sand mold manufacturing apparatus according to claim 7 or 8, wherein,

the blow-plate unit includes:

a blowing plate disposed between the blowing head and the mold, and

a bushing having a hollow columnar shape;

12. The sand mold apparatus of claim 11, wherein the at least one compressed air introduction passage is formed from the blow plate to the liner.

13. The sand mold manufacturing apparatus of claim 12, wherein the blow plate unit further comprises a vent plug disposed at a location of the at least one compressed air introduction passage formed in the liner.

14. The sand mold manufacturing apparatus according to claim 12 or 13, wherein,