JPH0523792A - Manufacture of hollow structural body - Google Patents

Abstract

PURPOSE:To mass-produce hollow structural bodies difficult to form by casting the hollow structural body from casting space constituted with core body and metallic mold. CONSTITUTION:The core body 27 is formed with a wax pattern 30 and a refractory 31 coated on this outer surface and also the casting space is constituted with the core bodies 27 and the metallic mold 28. Molten metal is poured into the casting space, and after cooling, the refractory and the wax pattern are melted from a casting blank 29 to cast the hollow structural body 26. By this method, the core body is melted and discharged, and even in the case of manufacturing the casting having complex outer shape and thin part, the core body can be easily removed and the mass-production to the castings difficult to form to the hollow structure, can be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow structure such as a roller used in a rotary positive displacement compressor applied to an air conditioner.

[0002]

2. Description of the Related Art Conventionally, it has been known to use castings for parts of rotary positive displacement compressors.

There is a rolling piston type compressor as one type of rotary displacement type compressor. For example, a high pressure dome type rolling piston type compressor is often used in an air conditioner. This high-pressure dome type rolling piston compressor has a compression unit housed in a completely sealed casing. This compression unit forms a pressure chamber by a disk-shaped cylinder block fixed to a casing, a pair of plates that close the upper and lower openings of the block, and a ring-shaped roller that is driven to rotate by a crankshaft in the pressure chamber. Then, the roller is rotationally driven to suck the refrigerant gas into the pressure chamber and pressurize and discharge the refrigerant gas. Casting is used for the cylinder block, the rotor, and the like.

[0004]

In the above rolling piston type compressor, the inside of the casing is constituted by the cylinder block and the upper gas chamber in which the motor is accommodated and the lower oil chamber in which the lubricating oil is stored. It is divided into. The sliding contact points such as the cylinder block, the roller, the crankshaft and the blade are forcibly lubricated by the oil in the oil chamber.

Further, since the cylinder block and the rollers are filled with oil, and the rolling piston type compressor is of a high pressure dome type, the oil has a high temperature due to the high temperature and high pressure atmosphere in the casing. Here, the temperature in the pressurizing chamber is greatly affected by the temperatures of the cylinder block and the rollers. Therefore, when the temperature of the cylinder block and the rollers become high, the specific volume of the refrigerant gas sucked into the pressurizing chamber increases due to the heat, and the volumetric efficiency of the compressor decreases. Therefore, it is required to form the space by hollowing the cylinder block and the roller, but it is difficult to mass-produce a cylinder block having a complicated outer shape and a thin wall portion having a hollow portion in a large amount. there were.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a manufacturing method suitable for mass production of a hollow structural body in which a hollow structure is difficult to form.

[0007]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the means taken by the invention according to claim 1 is a method for producing a hollow structure (26) having a space (23) in a meat wall. Assumption.

Specifically, a core body forming step (A) in which a refractory material (31) is coated on the outer surface of the wax model (30) to form a core body (27) having the same shape as the space (23).
1) is provided. Then, the hollow structure (2
The core body (27) is placed in an outer mold (28) that defines the outer surface shape of 6), and molten metal is poured into a casting space between the outer mold (28) and the core body (27). A casting process (A2) is provided. Furthermore, after cooling the casting blank (29) cast in the casting step (A2) and releasing the solidified casting blank (29) from the outer die (28),
Refractory (31) by reacting the refractory layer with a strong alkaline solution
A refractory leaching step (A3) for leaching the refractory to the outside of the casting blank (29) is provided. In addition, after the refractory elution step (A3) is finished, a dewaxing step (A4) is provided to elute the wax model (30) remaining in the space (23) in the casting blank (29). Finally, after the completion of the dewaxing step (A4), the casting blank (37) is subjected to a predetermined finishing treatment to finish it in a predetermined state (A
5) is provided.

Further, in addition to the method for manufacturing the hollow structure (26), the means taken by the invention according to claim 2 is an upper model (35a) and a lower model (35a) formed of foamed plastic beads that are melted by a molten metal. By the model (35b),
The hollow structure (26) has a hollow portion (38) inside.
A vanishing model forming step (B1) for forming a vanishing model (35) having the same shape as the above is provided. The refractory material (3) is attached to the outer surface of the vanishing model (35) and the hollow portion (38).
A mold forming step (B2) of coating 1) to form a mold (36) is provided. Furthermore, after the completion of the mold forming step (B2), molten metal is poured into the casting space occupied by the disappearing model (35), and the disappearing model (35) is melted by the molten metal and immersed in the mold (36). A casting process (B) in which the molten metal is filled in the casting space while allowing it to flow.
3) is provided. In addition, after the casting blank (37) cast in the casting step (B3) is cooled and solidified, a strong alkaline solution is caused to react with the refractory layers inside and outside the mold (36) to thereby form the refractory (31). The refractory removal process (B4) of removing (4) is provided. Lastly, after the refractory removal step (B4) is completed, a finishing step (B5) is provided in which the casting blank (37) is subjected to a predetermined finishing treatment to a predetermined state.

According to a third aspect of the present invention, in the method for manufacturing a hollow structural body according to the first or second aspect, the hollow structural body (26) is replaced by a cylinder (4) and a roller of a rotary positive displacement compressor. (5) One or both.

[0011]

With the above construction, according to the invention of claim 1, a core body (27) is formed by the wax model (30) and the refractory material (31) coated on the outer surface thereof, and the core body is formed. The casting space is formed by (27) and the outer mold (28). Molten metal hot water is poured into this casting space, and after cooling,
The refractory material (31) and the wax model (30) are eluted from the casting blank (29) to cast a hollow structure (26).
Therefore, since the core body (27) is melted and discharged by using the wax model (30) coated with the refractory material (31), the core body (27) can be cast even if it has a complicated outer shape or a thin portion. The body (27) will be easily removed, and it becomes possible to mass-produce castings in which it is difficult to form a hollow structure.

According to the second aspect of the present invention, the refractory material (31) is coated on the outer surface and the hollow portion (38) of the disappearing model (35) formed of foamed plastic beads to form the mold (36). The hollow structure (26) is formed by melting the extinguishing model (35) by the heat of the molten metal, allowing it to penetrate into the refractory layer of the mold (36), and then eluting the refractory (31). ) Is formed. Therefore, the core body (27) is easily removed. Further, the pouring space is filled with the disappearing model (35), and the hot water poured in the pouring process fills the filling portion of the disappearing model (35) to form the pouring space accurately. become. That is, the situation in which the core moves due to the pouring and the wall thickness between the space (23) and the outer dimension is changed is eliminated. As a result, it becomes possible to mass-produce castings in which it is difficult to form a hollow structure.

According to the third aspect of the present invention, a space (23) having a smaller thermal conductivity than that of the casting is formed in one or both of the cylinder (4) and the roller (5) of the rolling piston compressor. As a result, the heat transfer path for heat transferred from the cylinder (4) and the roller (5) to the pressurizing chamber is reduced.

[0014]

Therefore, according to the invention of claim 1, the core body (27) can be easily removed from the casting blank (29), and according to the invention of claim 2. By filling the casting space with the vanishing model (35), it is possible to continuously manufacture a large amount of hollow structures in which it is difficult to form a hollow structure due to a complicated outer shape or a thin portion.

According to the third aspect of the invention, the space (2) is provided in one or both of the cylinder (4) and the roller (5).
Since a rolling piston type compressor having 3) can be manufactured, heating of the refrigerant gas sucked into the pressurizing chamber is mitigated to prevent an increase in specific volume, and the volumetric efficiency of the rotary positive displacement type compressor is improved. can do.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the following examples, an example in which the method for manufacturing a hollow structure according to the present invention is applied to a rolling piston type compressor which is one of rotary displacement type compressors will be described.

1 to 3 show a first embodiment. First, the structure of the rolling piston compressor is shown in FIGS. 1 and 2. The rolling piston compressor is composed of a closed barrel-shaped casing (1), and a motor (2) and a compression unit (3) arranged above and below the casing (1). The power of the motor (2) is compressed by the compression unit (1). It is transmitted to 3) and compresses fluid such as refrigerant gas.

The compression unit (3) comprises a cylinder (4)
A roller (5) housed in the cylinder (4) and rotating along the inner peripheral wall of the cylinder (4); and a cylinder (4)
A front muffler (6) provided on the outer surface of the roller and a partition blade (7) circumscribing the roller (5). The cylinder (4) divides the inside of the casing (1) into a lower oil chamber (8) and an upper gas chamber (9).

The cylinder (4) includes a cylinder body (10) made of a disk-shaped metal block and a cylinder body (1).
0) which is composed of a front plate (11) and a rear plate (12) for closing the upper and lower ends thereof, and these members (1
A pressure chamber (13) is formed inside by (0) to (12). (14) is a gas inlet. Pressurized chamber (13)
The reed valve 1 on the front plate (11) facing the
A discharge port (16) that is opened and closed at (5) is provided.

The motor (2) comprises a stator (17) fixed to the inner surface of the casing (1) and a crankshaft (18).
And a rotor (19) directly connected to the roller (5) and rotationally drives the roller (5) via the crankshaft (18). The crankshaft (18) is rotatably supported by the upper and lower plates (11) and (12), and has an eccentric shaft portion (20) fitted in the roller (5) in the middle thereof. The roller (5) is a pressure chamber (1
3) Rolls and moves in a certain direction along the inner peripheral surface of 3), compresses the suction gas while continuously changing the volumes of the low pressure chamber and the high pressure chamber divided by the roller (5) and the blade (7). And discharge from the discharge port (16). Reference numeral (21) is an oil chamber (1
It is the oil stored in 8).

In this embodiment, the space (23) is formed in the wall of the cylinder body (10). In FIG. 2, the space (23) is formed in a C-shaped cross section, avoiding the gas passage (24) communicating the gas inlet (14) with the pressurizing chamber (13).

Here, with respect to the refrigerant gas sucked into the pressurizing chamber (13), the heating amount by the heat transfer from the outside of the cylinder excluding the temperature rise due to compression is the total amount of heat transfer between the cylinder body and the roller. Each occupies approximately 40%, and the remaining approximately 20% is occupied by the upper and lower plates and blades. Therefore, the cylinder body (10) that is greatly affected by heat transfer
By providing the space (23) in the above, the amount of heat transfer can be effectively reduced. Of course, even if the space (23) is provided in the roller (5), the heat transfer amount can be reduced to the same degree, and the cylinder body (1
If space (23) is provided in both 0) and roller (5),
Furthermore, the amount of heat transfer can be reduced. When the space (23) is provided in the roller (5), the space (23) is formed in an endless ring shape because there are no obstacles such as gas passages in the meat wall.

Next, as a feature of the present invention, the space (23)
Cylinder body (10) or roller (5) having
That is, a method of manufacturing the hollow structure (26) will be described.
This manufacturing method is an application of the lost wack method, which can obtain a precision cast product.

In this casting method, as shown in FIGS. 3A to 3F, a core forming step (A) for forming a core (27) is performed.
1), a casting step (A2) in which the core body (27) is placed in a mold (28) as an outer mold and molten metal is poured, and the core body (27) is cast after the metal is solidified. (29) It comprises a refractory elution step (A3) and a dewaxing step (A4) which are removed from the inside, and a finishing step (A5) (not shown) for finishing the casting blank (29). To produce a hollow structure (26).

The core forming process (A) shown in FIGS.
In 1), a cylindrical wax model (30) is manufactured by a model die (not shown), a refractory material (31) is coated on the outer surface thereof, and the refractory material (31) is further provided at three or more places on the lower surface thereof. The shape of the core body (27) excluding the support legs (32) is finished with the same shape as the space (23) of the completed hollow structure (26).

The mold (28) used in the casting step (A2) of FIG. 3 (c) comprises an upper mold (28a) and a lower mold (28b), and one mold is placed on the upper surface of the upper mold (28a). Spout (28
c) and has a core (28) at the center of the inner surface of the lower mold (28b).
d) is integrally projected. The inner shape of the mold (28) is formed larger than the outer shape of the hollow structure (26) by a machining allowance. Inside the mold (28), the support legs (3
Place the core (27) with the upper mold (28) facing down.
After fixing the a) and the lower mold (28b), the spout (28
The molten metal is poured from c) to fill the casting space.

In the refractory elution step (A3) of FIG. 3 (d), the upper mold (28a) and the lower mold (28b) are separated and the solidified casting blank (29) is released from the mold (28). To do. Next, a strong alkaline solution is poured into the refractory material (31) through the hole (33) formed in the part that was the supporting leg (32).
Is eluted out of the casting blank (29). As a result, a casting blank (29) in which only the wax model (30) remains in the space (23) is obtained.

In the dewaxing step (A4) of FIG. 3 (e), the wax model (30) is heated and melted, and the wax model (30) is made into the holes (3).
3) is discharged to the outside, and the entire casting blank (29) is heated to burn off the wax adhered to the peripheral wall of the space (23).

In the finishing step of FIG. 3 (f), the hollow structure (26) is finished in a predetermined state by subjecting the casting blank (29) to cutting, heat treatment, grinding and the like to obtain a finished product.
If necessary, plug the hole (33).

According to the present embodiment, the core body (27) is formed by the wax model (30) and the refractory material (31) coated on the outer surface thereof, and the core body (27) and the mold ( 28)
And form the casting space. The molten metal is poured into this casting space, and after cooling, the refractory material (31) and the wax model (30) are eluted from the casting blank (29) to cast the hollow structure (26). Therefore, since the core body (27) is melted and discharged by using the wax model (30) coated with the refractory material (31), the core body (27) can be cast even if it has a complicated outer shape or a thin portion. Body (27)
Will be easily removed, and it will be possible to mass-produce castings in which it is difficult to form a hollow structure.

A space (23) is provided in the wall of the cylinder body (10), and the cross-sectional area of the heat transfer path from the outside of the cylinder to the pressurizing chamber (13) is reduced.

As a result, the core body (27) can be easily removed from the casting blank (29),
It is possible to continuously manufacture a large amount of a hollow structure body in which it is difficult to form a hollow structure such as having a complicated outer shape or a thin portion.

Further, by forming the space (23) in one or both of the cylinder (4) and the roller (5), the refrigerant gas having a temperature higher than that of the hole (33) is kept in the space (23).
Flows in. The thermal conductivity of the refrigerant gas is 0.143 Kcal /
Roller (5) that is a casting, while it is about mh ℃
Since it is about 41 Kcal / mh ℃, etc., cylinder (4)
And the heat transfer path of the heat transmitted from the roller (5) to the pressure chamber is reduced. Therefore, the heating of the refrigerant gas sucked into the pressurizing chamber can be relaxed to prevent an increase in the specific volume, and the volumetric efficiency of the rolling piston compressor can be improved.

Next, FIGS. 4 (a) to 4 (g) show a second embodiment of the method for producing the hollow structure (26). In this example,
It is an application of the lost form method.

The casting method comprises a vanishing model forming step (B1) for forming the vanishing model (35) and a mold forming step for coating the vanishing model (35) with a refractory material (31) to form a mold (36). (B2), a casting step of pouring molten metal into the mold (36), (B3), and a refractory removing step (B) of removing the refractory (31) to obtain a casting blank (37).
4) and a finishing step (B5) for finishing the casting blank (37) though not shown.

In the disappearing model forming step (B1) of FIGS. 4 (a) and 4 (b), an upper model (35a) made of expanded plastic beads, for example, expanded polystyrene beads and a lower model are formed by using a model mold not shown. The models (35b) are individually manufactured, and these are joined to form the vanishing model (35). The vanishing model (35) is formed larger than the completed hollow structure (26) by a machining allowance, and has a hollow portion (38) corresponding to the space (23) therein. To obtain this hollow portion (38), the vanishing model (35) is divided into an upper model (35a) and a lower model (35b). A spout (35c) for injecting a refractory material (31) into the lower model (35b).
Is provided.

The mold forming step (B) shown in FIGS.
In 2), the model (35) is inverted and the spout (35
Injecting the refractory material (31) into the hollow portion (38) from c),
Further, the refractory material (31) is coated on the outer surface of the vanishing model (35) to form a mold (36). At this time, a pouring port (39) is opened at one place on the upper surface of the refractory layer.

In the casting step (B3) of FIG. 4 (e), molten metal is poured from the pouring port (39) with the disappearing model (35) still existing, and the disappearing model is melted by the heat,
The casting space is filled with the molten metal while being immersed in the mold (36).

In the refractory elution step (B4) of FIG. 4 (f), the refractory material (31) on the outer surface of the casting blank (37) is crushed and removed, and a strong alkali solution is poured from the pouring port (35). , The refractory (3) filled in the hollow part (38)
Elute 1) out of the casting blank (37).

In the finishing step (B5) of FIG. 4 (g), the casting blank (37) is subjected to cutting, heat treatment, grinding, etc. to finish it into a predetermined shape to obtain a hollow structure (26).

According to this embodiment, the refractory material (31) is coated on the outer surface and the hollow portion (38) of the disappearance model (35) formed of expanded polystyrene beads, and the mold (3) is coated.
6) is formed and disappears by the heat of molten metal (35)
Is melted and allowed to soak into the refractory layer of the mold (36), and then the refractory (31) packed inside is eluted to form the hollow structure (26). Therefore, the core body (27) is easily removed. Furthermore, the pouring space, which is the pouring space, is completely filled with the disappearing model (35), and the hot water poured in the pouring process disappears (35).
The space (23) is accurately formed by filling the filled portion of the space. Therefore, the situation that the core moves due to the pouring and the wall thickness between the space (23) and the outer dimension is deviated is solved, and it becomes possible to mass-produce a casting in which a hollow structure is difficult to form.

As a result, the refractory (3
By filling the vanishing model (35) filled with 1), it is possible to continuously manufacture a large amount of a hollow structure in which it is difficult to form a hollow structure due to a complicated outer shape or a thin portion.

In the second embodiment, the disappearance model (3
The upper mold (35a) and the lower mold (35b) constituting 5) can also take forms other than those shown in FIG. For example, all of the hollow part (38) is formed in either the upper mold (35a) or the lower mold (35b), and the opening edge thereof is a flat plate-shaped lower mold (35).
b) or the upper mold (35a).

In this embodiment, a rolling piston type compressor is taken as an example of the rotary positive displacement type compressor, but the present invention can be applied to vane type, screw type and other rotary positive displacement type compressors. The present invention also provides a cylinder body (1
0) and parts other than the roller (5), for example, the front plate (11) and the rear plate (12). Furthermore, the invention according to claim 1 or 2 may be applied to various hollow structures other than the compressor.

Further, in the first embodiment, the space (23)
In the case of having a C-shaped cross section, the core body (27) is formed in a C-shape in plan view. The support leg (32) is not always necessary, and a corresponding protrusion may be provided on the mold (28).

In the second embodiment, the vanishing model (3
The upper mold (35a) and the lower mold (35b) constituting 5) can also take forms other than those shown in FIG. For example, all of the hollow part (38) is formed in either the upper mold (35a) or the lower mold (35b), and the opening edge thereof is a flat plate-shaped lower mold (35).
b) or the upper mold (35a).

The expanded plastic beads may be other than expanded polystyrene beads.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a rolling piston compressor.

FIG. 2 is a sectional view taken along line AA in FIG.

3 (a), (b), (c), (d), (e) and (f) show a manufacturing process of the hollow structure body in the first embodiment, and (a) and (b) show It is a process explanatory view showing a core forming process, (c) a casting process, (d) a refractory elution process, (e) a dewaxing process, and (f) a finishing process.

4 (a), (b), (c), (d), (e),
(F) and (g) show the manufacturing process of the hollow structure in the second embodiment, (a) and (b) show the disappearance model forming step, (c) and (d) show the template forming step, 3E is a process explanatory diagram showing a pouring process, FIG. 6F is a refractory removing process, and FIG. 4G is a finishing process.

[Explanation of symbols]

4 cylinders 5 roller 23 space 26 Hollow structure 27 Core 28 Mold (outer mold) 29 casting blank 30 wax model 31 refractory 35 disappearance model 36 Mold 38 hollow A1 core body formation process A2 casting process A3 refractory elution process A4 dewaxing process B1 Disappearance model formation process B2 mold forming process B3 casting process B4 refractory removal process

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area F04C 18/356 H 8608-3H

Claims (3)

[Claims] 1. A method of manufacturing a hollow structure (26) having a space (23) in a meat wall, wherein a refractory material (31) is coated on the outer surface of a wax model (30) to produce the space (23). A core body forming step (A1) of forming a core body (27) having the same shape as that of the outer structure (2) for defining the outer surface shape of the hollow structure (26).
8) A casting step (A2) in which the core body (27) is placed inside and a molten metal is poured into a casting space between the outer die (28) and the core body (27); After cooling the casting blank (29) cast in the step (A2) and releasing the solidified casting blank (29) from the outer die (28), the refractory layer is reacted with a strong alkaline solution to obtain fire resistance. Blank (29) for casting object (31)
The refractory leaching step (A3) for leaching out of the refractory, and the wax model (30) remaining in the space (23) in the casting blank (29) after the refractory leaching step (A3).
A dewaxing step (A4) for eluting the molten steel, and the casting blank (3) after the dewaxing step (A4) is completed.
7. A method for producing a hollow structure, comprising the step 7) of performing a predetermined finishing treatment to finish in a predetermined state. 2. A method for manufacturing a hollow structure (26) having a space (23) in a meat wall, comprising an upper model (35a) and a lower model (35b) formed of foamed plastic beads that are melted by a melting material. ) Has a hollow part (38) inside, and the hollow structure (2
6) A vanishing model forming step (B1) for forming a vanishing model (35) having the same shape as that of 6), and a refractory (31) is coated on the outer surface and the hollow portion (38) of the vanishing model (35) to mold ( 36) to form a template (B2), and after the completion of the template forming step (B2), the disappearance model (3)
Molten metal is poured into the casting space occupied by 5), and the vanishing model (35) is melted by the molten metal to mold (3).
6) A casting step (B3) in which the casting space is filled with molten metal while being immersed in the casting step, and the casting blank (37) cast in the casting step (B3) is cooled and solidified, and then the mold The refractory layer inside and outside (36) is reacted with a strong alkaline solution to form the refractory (3
A refractory removing step (B4) of removing 1), and a finishing step (B5) of finishing the refractory removing step (4) to a predetermined state by subjecting the casting blank (37) to a predetermined finishing treatment. A method for manufacturing a hollow structure, comprising: 3. Hollow structure according to claim 1 or 2, characterized in that the hollow structure (26) is one or both of a cylinder (4) and a roller (5) of a rotary positive displacement compressor. Production method.