JPH0532582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor block and a molding device thereof, and more particularly to a carburetor block that constitutes the main body of a carburetor used in an internal combustion engine, and a method for molding the carburetor block. The present invention relates to a carburetor block molding apparatus which prevents the occurrence of molding defects as much as possible when molding, and which uses a gate part of a mold used for introducing molten material to attach parts after molding is completed.

In internal combustion engines, a carburetor that applies the principle of atomization is generally employed as a fuel supply device. In this case, the carburetor uses the high-velocity airflow generated during the engine's intake stroke to suck out fuel, atomizes the fuel, and mixes it with air to create an air-fuel mixture. After the mixture is sucked into the cylinder, it is compressed by the piston and ignited by the spark plug to burn. The piston is pressed by the explosive force of the fuel at this time, and the pressing force is converted into rotational force by a crank connected to the piston.

Incidentally, conventionally, various flow paths including an intake passage through which air-fuel mixture flows are formed in the carburetor body as described above, and parts such as valves are disposed.
Therefore, since the carburetor body necessarily has a complicated shape, it is common that the carburetor body is integrally molded from metal, for example, zinc or aluminum alloy. However, in automobile engines, etc., it is desired to reduce the weight of the engine, and when using a conventional metal carburetor body,
Even if the type of metal is changed, there is a limit to how much weight can be reduced. Therefore, in recent years, synthetic resins, namely,
Attempts have been made to mold the carburetor body using engineering plastics. In this case, it is possible to reduce the weight of the carburetor body by using a synthetic resin material that has excellent heat resistance, rigidity, and fuel corrosion resistance, and is also lighter than metal. Become.

Next, such a carburetor body will be explained.

In FIG. 1, reference numeral 2 indicates a carburetor body, and this carburetor body 2 is connected to a throttle body block 4 and a mixture body block 6.
and an air horn block 8.
In this case, the throttle body block 4 is made of metal such as zinc or aluminum alloy, and the mixture body block 6 and air horn block 8 are made of synthetic resin. Further, the blocks 4, 6, and 8 are integrated in a stacked state as shown in the figure.

The carburetor body 2 has a main intake passage 10 and a secondary intake passage 12 that pass through the carburetor body 2.
are formed in parallel. In this case, outer bench lilies 14 and 16 formed in the mixture body block 6 are formed at intermediate portions of the main intake passage 10 and the secondary intake passage 12, respectively. An inner bench lily 1 is located upstream of the outer bench lilies 14 and 16.
8 and 20 are formed. Furthermore, a choke valve 22 is provided in the main intake passage 10 of the air horn block 8.
is pivotally supported, while the throttle body block 4
Throttle valves 24 and 26 are pivotally supported in the main intake passage 10 and the secondary intake passage 12 at. In addition, during the intake process of the engine in which the carburetor main body 2 is installed, fuel is mixed with air through the flow path defined by the outer bench lily 14, 16 and the inner vent lily 18, 20, and the fuel is mixed with the air and transferred to the cylinder (not shown). It will be introduced inside.

By the way, in addition to the outer bench lilies 14 and 16, various holes and recesses such as float chambers must be formed in the mixture body block 6. Therefore, when injection molding the mixture body block 6, a cavity for the molded product must be defined using a plurality of molds each having a predetermined shape of unevenness and provided with a core pin.

In this case, when supplying the molten resin into the cavity, the molten resin is injected at a predetermined pressure through a gate communicating with the cavity. When performing molding in this way, by providing the gate in advance at a position relatively close to the center of the cavity, it is possible to equalize the filling pressure of the molten resin throughout the cavity and to ensure suitable injection without insufficient filling. It is desirable to carry out the process. However, when the molten resin is injected into the cavity, the molten resin flows inside the cavity in a pulsating manner along the peripheral wall of the cavity, and as a result, approximately concentric waveforms centered on the gate are formed on the surface of the molded product. There is a tendency to produce roughness that exhibits a pattern, that is, flow marks. Needless to say, this results in poor molding.

On the other hand, in the mixture body block 6, if the joint surfaces with the throttle body block 4 and the air horn block 8 are not formed smoothly, when assembling the carburetor body 2,
It becomes difficult to connect various channels in an airtight manner.
Therefore, according to the prior art, a gate has to be provided at a position corresponding to the end of the mixture body block 6 on the side wall side. However, when the gate is provided at such a position, it is difficult to inject the molten resin into the entire cavity, which may lead to insufficient filling of the molten resin.

Furthermore, it is necessary to form a large number of holes in the air horn block 8 side of the mixture body block 6. Correspondingly, the air horn block 8 is installed in the cavity.
A large number of core pins for forming the holes are disposed at portions corresponding to the sides. Therefore, if a gate is provided on the side where there are many core pins,
It becomes difficult for the molten resin to flow smoothly, making it impossible to perform a suitable molten resin injection process. That is, since the mixture body block 6 itself has a complicated shape, it is difficult to arbitrarily select the placement position of the gate, and there are various constraining factors. There was a disadvantage that it could not be easily molded.

The present invention has been made in order to overcome the above-mentioned disadvantages, and includes providing a gate portion corresponding to an approximately intermediate portion between the downstream side of the intake path defined in the carburetor block and the bottom of the float chamber. In the carburetor block, a hole-shaped gate reservoir that constitutes a part of the molded product cavity is formed on the tip end side of the gate, and a core pin that enters the gate reservoir is provided. A molding hole is formed inside the protrusion formed by the gate reservoir, and the molding hole is configured to be used as a hole for inserting a predetermined part, and as a result, the fluidity of the molten resin is improved. It is an object of the present invention to provide a carburetor block and its molding device, which allow a suitable injection process to be performed on the cavity, and which do not affect the function of the carburetor block even if flow marks are formed on the protrusion. do.

To achieve the above object, the present invention provides a float chamber into which fuel is introduced by supplying molten resin through a gate into a cavity defined by a mold, and a float chamber in which fuel is mixed with air. In a carburetor block in which one or more air intake passages are molded, the downstream side of the intake passage is open, and a protrusion is formed near the center of the surface including the bottom of the float chamber, facing the gate for introducing molten resin. The method is characterized in that a hole for inserting a component is formed inside the protrusion.

Furthermore, the present invention provides a molding device equipped with a plurality of molds for molding a carburetor block having a float chamber into which fuel is introduced and one or more intake passages through which the fuel is mixed with air. A gate portion is disposed in a first mold for forming a surface portion of the carburetor block which is open on the downstream side of the intake passage and includes the bottom of the float chamber;
A gate reservoir portion is provided at the tip of the gate portion for molding the protrusion and is located approximately in the center of the surface portion, and a second mold facing the first mold has a gate reservoir portion for molding the protrusion. The present invention is characterized in that a core pin for forming a component insertion hole is arranged to enter into the gate reservoir.

Next, preferred embodiments of the carburetor block and its molding device according to the present invention will be given.
A detailed description will be given below with reference to the accompanying drawings.

2 to 4, reference numeral 30 indicates a mixture body block corresponding to the carburetor block according to the present invention. In this case, the second
The figure is a perspective view of the mixture body block 30 from above, while FIG. 3 is a perspective view of the mixture body block 30 from below. Here, the portion facing upward in FIG. 2 is referred to as upper surface portion A, and the portion facing downward in FIG. 3 is referred to as lower surface portion B, and the same reference numerals as those in FIG. shall indicate the element.

The mixture body block 30 is formed with outer bench lilies 14 and 16 that pass through the mixture body block 30, and a float chamber 32 consisting of a concave portion with an open upper surface A side is formed near these outer bench lilies 14 and 16. is formed. In this case, the float chamber bottom portion 34 that closes the lower side of the float chamber 32 is included in the lower surface portion B. A recess 36 extending vertically and having a substantially U-shaped cross section is formed in the inner wall defining the float chamber 32 .

Furthermore, a protrusion 38 that protrudes vertically downward is formed between the lower ends of the outer bench lilies 14, 16 and the float chamber bottom 34, and inside the protrusion 38, as shown in FIG. A flow valve insertion hole 40 communicates with the recess 36 and is used for inserting components.
is formed.

In addition to the outer bench lilies 14 and 16 and the float chamber 32, the mixture body block 30 has various holes such as flow passage holes and component mounting holes shown in elliptical shapes in FIGS. 2 and 3. part is formed. In this case, in particular, a larger number of holes are formed on the upper surface portion A side than on the lower surface portion B side. For example, the hole formed on the upper surface A side is the hole 4 located between the outer bench lilies 14 and 16.
There are 2,44. On the other hand, cylindrical portions 52, 54, and 56 having holes 46, 48, and 50 communicating with the float chamber 32 are integrally formed in a portion of the wall defining the float chamber 32 that faces the recess 36. .

In addition, when configuring a carburetor using the mixture body block 30, the hole 46
is closed by an oil level window member (not shown), and the holes 48 and 50 are also closed by predetermined members.

Furthermore, the throttle body block 4 is joined to the lower surface B side of the mixture body block 30, and the air horn block 8 is joined to the upper surface A side (see FIG. 1).

Next, a molding apparatus for molding the mixture body block 30 will be explained.

The mixture body block 30 is essentially molded by supplying molten resin into a cavity defined by six molds. As shown in FIG. 5, the six molds have a lower surface part B.
A fixed mold 60 for molding the side, a movable mold 61 for molding the upper surface A side, and a sliding mold 6 for molding the side wall of the mixture body block 30.
2, 63 and two other sliding molds (not shown). That is, the movable mold 61 is configured to be movable forward and backward relative to the fixed mold 60, and the four sliding molds 62, 63, etc. are configured to be movable forward and backward relative to the tips of the fixed mold 60 and the movable mold 61. It is composed of Here, in FIGS. 2 and 5, the mold closing directions of the movable mold 61 and the sliding molds 62, 63 are indicated by arrows C, D, and E, and the mold clamping directions of the two sliding molds (not shown) are indicated. In FIG. 2, arrow F,
Indicated by G. In this case, a cavity 66 having a shape corresponding to the mixture body block 30 is defined by the fixed mold 60, the movable mold 61, the four sliding molds 62, 63, etc.

A nozzle member 68 is fitted into the fixed mold 60, and a gate portion 70 (not shown) constituting a relatively narrow gate is provided at the tip of the nozzle member 68. Note that a molten resin supply channel (not shown) is connected to the nozzle member 68. Further, a hole-shaped gate reservoir 72 is formed on the tip side of the gate portion 70 in the fixed mold 60 . That is, the gate reservoir 72 formed in the fixed mold 60 corresponds to the protrusion 38 of the mixture body block 30. Further, a bench lily protrusion 74 (not shown) for molding the downstream part of the outer bench lily 16 is integrally formed on the fixed mold 60, and similarly, a protrusion 74 (not shown) for molding the downstream part of the outer bench lily 16 is formed integrally with the fixed mold 60. A bench lily protrusion is also formed on the fixed mold 60.

On the other hand, a float chamber protrusion 76 for molding the float chamber 32 is integrally formed on the movable mold 61, and a recess 36 in the float chamber protrusion 76 is formed integrally with the movable mold 61.
A core pin 78 is implanted at a location corresponding to (see FIGS. 2 and 4). The tip of the core pin 78 projects from the float chamber protrusion 76 and is configured to enter into the gate reservoir 72 in the mold clamping state shown in FIG. moreover,
A bench lily protrusion 80 for molding the upstream portions of the outer bench lilies 14 and 16 and a bench lily protrusion (not shown) are formed on the movable mold 61. Furthermore, the hole 4 of the mixture body block 30
Core pins 82 and 84 for molding parts 2 and 44 are implanted in the movable mold 61.

Next, the sliding dies 62, 63 and two sliding dies (not shown) are constructed in a shape corresponding to the side wall portion of the mixture body block 30. For example, a core pin 86 for forming the hole 46 of the mixture body block 30 is implanted in the sliding mold 63. Further, a core pin (not shown) for forming the holes 48 and 50 of the mixture body block 30 is also provided in the sliding mold 63.

In fact, core pins (not shown) other than those described above are implanted in the fixed mold 60, the movable mold 61, the sliding molds 62, 63, and the like.

The carburetor block and its molding device according to the present invention are basically constructed as described above, and the functions and effects thereof will be explained next.

First, when the fixed mold 60, the movable mold 61, the four sliding molds 62, 63, etc. move from the mold open state where they are separated from each other to the mold clamping state, move the movable mold 61 in the direction of arrow C.
The sliding molds 62, 63
etc. in the directions of arrows D, E, F and G to define a cavity 66 shown in FIG. that time,
Bench lily protrusion 74 of fixed type 60 and movable type 61
The bench lily protrusion 80 comes into contact with the core pin 7 .
8 enters the gate reservoir 72. Further, the core pin 86 implanted in the sliding mold 63 comes into contact with the float chamber protrusion 76, and the mixture body block 3
0 holes 42, 44, 48, 50 and core pins 82, 8 for forming the outer bench lily 16
4 and the bench lily protrusion (not shown) reach the predetermined position.

After the cavity 66 is thus defined, molten resin is injected into the cavity 66 through the nozzle member 68 and the gate portion 70 at a predetermined pressure. In this case, since the number of core pins is small and the gate part 70 is provided on the relatively wide open side, the molten resin injected into the cavity 66 easily and reliably spreads over the entire area of the cavity 66. .

After the cavity 66 is filled with the molten resin, the molten resin is cooled and solidified over time to form the mixture body block 30. In this case, the core pin 78 enters into the gate reservoir 72, and as a result, the protrusion 38 is made thinner.
Therefore, the hole-shaped gate reservoir 72 is filled with a relatively small amount of molten resin. Therefore, the solidification rate of the molten resin in the gate reservoir 72 is higher than that of the cavity 6.
It is not particularly slow compared to other parts of 6. That is, since the core pin 78 enters the gate reservoir 72, it is possible to cool and solidify the entire molten resin within the cavity 66, including the gate reservoir 72, at a suitable rate. Furthermore, there is a concern that flow marks may occur at the portion corresponding to the gate reservoir 72, that is, at the protrusion 38 of the mixture body block 30. However, since this protrusion 38 is not related to the connection with the flow path of the throttle body block 4 (see FIG. 1), the protrusion 38
There is no problem even if a flow mark occurs at 8.

After the molten resin is cooled and solidified to form the mixture body block 30, the movable mold 61 and the four sliding molds 62, 63, etc. are moved apart from each other to open the mold. Then, when the molded mixture body block 30 is taken out, the molding process is completed.

The throttle body block 4 is joined to the lower surface B of the mixture body block 30 formed as described above, and the air horn block 8 is joined to the upper surface A, thereby closing the float chamber 32. At this time, a float (not shown) is disposed within the float chamber 32, and a predetermined amount of fuel is supplied into the float chamber 32 by a float valve (not shown) that operates in conjunction with the float. Furthermore, a flow valve (not shown) is provided in the recess 36 of the float chamber 32. This flow valve is opened under predetermined conditions to additionally supply fuel in the float chamber 32 into the main intake passage 10, and is used as an economizer to enrich the air-fuel mixture as necessary. Configure. In this case, the flow valve extends from the air horn block 8 side along the recess 36, and its lower end is inserted into the flow valve insertion hole 40. That is, the core pin 78 reduces the thickness of the protrusion 38 and forms a flow valve insertion hole 40, and this flow valve insertion hole 40 is utilized for mounting the flow valve.

According to the present invention, as described above, since the gate portion is provided at a position corresponding to the substantially central portion of the mixture body block side on the throttle body block side,
The molten resin can be easily injected, and insufficient filling of the molten resin can be avoided. Moreover, a protrusion is formed so as to be in contact with the gate part,
In addition, since the flow valve insertion hole is formed in this protrusion, it is possible to prevent the adverse effects of flow marks, etc. that occur near the gate part, and to use the flow valve insertion hole for mounting the flow valve. You can get the effect that there is.

Although the present invention has been described above with reference to a preferred embodiment, the present invention is not limited to this embodiment. Of course, various improvements and changes in design are possible without departing from the spirit of the present invention, such as being able to be configured to attach various parts other than the Fuller valve.

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional schematic side view of the carburetor main body, Fig. 2 is a perspective view including the upper surface of a mixture body block as a carburetor block according to the present invention, and Fig. 3 is the mixture body of Fig. 2. FIG. 4 is a schematic longitudinal sectional view of the mixture body block shown in FIGS. 2 and 3; FIG. 5 is a schematic sectional view showing the mold portion of the molding apparatus according to the present invention. It is a diagram. 14, 16...Outer bench lily, 30...Mixture body block, 32...Float chamber,
38...Protrusion, 40...Flow valve insertion hole,
60... Fixed type, 61... Movable type, 62, 63...
...Sliding type, 66...Cavity, 70...Gate part, 72...Gate reservoir part, 74...Protrusion for bench lily, 76...Protrusion for float chamber, 78...Core pin, 80...For bench lily Protrusion.

Claims (1)

[Scope of Claims] 1. A float chamber into which fuel is introduced by supplying molten resin through a gate into a cavity defined by a mold, and 1. The fuel is mixed with air and flows through it. In the carburetor block in which the above-mentioned intake passage is molded, the protrusion is formed so that the downstream side of the intake passage is open and faces the gate for introducing molten resin near the center of the surface including the bottom of the float chamber. A carburetor block characterized by a hole for inserting parts formed inside the block. 2. In the block according to claim 1, the carburetor block is composed of a mixture body block into which an intake passage bench lily is molded, and the protrusion having a component insertion hole is connected to the downstream end of the bench lily and the float. A carburetor block formed between the bottom of the chamber and the bottom of the chamber. 3. A molding device equipped with a plurality of molds for molding a block for a carburetor, which has a float chamber into which fuel is introduced and one or more intake passages through which the fuel is mixed with air. A gate portion is disposed in a first mold for molding a surface portion that is open on the downstream side of the intake passage of the block and includes the bottom of the float chamber, and a gate portion is provided at the tip of the gate portion at a substantially central portion of the surface portion. A gate reservoir is provided for molding the protrusion, and a second mold facing the first mold is provided with a core pin for forming a component insertion hole that enters into the gate reservoir when the mold is clamped. What is claimed is: 1. A carburetor block molding device, characterized in that it is configured to