JPH043891B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for forming holes in a molded product, and more particularly, the present invention relates to a method and apparatus for forming holes in a molded product, and more particularly, it is possible to form a plurality of holes with a single core pin in injection molding, casting, etc. The present invention relates to a method for forming a forming hole and a forming apparatus.

2. Description of the Related Art In general, a carburetor that applies the principle of atomization is employed as a fuel supply device for automobile engines and the like. in this case,
The gear brector uses the high-velocity airflow generated during the engine's intake process 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. At this time, the piston is pressed by the expansion force within the cylinder, that is, the explosion pressure of the fuel, and the pressing force is converted into rotational force by a crank connected to the piston.

For this reason, it is common for the carburetor main body to be formed with passages such as intake passages, as well as valves and other parts mounting portions. Therefore, the carburetor body has come to be integrally molded from metal, such as zinc or aluminum alloy, because it usually has a complex shape. That is, the carburetor main body is generally cast by die-casting, and then holes for mounting parts and holes for passage are formed, and surfaces for mating with other parts are formed by cutting.

On the other hand, in automobile engines, etc., it is desirable to reduce the weight of the engine in order to improve fuel efficiency, but when the carburetor body is traditionally made of metal, even if the type of metal is changed, the weight reduction will not be possible. There was a limit. Therefore, in recent years, attempts have been made to construct the carburetor body using so-called engineering plastics. In other words, by using a lightweight synthetic resin that has excellent heat resistance, rigidity, and corrosion resistance against fuel as the constituent material of the carburetor body, we aim to reduce the weight of the carburetor body and improve its durability.

Next, a carburetor body made of the above-mentioned synthetic resin will be explained.

In FIG. 1, reference numeral 2 indicates a carburetor body. This carburetor body 2 consists of a throttle body block 4 and a mixture body block 6.
and an air horn block 8, and the blocks 4, 6, and 8 are connected in a stacked state as shown in the figure. In this case, the slotted 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.

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, the main intake path 1
An outer bench lily 1 is installed in the mixture body block 6 at the intermediate portion of each of the 0 and secondary intake passages 12.
4 and 16 are formed. An inner bench lily 1 is provided upstream of the outer bench lilies 14 and 16.
8 and 20 are arranged. A choke valve 22 is pivotally supported on the main intake passage 10 of the air horn block 8, and throttle valves 24 and 26 are pivotally supported on the main intake passage 10 and the secondary intake passage 12 of the throttle body block 4. That is, when the carburetor main body 2 is used, fuel is mixed with air and sucked into a cylinder (not shown) through the flow path defined by the outer bench lilies 14, 16 and the inner bench lilies 18, 20. It turns out.

Incidentally, it is necessary to form various holes in the mixture body block 6 in addition to the outer bench lilies 14 and 16. For example, a first negative pressure hole 30 is formed that communicates with the outer bench lily 14 from the tip end surface of the protrusion 28 formed on the outer wall of the mixture body block 6, and a first negative pressure hole 30 is formed in the inner side of the mixture body block 6. is the first negative pressure hole 3
Extending on the extension line of 0 and outer bench lily 1
4 and 16 must be formed. Therefore, the manufacturing process according to the prior art for creating such a miscast body block 6 will be described next.

The mixture body block 6 itself is essentially injection molded, and a mold portion of the molding apparatus is shown in FIG. In addition, in the mold part shown in FIG. 2, the mixture body block 6 shown in FIG. 1 is molded in an inverted state.
That is, a fixed mold 34 for molding the throttle body block 4 side of the mixture body block 6, a movable mold 36 for molding the air horn block 8 side, and a side wall portion of the mixture body block 6. a sliding mold 38a for molding;
38b and two other sliding molds (not shown) define a cavity 40 having a shape corresponding to the mixture body block 6. In this case, in order to mold the outer bench lilies 14, 16, the bench lily protrusions 41, 42 are integrally formed on the fixed mold 34, and the bench lily protrusions 41, 42 are integrally formed on the movable mold 36 during mold clamping. Bench lily protrusions 43 and 44 that come into contact with 42 are formed. Further, a hole 48 having a shape corresponding to the protrusion 28 of the mixture body block 6 is formed in the sliding mold 38a, and a core pin 50 for forming the first negative pressure hole 30 is inserted into the hole 48. ing. Note that the tip of the core pin 50 comes into contact with the bench lily protrusion 43 during mold clamping.

When injection molding the mixture body block 6, the mold is clamped to the state shown in FIG. 2, and then molten resin is filled into the cavity 40 through a flow path (not shown). The filled resin is cooled and solidified over time to form the mixture body block 6. Thereafter, by opening the mold and releasing the mixture body block 6, the mixture body block 6 having the outer bench lilies 14, 16 and the first negative pressure hole 30 is obtained.

Next, a second negative pressure hole 32 is bored by inserting a drill into the first negative pressure hole 30 from the outside of the mixture body block 6. Thus, in order to manufacture the mixture body block 6, it is necessary to carry out machining to form the second negative pressure hole 32 after injection molding.

However, as described above, the second negative pressure hole 32
The work of drilling itself is complicated, and since the drilling work is required, the manufacturing time of the mixer body block 6 must be relatively long, which is extremely disadvantageous in terms of manufacturing costs. There are inconveniences. Therefore, in order to omit the drilling process of the second negative pressure hole 32 after injection molding, it is desirable to form the second negative pressure hole 32 during the injection molding process. In this case, the first negative pressure hole 30 and the second negative pressure hole 3
2 extends on a straight line, so if we pay attention to this only, it is possible to extend the core pin 50 and provide a long core pin corresponding to the first negative pressure hole 30 and the second negative pressure hole 32. It will be done.

However, in reality, since the bench lily protrusion 43 is located toward the tip of the core pin 50, it is not possible to provide a core pin for forming the second negative pressure hole 32, and as a result, the above-mentioned problem occurs. Drilling is required.

That is, according to the prior art, the first negative pressure hole 30
It has been impossible to mold a plurality of holes that extend intermittently, such as the positional relationship between the second negative pressure hole 32 and the second negative pressure hole 32, in an injection molding process. For this reason, the number of processing steps after injection molding inevitably increases, and the above-mentioned disadvantages are exposed.

The present invention has been made in order to overcome the above-mentioned disadvantages, and among two molds to be combined, a through hole for inserting a core pin provided in one mold is formed in the other mold. By forming the hole by the tip end side of the core pin protruding from the through hole, the drilling work as post-processing that was conventionally required can be omitted, and as a result,
It is an object of the present invention to provide a method for forming a forming hole and a forming apparatus, which facilitate the production of a molded product, shorten the production time, and reduce the production cost.

In order to achieve the above object, the present invention provides a first mold including a core pin for forming a hole whose tip end has a small diameter and whose base side has a larger diameter than the tip end, and a through hole through which the core pin can be inserted. A molded product having a first molding hole and a second molding hole located on an extension line of the first molding hole using a plurality of molds including a second mold in which a protrusion having a protrusion is formed. When molding the first
By bringing the mold and the second mold closer together, the core pin is inserted into the through hole so that the tip end side of the core pin protrudes from the protrusion, and then the mold is clamped to define a cavity for the molded product. completed, and furthermore,
Molten metal is supplied into the cavity, and after the molten metal has solidified, the first mold and the second mold are separated, the core pin is removed from the through hole, the mold is opened, and the molded product is made into a single molded product. A feature is that a single core pin forms a plurality of molded holes with different diameters.

Further, the present invention provides a molded product by defining a cavity for a molded product using a plurality of molds including a first mold and a second mold, and supplying molten metal into the cavity. In a device that molds
A core pin for forming a hole, which is configured such that at least one of the first mold and the second mold can be moved forward and backward relative to the other, and has a tip portion with a small diameter and a root portion with a larger diameter than the small diameter. is disposed in the first mold, a protrusion having a through hole through which the core pin can be inserted is formed in the second mold, and the through hole formed in the protrusion of the second mold is a second mold. One part of the mold is formed so that its diameter is larger than other parts, and when the mold is clamped, the tip end of the core pin is inserted into the through hole and protruded from the protrusion into the cavity. and at least both ends of the through hole are in close contact with each other, and when the core pin is removed from the through hole when the mold is opened, at least two or more holes of different sizes and diameters are formed with a single core pin. Features.

Next, the method for forming a forming hole according to the present invention will be described in detail below with reference to the accompanying drawings, with reference to preferred embodiments in relation to a forming apparatus for carrying out the method.

In the following description, the same reference numerals as those related to the prior art described above indicate the same components.

In FIGS. 3 and 4, reference numeral 60 designates a molding device according to the invention. This molding device 60
This is an apparatus for injection molding a mixture body block 6 as a carburetor block. Note that FIG. 3 shows the mold clamping state of the molding device 60,
FIG. 4 shows the mold opening state of the molding device 60.

The molding device 60 includes a fixing section 62 and the fixing section 62.
The fixed part 62 includes a fixed mold 34, while the movable part 64
is a movable mold 68 and sliding molds 70a, 38b, 38
c, 38d (see Figure 5). In this case, a molded product cavity 72 having a shape corresponding to the mixture body block 6 is defined by all the molds, that is, the fixed mold 34, the movable mold 68, and the sliding molds 70a, 38b to 38d.

A hole 76 with a step is formed in the center of a fixed plate 74 constituting the fixed part 62, and the fixed plate 74 is fixed at a predetermined position. An adapter 80 having a hole 78 formed in the hole 76 is attached to a bolt 82.
A nozzle member 84 is fixed in the hole 78.
is inserted. A molten metal supply channel (not shown) is connected to this nozzle member 84. Furthermore, fixed plate 7
4 is joined to a plate 88 having a hole 86 into which the nozzle member 84 is loosely fitted, and a ring member 90 is fitted to the nozzle member 84. The nozzle member 84
The fixed mold 34 is fitted into the ring member 90,
In this case, a flow path (not shown) within the nozzle member 84 communicates with the cavity 72 . In addition, the plate body 88
A hole 94 for holding the fixed mold 34 in a fitted state is formed in the engaging body 92 adjacent to the hole 94, and inclined rods 96a and 96b are formed around the hole 94.
and two inclined rods (not shown) are planted.
The inclined rod 96a is relatively long, and the inclined rods 96a, 96b and two inclined rods (not shown) are arranged so as to face the movable portion 64 and expand in four directions. Further, the green end of the engaging body 92 has protrusions 98a, 9 that protrude toward the movable part 64.
8b is formed, and these protrusions 98a, 9
Engagement members 102a and 102b having sloped portions 100a and 100b parallel to the sloped rods 96a and 96b are fixed to the inside of the rods 8b. Similarly, an engaging member (not shown) having an inclined surface portion parallel to the two inclined rods (not shown) is disposed near the two inclined rods (not shown). Note that the fixed platen 74, plate body 88, and plate body 92 are integrated by using bolts 104.

The fixed part 62 is constructed as described above, and the movable part 64 will be explained next.

A movable plate 106 constituting the movable part 64 is parallel to the fixed plate 74, and has a relatively large recess 108 formed in its center, and one end into which the tip of the inclined rod 96a enters when tightening. Recess 10
9 is formed. Further, a first cylinder mechanism (not shown) is connected to the movable platen 106, thereby making the entire movable part 64 movable forward and backward relative to the fixed part 62. Further, the recess 108
There is an extrusion mechanism 1 for releasing the mixture body block 6 molded within the cavity 72.
10 are arranged. That is, the extrusion mechanism 110 includes an extrusion plate 114 connected using bolts 112.
a, 114b, and a second cylinder mechanism (not shown) is connected to the extrusion plate 114a so that the extrusion plates 114a, 114b can be displaced along a guide rod 116 whose one end is fitted to the movable platen 106. do. In this case, a plurality of extrusion pins 118 are substantially implanted in the extrusion plate 114b so that they can be inserted into the mold holding member and the movable mold 68 to be inserted into the cavity 72, which will be described later.

Further, a mold holding member 112 is fixed to the movable platen 106, and the other end of the guide rod 116 is fitted into this mold holding member 122. A recess 124 is formed in the center of the mold holding member 122, and a movable mold 68 is inserted into the recess 124 using a bolt 126.
is fixed. Furthermore, the mold holding member 122 has a recess 128 into which the inclined rods 96a and 96b enter.
a and 128b, and a recess (not shown) into which the two not-shown inclined rods enter is also formed.

Furthermore, as shown in FIG.
L-shaped guide books 130a to 130b are fixed to the four corner portions of 2. Sliding molds 70a, 38b to 38d are fitted between these guide blocks 130a to 130d.

On the other hand, the sliding mold 70a is constructed by integrating a mold base 132a, a mold tip 134a, and a core pin 135. And other sliding molds 38b, 38
Similarly, mold bases 132b, 132c,
132d, mold tip 134b, 134c, 134
d and a core pin (not shown). The mold bases 132a to 132d are provided with inclined rods 9.
6a, 96b and two inclined rods (not shown) slidably pass through the inclined holes 136a to 13.
6d is drilled. Furthermore, the mold bases 132a to 132d are provided with inclined surfaces 100a and 100a of the fixing portion 62.
Slope portions 138a to 138d are formed parallel to 00b and other slope portions (not shown).

Next, the mold portions involved in molding the first negative pressure hole 30 and the second negative pressure hole 32 (see FIG. 1) of the mixture body block 6 will be described.

FIG. 6 shows a cross section of a substantially central portion of the molding device 60 shown in FIG. 3, and defines a cavity 72 corresponding to the inverted state of the mixture body block 6 shown in FIG. 1. In this case, in order to mold the outer bench lilies 14 and 16, the fixed mold 34 is provided with the bench lily projections 41 and 42, and the movable mold 68 is provided with the bench lily projections 14 and 16.
4,44 are provided. Furthermore, a sliding mold 70a for molding the side wall portion of the mixture body block 6,
38b to 38d are also formed in a predetermined shape, and in the sliding mold 70a, the mixture body block 6
A hole 48 corresponding to the protrusion 28 is formed. Furthermore, the core pin 13 incorporated in the sliding mold 70a
In No. 5, columnar portions 151 and 152 are integrally formed following the base portion 150 so that the diameter decreases stepwise from the base portion 150 toward the tip side, and a tapered portion 153 is provided at the tip of the columnar portion 152. provided. Further, a columnar section 154, a tapered section 155, and a columnar section 156 are sequentially formed following this tapered section 153 (see FIGS. 6 and 7).

On the other hand, the bench lily protrusion 144 of the movable mold 68 includes the columnar part 152 of the core pin 135 and the tapered part 15.
A through hole 158 is drilled through which the portion consisting of the columnar portion 154 and the columnar portion 154 is inserted during mold clamping. As shown in FIG. 7, this through hole 158 is configured by sequentially communicating with a circular hole portion 160 that is in close contact with the columnar portion 152, a tapered hole portion, and a circular hole portion 162 that is in close contact with the columnar portion 154. ing.

The molding apparatus for carrying out the method of the present invention is basically constructed as described above, and then:
The action and effect will be explained.

First, when clamping the mold from the mold open state shown in FIG.
4 to the fixed part 62 side. As a result, the inclined rods 96a, 96b and two inclined rods (not shown) are inserted into the inclined holes 136a to 136d formed in the sliding molds 70a, 38b to 38d. In this way, the four inclined rods (96
a, 96b, etc.) are inclined hole portions 136a to 136d.
By being inserted into the sliding mold 70a, 38
d to 38d are four inclined rods (96a, 96
b etc.) and is displaced toward the movable mold 68 side. At this time, the sliding molds 70a, 38b to 38d are guided and slid by the mold holding member 122 and the guide blocks 130a to 130d. Further, when the movable part 64 approaches the fixed part 62 side, the engaging member 102a provided on the engaging body 92, 102
b and two engaging members (not shown) come into sliding contact.
With this, the sliding molds 70a, 38b to 38d
is strongly pressed in the mold clamping direction, and the bench lily protrusions 144, 44 of the movable part 68 come into pressure contact with the bench lily protrusions 41, 42 of the fixed mold 34, and the mold is clamped.

In addition, during mold clamping, the core pin 135 that is displaced in the mold clamping direction is inserted into the through hole 158 formed in the movable mold 68, and the columnar part 156 at the tip of the core pin 135 is inserted into the bench lily protrusion 144 of the movable mold 68.
comes into contact with. When the core pin 135 is inserted into the through hole 158 in this way, the tip end of the core pin 135 has a relatively small diameter and is provided with the tapered portion 155, so the tip end side of the core pin 135 is locked in the through hole 158. It can be easily inserted without being damaged. Moreover, as shown in FIG.
In No. 8, since the tapered hole portion 161 is formed between the circular hole portion 160 and the circular hole portion 162 having different diameters, the core pin 135 can be inserted into the through hole 158 even more smoothly. Also, core pin 13
The portion corresponding to the through hole 158 of No. 5 and the through hole 1
58 does not have a uniform diameter throughout, but the diameter is changed appropriately to form the core pin 135 and the through hole 15.
The structure is such that the number of contact parts with 8 is relatively small. That is, the core pin 135 and the movable mold 6
8 are separated from each other in a portion corresponding to the distance A shown in FIG. 7, and are in close contact with each other at both ends of the through hole 158. As a result, when the core pin 135 is inserted into the through hole 158, the frictional resistance between the core pin 135 and the movable mold 68 is relatively small, so that the core pin 135 can be easily inserted into the through hole 158. Become.

After the mold is clamped to the state shown in FIGS. 3 and 6, molten metal, that is, molten resin, is injected into the cavity 72 at a predetermined pressure through the nozzle member 84. The above-mentioned resin is heat-resistant, such as polyphenylene sulfide (PPS), which can obtain extremely high strength and rigidity by mixing glass fiber, etc., and also has excellent heat resistance and dimensional stability. It is preferable to use flexible engineering plastics.

The molten resin filled in the cavity 72 solidifies as the temperature decreases, and becomes a molded product corresponding to the shape of the cavity 72, that is, the mixture body block 6.

Next, when opening the mold, the movable part 64 is separated from the fixed part 62 and displaced to the initial mold opening position. As a result, the movable mold 68 is moved to the fixed mold 34.
4 inclined rods (96
a, 96b, etc.) and inclined hole portions 136a to 136d.
Sliding molds 70a, 38b to 38 are provided below for sliding action with
d are displaced in the mold opening direction so as to be separated from each other, and at this time, the core pin 135 is removed from the through hole 158 of the movable mold 68. In this way, the first negative pressure hole 30 is formed by the columnar parts 151 and 152 of the core pin 135, and the columnar part 154 and the tapered part 1
55, the second negative pressure hole 32 is formed by the columnar portion 156.

After the mold is opened, the mixture body block 6 that is in close contact with the movable part 68 is moved to the extrusion mechanism 110.
(See Figure 3) to release the mold. That is,
By driving a second cylinder mechanism (not shown) connected to the extrusion plate 114a, the extrusion plate 114a,
114b is displaced along guide rod 166. As a result, the extrusion pin 118, which is implanted in the extrusion plate 114b and whose tip reaches the end surface of the movable mold 68, pushes the mixture body block 6 toward the fixed part 62 side. Then, a mixture body block 6 in which the first negative pressure hole 30 and the second negative pressure hole 32 are formed is formed.
When the molding device 60 is taken out, the molding process is completed.

According to the present invention, as described above, in order to insert the core pin provided in a predetermined mold into the through hole bored in another mold, the tip end side of the core pin protruding from the through hole is inserted. Furthermore, it is possible to form a forming hole by using the other end of the core pin that does not reach the through hole. That is, two molding holes can be molded at once using a single core pin. Further, since a gap is partially provided between the inner circumferential surface of the through hole and the core pin, the core pin is less likely to slide on the inner circumferential surface of the through hole, so that the core pin can be easily displaced. Therefore, the conventional drilling work required in the post-processing process can be omitted, thereby simplifying the manufacturing process of the formed product. Moreover,
As a result, since the number of processing steps is reduced, it is possible to shorten the manufacturing time of the product, resulting in the effect that manufacturing costs can be reduced.

Although this example describes plastic molding using molten resin, it is also possible to mold multiple cast holes using a single core pin in a casting process using molten metal. It will be easily understood.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments. For example, even when manufacturing products other than mixture body blocks, similar methods can be used. It goes without saying that various improvements and changes in design are possible without departing from the gist of the present invention, such as being able to form a molding hole using a device.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of the carburetor body, FIG. 2 is a partially omitted sectional view of a mold portion of a molding device according to the prior art, and FIG. 3 is a cross-sectional view of the molding device according to the present invention showing the mold clamped state. FIG. 4 is a partially omitted sectional view showing the mold opening state of the molding apparatus according to the present invention, and FIG.
The figure is a plan view of the movable part of the molding apparatus according to the present invention showing the mold clamping state with the fixed part omitted, FIG. It is an explanatory view showing a part of the figure enlarged. 6...Mixture body block, 30, 32
... Negative pressure hole, 34 ... Fixed type, 38a to 38d...
...Sliding mold, 60... Molding device, 62... Fixed part,
64... Movable part, 68... Movable type, 70a... Sliding type, 72... Cavity, 135... Core pin, 158... Through hole.

Claims (1)

[Scope of Claims] 1. A first mold including a hole forming core pin whose tip end has a small diameter and whose base side has a larger diameter than the tip end, and a protrusion having a through hole through which the core pin can be inserted. When molding a molded product having a first molding hole and a second molding hole located on an extension line of the first molding hole using a plurality of molds including a second mold having a molded shape,
By bringing the first mold and the second mold close to each other, the core pin is inserted into the through hole so that the tip end of the core pin protrudes from the protrusion, and then the molds are clamped to form a molded product. defining a cavity; further supplying molten metal into the cavity;
After the molten metal has solidified, the first mold and the second mold are separated, the core pin is removed from the through hole, the mold is opened, and a single core pin is used to form a molded product with a plurality of diameters. A method for forming a forming hole characterized by forming different forming holes. 2. In the method described in claim 1,
The molded product consists of a carburetor block that makes up the carburetor body, and a method for forming holes. 3. In an apparatus for forming a molded product by defining a cavity for a molded product using a plurality of molds including a first mold and a second mold, and supplying molten metal into the cavity. , at least one of the first mold and the second mold is configured to be movable forward and backward relative to the other, and the hole is formed such that the tip part has a small diameter and the root part has a larger diameter than the small diameter part. A core pin for use is disposed in the first mold, a protrusion having a through hole through which the core pin can be inserted is formed in the second mold, and a through hole is formed in the protrusion of the second mold. is formed so that the diameter of the portion on the first mold side is larger than that of other portions, and when the mold is clamped, the tip end side of the core pin is inserted into the through hole and protrudes from the protrusion into the cavity. The core pin and at least both ends of the through hole are brought into close contact with each other, and the core pin is removed from the through hole when the mold is opened, thereby forming at least two or more holes of different sizes and diameters with a single core pin. A molding device characterized by: