JP2000167872A - Manufacture of intake member made of resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding a throttle body for an engine calling for high dimensional precision in resin. SOLUTION: The throttle body 1 is constituted of an inner body part 2 made of resin, an accessory part 3 made of resin molded integrally with the outer periphery of the body part 2 and a pipe material 4 for antiicing imbedded in the accessory part 3. In a primary molding step, the generation of a molding sink and a warpage is suppressed and the roundness of the inner peripheral face of the body part 2 is secured by molding a cylindrical body part 2 with almost a uniform wall thickness. In the consecutive secondary molding step, the throttle body 1 of a desired shape is obtained by molding the accessory part 3 in such a way as to cover the outer lateral part of the body part 2. In addition, the body part 2 and the accessory part 3 fit well with each other so that their easy integration is realized by using the same kind of resin material in the primary and the secondary molding processes. Further it is possible to enhance the roundness of the body part 2 more than ever and also simplify an injection molding device so that equipment cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resin-made air-intake member by injection molding a resin-made air-intake member having a substantially cylindrical main body and an attachment part integrally connected to the outer periphery of the main body.

[0002]

2. Description of the Related Art A method of injection molding a mixture body block of a carburetor, which is an intake member of an engine, with resin has been proposed in Japanese Patent Application Laid-Open No. 62-196115.

[0003]

Incidentally, members such as the above-mentioned mixture body blocks are not required to have such high dimensional accuracy, so that it is generally possible to mold them with a resin whose dimensional accuracy is inferior to metal. . However, for example, the inner peripheral surface of a member such as a throttle body, which is an intake member of the engine, has a sufficient influence on the idling performance of the engine because the gap between the inner peripheral surface of the throttle valve housed therein and the rotating member greatly affects the idling performance of the engine. It is necessary to ensure high dimensional accuracy.

[0004] The present invention has been made in view of the above circumstances, and has as its object to provide a method for molding an intake member of an engine, which requires high dimensional accuracy, with resin.

[0005]

In order to achieve the above object, an invention according to a first aspect of the present invention is directed to an air intake system having a substantially cylindrical main body and an auxiliary part integrally connected to an outer periphery of the main body. In the method for manufacturing a resin-made intake member in which a member is injection-molded with a resin, after the main body is primarily molded with a primary molding die, the main body is inserted into a secondary molding die and integrally with the main body. The attachment portion is formed by secondary molding, and the same resin material is used for the main body portion and the attachment portion.

According to the above construction, the main body to be primarily formed is substantially cylindrical, and there is no great difference in the thickness of each part. Therefore, sinks and warpage generated during cooling are minimized to minimize roundness. A high body can be molded. In addition, since the accessory part integrally connected to the outer periphery of the main body is formed by the secondary molding following the primary molding, a resin intake member having a desired shape can be finally obtained. In addition, since the same type of resin material is used for the main body part to be primary molded and the auxiliary part to be secondary molded, the main body part and the auxiliary part are well integrated and easily integrated, further improving the roundness of the main body part. Enhanced. In addition, since only one kind of resin material needs to be injected, the injection molding apparatus can be simplified and the equipment cost can be reduced.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the resin material is a super engineering plastic or a general engineering plastic.

[0008] According to the above-described structure, the super engineering plastics, which improve the dimensional accuracy of the product but are expensive, and the general-purpose engineering plastics, which have the dimensional accuracy of the product slightly lower but are inexpensive, are used separately, so that the performance and the cost can be given priority. It can be selected freely according to

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 10 show a first embodiment of the present invention. FIG. 1 is a view showing the shape of a throttle body in each step, and FIG. 2 is a horizontal view of a throttle body forming die showing a primary forming step. FIG. 3 is a sectional view (a sectional view taken along line 2-2 in FIG. 3)
2 is a sectional view taken along the line 3-3 in FIG. 2, FIG. 4 is an explanatory view corresponding to FIG. 3, FIG. 5 is an enlarged view taken along the line 5-5 in FIG. 2, and FIG. 7 is a cross-sectional view taken along line 6-6 of FIG. 7, FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6, FIG. 8 is an explanatory view corresponding to FIG. 7, and FIG.
FIG. 10 is a graph showing the roundness of the main body of the throttle body, as viewed from an arrow -9 line.

First, a throttle body 1 as a resin intake member formed by the method of the present invention based on FIG.
The structure of will be described. As shown in FIG. 1 (C), the throttle body 1 includes an inner body 2, an attachment 3 integrally formed on the outer periphery of the body 2, and an attachment 3 supported on the outer periphery of the body 2. And a copper pipe member 4 for preventing icing to be buried therein.

[0012] As shown in FIG. 1 (A), a cylindrical portion 2 ₁ formed in the cylindrical body portion 2 made of resin having a slight taper, formed integrally with one axial end of the cylindrical portion 2 ₁ the flange portion 2 ₂ coupled to the engine body is a cylindrical portion 2
A pair of bosses 2 ₃ , 2 ₃ integrally projecting from the outer peripheral surface of ₁
And The flange portion 2 ₂ O-ring annular groove 2 ₄ to be fitted is formed on an outer peripheral surface of the cylindrical portion 2 ₁ a plurality of locking projections 2 ₅ ... it is formed. Circular throttle valve housed in the cylindrical portion 2 ₁ 5, boss 2 ₃ the shank 6,
Is supported on 2 ₃ driven to be opened and closed by a throttle actuator, not shown. The main body 2 is injection molded by a primary molding die in a primary molding step. At least the cylindrical portion 2 ₁ of the vicinity of the throttle valve 5 is formed into a straight shape without a taper.

As shown in FIG. 1B, in a pipe material setting step following the primary forming step, the cylindrical portion 2 of the main body 2 is formed.
_The pipe member 4 is temporarily supported by a plurality of locking projections 2 ₅ projecting from ₁ .

As shown in FIG. 1 (C), the resin attachment 3 is injection-molded by a secondary molding die in a secondary molding step following the pipe material setting step.
In addition to the pipe material burying portion for burying the above, an air passage portion, a reinforcing portion, a cord support portion, a main body attaching portion and the like are integrally provided, and are integrally formed so as to cover the outer periphery of the main body portion 2.

Next, the structure of the throttle body molding die will be described with reference to FIGS.

The mold for forming the throttle body is a fixed side plate 11.
And an arrow A with a driving source (not shown) with respect to the fixed side plate 11.
And a movable side plate 12 movable in the −A ′ direction. A pair of upper and lower slide guides 13 and 14 are fixed to the movable side plate 12, and a slider 15 is slidably supported between the slide guides 13 and 14. The slider 15
Output rod 16 of cylinder 16 fixed to movable side plate 12
a and slides in the direction of arrow BB 'in FIG. Then, as shown in FIG. 2, when the cylinder 16 contracts, the slider 15 stops at the primary molding position, and as shown in FIG. 6, when the cylinder 16 extends, the slider 15 stops at the secondary molding position. I do.

The slider 15 faces the fixed side plate 11 side.
A protruding substantially cylindrical movable core 23 is fixed. Also
Guide rail 1 provided vertically above movable side plate 12
2a, the upper slide core 24 for primary molding₁And secondary
Upper slide core 24 for molding _TwoCan slide up and down freely
While being installed vertically below the movable side plate 12.
The lower guide for primary molding is attached to the guide rail 12b.
A25₁And lower slide core 25 for secondary molding_TwoIs on
It is slidably supported below.

Therefore, the upper slide core 24 for primary molding is used.
₁ and the secondary molding upper slide core 24 ₂ is lifting simultaneously, likewise the primary molding lower slide core 25 ₁ and the secondary molding lower slide core 25 ₂ is lift simultaneously.
The core pin 26 ₁ is attached to the upper molding core 24 ₁ for primary molding.
Are provided, and a core pin 27 ₁ is provided on the lower slide core 25 ₁ for primary molding. The core pin 26 ₂ is provided in the secondary molding upper slide core 24 _2, core pin 27 ₂ is provided at the secondary molding lower slide core 25 _2.

The fixed side plate 11 is provided at a position facing the movable core 23 at the primary molding position or the secondary molding position, at a position where the primary molding fixed core 28 ₁ and the secondary molding fixed core 28 _{2 are located.}
Is provided. The fixed side plate 11 has four inclined pins 29 ₁ , 2 that expand in a vertical U-shape toward the movable side plate 12.
9 _2; 30 _1, 30 ₂ are fixed, of which two inclined pins 29 _1, 30 _1, the primary molding upper slide core 24 ₁ and the lower slide core 25 ₁ for primary molding slidably Penetrate and the remaining two inclined pins 2
9 _2, 30 _2, through the secondary molding upper slide core 24 ₂ and the secondary molding lower slide core 25 ₂ slidably. When the mold is clamped, the inclined pins 29 ₁ , 29 ₂ ; 30 ₁ ,
In order to avoid interference with the 30 _second tip 4 on the movable side plate 12
The concave portions 12c, 12d, 12e, and 12f are formed.

Thus, when the movable core 23 is at the primary molding position shown in FIGS. 2 and 3, the movable core 23, the primary molding upper slide core 24 ₁ , the primary molding lower slide core 25 _1, and the primary molding by the primary molding die D ₁ consisting use stationary core 28 _1, the throttle body 1 main body 2
The primary molding cavity C ₁ for molding is formed the. When the movable core 23 is in the secondary molding position shown in FIGS. 6 and 7, the movable core 23, the secondary molding upper slide core 24 ₂ , the secondary molding lower slide core 25 _2, and the secondary molding fixed a core 28 ₂ secondary molding die D ₂
The secondary molding cavity C ₂ for molding the appendage 3 of the throttle body 1 is formed.

The movable core 23 and the primary molding fixed core 28 ₁
Opposing the disk gate 31 leading to the entire area of the one end of the primary molding cavity C ₁ is formed on the surface, the runner 32 extending through the fixed plate 11 and the stationary core 28 ₁ for primary molding in the center of the disk gate 31 and It is connected. A runner plate 33 is superimposed on the back surface of the fixed side plate 11 so as to be able to approach and separate therefrom.
A runner 35 is formed on the fixed side plate 11 facing the runner 3. Also are the two runners 36 and 36 connected to one end of the secondary molding cavity C ₂ penetrates the fixed side plate 11 and the stationary core 28 ₁ for primary molding, the runner 37 communicating with the runner 36 and 36
Are formed on the fixed side plate 11 facing the runner plate 33.

As shown in FIG. 5 and FIG.
A switching valve 38 for distributing the molten resin to the primary molding cavity C ₁ and the secondary molding cavity C ₂ is provided at a portion facing the first runner plate 33. Switching valve 31
Has a first spool 40 that slides by a rod 39 and a second spool 42 that slides by a rod 41. The first and second spools 40 and 42 are moved in opposite directions by a drive source (not shown). Driven.

When the switching valve 38 is in the primary molding position shown in FIG.
Is connected to the runner 35 connected to the primary molding cavity C ₁ through the groove 40 a of the first spool 40,
And it is cut off from the runner 37 communicating with the secondary molding cavity C ₂ by the land 42b of the second spool 42.
When the switching valve 38 is at the secondary molding position shown in FIG.
Sprue 43, a runner 37 communicating with the cavity C ₂ for secondary molding through the groove 42a of the second spool 42
It is connected to, and is isolated from the runner 35 communicating with the primary molding cavity C ₁ by the land 40b of the first spool 40.

Next, the operation of the embodiment of the present invention will be described.

First, in the primary forming step, as shown in FIGS. 2 and 3, the cylinder 16 is contracted to
By moving the movable side plate 12 to the fixed side plate 11 while the first molding die D is stopped at the primary molding position, the primary molding die D
₁ movable core 23, upper slide core 2 for primary molding
4 _1, for clamping the lower slide core 25 ₁ and the stationary core 28 ₁ for primary molding primary molding. At this time, the switching valve 3
8 is in the state shown in FIG. 5, the molten resin supplied from the sprue 43 is supplied to the groove 40a, the runner 35, the runner 32 and through the disk gate 31 primary molding cavity C ₁ of the first spool 40, Fig. 1 The main body 2 of the throttle body 1 shown in FIG.

The main body formed in the primary forming step
The part 2 is substantially cylindrical and the thickness of each part is uniform.
It minimizes sinks and warpage during rejection.
The inner peripheral surface of the main body 2 where dimensional accuracy is required
It can be formed into a perfect circle. Also disk-shaped disk
Primary molding cavity C through gate 31₁All over
Since the molten resin can be supplied uniformly, the molten resin
To prevent turbulence from occurring in the molten resin
Suppresses filler orientation, enabling more accurate molding
Ability. In addition, the upper slide for primary molding
Docoa 24₁And lower slide core 25 for primary molding₁
Core pins 26 provided respectively₁, 27 ₁By the slot
A pair of bosses 2 supporting the shaft 6 of the throttle valve 5_Three,
2_ThreeTo reduce the number of processing steps by integrally molding
Becomes possible.

When the primary molding step is completed as described above, the movable side plate 12 moves away from the fixed side plate 11 as shown in FIG.
Upper slide core 2 for primary molding guided by ₁ , 30 ₁
4 ₁ and primary molding lower slide core 25 ₁ is separated in the vertical direction, the primary molding die D ₁ is opened mold. In the next pipe material setting step, a plurality of locking projections 2 ₅ protruding from the cylindrical portion 2 ₁ of the main body portion 2 as shown in FIG. 1 (B)
.. Are temporarily supported by the pipe member 4.

Subsequently, when the cylinder 16 is extended and the slider 15 integrated with the movable core 23 moves to the secondary molding position shown in FIGS. 6 and 7, the movable side plate 12 is moved to the fixed side plate 11 again. the secondary molding die D ₂ of the movable core 23, the secondary molding upper slide core 24 ₂ and clamping the lower slide core 25 ₂ and the secondary molding stationary core 28 ₂ for secondary molding. At the time of the mold clamping, the upper slide core for secondary molding 24 ₂ , the lower slide core for secondary molding 2
5 ₂ toward each other by being guided by the inclined pin 29 _2, 30 _2.

At this time, the switching valve 38 is in the state shown in FIG. 9, and the molten resin supplied from the sprue 43 passes through the groove 42a of the second spool 42, the runner 37, and the runners 36, 36 to form the secondary molding cavity C. ₂ and is injection-molded so that the attachment 3 of the throttle body 1 shown in FIG. Then the movable plate 12 is opened moved to the second molding die D ₂ is the mold so away from the fixed plate 11, The molded throttle body 1
Is discharged. Thereafter, the cylinder 16 contracts, the slider 15 returns to the primary molding position shown in FIG. 2, and each cycle of the process is completed.

The same type of resin material is used for the primary molding and the secondary molding described above. That is, the main body 2 and the attachment 3 of the throttle body 1 are formed of the same resin material.

As described above, the main body 2 having a uniform thickness is precisely formed in the primary molding step, and the auxiliary part 3 having a non-uniform thickness is formed in the secondary molding step so as to cover the main body 2. Therefore, the dimensional accuracy of the inner peripheral surface of the main body 2 can be greatly improved as compared with the case where they are formed in a single forming step.

Further, since the same type of resin material is used for the primary molding and the secondary molding, the main body 2 and the attachment 3 are integrated with each other with good familiarity, and the roundness of the inner peripheral surface of the main body 2 is further improved. In addition, since the injection molding device only needs to be capable of injecting one type of molten resin, the structure of the injection molding device can be simplified as compared with a device capable of injecting two types of molten resin for primary molding and secondary molding. Thus, equipment costs can be significantly reduced.

FIG. 10 is a graph showing a perfect circle of the inner diameter of the main body 2 when the throttle body 1 is formed by the method of the present invention (a method of forming the main body 2 and the attachment 3 by primary molding and secondary molding). And the conventional method of forming the throttle body 1 (the method of molding the main body 2 and the attachment 3 in one time)
Is a measurement of the roundness of the inner diameter of the main body 2 in the case where it is molded by the above method. The roundness represents the maximum value of the error of the inner diameter of the main body 2 of the throttle body 1 with respect to a perfect circle. The smaller the value, the higher the accuracy, and the larger the value, the lower the accuracy.

The roundness was measured using various types of resin materials such as general-purpose engineering plastics and super engineering plastics. Among them, three kinds of resin materials, namely, polyamide (PA) resin,
FIG. 10 shows the results when the polybutylene terephthalate (PBT) resin and the polyetherimide (PEI) resin were used. "No mold temperature difference" is the case where the temperature of the whole mold is kept constant, and the temperature is determined according to the type of resin. In the case of "with mold temperature difference", the temperature (the inside temperature) of the portion (movable core 23) facing the inner peripheral surface of the main body 2 of the throttle body 1 is kept lower than the other portions (the outside temperature) of the mold. The temperature is determined according to the type of resin. The temperature of the mold can be controlled by the flow rate of cooling water flowing inside the mold.

As is clear from FIG. 10, in both the case of "without mold temperature difference" and the case of "with mold temperature difference", the conventional one-time molding has low accuracy. Although the precision of the product is slightly reduced as the primary molding and the secondary molding are performed, the accuracy of the final secondary molded product is much higher than that of the conventional single molding. The effect of the resin material on the accuracy is that PA, which is a very inexpensive general-purpose engineering plastic, has low accuracy, and PBT, which is a relatively expensive general-purpose engineering plastic, has much higher accuracy. PEI, which is an expensive super engineering plastic, has the highest accuracy.

Further, as compared with the case of “no mold temperature difference”,
In the case of "there is a mold temperature difference", the accuracy is uniformly improved.
The reason is that the temperature of the movable core 23 that forms the inner peripheral surface of the main body 2 of the throttle body 1 is set lower than the temperature of the other portions, so that the dimensional accuracy of the main body 2 is required.
The reason for this is that the inner peripheral surface can be cooled faster than other portions to prevent the occurrence of sink marks.

If super-engineering plastics (for example, polyetherimide (PEI), polyethersulfone (PES), polyphenylene sulfide (PPS), polyamideimide (PAI), etc.) are used for the injection molding of the throttle body 1, the accuracy can be improved. Although it is very effective in securing, there is a problem that the cost increases. On the other hand, when a general-purpose engineering plastic (for example, polyamide (PA), polyacetal (POM), polybutylene terephthalate (PBT), etc.) is used instead of the super engineering plastic, the dimensional accuracy is slightly reduced, but the cost can be reduced.

Therefore, when dimensional accuracy is important, use the same type of super engineering plastic for primary molding and secondary molding,
When the dimensional accuracy is not so important, the same type of general-purpose engineering plastic of the primary molding and the secondary molding can be used to freely select the specification giving priority to the dimensional accuracy and the specification giving priority to the cost.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment described above, the primary molding die D ₁
And although injecting secondary molding die D ₂ two hours difference with a molten resin, the production efficiency by injecting simultaneously molten resin into the primary molding die D ₁ and the secondary molding die D ₂ in the second embodiment Can be enhanced. Therefore, the movable plate 12 can be intermittently rotated by 180 ° to the axis L direction, and ₁ two movable cores 23, 23 ₂ is provided in the movable side plate 12. The structure of the fixed plate 11 side is substantially the same as the first embodiment, the primary molding die D ₁ and the secondary molding die D
_The switching valve 38 is not provided for simultaneously injecting the molten resin into ₂ .

[0041] In Thus, the primary molding die D ₁ as shown in (A) is empty, the secondary molding die D ₂ in The molded body portion 2
Is supplied to the two dies D ₁ and D ₂ at the same time, thereby performing the primary molding with the primary molding die D ₁ and the secondary molding with the secondary molding die D ₂ .

Subsequently, as shown in (B), the completed throttle body 1 is opened from the secondary molding die D ₂ by opening the mold, and the movable side plate 12 is rotated by 180 ° to obtain (C). the movable core 23 ₁ and the body portion 2 is moved to the secondary molding die D ₂ as shown in. And
After the mold is clamped as shown in (D), the molten resin is simultaneously supplied to both dies D ₁ and D ₂ as shown in (E) to return to the state of (A).

According to this embodiment, one throttle body 1 can be formed for one injection of the molten resin, and the production efficiency is greatly increased.

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, it is also possible to put the primary molding die in the secondary molding die and perform the primary molding and the secondary molding with the same die.

[0046]

As described above, according to the first aspect of the present invention, since the main body to be primarily formed has a substantially cylindrical shape and there is no great difference in the thickness of each part, the sink formed during cooling is reduced. It is possible to form a highly round main body while minimizing warpage. In addition, since the accessory part integrally connected to the outer periphery of the main body is formed by the secondary molding following the primary molding, a resin intake member having a desired shape can be finally obtained. In addition, since the same type of resin material is used for the main body part to be primary molded and the auxiliary part to be secondary molded, the main body part and the auxiliary part are well integrated and easily integrated, further improving the roundness of the main body part. Enhanced. In addition, since only one kind of resin material needs to be injected, the injection molding apparatus can be simplified and the equipment cost can be reduced.

According to the second aspect of the present invention,
By using a super engineering plastic, which improves the dimensional accuracy of the product but is expensive, and a general purpose engineering plastic, which has a slightly lower dimensional accuracy of the product but less expensive, the performance and cost can be freely selected according to the priority. .

[Brief description of the drawings]

FIG. 1 is a view showing the shape of a throttle body in each process.

FIG. 2 is a horizontal cross-sectional view of a throttle body molding die showing a primary molding step (a cross-sectional view taken along line 2-2 in FIG. 3).

FIG. 3 is a sectional view taken along line 3-3 in FIG.

FIG. 4 is an operation explanatory view corresponding to FIG. 3;

FIG. 5 is an enlarged view taken along line 5-5 in FIG. 2;

FIG. 6 is a horizontal cross-sectional view (cross-sectional view taken along line 6-6 in FIG. 7) of the throttle body molding die showing a secondary molding step.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is an operation explanatory view corresponding to FIG. 7;

9 is an enlarged view taken along line 9-9 of FIG. 6;

FIG. 10 is a graph showing the roundness of the main body of the throttle body.

FIG. 11 is a process explanatory view according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Throttle body (intake member) 2 Main part 3 Attached part D ₁ Primary molding die D ₂ Secondary molding die

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoji Yamane 1-10-1 Shinsayama, Sayama-shi, Saitama F-term (reference) in Honda Engineering Co., Ltd. 4F206 AA23 AA29 AA32 AA34 AD12 AH16 JA07 JB12 JN12 JQ81

Claims (2)

[Claims] 1. A resin-made air-intake member for injection-molding an air-intake member (1) having a substantially cylindrical main body (2) and an attachment (3) integrally connected to the outer periphery of the main body (2). In the method for manufacturing a member, after the main body (2) is primarily molded by a primary molding die (D ₁ ), the main body (2) is inserted into a secondary molding die (D ₂ ), and the main body (2) is inserted. A resin intake member characterized in that the accessory part (3) is formed secondarily with the part (2), and the same type of resin material is used for the main body part (2) and the accessory part (3). Manufacturing method. 2. The method according to claim 1, wherein the resin material is a super engineering plastic or a general engineering plastic.