JPH0994851A - Apparatus for injection molding and seal ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity with a relatively simple constitution and without spoiling the function of a seal ring by moving a punch tuntil it reaches the wall face of a cavity after a molten resin is fed in the cavity. SOLUTION: When each plate 1 and 3 is clamped and each parting face is butted and a molten resin P is fed from a sprue 2, the resin P is fed into a guide hole 6 through a runner 4, a submarine gate 8, a connecting part 8a and is furthermore fed into a cavity 5 through the guide hole 6. Then, when the punch 7 is moved toward the cavity 5 until the resin P is cured, the resin P at the connecting part 8a of the guide hole 6 with the submarine gate 8 is cut by means of the punch 7. On the other hand, the resin P filled in the guide hole 6 is pushed by means of the punch 7 and is pressed in the cavity 5. Then, at a stage where the apex face of the punch 7 moves and becomes approximately to coincide with the side wall face of the cavity 5, it is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus and a seal ring, and more particularly to an injection molding of a resin oil seal ring used for sealing hydraulic oil in an automatic transmission such as a torque converter and a hydraulic clutch. Regarding the device.

[0002]

2. Description of the Related Art Generally, an oil seal ring is, for example, A
It is mounted on the torque converter, oil pump, hydraulic clutch, oil distributor, etc. of the automatic transmission of the T car. Normally, this type of seal ring is made by molding cast iron into an end ring shape. However, injection of synthetic resin reflects the tendency of weight reduction of vehicle body and cost reduction. In many cases, molded products are used.

By the way, this seal ring is formed into an end shape in which a part in the circumferential direction is separated in order to facilitate the attachment to the application site, and the separation end has a straight cut type or a composite. A step cut type abutment is formed. When such a seal ring is applied to, for example, a hydraulic control system in an automatic transmission of an AT vehicle, it is known that the outer peripheral surface of the seal ring acts as an extremely important functional part in hydraulic control. . Therefore, when injection molding,
It is devised so that no gate marks remain on the outer peripheral surface.

Conventionally, for example, an injection molding apparatus shown in FIG. 9 is used. In the figure, A is a first plate, and a sprue-B for injecting a molten resin is formed in the center of the first plate. This first
In the second plate B that collides with the plate A, the runner D communicating with the sprue B, the gate E continuous with the runner D, and the gate E continuing with the runner D. A ring-shaped cavity F having an end is formed.

When the molten resin is injected from the sprue-B while the plates A and C are clamped, the resin enters the cavity F through the sprue-B, the runner D and the gate E. Supplied and cured. When these are taken out from the molding apparatus, a seal ring G shown in FIG. 10 is obtained.
Although the sprue B and the runner D are attached to the seal ring G, they are appropriately separated from the gate portion (E).

According to this molding apparatus, since there is no gate mark on the outer peripheral surface of the molded seal ring G, it is applied to the hydraulic control system of an automatic transmission of an AT vehicle as described above. However, although a sufficient function as a seal ring can be achieved, there is a problem in that the amount that can be produced in one molding operation is extremely small and the demand cannot be met.

[0007]

Therefore, in order to solve such a problem, as shown in FIG. 11, a runner and a cavity (seal ring G) are provided on the outer peripheral surface of the seal ring G by side gages. A molding device has been proposed, which is connected by means of a toe (E).

According to this molding apparatus, a large number of seal rings can be taken and productivity can be remarkably enhanced, but a gate is provided on the outer peripheral surface (outer diameter side surface) which is functionally important. Since it is provided, the original function as the seal ring cannot be obtained when the gate mark remains. In this case, post-processing may be performed so that no gate mark remains, but there is a problem that the post-processing requires a large number of man-hours and the cost is high.

Therefore, an object of the present invention is to provide an injection molding apparatus and a seal which can improve the productivity with a relatively simple structure without impairing the function as a seal ring.
To provide a ruling.

[0010]

SUMMARY OF THE INVENTION Therefore, in order to achieve the above-mentioned object, the present invention provides a first plate having a sprue, a runner which communicates with the sprue at the time of collision, and this runner. A ring cavity having an end adjacent to, a guide hole communicating with the side wall surface adjacent to the outer peripheral wall surface of the cavity, a second plate including a submarine gate connecting the runner and the guide hole, and the guide hole. A punch that is movably fitted and arranged is provided, and after the molten resin is supplied to the cavity, the punch is moved until it reaches the wall surface of the cavity.

According to a second aspect of the present invention, a first plate having a sprue, a runner communicating with the sprue at the time of abutting, and a plurality of end ring-like rings adjacent to the runner. A second cavity including a cavity, a guide hole communicating with the side wall surface adjacent to the outer peripheral wall surface of each cavity with a hole diameter equal to or smaller than the width of the side wall surface, and a submarine gate connecting the runner and the guide hole. A plate and a punch movably fitted and arranged in each guide hole are provided, and after the molten resin is supplied to the plurality of cavities, the plurality of punches are simultaneously pressed until the side walls of the cavity are reached. According to a third aspect of the present invention, the guide hole is formed so as to be located on a side wall surface of an end portion of an end ring-shaped cavity.

Further, a fourth invention of the present invention is characterized in that, in a seal ring formed of a thermoplastic resin in the shape of an end ring, punch marks are formed on the side surface adjacent to the outer peripheral surface.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. In the figure, reference numeral 1 denotes a first plate supported by a supporting plate, for example, and a sprue-2 for supplying the molten resin (P) is formed in the central portion thereof. The plate 1 is of a fixed type. This first plate 1 has a second
Plate 3 of is abutted. In the second plate 3, a runner 4 communicating with the sprue 2 is formed, for example, in a cross shape, and a plurality of end ring-shaped cavities 5 are formed in a portion adjacent to the runner 4. . Particularly, for example, a circular guide hole 6 is formed in a portion of the end portion of each cavity 5 located on the side wall surface so as to communicate with the cavity 5. The guide hole 6 may be formed at a position other than the end. A cylindrical punch 7 is movably fitted and arranged in the guide hole 6. The punch 7 is controlled to move, for example, by a hydraulic cylinder. On the other hand, the runner-4 and the guide hole 6 are submarine gauges.
They are connected by a gate (tunnel gate) 8. still,
The above-mentioned plates are clamped (opened) and opened by a hydraulic cylinder (not shown) or the like.

Molding of the seal ring by this apparatus is performed as follows. As shown in FIGS. 3 and 5, the plates 1 and 3 are clamped by a hydraulic cylinder (not shown) or the like, and the respective patent surfaces are abutted against each other. next,
When the molten resin P is supplied from the sprue-2, the resin P
Is supplied to the guide hole 6 through the runner-4, the submarine gate 8 and the joint portion 8a, and is further supplied to the cavity 5 through the guide hole 6. Incidentally, FIG. 4 is a schematic view showing a filled state of the resin P. Next, as shown in FIG. 6, the punch 7 is moved toward the cavity 5 until the resin P is cured. Along with this, the guide hole 6 and the submarine gauge
The resin P existing in the joint portion 8 a with the joint 8 is cut (or sheared) by the punch 7. On the other hand, the resin P filled in the guide hole 6 is pressed by the punch 7 and press-fitted into the cavity 5. Then, the punch 7 is stopped when it moves to a position where the front end surface of the punch 7 substantially coincides with the side wall surface of the cavity 5. After the resin P is hardened, the second plate 3 is opened by a hydraulic cylinder (not shown) or the like. At this time, for example, sprue-2, runner-4, submarine-geer
The resin of the port 8 is taken out from each plate by using ejector pins (not shown) or the like in a state of being integrated. After that, the ring-shaped resin is taken out from the cavity 5 to obtain the seal ring 9 shown in FIG.
This seal ring 9 is then subjected to heat treatment for fitting the abutments at both ends. At the end portion of the seal ring 9, a pressing trace 7a of the resin P by the punch 7 is formed on the side surface 9b adjacent to the outer peripheral surface 9a.

For the seal ring 9 described above, a resin composition comprising, for example, a heat resistant resin, a reinforcing fiber, a fluorine resin and a filler is used. In particular, examples of the heat-resistant resin include aromatic polyetheretherketone resin (PEK) such as polyetheretherketone resin (PEEK) and polyphenylene sulfide resin (PPS), which have high heat resistance. It has high flame resistance, excellent mechanical properties, excellent electrical properties, and chemical resistance. These materials are used as molding base materials for seal rings.

The heat-resistant resin may be any resin as long as it has heat resistance, but in addition to the above, for example, polycyano aryl ether resin (PEN), aromatic thermoplastic polyimide resin ( TPI) and polyamide 4-6 resin (PA-46) may be used. In addition to high heat resistance, these also have high flame resistance, excellent mechanical properties, excellent electrical properties, and chemical resistance. These materials are used as the molding base material of the oil seal ring of the present invention. If the melting point of these heat-resistant thermoplastic resins is at least 280 ° C. or higher, they can be preferably used in the present invention.

Specifically, the following can be mentioned as examples of combinations in the resin composition used for the seal ring of the present invention.

TPI, PEEK, PEK, PEN,
A resin composition containing 30 to 82% by weight of any one resin selected from the group consisting of PA-46 and PPS, 5 to 45% by weight of carbon fiber, and 2 to 25% by weight of a fluorine-based resin.

PEN, PEEK, PEK, TPI,
30 to 82% by weight of any one resin selected from the group consisting of PPS and PA-46, 5 to 45% by weight of carbon fiber,
A resin composition containing 2 to 25% by weight of a fluorine resin and 10 to 40% by weight of powdered talc as main components.

PEN, PEEK, PEK, TPI,
30 to 78% by weight of any one resin selected from the group consisting of PPS and PA-46, 10 to 45% by weight of carbon fiber, 2 to 25% by weight of fluorine resin, and calcium powder 10
A resin composition whose main component is -40% by weight.

PEN, PEEK, PEK, TPI,
30 to 82% by weight of any one resin selected from the group consisting of PPS and PA-46, 5 to 45% by weight of carbon fiber,
A resin composition containing 2 to 25% by weight of a fluorine resin, 10 to 40% by weight of powdered talc, and 1 to 10% by weight of molybdenum disulfide.

10-40% by weight of the powdered talc
A mixture containing 10 to 40% by weight of a calcium powder filler in place of the above.

A mixture of 5 to 45% by weight of aromatic polyamide fiber instead of 5 to 45% by weight of carbon fiber.

Aromatic polyamide fibers of 5 to 45% by weight are compounded in place of the carbon fibers of 5 to 45% by weight, and calcium powder fillers of 10 to 40% by weight are substituted for powdered talc of 10 to 40% by weight. A resin composition containing

The resin composition of the present invention is used as an additive other than the above-mentioned additives within a range that does not impair the effects of the present invention. Then, solid lubricants, fillers, powder fillers, pigments, and other substances that are stable at a high temperature of about 350 ° C. or higher may be appropriately mixed. For example, in order to further improve the lubricity of the resin composition, a wear resistance improver may be added. Specific examples of this wear resistance improver include carbon, graphite, mica, wollastonite, powders of metal oxides, whiskers such as calcium sulfate, phosphates, carbonates, stearates, and ultra high. A molecular weight polyethylene etc. can be illustrated. The balance of the heat resistant resin when adding such an additive is preferably not less than about 40% by weight.

According to this embodiment, the resin is supplied to the cavity 5 through the guide hole 6 which communicates with the side wall surface of the cavity 5 by using the submarine gate 8. No gate mark is formed on the outer peripheral surface 9a of the ring 9 which is functionally important. Thus, for example, A
Even if it is applied to the hydraulic control system of the automatic transmission of T car,
A sufficient function can be obtained as a ruling.

In addition, the combination of the guide hole 6 and the submarine gate 8 enables molding without forming a gate mark on the outer peripheral surface 9a of the seal ring, so that the second plate 3 can be formed. It is possible to form a plurality of cavities 5.
Therefore, a large number of seal rings 9 can be molded at the same time, and productivity can be improved. Along with this, the cost of the seal ring can be effectively reduced.

In particular, since the guide hole 6 is formed so as to communicate with the side wall surface at one end (or in the vicinity thereof) of one of the cavities 5, the starting point of the molten resin flow at the time of molding. Is the end of the cavity 5. Therefore, the orientation of the resin is good, and the strength and durability are excellent.
It is less likely that damage or cracks will occur when the product is attached to or removed from the application site. The position of the guide hole 6 may be provided at a portion other than the end portion of the cavity 9 depending on the required quality level.

The punch 7 moves toward the side wall surface of the cavity 5 until the resin P supplied to the cavity 5 is cured. At this time, the punch 7 moves.
The resin of the joint portion 8a that connects the guide 8 and the guide hole 6 is automatically cut and separated. Therefore, post-processing such as cutting and separating the seal ring 9 and the gate resin again after the molding work is completely unnecessary, and the work efficiency can be improved and the cost can be effectively reduced.

Furthermore, since the resin P existing in the guide holes 6 is pressed into the cavity 5 by the movement of the punch 7, the resin density in the cavity is increased and the quality of the seal ring can be improved. In addition, the work of removing the resin existing in the guide holes 6 becomes unnecessary, and the further cost reduction effect can be expected.

FIG. 8 shows another embodiment of the present invention. It is a view seen from the opposite direction of FIG. 7, and the position of the gate is set within a range of ± 30 ° from the center of the deployment length of the seal, preferably at a position of about ± 15 °. Figure 2, Figure 4,
As shown in FIGS. 7 and 8, the seal ring piston is moved by moving the gate position from the central portion of the deployment length of the seal (position of 0 °, within a range of about ± 1 to 3 °). It is preferable that stress is not concentrated at the center of the ring when the ring is opened when the ring is assembled into a ring.

The present invention is not limited to the above-mentioned embodiment at all, and for example, a knockout pin communicating with the plate cavity is provided with a vibration device such as mechanical vibration or ultrasonic vibration. It is also possible to enhance the degree of resin filling (filling degree) in the cavity. Further, the number of runners and the number of cavities in the second plate can be appropriately increased or decreased. Further, the seal ring abutment may be formed as a straight cut type or a step cut type, or a chamfered portion may be formed at the corner portion of the abutment portion.

The surface roughness of at least one of the seal ring and the inner surface of the mold is Rmax, Ra, Rz.
Approximately 3 to 25 depending on the evaluation method defined in JIS such as
It is less than or equal to μm, preferably less than or equal to about 8 μm, and more preferably less than or equal to about 3 μm. Because, when the surface roughness exceeds the above-mentioned predetermined range, a lot of scratches are given to the sliding surface,
This is because it is considered to cause wear.

Since it takes a long time to finish the surface of the mating material, it may not be efficient and may be affected by the formation of the transition film of the resin material. It is presumed that the range may be about 3 to 8 μm or less depending on the specifications and conditions.

[0035]

As described above, according to the present invention, the resin is supplied to the cavity through the guide hole communicating with the side wall surface of the cavity by utilizing the submarine gate. No gate mark is formed on the functionally important outer peripheral surface of the seal ring. Therefore, for example, AT
Even if it is applied to a hydraulic control system of an automatic transmission of a vehicle, a sufficient function as a seal ring can be obtained.

In addition, the combination of the guide hole and the submarine gate enables molding without forming a gate mark on the outer peripheral surface of the seal ring, so that a plurality of cavities are formed in the second plate. 5 can be formed. Therefore, a large number of seal rings can be molded at the same time, and productivity can be improved. Along with this, the cost of the seal ring can be effectively reduced.

Particularly, if a guide hole is formed so as to communicate with the side wall surface at one end (or in the vicinity thereof) of one of the cavities, the starting point of the molten resin flow during molding is the end of the cavity. Becomes Therefore, the orientation of the resin is good, and the strength and durability are excellent, and it is difficult for damage and cracks to occur when the resin is attached to or removed from the application site.

Further, the punch 7 moves toward the side wall surface of the cavity before the resin supplied to the cavity is cured. At this time, the punch 7 moves to the joining portion for connecting the submarine gate and the guide hole. The resin is automatically cut and separated. Therefore, post-processing such as cutting and separating the seal ring and the gate resin again after the molding work is completely unnecessary, and not only the work efficiency is improved but also the cost can be effectively reduced.

Further, since the resin existing in the guide holes is pressed into the cavity by the movement of the punch, the resin density in the cavity is increased, and not only the quality of the seal ring can be improved, Since the work of removing the resin existing in the guide holes is not necessary, further cost reduction can be expected.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the second plate shown in FIG.

3 is a cross-sectional view showing a state where resin is injected into the device shown in FIG.

FIG. 4 is a schematic view of a resin injection state.

5 is an enlarged cross-sectional view of a main part of FIG.

FIG. 6 is an enlarged sectional view of an essential part showing a cut state of resin in a gate portion and a press-fitted state of resin in a guide hole portion by moving a punch.

FIG. 7 is a plan view of the seal ring.

FIG. 8 is a plan view of a main part showing another embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a conventional example.

FIG. 10 is a schematic view of a resin injection state according to FIG. 9.

FIG. 11 is a schematic view of an example in which a gate is provided on the outer peripheral surface.

[Explanation of symbols]

 1 1st plate 2 sprue 3 2nd plate 4 runner 5 cavity 6 guide hole 7 punch 8 submarine gate 8a joining part 9 seal ring 9a outer peripheral surface 9b side surface 7a punch mark P resin

Claims (4)

[Claims] 1. A first plate having a sprue, a runner communicating with the sprue at the time of abutting, an end ring-shaped cavity adjacent to the runner, and a side wall surface adjacent to an outer peripheral wall surface of the cavity. And a second plate including a submarine gate that connects the runner and the guide hole, and a punch that is movably fitted and arranged in the guide hole, and is in a molten state in the cavity. An injection molding apparatus, characterized in that the punch is moved until it reaches the wall surface of the cavity after the resin is supplied. 2. A first plate having a sprue, a runner communicating with the sprue at the time of abutting, a plurality of end ring-shaped cavities adjacent to the runner, and outer peripheral wall surfaces of the respective cavities. A guide hole communicating with the adjacent side wall surface with a hole diameter equal to or smaller than the width of the side wall surface, a second plate including a submarine gate connecting the runner and the guide hole, and each guide hole. Injection molding, characterized in that it comprises a punch that is movably fitted and arranged in the cavity, and that after the molten resin is supplied to the plurality of cavities, the plurality of punches are simultaneously moved until they reach the side wall surface of the cavity. apparatus. 3. The injection molding apparatus according to claim 1, wherein the guide hole is formed so as to be located on a side wall surface of an end portion of an end ring-shaped cavity. 4. A seal ring formed of a thermoplastic resin in the shape of an end ring, wherein punch marks are formed on a side surface adjacent to the outer peripheral surface.