JP4727341B2 - Seal ring molding method and molding die - Google Patents

Description

  The present invention relates to a molding method and a molding die for a seal ring such as an oil seal ring that prevents leakage of hydraulic oil filled in an automatic transmission of an automobile.

As an oil seal ring (hereinafter simply referred to as a seal ring) incorporated in an automatic transmission, the one shown in FIG. 11 is conventionally known. The seal ring A ₁ is a cross-sectional shape to the inner periphery of the annular portion a which is rectangular, its annulus a more provided a small annular projection b of the axial width ring-shaped.

The seal ring A _1, since the outer peripheral surface and both side surfaces of the annular portion a is a sealing surface c, the outer peripheral surface and excellent surface accuracy on both sides is required. Moreover, the sealing surface c for sealing between the contact surface by the surface contact of the rotary member such as a rotary shaft, the seal ring A ₁ is also required heat resistance and wear resistance.

When the seal ring A ₁ as described above is molded from cast iron, polishing of the entire outer periphery is required after molding. Therefore, in recent years, a synthetic resin having heat resistance that can be injection-molded, for example, polyetheretherketone (PEEK) Injection molding is performed using

As a mold for injection molding of the seal ring A1, the _one described in Patent Document 1 is conventionally known. In this injection mold, as shown in FIG. 12, a molten resin is press-fitted into a cavity 23 formed by a fixed-side mold plate 21 and a movable-side mold plate 22 that is clamped, and a seal ring A _{1 is used.} After the mold is opened, the movable side mold plate 22 is opened, and the core pin 24 supported by the movable side mold plate 22 moves forward, so that the step portion 25 provided on the outer periphery of the tip end of the core pin 24 becomes the seal ring A1. As shown in FIG. 13, the seal ring A <b> ₁ is protruded from the movable side mold plate 22 by the action of pressing one side surface of the annular protrusion b.

Also, movement from the small-diameter portion 24a of the core pin 24 to remove the seal ring A _1, provided movably runner ejector pins 27 into the pin hole 26 formed in the core pin 24, the axial direction of the runner ejector pins 27 as shown in FIG. 14 by projecting the runners d, by relative axial movement of the seal ring a engaging member 28 is engaged on one side of _one and the core pin 24, as shown in FIG. 15, the core pin derived is a seal ring _{a 1} from the small-diameter portion 24a of 24.
JP 2004-9306 A

Incidentally, in the injection mold described in Patent Document 1, the gate g is torn when the runner ejector pins 27 eject the runners d, as shown in FIG. 14, Getobari e the seal ring A ₁ There are formed, moreover, since the seal ring a ₁ is the outer peripheral surface and both side surfaces are removed in a non-constrained state from the small-diameter portion 24a, the Getobari e is taken out direction opposite to the seal ring a _1, as shown in FIG. 15 will be left in the seal ring a ₁ lying on direction, there is a disadvantage that must be removed Getobari e by post-processing.

An object of the present invention is to provide a molding method and a mold for molding capable of molding a seal ring having no gate burr and excellent in sealing performance.

In order to solve the above problems, in the sealing ring molding method according to the present invention, the movable side mold plate is clamped with respect to the fixed side mold plate, and the molten resin is put into the cavity formed between the mold plates. A seal ring having a cylindrical outer periphery and inner periphery is formed by press-fitting. After the molding, the movable side mold plate is opened, and one side surface of the seal ring remaining on the movable side mold plate is pressed to form the seal ring. In the molding method of the seal ring so as to be taken out, a gate block for molding a part of the inner peripheral surface of the seal ring is provided on the fixed side mold plate so as to be movable with respect to the movable side mold plate and the fixed side mold plate . A sprue communicating with the first runner formed on the movable side template on the gate block, one end communicating with the first runner, the other end opening on the outer peripheral surface of the gate block, and the other end opening being injected For gate Are inclined second provided a runner separately of, and allowed a seal ring flowing molten resin into the cavity from the injection gate sprue is pressed to flow to the first runner and a second runner of the gate block After molding the seal ring and before opening the movable side mold plate, the gate block is moved in the fixed side mold plate in a direction away from the movable side mold plate, and the gate of the seal ring is moved to the injection gate. This is a configuration in which shearing is performed at the edges .

  Here, the seal ring may be provided with an annular protrusion having an axial width smaller than the annular portion on the inner periphery of the annular portion having a rectangular cross section, or a ring shape having a substantially rectangular cross section. There may be.

In the mold for molding a seal ring according to the present invention, an annular portion having an axial width smaller than that of the annular portion on the inner periphery of the annular portion between the fixed side die plate and the fixed side die plate in a clamped state. A movable side mold plate that forms a cavity for molding a seal ring formed with a protruding portion, and a slidably inserted into a pin insertion hole formed in the movable side mold plate, toward the fixed side mold plate In a mold for sealing ring comprising a core pin that presses one side surface of an annular projecting portion of a seal ring formed during movement and protrudes the seal ring from a movable side mold plate, the fixed side plate has a fixed side A block block is provided with a block fitting hole that opens on the end surface and outer peripheral surface of the core part that molds the inner peripheral surface of the seal ring of the template, and a gate block that molds a part of the inner peripheral surface of the seal ring in the block fitting hole. Mates slidably A sprue communicating with the first runner formed in the movable mold plate to the gate block, communicating with one end to said first runner and the other end open at the outer peripheral surface of the gate block, the other end opening of An inclined second runner that is an injection gate is provided separately, and after the molding of the seal ring that injects molten resin from the gate into the cavity, the gate block is moved to the movable side before the movable side mold plate is opened. A configuration was adopted in which the seal ring gate was sheared at the edge of the injection gate by moving in the fixed side mold plate in a direction away from the template plate .

  In the molding die for a seal ring having the above-described configuration, a pin formed on the movable side mold plate is provided with a tapered surface having a large diameter end on the outer periphery of the tip portion facing the fixed side mold plate of the core pin. If a taper surface that fits the taper surface is provided on the inner periphery of the opening end of the insertion hole on the fixed side mold plate side, the core pin taper surface and the pin insertion when the core pin moves away from the fixed side mold plate The taper surface of the hole is surface-engaged to hold the core pin on the axial center of the pin insertion hole, and no gap is formed between the sliding surfaces of the core pin and the pin insertion hole. A seal ring with high dimensional accuracy can be obtained.

In the mold for molding a seal ring according to the present invention, a movable mold for forming a seal ring having a substantially rectangular cross section is formed between the fixed side mold plate and the fixed side mold plate in a clamped state. A side mold plate, and an ejector pin that is slidably supported by the movable mold plate and presses one side of the seal ring that is formed when moving toward the fixed mold plate and projects the seal ring from the movable mold plate In a mold for molding a seal ring comprising:
The fixed-side mold plate is provided with a block fitting hole that opens on the end surface and the outer circumferential surface of the core portion that molds the inner circumferential surface of the seal ring of the fixed-side mold plate, and the seal ring has an inner surface within the block fitting hole. A gate block that forms a part of the peripheral surface is slidably fitted, a sprue that communicates with the first runner formed on the movable side mold plate, and one end that communicates with the first runner. Forming a seal ring in which an end is opened on the outer peripheral surface of the gate block and an inclined second runner having an opening at the other end as an injection gate is separately provided, and molten resin is injected into the cavity from the gate after, and so as to shear the gate of the gate block is moved in the direction away from the movable side mold plate in fixed die plate within the sealing ring before the mold is opened the movable side mold plate at the edge of the injection gate structure It was adopted.

  As described above, after the seal ring is formed, the gate block is moved in the axial direction in a state in which each surface of the outer periphery of the seal ring is constrained by the fixed-side mold plate and the movable-side die plate. The gate on the seal ring side is sheared along the inner peripheral surface of the seal ring by the injection gate. For this reason, it is possible to obtain a seal ring with no gate burr and excellent sealing performance.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6 show a first embodiment of a seal ring molding die according to the present invention. As shown in FIG. 1, the molding die for the seal ring A ₁ includes a fixed-side mold plate 1 and a movable-side mold plate 2, and the fixed-side mold plate 1 faces the movable-side mold plate 2. core portion 3 for forming the inner periphery of the seal ring a ₁ shown in FIG. 11 is formed on. Further, as shown in FIGS. 1 and 2, the fixed-side template 1 is formed with a block fitting hole 4 that opens on the end surface and the outer peripheral surface of the core portion 3 facing the movable-side template 2, and the block fitting is performed. gate block 5 for molding the inner circumferential surface portion of the seal ring a ₁ in Goana 4 is fitted slidably. The gate block 5 is movable with respect to the movable side template 2.

Movable side mold plate 2 is composed of a circumferential surface mold plate 2a for molding the outer peripheral surface of the seal ring A _1, the side mold plate 2b for forming one side of the oil seal ring A _1, both templates 2a, 2b is combined and integrated.

  A pin insertion hole 6 is formed in the side surface mold 2b of the movable side mold 2 so as to face the core portion 3, and a core pin 7 is slidably inserted into the pin insertion hole 6.

Core pin 7, so as to mold one side of the inner peripheral end portion and an annular projection b of the annular portion a at the outer peripheral portion of the outer and the distal end surface of the fixed die plate 1 opposed to the distal end portion of the seal ring A ₁ ing. The outer periphery of the distal end portion of the core pin 7 is a tapered surface 8 having a large diameter end on the distal end side of the core pin, while the inner periphery of the distal end portion of the pin insertion hole 6 is formed with a tapered surface 9 that matches the tapered surface 8.

  A pin hole 10 extending in the axial direction of the core pin 7 is formed in the core pin 7 at a position facing the gate block 5, and a runner protruding pin 11 is inserted into the pin hole 10.

  The runner protruding pin 11 is slidable in the axial direction, and the first runner 12 is formed on the front side of the runner protruding pin 11 in a retreat stop state in which the runner protruding pin 11 is separated from the gate block 5.

  Now, the gate block 5 is movable in a state in which the end surface facing the core pin 7 is held in a forward stop position where the end surface is flush with the end surface of the core portion 3, and the core pin 7 is held in a backward stop position separated from the core portion 3. When the side mold plate 2 is clamped, a seal ring forming cavity 13 is formed between the movable mold plate 2 and the fixed mold plate 1.

  The gate block 5 includes a sprue 14 that communicates with the first runner 12 in a clamped state of the movable side mold plate 2, a second runner 15 that communicates with the first runner 12, and an inner periphery of the cavity 13. An injection gate 16 is formed in communication with the injection gate 16.

The molding die for the seal ring shown in the embodiment has the above-described structure. As shown in FIG. 1, when the molten resin is press-fitted into the sprue 14 with the movable side mold plate 2 being clamped, the molten resin is flows to the first runner 12 and second runner 15 flows from the injection gate 16 into the cavity 13, the seal ring a ₁ is molded.

After the molding of the seal ring A ₁ , when the gate block 5 is retracted in the direction away from the core pin 7, the gate g on the seal ring A ₁ side is sheared by the edge 16 a of the injection gate 16 formed on the gate block 5. The

At this time, the seal ring A ₁ has an outer peripheral surface constrained by the fixed-side mold plate 1 and the movable-side mold plate 2, so that the gate g has no escape, and the annular protrusion is formed by the edge 16 a of the injection gate 16. It will shear accurately along the inner peripheral surface of b. For this reason, a gate burr | flash does not generate | occur | produce.

  FIG. 3 shows a state in which the gate block 5 is retracted, and B shows a shear plane of the gate g.

After retraction of the gate block 5, the mold is opened the movable mold plate 2, seal ring A ₁ which is molded as shown in FIG. 4, is a state of remaining in the movable mold plate 2. After the mold opening, when the runner protruding pin 11 is advanced toward the fixed side mold plate 1, the runner d is projected as shown in FIG. At this time, since the gate g is already sheared, the runner d falls and is appropriately discharged.

After projecting runners d, is advanced toward the core pin 7 on the fixed side mold plate 1, the outer peripheral portion of the distal end surface presses the one side surface of the annular projection b of the seal ring A _1, by the pressing, Fig. 6 as shown in, the seal ring a ₁ after the molding is protruded from the movable side mold plate 2.

Protrusion of the seal ring A _1, as described above, since due to the pressing of one side of the annular projection b, without marks protrude on one side of the sealing surface c of the annular portion a is formed, it is possible to obtain a good seal ring a ₁ of the sealing property.

Further, after molding of the seal ring A _1, and since the outer peripheral surfaces of the seal ring A ₁ is to shear the gate g and move the gate block 5 in a state to be bound, the post processing without Getobari required cheap seal ring a ₁ of cost can be obtained.

7 to 9 show a second embodiment of a seal ring molding die according to the present invention. This embodiment shows a mold for molding the seal ring A ₂ of square cross section, the cavity 13 formed by the fixed die plate 1 and the movable side mold plate 2 and the shape corresponding to the seal ring A ₂ Has been.

  Further, a pin hole 17 reaching one side surface of the cavity 13 is formed in the side surface forming mold plate 2 b of the movable side mold plate 2, and an ejector pin 18 is slidably inserted into the pin hole 17.

  Since the other configuration is the same as the seal ring molding die shown in the first embodiment, the same parts are denoted by the same reference numerals and description thereof is omitted.

Also in the seal ring molding die shown in the second embodiment, after the seal ring A ₂ shown in FIG. 7 is molded, the gate block 5 is moved backward in the direction away from the side molding template 2b, so that the injection is performed. since the gate g of the seal ring a ₂ is sheared by the edge 16a of use gate 16, as shown in FIG. 8, it can be obtained without Getobari seal ring a _2.

In molded taken out of the seal ring A ₂ after retraction of the gate block 5, and mold opening the movable side mold plate 2, is moved towards the ejector pin 18 to the fixed die plate 1, as shown in FIG. 9 to, to protrude the seal ring a _2. At this time, the runner protruding pin 11 is also moved toward the fixed side template 1 so as to protrude the runner d in advance.

In mold of the seal ring shown in the second embodiment, by changing the shape of the cavity 13, shown in cross-section a rectangular seal ring A ₃ and FIG. 10 (II), as shown in FIG. 10 (I) it is possible to form the trapezoidal cross section of the seal ring a _4, such as seal rings, such as.

Sectional drawing which shows 1st Embodiment of the metal mold | die for the seal ring which concerns on this invention Right side view of FIG. Sectional view with the gate block retracted Sectional view showing mold open state of movable side template Sectional view showing the runner's protruding state Sectional view showing the protruding state of the seal ring Sectional drawing which shows 2nd Embodiment of the metal mold | die for the seal ring which concerns on this invention Sectional view with the gate block retracted Sectional view showing the protruding state of the seal ring (I), (II) are sectional views showing other examples of seal rings A perspective view showing a part of a conventionally known seal ring Sectional view showing a conventional molding die Sectional view showing a mold open state of the mold shown in FIG. 12 Sectional view showing the runner's protruding state Sectional view showing the oil seal ring removed

A _{1 to} A ₄ Seal ring a Annular part b Annular protrusion g Gate 1 Fixed side mold plate 2 Movable side mold plate 3 Core part 4 Block fitting hole 5 Gate block 7 Core pin 8 Tapered surface 9 Tapered surface 13 Cavity 14 Sprue 15 Second runner 16 Injection gate 18 Ejector pin

Claims (6)

The movable side mold plate is clamped with respect to the fixed side mold plate, and a molten resin is press-fitted into a cavity formed between the mold plates to form a seal ring whose outer periphery and inner periphery are cylindrical, After molding, in the molding method of the seal ring, the movable side mold plate is opened and the seal ring is removed by pressing one side surface of the seal ring remaining on the movable side mold plate.
A gate block for forming a part of the inner peripheral surface of the seal ring on the fixed side mold plate is provided to be movable with respect to the movable side mold plate and the fixed side mold plate , and the gate block is formed on the movable side mold plate. A sprue communicating with the first runner, an inclined second runner having one end communicating with the first runner, the other end opened at the outer peripheral surface of the gate block, and the other end opened as an injection gate ; the separately provided, by flow molding the sealing ring a molten resin flowing pressed into the sprue of the gate blocks the first runner and second runners into the cavity from the injection gate, forming the sealing ring after, in the mold opening injection gate of the edge gates of the gate block is moved in the direction away from the movable side mold plate in fixed die plate within the sealing ring in front of the movable side mold plate Molding process of the seal ring, characterized in that so as to cross.   The method for forming a seal ring according to claim 1, wherein the seal ring includes an annular portion having a rectangular cross section and an annular protrusion formed on an inner periphery of the annular portion and having a smaller axial width than the annular portion.   The method for forming a seal ring according to claim 1, wherein the seal ring has a ring shape with a substantially rectangular cross section. A cavity for molding a seal ring in which an annular protrusion having a smaller axial width than the annular portion is formed on the inner periphery of the annular portion between the fixed-side template and the fixed-side template in a clamped state. One side surface of an annular protrusion of a seal ring that is slidably inserted into a pin insertion hole formed in the movable side mold plate and formed toward the fixed side mold plate. In a mold for molding a seal ring comprising a core pin that presses and projects a seal ring from a movable mold plate,
The fixed-side mold plate is provided with a block fitting hole that opens on the end surface and the outer circumferential surface of the core portion that molds the inner peripheral surface of the seal ring of the fixed-side mold plate, A gate block that forms a part of the peripheral surface is slidably fitted, a sprue that communicates with the first runner formed on the movable side mold plate, and one end that communicates with the first runner. Forming a seal ring in which an end is opened on the outer peripheral surface of the gate block and an inclined second runner having an opening at the other end as an injection gate is separately provided, and molten resin is injected into the cavity from the gate after, and so as to shear the gate of the gate block is moved in the direction away from the movable side mold plate in fixed die plate within the sealing ring before the mold is opened the movable side mold plate at the edge of the injection gate this Mold of the seal ring according to claim.   A taper surface having a large diameter end is provided on the outer periphery of the tip portion of the core pin facing the fixed side mold plate, and the pin insertion hole formed in the movable side mold plate has an opening end on the fixed side mold plate side. The mold for molding a seal ring according to claim 4, wherein a taper surface adapted to the taper surface is provided on a circumference. A movable side mold plate that forms a cavity for molding a seal ring having a substantially rectangular cross section between the fixed side mold plate and the fixed side mold plate in a clamped state, and is slidably supported by the movable side mold plate. In a mold for molding a seal ring comprising an ejector pin that presses one side surface of a seal ring that is molded during movement toward the fixed side mold plate and projects the seal ring from the movable side mold plate.
The fixed-side mold plate is provided with a block fitting hole that opens on the end surface and the outer circumferential surface of the core portion that molds the inner circumferential surface of the seal ring of the fixed-side mold plate, and the seal ring has an inner surface within the block fitting hole. A gate block that forms a part of the peripheral surface is slidably fitted, a sprue that communicates with the first runner formed on the movable side mold plate, and one end that communicates with the first runner. Forming a seal ring in which an end is opened on the outer peripheral surface of the gate block and an inclined second runner having an opening at the other end as an injection gate is separately provided, and molten resin is injected into the cavity from the gate after, and so as to shear the gate of the gate block is moved in the direction away from the movable side mold plate in fixed die plate within the sealing ring before the mold is opened the movable side mold plate at the edge of the injection gate this Mold of the seal ring according to claim.

Images