JPH047984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold used for injection molding of synthetic resin.

(Prior art) In this type of mold, as shown in Fig. 7,
A plurality of nested molds 16 are joined from the U-shaped open portion and inserted into the mold base 14, which has an insertion portion 12 with a substantially U-shaped front face erected on the mold mounting plate 10. Then, using the U-shaped back wall and the inner and lower walls as reference planes,
The nested mold group is pressed and fixed by a holding member 20 pressed from the left by a horizontal clamp cylinder 18, and is pressed from above by a vertical clamp 24 which is vertically operated by a vertical clamp cylinder 22.
The position is fixed.

In this mold, a plurality of nested molds 16 are inserted into a common U-shaped space of the insertion part 12, so that
The advantage is that the entire molding die can be made smaller, and the means for pressing and fixing each nested mold 16 can be handled by a common horizontal clamp cylinder 18 and vertical clamp cylinder 22, which simplifies the overall configuration of the molding die. There is.

(Problems to be Solved by the Invention) However, it has been found that the conventional molding die described above also has the following problems.

That is, the outer dimensions of each nested mold 16 are within the allowable tolerance, but there are some variations.

For this reason, as shown in FIG. 7, the corners of the nested molds 16a and 16c with large external dimensions may collide with each other, resulting in galling and deformation of the corners, and nested molds 16b and 16d with small external dimensions may It is not pressed effectively by the holding member 20 or the vertical clamp 24, causing backlash, making it difficult to maintain accuracy during long-term use, and the life of the nesting die 16 and the like is short.

Therefore, the present invention was made to solve the above problems, and its purpose is to solve the problem even if the outer dimensions of the nested mold vary within the allowable tolerance.
To provide a molding die which can uniformly press and fix each nesting mold without wobbling, can easily maintain precision, and can extend the life of the nesting mold, etc.

(Means for solving the problems) The above object can be achieved by the present invention having the following configuration.

That is, in the present invention, within a set of mold bases,
Each of the multiple sets of nested molds inserted from the direction perpendicular to the mold opening/closing direction of the mold is inserted with the wall surface touching the adjacent nested mold, and the nested molds are inserted against the reference plane in the mold base. In a molding die in which a mold is pressed and fixed from the side, each of the nested molds is a nested mold having a substantially rectangular planar shape, and each corner of the nested mold has a maximum input of external dimensions. A chamfer is applied which is equal to or larger than the dimensional difference between the child mold and the nested mold with the smallest external dimension, and from at least one side of the space of the mold base, each of the nested molds facing that one side is chamfered separately. It is characterized in that a pressing means for pressing is provided.

(Function) The nested molds 38 and 43 inserted into the mold bases (movable mold base 42, fixed mold base 37) have a corner portion with a diameter of the largest nested mold and the smallest nested mold. Because the chamfering is applied to exceed the size difference, even if there are variations in the outer diameter of the nested molds, the corners will not interfere with each other during joining, and the predetermined wall surfaces will be brought into contact with each other. In addition, since each part is pressed separately by the pressing means, it is positioned and fixed without wobbling.

Therefore, even if there are variations in the external dimensions of each nesting mold, the nesting molds will be fixed without the corners being twisted or deformed, with the predetermined wall surfaces in contact with each other, and without wobbling. It is.

Furthermore, in the present invention, multiple sets of nested molds can be inserted into the mold base from a direction perpendicular to the mold opening/closing direction of the mold, so that the nesting work can be easily performed. .

Furthermore, within the mold base, each nested mold is inserted with the wall surface in contact with the adjacent nested mold, so
It is also possible to simplify the mold structure.

(Example) Hereinafter, preferred embodiments embodying the present invention will be described in detail based on the accompanying drawings.

First, the overall outline of the molding die will be explained.

In FIG. 1, 30 is a fixed type, 31 is an intermediate type, and 32 is a movable type. Fixed type 30 is fixed platen 3
3, and a runner stripper plate 36 connected to the fixed base 34 by a limiting bolt 35 so as to be movable toward and away from the fixed base 34 over a predetermined stroke.

The intermediate mold 31 is constructed by fitting and fixing four nesting molds 38 into a U-shaped space of an intermediate mold base 37 whose front shape is approximately U-shaped by a fixing mechanism to be described later. 39, it is connected to the runner stripper plate 36 so that it can move in and out of the runner stripper plate 36 by a predetermined stroke. Further, the intermediate mold 31 is urged in a direction away from the runner stripper plate 36 by a spring 40.

The movable mold 32 includes a movable platen 41 that is moved toward and away from the intermediate mold 31 and the fixed mold 30 by an appropriate hydraulic cylinder (not shown), a movable mold base 42 fixed to the movable platen 41, and a movable mold base 42 that is fixed to the movable platen 41. A movable nesting mold 43 is provided to be fixed to the U-shaped portion of the movable mold base 42 by a fixing mechanism to be described later. Note that this movable mold 32 is also connected to the intermediate mold 31 by a limiting pin 44 so as to move toward and away from the intermediate mold 31 by a predetermined stroke.

A molding cavity 45 is defined by the nesting mold 38 of the intermediate mold 31 and the movable nesting mold 43 opposing thereto. In the illustrated example, the pair of nesting molds 38' and movable nesting molds 43' are shown as substitute nesting molds that do not form any cavities.

Reference numeral 46 denotes a protruding pin for ejecting the molded product, which is inserted through the movable nesting die 43, and is protruded by a protruding rod 48 driven against the biasing force of a spring 47.

Next, 49 is a hot runner block,
It is disposed within the above-mentioned fixed mold 30 with a heat insulating material 50 interposed therebetween. One end of this hot runner block 49 faces a nozzle entry hole 51 provided in the stationary platen 33 and is touched by a nozzle 52. The other end of the hot runner block 49 is branched, and each branched end projects from the fixed mold base 34 toward the corresponding nested mold 38 of the intermediate mold 31.

A sprue bush 53 is formed in a cap shape to cover each branch end of the hot runner block 49, and is fixed to the fixed base 34 by a fixing plate 54 at its base end. An undercut portion 55 for locking the runner branch is provided around the outer periphery of the tip of the sprue bush. Also, at the tip of the sprue bush 53, there is a hot runner block 4.
A resin path 57 is opened from the resin path 9 to the hot runner 56 . The sprue bushing 53 is fitted into the through hole 58 provided in the runner stripper plate 36, and when the mold is closed as shown in FIG. It is set to protrude from the surface of the par plate 36.

On the other hand, a recess 59 on the outer surface of the nesting mold 38 of the intermediate mold 31 has a depth and width that can sufficiently cover the tip of the sprue bush 53 that protrudes from the surface of the runner stripper plate 36 when the mold is closed. is formed. A runner 60 is formed that communicates the recess 59 and the cavity 45 via a gate. In this case, the gate position can be varied within the range of the width of the recess 59, which has a relatively wide area, so when replacing the nesting mold 38 according to various molded products, there is freedom in designing the gate position. The degree becomes large. A recess 59' similar to the recess 59 described above is also formed on the back surface of the substitute nesting mold 38'. As shown in the figure, a dummy runner branch is formed by this recess 59' each time the molding is performed.

Next, the nested structure and its fixing mechanism will be explained in more detail with reference to FIG. Note that the movable mold 32 and the intermediate mold 31 have the same nested molds and their fixing mechanisms, so only the movable mold will be described.

FIG. 3 is a view of the movable mold 32 seen from the parting surface.

The four movable nesting molds 43 have a rectangular front shape and chamfered corners, and are built into the U-shaped space of the movable mold base 42 in two rows with their side walls touching each other. There is.

The size of the chamfer at the corner of each movable nesting mold 43 is as follows:
As shown in the figure, three movable nesting molds 43a, 43
b, 43c are in contact with the back wall and inner and lower surface of the U-shaped space, which are the reference planes, even if there is a dimensional difference between the movable nesting molds 43, the seventh
As shown in the figure, the corner of the nested mold should be large enough so that it does not interfere, that is, the size should be larger than the dimensional difference between the largest nested mold and the smallest nested mold.

The need to make the dimensional difference greater than the above is necessary for nested types a, b, and c, as schematically shown in Figure 4.
In order to prevent the corners of nested molds a and c from blocking, the sizes of the chamfers to be applied to nested molds a and c should be "a~b" and "b".
〜c'' or more.

By chamfering the corners of each of the movable nesting molds 43 as described above, the side wall surfaces of the movable nesting molds 43 can surely come into contact with each other.

The movable nesting mold 43 is provided with a groove 61 at the center of its upper surface and a convex portion 62 at the center of its lower surface perpendicular to the mold opening direction (Fig. 1). The mold 43 has its grooves 61 and protrusions 62.
A convex portion provided on the lower surface of the vertical clamp of the vertical clamp cylinder, which will be described later, fits into the concave groove 61 on the upper surface of the movable nesting mold 43 in the upper row, and a convex portion provided on the lower surface of the vertical clamp of the vertical clamp cylinder, which will be described later, fits into the lower surface of the movable nesting mold 43 in the lower row. The protrusion 62 provided is the movable base 4
It fits into a groove 63 provided on the lower surface of the U-shaped space No. 2.

By engaging the movable nesting molds 43 in this manner, the movable nesting molds 43 are prevented from shifting in the mold opening/closing direction.

Incidentally, the wall surfaces of the movable nesting molds 43 in the vertical row, the inner wall of the U-shaped space, and the inner wall of the presser member pressed by the horizontal clamp cylinder described later may also be engaged with the concave and convex portions.

Furthermore, the fixation by the uneven engagement is not limited to the engagement by the relationship between the groove and the protrusion, but also by the circular recess and the cylindrical protrusion that fits therein, or by straddling the opposing wall surfaces of the movable nesting molds 43. Alternatively, the key may be fixed by being fitted into a key groove provided therein (not shown).

A pair of horizontal clamp cylinders 64 are provided at both ends of the U-shaped portion of the movable base 42, and their rods protrude into the U-shaped space. A horizontal clamp 65 is fixed to the above-mentioned rod end, and the side wall surface of the U-shaped space of this horizontal clamp 65 is formed into a tapered surface. The tapered surface of the horizontal clamp 65 connects the two upper and lower movable nesting molds 43c on the U-shaped open side of the four movable nesting molds 43,
43d Abuts against tapered surfaces formed at both outer ends of the presser member 66 that abuts against the wall surface.

When the horizontal clamp cylinder 64 is driven, the horizontal clamp 65 pushes the holding member 66 through its tapered surface, thereby pressing and fixing the movable insert die 43.

67a and 67b are leaf springs, and the holding member 66
T-grooves 68a, 68b are opened at positions corresponding to the inner wall surfaces of the upper and lower movable nesting molds 43c, 43d.
The movable nesting molds 43c and 43d are respectively fitted into the movable nesting molds 43c and 43d so as to be able to protrude while being prevented from coming off. As a result, even if the movable nesting die 43 has variations in external dimensions, the movable nesting die 43 is reliably pressed and its lateral wobbling is eliminated.

Reference numeral 69 denotes a vertical clamp cylinder, which is disposed above the U-shaped portion of the movable mold base 42 and clamps the movable insert mold 43 by a vertical clamp 70 fixed to the lower end of the rod.
Press. Further, plate springs 71a and 71b similar to those described above are provided on the lower surface of the vertical clamp 70.
The upper surfaces of the two movable nesting molds 43a and 43d in the upper row are pressed respectively. As a result, even if the movable nesting mold 43 has variations in outer diameter, the movable nesting mold 43 can be reliably pressed and the movable nesting mold 43 can be prevented from wobbling in the vertical direction.

The present invention is configured as described above. Therefore, in order to incorporate the movable nesting mold 43 into the U-shaped space of the movable mold base 42, first, the four movable nesting molds 43a, 43b, 43c, and 43d are inserted between the movable mold base 42 and the wall surface. The wall surface contact portions of the movable nesting molds 43 are engaged with each other, and the holding member 66 is attached to the U-shaped open portion.

In this case, since the corners of each of the movable nesting molds 43 are chamfered as described above, the corners of the movable nesting molds 43 are in reliable contact with the wall surfaces without being blocked.

Next, when the horizontal clamp cylinders 64, 64 and the vertical clamp cylinder 69 are driven, the movable nesting die 43 is tightened to the upper right in FIG. Tightened downward. At the same time, the movable nesting die 43 is pressed to the right by the leaf springs 68a, 68b and downward by the leaf springs 71a, 71b, so that the movable nesting die 43 has variations in outer diameter. Even if the space is not fixed, the back wall and inner and lower surfaces of the U-shaped space are used as reference planes to ensure positioning and fixation.

In this way, the corners of the movable nesting mold 43 are chamfered, and the leaf springs 68a, 68b, 71a, 7
1b, the movable nesting molds 43 are securely brought into contact with each other with predetermined wall surfaces, and are positioned and fixed without wobbling.

The fixed nesting mold 38 can also be fixed in the same manner.

In this embodiment, the vertical clamp cylinder 69 (therefore, the vertical clamp 70 and the leaf spring 71
a, 71b) do not necessarily need to be provided. In addition, in the above, the leaf springs 68a, 68b, 71
a and 71b are used, but other elastic bodies such as rubber and springs may be used, or a hydraulic actuator may be used.

Further, the number of nested types is not limited to four, but may be a plurality.

FIG. 5 shows another embodiment.

In this embodiment, coil springs 72a and 72b are installed inside the respective holes 73a and 73b of the holding member 66 as pressing means for pressing the nesting mold 43,
The nesting mold 43 is inserted through pressers 74a and 74b provided in the holes 73a and 73b so that their tips can freely protrude to the outside.
I'm trying to press it.

A similar coil spring 7 is also used for the vertical clamp 70.
5a, 75b and pressers 76a, 76b are provided inside to press the nested die 43.

It is clear that this embodiment also provides the same effects as described above.

FIG. 6 shows yet another embodiment.

In this embodiment, instead of the presser member 66, a support member 77 is removably inserted into grooves provided on the upper and lower surfaces of the open portion of the U-shaped space.
Coil springs 79a, 7 are installed in cylinder holes 78a, 78b opened in the inner wall surface of this support member 77.
Pistons 80a, 80b biased by 9b
The rod ends of the pistons 80a and 80b press the corresponding nesting molds 43.

When the nesting die 43 is replaced, fluid is fed into the right chambers of the cylinder holes 78a, 78b through the flow path 81 to retract the pistons 80a, 80b.

Similarly, coil springs 82a, 82b and pistons 83a, 83b are provided on the inner upper surface of the U-shaped space.
is provided inside to press the nesting die 43 downward. 84 is a flow path for piston retraction.

In this way, this embodiment does not have the above-mentioned vertical clamp cylinder 64 and horizontal clamp cylinder 69, but each piston 80a, 80b, 83a, 8
3b presses the nested molds 43 separately, so that the same effect as described above is obtained.

In addition, in the above, the coil spring may be set to act for retracting the piston, and the nested die may be pressed and fixed via the piston using fluid pressure.

Next, the forming operation will be outlined.

After the mold is clamped, molten resin is injected into the cavity 45 from the nozzle 52 through the hot runner 56, the resin path 57, the recess 59, and the runner 60 to perform molding.

The movable type 3 is moved by driving a hydraulic cylinder (not shown).
2, the intermediate mold 31 is biased by the spring 40, so that the space between the intermediate mold 31 and the runner stripper plate 36 is first opened. Since the runner branch is held by the undercut portion 55 of the sprue bush 53, it is cut from the molded product at the gate portion and remains on the runner stripper plate 36 side.

Similarly, the runner branch corresponding to the substitute nested mold 38' remains on the runner stripper plate 36 side as a dummy runner branch.

If the movable mold 32 is further opened, the intermediate mold 31 is restricted by the restriction pin 39, so the intermediate mold 31
and the movable mold 32 are opened, and the molded product is
It sticks to. This molded product is ejected by protruding the ejecting pin 46, and is dropped and collected. The runner branch and the dummy runner branch are regulated by the restriction pin 44, the restriction pin 39, and the restriction bolt 35, are pushed by the runner stripper plate 36, and are dropped and collected from the tip of the sprue bush 53.

(Effects of the Invention) The corners of the nested mold inserted into the mold base are chamfered to a size greater than the difference in outside diameter between the largest and smallest nested molds. Even if there are variations in the outer diameter of the nested molds, the corners will not interfere with each other during joining, and the predetermined wall surfaces will be brought into contact with each other, and each part will be pressed separately by the pressing means. Positioned and fixed without wobbling.

Therefore, even if there are variations in the external dimensions of each nesting mold, the nesting molds will be fixed without the corners being twisted or deformed, with the predetermined wall surfaces in contact with each other, and without wobbling. Therefore, it is easy to maintain accuracy, has a long life, and can be used stably for a long period of time.

In addition, multiple sets of nested molds can be inserted into the mold base from a direction perpendicular to the mold opening/closing direction of the mold, and can be inserted so that the adjacent nested molds touch the wall surface. It is possible to improve the insertion workability and simplify the mold structure.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the entire molding die in the open state;
Figure 2 is a sectional view of the mold in its closed state, Figure 3 is an explanatory diagram of the movable mold seen from the parting surface, Figure 4 is an explanatory diagram showing the size of the chamfer provided at the corner of the nested mold, and Figure 5 FIG. 6 and FIG. 6 are explanatory diagrams showing other embodiments, respectively. FIG. 7 is an explanatory diagram of a conventional molding die viewed from the parting surface. 10... Model mounting plate, 12... Insertion part, 14...
Mold base, 16... Nested mold, 16a, 16b,
16c, 16d... Nested type, 18... Horizontal clamp cylinder, 20... Holding member, 22... Vertical clamp cylinder, 24... Vertical clamp, 30... Fixed type, 31... Intermediate type, 32... Movable type, 33...
Fixed plate, 34... Fixed base, 35... Limiting bolt, 36... Runner stripper plate,
37... intermediate type base, 38, 38'... nested type,
39...Restriction pin, 40...Spring, 41...
...Movable plate, 42...Movable base, 43, 43'
... nesting type, 44 ... restriction pin, 45 ... cavity, 46 ... protrusion pin, 47 ... spring,
48...Protruding rod, 49...Hot runner block, 50...Insulating material, 51...Entry hole, 52...
Nozzle, 53...Spruce bush, 54...Fixing plate, 55...Undercut portion, 56...Hot runner, 57...Resin path, 58...Through hole, 5
9,59'... recess, 60... runner, 61...
...concave groove, 62...protrusion, 63...concave groove, 64...
Clamp cylinder, 65...Horizontal clamp, 66...
...Press member, 67a, 67b...Plate spring, 68
a, 68b...T groove, 69...Vertical clamp cylinder, 70...Vertical clamp, 71a, 71b...Plate spring, 72a, 72b...Coil spring, 7
3a, 73b...hole, 74a, 74b...presser, 75a, 75b...coil spring, 76
a, 76b...presser, 77...support member, 78
a, 78b... cylinder hole, 79a, 79b...
Coil spring, 80a, 80b...Piston, 82a, 82b...Coil spring, 83
a, 83b... Piston, 84... Channel.

Claims (1)

[Claims] 1. A plurality of sets of nested molds are inserted into a set of mold bases from a direction perpendicular to the mold opening/closing direction of the molds, each of which is inserted with the wall surface in contact with an adjacent nested mold. In the molding die in which the nesting molds are pressed and fixed from the side against the reference surface in the mold base, each of the nesting molds is a nesting mold having a substantially rectangular planar shape. , each corner of the insert is chamfered by a dimension difference greater than or equal to the dimensional difference between the insert mold with the largest outer dimension and the insert mold with the smallest outer dimension, and at least one side in the space of the mold base. A molding die characterized in that a pressing means is provided for individually pressing the nested molds facing the one side.