JP3091707B2 - Turntable structure of vertical injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a turntable structure of a vertical injection molding machine.

[0002]

2. Description of the Related Art There is already known a vertical injection molding machine in which a tie bar is attached to a turntable for mounting a die by penetrating the tie bar.

FIG. 3 shows the structure of a turntable of a three-bar type vertical injection molding machine as an example. Note that FIG.
3A is a plan view showing the periphery of the turntable 101 by horizontally cutting the vertical injection molding machine slightly above the turntable 101, and FIG.
Tie bar 100 with turntable 101
FIG. 3 is a side cross-sectional view showing only a peripheral portion of the turntable 101 by dividing the turntable 101 by a plane including a central axis of FIG.

[0004] As shown in FIG.
A ring-shaped external gear 103 fixed to the lower surface of the turntable 101 is attached to the outer periphery of the tie bar 100 so that the center of rotation is aligned with the axis of the tie bar 100, and is rotatably and axially immovable via a bush 102. It is rotationally driven via a pinion 104 of a table rotation servomotor 105.

FIG. 3 shows an example of a two-stage type turntable 101, in which two lower dies 106a and 106b, which form a part of an injection molding die, are one.
It is mounted on the turntable 101 at a pitch of 80 °. In the state of FIG. 3, the stage on the side with the lower mold 106a is a mold clamping stage, and the stage on the side with the lower mold 106b is a product take-out stage.

Although not particularly shown in FIG. 3, a platen for mounting the upper mold, a mold clamping mechanism, a mold thickness adjusting mechanism, an injection mechanism, and the like are provided so as to be vertically overlapped with the mold clamping stage. I have. Further, a through hole for projecting a push rod of an ejector unit provided below the turntable 101 is provided at the center of the lower mold mounting position of each stage on the turntable 101, and the turntable 101 The lower mold 106a and the lower mold 106 are formed by the upward and downward movement of the push rod.
The product release operation from b is performed.

There are, of course, three-stage and four-stage turntables 101, but the outline of the configuration is the same as in the example of FIG. For reference, FIG. 4 shows the structure of a turntable of a four-tie bar type vertical injection molding machine. The point that the turntable 101 is attached with one of the tie bars 100 as the center of rotation is the same as in the case of the three-tie bar type vertical injection molding machine shown in FIG.

In the case of this type of vertical injection molding machine, since a plurality of lower dies are arranged on a concentric circle, the turntable 101 is not used.
There is a problem that the diameter required for installing the vertical injection molding machine increases as the diameter increases.

Of course, if the diameter of the turntable 101 is reduced, the installation space of the vertical injection molding machine can be reduced. However, it is difficult to mount a large lower die simply by reducing the diameter of the turntable 101. In addition, there is a problem in that the tie bar intervals are close to each other and the mounting accuracy of the lower die mounting position is required to be severe.

[0010]

An object of the present invention is to reduce the diameter of a turntable without changing the size of a lower mold that can be mounted, and to provide a turntable structure for a vertical injection molding machine that requires less installation space. To provide.

[0011]

The present invention has three or more tie bars, and the turntable is rotatably mounted on a turntable for mounting a mold by penetrating one of the tie bars. A vertical injection molding machine, wherein the center of the turntable is offset with respect to the center of a tie bar penetrating the turntable toward a center of a polygon having each tie bar as a vertex. Achieved.

Further, as one means for mounting the turntable offset from the center of the tie bar penetrating the turntable, a cylindrical shaft having a through hole eccentric from a central axis is provided, and the cylindrical shaft is inserted through the through hole. The present invention proposes a configuration in which the turntable is rotatably mounted on the cylindrical shaft so that the center of rotation of the turntable coincides with the center axis of the cylindrical shaft.

Further, in order to reduce the size of the vertical injection molding machine as a whole, a hollow speed reducer provided with an input shaft and an output shaft concentrically is mounted around the outer periphery of the cylindrical shaft, and the output shaft is provided. Is connected to the turntable, the input shaft is connected to a drive source via a power transmission mechanism, and the turntable is rotationally driven via the hollow reduction gear.

The hollow speed reducer is mounted so as to be slidable relative to the axial direction of the tie bar, and the turntable is mounted rotatably and immovably in the axial direction with respect to the base of the injection molding machine. , Stable mold clamping force can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a main part of a vertical injection molding machine according to an embodiment to which a turntable structure of the present invention is applied, that is, a periphery of a turntable 101, and FIG.
1A, the vertical injection molding machine is cut horizontally slightly above the turntable 101 to show the periphery of the turntable 101 in the same manner as in the conventional example shown in FIG. Then, the turntable 101 is divided by a plane including the center axis of the tie bar 100 on which the turntable 101 is mounted, among the three tie bars 100, and the turntable 10
1 shows a peripheral portion of FIG. FIG. 1C is a perspective view showing an outer shape of a cylindrical shaft 2 attached to a tie bar 100 on which a turntable 101 is attached.

As shown in FIG. 1B, the turntable 1
Reference numeral 01 denotes a single tie bar 100 via a cylindrical shaft 2 (see FIG. 1C) having a through hole 1 eccentric from the central axis, a bush 3 located on the outer peripheral portion of the cylindrical shaft 2 and a hollow reduction gear 4. And is slidably and non-sinkably mounted on a top plate 6 of a base of a vertical injection molding machine via a disk-shaped sliding plate 5 made of an oil-less metal or the like. ing. In addition, rotation between the bush 3 attached to the hollow reduction gear 4 and the cylindrical shaft 2 and sliding in the axial direction are free, and the cylindrical shaft 2 rotates to the tie bar 100 through the through hole 1. And it is fixed so that it cannot move in the axial direction.

The eccentric direction of the cylindrical shaft 2 when attaching the cylindrical shaft 2 to the tie bar 100 penetrating the turntable 101 is as shown in FIG. 1A, and the center of the cylindrical shaft 2 is three tie bars. The center of the polygon with each 100 as the vertex (in this case the centroid of an equilateral triangle)
It is mounted so as to be offset toward. Since the turntable 101 is mounted with the center axis of the cylindrical shaft 2 aligned with the center axis, as a result, the turntable 10
One rotation center is offset to the center side of the polygon having each of the three tie bars 100 as a vertex.

The three tie bars 100 shown in FIG.
1 is the same as that of the conventional example shown in FIG.
In the embodiment of (a), in order to avoid interference between the turntable 101 and the two tie bars 100 on the near side, FIG.
As compared with the conventional example shown in FIG.
It is necessary to reduce the radius of 1 substantially by an amount equivalent to the offset amount (d) described above.

Therefore, as a result, the vertical length (depth in the normal state) of the vertical injection molding machine in FIG. 1A is offset compared to the conventional example shown in FIG. 3A. The length (width in the normal position) of the vertical injection molding machine in FIG. 1 (a) is reduced by the sum (2d) of the amount (d) and the diameter reduction (d). FIG.
As compared with the conventional example shown in FIG.
In other words, the diameter is reduced by the diameter reduction (2d) of the diameter of 1.

Of course, if only the mounting space of the vertical injection molding machine is intended to be reduced, the radius of the turntable 101 as shown in FIG. 3A is equivalent to the above-mentioned offset amount (d). The diameter of the turntable 101 is reduced by an amount corresponding to the diameter of the turntable 101, and three tie bars 10 are formed.
1, the same effect as in the embodiment of FIG. 1 can be obtained. However, in this case, the interval between the three tie bars 100 becomes closer in accordance with the reduction in the diameter of the turntable 101, and the lower die 106a of the lower die 106a can be mounted. There is a problem that the size is reduced. Naturally, if the diameter of only the turntable 101 is reduced without changing the interval between the three tie bars 100, the mounting position of the lower mold 106a is reduced.
, And the tie bar 100 is moved closer to the side of the tie bar 100, so that a normal mold clamping operation cannot be performed.

Also, as described above, the turntable 10
Turntable 10 having a reduced radius of 1
Even if the three tie bars 100 are rearranged in accordance with the size of 1 and the injection molding work is performed only for the small mold 106a, a slight position when the lower mold 106a is attached due to the close tie bar interval. There arises a problem that the deviation affects the variation of the mold clamping force.

In the embodiment shown in FIG. 1A, FIG.
The interval between the tie bars 100 is the same as that of the conventional example shown in (a), and the rotation center of the turntable 101 is set at the center side of the three tie bars 100 by an amount equivalent to the diameter reduction amount (d) of the turntable 101. The tie bars 100 are arranged at the same intervals as in the conventional example, and the size of the lower mold 106a that can be mounted is not reduced. Of the offset amount (d) in the vertical and horizontal directions in the projected area in the horizontal plane.
d) can be reliably reduced. Further, the interval itself between the tie bars 100 is assured as in the conventional example, and the relative positional relationship between the lower mold 106a and the three tie bars 100 is maintained in the same manner as in the conventional example.
Due to the miniaturization of 1, the problem that the positioning error at the time of attaching the lower mold 106a affects the variation of the mold clamping force is also solved.

The base of the vertical injection molding machine is formed in a housing shape so as to enclose a servo motor 105 for rotating the table and an ejector unit (not shown), but FIG. Only the part of the plate 6.

In addition, a mold clamping mechanism is provided between the rear platen provided below the top plate 6 and the top plate 6, and the moving platen provided above the top plate 6 and the turntable 101 and the rear platen are connected to each other by three. The tie bar 100 is used to integrally fasten the rear platen and the top plate 6
When the moving platen is moved toward and away from the turntable 101 to perform the mold-clamp opening operation (hereinafter, referred to as a first mold-clamping method), the housing-shaped Three tie bars 100 on the bottom plate of the base
Is fixed, and a rear platen is fastened to the tip thereof. A moving platen is provided between the rear platen and the turntable 101 and slidably attached to the three tie bars 100. In some cases, the moving platen is directly moved toward and away from the turntable 101 by the mold clamping mechanism provided in the above to perform the mold clamping mold opening operation (hereinafter, referred to as a second mold clamping method). Of course, in each case, turntable 1
The lower mold of the injection mold is mounted on the upper surface of the moving latin 01, and the upper mold is mounted on the lower surface of the moving latin.

As shown in FIG. 1B, the bush 3 interposed between the inner peripheral portion of the hollow reduction gear 4 and the outer peripheral portion of the cylindrical shaft 2 makes the axis of the tie bar 100 relative to the hollow reduction gear 4. Since the directional movement is allowed, even when the tie bar 100 slides up and down with respect to the top plate 6 and the turntable 101 at the time of closing and opening the mold when the first mold clamping method is applied, the hollow reduction gear is used. 4 and the turntable 101 are not affected by the vertical movement of the tie bar 100. In addition, in either case of applying the first and second mold clamping methods, the tie bar 100 expands and contracts during the mold opening mold clamping operation, but the hollow reduction gear 4 and the turntable 101 cause the specific tie bar 100 to expand and contract. Since the tie bars are not restrained, the three tie bars can be uniformly stretched, and a stable and stable mold clamping operation can be performed.

The hollow reduction gear 4 referred to here means, in short,
A reduction gear having a large reduction ratio having an input shaft and an output shaft concentrically, and includes, for example, a planetary gear device and an “RV reduction device” developed by Teijin Machinery. The most suitable of these is the "RV reduction gear", because
Since half of the external gear module of the reduction gear always meshes with the internal gear module, one-half as compared with other reduction gears.
This is because the force applied to one module can be small, which is advantageous in terms of accuracy and durability.

As shown in FIG. 1B, a cylindrical input shaft 8 is included inside the output shaft 7 of the hollow reduction gear 4,
Further, the bush 3 is mounted on the inner peripheral surface of the input shaft 8 to allow the rotation of the input shaft 8 relative to the cylindrical shaft 2 and the relative axial movement thereof, and the casing 9 of the hollow reduction gear 4 is vertically injection-molded. It is fixed to the top plate 6 of the machine base with bolts or the like. Of course, whether the input shaft 8 is included inside the output shaft 7 or the output shaft 7 is included inside the input shaft 8 is a matter of design, and either method may be adopted. FIG.
(B) does not show the structure itself of the planetary gear device or the “RV reduction device”, but merely shows the relative positional relationship between the input shaft 8 and the output shaft 7.

As shown in FIG. 1B, the cylindrical input shaft 8 is integrally provided with a driven pulley 10 protruding from a lower end of a casing 9 to form a timing belt 11 and a driving pulley serving as a power transmission mechanism. A rotary table 10 is rotatably driven by a servo motor 105 for rotating the table via a rotary shaft 12.
1 are integrally fixed by bolts or the like. Of course, instead of the timing belt 11, a gear train or the like can be diverted as a power transmission mechanism for transmitting the rotational driving force from the servo motor 105 to the input shaft 8.

By adopting the hollow reducer 4, FIG.
As shown in FIG. 3A, a speed reduction mechanism for rotating and driving the turntable 101 is arranged in a cohesive manner in the vicinity of the outer peripheral portion of the tie bar 100. Therefore, as shown in FIG. 3A and FIG. Unlike the conventional example, it is not necessary to fix the large-diameter external gear 103 serving as a speed reduction mechanism on the back surface side of the turntable 101, and a hole for penetrating a push rod or the like of an ejector unit is provided in the turntable 101. It can be freely drilled at any position above. As a matter of course, in the conventional example of FIGS. 3A and 4A, the external gear 103
A hole cannot be formed at a position penetrating through the tooth portion.

Further, since the turntable 101 is directly supported by the top plate 6 of the base via the sliding plate 5, a strong mold can be obtained without increasing the thickness of the turntable 101 itself and securing rigidity. It can deal with the tightening force. As a result, the thickness of the turntable 101 can be made thinner than the conventional one, which is useful for reducing the total inertial mass of the driven elements (reducing the cycle time of table rotation, etc.).

Further, the tie bar 1 penetrating the hollow speed reducer 4
00 (cylindrical shaft 2) can freely slide up and down without interference from the hollow reduction gear 4,
A turntable 101 is attached to a bush 102 attached to the tie bar 100 so as to be rotatable and immovable in the axial direction.
The tie bar 100 is different from the conventional example of FIG. 3B and FIG.
It is possible to apply the first mold clamping method described above, which slides with a large stroke in the up and down direction with respect to 1. The specific tie bar 100 mounted is a turntable 101 or a hollow reduction gear 4
The tie bar 100 is not restrained by the mounting, so that the amount of expansion and contraction of the three tie bars 100 can be kept uniform and an accurate mold opening mold clamping operation can be realized.

As described above, in one embodiment, three tie bars 1 are used.
The vertical injection molding machine equipped with 00 has been described as an example,
The configuration of the above-described embodiment is also applied to a vertical injection molding machine as shown in FIG. 4, that is, a vertical injection molding machine having four tie bars 100 in an equilateral square shape. be able to.

However, in the example of FIG. 4, since the interval between the two tie bars 100 located on the left and right is larger than the diameter of the turntable 101, the turntable 101 is reduced by applying the offset configuration of the above-described embodiment. Even if the diameter is increased, the width of the vertical injection molding machine in the projected area in the horizontal plane cannot be reduced (the width in the vertical direction can be reduced). If it is necessary to reduce the width of the vertical injection molding machine, it is necessary to reduce the width of the turntable 101 as shown in FIG.
In (a), the interval between the two tie bars 100 located on the left and right may be reduced.

Next, referring to FIG. 2, an embodiment of a four-tie-bar type vertical injection molding machine in which the vertical injection molding machine is downsized by directly applying the same turntable drive system as the conventional one will be described. A brief description will be given.

First, the arrangement and structure of the tie bar 100 are the same as those of the conventional example shown in FIG.
3 and FIG. 4 also shows that the turntable 101 is rotationally driven via an annular external gear 103 fixed to the lower surface of the turntable 101 and a pinion 104 of a servomotor 105 for rotating the table. Same as the example.

The difference from the conventional one is that the turntable 101 has a cylindrical shaft 2 having a through hole 1 eccentric from the center axis (see FIG. 1C) and a bush located on the outer peripheral portion of the cylindrical shaft 2. One tie bar 10 through 3
This is a point that is rotatably attached to zero. The bush 3 and the cylindrical shaft 2 can rotate and slide in the axial direction freely, and the cylindrical shaft 2 is fixed to the single tie bar 100 via the through hole 1 so as not to rotate and move in the axial direction. Have been.

The eccentric direction of the cylindrical shaft 2 when the cylindrical shaft 2 is attached to the single tie bar 100 is as shown in FIG. 2A, and the center of the cylindrical shaft 2 is the four tie bars 100. Are attached so as to be offset toward the center of the polygon (in this case, the centroid of the diamond) having each of the vertices as vertices. Since the turntable 101 is mounted with the center axis and the center axis of the cylindrical shaft 2 aligned, as a result, the rotation center of the turntable 101 becomes 4
It will be offset toward the center of the polygon having each of the book tie bars 100 as its apex.

Assuming that this offset amount is (d), FIG.
As in the case of the three tie-bar type vertical injection molding machine described in the above description, the vertical length of the vertical injection molding machine in FIG. 4
As compared with the conventional example shown in (a), the overall size can be reduced by (2d), and the vertical injection can be performed while maintaining the size of the lower die 106a that can be mounted on the turntable 101 as in the conventional example. The overall size of the molding machine can be reliably reduced.

Of course, the external gear 1 of the embodiment shown in FIG.
The hollow speed reducer 4 as shown in the embodiment of FIG. 1 may be adopted in place of the pinion 03 and the pinion 104 to drive the turntable 101 to rotate.

[0040]

According to the present invention, the turntable can be reduced in diameter without changing the size of the lower mold that can be mounted, and the installation space of the vertical injection molding machine can be saved.

[Brief description of the drawings]

FIG. 1 is a view showing a main part of a vertical injection molding machine according to an embodiment to which a turntable structure of the present invention is applied (when a three-tie bar and a hollow speed reducer are employed).

FIG. 2 is a view showing a main part of a vertical injection molding machine according to another embodiment to which the turntable structure of the present invention is applied (when a four-tie bar and a conventional drive system are adopted).

FIG. 3 is a view showing a main part of a conventional turntable structure (in the case of three tie bars).

FIG. 4 is a view showing a main part of a conventional turntable structure (in the case of four tie bars).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Through-hole 2 Cylindrical shaft 3 Bush 4 Hollow reduction gear 5 Sliding plate 6 Base top plate 7 Output shaft 8 Input shaft 9 Casing 10 Follower pulley 11 Timing belt 12 Drive pulley 100 Tie bar 101 Turntable 102 Bush 103 External gear 104 Pinion 105 Servo motor for table rotation 106a Lower die 106b Lower die

Claims (4)

(57) [Claims] 1. A vertical injection molding machine having three or more tie bars, wherein one of the tie bars penetrates a turntable for mounting a mold and the turntable is rotatably mounted. A turntable structure for a vertical injection molding machine, characterized in that the center of the turntable is offset with respect to the center of a tie bar penetrating the turntable toward the center of a polygon having each tie bar as a vertex. 2. A cylindrical shaft having a through hole eccentric from a central axis is provided, and the cylindrical shaft is mounted around the one tie bar through the through hole and attached to the one tie bar, and the turn is attached to the central axis of the cylindrical shaft. 2. The turntable structure of a vertical injection molding machine according to claim 1, wherein said turntable is rotatably mounted on said cylindrical shaft so that the center of rotation of said table coincides. 3. A hollow reduction gear having an input shaft and an output shaft concentrically mounted and mounted on the outer periphery of the cylindrical shaft, and the output shaft is connected to the turntable, while the input shaft is connected to the power transmission. 3. The turntable structure of a vertical injection molding machine according to claim 2, wherein the turntable is connected to a drive source via a mechanism, and the turntable is rotationally driven via the hollow reduction gear. 4. The hollow reduction gear is mounted so as to be slidable relative to the axial direction of the tie bar, and the turntable is mounted rotatably and immovably in the axial direction with respect to the base of the injection molding machine. The turntable structure of a vertical injection molding machine according to claim 3, wherein the turntable structure is provided.