JP3098440B2 - 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. 2 shows, as an example, the structure of a turntable of a three-tie bar type vertical injection molding machine. Note that FIG.
2A 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.
Is mounted on the outer periphery of the tie bar 100 via a bush 102 so as to be rotatable and non-movable in the axial direction, and an annular external gear 103 fixed to the lower surface of the turntable 101.
And pinion 1 of table rotation servomotor 105
The turntable 101 is driven to rotate via the drive unit 04.

FIG. 2 shows an example of a two-stage type turntable 101, in which two lower dies 106a and 106b, which constitute 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. 2, the stage with the lower mold 106a is a mold clamping stage, and the stage with the lower mold 106b is a product take-out stage. Although not particularly shown in FIG. 2, 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. 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 product release operation from the lower mold 106a and the lower mold 106b is performed by the projecting and retracting operation of the push rod upward.

Of course, there are also three-stage and four-stage turntables 101, but the configuration is similar to that of the example of FIG. For reference, FIG. 3 shows the structure of a turntable of a four-tie bar type vertical injection molding machine.

In the case of a vertical injection molding machine in which a plurality of lower molds are mounted on the turntable 101 to perform an injection molding operation, the total weight of the turntable 101 and the lower mold becomes large.
In order to surely rotate the turntable 101, it is necessary to take a considerably large reduction ratio between the servomotor 105 and the turntable 101.

In the example shown in FIGS. 2 and 3, as a means for increasing the reduction ratio between the servomotor 105 and the turntable 101, the large-diameter external gear 103 on the turntable 101 side and the servomotor 105 are used. The combination with the pinion 104 on the side is adopted, but there is a limit in reducing the diameter of the pinion 104, and the external gear 10
Increasing the diameter of 3 causes a problem that the external gear 103 interferes with a through hole for projecting the push rod of the ejector unit on the turntable 101 or the ejector unit itself.

Of course, the external gear 103 has a relatively small diameter,
Although it is possible to perform multi-stage deceleration by interposing a gear train between the pinion 104 and the pinion 104, there is a problem that the overall structure is complicated and play is increased.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a structure in which a gear interferes with a through hole on a turntable from which a push rod of an ejector unit projects and an ejector unit, or employs a complicated gear train. An object of the present invention is to provide a turntable structure of a vertical injection molding machine which can easily rotate and drive the turntable without complicating the structure.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a vertical injection molding machine in which a tie bar is penetrated and mounted on a turntable for mounting a mold, and a hollow reduction gear having an input shaft and an output shaft concentrically. Attach and attach to the outer circumference of the tie bar,
The output shaft is connected to the turntable, while 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 above object has been achieved by the configuration.

Further, 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.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram 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 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.

As shown in FIG. 1B, the turntable 1
Numeral 01 is rotatably mounted on one tie bar 100 via a bush 102 mounted on the inner peripheral surface side of the hollow reduction gear 1 and the hollow reduction gear 1, and further, is formed of a disc-shaped disk made of oilless metal or the like Is mounted on the top plate 3 of the base of the vertical injection molding machine via the sliding plate 2 so as to be freely rotatable and non-sinkable. In addition, the sliding in the axial direction between the bush 102 attached to the hollow reduction gear 1 side and the tie bar 100 is free.

The base of the vertical injection molding machine is formed in a housing 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 3.

Note that a mold clamping mechanism is provided between the rear platen provided below the top plate 3 and the top plate 3, and the moving platen provided above the top plate 3 and the turntable 101 and the rear platen are connected to each other. The tie bar 100 is used to integrally fasten the rear platen and the top plate 3
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, a tie bar 10 for the hollow reduction gear 1 is provided by a bush 102 interposed between the inner peripheral part of the hollow reduction gear 1 and the outer peripheral part of the tie bar 100.
0 is allowed in the axial direction, so that the tie bar 100 moves the top plate 3 and the turntable 101 when closing and opening the mold when the first mold clamping method is applied.
In contrast, even when the tie bar 100 slides greatly up and down, the hollow reduction gear 1 and the turntable 101 are not affected by the vertical movement of the tie bar 100. Further, in any of the first and second mold clamping systems, the tie bar 100 expands and contracts during the mold opening mold clamping operation. However, the hollow speed reducer 1 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 1 referred to here is, 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 4 is included inside the output shaft 5 of the hollow reduction gear 1,
Furthermore, a bush 102 is mounted on the inner peripheral surface of the input shaft 4 to allow the input shaft 4 to rotate relative to the tie bar 100 and to move in the axial direction relative to the tie bar 100. Is fixed to the top plate 3 of the base with bolts or the like.
Of course, whether the input shaft 4 is included inside the output shaft 5 or the output shaft 5 is included inside the input shaft 4 is a matter of design, and either method may be adopted. FIG. 1B 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 4 and the output shaft 5.

As shown in FIG. 1B, the cylindrical input shaft 4 is integrally provided with a driven pulley 7 protruding from a lower end of a casing 6, and a timing belt 8 and a driving pulley serving as a power transmission mechanism. 9 and is driven to rotate by a table rotation servomotor 105.
On the output shaft 5 side, a disk-shaped turntable 101 is integrally fixed with bolts or the like. Of course, a gear train or the like can be used instead of the timing belt 8 as a power transmission mechanism for transmitting the rotational driving force from the servo motor 105 to the input shaft 4.

By adopting the hollow reduction gear 1, FIG.
As shown in FIG. 2A, a speed reduction mechanism for rotationally driving the turntable 101 is aggregated and provided in the vicinity of the outer peripheral portion of the tie bar 100. Therefore, as shown in FIG. 2A 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. 2A and 3A, 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 3 of the base via the sliding plate 2, 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 1
00 can freely slide up and down and expand and contract without interference from the hollow reduction gear 1, so that the turntable 101 can rotate freely and cannot move in the axial direction on the bush 102 attached to the tie bar 100. The tie bar 100 is different from the conventional example of FIGS. 2B and 3B in which the tie bar 100 is attached and the turntable 101 is supported by the tie bar 100 itself.
It is possible to apply the above-described first mold clamping method in which the tie bar 100 slides with a large stroke in the vertical direction with respect to 1. The specific tie bar 100 mounted is a turntable 101 or a hollow reduction gear 1
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, as one embodiment, three tie bars 1
The vertical injection molding machine equipped with 00 has been described as an example,
The configuration of the above-described embodiment can be applied to a vertical injection molding machine as shown in FIG. 3, that is, a vertical injection molding machine having four tie bars 100 in the same manner as described above.

[0025]

According to the present invention, since the speed reduction mechanism for rotating and driving the turntable is aggregated and provided near the outer peripheral portion of the tie bar, a through hole for projecting the push rod of the ejector unit is provided. It can be drilled at an arbitrary position on the turntable, and there is no obstruction on the lower surface of the turntable, so that interference with the ejector unit and the like can be prevented. In addition, since a hollow speed reduction mechanism that is compactly integrated and housed in the casing is adopted, it is possible to hold the lubricant inside, and it is not necessary to frequently perform maintenance work such as greasing. Get better.

Furthermore, since the axial movement of the tie bar with respect to the hollow speed reducer is allowed, the extension of the tie bar generated when the mold clamping mold is opened is not restricted by the mounting of the hollow speed reducer or the turntable. A stable mold clamping operation can be performed while keeping the expansion and contraction of the tie bar uniform, and since the turntable is directly supported by the base of the injection molding machine, the turntable can be thinned and measured. As a result, the rotation speed of the turntable can be increased (eg, the cycle time of the table rotation can be shortened).

[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.

FIG. 2 is a view schematically showing a turntable structure of a three-tie bar type vertical injection molding machine (conventional example).

FIG. 3 is a schematic view (conventional example) of a turntable structure of a four-tie bar type vertical injection molding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow reduction gear 2 Sliding plate 3 Base top plate 4 Input shaft 5 Output shaft 6 Casing 7 Follower pulley 8 Timing belt 9 Drive pulley 100 Tie bar 101 Turntable 102 Bush 103 External gear 104 Pinion 105 Servomotor 106a Lower mold 106b Lower mold

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/00-45/06

Claims (2)

(57) [Claims] 1. A vertical injection molding machine having a tie bar penetrated and mounted on a turn table for mounting a mold, wherein a hollow reduction gear having an input shaft and an output shaft concentrically is mounted around the outer periphery of the tie bar. The output shaft 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. Features a turntable structure of a vertical injection molding machine. 2. 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 the vertical injection molding machine according to claim 1, wherein the turntable structure is provided.