JPS59185639A - Direct pressure type mold clamping apparatus of injection molding machine - Google Patents

Abstract

PURPOSE:To issue the accuracy of a platen parallel degree and to make it possible to keep the parallel degree, by setting a clearance to such a degree that a rod and a bearing part can form an oil film while communicating the ring shaped oil groove provided to the bearing part with the chamber of a mold clamping cylinder through the clearance. CONSTITUTION:The oil groove 20 of a bearing part 5 is filled with oil in a ring shape and a thin oil film is formed to a clearance 21. A rod 3 supports a movable side platen 12 and a mold 13 in a cantilevered state and the parallel degree of the plten 12 is kept without generating the eccentricity of said platen by the oil film. In clamping the mold 13, the rod 3 becomes large in a cantilever support distance with the advance thereof but, because the oils and oil films in the oil grooves 20, 24 are automatically aligned against the increase of side pressure and, at the same time, two-point support is performed, the horizontal degree of the rod 3 itself is accurately kept and the parallel degree of the platen is always kept succeedingly. In opening the mold, a valve 7 is opened and oil pressure is acted on a chamber while oil pressure is supplied to the oil grooves 20, 24 through the clearances 21, 25 to form a thin film and the parallel degree of the platen is succeedingly kept even in a mold open region.

Description

[Detailed Description of the Invention] ill Technical Field of the Invention The present invention relates to a mold clamping device for an injection molding machine or a die casting machine, and more particularly to a structure for ensuring parallelism of a platen in a horizontal direct pressure mold clamping device. It is.

(2) Prior art and its problems Traditionally, direct pressure type mold clamping devices such as injection molding machines have a mold clamping cylinder 7 placed horizontally on the head, and tights <- in the forward and backward direction of the mold clamping cylinder. A movable side and a platen of fixed height j are arranged through the platen.

Further, a movable platen is provided on the rond of the mold clamping cylinder, and the bearing portion of the rond is constituted by a bund having a clearance of at least about 30 microns that allows the ront to move forward and backward. Therefore, due to the weight of the movable platen and the mold attached to it, the iron is eccentric within the bearing clearance range, and at the same time the tie bar is deflected, which in turn causes the grana/
This caused the parallelism of the plane to go out of order. If the parallelism of the grating is out of alignment, the guide bins of the mold will be subject to uneven loads and wear out, and the molds will not be properly aligned, which will shorten the life of the mold. I ended up losing it.

In order to overcome the above drawbacks, the quiver has been made to have a large diameter to minimize deflection, or a sliding root sound has been interposed between the lower surface of the movable platen and the vent. In the former case, there is naturally a limit to increasing the diameter of the tie bar.

When the tie bar is made larger in diameter, the mold mounting surface of the platen is narrowed by the larger diameter. For this reason, it is undesirable to expand the entire area of the grating because the overall load will increase. The tie bar can only be made large in diameter within a range not restricted by the mold mounting surface.

In the case of the latter, it is necessary to ensure the parallelism of three points: the rod of the mold clamping cylinder, the fixed grating, and the movable platen with the sliding plate. Since the vent of the main body is not necessarily horizontal and there is clearance in the bearing part, the parallelism of the north, upper a, three, and ton is strictly d in machining.
Even if it is assumed that the O parallelism, which cannot be achieved by Δ, is accurately obtained, firstly, the sliding plate is affected by the heat of the molding cycle, and a monthly error occurs. Second, the sliding plate has a clearance between it and the vent, which is necessary for C1M movement! 7) In addition, due to metal contact with the bed, there will be wear due to metal contact with the bed.
]Adjust 1 core 1] to the top level 7! 'L must be 7'' 1. Thirdly, the sliding plate 5i + 1 must be replaced with the mold ((1). In any case, the Lagrana parallelism is 2. The maximum degree is 50 microns and 75 degrees, and it cannot be guaranteed for a long time;・t0 Therefore,
Currently, the molds were matched in total 11 times based on the error in the tension force ∆ and the parallelism of the metal platen.

By the way, in modern times, the development of ennnia non-gloss plastics has reached a level of perfection (at Celsius, precision on the order of microns is now required).

In order to meet this demand, the mold is made in minutes! II jU
It must be an absolute condition that the combinations are exactly the same. Mold f: Even if finished precisely,
If there is an error in mold matching, molding on the order of 11 microns is impossible. In this sense, the parallelism of the conventional platen described above is limited to a maximum of 50 microns, so it cannot be applied to molds for precision parts requiring accuracy of 10 microns or less.

In view of the above circumstances, the applicant
The company provides equipment related to this issue. This is an annular oil groove provided in the bearing part of the rod of the mold clamping cylinder (by applying pressure oil, it creates a self-aligning structure for the amount of advance and retreat of the rod, as well as a structure that is controlled by the rigidity of the rod. This maintains the horizontality of the movable platen.According to this, the rod was self-aligned by applying pressure oil to the oil groove and adjusting the forward and backward movement clearance, but the results of various experiments have shown that it is not necessary to supply pressure oil. It has been found that the oil skin layer can be maintained even without oil. In other words, in the viscous region, the skin layer is formed as an extremely thin oil film. This clearance B is used to communicate the oil groove with the chamber of the mold clamping sill. In this case, the forward and backward movement of the rod can function as oil O flow. ,
The entire skin layer as a boundary layer can be formed in the clearance.

(3) Purpose of the Invention The present invention was developed in view of the above-mentioned circumstances.
-f parallelism over a long period of time? The purpose is to be able to maintain it without going crazy.

(4) Features of the invention Features of the present invention to improve the above object (1) The bearing part of the rod of the mold clamping cylinder is provided with an oil groove, and the rod and bearing part are covered with an oil film. The above-mentioned oil groove is communicated with the chamber of the above-mentioned mold clamping cylinder through this clearance. I will explain next.

(5) Drawings of an embodiment of the invention (t) Showing an embodiment of a mold clamping device for an injection molding machine or the like according to the present invention, Fig. 1 is a partially cutaway schematic diagram showing the opening limit of type 1d, and Fig. 2 3 and 4 are enlarged cross-sectional views of the same essential parts -ζ.

The drawings show that it is implemented as a booster ram type.

In the figure, 1 is the mold clamping cylinder, 2 is the mold decoration ram, 3 is the rod of the mold clamping ram 2, 4 is the piston of the mold clamping ram 2, and 5 is the rod 3
bearing part, 6 is a flange of bearing part 5, 7 is a valve, 8I
'i Booster ram, 9, 10. 11 is a chamber where oil acts, 12 movable side platens, 13 is movable side platen 12
14 is a stationary platen, 15 is a die attached to the stationary platen 14, and 16 is a tie bar. This horizontal structure direct pressure type mold clamping device is known as 2nd type.

The bushing of the bearing portion 5 is made entirely of a material such as carbon fiber having high wear resistance, and a balancing groove 20 as an oil groove is provided on the inner circumferential surface of the bushing. A large number of balancing grooves 20 are provided on the inner circumferential surface of the bushing in the shape of a circular worm so as to surround the rod 3, and are formed in a 7-shaped cross section with an appropriate gap. In addition, the balancing groove 20 is not provided at one end in the axial direction of the bushing 7, and a mold is provided in the axial direction -Qg through the clearance 21 between the outer circumferential surface of the rod 3 and the inner circumferential surface of the bearing portion 5. It communicates with the chamber 11 of the tightening cylinder 1.

The clearance 21 is set to a minute gap size that allows a thin oil film to be formed. The machining accuracy (depends on the machine, but specifically it is set to about 15 microns or less, and the craftsmanship is about 5 microns or more. Both ends of the bushing in the axial direction are soles. The seals are 21 examples of Ehan Lupa. A seal 22 and a dust seal 23 are applied.

Similarly, another balancing groove 24 is provided on the outer circumferential surface of the piston 4 of the clamping ram 2. Balancing groove 2
4 is not provided at both axial ends of the piston 4, and communicates with each chamber 10.11 via a clearance 25. The clearance 25 is set to such an extent that a thin oil film can be formed.

Further, the piston 4 is provided with a ball bearing 26 as a roller bearing on its inner peripheral surface.

Similarly, a ball bearing 27 is provided in most of the sliding portion between the tie bar 16 and the movable platen 12. Since the ball bearings 26 and 27id can be used in a no-load state, those with high dimensional accuracy are selected.

Based on the above-mentioned structure, the operation will be described. The balancing groove 20 of the bearing portion 5 is filled with oil in an annular shape, and a thin oil film is formed in the clearance 21. Similarly, annular oil and an oil film are formed in the balancing groove 24 of the piston 4 and the clearances 25.25 at both ends thereof, so that the thrust of the rod 3 in the axial direction is
The state is close to no load. The rod 3 has rigidity due to its large diameter, which allows it to be connected to the movable platen 12 and the mold 13.
The movable platen 12 and the mold 13 are maintained parallel &' without eccentricity due to the oil film. Due to this hydraulic balance, the tie bar 16 is not subjected to the load of the movable platen 12 and the mold 13.

Next, when the mold is clamped, when hydraulic pressure is applied to the chamber 9 of the booster ram 8 in the mold closing region, the rod 3 immediately moves forward because the rod 3 is in a nearly unloaded state.

As the rod 3 moves forward, the oil film in the clearance 21 is
Acting as a boundary layer, the oil is replenished in the balancing groove 20 in an entrained state. Similarly, in the balancing groove 24 and the clearance 25 of the piston 4, a thin oil film acts as a boundary layer. The ball hair ring 28 of the movable platen 12 is guided by the Kuinoku-16 and moves without being subjected to its own weight. As the rod 3 moves forward, the cantilever support angle becomes a dog, but as the workmanship increases, the oil and oil film in the balancing grooves 20... and 24... are self-centering and at the same time, the two points Since it is supported, the horizontality of the rod 3 itself is still maintained precisely. The rigidity of the rod 3 is such that it does not affect the parallelism between the movable 1UII platen 12 and the mold 13. Therefore, the rod 3 always maintains parallelism from the low-speed mold closing region to the high-pressure mold closing region. Positioning is done in two lines.

The mold 13 of the movable side platen 12 is the same as that of the fixed side platen 1.
The gold of No. 4 and the gold of No. 15 fit together with their mating surfaces accurately matching. During this time, chamber 1 o VC oil is sucked in from HARZ 7.

When opening the mold, the valve 7 opens and hydraulic pressure is applied to the chamber 11. Hydraulic pressure is supplied to the balancing groove 20 of the bearing part 5 and the balancing groove 26 of the piston 4 (from the d chamber 11 through each clearance 21.25, and a thin oil film is formed. Therefore, the piston 4 The rod 3 responds to the mold clamping ram 2 and the mold is opened.As the mold clamping ram 2 retreats, the oil film acts as a boundary layer, so the parallelism of the platen is adjusted to the extent that the mold opens. continues to be maintained in this area.

(6) Another embodiment of the invention In the above embodiment, a V-shaped groove 2 is provided on the outer peripheral surface of the piston 4.
6 has been described, however, the outer peripheral surface may have a sliding contact structure without providing this V-shaped groove 26.

In addition, in the above embodiment, the booster ram type is shown in the figure;
＜ However, it goes without saying that the invention is not limited to this. It can be implemented in a direct pressure mold clamping device consisting of a mold clamping cylinder, a platen, and a quiver, such as an auxiliary cylinder type, a pressure boosting cylinder chamber, etc.

Further, although the cylinder 27 is shown as an example in the above embodiment, it can also be implemented by configuring it as a base bearing. In this case, an oil film *24 may be provided on the inner peripheral surface of the bearing hole of the flat bearing.

(7) Effect of invention According to the present invention, the following effects are achieved.

(B) Rod bearing part (A ring-shaped oil groove is provided, and the clearance of the bearing part is set to such an extent that an oil film can be formed. The oil groove is communicated with the mold clamping cylinder chamber through this clearance. Therefore, the oil film can be applied as the rod advances and retreats, and there is no need to provide a special pressure oil supply structure, which greatly simplifies the structure and achieves manufacturing cost reduction.

(Li) The rod was supported horizontally by the oil film and the small clearance that allowed this oil film to form, and the rigidity of the rod made it possible to accurately maintain the horizontality of the movable platen and the mold.The amount of advance and retreat of the rod. Due to the self-aligning effect of the oil film, the parallelism of the platen could always be set uniformly in response to the lateral pressure.As a result, it was possible to maintain parallelism of approximately 10 microns or less, making it possible to maintain precision parts. It can be applied to molds to enable precision molding.

Since an oil film acts on the rod and the bearing, high-speed opening and closing with no backlash is possible when the rod is almost under no load, and it is also possible to perform slow-speed feeding with very low pressure. In the conventional closed storage area, low-speed feeding was performed with a large load, but since slow-speed feeding can be performed with a small pressure, there is an advantage that foreign object detection can be performed accurately.

2) Since the platen is cantilever-supported by the rigidity of the rod, the tie bar can be made thinner and the mold area can be enlarged.

(e) Since there is no metal contact between the rod and the bearing,
No wear occurs even after long-term use, and the parallelism of the platen can be maintained without deviation over a long period of time. Furthermore, even if the weight of the mold changes, it is self-centering, so fine adjustments are not necessary.

[Brief explanation of drawings]

The drawings show an embodiment of the mold clamping device for an injection molding machine or the like according to the present invention, and FIG. 1 is a schematic cutaway diagram of the same part showing the mold opening, and FIG.
The figure is a schematic cutaway view of the same part showing the mold opening, and FIGS. 3 and 4 are enlarged sectional views of the same essential parts. DESCRIPTION OF SYMBOLS 1... Mold clamping cylinder, 2... Mold clamping ram, 3... Rod, 5... Rod bearing part, 12... Movable side platen, 14... Fixed side platen, 16...・Tie bar, 20.24...2 [11F? , 21.25... Clearance, 27.28... Roller bearing. Patent applicant Yoshi Yoshi, patent attorney representing Technoplus Co., Ltd. 1) Haru Yoshi

Claims (1)

[Claims] (1) A movable platen is provided on the rond of a horizontally arranged mold clamping cylinder, and the movable platen is configured to open and close the mold to the fixed platen via tie bars. In a direct pressure type mold clamping device such as a molding machine, an annular oil groove is provided in the bearing part of the rond, and a clearance is set to the extent that an oil film can be formed between the rond and the bearing part, and the oil is released through this clearance. A direct pressure type mold clamping device for an injection molding machine, etc., characterized in that a groove communicates with a chamber of the mold clamping cylinder. (2. A direct pressure type mold clamping device for an injection molding machine or the like, characterized in that an annular oil groove is provided on the outer periphery of the piston of the mold clamping cylinder in the device according to claim 1. ) A direct pressure type mold clamping device for an injection molding machine or the like, wherein a rolling bearing is provided in the sliding portion between the movable platen and the tie bar.