JPH0490323A - Locking apparatus for injection molding machine and the like - Google Patents

Abstract

PURPOSE:To obtain surely and with reproducibility a starting point for mold clamping without being influenced by compressibility of oil by providing an elastic member which is repulsively energized and a stretching adjustable pinching body which pinches a hydraulic clamp and a movable mold plate. CONSTITUTION:As a plurality of rods 3 are fixed on other fixing members in such a way that they are in parallel to the back and forth direction of a movable mold plate 7 and are brought into sliding contact with the outer edge of the movable plate 7, the movable plate 7 moves back and forth so as to be restricted by these fixed rods 3. In addition, a hydrauric clamp 4 which can hold these fixing rods 3 are fixed on the side face of a hydrauric cylinder for the movable mold plate 7 and it is repulsively energized to the movable mold plate 7 by means of an elastic member 5 but the movable range of the hydrauric clamp 4 by this repulsive force is within a range restricted independently by a stretching adjustable pinching body 6, namely it is only a specified dimension delta. In addition, as the pinching body 6 is stretchingly adjustable, if this required dimension delta is adjusted to be delta=0, it is applicable to an injection molding method. In addition, if it is adjusted to be deltanot equal to 0, it becomes applicable to an injection compression molding method and this required dimension delta becomes to a mold clamping range delta in the injection compression molding method.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the improvement of mold clamping devices such as injection molding machines, and relates to the improvement of mold clamping devices such as injection molding machines, which can suitably perform injection molding methods and injection compression molding methods. Related to mold clamping device.

[Conventional technology]

A mold used for shaping resin, ceramic, die casting, or other materials by mold clamping is divided into a movable mold plate and a fixed mold plate.For example, referring to FIG. A pair of split molds 71 and 81 are fixedly installed on opposing surfaces of the movable mold plate 7 and the fixed mold plate 8, respectively. The rod 12 of the hydraulic cylinder 1 is separately provided on the fixing member 2.
As the rod 12 expands and contracts, the movable mold plate 7 engaged with the end face of the rod 12 reciprocates in the direction of the fixed mold plate 8, and the divided molds 71 and 81 are brought into close contact with each other or separated from each other (hereinafter referred to as , such a configuration is called a mold clamping device of an injection molding machine, etc.), and the molding method in such a configuration is broadly classified into injection molding and injection compression molding (which method is used depends on the material of the molding material). The former injection molding method will be explained with reference to the same figure, in which oil is supplied to the chamber 11 of the hydraulic cylinder 1 and the movable mold plate 7 is After being moved in the direction of the fixed mold plate 8 and pressed to a position where the split mold 71 comes into close contact with the split mold 81 as shown by the imaginary line, the injection unit 9 passes through the passage 82 of the fixed mold plate 8. Fill the cavity 7 with materials such as resin.
This is a method of injecting and molding into 8. On the other hand, in the latter injection compression molding method, a predetermined position I near the split mold 81 is used.
After the split molding mold 71 is temporarily stopped at the clamping starting point (hereinafter referred to as the mold clamping starting point), the passage 8 of the fixed mold @ 8 is opened by the injection unit 9.
2, a material such as resin is injected into the cavity 78, and then or at the same time, the split mold 71 is replaced with the split mold 81.
This is a method of molding by pressing the mold to a position where it comes into close contact with the mold (hereinafter referred to as the mold clamping end point). Therefore, the quality of the molded product in the latter injection compression molding method depends on the mold clamping starting point (in other words,
It depends on how accurately and reproducibly the mold clamping range (from the mold clamping start point to the mold clamping end point) can be ensured. However, according to the mold clamping device of an injection molding machine or the like having the above-mentioned configuration, since there is a large amount of oil in the chamber 11 of the hydraulic cylinder 1 at the mold clamping starting point position, the movable mold is affected by the compressibility of the oil and other factors. Board 7 (
That is, the position of the split mold 71) is not stable, and it is difficult to secure the mold clamping starting point accurately and with good reproducibility.

To solve this problem, mold clamping devices such as injection molding machines used in injection compression molding have conventionally been disclosed in Japanese Patent Publication Nos. 61-5889, 58167132-5, and 58-167137, although not shown. As disclosed in , after the redivided molds are brought into close contact with each other, a stopper is inserted between the movable mold plate and the hydraulic cylinder injection mold plate, and then the movable mold plate is moved in the direction of separation of the redivided molds. A method is known in which the mold clamping starting point is determined by retracting the mold and bringing it into contact with the stopper.

Others, such as JP-A-61-283497 and JP-A-57-159300, aim to further improve the mold clamping accuracy and to facilitate adjustment of the mold clamping range. Many devices have been disclosed in which the WIIJl distance is detected using a linear scale or the like and feedback control is performed using an electro-hydraulic servo or a proportional control valve.

[Problem to be solved by the invention]

However, with the former stopper insertion method, for example, when replacing the mold, due to differences in the thickness of the split molds, the length of the bar must be adjusted each time, or stoppers of various specifications are prepared in advance. , it involves time-consuming work such as having to replace them each time. Furthermore, there are some drawbacks, such as errors in the mold clamping range due to the influence of temperature distortion of the frame. On the other hand, although the latter feedback AM requires an expensive servo control device, it is inferior in terms of reliability and cost. Therefore, in order to overcome such drawbacks, excessive quality and high cost are unavoidable, and it has not yet become mainstream in practical use.

The present invention focuses on the above-mentioned 88 points of the conventional technology, and when performing the injection compression molding method, the mold clamping starting point ( In other words, it is an object of the present invention to provide a mold clamping device for an injection molding machine or the like that can obtain a mold clamping range). Furthermore, it is an object of this mold clamping device such as an injection molding machine that it can also be used for ordinary injection molding methods.

[Means to solve the problem]

In order to achieve the above object, the mold clamping device for an injection molding machine or the like according to the present invention will be described with reference to FIGS. 1 and 2. The injection molding machine is equipped with a movable mold plate 7 and a fixed mold plate 8 provided respectively, and the movable mold plate 7 is reciprocated in the direction of the fixed mold plate 8 by a hydraulic cylinder 1 to bring the split molds 71 and 81 into close contact with each other or to separate them. In a mold clamping device such as a molding machine, a plurality of fixed rods 3 which are parallel to the reciprocating direction of the movable mold plate 7 and are in sliding contact with the outer edge of the movable mold plate 7, and hydraulic pressure of the movable mold plate 7 are used. A hydraulic clamp 4 that is installed on the cylinder 1 and can grip the fixed rod 3, an elastic member 5 that repulses the hydraulic clamp 4 and the movable mold plate 7, and the hydraulic clamp 4 and the movable mold plate 7 have the desired dimensions. The structure includes an extendable and retractable clamp 6 that clamps the hydraulic clamp 4 and the movable mold plate 7 so that they can be separated by δ.

(Function) According to the above configuration, the plurality of rods 3 are fixed to the other fixed member so as to be parallel to the reciprocating direction of the movable mold plate 7 and in sliding contact with the outer edge of the movable mold plate 7. Therefore, the movable template 7
are restrained by these fixed rods 3 and come to reciprocate. Moreover, a hydraulic clamp 4 and the like capable of gripping these fixed rods 3 are attached to the side surface of the hydraulic cylinder of the movable mold plate 7.

The hydraulic clamp 4 is repulsively biased against the movable mold plate 7 by the elastic member 5, but the movable range of the hydraulic clamp 4 due to this repulsive force is within the range restrained by the separately expandable and adjustable pincer 6. , that is, only a predetermined dimension δ. Moreover, this desired dimension δ can be adjusted to δ=0 by adjusting the expansion and contraction (δ-〇~δ) since the sandwich body 6 can be adjusted by expansion and contraction.
If adjusted, the above configuration can be applied to the normal injection molding method, and conversely, if the dimension δ is adjusted to δ≠0,
The above configuration can be applied to injection compression molding. That is, when δ≠O, this desired dimension δ becomes the mold clamping range δ in the injection compression molding method.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. As shown in FIG. 1, an injection molding machine or the like is roughly composed of mold clamping devices 1 to 8 and an injection unit 9. Specifically, one end of each rod 3 (four at the four corners in this example) is fixed to the outer edge of the fixed mold plate 8, and each rod 3 is slidably fitted into a hole in the movable mold plate 7. After that, the other end of each is fixed to a fixed member 2 of the hydraulic cylinder 1. These rods 3 are parallel to the direction of the reciprocating motion of the movable mold plate 7, and are slidably fitted into the holes of the movable mold plate 7 as described above, so that the rods 3 serve as zero-order guides for the reciprocating motion of the movable mold plate 7. The hydraulic clamp 4, the elastic member 5, and the telescopically adjustable clamp 6 are attached so as to be located on the back surface of the movable mold plate 7 (side surface of the hydraulic cylinder). To explain in detail with reference to FIG. 2, first, the hydraulic clamp 4 is constructed in a cylindrical shape so that the rod 3 is fitted therein, and in order from the inside, there are slide collars 41 at both ends, and a dust seal 42 on the outer side. A clamp 44 is mounted on the slide collar 41 and has an O-ring 43 on both ends of the outer periphery, and a pressure chamber A is placed inside the center area of the inner periphery, and a flange 451 is provided on the outer edge of the outer periphery. The zero-order elastic member (in this example, a coil spring) 8, which includes a case 45, has one end surface in contact with the flange portion 452 of the hydraulic clamp 4, and the other end surface in contact with the movable mold plate 7. The hydraulic clamp 4 and the movable mold plate 7 are repulsively biased. Next, the telescopically adjustable pincer 6
has one end that locks the outer edge of the hydraulic clamp 4 in a loosely fitted state, and the other end that is fixed to the movable mold plate 7 (not shown, but in this example, it is bolted). The telescopically adjustable pincer 6 is divided into a cap 6a at one end and a body 6b at the other end, both of which are screwed together by a female thread on the cap 6a and a male thread on the body 6b.

A means for rotating the cap 6a is attached to the outer periphery of the cap 6a. By this means camp 6a
By rotating the pin 6, the expansion and contraction of the sandwich body 6 can be adjusted. That is, as shown in the same figure, this telescopic adjustable clamp 6 allows the hydraulic clamp 4 and the movable mold plate 7 to be adjusted to a desired size δ.
It is configured such that the two are spaced apart by the same amount. When this desired dimension δ is δ≠0, this dimension δ becomes the mold clamping range δ in injection compression molding. Note that the means may be a mere lever and manually rotate the cap 6a, but in this example, in order to rotate the four hydraulic clamps simultaneously and by the same amount, the device shown in FIG. 3 is used. It has been added.

Incidentally, to explain these with reference to the same figure, the means is a sprocket 63, and the additional device is a chain 64 wound around these sprockets 63, and a motor 65 (in this example, a motor 65 for driving this chain 64 by a desired amount). By rotating this motor 65 (a pulse motor) by a desired amount, the desired dimension δ can be varied from 0 to δ.

Next, the operation of the first embodiment will be explained. In the case of the injection compression molding method, first, before starting the work, the hydraulic cylinder 1 is extended to bring the split molds 71 and 81 into close contact with each other. Next, the motor 65 is rotated to rotate the cap 6a via the chain 64, sprocket 63, and screw, and the cap 6a is moved in and out to adjust the mold clamping range δ depending on the molding material and molding shape. Mold clamping range δ required in advance
Match. Then, injection compression molding work began.

That is, the hydraulic cylinder 1 brings the divided mold plates 71 and 81 into close contact. Next, pressurized oil is introduced from the oil inlet/outlet P of the hydraulic clamp 4 to bring the pressure chamber A into a pressurized state. At this point, the inner circumference of the clamp 44 contracts to grip the rod 3. Next, the hydraulic cylinder 1 is retracted by a slight amount (>δ), and the material is injected from the injection unit 9 into the cavity 82. At this time, only the movable mold plate 7 will move back toward the hydraulic clamp 4 by the mold clamping range δ (note that due to the slight amount (>δ) of the hydraulic cylinder 1 moving back, oil will be The problem of instability at the starting point of mold clamping due to compressibility is no longer a problem in the present invention),
Thereafter or at the same time, the hydraulic cylinder 1 brings the split mold plates 71, 81 into close contact with each other again, thereby completing the injection compression molding.

On the other hand, if it is an injection molding method, unlike the injection compression molding method described above, there is no need for the process of first bringing the split molds 71 and 81 into close contact with each other, and the cap 6a is immediately rotated to close the mold clamping range δ-. ○ and the injection molding process can be started. The operation for injection molding is similar to conventional techniques.

Other examples, although not shown, are as follows, for example.

+11 The number of rods is as in the first embodiment above.
It is not necessary to limit the number to four; in short, it is sufficient to use a plurality of pieces in consideration of the shape of the mold.

(2) There is no need to hold all rods with hydraulic clamps. In short, depending on the shape of the mold, some rods may not be gripped.

(3) The hydraulic clamp, as in the first embodiment above,
It is not necessary to limit it to an inner circumferential compression type hydraulic clamp. For example, if the rod has opposing flat surfaces or if it is simply a protruding rail of a fixed strength member, a disc-type hydraulic clamp or the like which is a pinching type rather than a sliding type as in the first embodiment is suitable. The point is the mouth.

The type of clamp (shape and gripping method) may be determined based on the shape and type of the clamp.

(4) The elastic member need not be limited to a coil spring as in the first embodiment. Rubber springs, countersunk springs, plate springs, talk springs, and others may be selected as appropriate.

(5) The expandable and retractable pinch body does not need to be limited to the two-piece screw type as in the first embodiment. For example, the movable cedar board may be the body 6b itself; in this case, the movable cedar board is provided with a recess with a female thread, and the cap 6a is provided with a male thread. In addition, a slide-knock type or wedge-type clamp with a telescoping adjustment mechanism is also suitable, and the telescoping configuration can be selected as appropriate.

Next, the effects of the above embodiment will be explained. In the above embodiment, the contact point of the split mold (mold clamping end point) is essentially a fixed position. Therefore, based on this determined mold clamping end point, the position where the movable mold plate 7 retreats from this mold clamping end point, comes into contact with the hydraulic clamp 4, and stops the movable mold plate 7 (!11, mold clamping starting point) is also The position is confirmed. Therefore, unlike the conventional technology, it is no longer affected by the compressibility of oil in the hydraulic cylinder. In other words, the mold clamping range δ determined by each determined position (mold clamping end point and mold clamping starting point) is also a determined range. That is, according to the above embodiment, the mold clamping starting point (
In other words, the mold clamping range δ) can be obtained reliably and with good reproducibility. Therefore, reliable injection compression molding can be performed and the quality of the molded product can be improved. ) can be freely changed. If the mold clamping range δ is adjusted to δ-0, the device of the above embodiment can be applied to ordinary injection molding. Moreover, in this case, the biasing force of the elastic member 5 is the most Therefore, when the mold is clamped, this biasing force is added to the thrust of the hydraulic cylinder 1, and an increase in mold clamping force can be expected.Of course, even if there are differences in the thickness of various molds, the conventional Unlike the stopper insertion method, there is no need to replace or replace the device M (for example, a hydraulic clamp in this example) for regulating the mold clamping starting point.

〔Effect of the invention〕

As explained above, according to the mold clamping device for an injection molding machine or the like according to the present invention, when performing the injection compression molding method, the mold clamping device has a simple configuration, is not affected by the pressure testability of oil, and can reliably perform the injection compression molding method. Moreover, the mold clamping starting point and mold clamping range δ can be set with good reproducibility. Furthermore, normal injection molding can be easily carried out. The details are as follows.

(1) The structure is simple and can be constructed at low cost by simply adding a hydraulic clamp or the like to a mold clamping device such as a normal injection molding machine.

(2) In the injection compression molding method, the mold clamping end point is determined by the close contact position of the two sub molds, and the mold clamping starting point is determined based on this mold clamping end point, making it easy to set the mold clamping range. , can be set reliably and with good reproducibility. In other words, the quality of injection compression molded products can be significantly improved.

(3) Since the mold clamping range can be adjusted, even if the mold thickness is changed, a new mold clamping range can be immediately reset. Further, by setting the mold clamping range δ=0, it becomes possible to apply the method to a normal injection molding method.

(4) Since the biasing force of the elastic member is added to the pushing force of the hydraulic cylinder, it is possible to improve the mold clamping force. In particular, if the injection molding method is used in the mold clamping range δ=0, the effect of this action is significant.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a first embodiment of a mold clamping device for an injection molding machine or the like according to the present invention, FIG. 2 is a cross-sectional view of an example of a hydraulic clamp used in the first embodiment, and FIG. FIG. 4 is a schematic configuration diagram of an example of driving the expandable and retractable sandwich body used in the example, and FIG. 4 is a sectional view of an example of a mold clamping device of a conventional injection molding machine or the like. 1... 3... 4... 5... 6... 7... 8... 71.81. δ・・・・Hydraulic cylinder・・Fixed rod・Hydraulic clamp・Elastic member・Extensible adjustable clamp・Movable mold plate・Fixed mold plate・Divided mold,・・Designed dimensions (p!l tightening range)

Claims (1)

[Claims] A movable mold plate 7 and a fixed mold plate 8 are provided, each of which has a pair of split molds 71 and 81 on opposing surfaces, and the movable mold plate 7 is reciprocated in the direction of the fixed mold plate 8 by a hydraulic cylinder 1. In a mold clamping device such as an injection molding machine that at least brings the split molds 71 and 81 into close contact with each other or separates them from each other, it is parallel to the reciprocating direction of the movable mold plate 7 and is brought into sliding contact with the outer edge of the movable mold plate 7. A plurality of fixed rods 3, a hydraulic clamp 4 provided on the hydraulic cylinder 1 side of the movable mold plate 7 and capable of gripping the fixed rod 3, and an elastic member 5 that biases the hydraulic clamp 4 and the movable mold plate 7 in repulsive force. An injection molding machine characterized by a configuration comprising: and a telescoping adjustable clamp 6 that clamps the hydraulic clamp 4 and the movable mold plate 7 so that the hydraulic clamp 4 and the movable mold plate 7 can be separated by a desired dimension δ. etc. mold clamping device.