JPH09109208A - Mold clamping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold clamping apparatus which makes it possible to attempt to simplify a side cylinder type mold clamping apparatus and to effectively release a locking mechanism after molding and to strongly open the mold. SOLUTION: A movable platen 4 is telescopically moved with respect to a stationary platen 1 by mold switching means 5 fixed to the platen 1. A clamping ram 20 having a hollow part 20a is inserted into a single-acting type clamping cylinder 18. A mechanical ram 6 is held integrally with the ram 20 by engaging the lock plate 30 of a locking mechanism 8 with the recess 7a of an engaging member 7. A distance cylinder 40 is formed at the end of the ram 6 coupled to the platen 4, and a distance piston 41 mounting with the member 7 is inserted. In the case of unlocking the mechanism 8, the piston 41 is driven to be extended to slightly retract the ram 20, then again driven to be retracted to slightly retract the ram 20, then again driven to be retracted to eliminate the contact surface pressure of the member 7 with the plate 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for an injection molding machine, and more particularly, it includes a high pressure clamping means and a mold opening / closing means, and a mechanical part is formed in a hollow portion formed in a ram of the high pressure clamping means. The present invention relates to a mold clamping device provided with a lock mechanism that inserts a ram and holds the ram of a high-pressure clamping means and a mechanical ram immovably.

[0002]

2. Description of the Related Art A general injection molding machine includes a fixed platen, a movable platen disposed opposite to the fixed platen, and a mold clamping device for driving the movable platen toward and away from the fixed platen. Is equipped with.
The mold clamping device closes the molds attached to the fixed platen and movable platen respectively, presses the molds against the resin pressure injected into the cavity formed in the molds, and molds them after the molding is completed. The mold is opened by overcoming the resistance due to the adhesion of the product. The operation of the mold clamping device is performed in the order of high speed mold closing, low speed mold closing, high pressure clamping, strong mold opening, and high speed mold opening in order to shorten the molding cycle of the injection molding machine and protect the mold.

When a simple direct pressure type mold clamping device using only a clamping cylinder having a clamping pin is used as a mold clamping device of an injection molding machine, a large diameter clamping cylinder capable of high pressure clamping. Is required,
It becomes difficult to open and close the high-speed mold, the molding cycle becomes long, and a large amount of hydraulic oil is required to be supplied into the clamping cylinder. Therefore, in order to perform reliable high pressure clamping and mold opening and closing by supplying a small amount of hydraulic oil, a clamping cylinder having a clamping pin as high pressure clamping means and a mold opening and closing means connected to a movable plate are used. , A so-called mechanical hydraulic type equipped with a side cylinder, a mechanical ram that is connected to a movable plate and has its tip inserted into a clamp pingram, and a lock mechanism that unmovably integrates the mechanical ram inserted into the clamp pingram. The mold clamping device has been conventionally known (for example, see Japanese Patent Laid-Open No. 152035/55). In this mechanical hydraulic type mold clamping device, the side cylinder is driven to move the movable platen forward and backward with respect to the fixed platen, and the mechanical ram connected to the movable platen is extended by the clamp pingram and is held by the lock mechanism. Then, high pressure clamping is performed by driving the clamping pin held integrally with the mechanical ram.

In the mechanical-hydraulic mold clamping device configured as described above, the mechanical ram is held against the restraining member of the lock mechanism in order to hold the clamping pin and the mechanical ram together to perform high-pressure clamping. Since the engaging portion is pressed and the contact surface pressure is large, it becomes difficult to release the lock mechanism.

As a conventional technique for releasing the lock mechanism, as disclosed in Japanese Patent Laid-Open No. 48-39550, there is provided a spring for urging the clamping pin so as to retract the mechanical mechanism. It is known that when the restraint member engaged with the ram is retracted to release the lock mechanism, the contact surface pressure of the mechanical ram with respect to the restraint member is eliminated to smoothly move the restraint member.

Further, as another conventional technique for releasing the lock mechanism, as disclosed in Japanese Patent Laid-Open No. 152035/1988, a lock plate is provided between the clamping cylinder and the movable plate. Is movably supported along the tie bar, and a positioning cylinder for positioning the lock plate with respect to the clamping cylinder is provided to widen the space between the clump pingram and the lock plate supporting the rotary plate as an engaging member. It is known that a spring that acts on is provided. When the mold is opened, the lock disk is moved so as to approach the clamp pingram by driving the positioning cylinder so that the tip of the mechanical ram is not in contact with the engaging member. Also, due to the reaction force of the spring, the clamp pingram and the turntable are separated from each other,
Even if the turntable is rotated, the end face of the turntable is not damaged.

[0007]

The conventional technique for releasing the above-mentioned conventional lock mechanism has a problem that the structure is complicated.

The present invention has been made in view of the above problems, and basically relates to an improvement of a mechanical hydraulic type mold clamping device as disclosed in JP-A-55-152035. The aim is to simplify by using multiple mechanical rams and positioning cylinders (driving means) independently, and to provide a mold clamping device that can reliably release the locking mechanism after molding and perform strong mold opening. To provide.

A second object of the present invention is to provide a low-cost mold clamping device capable of supporting a mechanical ram with a simple structure when the mechanical ram is long.

[0010]

In order to achieve the above object, a mold clamping device according to a first aspect of the present invention is a single-acting type liquid having rams arranged facing each other on a fixed plate and having a hollow portion formed therein. Pressure type high pressure clamping means, movable platen movably arranged between the fixed platen and high pressure platen means, and hydraulic type mold opening / closing mechanism fixedly mounted on the fixed platen to move the movable platen forward and backward with respect to the fixed platen. Means and
A mechanical ram, one end of which is connected to the surface of the movable plate facing the high-pressure clamping means and the other end of which is inserted into the hollow portion of the ram of the high-pressure clamping means, and an engagement provided at the other end of the mechanical ram. A member, a lock mechanism that engages with the engaging member so as to hold the ram of the high-pressure clamping means and the mechanical ram immovably, and a drive means that drives the engaging member forward and backward. It is a thing.

In the mold clamping device according to the second aspect of the present invention, a support roller for supporting the lower part of the mechanical ram can be provided on the ram of the high pressure clamping means.

When the mold clamping device according to the present invention is configured as described above, when molding, high-speed mold closing is performed by the retracting drive of the mold opening / closing means, and the mold opening / closing means retracts before the molds come into contact with each other. Decelerate the speed and gently close the mold.
Then, the ram of the high-pressure clamping means and the mechanical ram are integrally engaged with each other by the lock mechanism, and the injection molding is performed while the high-pressure clamping means is driven. Due to the high-pressure clamping, the lock mechanism and the engaging member press each other to increase the contact surface pressure.

After the completion of molding, the high pressure clamping is stopped, and the engaging member is driven by the driving means so as to be separated from the mechanical ram. By driving the engaging members away from each other, the ram of the high-pressure clamping means retracts. Then, when the engaging member is driven by the drive means so as to be in close contact with the mechanical ram, the lock mechanism and the engaging member are separated from each other, the contact surface pressure is eliminated, and the lock mechanism can be easily released. Further, since the single-acting high-pressure clamping means can be adopted, the structure including the circuit connected thereto can be simplified.

After that, the mold opening / closing means is driven to extend to open the mold. Since the mold opening / closing means is fixed to the fixed plate, the driving force in the extension direction is large. Therefore, the strong mold opening can be surely performed only by the mold opening / closing means. After the mold is opened, high-speed mold opening is performed by the mold opening / closing means.

When the mechanical ram is lengthened to lengthen the stroke, it is possible to support the mechanical ram from below by providing a support roller on the ram of the high pressure clamping means. The support of the mechanical ram is such that the support roller rolls below the mechanical ram when the mechanical ram extends with respect to the clamping pin. Therefore, it is not necessary to finish the surface of the mechanical ram to be smooth.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a mold clamping device according to the present invention will be described below with reference to FIGS. 1 and 2. The same reference numerals in the drawings denote the same or corresponding parts.

The mold clamping device according to the present invention is generally described as a stationary platen 1.
And a single-acting hydraulic high-pressure clamping means 2 having a ram 20 having a hollow portion 20a formed opposite to the stationary platen 1
And a tie bar 3 provided between the fixed platen 1 and the high-pressure clamping means, and a movable platen 4 movably inserted into the tie bar 3.
And a hydraulic type die opening / closing means 5 fixed to the fixed board 1 for moving the movable board 4 forward and backward with respect to the fixed board 1, and one end connected to the surface of the movable board 4 opposite to the high pressure clamping means 2. The other end of the mechanical ram 6 is inserted into the hollow portion 20a of the ram 20 of the high pressure clamping means 2, the engaging member 7 provided at the other end of the mechanical 6 and the ram 20 of the high pressure clamping means 2. And mechanical ram
The lock mechanism 8 that engages with the engaging member 7 so as to hold it immovably and the ram 20 of the high-pressure clamping means 2
And a drive means 9 for driving the mechanical ram 6 forward and backward in the longitudinal direction. Then, molds 10 and 11 are attached to the surfaces of the fixed plate 1 and the movable plate 4 that face each other, respectively.

The stationary platen 1 is formed in a substantially rectangular shape. A tapered hole 14 into which a nozzle (not shown) of a heating cylinder is inserted is formed in the center, and each corner has four corners. One end of each tie bar 3 of the book is connected by a nut 15.

The high pressure clamping means 2 is a clamping cylinder.
Clamping gram through seal member 19 at the tip opening of 18
It is a single-acting type in which a hydraulic pressure source having a surge tank 21 at the rear end is connected, with 20 inserted. Further, the cylinder chamber 18a of the clamping cylinder 18 is provided with a pressure sensor or a timer (not shown) having upper and lower limit contacts for confirming that the pressure in the cylinder chamber 18a has been released after the completion of molding. ing. The clamping cylinder 18 and the clamping pin 20 are set to have strokes that can be adjusted according to the mold thickness of the molds 10 and 11 that are mounted with a larger diameter than the mold opening / closing means 5. The other end of the tie bar 3 connected to the fixed plate 1 is connected to the clamping cylinder 18 by the nut 15.
The cramping gram 20 has a hollow portion having an opening at its tip.
20a is formed.

The movable platen 4 is formed in a substantially rectangular shape so as to be aligned with the fixed platen 1, and tie bars 3 are inserted at each corner so that the movable platen 4 can move back and forth with respect to the fixed platen 1.

The mold opening / closing means 5 has a diameter smaller than that of the high-pressure clamping means 2 and is set to have a stroke long enough to open / close the mold. The side cylinder 25 and the piston rod 26 inserted into the side cylinder 25 are used. It consists of The side cylinder 25 is fixed to the fixed platen 1, and the tip of the piston rod 26 is connected to the movable platen 4. A hydraulic pressure source common to the clamping cylinder 18 or different from the hydraulic pressure source is switchably connected to the front end portion and the rear end portion of the side cylinder 25 (not shown).

The mechanical ram 6 has one end connected to the surface of the movable platen 4 facing the clamping cylinder 18 and the other end provided in the hollow portion 20a with a clearance with respect to the tip opening of the clamping pin 20. It has been inserted.

As shown in FIGS. 1 and 2, the engaging member 7
In the case of this embodiment, an annular recess 7a is formed. On the other hand, the lock mechanism 8 is the recess of the engaging member 7.
State with clearance α for 7a ((a) of FIG. 4)
Refer to).) A pair of lock plates 30 that can be entered
And a lock cylinder 31 for moving the lock plate 30 forward and backward with respect to the recess 7a of the engaging member 7. As shown in FIG. 2, a space plate 33 and a top plate 34 having an insertion portion 32 that is movably inserted into the tie bar 3 located in the space are provided at the tip of the cramping gram 20 so that the lock plate 30 is sandwiched. Installed. It should be noted that the lock mechanism 8 may be provided so as to engage the engaging member 7 in the vertical direction as shown in FIG. 1 or may be provided in the lateral direction as shown in FIG. But it's okay. In FIG. 2, the right half shows an unlocked state in which the lock plate 30 is retracted from the recess 7a of the engaging member 7, and the left half shows the recess 7a of the engaging member 7.
The lock state in which the lock plate 30 is engaged is shown in FIG.

Further, in relation to the lock mechanism 8, it is detected that the concave portion 7a of the engaging member 7 is close to the engaging position with the lock plate 30 by the retracting drive of the mold opening / closing means 5 to detect the mold opening / closing means 5. A limit switch or an encoder (hereinafter, referred to as a low speed position setting LS) is provided as a detection unit (not shown) to set a position for reducing the retraction speed. Further, as shown in FIG. 4 (a), it is detected that the recess 7a of the engaging member 7 is at the longitudinal position with a slight gap α between the engaging member 7 and the lock plate 30, and
In order to extend and drive the lock cylinder 31 to engage the lock plate 30 with the recess 7a of the engaging member 7, a limit switch or an encoder (hereinafter referred to as an engaging member position detection LS) is provided as a detecting means (illustration). Was omitted).

Driving means 9 for driving the engaging member 7 forward and backward in the longitudinal direction of the clamp pingram 20 and the mechanical ram 6.
Is configured such that a distance cylinder 40 is formed on the other end side of the mechanical ram 6 which is inserted into the clamping pin 20 and a distance piston 41 having an engaging member 7 attached to the tip thereof is inserted into the distance cylinder 40. is there.
The circuit connected to the distance cylinder 40 is not shown.

The mechanical ram 6 of the mold clamping device according to the present invention constructed as described above is cantilevered with respect to the movable platen 4 and has a slight clearance between the mechanical ram 6 and the tip opening of the clamp pingram 20. When the mechanical ram 6 is long, the support roller 44 for supporting the mechanical ram 6 from below is provided on the surface of the movable plate side 4 of the top plate 34, as shown in FIGS. 5 and 6. Can be provided.

Further, the engaging member 7 of the mold clamping device according to the present invention
The lock mechanism 8 is not limited to the above-described configuration, and as shown in FIGS. 7 and 8, an annular groove 7b is formed in multiple lines around the entire circumference of the engaging member 7, and the lock plate 30 is provided. Instead of the ridge 50b, which engages with the groove 7b of the engaging member 7.
It is also possible to form the chuck member 50 in the form of a pair of half nuts, which are formed on the inner peripheral surface and surround the entire circumference of the engaging member 7. In this case, the groove 7b of the engaging member 7 is formed so that the side wall 7c on the side of the clamping cylinder 18 is orthogonal to the axial direction and the side wall 7d on the side of the movable plate 4 is inclined with respect to the axial direction. And chuck members
It is preferable that the protrusion 50b of the 50 is such that the side wall 50c on the top plate 34 side is orthogonal to the axial direction and the side wall 50d on the space plate 33 side is inclined with respect to the axial direction. Also in this case, similarly to the above-described embodiment, the space α shown in (a) of FIG. 8 and the side wall 7c on the movable plate side orthogonal to the axial direction of the groove 7b of the engaging member 7, It is formed between the protrusion 50b of the chuck member 50 and the side wall 50c on the top plate side orthogonal to the axial direction.

Next, the operation of the mold clamping device according to the present invention will be described with reference to FIGS. 1, 3 and 4. In addition, in this description, when the thickness of the molds 10 and 11 attached to the fixed platen 1 and the movable platen 4 is the maximum, that is, as shown in FIG. Will be explained depending on the case.

From the state shown in FIG. 1, high-speed mold closing is performed by retracting the mold opening / closing means 5. When the concave portion 7a of the engaging member 7 is close to the engaging position with the lock plate 30, the low speed position setting L
S detects and slows down the retracting speed of the mold opening / closing means 5 before the molds 10 and 11 come into contact with each other, and the molds 10 and 11 are gradually closed (FIG. 3). When it is detected by the mold closing completion position setting LS that the molds are in close contact with each other, the engagement member position detection LS causes the recess 7a of the engagement member 7 to be in contact with the lock plate 30, as shown in (a) of FIG. After detecting that there is a gap α between them, the lock cylinder 31 is driven to extend and the lock plate 30 enters the recess 7a of the engaging member 7.

When the mold closing is completed and the clamping mechanism 20 holds the clamp pingram 20 and the mechanical ram 6 together, the cylinder chamber 18a of the clamping cylinder 18 and the cylinder chamber of the side cylinder 25 on the piston rod side are retained. Pressure oil is supplied to perform high pressure clamping. When it detects that the upper limit contact of the pressure sensor of the clamping cylinder 18 has reached a predetermined pressure during this boosting, injection is started, molten resin is supplied to the cavities 10 and 11 in the mold, and injection molding is performed. .

While the high-pressure clamping is being performed, the pressing force due to the extension of the clamp pingram 20 is transmitted to the engaging member 7 via the space plate 33 and the lock plate 30, so that (b) in FIG. As shown in (), the lock plate 30 of the lock mechanism 8 and the engaging member 7 are pressed against each other, so that the contact surface pressure of both 30 and 7 is high. Therefore, when the molding is completed and the mold is opened, the supply of the pressure oil to the clamping cylinder 18 is stopped and the lower limit contact of the pressure sensor 19 or the timer is used for the cylinder chamber 18a.
After confirming that the internal pressure has been released to the specified pressure,
As shown in FIG. 4 (c), pressure oil is supplied to the cylinder chamber 40a on the right side of the distance cylinder 40 in the figure, and the distance piston 41 is extended and driven to separate the engaging member 7 from the mechanical ram 6 by a distance α. Let

The engaging member 7 is separated from the mechanical ram 6 by a distance α
By only separating them, the cramping gram 20 moves so as to retract. Then, when pressure oil is supplied to the cylinder chamber 40b on the left side of the distance cylinder 40 in the drawing to bring the engagement member 7 into close contact with the mechanical ram 6, FIG.
Similar to the state shown in Fig. 5, a gap α is formed between the engaging member 7 and the lock plate 30 of the lock mechanism 8, the contact surface pressure between the two 7 and 30 disappears, and the lock cylinder 31 is retracted to cause the lock plate 30 to retract. It is possible to retract the 30 from the recess 7a of the engaging member 7, that is, to release the lock mechanism 8.

Thereafter, the mold opening / closing means 5 is driven to extend and the mold is opened. As already known from Japanese Examined Patent Publication No. 48-17130, since the side cylinder 25 is fixedly mounted on the fixed platen 1, when the extension drive is performed, the pressure oil is supplied to the cylinder chamber on the side opposite to the piston rod 26. Supply. The cylinder chamber of the side cylinder 25 on the side opposite to the piston rod 26 has a larger pressure receiving area than the cylinder chamber on the side of the piston rod 26, so that the driving force in the extension direction is large. Therefore, the strong mold opening can be performed only by the mold opening / closing means 5, and the high pressure clamping means 2 can be a single-acting type. When it is confirmed that the molds 10 and 11 have been strongly opened by the high-speed mold opening initial position setting LS, pressure oil is further supplied to the cylinder chamber on the side opposite to the piston rod 26 of the side cylinder 25 to open the high-speed mold. To do. The clamp pingram 20 has a stroke capable of adjusting the mold thickness for a mold having a minimum to maximum mold thickness, but a detailed description of the mold thickness adjustment will be omitted.

[0034]

According to the present invention, the single-acting hydraulic high-pressure clamping means having rams facing each other on the fixed board and having the hollow portion formed between the fixed board and the high-pressure clamping means. The movable platen movably disposed on the fixed platen, hydraulic die opening and closing means fixed to the fixed platen to move the movable platen forward and backward relative to the fixed platen, and the surface of the movable platen opposite to the high pressure clamping means. The mechanical ram, one end of which is connected and the other end of which is inserted into the hollow portion of the ram of the high-pressure clamping means, the engaging member provided at the other end of the mechanical ram, the ram of the high-pressure clamping means, and the mechanical ram. By providing a lock mechanism that engages with the engaging member so as to hold it immovably, and a drive means that drives the engaging member forward and backward,
In the mechanical hydraulic type mold clamping device, unlike the double-acting high-pressure clamping device, precise machining of the inner wall of the clamping cylinder is not required, and the advance / retreat driving device for the mechanical ram and the engaging member is simplified. At the same time, it is possible to reliably release the locking mechanism after molding and perform strong die opening.

When a support roller for supporting the mechanical ram from below is provided on the movable side surface of the top plate, it is not necessary to precisely finish the surface on which the support roller of the mechanical ram rolls. The cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of a mold clamping device according to the present invention.

FIG. 2 is an explanatory view showing the operation of the lock device.

FIG. 3 is a partial cross-sectional view showing a mold closed state.

FIG. 4 is a schematic diagram of the embodiment shown in FIGS.
(A) From the state where the engaging member and the cramping gram are integrally held by the lock mechanism, (b) The lock plate and the engaging member are pressed against each other when the cramping gram is extended and driven for high pressure clamping. It is explanatory drawing which shows a state and the state which extendedly driven the (c) drive means so that an engaging member may be separated from a mechanical ram.

FIG. 5 is a partially enlarged cross-sectional view showing an embodiment of a mold clamping device in the case where a support roller that supports the mechanical ram from below is provided.

FIG. 6 is a front view of the top rate of the mold clamping device shown in FIG.

FIG. 7 is a partial enlarged cross-sectional view showing another embodiment of the engagement member and the lock mechanism.

FIG. 8 is a diagram showing the embodiment shown in FIG. 7, in which (a) the locking member integrally holds the clamping member and the clamping pingram, and (b) the clamping pingram is driven to extend and high-pressure clamped. It is an explanatory view showing a state in which the lock plate and the engaging member are pressed against each other and a state in which the engaging member is extended and driven so as to be separated from the mechanical ram by the drive means (c).

[Explanation of symbols]

 1 Fixed plate 2 High pressure clamping means 3 Tie bar 4 Movable plate 5 Mold opening / closing means 6 Mechanical ram 7 Engaging member 8 Locking mechanism 9 Driving means 10, 11 Mold 20 Clamping gram 44 Support roller

Claims (2)

[Claims] 1. A single-acting hydraulic high-pressure clamping means having rams facing each other on a fixed plate and having a hollow portion formed therein, and movably arranged between the fixed plate and the high-pressure clamping means. A movable plate, a hydraulic type mold opening and closing means fixed to the fixed plate for moving the movable plate forward and backward with respect to the fixed plate, and one end connected to the surface of the movable plate opposite to the high pressure clamping means and the other end A mechanical ram inserted into the hollow portion of the ram of the high-pressure clamping means, an engagement member provided at the other end of the mechanical ram, and a ram of the high-pressure clamping means and the mechanical ram are held immovably. A mold clamping device comprising: a lock mechanism that engages with the engagement member; and a drive unit that drives the engagement member to move back and forth. 2. The mold clamping device according to claim 1, wherein a support roller for supporting the lower side of the mechanical ram is provided on the ram of the high-pressure clamping means.