JP2884051B2 - Mold clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping apparatus for an injection molding machine, and more particularly to a mold clamping apparatus and a mold opening / closing means. The present invention relates to a mold clamping device provided with a lock mechanism that penetrates a ram and immovably holds a ram of a high-pressure clamping unit and a mechanical ram.

[0002]

2. Description of the Related Art A general injection molding machine includes a fixed plate, a movable plate disposed opposite to the fixed plate, and a mold clamping device for driving the movable plate close to and away from the fixed plate. It has.
The mold clamping device closes the mold attached to each of the fixed platen and the movable platen, and presses the mold with high pressure against the resin pressure injected into the cavity formed in the mold. The mold is opened by overcoming the resistance caused by 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 pressing, strong mold opening, and high-speed mold opening in order to shorten the molding cycle of the injection molding machine and protect the mold.

[0003] When a simple direct pressure type clamping device using only a clamping cylinder having a clamping gram is used as a clamping device of an injection molding machine, a large diameter clamping cylinder capable of high pressure clamping. Is required,
It is difficult to open and close the high-speed mold, and the molding cycle is lengthened, 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 opening and closing of the mold by supplying a small amount of hydraulic oil, a clamping cylinder having a clamp pingram as high-pressure clamping means and a mold opening / closing means connected to a movable platen are used. A so-called mechanical hydraulic system having a side cylinder, a mechanical ram connected to a movable platen and having a tip inserted into a clamping gram, and a lock mechanism for immovably integrating the mechanical ram inserted into the clamping gram. Is conventionally known (see, for example, Japanese Patent Application Laid-Open No. 55-152035). In this mechanical hydraulic type mold clamping device, the movable plate is moved forward and backward with respect to the fixed plate by driving the side cylinder, and the state where the mechanical ram connected to the movable plate is extended with respect to the clamp gram is held by the lock mechanism. Then, high-pressure pressing is performed by driving the clamp gram held integrally with the mechanical ram.

[0004] In the mechanical hydraulic type clamping device constructed as described above, the clamping ram and the mechanical ram are integrally held and high-pressure clamping is performed. Is pressed, so that the contact surface pressure is large, and it is difficult to release the lock mechanism.

As a conventional technique for releasing the lock mechanism, as disclosed in Japanese Patent Laid-Open Publication No. 48-39550, a mechanical spring is provided to bias the clamp gram backward. There is known a configuration in which, when the lock member is released by retracting the restraint member engaged with the ram, the contact surface pressure of the mechanical ram against the restraint member is eliminated and the restraint member is smoothly moved.

As another conventional technique for enabling the lock mechanism to be released, as disclosed in Japanese Patent Application Laid-Open No. 55-152035, a lock plate is provided between a clamping cylinder and a movable plate. Is movably supported along the tie bar, and a positioning cylinder is provided for positioning the lock disc with respect to the clamping cylinder, so that the distance between the clamp pingram and the lock disc supporting the rotary disc as an engagement member is increased. There is known a spring provided with a spring acting on the spring. When the mold is opened, the lock plate is moved so as to approach the clamp gram by driving the positioning cylinder, so that the tip of the mechanical ram is not in contact with the engaging member. In addition, the clamping force and the turntable are separated by the reaction force of the spring,
Even when the rotating disk is rotated, the end surface of the rotating disk is not damaged.

[0007]

The prior art for enabling the above-mentioned conventional lock mechanism to be released 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 mold clamping device as disclosed in Japanese Patent Application Laid-Open No. 55-152035. The aim is to provide a mold clamping device that simplifies by using a plurality of mechanical rams and positioning cylinders (driving means) alone, and that can reliably release the locking mechanism after molding and strongly open the mold. To provide.

It is a second object of the present invention to provide a low-cost mold clamping device which can support a mechanical ram with a simple structure when the mechanical ram is long.

[0010]

According to a first aspect of the present invention, there is provided a mold clamping apparatus comprising a ram having a hollow portion and a ram disposed opposite to a fixed plate. Pressure type high-pressure pressing means, a movable plate movably arranged between the fixed plate and the high-pressure pressing means, and a hydraulic die opening and closing fixed to the fixed plate and moving the movable plate with respect to the fixed plate. Means,
A mechanical ram having one end connected to the surface of the movable plate facing the high-pressure pressing means and the other end inserted into the hollow portion of the ram of the high-pressure pressing means; and an engagement provided at the other end of the mechanical ram. A member, a lock mechanism for engaging the engaging member so as to immovably hold the ram and the mechanical ram of the high-pressure pressing means, and a driving means for driving the engaging member forward and backward. Things.

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

When the mold clamping apparatus according to the present invention is formed as described above, when molding, high-speed mold closing is performed by retraction driving of the mold opening / closing means, and the mold opening / closing means is retracted before the dies contact each other. Reduce the speed and close the mold gently.
Then, the ram of the high-pressure pressing means and the mechanical ram are integrally engaged by the lock mechanism, and injection molding is performed with the high-pressure pressing means driven. Due to the high-pressure pressing, the lock mechanism and the engagement member press against each other to increase the contact surface pressure.

After the molding is completed, 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. The ram of the high-pressure pressing means is retracted by the separation driving of the engaging member. When the engagement member is driven by the driving means so as to be in close contact with the mechanical ram, the lock mechanism and the engagement member are separated from each other, the contact surface pressure is eliminated, and the lock mechanism can be easily released. In addition, since a single-action type high-pressure pressurizing means can be adopted, the structure including the circuit connected thereto can be simplified.

Thereafter, 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, strong mold opening can be reliably performed only by the mold opening / closing means. After the mold is opened, high-speed mold opening is performed by mold opening and closing means.

When the mechanical ram is lengthened in order to lengthen the stroke, the mechanical ram can be supported from below by providing a support roller on the ram of the high-pressure pressing means. In the support of the mechanical ram, when the mechanical ram extends with respect to the clamping gram, the support roller rolls below the mechanical ram. Therefore, it is not necessary to finish the surface of the mechanical ram smoothly.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a mold clamping device according to the present invention will be described below with reference to FIGS. The same reference numerals in the drawings denote the same or corresponding parts.

The mold clamping device according to the present invention generally comprises a fixed platen 1
And a single-acting hydraulic high-pressure pressing means 2 having a ram 20 with a hollow portion 20a formed opposite to the fixed platen 1.
And a tie bar 3 provided between the fixed plate 1 and the high-pressure pressing means, and a movable plate 4 movably inserted through the tie bar 3.
One end is connected to the surface of the movable platen 4 facing the high-pressure pressing means 2 with the hydraulic die opening / closing means 5 fixed to the fixed platen 1 to move the movable platen 4 forward and backward with respect to the fixed platen 1. The mechanical ram 6 has the other end inserted into the hollow portion 20a of the ram 20 of the high-pressure pressing means 2, the engaging member 7 provided at the other end of the mechanical 6, and the ram 20 of the high-pressure pressing means 2. And mechanical ram
And a locking mechanism 8 that engages with the engaging member 7 so that the engaging member 6 is immovably held.
And a driving means 9 for driving the mechanical ram 6 to move forward and backward in the longitudinal direction. Then, dies 10 and 11 are attached to the opposing surfaces of the fixed platen 1 and the movable platen 4, respectively.

The fixed 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 4 holes are formed in each corner. One end of each tie bar 3 is connected by a nut 15.

The high-pressure pressing means 2 is a clamping cylinder.
Clampgram via seal member 19 at the tip opening of 18
20 is a single-acting type in which a hydraulic source having a surge tank 21 at the rear end is connected. The cylinder chamber 18a of the clamping cylinder 18 is provided with a pressure sensor or a timer (not shown) having upper and lower contacts for confirming that the pressure in the cylinder chamber 18a has been released after the molding is completed. ing. The clamping cylinder 18 and the clamping pingram 20 are set to have a stroke that can be adjusted according to the thickness of the molds 10 and 11 that are attached with a larger diameter than the mold opening / closing means 5. In the clamping cylinder 18, the other end of the tie bar 3 connected to the fixed board 1 is connected by a nut 15.
Clampgram 20 is a hollow part with 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 into each corner so as to be able to advance and retreat with respect to the fixed platen 1.

The mold opening / closing means 5 has a smaller diameter than the high-pressure clamping means 2 and is set to have a stroke long enough to open and close the mold, and has a side cylinder 25 and a piston rod 26 inserted through the side cylinder 25. It is composed of The side cylinder 25 is fixed to the fixed board 1, and the tip of the piston rod 26 is connected to the movable board 4. A hydraulic source common to the clamping cylinder 18 or another hydraulic source is switchably connected to the front and rear ends of the side cylinder 25 (not shown).

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

As shown in FIG. 1 and FIG.
In this embodiment, an annular concave portion 7a is formed. On the other hand, the lock mechanism 8 is
7a with clearance α (FIG. 4 (a)
) And a pair of lock plates 30
And a lock cylinder 31 that moves the lock plate 30 forward and backward with respect to the concave portion 7a of the engagement member 7, respectively. At the tip of the clamping gram 20, as shown in FIG. 2, a space plate 33 and a top plate 34 having an insertion portion 32 that is movably inserted into a tie bar 3 located in the gap are sandwiched by the lock plate 30. Installed. The locking mechanism 8 may be provided so as to engage the engaging member 7 from the up and down direction as shown in FIG. 1 or to be engaged from the left and right direction as shown in FIG. May be. 2, the right half shows an unlocked state in which the lock plate 30 is retracted from the concave portion 7a of the engaging member 7, and the left half shows the concave portion 7a of the engaging member 7.
2 shows a locked state in which the lock plate 30 is engaged.

In connection with the lock mechanism 8, the retracting drive of the mold opening / closing means 5 detects that the concave portion 7a of the engaging member 7 has approached the engagement position with the lock plate 30, and In order to set a position at which the retraction speed is reduced, a limit switch or an encoder (hereinafter, referred to as a low-speed position setting LS) is provided as detection means (not shown). Further, as shown in FIG. 4A, it is detected that the concave portion 7a of the engaging member 7 is at the longitudinal position where there is a slight gap α between the engaging member 7 and the lock plate 30.
A limit switch or an encoder (hereinafter, referred to as an engagement member position detection LS) is provided as detection means for extending the lock cylinder 31 to engage the lock plate 30 with the concave portion 7a of the engagement member 7 (illustration shown). Was omitted).

Driving means 9 for driving the engaging member 7 forward and backward in the longitudinal direction of the clamping gram 20 and the mechanical ram 6.
A distance cylinder 40 is formed on the other end side of the mechanical ram 6 that is inserted into the clamp pingram 20, and a distance piston 41 having an engaging member 7 attached to the tip is inserted through 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 configured as described above has a small clearance between the movable platen 4 and the opening of the tip of the clamp gram 20 in a cantilever state. In the case where the mechanical ram 6 is long, as shown in FIGS. 5 and 6, the support roller 44 for supporting the mechanical ram 6 from below on the surface of the movable platen 4 of the top plate 34, as shown in FIGS. 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, as shown in FIGS. Instead, the ridge 50b engaging with the groove 7b of the engagement member 7
Can be formed on the inner peripheral surface to form a pair of half nut-shaped chuck members 50 that 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 clamping cylinder 18 side is orthogonal to the axial direction and the side wall 7d on the movable platen 4 side is inclined with respect to the axial direction. And chuck member
The 50 ridges 50b desirably have the side wall 50c on the top plate 34 side orthogonal to the axial direction and the side wall 50d on the space plate 33 side inclined with respect to the axial direction. Also, in this case, similarly to the above-described embodiment, the interval α shown in FIG. 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 this description, it is assumed that the thickness of the molds 10 and 11 attached to the fixed platen 1 and the movable platen 4 is maximum, that is, as shown in FIG. Will be described.

The high-speed mold closing is performed by the retraction drive of the mold opening / closing means 5 from the state shown in FIG. The low-speed position setting L indicates that the concave portion 7a of the engagement member 7 has approached the engagement position with the lock plate 30.
When S is detected, the retraction speed of the mold opening / closing means 5 is reduced before the molds 10 and 11 come into contact with each other, and the molds 10 and 11 are gently 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 concave portion 7a of the engagement member 7 to contact the lock plate 30 as shown in FIG. After detecting that the lock cylinder 31 is at the position having the gap α therebetween, the lock cylinder 31 is extended and driven to cause the lock plate 30 to enter the concave portion 7a of the engagement member 7.

When the mold closing is completed and the clamp gram 20 and the mechanical ram 6 are integrally held by the lock mechanism 8, the cylinder chamber 18a of the clamping cylinder 18 and the cylinder chamber on the piston rod side of the side cylinder 25 are moved to the cylinder chamber 18a. Supply high pressure oil to perform high pressure compression. In the course of this pressure increase, when it is detected that the upper limit contact of the pressure sensor of the clamping cylinder 18 has reached a predetermined pressure, injection is started, molten resin is supplied to the cavities of the molds 10 and 11, and injection molding is performed. .

When the high-pressure clamping is being performed, the pressing force due to the extension of the clamp gram 20 is transmitted to the engaging member 7 via the space plate 33 and the lock plate 30. ), The lock plate 30 of the lock mechanism 8 and the engagement member 7 press against each other, so that the contact surface pressure between the two 30 and 7 is high. Therefore, when molding is completed and the mold is opened, the supply of pressure oil to the clamping cylinder 18 is stopped, and the lower limit contact of the pressure sensor 19 or a timer is used to release the cylinder chamber 18a.
After confirming that the internal pressure has been released to the specified pressure,
As shown in FIG. 4C, pressure oil is supplied to the right cylinder chamber 40a in the drawing of the distance cylinder 40, and the distance piston 41 is extended to drive the engaging member 7 away from the mechanical ram 6 by a distance α. Let it.

The engaging member 7 is separated from the mechanical ram 6 by a distance α.
With only a separation, the clamping gram 20 moves to retract. When pressure oil is supplied to the left cylinder chamber 40b in the figure of the distance cylinder 40 to bring the engagement member 7 into close contact with the mechanical ram 6, FIG.
A gap α is formed between the engagement member 7 and the lock plate 30 of the lock mechanism 8 as in the state shown in FIG. 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 to open the mold. As is already known in Japanese Patent Publication No. 48-17130, the side cylinder 25 is fixed to the fixed platen 1 so that the pressure oil is supplied to the cylinder chamber on the opposite side of the piston rod 26 during the extension drive. Supply. The cylinder chamber on the side of the side cylinder 25 opposite to the piston rod 26 has a larger pressure receiving area than the cylinder chamber on the piston rod 26 side, and therefore has a large driving force in the extension direction. Therefore, strong mold opening can be performed only by the mold opening / closing means 5, and the high-pressure pressing means 2 can be a single-acting mold. When it is confirmed that the molds 10 and 11 have been strongly opened by the high-speed mold opening initial position setting LS, further pressurized oil is 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. Do. Although the clamping gram 20 has a stroke capable of adjusting the mold thickness with respect to the mold from the minimum to the maximum mold thickness, a detailed description of the mold thickness adjustment is omitted.

[0034]

According to the present invention, there is provided a single-acting hydraulic high-pressure pressing means having a ram having a hollow portion disposed opposite to a fixed plate, and between the fixed plate and the high-pressure pressing means. A movable plate fixedly mounted on the fixed plate, a hydraulic type opening / closing means for moving the movable plate forward and backward with respect to the fixed plate, and a movable plate having a surface opposed to the high-pressure pressing means. A mechanical ram having one end connected and the other end inserted into the hollow portion of the ram of the high-pressure pressing means, an engaging member provided at the other end of the mechanical ram, and a ram and a mechanical ram of the high-pressure pressing means. By providing a lock mechanism that engages with the engagement member so as to hold it immovably, and a driving unit that drives the engagement member forward and backward,
A mechanical hydraulic type mold clamping device does not require the precision machining of the inner wall of a clamping cylinder unlike a double-acting high-pressure clamping means, and simplifies a mechanism for moving a mechanical ram or an engaging member forward and backward. At the same time, it is possible to reliably release the lock mechanism after molding and open the strong mold.

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. Costs can be reduced.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing an operation of a lock device.

FIG. 3 is a partial sectional view showing a state in which a mold is closed.

FIG. 4 is a cross-sectional view of the embodiment shown in FIGS.
(A) From the state where the engaging member and the clamp gram are integrally held by the lock mechanism, (b) the lock plate and the engaging member when the clamp gram is extended and driven to perform high-pressure pressing are pressed against each other. It is explanatory drawing which shows a state and (c) the state which extended and driven so that an engaging member might separate from a mechanical ram by the drive means.

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

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

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

FIG. 8 shows the embodiment shown in FIG. 7, in which (a) the engaging member and the clamp gram are integrally held by the lock mechanism, and (b) the clamp gram is extended and driven to perform high-pressure pressing. It is an explanatory view showing a state where the lock plate and the engaging member are pressed against each other and a state where the engaging member is extended and driven by the driving means so as to be separated from the mechanical ram.

[Explanation of symbols]

 1 Fixed platen 2 High pressure clamping means 3 Tie bar 4 Movable platen 5 Mold opening and closing means 6 Mechanical ram 7 Engaging member 8 Lock mechanism 9 Driving means 10, 11 Mold 20 Clamp pingram 44 Supporting roller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-86062 (JP, A) JP-A-5-74825 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 45/64-45/68 B29C 33/20-33/24 B22D 17/26

Claims (2)

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