JP3843158B2 - Device for preventing falling of mold clamping device in injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fall prevention device for a mold clamping device in an injection molding machine, and more particularly to a fall prevention device for an end housing of a mold clamping device.
[0002]
[Prior art]
A generally used toggle type mold clamping device of an injection molding machine will be described with reference to the drawings. FIG. 2 is an overall configuration diagram of the double toggle type mold clamping device, and FIG. 3 is an enlarged cross-sectional view of a main part of FIG.
[0003]
In FIG. 2, the fixed platen 1 and the end housing 3 are connected by four tie bars 4 at a predetermined interval. The movable platen 2 is slidably provided on these tie bars 4. A fixed mold 15 is attached to the fixed platen 1 and a movable mold 16 is attached to the movable platen 2.
[0004]
The double toggle mechanism includes a first link 7 having one end pivotally attached to the movable platen 2 via a first toggle pin 10, and the other end of the first link 7 via a second toggle pin 11 and a third toggle pin 12 on both sides thereof. And a second link 8 pivotally attached to the end housing 3, and a third link 9 pivotally attached to the middle of the second link 8 and the crosshead 6 on both sides thereof via a fourth toggle pin 13 and a fifth toggle pin 14, respectively. It consists of and.
[0005]
A mold clamping cylinder 5 is attached to the end hanging 3, and its piston rod 5 a passes through the end housing 3 and is attached to the cross head 6. As shown in FIG. 3, the end housing 3 is provided with a through hole 31 into which the tie bar 4 is inserted, and the front end portion of the through hole 31 has a small diameter and serves as a support portion 32 of the tie bar 4. . The through hole 31 is slightly larger in diameter than the tie bar diameter except for the support portion 32.
[0006]
A triangular screw 34 is formed as a threaded portion of the tie bar 4 at the end of the tie bar 4 penetrating the end housing 3, and the triangular screw 34 can be rotated by an adjustment body 35 on the back surface of the end housing 3 and axially. A tie bar nut 36 provided so as not to move is screwed. A gear is formed on the outer peripheral portion of each tie bar nut 36 and is simultaneously driven to rotate by a mold thickness adjusting motor (not shown) provided in the end housing 3. The end housing 3 can be moved back and forth by a wheel provided at a lower portion thereof.
[0007]
In the above-described configuration, when pressure oil is supplied to the rear chamber of the mold clamping cylinder 5, the piston rod 5a advances in the right direction in the figure, and the forward force of the piston rod 5a is transmitted from the cross head 6 via the double toggle mechanism. It is transmitted to the movable platen 2, and the movable platen 2 is similarly advanced in the right direction, and the fixed mold 15 and the movable mold 16 are clamped as shown in FIG. Further, when pressure oil is supplied to the front chamber of the mold clamping cylinder 5, the mold is opened by an operation opposite to the above operation.
[0008]
When the mold thickness is adjusted by exchanging the mold, the tie bar nut 36 is rotated by the mold thickness adjusting motor with the toggle mechanism extended. As a result, the movable platen 2 moves along with the end housing 3 along the tie bar 4, and the distance between the movable platen 2 and the fixed platen 1 is adjusted.
[0009]
[Problems to be solved by the invention]
Since the end housing of the conventional mold clamping apparatus is connected to the tie bar only through the support portion, when the mold opening / closing operation is performed by operating the toggle mechanism, the end housing is supported on the support portion by the reaction force. May tilt. When the end housing is tilted, the movable plate that is integrated with the end housing via the toggle mechanism tilts in the same manner, and the tie bar is also bent, so that the mold guide pins that center both molds are galling. It may happen. Further, when mold clamping and molding are performed using a mold having a poor cavity balance, the end housing integrated with the movable plate is inclined due to the biased injection pressure acting on the cavity, and the movable plate is inclined. Then, the mold attached to the movable plate is inclined, and the opening of the parting surface of the mold varies depending on the direction, and a molded product with poor accuracy may be obtained.
[0010]
The present invention has been made to solve the above-described problems, and prevents the end housing from falling down due to the reaction force of the opening / closing operation of the mold clamping device of the injection molding machine and protects the mold. An object is to make the opening of the parting surface of the mold uniform during molding.
[0011]
[Means for Solving the Problems]
The present invention has solved the above-described problems as follows. In the mold clamping apparatus for adjusting the mold thickness by moving the end housing back and forth by screwing a tie bar nut provided in the axial direction on the back of the end housing to the thread portion of the tie bar formed at the end of the tie bar, The screw portion of the tie bar is a trapezoidal screw, and the end portion of the tie bar is provided at two locations: a support portion provided at the front end portion of the through hole of the end housing into which the tie bar is inserted and a spacer provided at the rear end portion. To support.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the injection molding machine according to the present invention, the mold clamping apparatus is prevented from falling, and the front end portion of the through hole of the end housing into which the end portion of the tie bar is inserted has a small diameter to be a support portion of the tie bar. A spacer for supporting a screw portion of the tie bar is provided at the side end portion, and the screw portion of the tie bar is a trapezoidal screw. A tie bar nut that is screwed with a trapezoidal screw of the tie bar and cannot be moved in the axial direction is provided on the back surface of the end housing.
[0013]
【Example】
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part showing a fall prevention device for a mold clamping device in an injection molding machine according to the present invention. In addition, since the structure and effect | action of the mold clamping apparatus of the injection molding machine by this invention are the same as the content demonstrated with reference to FIG. 2 in the column of the prior art, the description is used.
[0014]
As shown in FIG. 1, the end housing 3 is provided with a through hole 21 into which the tie bar 4 is inserted, and a front end portion of the through hole 21 has a small diameter and serves as a support portion 22 of the tie bar 4. Yes. A spacer 23 is fitted into the rear end portion of the through hole 21 and is similarly used as a support portion of the tie bar 4.
[0015]
A trapezoidal screw 24 as a threaded portion of the tie bar 4 is formed at the end of the tie bar 4 penetrating the end housing 3, and the trapezoidal screw 24 can be rotated by an adjustment body 25 on the back surface of the end housing 3 and is axial A tie bar nut 26 that is immovably provided is screwed onto the screw. The trapezoidal screw 24 of the tie bar 4 is fitted to the spacer 23 so as to be movable back and forth.
[0016]
A gear is formed on the outer peripheral portion of each tie bar nut 26 and is simultaneously driven to rotate by a mold thickness adjusting motor (not shown) provided on the end housing 3. The end housing 3 can be moved back and forth by a wheel provided at a lower portion thereof.
[0017]
As described above, the end portion on the end housing side of the tie bar 4 is supported at two places, that is, the support portion 22 provided at the front end portion of the end housing 3 and the spacer 23 provided at the rear end portion. The end housing 3 does not fall down due to the reaction force during the opening / closing operation of the mold clamping device and the biased injection pressure acting on the cavity surface.
[0018]
Further, since the screw portion of the tie bar 4 is the trapezoidal screw 24, the tie bar 4 can be securely held by the end housing 3 via the spacer 23. Furthermore, since the area in contact with the spacer 23 is larger than that of the triangular screw, the mutual contact surface pressure can be reduced, and fatigue of the spacer 23 and the trapezoidal screw 24 can be suppressed and durability can be increased. Further, the thickness of the spacer 23 can be reduced.
[0019]
Further, since the spacer 23 is a separate piece, it is possible to adopt parts made of different materials and to easily replace them. In the embodiment described above, the screw portion of the tie bar 4 is the trapezoidal screw 24, but it may be a square screw.
[0020]
【The invention's effect】
Since the present invention is configured as described above, the end housing collapses due to the reaction force during the opening / closing operation of the mold clamping device of the injection molding machine and the uneven injection pressure acting on the cavity surface, and the tie bar is bent. In this way, the mold can be protected and the parting surface of the mold can be uniformly opened during molding.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a fall prevention device for a mold clamping device according to the present invention.
FIG. 2 is an overall configuration diagram of a double toggle type mold clamping device.
FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2;
[Explanation of symbols]
3 End housing 4 Tie bar 21 Through hole 22 Support part 23 Spacer 24 Trapezoidal screw 25 Adjustment body 26 Tie bar nut

Claims (1)

The front end of the through hole (21) of the end housing (3) into which the end of the tie bar (4) is inserted is formed with a support portion (22) having a small diameter and supporting the tie bar (4). A spacer (23) having a cylindrical inner peripheral surface for supporting the outer peripheral surface of the threaded portion of the tie bar (4) is provided at the rear end of the through hole (21), and the tie bar (4) The screw portion of the end housing (3) is screwed with the trapezoidal screw (24) of the tie bar (4) and is not movable in the axial direction. (26) preventing device fall in the mold clamping device in an injection molding machine you characterized in that is provided.

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