JP3783214B2 - Clamping device tie bar and clamping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tie bar of a mold clamping device such as an injection molding machine, and a vertical or horizontal mold clamping device configured by connecting a pressure receiving plate and a fixed die plate by the tie bar.
[0002]
[Prior art]
Conventionally, the clockwise moment generated when the tie bars are fastened and fixed to the four corners of the fixed die plate is offset by the adjacent ones along the peripheral edge of the fixed die plate as different fastening rotation directions. The torsional deformation of the die plate is suppressed to facilitate the parallelism of the fixed plate (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent No. 3179019 (page 2-3, FIG. 2).
[0004]
[Problems to be solved by the invention]
In a normal tie bar, the screw shafts at both ends of the shaft are right-handed screws, and the tightening directions of the clamp nuts at both ends are different from each other. As a result, when one end is fastened and fixed to the pressure receiving plate and the other end is fastened to the fixed die plate, a clockwise rotational moment acts on the tie bar shaft and the fixed die plate, and twisting deformation occurs in both of them. It becomes like this.
[0005]
The rotational moment with respect to the fixed die plate is such that the screw shaft at both ends of the shaft adopts a right-handed tie bar and the screw shaft uses a left-handed tie bar. The tie bar adjacent to the tie bar can be controlled by changing the direction of fastening rotation by changing it to a right-hand screw and a left-hand screw alternately. The twist of a typical tie bar has not been solved yet.
[0006]
In the tie bar having this twist, the mold clamping force received through the fixed die plate tries to return to the state before twisting each time. In particular, in the vertical mold clamping device in which the fixed die plate is supported by the tie bar, unlike the horizontal mold clamping device, there is no other support for the fixed die plate. Due to the effect of twisting back, misalignment is likely to occur between the mold attached to the fixed die plate and the mold on the movable plate side. Repeated operation accuracy is impaired and maintenance is required. Although the tie bar twisting amount can be known from the clamping nut tightening amount, the twisting return amount differs depending on the clamping force, so it is difficult to grasp, and the die misalignment can be prevented by controlling the twisting return amount. I can't.
[0007]
The present invention has been conceived in order to solve the above-described conventional problems, and its object is to suppress the twisting of the tie bar shaft caused by tightening of the clamp nut by making the tightening direction of the clamp nut relative to the tie bar the same. In addition, another object of the present invention is to provide a new mold clamping device tie bar and a mold clamping device using the tie bar that can suppress twisting of the fixed die plate when the tie bar is fastened and fixed.
[0008]
[Means for Solving the Problems]
The tie bar of the present invention according to the above object is a tie bar of a mold clamping device in which a pressure receiving plate and a fixed die plate are connected at a corner, and a movable plate between the plates is movably inserted into and supported by the fixed die plate. The screw directions of the screw shafts at both ends of the shaft are different between the left screw and the right screw, and the tightening directions of the clamp nuts of both screw shafts are configured in the same direction.
[0009]
The tie bar of the present invention is a tie bar of a mold clamping device in which a pressure receiving plate and a fixed die plate are connected at a corner, and a movable plate between the plates is movably inserted into and supported by the fixed die plate. The right screw tie bar is formed with a right screw thread at one end and a left screw screw at the other end, and the tightening direction of the clamp nuts at both ends of the shaft is the same as the right direction. The other end of the left screw is formed as a right screw, and consists of a left tightening tie bar in which the tightening directions of the clamp nuts at both ends of the shaft are the same in the left direction, and both are used for connecting the plates. Is.
[0010]
The mold clamping device according to the present invention is a vertical mold clamping device in which a pressure receiving plate installed on a machine base by the tie bar and a fixed plate above the pressure receiving plate are connected to each other, and is mounted on the machine base by the tie bar. This is a horizontal mold clamping device in which a pressure receiving plate and a fixed plate that are provided to each other are connected.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1A shows a right-tightening tie bar 10 and FIG. 1B shows a left-tightening tie bar 20.
The right tightening tie bar 10 has screw shafts 11 and 12 at both ends of the shaft, a screw shaft 11 at one end is a right screw, and a screw shaft 12 at the other end is a left screw. Both are set to be the same as the right direction.
[0012]
The left-tightening tie bar 20 has screw shafts 21 and 22 at both ends of the shaft, a screw shaft 21 at one end is formed as a left screw, and a screw shaft 22 at the other end is formed as a right-hand screw. Both are set to be the same as the left direction.
The axial grooves at both ends of the shaft are the key grooves 14 and 24, and the lateral grooves are the annular grooves 15 and 25 of the retaining ring.
[0013]
FIG. 2 shows a vertical mold clamping apparatus. A pressure receiving plate 2 installed on the upper surface of the machine base 1 and a fixed die plate 3 thereabove are connected to both the right clamping tie bar 10 and the left clamping tie bar 20. The movable plate 4 is inserted into and supported by the tie bars 10 and 20 so as to be movable up and down, and the movable plate 4 is connected to the ram 6 of the mold clamping cylinder 5 below the pressure receiving plate.
[0014]
Further, on the upper part of the fixed die plate 3, an injection device 7 is provided on a pair of guide shafts 8 and 8 standing on the fixed die plate so as to be able to move up and down, although not shown in the drawing, and is provided downward. From the nozzle of the apparatus 7, the molten resin can be injected and filled into the mold 9 that is divided and attached to the fixed die plate 3 and the movable plate 4.
[0015]
In this saddle type mold clamping device, the right receiving tie bar 10 and the left clamping tie bar 20 are used as one set for connecting the pressure receiving plate 2 and the fixed die plate 3, and the two sets are used on the operation side (the lower side in FIG. 3). ), The right side is connected by a right-tightening tie bar 10, and the left side is connected by a left-tightening tie bar 20. The clamp nuts 13 and 23 screwed to the screw shafts 12 and 22 are tightened toward the center of the plate using a nut rotating jig (not shown), thereby unifying the tie bar clearance.
[0016]
Further, as shown in FIG. 4, key grooves 14a and 15a corresponding to the key grooves 14 and 24 provided at both ends of the shaft are provided in the tie bar insertion holes 2a and 3a of the pressure receiving plate 2 and the fixed plate 3 from the inner surface of the plate. Keys 16 and 26, which are formed along the surface and fitted in the key grooves 14a and 15a on the tie bar side, are fitted in the key grooves 14a and 15a, and the tie bars 10 and 20 are respectively inserted into the tie bar insertion holes 2a and 3a. When inserted, the keys 16 and 26 stop the rotation of the tie bar when the nut is tightened, and also prevent the tightening torque from loosening.
[0017]
In the right tightening tie bar 10 and the left tightening tie bar 20, the screw directions of the screw shafts 11, 12, 21, 22 at both ends are different from each other. The tightening direction of the clamp nuts 13 and 23 is different from the right direction at both ends of the right tightening tie bar 10 and from the left direction at both ends of the left tightening tie bar 20. However, in both cases, since the rotational moments at both ends with respect to the tie bar shaft are in the same direction, the tightening force does not act as a twisting force of the tie bar shaft, and the tie bar shaft is not twisted by the tightening force. Even if the rotational moment is in the same direction, the nuts can be easily tightened by the keys 16 and 26 that prevent the tie bar from rotating.
[0018]
In addition, the tightening direction of the clamp nuts 13 and 23 with respect to the lower surface of the pressure receiving plate and the upper surface of the fixed die plate is different from the right direction on the right side of the plate and the left direction on the left side of the plate. Thus, the occurrence of torsional deformation due to the rotational moment of the fixed die plate 3 is suppressed.
[0019]
Due to the synergistic effect of the suppression of twisting in the fixed die plate 3 and the suppression of twisting of the tie bar shaft, the parallelism of the fixed die plate 3 which has been difficult until now due to the effect of twisting can be easily obtained. In addition, since twisting at the assembly stage is prevented, even a vertical mold clamping device has a structure that does not have mechanical twisting, and twisting return deformation due to mold clamping pressure does not occur. Since the core 9 between the mold 9 attached to the pressure receiving plate 2 and the mold 9 attached to the movable plate 4 is maintained for a long time, the precision molding required for injection molding of an optical pickup lens, a narrow pitch connector and the like is eliminated. The condition, especially the precision of the repetitive operation of a mold made with high accuracy, is further improved, the maintenance cost is reduced, and molding defects due to misalignment are eliminated.
[0020]
In the above embodiment, the right-tightening tie bar 10 and the left-tightening tie bar 20 are arranged separately on the right side and the left side, but they may be arranged separately on the front side and the rear side, and the same tie bars may be arranged diagonally. You may arrange | position in the corner part. In either case, the same effects as those of the above embodiment are achieved.
[0021]
FIG. 5 shows a case where the connection is performed using only the right tightening tie bar 10, and the tightening direction of the clamp nut 13 with respect to the lower surface of the pressure receiving plate 2 and the upper surface of the fixed die plate 3 is the same direction. Although there is no cancellation of the rotational moment with respect to the die plate 3, the rotational moments at both ends with respect to the tie bar shaft are in the same direction as the clamp nut 13, so that the tightening force does not act as a torsional force of the tie bar shaft. The twist of the shaft is suppressed. Therefore, since the tie bar shaft does not twist and return due to the clamping force, it can be used in a vertical mold clamping device that injection-molds ordinary molded products to maintain long assembly accuracy. It becomes possible.
[0022]
FIG. 6 shows a horizontal mold clamping device, in which a pressure receiving plate 32 and a fixed die plate 33 erected on the upper surface of the machine base 31 are connected to both the right clamping tie bar 10 and the left clamping tie bar 20. The movable plate 34 is inserted into and supported by the tie bars 10 and 20 so as to be able to advance and retreat, and the movable plate 34 is connected to the ram 36 of the clamping cylinder 35 at the center of the pressure receiving plate.
[0023]
Although not shown in the drawing, an injection device is provided outside the fixed die plate 33 so as to be able to advance and retreat. The injection device nozzle is divided into a fixed die plate 33 and a movable plate 34. The mold 39 attached in this way can be injected and filled with molten resin.
[0024]
In this horizontal mold clamping apparatus, as in the case of the vertical mold clamping apparatus shown in FIG. 2, the twisting of the pressure receiving plate 32 and the fixed die plate 33 is suppressed, and the twist of the tie bar shaft is also suppressed. Since twisting in the case is also prevented, the structure does not have mechanical twisting. [0025]
As a result, twisting and return deformation due to mold clamping force does not occur, so that the accuracy during assembly is kept long, and there is no misalignment of the mold 39 attached to the fixed die plate 33 and the movable plate 34. It can be used as a mold clamping device.
[0026]
Further, by using either the right-clamping tie bar 10 or the left-clamping tie bar 20, it is also possible to assemble a horizontal mold clamping apparatus that is normally employed for injection molding of a molded product into a mold clamping apparatus that does not twist the tie bar shaft. .
[Brief description of the drawings]
FIG. 1 is a side view of a tie bar according to the present invention.
FIG. 2 is a longitudinal sectional front view of an essential part of a vertical mold clamping device assembled using both a right-tightening tie bar and a left-tightening tie bar according to the present invention.
FIG. 3 is a plan view of the same.
FIG. 4 is a plan sectional view of four corners of a fixed plate.
FIG. 5 is a plan view of a vertical mold clamping device assembled using the right clamping tie bar of the present invention.
FIG. 6 is a longitudinal sectional front view of a main part of a horizontal mold clamping apparatus assembled by using both the right clamp tie bar and the left clamp tie bar of the present invention.
[Explanation of symbols]
1,31 Machine base 2,32 Pressure receiving plate 3,33 Fixed die plate 4,34 Movable plate 5,35 Mold clamping cylinder 7 Injection device 9,39 Mold 10 Right clamping tie bar 11,12 Screw shaft 13 Clamp nut 14,14a , 24, 24a Keyway 16, 26 Key 20 Left-tightening tie bars 21, 22 Screw shaft 23 Clamp nut

Claims (4)

A tie bar of a mold clamping device that connects a pressure receiving plate and a fixed die plate at a corner and supports a movable plate between the plates so as to be movably inserted into the fixed die plate.
A tie bar of a mold clamping device, wherein the screw directions of screw shafts at both ends of the shaft are different from those of a left screw and a right screw, and the clamping directions of clamp nuts of both screw shafts are configured in the same direction. A tie bar of a mold clamping device that connects a pressure receiving plate and a fixed die plate at a corner and supports a movable plate between the plates so as to be movably inserted into the fixed die plate.
A right-tightening tie bar in which the screw shafts at both ends of the shaft are formed with one end being a right-hand thread and the other being a left-hand thread so that the tightening directions of the clamp nuts at both ends of the shaft are the same in the right direction;
The screw shaft at both ends of the shaft consists of a left-tightening tie bar in which one end is a left-handed screw and the other end is a right-handed screw so that the tightening direction of the clamp nut on both ends of the shaft is the same in the left direction.
A tie bar for a mold clamping device, wherein both of them are used for connecting the plates. A saddle type mold clamping device comprising: a pressure receiving plate installed on a machine base and a fixed die plate above the pressure receiving plate connected by the tie bar according to claim 1. A horizontal mold clamping apparatus comprising a pressure receiving plate and a fixed die plate connected to each other on a machine base by the tie bar according to claim 1 or 2.

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