JPS61244517A - Undercut treatment device of mold - Google Patents

Abstract

PURPOSE:To contrive miniaturization of a cylinder by performing forward and backward movements of an undercut pin by low input hydraulic pressure or air pressure, by building a toggle and cam mechanisms in a hydraulic cylinder so as to enable to bear high injection pressure. CONSTITUTION:When an outer cylinder 21 of a piston of a hydraulic cylinder 1 has turned into a state of the bottom dead center, the tip part 3a of an undercut pin 3 is suspended by protruding the same. In this instance, molding is performed by applying a signal for filling a core part 38 of a mold with a molding material to the core part 38. Hydraulic pressure is sent into a hydraulic pressure chamber 25 through a hydraulic pressure supply hole 42 and the external cylinder 21 of the piston is shifted in the direction of an arrow R. In this instance, a cum groove 29 in the inside of an extension part 21 is shifted also along with the external cylinder 21 of the piston and a toggle mechanism 17 is begun to close. As the toggle mechanism 17 is closed, the undercut pin 3 is restored to the original position by shifting the shaft 18 in the direction of the arrow S and a molded article 38 is unloaded. As force is applied to the undercut part by opening or closing the built-in toggle mechanism, even if high injection pressure is applied to the mold, the mold can bears the force sufficiently and the cylinder itself can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a finishing/darcut processing mechanism in a mold, and in particular, it is capable of holding an undercut pin against large injection pressure with a small driving force, and is compact. This invention relates to an undercut processing device for molds that enables flexible designs.

(Prior Art) Hydraulic cylinders and slide cores have conventionally been used as undercut treatment devices for molds.

However, these devices have limitations on the adjacent pitch due to their dimensional structure, when the undercarts are close to each other in a narrow part of the mold, or when the undercut processing must be performed independently for each of the undercarts due to different punching directions. Ta.

In order to solve this problem, a hydraulic cylinder 51 shown in FIG.
This has been dealt with by changing the direction of the movement using a cam mechanism 52 or the like.

(Problems to be Solved by the Invention) However, in such a conventional undercut processing device, in order to take measures such as adding a cam mechanism,
The large number of parts caused gullies and increased mold costs.

Furthermore, even in the case of a single undercar/) process, the hydraulic cylinder used as the drive source has a large outer diameter, so a large mounting hole must be drilled in the insert, which is the center of the mold. However, a problem arose in that the processing period for the insert became longer and the strength of the insert decreased.

Therefore, in order to solve the above-mentioned problems, the present invention incorporates a toggle and cam mechanism into a hydraulic cylinder so as to withstand high injection pressure, so that the undercut pin can be moved forward and backward using low input hydraulic pressure or air pressure. It is an object of the present invention to provide an undercut processing device which is capable of reducing the size of the cylinder.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a toggle mechanism that constitutes a toggle mechanism on the distal end side of a fixed rod provided in a cylinder device fixed to a mold. At the same time, the other toggle link is attached to a shaft for advancing and retracting the undercut provided in the mold, and a piston that can freely engage the toggle link is installed in the toggle device. It is characterized by an interior that can be moved freely.

(Function) Since the present invention has the above configuration, when hydraulic pressure or compressed air is sent into the space defined by the fixed port/nod and the piston outer cylinder in the cylinder device fixed to the mold, the cylinder device is fixed. The piston outer cylinder moves forward relative to the cylinder.

As a result, the cam inside the piston outer cylinder presses the toggle mechanism in the direction to open it, thereby advancing the shaft connected to the toggle mechanism. When the shaft moves forward, the under force/throat pin is pressed and moved to a predetermined position, forming an ungut cut in the mold.

In this state, even if a high injection pressure is applied within the mold, the undercut pin is not pushed back by the force-increasing action of the toggle mechanism, and the low-pressure driving source can sufficiently resist the injection pressure.

Further, in contrast to the above action, when hydraulic pressure or compressed air is fed to move the piston outer cylinder backward with respect to the fixed rod, the toggle mechanism is moved in the closing direction by the cam of the biston outer cylinder. During this process, the undercut part recedes through the shirt collar.

The molded product can be removed. In this case, it is sufficient to overcome the pulling force from the molded product, but in this case as well, the undercut pin can be retracted with a small driving force using the toggle mechanism.

In this way, it is possible to operate the cut section successfully using a cylinder with low pressure and low driving force.

Therefore, it is possible to provide an apparatus that performs undercut processing in narrow adjacent pitch portions without providing any special external equipment other than the hydraulic cylinder, and by downsizing the hydraulic cylinder itself.

(Example) Embodiments of the present invention will be described based on the drawings.

In FIGS. 1 and 2, in the hydraulic cylinder in the device of the present invention, 1Fi is installed in the mounting hole 4 coaxially with the undercut pin 6 in the fixed side 2a of the mold 2. A boss 7 protruding from the flange part 6 of 5 is inserted and forms a trap to fix the flange part 6 to the mold with two bolts 8.8.

Inside the hydraulic cylinder 1, a fixed rod 9 is integrally formed with the cylinder 5 and projects from the rear end (upper end side in the figure) of the cylinder 5 along the central axis.

At the rear end of the fixed rod 9, two boat trolleys 10, 11 are provided for supplying hydraulic fluid into the cylinder 5.

Furthermore, the fixed rod 9 has a large diameter portion 9a in its center,
A rotating shaft 12 is provided on the tip side thereof, and a toggle link 13. A toggle 9m17 is attached which connects the i4 with the rotating shaft 15 and 1/i, respectively. Toggle machine 1
The structure 17 glue/guts 4 is connected to the shaft 18 by the rotating shaft 16.
The shaft 18 is connected to a play connection head 19,
It is connected to the undercut pin 6 by a connecting neck 20.

In the space between the fixed rod 9 and the cylinder 5, the fixed rod 9
A piston outer cylinder 21 that moves inside the 7 cylinder 5 as an outer cylinder.
is provided.

The piston outer cylinder 21 is assembled and integrated from a plurality of blocks, and its outer periphery partially contacts the inner periphery of the cylinder 5, further forming a dog 22 in the center. This dog 22 is used to press the position detection limit switches 23 and 24 by finger movement of the piston outer cylinder 21 and determine the finger stroke.

Further, a space defined by the inner periphery of the piston outer cylinder 21 and the outer periphery of the fixed rod 9 is provided, and this space is separated by the hydraulic chamber 25 separated by the large diameter portion 9a of the fixed rod 90.
．． It is 26.

Furthermore, an extension portion 21a as a tip portion of the piston outer cylinder 21
Inside, a roller 27 is coaxially provided on the outside of the rotating shaft 15, and cam grooves 28 and 29 are provided to restrict the movement of the roller 27.
is formed by making the inner periphery of the piston/outer cylinder 21 eccentric.

Here, 30, 31.32 is 01J for hydraulic seal
/g, 33, 34. 55 is a relief hole for compressed air accompanying the movement of each biston, 66 is a keyway for preventing rotation of the undercut pin 5, and 67 is a rotation prevention pin.

Next, the operation of the underforce/softening processing apparatus of the present invention will be explained.

In the state shown in FIG. 1, when hydraulic pressure is supplied to the hydraulic supply boat 10, the hydraulic oil passes through the curved rod 41 and enters the hydraulic chamber 26. As a result, the piston outer cylinder 21 is pushed out in the direction of arrow P in the figure. Since the cam groove 28 in the extension part 21a moves together with the piston outer cylinder 21, the roller 27 provided in the toggle mechanism 17 is pushed diagonally downward to the right in the figure, and the toggle mechanism 17 begins to open.

Due to the extension of the toggle mechanism 17, the shaft 18Fi moves in the direction of arrow Q, and the under force pushes out the throat pin 3.

Therefore, when the piston outer cylinder 21 of the hydraulic cylinder 1 reaches the bottom dead center, that is, as shown in FIG. 2, the tip 6a of the undercut bin 3 protrudes and stops. At this time, the tongs 22 push down the limit switch 24, so it can be confirmed that the tip 6a of the pin 3 is protruding, and a signal is output to fill the molding material into the core part 38 of the mold (2). When the molding material is solidified and ready to be taken out from the mold, hydraulic pressure is supplied from the boat 11 and fed into the hydraulic chamber 25 through the hydraulic supply hole 42.This causes the piston 7 to The outer cylinder 21 is moved in the direction of the arrow in the figure.At this time, the cam groove 29 in the extension part 2Ia also moves together with the piston outer cylinder 21, so the toggle a mechanism 1
7, the roller 27 is pushed diagonally upward to the left in the figure, and the toggle mechanism 17 begins to close.

By closing the toggle mechanism 17, the shaft 18 moves in the direction of arrow S, the undercut bin 6 returns to its original position, the moving side 2b of the mold is opened, and the molded product 38 can be taken out.

In this embodiment, the cylinder is driven by hydraulic pressure, but the present invention is not limited to this, and other methods such as pneumatic pressure may be used.

When pneumatic sealing is used, there is no need for oil leakage or air bleeding every time the mold is installed, and the time required to install the mold to the molding machine can be significantly reduced.

Furthermore, as shown in FIG. 5 (conventional example) and FIG. 6 (this example), when the compact toggle a structure of the present invention is incorporated, the outer diameter width D2 of the device using the hydraulic cylinder etc. is smaller than that of the conventional example. Since it is extremely small compared to the outer diameter width of P, its adjacent pitch P2 is also P.

can be made smaller compared to

(Effects of the Invention) As is clear from the above explanation, the present invention opens and closes a toggle mechanism built in a piston outer cylinder that can be moved by low-pressure driving force and applies that force to the undercut portion. Even if high injection pressure is applied to the mold, it can withstand the force sufficiently.

As a result, the cylinder itself can be made smaller, and low-pressure driving force can be used. In addition, the adjacent pitch can be made smaller when cutting in different directions, increasing the degree of freedom in designing molded products. .

In addition, since the toggle cam mechanism is built-in, there is no need to add any other external equipment, so there is no need for troublesome processing on the mold, which shortens the mold production period and reduces costs. Moreover, the strength and rigidity of the mold can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the top dead center state of a hydraulic cylinder in an apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the bottom dead center state of the hydraulic cylinder in FIG. 1, Fig. 6 is a perspective view of a hydraulic piston rod with a toggle of the device shown in Fig. 1, Fig. 4 is an explanatory diagram of the case where a conventional hydraulic cylinder is used to perform undercut/throat processing, and Fig. 5 is a diagram of the conventional example. A diagram showing the limit of adjacent pitch in the device. FIG. 6 is a diagram showing that the limit of adjacent pitch in the device of this actual weaving example has been improved. 1... Hydraulic cylinder 2... Mold 3... Undercut pin 9... Fixed rod 18... Shaft 21... Piston outer cylinder patent applicant Toyota Motor Corporation (and 1 other person)

Claims (1)

[Claims] (1) One of the toggle links constituting the toggle mechanism is attached to the tip side of a fixed rod provided in a cylinder device that is fixed to the mold, and the other toggle link is attached to an undercut provided in the mold. An undercut treatment device for a mold, characterized in that a pin is attached to a shaft that moves forward and backward, and a piston that can be freely engaged with the toggle link is movably housed in the cylinder device.