JPH04201428A - Molded item-discharging apparatus for resin molding machine - Google Patents

Abstract

PURPOSE:To actuate smoothly an ejector plate and to prevent it from deviation of positioning even if mold plates are thermally expanded by providing a long channel on the mold plate forming a cavity in the thermally expanding direction of the mold plate, mounting slidably one end of a guide pin guiding the ejector plate and providing three or more of the guide pins. CONSTITUTION:A guide pin 11 is inserted through an ejector plate 12 on which an ejector pin 14 and a return pin are fixed and guides the plate 12 and one end thereof 11a is fixed in a perforated hole 15 formed on a fixing plate of the movable side. On a movable mold plate 6, a long channel 21 to which another end part 11b of the guide pin 11 is slidably fitted is formed in such a way that the long axis is along the thermally expanding direction of the movable mold plate 6. At least three or more guide pins are provided and when four guide pins are provided, it is pref. that the long axis of each long channel 21 faces to the center of the movable mold plate 6. Even if the movable mold plate 6 is expanded by injecting a molten resin, the guide pins are not influenced by the thermal expansion and as three or more guide pins are provided, there is no possibility of deviation of positioning of the ejector plate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a molded product discharge device of a resin molding machine.
In particular, the extrusion plate (ejector plate) of the molded product ejection device can be operated smoothly even when the mold plate forming the cavity is thermally expanded.

(Prior Art) Automotive parts include resin molded products such as instrument panels, meter housings, console boxes, front grills, wheel covers, and bumpers. The molding method used to mold these materials depends on the type and physical properties of the resin used, productivity,
There are many methods depending on economic efficiency, such as injection molding, compression molding, extrusion molding, foam molding, and reaction injection molding.

In particular, injection molding is widely used for molding automobile parts because even complex shapes can be obtained in a single molding process. This injection molding is a method in which a molding material is plasticized in a heated cylinder, press-fitted into a cavity in a mold by applying high pressure, the material is cooled and solidified, and then taken out as a molded product.

The main parts of the injection mold are as shown in Figure 5.
It consists of a fixed mold 1 and a movable mold 2 that is movable forward and backward relative to the fixed mold 1. The fixed mold 1 has a fixed mold plate 3 attached to a fixed mounting plate (not shown). The movable mold 2 also has a movable mold plate 6 attached to the movable mounting plate 4 via a spacer 5, and between the movable mold plate 6 and the fixed mold plate 3. A cavity 7 is formed corresponding to the external shape of the molded product. The fixed side template 3 includes:
A sprue 8 is formed which communicates with the cavity 7 via a runner and a gate (none of which are shown), and through this sprue 8, the molten resin material is transferred from a nozzle 9 of an injection device (not shown) to the cavity 7. It is designed to be ejected inside.

The mold 2 on the movable side is provided with a molded product discharging device 10 for taking out the molded product from the movable mold plate 6. This molded product ejecting device 10 includes an ejector plate 12 that moves while being guided by a guide pin 11 provided on a movable mold 2.
have. The guide pin 11 is provided to pass through the ejector plate 12, and has both ends 11a,
11b is fixed to the movable side mounting plate 4 and the movable side template plate 6, respectively. The ejector plate 12 consists of a first plate 12a and a second plate 12b, and a guide bush 13 that makes sliding contact with the guide pin 11 is attached to the first plate 12a.

The ejector plate 12 also includes an ejector pin 14 for pushing the molded product from the movable mold plate 6, and when closing both molds 1.2, the ejector plate 12 is pushed back to move the ejector pin 14 from the cavity surface 7a. A return pin (not shown) for retraction is attached. Further, when both molds 1.2 are opened and the movable mold 2 is retreated to near the retraction limit, an ejector rod is provided which prevents only the backward movement of the ejector plate 12 and causes the ejector pin 14 to protrude from the cavity surface 7a. (not shown) is fixed to the molding machine. In place of this ejector rod, a hydraulic cylinder for extruding the ejector plate 12 is incorporated into the molded product discharging device 10, and the molding machine is configured to drive the hydraulic cylinder at an appropriate timing regardless of the movement of the movable mold 2. There is also.

The molded product discharging device 10 configured as described above operates as follows.

When the injection of the molten resin material and the cooling and solidification within the cavity 7 are completed, both molds 1.2 are first opened, and the movable mold 2 is moved backward. When the mold 2 on the movable side retreats to near the retreat limit, only the ejector plate 12 is prevented from retreating by the ejector rod, so the guide bush 1
3 slides along the guide pin 11, each time the ejector plate 12 moves forward relative to the movable mold plate 6. As a result, the ejector pin 14 protrudes from the cavity surface 7a, and the molded product is ejected from the movable mold plate 6.

On the other hand, when entering the mold clamping process, the movable mold 2 moves forward toward the fixed mold 1. Then, when the tip of the return pin hits the surface of the stationary mold plate 3 just before both molds 1.2 are closed, the ejector plate 12 is pushed back and the ejector pin 14 retreats to the cavity surface 7a.

(Problems to be Solved by the Invention) When performing injection molding, as shown in FIG. thermally expands in the direction shown by arrow B in the figure.

As a result, the guide pin 11 is displaced from its original axial position by the amount of thermal expansion indicated by C in the figure.

If such a positional shift of the guide pin 11 occurs, as shown in FIG.
The sliding movement between the guide pin 11 and the ejector plate 12 will not be smooth, and the ejector plate 12 will malfunction, causing the molded product ejecting device 10
There was a problem that the device could not perform its intended function.

In addition, when there are two guide pins 11, the ejector plate 12 may be affected by its own weight or external force.
There was also a possibility that positional deviation would occur in 2.

The present invention has been made in order to solve the problems associated with the above-mentioned prior art, and is a molded product ejecting device incorporated into a resin molding machine, which allows the ejector plate to operate smoothly even when the template is thermally expanded. Another object of the present invention is to provide a molded product ejecting device for a resin molding machine that prevents displacement of an ejector plate.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes at least two molds each having a mold plate that forms a cavity attached thereto, and molding a molded product made of a resin material within the cavity. installed in a resin molding machine, and one of the molds is provided with an ejector plate attached with an ejector bin for ejecting the molded product from the cavity, so as to be movable forward and backward relative to the mold plate; A molded product ejecting device in which one end of a guide pin that is inserted through the ejector plate and guides the ejector plate is attached to the mold plate, the molded product ejecting device having at least three guide pins, and having at least three or more guide pins, A molded product discharging device for a resin molding machine is characterized in that a long groove extending along the template is formed in the template, and one end of each guide pin is slidably attached to the long groove.

(Function) When the ejector plate moves forward relative to the template while being guided by the guide pin, the ejector pin protrudes from the cavity and the molded product is ejected.

Even if the template expands thermally during resin molding, one end of each guide pin slides within the long groove, so the position of the guide pin will not shift, and the ejector plate will move forward smoothly. Become.

Furthermore, since at least three guide pins are attached, the position of the ejector plate itself will not shift.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a sectional view showing an injection mold according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIGS. The same reference numerals are given to the same members as those shown, and some explanations thereof will be omitted.

The injection mold shown in the figure is composed of a fixed mold 1 and a movable mold 2 that is movable forward and backward relative to the fixed mold 1. side mold 2
is provided with a molded product discharging device 20 for taking out the molded product from the movable mold plate 6.

This molded product ejection device 20, like the conventional one, includes an ejector plate 12 to which an ejector bin 14 and a return pin (not shown) are attached, and is inserted through the ejector plate 12 to guide the ejector plate 12. It has a guide pin 11. One end 11a of this guide pin 11 forms a through hole 1 in the movable mounting plate 4.
It is also fixed at 5 as in the past.

However, the other end 11b of the guide pin 11 in this embodiment is slidably attached to the movable mold plate 6. That is, as shown in FIG. 2, the movable template 6 is formed with a long groove 21 into which the end 11b of the guide pin 11 is fitted.
On the other hand, the end portion 11b of the guide pin 11 has the long groove 21.
A flat surface 23 is formed which makes sliding contact with the side wall 22 of. Moreover, the long axis of the long groove 21 is formed along the direction of thermal expansion of the movable mold plate 6, and its length is set to be greater than the amount of thermal expansion of the movable mold plate 6.

Further, in this embodiment, at least three or more guide pins 11 are provided. In particular, as shown in FIG. 3, in the case of the molded product discharging device 20 provided with four guide pins 11, the long axis 21a of each long groove 21 should be formed so as to face the center O of the movable template 6. good.

Next, the operation of this embodiment will be explained.

When injection molding is performed, as shown in FIG.
The heat of the high-temperature molten resin material is conducted, and the arrow B in the figure
Thermal expansion occurs in the direction shown by . When the movable template 6 thermally expands in this way, both ends 11a and llb of the guide pin 11
Of these, the end portion 11b on the side attached to the movable template plate 6 slides along the long groove 21, so that the guide pin 1
1 is not affected by thermal expansion and does not shift from its original axis position.

Therefore, when the ejector plate 12 moves forward relative to the movable mold plate 6 as shown by the imaginary line, the smooth sliding between the guide bush 13 and the guide pin 11 is not hindered, and the ejector plate 12 moves forward relative to the movable template 6. Malfunctions of the plate 12 no longer occur.

Further, since at least three guide pins 11 are provided, the ejector plate 12 will not wobble along the direction perpendicular to the guide pins 11, and there is no possibility that the ejector plate 12 will be displaced due to its own weight or external force.

Although the above-described embodiments illustrate the case where the present invention is applied to an injection molding machine, the present invention is not limited to this case, and can be applied to a molding machine that employs other molding methods such as compression molding. It is something that can be applied.

(Effects of the Invention) As explained above, according to the molded product discharging device of the resin molding machine of the present invention, long grooves extending along the direction of thermal expansion of the template are formed in the template, and 20 long grooves are formed in the template. Since one end of the guide pin is slidably attached to the mold plate, the position of the guide pin will not shift even if the template expands thermally, and the ejector plate can smoothly move forward and backward.

Further, since there are at least three guide pins, it is possible to prevent the ejector plate from shifting its position.

[Brief explanation of the drawing]

1 is a cross-sectional view showing an injection mold incorporating a molded product discharging device according to an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1; 3 is a cross-sectional view of a main part showing an example of the arrangement of long grooves formed in the movable template, FIG. 4 is a cross-sectional view of a main part for explaining the present invention in detail, and FIG.
The figure is a cross-sectional view showing an injection mold incorporating a molded product ejecting device such as a boat, and Figure 6.7 is a cross-sectional view of a main part used to explain the operation of the conventional example shown in Figure 5. be. 1... Fixed side mold (mold), 2... Movable side mold (mold), 3... Fixed side template (template), 6... Movable side template ( template), 7... Cavity, 11... Guide pin,
DESCRIPTION OF SYMBOLS 12... Ejector plate, 14... Ejector pin, 20... Molded product discharge device, 21... Long groove, 23... Flat surface. Patent applicant Nissan Motor Co., Ltd. agent Patent attorney 8 1) Mikio (and 1 other person) Figure II5

Claims (1)

[Claims] A mold plate forming a cavity is attached to each of at least two molds, and the resin molding machine molds a molded product made of resin material within the cavity. An ejector plate to which an ejector pin for ejecting the product from the cavity is attached is provided so as to be movable relative to the mold plate, and one end of a guide pin inserted through the ejector plate and guiding the ejector plate is attached to the mold plate. In the molded product discharging device, which has at least three guide pins, a long groove extending along the direction of thermal expansion of the template is formed in the template, and each of the guide pins is attached to the long groove. A molded product discharge device for a resin molding machine, characterized in that one end of the molded product is slidably attached.