JPH0357461Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention uses a combination of a large oil cylinder, a large piston, a small oil cylinder, and a small piston, thereby creating a twin oil cylinder and twin piston that can improve the precision of plastic products. This relates to a plastic injection molding machine.

[Prior art and its problems]

The commonly used single oil cylinder, single piston plastic injection molding machine is
One piston is provided in one oil cylinder, which has the following disadvantages.

(1) Injection problems: If the diameter of the piston is relatively small, it can be injected at high speed, but the plastic product is prone to collapse and deformation due to insufficient pressure. Alternatively, if a piston with a relatively large diameter is used, the pressure during injection can be increased, but the injection speed is slow, so the weld lines of the plastic product are noticeable and the appearance is not beautiful, or it is difficult to mold. Therefore, the general single oil cylinder, single piston plastic injection molding machine can only achieve one type of efficiency with high speed or high pressure, but cannot satisfy the needs of manufacturing various types of products. . This need could be met by using a high-flow pump or a high-pressure pump, but this equipment is expensive and consumes a large amount of energy.
Not economical.

(2) Mold opening/closing problem: Since there is one toggle device, if the mold opening course is short, the amount of plastic injection is sufficient, but if the length of the product is relatively long, it will be difficult to remove it from the mold. First, relatively long products can only be manufactured after using a relatively large model, and not only is the cost of machinery and equipment high and consumes electricity, but the pressure points for pressing the mold when opening the mold are either vertically or horizontally. Not only is the product prone to bristles, but it also requires a relatively large amount of pressure and wastes electricity. A direct pressure type machine can widen the mold opening course to make it easier to take out the product, and has a relatively large mold pressing force, but it is not economical because it uses a single oil cylinder or a single piston.

(3) Injection metering problem: Since the replenishment of oil in the oil cylinder is controlled by one solenoid valve, the metering of plastic raw materials is slow and cannot be done accurately.

In view of the above drawbacks, the present invention provides a twin oil cylinder, twin piston plastic injection molding machine.

The main purpose of this invention is to use a small piston to quickly fill the mold space with plastic raw materials in the injection field, to help mold products with a large volume and relatively thin thickness, and to improve the surface area. In addition to improving the aesthetic appearance and production speed, the large piston applies pressure to avoid collapse of the product surface or deformation of large volume and relatively thin products, thereby increasing the precision of the product and making it possible to process products of all shapes and sizes. The purpose of the present invention is to provide a twin oil cylinder, twin piston plastic injection molding machine that can be applied to molding products.

The next main purpose of this invention is to open and close the mold by first using a small piston to open the mold at high speed, then using a large piston to strongly press the mold, and by moving the force point that presses the mold down to the center. It is possible to avoid hair edges on the product, the mold opens quickly and has a large course, it can improve the problem of not being able to take out the molded object from the mold, and it is a relatively small model with a relatively large shape. To provide a twin oil cylinder, twin piston plastic injection molding machine that can produce long products, thereby saving mechanical equipment and electricity costs and increasing economic profits.

Another purpose of this invention is that, in order to measure the amount of plastic injection, the large and small oil cylinders are all equipped with the same type of electromagnetic valve, and the compression force of the plastic is transferred to the piston rod via the hydraulic motor and hydraulic motor cover. The oil in the large oil cylinder flows from the oil hole through the electromagnetic valve to the other oil holes without resistance, and then to the large piston and then to the small piston via the piston rod. The oil in the small oil cylinder flows from the oil hole to the other oil hole without resistance through the electromagnetic valve and enters the left side of the small piston, and the total volume of oil in the large and small oil cylinders remains the same. Regardless of how the position of the piston moves, the amount of oil in the large and small oil cylinders remains constant, and both oil cylinders are equipped with electromagnetic valves, allowing the large and small pistons to move synchronously and metering quickly and accurately. We provide twin oil cylinder, twin piston plastic injection molding machines.

Another purpose of the present invention is to quickly fill the plastic raw material into the mold with a small piston and apply high pressure with the large piston, so that the surface of relatively thick products does not collapse or the plastic material is large in volume and compared to other products. To provide a twin oil cylinder, twin piston plastic injection molding machine that can avoid deformation of thin products, thereby increasing production speed, high precision, low manufacturing cost, and increasing economic profit. be.

[Means and actions for solving problems]

As shown in FIG. 1, the inner diameter of the large oil cylinder 1 is larger than the inner diameter of the small oil cylinder 3, a large piston 2 is provided in the large oil cylinder 1, and a small piston 4 is provided in the small oil cylinder 3. The diameter of the large piston 2 is also larger than the diameter of the small piston 4, and the large oil cylinder 1 and the small oil cylinder 3 are connected in the axial direction, and the piston rod 5 of the small piston 4 is also connected to the large piston 2 in the axial direction. Moreover, the spaces inside the large oil cylinder 1 and the small oil cylinder 3 do not communicate with each other.

Oil holes 6, 7, 8, 9 and 10, 1 in large oil cylinder 1 and small oil cylinder 3, respectively.
1, 12, and 13, one electromagnetic valve controls the flow of the oil passages of the oil holes 8, 9, and another electromagnetic valve controls the flow of the oil passages of the oil holes 12, 13. The electromagnetic valve is as shown in FIG.

As shown in FIG. 2, the piston rod 14 of the large piston 2 passes through the large oil cylinder 1, and the hydraulic pressure is connected to the motor cover 17, and the large oil cylinder 1 is fixed on one fixed seat 18, and the large oil cylinder 1 is fixed on a fixed seat 18. The operation process is as follows.

When injecting the plastic material into the mold, oil is first injected into the small oil cylinder 3 through the oil hole 10, and since the space inside the small oil cylinder 3 is relatively small, the injected oil is The small piston 4 is actuated to quickly move the small piston 4 forward to the left. At this time, the large piston 2 in the large oil cylinder 1 is pushed and moved by the piston rod 5, and at the same time, the large piston 2 in the large oil cylinder 1 is pushed and moved through the oil passages of the oil holes 8 and 9. The controlling electromagnetic valve opens, and the oil on the left side of the large piston 2 flows through the oil hole 9 and the electromagnetic valve to the right side of the large piston 2 from the oil hole 8 without resistance, so that the large piston 2 and the small piston 4 simultaneously flow. It can move forward quickly, moving the piston rod 14 to the left to push the hydraulic motor cover 17, and moving the spiral rod 16 to the left to quickly inject the plastic raw material into the mold. The total volume of oil in the large oil cylinder 1 also remains unchanged. The oil cylinder is completely filled with oil and there is no gap at all, so when the large piston 2 needs to move, the large piston 2 can be moved by pushing the large piston 2 with the oil in the large oil cylinder 1. Can work immediately.

If it is necessary for the small piston 4 to turn to the left and move forward in one step to quickly complete injection of the plastic raw material and apply pressure, close the solenoid valves in the oil passages of the oil holes 8 and 9, and drain the oil from the oil hole 6. The oil is injected into the large oil cylinder 1, but since the space inside the large oil cylinder 1 is relatively large and the cross-sectional area of the large piston 2 is also relatively large, the injected oil faces to the left and pushes the large piston. The large piston 2 moves forward to the left at a relatively slow speed,
At this time, the piston rod 14 turns to the left and generates a relatively large thrust, applying strong pressure to the plastic that has already been injected, so that the effect of pressurizing the plastic is quickly achieved after the plastic is injected. At this time, the small piston 4 and piston rod 5 in the small oil cylinder 3 are pulled by the large piston 2, and at the same time, the electromagnetic valve that controls the oil passages of the oil holes 12 and 13 opens, and the oil on the left side of the small piston 4 is pulled. Since the oil flows from the oil hole 12 to the right side of the small piston 4 through the oil hole 13 and the electromagnetic valve without resistance, the small piston 4 can move forward simultaneously with the large piston 2 at a slow speed. At this time, the total oil capacity of the small oil cylinder 3 does not change, and the oil cylinder is completely filled with oil and there is no gap. If the small piston 4 is pushed and moved with this oil, the small piston 4 can be operated immediately.

The twin oil cylinder, twin piston plastic injection molding machine of the present invention has two large and small oil cylinders 1 and 3 and two pistons 2 and 4 installed in series, so that it can operate powerfully and at high speed. That is, first, the small piston 4 moves quickly and injects plastic into the mold at high speed, and at this time, the electromagnetic valve that controls the oil passages of the oil holes 8 and 9 opens, and the oil in the large oil cylinder 1 is released. goes from oil hole 9 to oil hole 8 without resistance via the electromagnetic valve.
The large piston 2 and the small piston 4 are moved simultaneously at high speed.
If it is necessary to pressurize the plastic material in the mold, the large piston 2 moves to the left at a slow speed to pressurize the plastic material.
The electromagnetic valves that control oil passages 2 and 13 open,
The oil in the small oil cylinder 3 flows from the oil hole 13 through the electromagnetic valve to the right side of the small piston from the oil hole 12 without resistance, causing the small piston 4 and the large piston 2 to move forward simultaneously at a slow speed.

[Effect of idea]

The twin oil cylinder, twin piston plastic injection molding machine of the present invention is extremely practical because high speed movement or low speed pressurization can be selected as required.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a twin oil cylinder, twin piston plastic injection molding machine of the present invention. FIG. 2 is a longitudinal sectional view of an example of the use of the twin oil cylinder, twin piston plastic injection molding machine of the present invention. FIG. 3 is a diagram of the electromagnetic valves installed in the large and small oil cylinders of the twin oil cylinder, twin piston plastic injection molding machine of the present invention. 1...Large oil cylinder, 2...Large piston, 3...Small oil cylinder, 4...Small piston, 5...Small piston piston rod, 6, 7, 8, 9, 10, 11, 12, 13...
...oil hole.

Claims (1)

[Scope of utility model registration request] A twin oil cylinder twin piston plastic injection molding machine, which has a large oil cylinder, a large piston, a small oil cylinder, and a small piston, the inner diameter of the large oil cylinder is larger than the inner diameter of the small oil cylinder, and The outer diameter of the piston is larger than the outer diameter of the small piston, the large piston and the small piston are installed in the large oil cylinder and the small oil cylinder, respectively, and the large oil cylinder and the small oil cylinder are axially connected to each other. The piston rod of the small piston and the large piston are connected to each other in the axial direction, and the large oil cylinder and the small oil cylinder are each provided with four oil holes, and the four oil holes are distributed on both sides of each piston, one solenoid valve controls the oil passages of the two oil holes on both sides of the piston of the large oil cylinder, and another solenoid valve controls the oil passages of the two oil holes on both sides of the piston of the large oil cylinder. A plastic injection molding machine characterized by controlling oil passages of two oil holes on both sides of a piston.