JPH0438565B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct pressure type mold clamping device that can be applied to injection molding machines, die casting machines, etc.

FIG. 1 is a side sectional view showing a conventional mold clamping device. In the figure, 1 is a mold clamping cylinder into which a main ram 2 is slidably inserted. The main ram 2 integrally fixes a movable mold (not shown). 3 is boosterum,
It is integrally fixed to the mold clamping cylinder 1 by bolts or the like (not shown), and the front part is slidably inserted into the pressure receiving chamber 4 of the main ram 2, and has a boost oil passage 5.

6 is a pre-filled piston, and a pre-filled closing spring 7 is loaded between it and the rear part of the booster ram 3, and the protruding part 8 at the front part is in a sealable relationship with the rib 1a of the mold clamping cylinder 1, and The piston portion 9 is slidable on the mold clamping cylinder 1.
Further, 10 indicates a pressure increasing oil passage. Reference numeral 11 denotes a pressurizing oil hole, which is formed at the rear of the booster ram 3.
Reference numeral 12 denotes a prefill opening oil hole, which is formed in the mold clamping cylinder 1. 13 is a mold clamping oil hole formed in the mold clamping cylinder 1, and 14 is an oil passage that communicates the interior of the mold clamping cylinder 1 with an oil tank (not shown).

In the device shown in FIG. 1, during the forward and backward movement of the prefill piston 6, which opens and closes oil sent from an oil tank (not shown) into the mold clamping cylinder 1,
The movement of the seal surface 8a is moved forward by the force of the spring 7 and the speed of the piston 6 due to the hydraulic pressure from the boosting oil hole 11.
a and is stopped, and for retraction, pressure oil is sent to the oil hole 12, and at a constant speed it is brought into contact with the protrusion 3a of the booster ram 3 and stopped. For this reason, speeds are controlled by taking into account the vibration, noise, and strength of impact during a collision, and the shortening of the driving cycle due to higher speeds is limited to a certain extent.

The present invention was proposed to solve the above-mentioned conventional drawbacks, and includes a main ram fitted into a mold clamping cylinder, a booster ram fitted into the main ram, and a press that is fitted into the mold clamping cylinder and moves back and forth. In a mold clamping device such as an injection molding machine, which is provided with a fill piston and configured such that the front protrusion of the pre-fill piston and the rib of the mold clamping cylinder are in liquid-tight contact with each other,
A cushion back pressure chamber a, which constitutes a cushion portion during forward movement, is formed between a protrusion provided on the outer periphery of the rear piston portion of the pre-filled piston and a stepped portion on the inner circumferential surface of the mold clamping cylinder. There is a throttling space b between the pressure chamber a and the discharge hole 12 provided in the mold clamping cylinder.
A cushion back pressure chamber c constituting a cushion section at the time of retraction is formed between the rear surface of the rear piston section and the booster ram rear inner peripheral surface stepped section 16, and the back pressure chamber c, A throttling gap d is formed between the prefill piston and the space 15 formed between the booster ram, allowing high-speed operation, and creating a throttling back pressure with the oil escaping through the throttling gap. The purpose is to provide a mold clamping device.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 2 to 7 show embodiments of the present invention, and 1
3 is a mold clamping cylinder, 3 is a booster ram, 6 is a prefill piston, 7 is a spring for closing the prefill, 9 is a rear piston part, 10 is an oil passage for increasing pressure, 12 is an oil hole for opening the prefill, and these are the first Since it is the same as the figure, the explanation will be omitted here.

Now, FIG. 2 shows a state in which the pre-filled piston 6 is advanced, and has a cushion portion A. The cushion portion A is a cushion back pressure chamber a that constitutes a cushion portion during forward movement between a protrusion 6a provided on the outer periphery of the rear piston portion 9 of the pre-filled piston 6 and a stepped portion on the inner circumferential surface of the mold clamping cylinder 1. At the same time, a throttle space b is provided between the back pressure chamber a and the discharge hole 12 provided in the mold clamping cylinder 1.

FIG. 3 shows the pre-filled piston 6 in a retracted state, and has a cushion portion B. FIG. The cushion portion B forms a cushion back pressure chamber c, which constitutes a cushion portion during retraction, between the rear surface of the rear piston portion 9 of the pre-filled piston 6 and the rear inner circumferential surface stepped portion 16 of the booster ram 3. The same back pressure chamber c,
A throttle space d is provided between the prefill piston 6 and the space 15 formed between the booster ram 3.

Next, to explain the action, the prefill piston 6
When approaches the forward end, the oil in the back pressure chamber a flows as shown by the dotted line in FIG. At this time, this oil is used for squeezing.
The throttle is tightened, creating back pressure and creating a braking effect that prevents high-speed collisions.

Next, when the prefill piston 6 approaches the retreating end, the oil in the back pressure chamber c flows as shown by the dotted line in FIG.
At this time, this oil is squeezed through the throttling interval d, creating back pressure and exerting a braking effect to prevent collisions at high speeds.

As explained above, in the present invention, high-speed operation is possible due to the braking effect when the pre-filled piston approaches the forward end or the backward end, and the operating cycle can be shortened.

[Brief explanation of drawings]

Figure 1 is a side sectional view showing a conventional mold clamping device;
3 and 3 are side sectional views of mold clamping devices showing embodiments of the present invention in different operating states. Explanation of main parts of the figure, 1...mold clamping cylinder, 1a
...Rib, 2...Main ram, 3...Booster ram, 6...Prefill piston, 7...Prefill closing spring, 9
... Rear piston section, a, c... Back pressure chamber, b, d... Throttle space.

Claims (1)

[Claims] 1 A main ram is fitted into the mold clamping cylinder, a booster ram is fitted into the main ram, and a pre-filled piston is fitted into the mold clamping cylinder and moves back and forth, and the front protrusion of the pre-filled piston and the same mold clamping In a mold clamping device of an injection molding machine or the like configured to contact the ribs of a cylinder in a liquid-tight manner, a protrusion provided on the outer periphery of the rear piston portion of the pre-filled piston and a stepped portion on the inner peripheral surface of the mold clamping cylinder. A cushion back pressure chamber a constituting the cushion portion during forward movement is formed between the two, and a throttle space b is formed between the back pressure chamber a and the discharge hole 12 provided in the mold clamping cylinder.
A cushion back pressure chamber c is formed between the rear surface of the rear piston portion and the booster ram rear inner circumferential surface stepped portion 16, and the cushion back pressure chamber c constitutes a cushion portion at the time of retraction.
A mold clamping device characterized in that a drawing space d is formed between the back pressure chamber c and a space 15 formed between the prefill piston and the booster ram.