JPS61219459A - Detection of galling at plunger tip in injection mechanism - Google Patents

Abstract

PURPOSE:To detect surely the galling state of a tip by judging the presence of the galling state between the tip and sleeve unless the contact of a coupling with a frame is detected upon detection of the return of the frame. CONSTITUTION:A molding material 9 stored in the sleeve 7 is forced by the plunger tip 4 into a metallic mold 8 and thereafter the plunger 3 and tip 4 are pulled back by a piston 2. If the tip 4 and the sleeve 7 are galled, the push back force of the piston 2 acts in the order of the coupling 5 plunger 3 tip 4 sleeve 7 frame 6 and pulls down integrally the frame 6. The 2nd position detector 13 detects the return of the frame 6 accordingly but the 1st position detector 15 does not detect the contact of the coupling 5 and the frame 6. The presence of the galling state between the tip 4 and the sleeve 7 is therefore judged and a pressure supply source 10 and a cylinder 1 are emergently shut off to stop the movement of the plunger 3 by which the action of the return force of the piston 2 between the tip 4 and the sleeve 7 is averted.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is applicable to a molding machine 1 having a mechanism for storing molding material in a sleeve and press-fitting it into a mold with a plunger tip, for example, in an injection mechanism of a die casting machine. The present invention relates to a galling detection method for a plunger tip.

[Conventional technology]

Figure 2 shows the injection mechanism of a vertical die-casting machine.
After filling the mold (not shown) with the molding material,
This shows the injection system returning to its original position.

In Fig. 2, a plunger tip (hereinafter referred to as a tip) 4 is slidably mounted on a sleeve 7 fixed to a frame B.
A plunger having a cylinder 1 is connected to a piston 2 and a piston rod 2a of a cylinder 1 by a coupling 5, and is operated. Here, the cylinder 1 consists of a ram part 1a that supports the frame 6 by hydraulic pressure, and a cylinder body part 1b that operates a plunger. The sleeve 7 and the mold located above are brought into contact during the injection stroke.

After injection, in order to return the injection system to the original position from the state where the sleeve 7 and the mold are in contact, the switching valve 10a is activated to supply hydraulic pressure from the hydraulic pressure supply source 10 to the rod side of the cylinder 1.
The head side may be opened to 12 in the evening. Then,
The plunger 3 begins to return (descend in Figure 2), but in the middle of this, the coupling 5 comes into contact with the bottom of the frame O.
The entire frame 6 that holds the sleeve 7 will be hooked up and returned. At this time, the frame 6 returns while being supported by a force in two directions in Figure 1 with a force corresponding to the pressure set in the IJ-F valve 11 provided in the hydraulic circuit of the ram 1a. FIG. 2 shows the injection system returned to its original position.

In another prior art technique shown in Japanese Utility Model Application No. 58-96852, there is a device shown in FIG. A detector 1 and a position detector 14 such as a limit switch for detecting the retraction limit of the piston 2, that is, the injection return limit are provided.

From the state shown in Fig. 2, the plunger is moved by the piston 2.
When the tip 4 is pulled back, if the tip 4 and the sleeve 7 are engaged, that is, if they are fixed, the pulling force from the hydraulic pressure source 10 of the piston 2 will be applied to the coupling 5 → plunger roller → tip 4 → sleeve 7 → frame Acting in the order of (B), the frame 6 is pulled down integrally while resisting the force due to the pressure set in the relief valve 11.

[Problem that the invention seeks to solve]

The molding material is generally used for die casting machines.

An aluminum alloy is used, and for the purpose of increasing fluidity (lowering viscosity), it is kept at a high temperature and stored between the sleeves 7 for injection and filling. Therefore.

The amount of heat propagates to the sleeve 7 and the chip 4, and if the cooling conditions are bad, the two will become stuck (galled) due to expansion or welding. If it is possible to detect that this galling has occurred, the sleeve 7 or the tip 4 can be quickly cooled down to restore normal operation, but even though galling has already occurred,
When the plunger is pulled back as described above, instead of the coupling 5 pulling the frame 6 away, the tip 4 pulls down the sleeve 7, so the frame 6 comes into contact with the top surface of the cylinder 1, and as a result, The force exerted by the hydraulic pressure source 10 acts directly between the tip 4 and the sleeve 7, further worsening galling. In this case, even if the tip 4 and sleeve 7 are cooled, it is difficult to separate them because they are mechanically wedged, and under adverse conditions, the plunger, coupling, etc. 5. Even if the frame is 6″!, it may even lead to damage.

Conventionally, methods have been proposed to detect the galling state of the tip 4 by detecting pressure fluctuations (increases) acting on the rod side of the cylinder 1 from the hydraulic pressure supply source 10, but the accuracy is limited. The above problems remained and it was not functioning adequately.

Furthermore, in the above-mentioned another conventional technique, the above-mentioned two position detectors 13. Originally, L4 should be turned on almost simultaneously.

When biting in this way, even if position detector 1 is turned on, position detector 14 remains off. When this condition is met, the hydraulic pressure supply source 10 and the cylinder 1 are urgently cut off, the movement of the plunger B is stopped, and the frame 6 is moved to the cylinder 1.
A situation in which the returning force of the piston 2 generated by contacting the upper surface acts between the tip 4 and the sleeve 7 is avoided.

Here, we used the expression ``normally, the chip 4 galling is detected at the timing of 0N10FF of the two position detectors 13.14, but the bottom position detectors 13.14 should operate almost at the same time'', but we will explain it in detail. Then 1 position detector 13
The operation is more reliable if the position detector 14 is set to operate a little earlier, for example, by setting the amount of movement of the piston 2 to about 1 to 10. Further, as is clear from the above description, since the piston 2 returns against a considerable amount of the force due to the pressure of the relief valve 11, the tip 4 and the sleeve 7
In the meantime, this force will act in a direction that promotes galling, but its value is.

It only serves to prevent the frame 6 from falling under its own weight, and is so small that it can be ignored.

Furthermore, in the conventional invention, a signal indicating that the injection system has completely returned to its original position is obtained by detection by one position detector. This is because, as mentioned above, the position detector 14 must be activated slightly earlier than the original original position.

Although the above methods are practical, they are not perfect. This is because the 1st position detector 14 is set to operate earlier than the 5th position detector 1.
If 4 is detected first, it is not chip galling, so in the meantime, (2) when the chip is galled, there is a blind spot that cannot be detected, and (2) even if the connection between the hydraulic pressure supply source 10 and the injection cylinder 1 is urgently cut off.

Since its operation takes time, the piston 2 flows. Therefore, if possible, we would like to make a large space between the two position detectors 14 and 13, respectively.

Conflicting conditions ■←→■ occur, so 1 position detector 1
4 and the position detector 13 become extremely troublesome.

[Means for solving problems]

The present invention has been made to solve one or more of the problems mentioned above, and is aimed at reliably detecting chip galling.

To this end, the present invention includes two position detectors that detect when the frame has returned, a third position detector that detects when the cylinder piston has returned, and a third position detector that detects when the coupling has contacted the frame. A first position detector was arranged, and the presence or absence of galling was detected by a combination of these ON/OFF signals.

[For production]

If the first position detector does not detect that the coupling has come into contact with the frame when the second position detector detects that the frame has returned.

It is determined that the frame has returned before the coupling comes into contact with the frame, that is, it is known that the tip and the sleeve are fixed to each other, and at this point, the tip is detected as being steered.

〔Example〕

Next, the present invention will be explained in more detail with reference to one embodiment shown in one drawing.

FIG. 1 shows an embodiment of a device for carrying out the present invention, in which 1 is an injection cylinder, Ia is a ram portion fixed to the rod side of the injection cylinder 1, 2 is a piston of the injection cylinder 1, and 2a is a ram portion fixed to the rod side of the injection cylinder 1. is the piston rod, the bottom is the plunger, 4 is the plunger tip, 5 is the plunger bottom and the piston rod 2
A coupling that connects a, 6 a frame, 6a
7 is a cylinder portion of the frame 6 into which the tip of the ram 1a is inserted, and 7 is a sleeve fixed to the tip of the frame 6. A tip 4 is slidably inserted into the sleeve 7. 8 is the mold.

9 is an injected molded material such as aluminum alloy.

10 is a hydraulic power source, 10a is a switching valve, 11 is an IJ valve, 12 is a tank, and 13 is a position detector (referred to as a second position detector) that detects when the frame 6 has returned to its original position or its vicinity. ), 14 is a position detector (referred to as a third position detector) that detects the state in which the cylinder piston 2, which slides the chip 4 against the sleeve 7, has returned to its original position.

Reference numerals 1 and 5 indicate position detectors (referred to as first position detectors) that detect the relative position between the frame 6 and the plunger O.
A first position detector 15 is provided, and a first position detector 15 is provided.
If it turns ON, it is known that the coupling 5 is in contact with the bottom of the frame 6, and the first position detector 15 turns OFF.
If.

It can be seen that the coupling 5 is not in contact with the bottom of the frame 6.

In this way, in the present invention, the coupling 5 is attached to the frame B.
A first position detector 15 is provided that detects when the contact occurs.

From the state shown in Fig. 1, piston 2 causes plunger B,
When chip 4 is pulled back.

□If the tip 4 and the sleeve 7 are engaged, that is, fixed, the pullback force of the piston 2 by the hydraulic pressure supply source 10 acts in the order of the coupling 5 → plunger 6 → tip 4 → sleeve 7 → frame 6, and the relief While resisting the force due to the pressure set on valve 11.

The frame 6 will be pulled down as one piece.

At that time, when the second position detector 1 was detected.

First position detector 15. That is, if the contact between the coupling 5 and the frame 6 is not detected, it means that the sleeve 7 and the tip 4 are in a fixed state, so the pressure supply source 10 and the cylinder 1 are urgently shut off. Then, the movement of the plunger O is stopped, and the returning force of the piston 2 generated by the frame 6 coming into contact with the upper surface of the cylinder 1 is applied to the tip 4.
This avoids the situation where the sleeve 7 acts between the sleeve 7 and the sleeve 7. here.

Even if the piston 2 flows during an emergency stop, there is no problem in activating the second position detector 13 early in anticipation of this. This is because since the first position detector 15 is placed on the frame 6, it directly observes the relative relationship between the frame 6 and the coupling 5, so it cannot become a blind spot for detection. be. Moreover, the injection system has returned. In other words, how do you know when it has returned to its original position?

A third position detector 14 that is completely independent of the chip galling detection circuit consisting of the first and second position detectors 15 and 13.
Since there is no interdependence in control, it is safe.

〔effect〕

Since the present invention has been made as described above, the present invention is as conventional.

For example, compared to methods that involve many uncertainties such as knowing the pressure, the detection ability is significantly improved.

Moreover, 0N10 of position detectors such as limit switches etc.
Since it only involves the timing of the FF, it is inexpensive, reliable, and simple.

Furthermore, there are no blind spots at all, making it easy to adjust the angle.

Also, the first and second stations are the ones that know that the injection system has returned.
Since the information is obtained from a third position detector that is completely independent of the chip galling detection circuit consisting of the position detector, there is no interdependence in control, and it is safe.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a device for carrying out the present invention, and FIG. 2 is a longitudinal sectional view showing an example of a conventional device. 1...Injection cylinder, 3...Plunger. 4... Plunger chip, 6... Frame. 7... Sleeve, 8... Mold, 13... Second position detector, 14... Position detector shown in FIG. 3. 15...First position detector.

Claims (1)

[Claims] a first position detector that detects the relative position of the frame supporting the sleeve and the plunger; a second position detector that detects the state in which the frame has returned to its original position or its vicinity; The cylinder piston, which slides the plunger tip fixed at the tip against the sleeve, includes a third position detector that detects when the cylinder piston returns to its original position. When the return of the plunger to the frame is detected and the first position detector does not detect the return of the plunger to the frame, it is determined that the sliding between the plunger tip and the sleeve is abnormal, and the operation is urgently stopped. In the injection mechanism, the injection mechanism is characterized in that an abnormality is displayed, and the detection signal of the third position detector is used as a signal for determining that the plunger and the frame have truly returned to their original positions. How to detect galling of plunger tip.