JPS58109704A - Oil pressure driving gear - Google Patents

Abstract

PURPOSE:To eliminate a circulating pump for liquid to be purified by a system wherein an electrostatic purifying tank is provided in the branch circuit of the discharge side circuit of a pump in the hydraulic drive gear to circulate working oil by means of an oil circulating pump. CONSTITUTION:The accompanying figure shows an example of a hydraulic drive gear employed in an injection molding machine. The oil circulating pump 5' sucks up the working oil in an oil tank 6 through a strainer 7 and sends it to selector valves 8 and hydraulic cylinders 9. Return oil is sent through an oil cooler 10 back to the tank 6. In this case, the branch circuit 12 is branched off the discharge side circuit of the oil cooler and communicated through a closing valve 13 to the purifying tank 11. Because the filter 17 within the purifying tank 11 is connected to DC high tension power source, particles in the oil passing through the branch circuit 12 are polarized and electrified and then adsorbed to the filter 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic unit 1/device that operates by circulating hydraulic oil with an oil feed pump, and its purpose is to efficiently and safely purify the hydraulic oil. It's about doing.

Conventionally, in hydraulic drive devices such as injection molding machines, oil purification of hydraulic oil is mainly performed using a filtration type filter, and it is necessary to replace the oil with new oil every year or so. It's a big burden. Recently, it is known that particles with a particle size of 6μ or less can act as a catalyst that accelerates oil deterioration, and due to the soaring price of oil, electrostatic - Type oil purifiers have been developed and are becoming popular.

This electrostatic oil purifier applies a ξ voltage between opposing electrodes to generate an electric field, and by passing the oil to be purified through this electric field, it can remove even fine particles with a particle size of 5 μm or more using static electricity. It consists of a septic tank and a pump for circulating the oil to be purified. However, since the pump for circulating the oil to be purified accounts for a large portion of the cost in the electrostatic oil purifier and is expensive, generally an injection molding machine as a hydraulic drive device and an electrostatic oil purifier are used. The system is constructed separately from the hydraulic drive system, and the hydraulic drive units connected to it are changed every few days to purify the hydraulic oil in the oil tank of each hydraulic drive unit.Figure 1 shows the process for cleaning oil. Show the situation, rl>
is a hydraulic drive device f1. such as an injection molding machine. +2I is the septic tank and pump, (5) is the pump of the hydraulic drive device (1). Because of this structure, the hydraulic oil in one oil-boosting device is not purified all the time, so by the time it is purified the next time, the contamination may have progressed, so it must be done frequently. It is necessary to connect the electrostatic oil purification device to each hydraulic drive device for oil purification. Furthermore, if an electrostatic septic tank M12) is provided for each hydraulic drive device, not only will the cost of the hydraulic drive device (11) increase significantly, but the device will also become larger.

Therefore, the present invention provides an electrostatic purifier by interposing an electrostatic septic tank in a circuit branched from the main circuit on the delivery side of the oil pump of a hydraulic drive device that operates by circulating hydraulic oil with an oil pump. Low cost, no need for a pump for circulation of the liquid to be purified on the oil equipment side.
This is a compact and efficient oil purification system, and one embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

(1') is the injection molding machine body, (5' is the injection molding machine body (
One oil feed pump (6) is a hydraulic oil tank, and is piped to the eleventh oil feed pump (6') via a strainer (7). (8) (9) is a switching valve and a hydraulic cylinder connected to the oil sending side of the oil pump (5 units), and the return oil from the switching valve (81) passes through the oil cooler QQ and returns to the tank (6 units).

The east side is the septic tank and the oil pump (main circuit on the sending side of 5 liters (b)
It is connected to a branch circuit port branched from the delivery side of the oil cooler α1 and returned to the tank (6).

The valve is an on-off valve installed at the branch circuit port.

Figure 4 shows a longitudinal cross-sectional view of the east side of the septic tank, where the curve is the inlet connected to the delivery side of the oil cooler αq via the on-off valve (to), αG is the outlet, and the middle is the nonwoven fabric between the Wl poles. The intervening filter is connected to the output of the DC blind voltage source a field through the high perspiration contact piece.

The handle is the liquid level switch, (2) is the lid plate, and (2) is the drain.

Note that the hydraulic pressure on the delivery side of the main circuit fluctuates due to the movement of the hydraulic cylinder (9), and the application of medicine also changes accordingly.
Here, the average value is adjusted to the appropriate amount of oil purification to maintain the oil purification ability.

With this configuration, the hydraulic circuit separates coarse dust from the tank (6 voices) using the strainer (7), and separates coarse dust from the oil pump (5/5).
) The hydraulic oil pumped up into the valve (8) enters the switching valve (8), which controls the hydraulic cylinder (9) to inject the wood sushi and open/close the mold. The return oil that has exited the switching valve (3) is returned to the tank (6) via the oil cooler 00. On the other hand, the return oil that has entered the branch circuit side from the main circuit is connected to the inlet (towards).
The oil flows into the septic tank Qn, passes through the filter Qη, and returns to the tank (6) from the outlet Ql. However, when passing through the filter Qη, the particles in the oil are polarized and charged due to the high electric field, and the particles in the oil are polarized and charged.
The dust is adsorbed and collected by the nonwoven fabric within η. In this way, the oil passing through the branch circuit port is constantly purified, so the hydraulic oil in the tank (6) is gradually purified, and sufficient performance can be obtained despite the small size. Moreover, since the temperature of the hydraulic oil in the hydraulic circuit is approximately 50° C. and the viscosity of the oil is not particularly high, dust in the oil is easily separated and collected. Since the septic tank αυ is placed in the branch circuit mouth, the internal pressure inside the tank can be kept to a low level, and it can be made from a thin copper plate.
Even if the flow path of υ were to be blocked for some reason, the flow in the main circuit would not be affected, and the injection molding machine would not become inoperable due to this. In addition, since the oil pump (to) of the hydraulic circuit is branched from the delivery side, as long as the oil feed pump is in operation, the purification flIIQIl
Oil flows through the septic tank aυ, and the oil flow and the internal pressure of the septic tank aυ can be adjusted by making the diameter of the pipe on the four sides of the inlet of the branch circuit smaller. Because the oil cooler is branching out after the cry,
The oil pressure can be kept low and the oil temperature will not be too high and have a negative effect on the filter screen, allowing oil to be purified at an appropriate temperature.

The on-off valve 0 is used to close the branch circuit O when periodically inspecting the inside of the septic tank GN while the injection molding machine (1') is in operation, or when opening the cover plate to replace the filter α. This can also be used to control the amount of water flowing into the septic tank to improve oil purification efficiency.

As explained above, according to the present invention, it is possible to eliminate the pump for circulating oil to be purified, which was required on the electrostatic oil purifier side in addition to the pump of the hydraulic drive device. It is possible to keep the hydraulic oil clean by purifying the
The precision of the machine is good, there is no oil leakage due to excessive pressure increase, and the life of the hydraulic oil and machine can be extended.

In addition, although the septic tank is installed on the delivery side, which generally has high oil pressure, the septic tank is installed in a circuit branched from the main circuit, so the longer the pipeline on the inlet side of the septic tank, the more The smaller the diameter of one piping path, the lower the internal pressure of the septic tank can be kept, and the thinner the septic tank can be designed, the more cost can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of oil purification work of a conventional hydraulic drive device, Fig. 2 is a front F71+ view of an injection molding machine according to an embodiment of the present invention, and Fig. 8
The figure is a hydraulic system diagram of FIG. 2, and FIG. 4M is a main part configuration diagram of FIG. 2. (1')...Injection molding machine body, (5')...Oil pump, (6)...Tank, (7)...Strainer,
(8)...Switching valve, (9)...Hydraulic cylinder, Ql
l...Oil cooler, Qto0. Septic tank, (1z...
Branch circuit, Q3-・Opening/closing valve, 04...Main circuit agent
Yoshihiro MorimotoFigure 1Figure 3Figure 4

Claims (1)

[Scope of Claims] 1. Hydraulic pressure w that operates by circulating hydraulic oil through the oil pump, in a circuit branched from the main circuit on the oil pump delivery side of the III device! [Hydraulic drive system equipped with a type septic tank. 1. A hydraulic drive system for a filling and recording machine according to claim 1, in which an electrostatic septic tank is interposed in a circuit branched from an oil cooler delivery port provided in a main circuit on the delivery side of an oil pump.