JPS5867364A - Oil cleaning device for hydraulic machine - Google Patents

Abstract

PURPOSE:To reduce equipment costs by providing a branch circuit to an oil hydraulic circuit in an oil hydraulic apparatus such as an injection molding machine, and installing an electrostatic type oil cleaner in the branch circuit. CONSTITUTION:A branch circuit 13 is branched from the main circuit 4 on the delivery side of an oil feed pump 3 in an oil hydraulic circuit of an injection molding machine, and an electrostatic type oil cleaner 1 is installed in the mid- way thereof. The working fluid which is separated of coarse particles of dust with a strainer 6 from a tank 5 enters a selector valve 7 which controls an oil hydraulic cylinder 8, thereby performing injection of resins, etc. and opening or closing of dies. The return oil out from the valve 7 is returned into the tank 5 by passing through a cooler 9. In this case, the return oil entering the circuit 10 branched from the circuit 4 flows through the cleaner 1 before entering the tank 5. A requlating means 12 which makes the pipe bore of a branch circuit 11 on the feed side smaller then the pipe bore of the branch circuit 13 on the delivery side is provided in order to regulate the flow rate and pressure of the oil on the feed side of the cleaner 1, whereby the internal pressure of the oil is reduced. The costs of equipment are reduced by the reduced wall thickness design over the entire part of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electrostatic oil purifier installed in the hydraulic circuit of a hydraulic machine such as an injection molding machine to effectively purify hydraulic oil and the like at a much lower cost. This relates to oil equipment.

Conventionally, oil purification of hydraulic oil for hydraulic machines such as injection molding machines, turbine oil, etc. has been mainly performed using vortex filters, but the complete filter set cannot remove particles with a particle size of 5μ or less. However, it has recently become known that particles smaller than 5μ can act as catalysts that accelerate oil deterioration.
In addition, due to the rising price of oil, electrostatic oil purifiers have been developed and are becoming popular. However, although electrostatic oil purifiers are useful for users because they can remove particulates, have a long oil life, and have low running costs, they have had problems in terms of price. In addition, since the oil purifier is changed every few days to clean the oil, it is necessary to move the oil purifier from time to time.Furthermore, since the same oil is not being purified all the time, the next oil needs to be purified. By the time the oil was removed, the contamination may have progressed, so it was necessary to purify the oil frequently.

The present invention solves the above-mentioned conventional drawbacks, and one embodiment thereof will be described below with reference to the accompanying drawings.

In the figure, 1 is an electrostatic oil purifier fixed to the injection molding machine main body 2, and as shown in the hydraulic system diagram shown in FIG. Main circuit 4
Distributed in a more branched circuit, via a strainer 6,
Piping is provided from the tank 5 to the pump 3. Further, the oil feeding side of the pump 3 is piped to a switching valve 7 and a hydraulic cylinder 8, and the return oil from the switching valve 7 returns to the tank 5 via a cooler 9.

Further, an electrostatic oil purifier 1 is disposed in a branch circuit 10 branched from the main circuit 4 on the delivery side of the pump 3 of the hydraulic circuit, and the electrostatic oil purifier 1 is located on the inlet side of the branch circuit 10 .

11 is an adjustment means 12 consisting of a valve that adjusts pressure and flow rate.
The branch circuit 13 on the sending side is returned to the tank 5.

FIG. 3 shows an electrostatic oil purifier 1, in which 21 is a main body, an inlet 22. Outlet 23. A drain 24 is provided.

Reference numeral 25 denotes a filter with a nonwoven fabric interposed between electrodes, and is connected to a high voltage power supply circuit 27 via a high voltage contact piece 26. 28 is a liquid level switch, and 29 is a lid.

In the above configuration, in the hydraulic circuit of the injection molding machine 2, the hydraulic oil that is separated from the tank 5 by the strainer 6 and pumped up to the pump 3 enters the switching valve 7, where it controls the hydraulic cylinder 8. Injects resin and opens and closes molds. The return oil flowing out from the switching valve 7 passes through a cooler 9 and is returned to the tank 5.

Return oil entering a branch circuit 10 branched from the main circuit 4 passes through the electrostatic oil purifier 1 and returns to the tank 5.

Oil that flows into the electrostatic oil purifier 11 from the inlet 22 exits through the filter 26 and outlet 23, but when passing through the filter 25, particles in the oil are polarized and charged due to the high electric field. The dust is adsorbed and collected by the nonwoven fabric in the filter 25. Since the electrostatic oil purifier 1 purifies the oil passing through the branch circuit 10,
The oil in the tank 15 is being gradually purified, but since it is permanently installed, it has sufficient performance even though it is small. Moreover, the temperature of the hydraulic oil in the hydraulic circuit is approximately 50°C, and the viscosity of the oil is not particularly high, so dirt in the oil can be easily separated and collected.

The hydraulic circuit originally requires a pump, but in order to divert oil from a molding machine and other equipment to flow oil into the electrostatic oil purifier 1, a stationary type oil purifier does not require its own pump. Even if a situation were to occur where the injection molding machine became blocked due to some abnormality, the flow of the main circuit would not be affected and the injection molding machine would not stop.

In addition, since the feed-side branch circuit 11 is provided with the adjustment means 12, the flow rate of oil passing through the electrostatic oil purifier 1 is increased.

The pressure can be reduced and the oil in the electrostatic oil purifier 1 can be adjusted to an appropriate amount to optimize the oil purification capacity. Furthermore, the high pressure of several tens of atmospheres in the main circuit 4 is throttled down by the adjustment means 12 provided in the feed side branch circuit 2Q. The main body 21 and the lid 2 are capable of suppressing the internal pressure due to oil to 1 atmosphere or less.
9 thin wall design can be achieved, significantly reducing costs.

In addition, if a thin adjustment tube with an inner diameter of 7 mm or less is provided in the feed-side branch circuit 21 as an adjustment means, the tube is thin and has a large resistance to oil with high viscosity, so the length must be several tens of meters. −
By doing so, the pressure and flow rate can be reduced in the same way as the adjustment means 12, and the adjustment pipe can be bent into a circular shape.

When the pipe inner diameter of the feed-side branch circuit 11 is made smaller than the pipe inner diameter of the feed-side branch circuit 13, the internal pressure of the electrostatic oil purifier 1 can be lowered and the flow rate can also be adjusted to a small value.

As described above, according to the present invention, an electrostatic oil purifier is placed in a branch circuit branched from the delivery side of an oil feed pump in a hydraulic circuit of a hydraulic machine such as an injection molding machine, thereby reducing the cost. The oil feed pump, which occupies most of the weight, can be removed from the electrostatic oil purifier and can be permanently installed, making it possible to provide a compact and inexpensive device. In addition, since the oil is constantly purified, the oil is always purified and kept, the precision of the machine is good, there is no oil leakage due to excessive pressure increase, and the life of the machine can be extended as well as the life of the oil. Even though it is installed on the delivery side of the oil pump, which is in trouble, there is pressure 'rN, f-7:' on the delivery side of the circuit that is branched from the main circuit.
, the pressure and flow inside the electrostatic oil purifier are provided.
Since k can be adjusted, electrostatic oil purifiers can be designed using thin-walled steel plates, making it possible to provide inexpensive products, and by being able to adjust the flow rate, the oil purification capacity can be increased to match the optimal flow rate. It has been shown to have excellent effects such as the ability to

[Brief explanation of drawings]

Fig. 1 is a side view of an electrostatic oil purifier according to an embodiment of the present invention installed in an injection molding machine, Fig. 2 is a hydraulic system diagram of the same, and Fig. 3 is a diagram of the same electrostatic oil purifier. FIG. 1... Electrostatic oil purifier, 2... Hydraulic machine (
injection molding machine), 3... oil pump, 4...
... Main circuit, 5 ... Tank, 10 ... Branch circuit, 12 ... Adjustment means. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (2)

[Claims] (1) An electrostatic oil purifier is placed in a branch circuit branched from the delivery side of the oil pump in the hydraulic circuit of a hydraulic machine, and pressure and flow rate adjustment means are installed on the delivery side of this branch circuit. Oil purification system for hydraulic machinery installed. (2) Claim 1, in which the inner diameter of the pipe on the inlet side is made smaller than the inner diameter of the pipe on the delivery side as the upper IT adjustment means.
Oil purification device for hydraulic machinery as described in Section 1.