JP2008030232A - Air bubble removing device of hydraulic oil of injection molding machine and hydraulic oil tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bubble removing device of hydraulic oil of an injection molding machine constituted so as not only to efficiently separate air bubbles in the return oil refluxed to a hydraulic oil tank by a centrifugal force by providing a swirl channel in its main body but also to sufficiently separate and remove air bubbles even in a small capacity hydraulic oil tank. <P>SOLUTION: This bubble removing device of the hydraulic oil is composed of a gas-liquid separation pipe composed of an outer pipe having a large number of outflow holes provided in its pipe periphery and the inner pipe provided in the central part of the outer pipe and a cylindrical main body the interior of which is demarcated into upper and lower chambers having opening parts on one sides of them by a floor plate. The lower end part of the gas-liquid separation pipe is inserted in the upper chamber of the main body to form a flow port in adjacent relation to the opening parts. The boundaries of the flow port and the opening parts are cut off by partition pieces to form the swirl channel. An inflow port is provided in the lower chamber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bubble remover for hydraulic oil of an injection molding machine that removes bubbles in hydraulic oil returned to a tank from a hydraulic circuit by a centrifugal force, and a hydraulic oil tank including the bubble remover.

  The hydraulic circuit of the injection molding machine is configured as illustrated in FIG. 5, and the hydraulic oil stored in the lowest tank 100 is sucked up by the pump 101, and the nozzle touch is performed by switching the control valve in the circuit. The cylinder 102, the injection cylinder 103, the oil motor 104, and a mold clamping cylinder and a protruding cylinder (not shown) are pressure-fed (solid arrows). The oil (dotted arrow) discharged from each cylinder and oil motor is returned to the tank 100.

  The bubbles in the hydraulic oil are generated in the process of flowing through the circuit, but until now, the amount of hydraulic oil used is large, so natural degassing in the tank is sufficient to remove the bubbles. It was. However, the amount of oil used decreases due to the use of electric motors for mold clamping and projecting drive and the improvement of work efficiency, and if the tank capacity is reduced accordingly, the time required to store hydraulic oil in the tank is shortened. Thus, it is sucked up by the pump with insufficient natural defoaming and pumped to the hydraulic circuit. When the hydraulic oil containing bubbles is compressed by the pump, noise is generated and the hydraulic control varies. For this reason, there is a demand for means capable of efficiently removing bubbles of hydraulic oil even when the tank capacity is reduced.

As a means for removing bubbles contained in oil using a swirl flow, the cross section perpendicular to the central axis is circular, the diameter of the cross section is reduced toward the oil flow direction, and the frustoconical shape is closed at both ends. There is a bubble removing device that includes a swirling flow chamber and a bubble removing pipe installed at the center of the swirling flow chamber.
JP-A-3-123605 JP-A-5-296018

  In the above bubble removing device, oil containing bubbles is introduced into the tangential direction of the swirling flow chamber by a pump, and the oil flow in the swirling flow chamber is changed into a vigorous swirling flow to reduce oil containing a large amount of bubbles and bubbles. The oil contained in the concentration is separated by the specific gravity difference. Oil containing a large amount of bubbles gathered in the central axis of the swirling flow due to the difference in specific gravity passes through the bubble removal tube through the bubble removal tube and is sucked or dropped into the oil pan where the reflux oil is stored from the top or bottom of the tube. The oil flows out and is removed, and is sent again to the swirl flow chamber by the pump together with the reflux oil. On the other hand, a mechanism in which oil with a low bubble content flows out from the hole of the swirl flow chamber is required.

  In order to remove the bubbles of the return oil by adopting the bubble removing device having such a mechanism in the hydraulic oil tank of the hydraulic circuit, a tank structure change and a pump and a pump circuit for generating a swirling flow are required. In addition, since the hydraulic oil containing a large amount of bubbles after separation is sent back to the swirl flow chamber together with the return oil by the pump, the bubble content of the return oil increases, and in a small capacity hydraulic oil tank with a small amount of oil used Also, there is a problem that is difficult to adopt from the viewpoint of bubble removal efficiency.

  The object of the present invention is to make the flow of return oil returning to the hydraulic oil tank into a swirl flow without using a pump, so that bubbles can be separated by centrifugal force without changing the structure of the conventional hydraulic oil tank. Equipped with a new bubble eliminator that can be efficiently and installed in the tank, does not require a large space, and can sufficiently separate and remove bubbles even in small hydraulic oil tanks. It is to provide a hydraulic oil tank.

  The bubble remover of the present invention according to the above object has a small-diameter inner tube having a number of outflow holes from the central portion to the periphery of the lower tube body at the center of the outer tube having a number of outflow holes around the tube body except for the lower portion. Installed to form a flow path between tubes, a gas-liquid separation tube with a flow port provided at the lower end of the tube of the outer tube, and the center of the top plate that closes the upper end with a cylindrical shape larger in diameter than the outer tube The gas-liquid separation tube has an insertion hole in its part, and a main body that is partitioned into an upper chamber and a lower chamber having an opening on one side by a floor plate. A lower end is inserted, the flow port is adjacent to the opening, the boundary between the flow port and the opening is blocked by a partition piece, and the upper chamber is formed as a swirling flow path communicating with the flow path. An inflow port is provided in the.

  Further, the hydraulic oil tank of the present invention is configured such that the bubble remover is erected in the tank by connecting the inlet of the lower chamber of the main body to the return port of the return oil in the tank, and the hydraulic oil in the tank The height of the surface is limited to a height at which the upper end of the gas-liquid separation tube protrudes from the liquid surface and gas is discharged from the inner tube onto the liquid surface.

  In the above configuration, a bubble remover is composed of a double-tube gas-liquid separation tube composed of an outer tube and an inner tube having a number of outflow holes around the tube body, and a main body in which the gas-liquid separation tube is inserted into the top plate. Since the upper chamber formed in the section of the main body is formed in the swirling flow path by inserting the lower end of the gas-liquid separation pipe, a swirling flow is generated only by the momentum of the return oil flowing down to the hydraulic oil tank, and centrifugal Since the bubbles can be separated by force by the inner tube, a special means for generating a swirling flow such as a pump is not necessary.

  The swirl flow path is also formed by inserting the lower end of the gas-liquid separation pipe provided with a circulation port into the upper chamber in the main body partitioned by the floor plate, and the circulation port adjacent to the opening on one side of the upper chamber. The boundary between the opening and the opening can be formed simply by blocking the boundary with a partition piece, and the swirling flow is guided to the flow path of the gas-liquid separation pipe by the partition piece. The air bubbles can be separated efficiently by the inner tube due to the centrifugal force and the difference in specific gravity.

  Also, in the hydraulic oil tank, it is only necessary to install a bubble remover in the tank and to project the upper end of the gas-liquid separation pipe above the hydraulic oil level. Therefore, even in a small-volume hydraulic oil tank, separation and removal of bubbles from the return oil can be performed efficiently.

  In the figure, reference numeral 1 denotes a gas-liquid separation tube. An inner tube 12 having a diameter (for example, 22 mm) smaller than the tube diameter (for example, 80 mm) of the outer tube is installed at the center of the outer tube 11 having a required length (for example, 365 mm). It consists of a double tube formed between the tubes in the flow path 13. A large number of hydraulic oil outflow holes 14, 14 are formed in parallel in the longitudinal direction around the tubular body except for the upper and lower portions of the outer tube 11, and a part of the side wall is cut out at the lower end of the tubular body. The distribution port 15 and a partitioning piece 16 formed by a section at the edge of the distribution port are provided.

  In addition, a large number of outflow holes 17 and 17 through which bubbles flow out into the tube are formed in parallel in the longitudinal direction around the tube body from the center to the lower end of the inner tube 12. The outflow hole 17 is a hole having a smaller diameter (for example, 3 mm) than the diameter (for example, 14 mm) of the outflow hole 14 of the outer tube 11.

  Reference numeral 2 denotes a cylindrical body (for example, a diameter of 125 mm and a height of 105 mm) having a larger diameter than the outer tube 11, and has an insertion hole 22 for the gas-liquid separation tube 1 in the center of the top plate 21 that closes the upper end. The interior is divided into an upper chamber 25 and a lower chamber 26 having an opening 24 on one side by a floor plate 23 cut out on one side, and an inlet 28 is provided in a bottom plate 27 of the lower chamber 26 that closes the lower end. Although not shown in the figure, the inlet 28 may be provided on the side surface of the lower chamber 26.

  In the upper chamber 25 of the main body 2, the lower end portion of the gas-liquid separation tube 1 inserted into the top plate 21 (for example, 50 mm) is located adjacent to the opening 24 and the circulation port 15 The boundary of the opening 24 is blocked by the partition piece 16, and the upper chamber 25 is formed in a return oil swirl flow path communicating with the flow path 13.

  The compartment of the upper and lower chambers in the main body by the floor plate 23 is in the state where the floor plate 23 is previously brought into contact with the lower end of the gas-liquid separation tube 1 to weld the outer tube 11 and the inner tube 12 and the floor plate 23 is attached. The separation tube 1 can be inserted into the insertion hole 22 of the top plate 21 from the inside of the main body 2. The abutment of the floor plate 23 is performed by overlapping the partition piece 16 on the notch edge 23 ′ of the floor plate 27, and after inserting the partition piece 16 at the one edge of the flow port to the top plate 21, the outer tube 11 is inserted at that position. The top plate 21 is welded, and the floor plate 23 is welded to the peripheral wall of the main body 2. Thereby, the division of the upper chamber 25 and the lower chamber 26 and the opening 24 are formed by the floor plate 23, and the boundary between the circulation port 15 and the opening 24 is blocked by the partition piece 16. After the floor plate 23 is welded, a bottom plate 27 provided with a connection port 28 is brought into contact with the lower end of the main body and welded.

  FIG. 4 shows a hydraulic oil tank 3 of an injection molding machine. A reflux port 32 is provided on the tank bottom plate 31 upward together with a supply / outlet 33, and the bubble remover is provided in the lower chamber of the main body 2 at the reflux port 32. 26 connecting ports 28 are fitted to stand in the tank. Further, the height of the liquid level L in the tank of the hydraulic oil 4 is such that the upper end of the gas-liquid separation pipe 1 protrudes from the liquid level L into the space 35 between the liquid level L and the tank ceiling 34, and from the inner pipe 12. The height at which the separated gas is discharged into the space 35 is limited. The released gas is naturally exhausted to the outside through an exhaust hole 36 formed in the upper corner of the tank 3.

  In the hydraulic oil tank 3 having the above-described configuration, oil discharged from a cylinder, an oil motor, and the like and then returned through the pipeline flows from the reflux port 32 into the bubble remover. In the bubble remover, the lower chamber 26 and the upper chamber 25 of the main body 2 communicate with each other through the opening 24, and the upper chamber 25 and the flow path 13 inside the bubble separation tube 1 communicate with each other through the flow port 15. The return oil 26 flows into the flow path 13 through the upper chamber 25 and flows out from the outflow hole 14 of the outer pipe 11 into the tank.

  In this flow process, since the upper chamber 25 is formed in a swirling flow path having the inner wall and the outer wall of the main body 2 and the outer tube 11, the return oil flows so as to swirl along the inner and outer walls. The momentum of the swirl flow is proportional to the flow rate of the return oil flowing down, but the swirl flow moves upward of the flow path 13 due to the circular cross section of the flow path 13 ahead of the upper chamber 25. . When the return oil flows while swirling, centrifugal force is generated, and bubbles are gathered to the inner tube 12 side of the swirl center due to the difference in specific gravity, and the bubbles decrease toward the outside of the swirling flow.

  Since the inner pipe 12 has small-diameter outflow holes 17, 17 formed around the upper pipe body from the lower end, the collected bubbles flow into the inner tube 12 through the outflow holes 17, 17 and return. It is separated from the oil, further rises as a gas in the pipe, and is discharged from the opening at the upper end of the inner pipe 12 to the tank internal space 35 on the liquid level L. This separation / removal occurs until the swirl flow is eliminated, whereby the bubbles are separated / removed efficiently. The defoamed return oil flows out into the tank from the circulation holes 14 and 14 of the outer tube 11 by centrifugal force, and is stored in the tank as the hydraulic oil 4 containing almost no bubbles. This makes it possible to efficiently separate and remove bubbles even in a small capacity tank due to a decrease in the amount of oil used.

It is a vertical front view of the bubble remover of the hydraulic oil concerning this invention. It is the sectional view on the AA line in FIG. It is a front view of the bubble remover which shows the main body vertically. It is a vertical front view of the hydraulic oil tank concerning this invention. It is a hydraulic circuit diagram of an injection molding machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas-liquid separation pipe 2 Cylindrical main body 3 Hydraulic oil tank 4 Hydraulic oil 11 Outer pipe 12 Inner pipe 13 Flow path 14 Hydraulic oil outflow hole 15 Distribution port 16 Partition piece 17 Bubble outflow hole 21 Top plate 23 Floor plate 24 Opening Section 25 Upper chamber 26 Lower chamber 27 Bottom plate 28 Connecting port 31 Tank bottom plate 32 Return port

Claims (2)

A small-diameter inner tube with a number of outflow holes is installed around the lower tube from the center to form a flow path between the tubes at the center of the outer tube with a number of outflow holes around the tube excluding the lower part. And a gas-liquid separation pipe provided with a distribution port at the lower end of the outer pipe,
The upper part of the top plate that closes the upper end with a cylindrical shape larger in diameter than the outer tube has an insertion hole for the gas-liquid separation tube, and the interior is divided into an upper chamber and a lower chamber that have an opening on one side by a floor plate The main body,
The lower end of the gas-liquid separation tube is inserted into the upper chamber of the main body, the flow port is adjacent to the opening, the boundary between the flow port and the opening is blocked by a partition piece, and the upper chamber is connected to the flow path. A bubble remover for hydraulic oil of an injection molding machine, characterized in that it is formed in a swirling flow path communicating with the inlet and provided with an inlet in a lower chamber.   The bubble remover according to claim 1 is erected in the tank by connecting the inlet of the lower chamber of the main body to the return oil return port in the tank, and the level of the liquid level in the tank of the hydraulic oil A hydraulic oil tank for an injection molding machine, characterized in that the upper end of the gas-liquid separation pipe protrudes from the liquid surface and is restricted to a height at which gas is discharged from the inner pipe onto the liquid surface.

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