JPS6012254A - High pressure gas type mold material compacting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a high-pressure container for high-pressure gas forming a pre-pressurization chamber;
a molding chamber provided under the container and comprising a molding box, a filling frame, and a mold plate having a mold on which mold material before compaction is loosely deposited and closing the bottom surface of the molding box;
This invention relates to a device for consolidating mold material with high-pressure gas, comprising a pre-pressurizing chamber and a valve with a large opening cross-sectional area provided between a molding chamber and a molding chamber.

[Background Art] The method and apparatus of the above configuration are disclosed in the applicant's West German patent application No. P 324H, the content of which is related to the subject matter of the present application.
It is described in No. 51. In the case of the above-mentioned application, the loosely deposited inner mold sand on the master and the master plate is consolidated solely by high-pressure gas acting on the free surface of the mold material, without the use of auxiliary means (for example pressing equipment). In this method, in order to obtain uniform and sufficient mold hardness, it is necessary to rapidly increase the pressure in the molding chamber. Consolidation takes place in this case by impact exchange between the mold material particles, by damping of the mold material particles by the master and the master plate, and by auxiliary flow effects. The large pressure gradient in the molding chamber, ie the rapid pressure build-up, depends primarily on the initial pressure (prepressure) in the prepressurization chamber. That is, the higher this initial pressure, the more
Although large pressure gradients are obtained, the equipment costs required to create this initial pressure are also high. If the prepressure (e.g. the pressure of the factory's high-pressure air system) is of a reasonable magnitude, the valve between the high-pressure vessel and the molding chamber needs to be opened and closed in a few ms to obtain a large pressure gradient. .

For this purpose, the above-mentioned West German patent application No. P 3243951
A valve with a special structure as described in No. 1 is required.

〔assignment〕

Another parameter that is taken into account is the amount of gas acting on the free surface of the mold material, the ratio of this gas amount to the amount of mold material having to be at a predetermined value.

For example, for a molded box of normal dimensions, the gas flow rate is 50k
g/'s, and if the final pressure is about 8 bar, the pressurization rate in the molding chamber should be 300 bar/'s.
It must be larger than s. To obtain the required waste flow rate and A pressure rate, not only a valve that opens and closes quickly is required, but the free cross-sectional area must also be correspondingly large.
Must be. In order to satisfy the above conditions regarding a large valve cross section and rapid valve opening/closing, the mass of the opening/closing mechanism must be made as small as possible, even though the opening/closing mechanism is necessarily large in size. Therefore, the control of pressure gradient and gas flow rate is
Essentially, this has to be done by adjusting the prepressure. Therefore, the mold hardness t which directly depends on the above parameters
R adjustment also has to depend on front pressure. Such an operation is
Because of the short cycle time of the molding machine, and also because high pressure gas is generally stored in a tank with constant pressure,
In view of the fact that they are formed by an exothermic reaction of the combustion gas mixture, this is either not possible, or even if it were possible, the equipment costs would be correspondingly high.

An object of the present invention is to provide a device having the structure described at the beginning (for example, the patented M P 3
243951).

[Disclosure of the invention] This object is based on the present invention to provide a valve for use in consolidation,
- achieved by arranging a control valve which has a free opening cross-sectional area larger than the free cross-sectional area of the opening of said valve and which can be adjusted to a predetermined control cross-sectional area by a control mechanism before the opening movement of the opening/closing mechanism is started; Ru. The control valve is preferably arranged between the prepressurization chamber and the consolidation valve, but it can also be arranged after the consolidation valve.

It is also conceivable to configure the valve body between the high-pressure container and the molding chamber as a control valve and to control the flow cross-section accordingly, but such a configuration would require that the valve meet the requirements mentioned at the beginning. Impossible in practice since it is imposed. Therefore, the present invention takes a different approach. This means that the valve is provided with a further control valve whose control cross section can be preadjusted in order to adjust the gas flow rate at a given prepressure. In this case, there is no need to change the original consolidation valve. Therefore, the mold hardness that can be achieved by pressure relief can be adjusted within a wide range. In order to obtain the maximum mold hardness when the controlled cross-sectional area is completely opened, or, if the mold hardness is specified, to ensure that the mold material is sufficiently compacted even if the molding box is large in size. , the free opening cross-sectional area of the control valve should be as large as possible than the free opening cross-sectional area of the consolidation valve.

In a preferred embodiment, the control valve can be closed by the control am after the opening of the opening/closing mechanism.

Thus, in addition to its original control function, the control valve also performs a safety function. That is, after compaction and evacuation of the molding chamber and also during lowering of the molding chamber, no or only a small escape of high-pressure gas occurs. This condition is important. because,
This is because after the consolidation operation, the consolidated mold is removed and the molding box and filling frame are refilled with molding material, so that the high-pressure container and valve are separated from the molding box and filling frame. In this case, the control valve can be actuated such that the compression valve is in the closed state and then reaches the open position.

If the valve opening is provided at the bottom of the high-pressure vessel, according to one embodiment, a flow chamber for the high-pressure gas, which is connected to the prepressurization chamber via a control valve and is open only in the direction of the valve opening, is placed above the bottom. Provided for. This flow chamber is used to introduce high pressure gas from the prepressurization chamber of the high pressure vessel to the valve opening.

The blow chamber can, for example, be provided with a wall with a number of openings extending vertically upwards, surrounding the valve opening and forming the free cross section of the control valve. In this case, the control mechanism is
Guide along the wall and provide a corresponding number of openings. In this embodiment, in particular, the drive mechanism for the pressure-tight valve can be provided within the high-pressure vessel.

Preferably, the vertical wall openings of the flow chamber and the openings of the control mechanism are configured as vertical control slits, the degree of overlap of which determines the gas flow rate.

In order to maximize the free cross-sectional area of the consolidation valve, the free cross-section of the consolidation valve generally corresponds to the contour of the forming box and filling frame. That is, the contour of the valve opening is woodenly rectangular. In this case, according to one embodiment of the invention, control slits are provided in at least two walls of the flow chamber standing on each side of the rectangle, and the control mechanism is constructed as a displaceable plate with slints.

Alternatively, the vertical wall of the flow chamber surrounding the valve opening can be configured circularly and provided with equally spaced control slits in said wall. In this case, the control mechanism is configured as a rotatable slitted ring.

[BEST MODE FOR CARRYING OUT THE INVENTION 1] The present invention will be described in detail below with reference to illustrated embodiments.

In the drawings, only the parts of the compaction device of the mold forming machine that are necessary for understanding the present invention are shown. The machine cradle, the lifting device for the molding box and the filling frame, the device for pushing the finished mold out of the molding box, etc. are not shown. Furthermore, the master mounting device and the mold hard loading device are also not shown, as they are well known in the art of mold forming machines.

A molding box 3 rests on a molding plate 1 with a molding material 2, on which a filling frame 4 rests. A high pressure container 5 is provided above the molding chamber. In the illustrated embodiment, the high-pressure vessel 5 receives via a connection 8 high-pressure air coming from a pressure accumulator or high-pressure air coming from the factory's high-pressure air system (if the pre-pressure is low).

The bottom 7 of the high-pressure vessel is constructed as a stationary plate with a number of holes 8 arranged in the shape of a rotor in the area above the molding chamber. On the underside of the bottom part 7 is flanged a frame 9 to which a discharge conduit with a valve 10 is connected. A high-pressure vessel 5 with a frame 8 attached and a prototype play with a prototype 2) 1
, the molding box 3 and the filling frame 4 can be moved relative to each other in order to fill the molding chamber with mold material. Both structural groups are consolidated and pressed to bring the interfaces into close contact before the consolidation operation.

The bottom part 7 or the bottom area with holes 8 cooperates with an opening/closing mechanism in the form of a rigid plate 11, which is also provided with a number of coaxial holes 12. As can be seen from the left half of the drawing, the holes 8 in the bottom part 7 and the holes 12 in the valve plate 12 are offset from each other and therefore do not coincide in the closed position.

The valve plate 11 is attached to a guide rod 14 which is moved from the open position of the valve plate (shown in the right half of the drawing) to the closed position by an actuating piston 15 sliding along the guide rod. position (shown in the left half of the drawing).

A cylinder 16 fixed in the high-pressure vessel 5 for the working piston 15 is provided with a damping cylinder 17 cooperating with a top beam 18 fixed on the guide rod 14 . When the working piston 15 is raised, the upper surface of said working piston acts on said top beam 18. The guide rod 14 is furthermore provided with a clamping device 18 having a clamping element 2o which is movable axially in a housing 21 supported on the bottom and a further clamping element 22 on the guide rod. The clamping member may be a wedge or the like.

The above-mentioned pressure-tight valve is equipped with an adjustable control valve. In the illustrated embodiment, the opening/closing mechanism for the consolidation valve is opened on the molding chamber side, so the control valve is provided in front of the consolidation valve.

The bottom 7 of the high pressure vessel 5 is provided with a support member 23 which forms a flow chamber 23 between the bottom 7 and itself. The circumference of the flow chamber is formed by a vertical wall 28 rising along the outer surface of the consolidation valve 8.11.12. This wall can be configured circularly or rectangularly and has a coaxial control slit 25 surrounded from the outside by a control mechanism 2θ which also has a slit 27. The control mechanism can consist of a displaceable plate or ring section, depending on the shape of the vertical wall 28.

The operating mode of the device will be explained below.

In the illustrated closed position of the valve, the control slit 25 of the support member 23 is also closed by the control mechanism 28 and the high-pressure vessel 5 is filled with high-pressure gas via the connection 6.

Since the clamping device 18 is in the clamping position, the valve plate 11
is pressed against the bottom 7 and sealed. The molding box 3 and the filling frame 4 are loosely filled with molding material (for example molding sand). To start the opening operation, first displace the control mechanism 25 so that the slit 27 is aligned with the support member 23.
completely or partially coincides with the control slit 25 (see right half of the figure), thus delivering high pressure gas to the flow chamber 24. The mechanical safety locking mechanism 28 is then withdrawn and the actuating piston 15 is slid downward along the guide rod 14 with the clamping device 18 blocked. The clamping device 18 is then opened hydraulically, thus opening the guide rod 14 and the valve plate 11. The high pressure gas that has reached the valve plate 11 through the hole 8
as a result of which the high pressure gas
and into the forming guide via the edge of the valve plate. The amount of gas flowing, that is, the amount of gas acting on the mold material, is determined by the control cross-sectional area (degree of overlap of the control slits 25° and 27) set by the control mechanism 26.

During the opening operation, the guide rod 14 is damped by the damper 17 when it abuts the top beam 18 . The valve plate 11 reaches the position shown in the right half of the drawing. During this time, the molding sand
While being accelerated, it is braked and consolidated by the master plate 1 and the master mold 2. After the opening operation is completed, the control mechanism 2B is returned to the closed position for safety. The next filling operation can then be started, in which case
Moreover, high pressure gas does not flow. The guide rod 14 together with the valve plate 11 is then raised by the actuating piston 15 via the top beam 18 and held in the closed position by the clamping device (left half of the drawing). Safety locking mechanism 28 is inserted. During this time.

The high pressure gas still remaining in the molding chamber is released via valve 10.

[Brief explanation of the drawing]

The corrugated drawing is a longitudinal sectional view of the consolidation unit. l... Prototype plate, 2... Prototype, 3... Molding box. 4... Filling frame, 5... High pressure container (pre-pressurization chamber)
8... Valve opening, 11... Opening/closing mechanism. 25, 26: 27...Control valve applicant: BMD Badische Maschinenfabrik Deurlach GmbH Attorney Patent attorney: Asamichi Kato

Claims (1)

[Claims] 1) A high-pressure container for high-pressure gas forming a pre-pressurization chamber, a molding box, a filling frame, and a molding box provided below the container.
A molding chamber consisting of a master mold on which mold material is loosely deposited before compaction and a master plate that closes the bottom surface of the molding box, and an opening/closing mechanism that opens within a range of mS and is provided between the pre-pressurizing chamber and the molding chamber. In a device that piezoelectricizes mold material with high-pressure gas, the valve has a valve opening (8
), and is provided with a control valve (25, 26, 27,) that can be adjusted by the control mechanism (26) before the opening operation of the opening/closing mechanism (11). A device featuring: 2) Device according to claim 1, characterized in that the control valve (25, 26, 27) is provided between the prepressurization chamber (5) and the valve opening (8). 3) The device according to claim 1 or 2, characterized in that the control valves (25, 27) can be closed by the control mechanism (26) after the opening/closing mechanism (11) has opened. 4) When the valve opening (8) is provided at the bottom (7) of the high pressure vessel (5), the high pressure vessel (5) is opened via the control valve (25, 27).
) A high-pressure gas flow chamber (24) connected to the valve opening (8) and opened only in the direction of the valve opening (8) is provided above the bottom part. - The device according to. 5) a flow chamber (24) surrounds the valve opening (8);
The control mechanism (26) has a wall (29) extending vertically upwards and provided with a number of openings forming the free cross section of the control valve.
It is guided along the wall (29) and has a corresponding number of openings (
27). The device according to claim 4, characterized in that it comprises: 6) The opening in the vertical wall (29) of the flow chamber (24) and the opening in the control mechanism (26) are connected to the control slit (25).
, 27). 7) If the valve opening (8) is rectangular in nature, control slits (2
6. The device according to claim 4, wherein the control mechanism (2B) is a displaceable plate with slits. 8) The vertical wall (29) of the flow chamber (24) circularly surrounds the valve opening and includes equally spaced control slits (2).
7), and the control mechanism (28) is constructed as a rotatable slitted ring. 9) The device according to claim 4 or 5, characterized in that the control valve is configured as a bell-shaped body that surrounds the valve used for compaction and is movable up and down and whose lifting stroke can be adjusted in advance.