EP1728564A1 - Vibration generator with an operating piston that is slidingly supported between pressure chambers - Google Patents

Abstract

The generator (1) includes a control device having a reciprocating control piston (3) set within a reciprocating working piston (2) set inside a housing (20). The working piston divides the housing interior into two pressure chambers (11,12). The two pressure chambers alternately receive working fluid during the reciprocating of the working piston. An independent claim is also included for a construction apparatus.

Description

The invention relates to a vibration generator according to the preamble of claim 1 with a working piston and a control device with a control piston which is slidably mounted within the working piston, and a construction device with a vibration generator according to the preamble of claim 11.

Such vibrators have a variety of applications, such as where bulk goods are to be compacted, e.g. in the packaging industry or also in the production and compaction of castings made of concrete or similar material. Also in the civil engineering for the creation of Erdbohrungen or soil compaction a variety of applications are given.

In devices used for soil compaction, two rotating unbalance elements are arranged side by side. An imbalance element is connected to a drive unit, while the second is driven by a transmission. The phase position of the imbalances on the respective unbalanced shafts is adjustable, whereby a propulsion movement of a vibrating plate is infinitely adjustable.

The DE 195 23 030 C2 discloses a vibration exciter with a housing in which a movably mounted exciter mass for the vibration generation and a consisting of a piston-cylinder unit drive for the exciter mass are arranged. In this case, the exciter mass is rigidly coupled to a hydraulically driven drive piston of the piston-cylinder unit and against the action of variably adjustable in the spring detection spring and damping means back and forth linearly.

Also known are vibrators that are operated with a pressure medium.

DT 24 45 215 A1 describes a vibrator with a cylinder slidably seated in a cylinder, wherein the cylinder has an inlet opening and two outlet openings, which are located in the wall of the cylinder. The cylinder or piston is milled, the sleeve forming cooling channels for the flow of driving medium.

The DE 39 15 773 A1 discloses a piston vibrator from a housing having a cylindrical bore, a laterally guided to the bore air port and a longitudinally displaceable piston in the bore. The cylindrical bore extends in the axial height of the air connection asymmetric to the outer wall surface of the housing.

From the DE 17 68 865 U1 For example, a vibrator is known in which a constant amplitude drive piston is mechanically reciprocated within a housing. Via an air column, the drive piston transmits, as an excitation mass, a vibratory motion to a working piston which is freely movable in the same cylindrical housing and which is coupled to the drive piston via an air column.

On the opposite side of the air piston of the working piston, a further air column is provided, wherein the volume of the two air columns is adjustable, so that the vibrations of the working piston and its amplitude over the air volume of the air columns is variably adjustable.

However, air and other compressible media often can not produce sufficiently high power levels. For this reason, there is a need to make vibration generator with the same outer dimensions more efficient or to make more compact while maintaining performance. This can be achieved, for example, by using incompressible media as the working fluid. However, very high demands are often placed on the complexity of the structure.

The invention has for its object to provide a vibration generator, which is also driven reliably with incompressible media in a simple structure.

This object is achieved by a vibration generator according to claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

By the features according to the invention, a vibration generator is provided which can be operated with an incompressible medium, and thereby can transmit much greater power compared to pneumatic systems with the same size. Due to the simple mechanical design of the control device a trouble-free reliable operation is guaranteed. Thus, time-consuming and costly maintenance, as they often occur in complex electronic control systems omitted. The production of the vibration generator according to the invention is economically feasible, since only mechanical elements are used.

In addition, the transmission of the vibration takes place exclusively by the oscillating movement of the housing. So there is no direct contact between the working piston and the housing wall. Such impact movements lead to loud noise emissions, increase the wear and shorten the life of the device.

The invention thus provides a vibration generator which generates a low level of noise during operation and the individual components have a relatively long service life.

As printing fluids, all conventional gases and liquids can be used. A particularly high performance is achieved in particular with incompressible liquids, such as hydraulic oil.

The area ratios of the working and control pistons are chosen so that the acceleration forces on the active mass in both directions of movement are equal.

For a simple production, it makes sense to design the housing cylindrical. As a result, the manufacturing costs can be kept low and wear processes can be minimized via the more uniform force distribution.

It is expedient to store the working piston completely in the cylindrical housing and not lead out of the housing. As a result, wear-prone seals can be avoided.

Preferably, the working piston is mounted concentrically in the cylindrical housing. This allows a simple production for a uniform mechanical load during operation.

It is advantageous if the control piston is displaceable between two control piston reversal points, which are predetermined by two abutment regions on the housing. This stop areas can also be formed above and made of a particularly impact-resistant material. The shift between only two reversal points allows simple mechanical movements and ensures reliable control. The housing can also be closed at the end by cover. In this case, the stop areas can be formed by a design of the lid inside, which influence the end position of the control piston.

Preferably, the stop areas are adjustable. By means of the adjustable stop areas, the distance traveled by the control piston and thus the time interval per stroke period of the control piston can be varied. Thus, the oscillation frequency of the oscillation can be easily adjusted according to the particular application. An adjustment during operation is also conceivable, so that the work process does not have to be interrupted. The adjustable stop areas can be designed in the form of setscrews or adjusting stops, which can be adjusted mechanically or hydraulically from the outside.

In a further embodiment of the vibration generator according to the invention, the working piston is displaceable between two working piston reversal points and the control piston designed so that this reaches its control piston reversal point a defined period of time before the working piston his working piston reversal point on the respective Page reached. As a result, it can be ensured that the working piston does not strike against the housing, whereby, on the one hand, disturbing noises are avoided and, on the other hand, the mechanical wear is reduced.

This can preferably be achieved in that the stroke length of the control piston is as large as that of the working piston. A shortening of the stroke length of the control piston can be realized both by a longer extension of the control piston relative to the working piston or by projecting from the Gehäuseinnenwandung stop areas.

Suitably, the housing has a fluid flow for supplying a pressurized fluid and a fluid return for discharging a pressurized fluid. These fluid advances or returns can be formed for example as holes in the housing wall. Due to the separate arrangement of fluid flow / return, the pressure fluid can be added or removed in a defined and easily controllable manner in the designated areas.

It is advantageous if in the working piston in addition to a main supply line which connects the fluid flow with a flow control chamber, two flow distribution lines are provided, which connect the flow control chamber on the one hand with the first pressure chamber and on the other hand with the second pressure chamber. The main supply line and the two flow distribution lines can be designed as bores within the working piston. The flow control chamber may be formed by the end regions of the main flow line with the distribution lines. This makes it possible in a simple manner, the two pressure chambers to provide a pressure fluid in particular alternately and separately from each other and to ensure a hydraulic independence of the two pressure chambers. For optimal supply of the pressure fluid in the main flow line, a radially circumferential recess for receiving the pressure fluid can be provided in the outer region of the working piston.

It is further preferred if in the working piston in addition to a main return line, which connects the fluid return to a return control chamber, two return distribution lines are provided which connect the return control chamber on the one hand with the first pressure chamber and on the other hand with the second pressure chamber.

Analogous to the flow system, the main return line and the two return distribution lines can be designed as bores within the working piston. The return control chamber can thereby be formed by end regions of the main return line with the two distribution lines. Thus, it is easily possible to supply the two pressure chambers with a pressure fluid, in particular alternately and separately from each other and to ensure a hydraulic independence of the two pressure chambers.

For optimal removal of the pressure fluid in the main return line may be provided in the outer region of the working piston, a radially circumferential recess for receiving the pressurized fluid, which also serves to receive the fluid from the flow.

In a particularly preferred embodiment of the device according to the invention, the control piston on control areas through which the pressurized fluid from the flow control chamber either to a flow distribution line or the other flow distribution line is conductive. By means of the control regions can be passed through a simple displacement of the control piston relative to the working piston, the pressure fluid defined in one of the two pressure chambers, or shut off the supply of fluid.

Analogously, the control piston further control areas through which the pressurized fluid from one of the two pressure chambers in the return control chamber via one of the two return distribution lines can be conducted. Thus, by the mechanical displacement of the control piston and a defined discharge of the pressurized fluid from one of the two pressure chambers in the return possible. For a simple production, it is advantageous to design the control areas as control edges.

Suitably, the control piston is mounted centrally in the working piston. This storage ensures optimum power distribution, which ensures good efficiency. Furthermore, such storage can reduce wear processes and thereby extend the life of the device. This eliminates costly repair and maintenance intervals. In addition, a central storage and manufacturing technology is easy to implement, whereby the manufacturing cost can be reduced.

It is advantageous if the control piston is designed to be longer than the working piston. Thereby, the time intervals per stroke of the control piston become shorter than that of the working piston. The control piston thus reaches its reversal point earlier than the working piston and can therefore already initiate the reversal of the flow direction of the pressure fluid, when the working piston has not yet reached the housing inner wall. A stop of the working piston on the housing wall is thus prevented and avoided in this way disturbing impact noise and wear effects. Of course, it is also possible to shorten the path intervals of the control piston relative to the working piston by projecting from the Gehäuseinnenwandung stop areas, which can only contact the control piston.

The vibration generator according to the invention is provided according to the invention in a construction device according to the patent claim 11.

The construction equipment may in particular be a drilling device or a vibration bear for introducing piles, planks etc. into the ground.

When drilling, the drilling progress can be improved if the drilling action is assisted by an oscillating movement of the drilling tool. As a result, the time required to create the hole can be significantly reduced and the economy can be increased. Especially in view of the ever-increasing cost pressure in the construction sector, the competitiveness of the company is improved in this way. With a construction device based on the vibration generator according to the invention, which is characterized by non-striking working elements, the operating personnel and the environment is less burdened due to the lower noise. Particularly in the construction industry, the load on the material due to massive mechanical forces, hard soil material and damp weather is extremely high, so that the low wear of the construction equipment according to the invention has a positive effect on the service life and lowers the operating costs.

Moreover, since the device of the invention can operate on the basis of a hydraulic system with incompressible fluid, the performances to be achieved are higher in comparison with pneumatic systems based on compressible fluids. Therefore, the vibration generator according to the invention can also be advantageously used in a Vibrationsbär or other equipment for tillage.

The invention will be further explained with reference to an embodiment, which are shown schematically in the drawings.

Fig. 1

eine Querschnittsansicht des erfindungsgemäßen Schwingungserzeugers;

Fig. 2 bis 7

Querschnittsansichten des erfindungsgemäßen Schwingungserzeugers in einzelnen Schritten eines Schwingungszyklus.

Show it:

Fig. 1

a cross-sectional view of the vibration generator according to the invention;

Fig. 2 to 7

Cross-sectional views of the vibrator according to the invention in individual steps of a vibration cycle.

As shown in Fig. 1, the vibration generator 1 comprises a housing 20, a concentrically mounted therein linearly displaceable Arbbeitskolben 2 and a concentric in the working piston 2 linearly displaceable control piston third

The housing 20 comprises a housing jacket 27 which has bores for the fluid flow 6 and the fluid return 17, as well as a left cover 4 and a right cover 5. These are provided with a first stop region 21 and a second stop region 22, which end regions of the control piston 3 define.

The working piston 2 forms with the housing 20, a first and a second pressure chamber 11, 12. On the outer wall of the cylindrically shaped working piston radially circumferential recesses 25, 26 are provided for guiding the pressurized fluid from the fluid flow 6 and in the fluid return 17. Within the working piston 2 is a conduit system consisting of two independent channel arrangements. A channel arrangement is used to supply the pressurized fluid in one of the two pressure chambers 11, 12 and includes a main flow line 7 and a first and second flow distribution line 9, 10. The main flow line 7 opens into the flow receptacle 25 for receiving the pressurized fluid from the fluid flow 6. Die first flow distribution line 9 opens into the first pressure chamber 11, while the second flow distribution line 10 opens into the second pressure chamber 12. Together with the wall of the control piston 3, the outputs of the two flow distribution lines 9, 10 with the main flow line 7, the flow control chamber 8. The second line system serves to discharge the pressurized fluid from the pressure chambers 11, 12 and includes a main return line 16 and two return Distribution lines 13, 14. The first return distribution line 13 opens into the first pressure chamber 11, while the second return distribution line 14 opens into the second pressure chamber 12. The main return line 16 is connected via the return intake 26 with the fluid return 17 to the outflow of the pressurized fluid.

The control piston 3 has a first control region 23 and a second control region 24, which are formed as control edges. By moving the control piston, the first control section 23 opens or blocks the main supply line and the flow distribution lines 9, 10, while the second control section 29 connects the main return line 16 to one of the two return distribution lines 13, 14 by displacement.

The single step sequence of a vibration cycle is shown below.

As shown in Fig. 2, the pressure fluid flows through the fluid flow 6 and the main flow line 7 in the flow control chamber 8, whereby the control piston 3 is pushed by the building up in the flow control chamber 8 pressure within the working piston 2 to the right and in the supply control chamber 8 strikes right. The pressure of the pressure fluid builds up on the first flow distribution line 9 in the first pressure chamber 11 and pushes the piston 2 to the right. At the same time, the pressure fluid in the second pressure chamber 12 passes via the second return distribution line 14 into the return control chamber 15 and from there via the main return line into the fluid return 17.

In Fig. 3, the working piston 2 moves to the right, so that the control piston 3 abuts on the right cover 5 at the second stopper portion 22.

In Fig. 4, the control piston 3 remains in its position, while the working piston 2 moves due to the pressurization to the middle position and from there because of its inertia further to the right. As a result, the relative position of the control piston 3 to the working piston 2 changes. The control piston 3 reaches the center position with respect to the working piston 2, in which neither the first pressure chamber 11 has a connection to the fluid flow 6 nor the second pressure chamber 12 has a connection to the fluid return 17. In this position, the working piston is moved by its inertia a little further to the right, thereby changing the pressurization of the control piston. The control piston is moved to the left again; As a result, the pressure conditions on the working piston change and the direction of movement of the working piston is reversed.

As shown in Fig. 5, the pressurized fluid passes through the rightward movement of the working piston 2 in the right region of the flow control chamber 8, whereby the control piston 3 is pressed by the building up in the flow control chamber 8 pressure within the working piston 2 to the left and in the flow control chamber 8 abuts on the left. Via the second flow distribution line 10, the pressure of the pressure fluid in the second pressure chamber 12 builds up and pushes the working piston 2 to the left. At the same time, the pressure fluid in the first pressure chamber 11 flows via the first return distribution line 13 into the return control chamber 15 and from there via the main return line 16 into the fluid return 17.

In Fig. 6, the working piston moves to the left, so that the control piston 3 abuts on the left cover 4 at the first stopper portion 21.

As shown in Fig. 7, the working piston 2 is pushed further to the left, while the control piston 3 remains in its position. As a result, the position of the control piston 3 relative to the working piston 2 changes. The control piston 3, relative to the working piston 2, again reaches the central position in which neither the second pressure chamber 12 has a connection to the fluid flow 6 nor the first pressure chamber 11 has a connection to the fluid return. In this position, a change of direction is initiated again. The cycle has thus once been run through and continues as described in Fig. 2.

The working piston 2 may be formed with a defined high mass, while the control piston 3 is substantially smaller and with significantly lower mass, such as by using a light metal, is formed.

Claims (11)

Vibration generator (1) with a working piston (2), which in a housing (20) between at least two pressure chambers (11, 12) is reciprocally mounted, wherein by means of a control device depending on the position of the working piston (2) a pressure fluid alternately into one of the pressure chambers (11, 12) can be conducted and the working piston (2) is displaceable in a reversing motion for generating vibrations,
characterized,
that the control device comprises a control piston (3) which is slidably mounted within the working piston (2). Vibration generator according to claim 1,
characterized,
in that the control piston (3) is displaceable between two control piston reversal points, which are predetermined by two stop regions (21, 22) on the housing (20). Vibration generator according to claim 2,
characterized,
that the abutment regions (21, 22) are adjustable. Vibration generator according to one of claims 1 to 3,
characterized,
that the working piston (2) is displaceable between two working piston reversal points, and
that the control piston (3) is designed such that it reaches its control piston reversal point a defined period of time before the working piston (2) reaches its working piston reversal point on the respective side. Vibration generator according to one of claims 1 to 4,
characterized,
in that the housing (20) has a fluid feed (6) for supplying a pressurized fluid and a fluid return (17) for discharging a pressurized fluid. Vibration generator according to one of claims 1 to 5,
characterized,
in that in the working piston (2) a main supply line (7), which connects the fluid flow (6) with a flow control chamber (8), also two flow distribution lines (9, 10) are provided, which the flow control chamber (8) on the one hand with the first pressure chamber (11) and on the other hand with the second pressure chamber (12) connect. Vibration generator according to one of claims 1 to 6,
characterized,
that in the working piston (2) a main return line (16) which connects the fluid return (17) with a return control chamber (15), also two return distribution lines (13, 14) are provided, which the return control chamber (15) on the one hand the first pressure chamber (11) and on the other hand connect to the second pressure chamber (12). Vibration generator according to one of claims 1 to 7,
characterized,
that the control piston (3) has control areas (23, 24) through which the pressurized fluid from the supply control chamber (8) either to a supply distributing line (9) or to the other flow distributing line (10) can be conducted. Vibration generator according to one of claims 1 to 8,
characterized,
that the control piston (3) is mounted centrally in the working piston (2). Vibration generator according to one of claims 1 to 9,
characterized,
that the control piston (3) is designed as the working piston (3) is longer. Construction equipment, in particular drill or vibration bear,
characterized,
in that at least one vibration generator (1) according to one of Claims 1 to 10 is provided.

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