EP0329208B1 - Hydraulically driven high-pressure cleaner - Google Patents

Description

The invention relates to a hydraulically driven high-pressure cleaner with at least three pistons loaded with hydraulic oil on one side, which on the other side act in a continuous manner on a second liquid to be displaced, with a synchronizing rod and a rotating device having a swash ring, the rotating device being one Control drives.

US-A-3 133 503 shows an oil hydraulic pressure booster with a piston, a synchronizing rod, a rotator and a control and which further discloses that the control is driven by the rotator, the rotation of which is caused by the axial movement of the pistons.

Furthermore, high-pressure cleaners are known which contain a plurality of hydraulic pistons which drive a control in the center and from there a multiplicity of water pistons which are connected to the hydraulic pistons. Since the use of external rubber seals to seal the pistons is required, one becomes large Installation diameter required. Since the control must be arranged in such cases between the oil-hydraulic and the water-loaded piston surface, the radially required installation space is very large, especially since it increases square with the radius; the longitudinal installation space is also increased as a multiplier of the stroke required as a result of the additional installation space, which leads overall to a large weight and volume of the machine. These problems become particularly clear when the synchronizing forces are determined, which arise, for example, from piston friction, sealing friction and other friction, such as, for example, from bearings and from hydraulic forces which are required to overcome the compression oil enclosed in the dead center in the cylinder. As a general empirical value, it has been found that the rotating device and its bearings and / or sliding parts have to be designed very large in relation to the piston and seal diameters, a further mechanical reinforcement being required in the case of alternating loads. In total, no generic devices have yet been produced in series, but only "conventional designs", ie devices with hydraulic motors, hydraulic control elements, couplings, water pumps, water-side control devices, mounting frames, covers etc., because the technical difficulties with previous, generic devices were too great .

The invention has for its object to provide a pressure washer that is extremely light and compact, yet reliable and which allows easy use with forklifts, tractors, construction machines, trucks with on-board hydraulics, concrete mixers, etc.

According to the invention, this object is achieved in that the rotating device has a perforated disk, that the synchronizing rod is arranged on each driving oil side and against the piston side of the hydraulically driven piston facing the displacing fluid, the synchronizing rod being positively and movably connected to the rotatably mounted perforated disk in the swashplate so that it drives the axial movement of the pistons in a rotary movement of the Swash rings is implemented, the control unit controlling the hydraulic oil to and from the pistons so that their axial movement is generated.

Advantageous embodiments of the invention are characterized by the features specified in claims 2 to 14.

As a result of this arrangement, the rotating device (9-12) and the control (22, 51) can be radially enlarged considerably and housed in a freely available space which is usefully formed by the common circumferential circle of all pistons, including their seals. As a result, you can in turn the piston-cylinder-seal arrangements are placed next to each other as possible, so that a large rotating device (9-12) and control (22, 51) can be freely designed in such a way that the high synchronization forces are absorbed reliably.

As a further result of the concept of the invention, the axial forces driving the rotating device (9-12) and control (22, 51) occur mainly as pulling forces only in one working direction, so that dangerous alternating forces are avoided and the machine life is thereby considerably increased.

As a further result, the machine can be arranged so compactly with all the internal parts so close together that all oil-hydraulic and water-side control elements can be accommodated so close together in the cylinder block (1) or valve block (50) that external piping, connecting pieces, assembly arrangements etc. are avoided in favor of a totally integrated design.

The overall result is that the machine according to the invention is so compact, light, and yet reliable that simple work with forklifts, agricultural tractors, construction machinery, trucks. With working hydraulics, concrete mixers etc. is possible as a small and handy implement.

Fig. 1

einen Längsschnitt durch einen erfindungsgemäßen Hochdruckreiniger;

Fig. 2

einen Schnitt längs der Linie II-II der Fig. 1;

Fig. 3

einen Längsschnitt einer alternativen Ausführung des Erfindungsgedankens;

Fig. 4

einen Gewichts- und Volumenvergleich einer konventionellen Maschine im Vergleich mit einem realisierten, erfindungsgemäßen, hydraulisch angetriebenen Hochdruckreiniger

Der in Fig. 1 gezeigte, erfindungsgemäße Hochdruckreiniger besteht aus einem Zylinderblock (1), in dem ölhydraulisch angetriebene Kolben (2) axial beweglich angeordnet sind. Drucköl (23) wird in die Einlaßöffnung (24) und über einen Verbindungskanal (25) zu einer Steuerung (22) geleitet, d.h. über deren Umfangskanal (26), eine Verbindungsbohrung (27) zur Druckniere (28) und von dort zu einer Steuerbohrung (29) und von dort in den Zylinderraum zwischen dem rechten Ende des Kolbens (2) und dem linken Ende der Synchronisierstange (6).The accompanying drawings illustrate the invention and show:

Fig. 1

a longitudinal section through a pressure washer according to the invention;

Fig. 2

a section along the line II-II of Fig. 1;

Fig. 3

a longitudinal section of an alternative embodiment of the inventive concept;

Fig. 4

a weight and volume comparison of a conventional machine in comparison with a realized, hydraulically driven high-pressure cleaner according to the invention

The high-pressure cleaner according to the invention shown in FIG. 1 consists of a cylinder block (1) in which pistons (2) driven by oil hydraulics are arranged so as to be axially movable. Pressure oil (23) is fed into the inlet opening (24) and via a connecting channel (25) to a controller (22), ie via its peripheral channel (26), a connecting hole (27) to the pressure kidney (28) and from there to a control hole (29) and from there into the cylinder space between the right end of the piston (2) and the left end of the synchronizing rod (6).

As a result of this arrangement, when pressure oil is introduced, the piston (2) moves to the left, generates a pulling force on the rotating device (9-12) via the synchronizing rod (6), causing the swash ring (12) to rotate due to its one-sided inclined surface .

Perforated disc (9) is rotatably supported in the swash ring (12) by means of an inner bearing (11) which is held by circlips (16, 17). Swash ring (12), on the other hand, is rotatably held on the outside by means of an outer bearing (13) between the cylinder block (1) and cover (14), and on the inside by means of a locking ring (15). As soon as the synchronizing rod (9) is under tensile force, the swash ring (12) is set in rotary motion because of its inclined surface inclined to the left relative to the axis of rotation, which on the drive shaft (19) by means of bolts (20) and from there to the control (22) by means of bolts (21) is transmitted.

As soon as pressure oil (23) is fed into the inlet (24) and via the control (22) to the oil side of the piston (2), the piston (2) and the synchronizing rod (6) pull on the perforated disc (9), which causes it to wobble and thereby turn swash ring (12). Since this rotary movement is transmitted to the control (22) via the drive shaft (19), the pressure kidney (28) slides over the control bores (29) so that the cylinders are supplied with pressure oil in succession.

Since opposing control bores (29) connect opposing cylinders to the tank kidney (40), the oil is passed through the connecting bore (41), swash chamber (42) and connecting duct (43) to the outlet (44), from where it is used as tank oil (45) flows to the tank.

Because of the stroke of a plurality of pistons (2), suction water (30) is drawn into the left-hand cylinder chambers via suction check valves (32) as soon as the piston (2) moves to the right. From there, the water is displaced to the outlet (34) via pressure check valves (33) as soon as the piston (2) is pushed to the left in the direction of the pressure and suction valves (32, 33). Since the driving hydraulic oil (23) is continuously fed into the machine, its inner parts also move continuously, whereby the pressurized water is also continuously displaced, preferably preferably by a number of three pistons (2), to the outlet (34).

It is obvious that because of the wobbling of the perforated disc (9) during one revolution, the heads of the synchronizing rods (6) must have the shape of partial balls (8) which are held on the synchronizing rods (6) by locking rings (48). These partial balls (8) are in turn held in an articulated manner in spherical caps (7) which slide a little on the perforated disc (9) in order to compensate for a slight radial path due to the wobble angle of the perforated disc (9).

It is also evident that the end faces (46) of the synchronizing rods (6) must not touch the swash ring (12) at high speed in order to avoid braking. Therefore, according to the invention, a thrust washer (10) must be provided which e.g. is held by the locking ring (18) and tumbles together with the perforated disc (9).

In order to avoid mixing water and oil, a ventilation duct (5) can be provided which releases any leakage into the atmosphere. Of course, a pressure relief and / or unloader valve can be provided.

The pistons (2) and synchronizing rods (6) can also be connected by a radially and angularly movable joint in order to compensate for manufacturing tolerances and deformations.

If the synchronizing rods (6) are designed to absorb radial forces resulting from the inclined position of the perforated disc (9), the piston (2) can remain free of lateral forces, so that a "floating" piston arrangement is possible, i.e. the pistons are only guided in the seals (3, 4) and / or relatively narrow guides of the cylinder block (1) and / or guide rings located therein.

Of course, the controller (22) can be replaced by any other controller, e.g. described in: "2nd Fluid Power Symposium, January 1971, Paper E4, BHRA, Cranfield, Bedford, England."

Fig. 3 shows another embodiment of the invention, according to which the control (22) is replaced by a mushroom head (51), which is balanced by a compensating head (52) and sealed in perforated disc (9) by means of seals (53, 54) and is pressed onto its counter surface by compression spring (55).

The direct contact of end faces (46) of the synchronizing rods (6) with respect to the thrust washer (10) is replaced by flat partial balls (56) which distribute any pressure surges over the thrust washer (10). In this case, the piston (2) is stepped into an oil piston (57) and a water piston (58) in order to increase the water pressure compared to the oil pressure in accordance with the surface conditions. The pressure relief or unloader valve (38) is replaced by a pressure control valve (59).

Figure 3 further shows an oil unloader (61-64) controlled by the water pressure spool system (70-74).

When the pressure is released, the oil pressure from chamber (65) acts on a ball (62) which opens against the force of spring (71), the force being transmitted via the water piston (72) and oil piston (63), so that the oil flow is largely depressurized discharges into channel (67). When the water pressure increases, the resulting force of the water piston (72) is added to the spring force so that the ball (62) is pressed more firmly into its seat in the insert (61) until the ball closes completely at maximum pressure. When the pressurized water (75) is shut off (e.g. by releasing a spray gun), the pressure control valve (59) opens so that high pressure is maintained in the outlet (75) and chamber (76) while chamber 77 is depressurized. As a result, the water piston (72) remains in its left position against the force of the spring (71) and full oil relief occurs, since the ball (62) can move freely to the left.

It must be expressly stated that ball (62) can also be made to work in the opposite direction, i.e. by moving the ball seat to the other side of the ball. Of course, other directional control valves with piston tappets instead of balls can also be used.

4 finally shows a comparison of conventional machines with regard to size or construction volume and weight W2 compared to the device according to the invention.

It is obvious that conventional machines of known design cannot be used generally on the aforementioned vehicles, e.g. Forklifts, construction machinery, trucks, etc.

Furthermore, it is obvious that the piston axes of the machine according to the invention do not have to be parallel, but can also be arranged on a conical pitch circle (cone shell).

It goes without saying that the water-side piston part and the oil-side piston part can be completely separate, but can also be made of one piece and coated. The water-side piston part can be sealed by two soft seals, the space between which is connected to the suction side. This can also be done on the oil side.

Of course, all known hydraulic elements such as pressure limiting valves, flow regulators, oil unloaders, check valves, seals etc. can be used together with the high-pressure cleaner according to the invention or in this itself. The same applies to the water-side controls.

Claims (14)

1. Hydraulically driven high-pressure cleaner comprising at least three pistons (2) on one side being impinged with hydraulic oil and on their other side in continuous operation acting on a second liquid to be displaced, a synchronization rod (6) and a turning means (9 to 12) including a wobble ring (12), wherein the turning means (9 to 12) drives a control (22 or 51, resp.), characterized in that said turning means (9 to 12) comprises a perforated disc (9), that said synchronization rod (6) is arranged on each driving oil side and oppositely to the piston side facing the fluid to be displaced, of an hydraulically operated piston, wherein said synchronization rod (6) has positive fit and is movably connected to said perforated disc (9) rotatably supported in said wobble ring (12) and driving it such that the axial movement of said piston (2) is converted into a rotational movement of said wobble ring (12), wherein said control (22 or 51, resp.) directs the hydraulic oil to said piston (2) and again away from it such that the axial movement thereof is caused.
2. High-pressure cleaner as defined in claim 1, characterized in that a hinge is disposed between said piston (2) and its synchronization rod (6) such that a slight radial and angular movement becomes possible between said pistion (2) and said synchronization rod (6).
3. High-pressure cleaner as defined in one of claims 1 to 2, characterized in that said piston (2) has different diameters at the water-side end and the other oil-side end thereof.
4. High-pressure cleaner as defined in one of clams 1 to 3, characterized in that said piston (2) is guided by its seals (3, 4) and/or the support rings thereof.
5. High-pressure cleaner as defined in one of claims 1 to 3, characterized in that at least a first fluid-side of said piston (2) is sealed by at least two seals of which at least one clearing is connected to the low-pressure area of the first liquid.
6. High-pressure cleaner as defined in one of claims 1 to 5, characterized in that the central lines of said pistons (2) lie on a cone envelope.
7. High-pressure cleaner as defined in one of claims 3 to 6, characterized in that in the water-side valve block a water-controlled water control piston (72) is arranged such that it actuates an hydraulic Valve (61 to 64) disposed in said cylinder block (1).
8. High-pressure cleaner as defined in claim 7, characterized in that said hydraulic valve (61 to 64) at least to a high degree leaves the hydraulic oil without pressure as long as high water pressure only is present at the outlet (75).
9. High-pressure cleaner as defined in one of claims 3 to 8, characterized in that all hydraulic and/or all water-side valve elements are arranged within the housing of said high-pressure cleaner.
10. High-pressure cleaner as defined in one of claims 1 to 9, characterized in that the free ends of said synchronization rods (6) each comprise a partial ball (56).
11. High-pressure cleaner as defined in one of claims 1 to 10, characterized in that said wobble ring (12) includes an axis of rotation in parallel to the outside diameter and/or a axis of rotation inclined with respect thereto.
12. High-pressure cleaner as defined in one of claim 1 to 11, characterized in that said wobble ring (12) touches at least one outside bearing and at least one inside bearing.
13. High-pressure cleaner as defined in one of claims 1 to 12, characterized in that a stop disc (10) is arranged between the free end of said synchronization rods (6) and the inside bearing (11) of said wobble ring (12).
14. High-pressure cleaner as defined in one of claims 7 to 8, characterized in that said hydraulic valve (61 to 64) closes in case of high pressure acting only in the water outlet (75).

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