WO2013107519A1

WO2013107519A1 - Piston pump for a high-pressure cleaning device

Info

Publication number: WO2013107519A1
Application number: PCT/EP2012/050867
Authority: WO
Inventors: Robert Nathan
Original assignee: Alfred Kärcher Gmbh & Co. Kg
Priority date: 2012-01-20
Filing date: 2012-01-20
Publication date: 2013-07-25
Also published as: EP2805051A1; US20140328698A1; EP2805051B1; CN103998778B; CN103998778A; BR112014012998A2

Abstract

The invention relates to a piston pump (10) for a high-pressure cleaning device, having a plurality of pump chambers (22), into which in each case one piston (24) which can move to and fro dips and which are flow-connected in each case via an upstroke valve (26) to a suction inlet (14) and via a delivery valve (28) to a pressure outlet (16), wherein the pistons (24) are surrounded in each case by a seal ring (46) which is supported in the radial direction by a ring wall (50) and in the axial direction by a supporting ring (56). In order to develop the piston pump in such a way that it can be produced and assembled less expensively, it is proposed according to the invention that the piston pump (10) comprises a single-piece supporting plate (54) which forms the supporting rings (56) and surrounds the ring walls (50) in the circumferential direction.

Description

PISTON PUMP FOR A HIGH-PRESSURE CLEANING DEVICE

The invention relates to a piston pump for a high-pressure cleaning device, with a plurality of pump chambers, in each of which a reciprocable piston dips and which are in each case via a suction valve with a suction inlet and a pressure valve with a pressure outlet in flow communication, wherein the piston in each case by a sealing ring are surrounded, which is supported in the radial direction by an annular wall and in the axial direction of a support ring.

With the help of such piston pumps, a liquid, preferably water, can be pressurized and directed to an object to be cleaned or a surface to be cleaned. For this purpose, the pistons can be driven to a reciprocating motion, for example by means of a swash plate, so that the volumes of the pumping chambers change periodically and sucked liquid from the suction inlet via the suction valves in the pumping chambers, there pressurized and discharged through the pressure valves and the pressure outlet can be. At the pressure outlet, for example, a pressure hose can be connected, which carries at its free end a delivery member for the pressurized liquid, for example a spray nozzle or a spray lance.

The pump chambers are each sealed by means of a sealing ring which surrounds the piston immersed in the pump chamber in the circumferential direction. The sealing ring may for example form a sealing lip which is pressed under the pressure prevailing in the pump chamber pressure against the lateral surface of the piston. In the radial direction of the sealing ring is usually supported by an annular wall and for support in the axial direction is usually a support ring is used. Such piston pumps are known for example from DE 44 45 519 Cl. In many cases, the liquid in the pump chambers is pressurized to over 100 bar. The piston pump is therefore subject during its operation considerable mechanical loads and must have a high mechanical strength. Therefore, the piston pumps usually have a considerable material thickness. This is associated with not inconsiderable manufacturing costs. In addition, the relatively high material strength has the consequence that the housing of the piston pump, which is usually produced in a casting process, during manufacture undergoes a long cooling process, which limits the production rate of the housing. This also increases the manufacturing cost of the piston pump.

Object of the present invention is to develop a piston pump of the type mentioned in such a way that it can be produced more cheaply.

This object is achieved in a piston pump of the generic type according to the invention in that it comprises a one-piece support plate, which forms the support rings and surrounding the annular walls in the circumferential direction.

All support rings, which support the sealing rings each surrounding a piston in the circumferential direction in the axial direction, are integrated in the piston pump according to the invention in a one-piece support shield. This allows a simpler installation of the piston pump, since all support rings can be positioned in a single assembly step.

The present invention used for use one-piece support plate also has the function of the above-mentioned ring walls in

Surround circumferential direction and thus support the ring walls in the radial direction. This makes it possible to reduce the material used for the ring walls, because the concomitant reduction in the mechanical strength of the ring walls is compensated by the support plate surrounding all the ring walls in the circumferential direction. The one-piece support plate thus makes it possible to reduce the material used for the pump housing and to simplify the assembly of the piston pump.

In an advantageous embodiment, the support plate on a plurality of support sleeves, in each of which an annular wall is immersed. As already explained, the sealing of the pumping spaces by means of the sealing rings, which each surround a piston and in turn are surrounded by an annular wall and are supported on a support ring in the axial direction. The annular wall immersed in the advantageous embodiment of the invention in a support sleeve, which is defined by the one-piece support shield.

It can be provided, for example, that the piston pump according to the invention comprises three pistons, each immersed in a pump chamber, each pump chamber having an annular wall which supports a sealing ring in the radial direction and which dips into a support sleeve of the support plate. The annular wall may be formed particularly thin-walled in such a configuration and yet the liquid to be delivered can be placed in the pump chambers under a high pressure.

In a particularly preferred embodiment of the invention, the piston pump comprises a pump block, which has the pumping chambers and which is integrally connected to the support plate. This makes it possible to additionally reduce the manufacturing costs and also to simplify the assembly of the piston pump.

As an integral connection, for example, an adhesive bond can be used. An adhesive layer may be provided, for example, between the respective annular walls surrounding a respective sealing ring in the circumferential direction and the support plate surrounding the annular wall in the circumferential direction. This allows a mechanically strong connection between the pump block and the support plate. The adhesive layer can also serve as a sealing element for the liquid to be delivered. In addition, through the adhesive bond a uniform stress distribution and power transmission can be achieved. Voltage peaks, which can often occur with a screw connection, can be reduced.

In a particularly preferred embodiment of the invention, the pump block is welded to the support plate. This allows a particularly strong connection that can withstand very high pressures reliably.

It is advantageous if each of a sealing ring in the circumferential direction surrounding ring walls are each welded to a surrounding support sleeve.

Preferably, the pump block and the support plate are made of a plastic material. This makes it possible to connect the pump block with the support plate, for example by an ultrasonic welding. If the support plate comprises support sleeves, as has been explained above, the support sleeves can each be placed on an annular wall and welded thereto in a structurally simple manner. The welded joint allows a permanent fixation of the two parts to each other, so that they can then perform no relative movement more. As with the weld joint and an optimal seal can be achieved, additional seals between the two parts can be omitted.

It is advantageous if the support plate is seated on a guide plate having guide members for guiding the piston in the axial direction. By means of the guide members of the guide plate, the pistons can be guided in the axial direction. At the same time the guide plate has the function to support the support plate in the axial direction.

It can be provided, for example, that the support plate preferably has coaxial with the support sleeves aligned support collar which sit on the guide plate and each surrounding a piston in the circumferential direction. With the help of the support collar, the support shield can be designed in a constructive way. Support the way on the guide plate. In addition, the use of the support collar has the advantage that the mechanical strength of the support plate is increased, the material thickness of the support plate can be kept relatively low.

The support collars preferably each have a drainage opening, for example a drainage slot. Via the drainage opening, liquid which inadvertently emerges from the pump chambers via the sealing ring surrounding a respective piston can be released to the environment.

A particularly high mechanical strength with relatively low use of material is achieved in a particularly preferred embodiment of the invention in that the support plate is supported by a convex guide plate which forms a lid for a swash plate housing. In such an embodiment of the support plate in the axial direction supporting guide plate is convex. This gives him a particularly high mechanical strength and allows to reduce the material strength of the guide plate. In addition to its function of guiding the pistons in the axial direction and supporting the support plate in the axial direction, the guide plate in such an embodiment performs the function of a cover for the swash plate housing, in which a swash plate is arranged, with which the pistons to achieve a reciprocating Cooperation together. The swashplate can be rotated about the longitudinal axis of the piston pump, and the swirling motion of the swashplate allows the pistons to be driven to reciprocate, under the action of which the volumes of the pumping chambers are periodically changed.

The following description of a preferred embodiment of the invention serves in conjunction with the drawings for further explanation. Show it : Figure 1 is a schematic longitudinal sectional view of an advantageous embodiment of a piston pump according to the invention;

Figure 2 is a plan view of a welded to a support plate pump block of the piston pump of Figure 1;

Figure 3 is a sectional view of the welded to the support plate pump block along the line 3-3 in Figure 2 and

Figure 4: a sectional view of the pump block and the support plate in the manner of an exploded view.

In the drawing, an advantageous embodiment of a piston pump according to the invention is shown schematically, which is generally occupied by the reference numeral 10. The piston pump 10 comprises a pump head 12 with a suction inlet 14, via which the piston pump 10 can be supplied with a liquid to be pressurized, preferably water. For example, a supply line can be connected to the suction inlet 14. The pump head 12 also has a pressure outlet 16 through which the pressurized fluid can be dispensed. To the pressure outlet 16, for example, a pressure hose can be connected, which carries at its free end a delivery member for the pressurized liquid, for example a spray lance or a spray nozzle.

The pump head 12 is mounted in the axial direction with respect to a pump longitudinal axis 18 on a pump block 20 having a plurality of pump chambers 22, in each of which a piston 24 is immersed. The piston pump 10 shown in the drawing has a total of three pump chambers, wherein in the drawing only one pump chamber 22 can be seen. The pump chambers are arranged distributed uniformly around the pump longitudinal axis 18 and each have the same radial distance to the pump longitudinal axis 18. The pump chambers 22 are in each case via a suction valve 26 to the suction inlet 14 and via a pressure valve 28 with a central pressure chamber 30 in flow communication, which form the pump head 12 and the pump block 20 between them. The pressure chamber 30 is adjoined in the axial direction by a pressure line 32 which is aligned coaxially to the pump longitudinal axis 18 and via which the pressure chamber 30 is in flow communication with the pressure outlet 16.

In the pressure chamber 30, a central, rotationally symmetrical to the pump longitudinal axis 18 formed insert member 34 is held, which is formed in the manner of a piston and surrounded by two sealing rings which are disposed between the insert member 34 and the wall of the pressure chamber 30. The insert part 34 forms a holding element for closing springs 40 of the pressure valves 28. On its front side facing away from the closing springs 40, the insert part 34 has a recess 42 into which a closing body 44 of a central non-return valve dips, by means of which a central passage of the insert valve 34 can be closed.

The sealing of the pumping spaces 22 in the direction away from the pump head 12 takes place in each case with the aid of a sealing ring 46, which has a sealing lip 48 and surrounds a piston 24 in the circumferential direction. The sealing ring 46 is surrounded by a collar-like annular wall 50 of the pump block 20 in the circumferential direction. The annular wall 50 is cylindrical and aligned coaxially with a piston longitudinal axis 52. Relative to the piston longitudinal axis 52, the annular wall 50 supports the sealing ring 46 radially.

On the pump head 12 side facing away from the pump block 20 is followed by a one-piece support plate 54, the configuration of which results in particular from Figure 4. It has support rings 56 which each support a sealing ring 46 in the axial direction. Each support ring 56 is followed by a cylindrical support sleeve 58, which is aligned coaxially with a piston longitudinal axis 52 and surrounds an annular wall 50 in the circumferential direction. On the back of the support plates 54 facing away from the support plate 54 carries a plurality of cylindrical support collar 60, which is also coaxial with the piston longitudinal axes 52 are aligned and each having a drainage opening in the form of a drainage slot 62.

The support plate 54 is integrally formed and made of a plastic material. Also for the production of the pump head 12 and the pump block 20 is in each case a plastic material used. In the area of the annular walls 50 and the surrounding support sleeves 58 of the pump block 20 is welded to the support plate 54. Each annular wall 50 is thus integrally connected via a circumferential weld with a support sleeve 58 into which the annular wall 50 is immersed. This gives the ring walls 50 a high mechanical stability, without having to have a considerable material thickness.

With the support collar 60, the support plate 54 is supported in the axial direction on a guide plate 64 having a plurality of guide members in the form of coaxially aligned with the piston longitudinal axes 52 guide sleeves 66. At each guide sleeve 66 is a piston 24 slidably. By means of the guide sleeves 66 each surrounding return spring 68, the pistons are pressed against a swash plate 70 which is rotatably mounted about the pump axis 18 in a swash plate housing 72. The guide plate 54 forms a convexly outwardly curved cover for the swash plate housing 72, on which the guide plate 64 is supported in the axial direction.

The swash plate 70 can be rotated in the usual manner by a known per se and therefore not shown in the drawing drive motor, in particular an electric motor to the pump axis 18, wherein the rotational movement of the motor shaft via a schematically illustrated in Figure 1 gear 74 on the Swash plate 70 is transmitted.

By a respective annular wall 50 in the circumferential direction surrounding weld with a support sleeve 58, a high mechanical stability is achieved, the material used for both the pump block 20 and for the support plate 54 can be kept relatively low. After welding of the pump block 20 to the support plate 54, each of a piston 24 circumferentially surrounding sealing rings 46 are fixed reliably both in the axial direction and in the radial direction, so that by means of the sealing rings 46 a high tightness can be achieved even at high pressures. Nevertheless, liquid exiting from the pump chambers 22 can escape to the outside via the drainage slots 62.

To mount the piston pump 10, the guide plate 64 can be placed on the swash plate housing 72 after the swash plate 70 has been mounted, wherein previously the pistons 24 were inserted into the guide sleeves 66. Subsequently, the support plate 54 can be placed on the guide plate 64, after previously the suction valves 26 were mounted in the pump block 20 and the pump block 20 has been welded to the support plate 54. In this case, each of a sealing ring 46 surrounding annular walls 50 in the circumferential direction in the support sleeves 58 a. The ring walls 50 are each welded to a support sleeve 58. For this purpose, an ultrasonic welding can be used, since both the pump block 20 and the support plate 54 are made of a plastic material.

After inserting the pressure valves 28 and the central insert member 34 including the central closure member 44 in the pump block 20 can be placed in a subsequent assembly step, the pump head 12 in the axial direction of the pump block 20, wherein between the pump head 12 and the pump block 20, an elastically deformable sealing ring 76 is positioned. In a subsequent assembly step, the pump head 12 can then be clamped to the pump block 20. For this purpose, for example, a clamping element 77 can be used, which is shown only schematically in FIG. 1 and engages the end face 78 of the pump head 12 facing away from the pump block 20. The clamping element 77 can engage over the pump head 12, the pump block 20 and the support plate 54 and can be screwed with radially outwardly pointing screw receptacles of the guide plate 64. The manufacture and assembly of the piston pump 10 is thus very simple. The use of the one-piece support plate 54 with the support sleeves 60 surrounding a respective annular wall 20 and the support collar 60 aligned coaxially with the support sleeves 58 makes it possible to minimize the material usage of the support shield 54 and also the material usage of the pump block 20 in the area of the annular walls 50.

Claims

PATENT APPLICATIONS

1. Piston pump for a high-pressure cleaner, with a plurality of pump chambers (22), in each of which a reciprocating piston (24) is immersed and in each case via a suction valve (26) with a suction inlet (14) and via a pressure valve (28) a pressure outlet (16) are in fluid communication, wherein the pistons (24) are each surrounded by a sealing ring (46) which is supported in the radial direction by an annular wall (50) and in the axial direction by a support ring (56), characterized in that the piston pump (10) has a one-piece support plate which forms the support rings (56) and surrounds the annular walls (50) in the circumferential direction.

2. Piston pump according to claim 1, characterized in that the support plate (54) has a plurality of support sleeves (58), in each of which an annular wall (50) is immersed.

3. Piston pump according to claim 1 or 2, characterized in that the piston pump (10) comprises a pump block (20) having the pumping chambers (22) and which is integrally connected to the support plate (54).

4. Piston pump according to one of the preceding claims, characterized

characterized in that the pump block (20) with the support plate (54) is welded.

5. Piston pump according to claim 2, characterized in that the annular walls (50) are each welded to a surrounding support sleeve (58).

6. Piston pump according to one of the preceding claims, characterized in that the pump block (20) and the support plate (54) are made of a plastic material.

7. Piston pump according to one of the preceding claims, characterized

characterized in that the support plate (54) on a guide plate (64) is seated, the guide members for guiding the piston (24) in the axial direction.

8. Piston pump according to claim 7, characterized in that the support plate (54) supporting collar (60) which rest on the guide plate (64) and each surround a piston (24) in the circumferential direction.

9. Piston pump according to claim 8, characterized in that the support collar (60) each have a drainage opening (62).