SEALING BUSHING AND HIGH-PRESSURE CLEANING DEVICE

Description

[0001] The present invention relates to a high-pressure cleaning device according to the preamble of claim 1.

[0002] High-pressure cleaning devices of this type with sealing bushings are known, for example, from the subsequently published DE 10 2019 134 040 A1.

[0003] The sealing bushing serves to seal a hollow shaft rotating relative to the sealing bushing by forming a gap seal between an inner surface of the sealing bushing and the outer surface of the hollow shaft. US Patent 3,874,637 A discloses a sealing bushing that has a cylindrical base body with several window openings arranged side by side in the base body perpendicular to an axis of rotation, and circumferential sealing ring grooves molded at intervals on both sides of the window openings in an outer surface of the base body, extending in the direction of the axis of rotation. The spacing of the spaced-out sealing ring grooves in a first surface region of the base body is greater than the spacing of the spaced-out sealing ring grooves in a second surface region of the base body opposite the first surface region.

[0004] Further sealing bushings are known from EP 0 154 308 A2, EP 0 885 643 B1 and US 4 854 545 A. The high-pressure cleaning device in which such sealing bushings are used typically consists of an input hollow shaft and several output hollow shafts fluidically connected to the input hollow shaft. An output hollow shaft housing that accommodates the output hollow shafts rotates with the input hollow shaft, which is housed in an input hollow shaft housing.

[0005] The high-pressure cleaning device described in the aforementioned publication has proven its worth.

[0006] A problem has been found to arise in that the rotation of the output hollow shaft housing causes centrifugal forces to act on the sealing bushings that seal the output hollow shafts against the output hollow shaft housing. These forces cause the sealing bushing, which is usually floating in the hollow shaft housing, to be pressed into an eccentric position rather than centrally in its designated receptacle. This leads to increased leakage due to the resulting eccentric gap and potentially to premature wear of the sealing bushings due to friction against the hollow shaft housing.

[0007] The object of the present invention is to further develop a high-pressure cleaning device in such a way that the sealing bushing remains as centrally located as possible in the receptacle in the hollow shaft housing even when subjected to centrifugal forces.

[0008] This problem is solved by a high-pressure cleaning device having the features of claim 1.

[0009] The high-pressure cleaning device according to the invention has an input hollow shaft housing, an input hollow shaft which is mounted in the input hollow shaft housing so as to be rotatable about an axis of rotation relative to it, and which can be connected to a hydraulic pressure source.

[0010] The high-pressure cleaning device also has an output hollow shaft housing which is mounted to rotate around the axis of rotation relative to the input hollow shaft housing together with the input hollow shaft.

[0011] The output hollow shaft housing contains at least one output hollow shaft that is mounted to rotate about an axis of rotation.

[0012] A fluid channel of the input hollow shaft is fluidically coupled to a fluid channel of the output hollow shaft via a connecting channel.

[0013] In the output hollow shaft housing, a section of the output hollow shaft is enclosed by a sealing bushing, which is arranged in a positionally and rotationally fixed manner to the output hollow shaft housing and forms a gap seal with the output hollow shaft.

[0014] The sealing bushing has a cylindrical base body with several window openings arranged side by side in the base body perpendicular to an axis of rotation, and circumferential sealing ring grooves formed on both sides of the window openings on an outer surface of the sealing bushing in the direction of the axis of rotation, in which sealing rings are received to form static seals to the output hollow shaft housing.

[0015] The sealing ring grooves are aligned at an angle to a plane of rotation of the output hollow shaft housing.

[0016] The distance between the spaced sealing ring grooves is greater in a cylindrical area of ​​the base body of the sealing bushing that is radially away from the axis of rotation of the output hollow shaft housing than the distance between the spaced sealing ring grooves in a cylindrical area of ​​the base body of the sealing bushings that is radially close to the axis of rotation of the output hollow shaft housing.

[0017] The varying distance between the sealing ring grooves across the outer surface of the sealing bushing results in differently sized contact areas in the region between the sealing ring grooves, which, with a corresponding installation position of the sealing bushing and pressure being applied, results in a force that counteracts the centrifugal force when the sealing bushing is rotated around an axis of rotation located outside the sealing bushing.

[0018] This results in the sealing bushing remaining centered or nearly centered in the recess provided for it in the hollow shaft housing.

[0019] Advantageous embodiments of the invention are the subject of the dependent claims.

[0020] In an advantageous embodiment of the high-pressure cleaning device, the inner diameter of the sealing bushings in the area of ​​the gap seal is the same or almost the same on both sides of the window openings.

[0021] In another preferred embodiment, the input hollow shaft is coupled to the output hollow shafts via a mechanical transmission.

[0022] According to a further advantageous embodiment of the high-pressure cleaning device according to the invention, the sealing ring grooves are aligned obliquely to a plane perpendicular to the axis of rotation of the base body.

[0023] The inclined orientation of the sealing ring grooves across the outer surface of the sealing bushing creates an area between the sealing ring grooves that, when developed, corresponds to two trapezoids with their bases abutting each other. To achieve the desired effect (compensating for centrifugal force), the longer bases of the trapezoids are positioned radially outwards to the axis of rotation outside the sealing bushing, while the shorter bases of the trapezoids are positioned radially inwards to the axis of rotation outside the sealing bushing.

[0024] According to an advantageous embodiment of the high-pressure cleaning device according to the invention, the sealing ring grooves are aligned such that the larger distance between the spaced-apart sealing ring grooves decreases continuously towards the smaller distance.

[0025] In an advantageous further development, the outer surface of the base body is formed as a pocket-like first depression in an area surrounding the window openings in a ring shape.

[0026] In another embodiment, an inner surface of the base body is formed as a pocket-like second depression in an area surrounding the window openings in a ring shape.

[0027] According to a further advantageous embodiment, the base body of the sealing bushing is made of a bearing metal, preferably bronze.

[0028] Preferred embodiments are explained in more detail below with reference to the accompanying drawings. They show: Figure 1 shows a schematic sectional view through an embodiment of a sealing bushing according to the invention; Figures 2a, b, c show different schematic views of the Figure 1Figure 3 shows a schematic isometric representation of an embodiment of a high-pressure cleaning device according to the invention, and Figure 4 shows a cross-sectional view of a partial area of ​​the sealing bushing shown in Figure 3. Figure 3 The high-pressure cleaning device shown and Figure 5 a close-up of an area of ​​the high-pressure cleaning device showing the arrangement of one of the sealing bushings.

[0029] In the following figure descriptions, terms such as top, bottom, left, right, front, back, etc., refer exclusively to the exemplary representation and position of the sealing bushing, base body, sealing ring grooves, high-pressure cleaning device, input hollow shaft, output hollow shaft, and the like as chosen in the respective figures. These terms are not to be understood as restrictive; that is, these references may change due to different working positions, mirror-symmetrical design, or similar factors.

[0030] In the Figure 1 and 2a to 2c is an embodiment of a sealing bushing according to the invention, designated by reference numeral 5. The sealing bushing 5 is particularly suitable for installation in a high-pressure cleaning device, such as those described in the Figures 3-5 is shown.

[0031] The sealing bushing 5 has a cylindrical base body 51. Several window openings 52 are provided approximately centrally in the direction of an axis of rotation R of the base body 51. These openings are used in the high-pressure cleaning device 1 according to... Figures 3 to 5 They serve to facilitate the flow of a liquid under high pressure, for example water.

[0032] High pressure here refers to pressures from 100 bar up to about 4000 bar, particularly preferably from 150 bar up to 2000 bar, which are used in such high-pressure cleaning devices 1.

[0033] In the direction of the axis of rotation R, on both sides of the window openings 52, as shown in the Figure 1 , 2a, 2b and 2c As shown, circumferential sealing ring grooves 55 are formed at intervals between each other in an outer surface 53 of the base body 51.

[0034] The sealing ring grooves 55 are located in the Figure 1 The cross-section shown is preferably rectangular in shape and serves to accommodate a sealing ring 9, as for example in the Figures 4 and 5 This can be seen. Depending on the cross-section of the sealing ring 9 to be used, other cross-sectional designs for the sealing ring grooves 55 are also conceivable.

[0035] As in the Figure 1 , 2a, 2b and 2c As shown, the sealing ring grooves 55 are oriented obliquely to an imaginary plane, the surface normal of which is formed by the axis of rotation R of the base body 51.

[0036] As in the Figure 1 and 2bas shown, wherein a distance d 1 of the spaced-apart sealing ring grooves 55 in a first shell area of ​​the base body 51 is greater than a distance d 2 of the spaced-apart sealing ring grooves 55 in a second shell area of ​​the base body 51 opposite the first shell area, i.e. offset by 180° in the direction of rotation of the sealing ring grooves 55.

[0037] In the version shown here, the Figure 2b The maximum distance d 1 on the left side of the lateral surface decreases continuously from the minimum distance d 2 visible on the right side of the lateral surface, which has the advantage that a conventional sealing ring 9 can be inserted into the sealing ring grooves 55.

[0038] In principle, a stepped design of the circumferential sealing ring grooves 55 would also be conceivable.

[0039] The installation direction of the sealing bushing 5 in the high-pressure cleaning device is important for its intended use and will be explained in more detail below.

[0040] How the Figure 1 and 2a to 2c As can be further seen, the outer surface 53 of the base body 51 is formed as a pocket-like first circumferential depression 56 in an area surrounding the window openings 52 in a ring-like manner.

[0041] In the state installed in the high-pressure cleaning device 1, this first recess 56 serves to form a fluid chamber, from which the high-pressure fluid travels along the outer shell 53 of the base body 51 of the sealing bushing 5 to the area of ​​the sealing rings 9 inserted into the sealing ring grooves 55.

[0042] Furthermore, an inner surface 54 of the base body 51 is formed as a pocket-like circumferential second recess 57 in an area surrounding the window openings 52 in a ring-like manner.

[0043] The second recess 57 also serves, in the state installed in the high-pressure cleaning device, to form a further fluid chamber, from which the high-pressure fluid forms a gap seal 7 along the inner surface 54 of the base body 51 of the sealing bushing 5 with an outer surface of an output hollow shaft 6 received by the sealing bushing 5, as shown in Figure 4 and Figure 5 is shown.

[0044] A bearing metal, preferably bronze, is particularly suitable as a material for manufacturing the sealing bushing 5. Manufacturing the sealing bushing 5 from another bearing material is also conceivable.

[0045] As mentioned above, the sealing bushing 5 is particularly suitable for use in a high-pressure cleaning device 1, as shown below. Figures 3 to 5 will be explained in more detail.

[0046] The high-pressure cleaning device 1 has an input hollow shaft housing 2 and an input hollow shaft 3 which is rotatably mounted in the input hollow shaft housing 2 relative to it about a rotational axis R 3, 4 and which can be connected to a hydraulic pressure source.

[0047] A [unclear] is used to connect the hydraulic pressure source. Figure 3 Pressure port 25 shown.

[0048] The input hollow shaft housing 2 can be fixed in place on a bracket (not shown here) via a mounting flange 21 molded onto it.

[0049] What's next in Figure 3As can be seen, the high-pressure cleaning device 1 also has an output hollow shaft housing 4 which is rotatable relative to the input hollow shaft housing 2 together with the input hollow shaft 3 about the axis of rotation R 3, 4.

[0050] The output hollow shaft housing 4 is shaped here such that two output hollow shafts 6 can be mounted in it. It is also conceivable to design an output hollow shaft housing 4 in which only one or more than two, for example three or four output hollow shafts 6, can be mounted. In the latter case, the output hollow shaft housing 4 is preferably star-shaped in plan view instead of beam-shaped as in the [reference to be added]. Figure 3 The design variant shown is shaped as shown.

[0051] The output hollow shafts 6 are arranged apart from each other in the output hollow shaft housing 4 and are mounted to rotate about axes of rotation R 6 in the output hollow shaft housing 4.

[0052] The axes of rotation R 6 are arranged parallel and offset from the axis of rotation R 3, 4 of the input hollow shaft 3. It is also conceivable to arrange the axis(s) of rotation R 6 at an angle, preferably at an acute angle, to the axis of rotation R 3, 4 of the input hollow shaft 3.

[0053] As in Figure 4 As shown, a fluid channel 31 of the input hollow shaft 3 is fluidically coupled to respective fluid channels 61 of the output hollow shafts 6 via connecting channels 42. For this purpose, the input hollow shaft 3 projects into a through-bore provided for this purpose in the output hollow shaft housing 4.

[0054] In the area of ​​a lower end of the fluid channel 31, it splits into two outlets 33, which open into the two connecting channels 42 for conveying the high-pressure fluid into the fluid channels 61 of the output hollow shafts 6.

[0055] Static seals 34, for example in the form of sealing rings, are placed around the connection points of the output hollow shaft housing 4 to the outputs 33 of the input hollow shaft 3, as shown in Figure 4 is shown.

[0056] What next in the Figures 4 and 5 As shown, the sealing bushings 5 ​​are arranged in a position- and rotationally fixed manner relative to the output hollow shaft housing 4.

[0057] Each of the sealing bushings 5 ​​encompasses a section of the respective output hollow shaft 6, forming a gap seal 10. As explained above, spaced-apart circumferential sealing ring grooves 55 are formed on the outer shell surfaces 53 of each of the sealing bushings 5, in which sealing rings 9 are received to form static seals to the output hollow shaft housing 4.

[0058] The sealing ring grooves 55 are aligned obliquely to a plane of rotation of the output hollow shaft housing 4 with reference to the components of the high-pressure cleaning device 1.

[0059] The sealing bushings 5 ​​are installed in an orientation such that the distance d 1 of the spaced-apart sealing ring grooves 55 in a cylindrical area of ​​the base body 51 of the sealing bushings 5 ​​located radially away from the axis of rotation R 3, 4 of the output hollow shaft housing 4 is greater than the distance d 2 of the spaced-apart sealing ring grooves 55 in a cylindrical area of ​​the base body 51 of the sealing bushings 5 ​​located radially away from the axis of rotation R 3, 4 of the output hollow shaft housing 4.

[0060] As explained at the beginning, this prevents the sealing bushings 5 ​​from being pressed towards the output hollow shaft 6 by centrifugal force when the output hollow shaft housing 4 rotates with the input hollow shaft 3.

[0061] This is achieved by the fact that the high-pressure fluid in the gap between the outer shell 53 of the sealing bushing 5 and the inside of the recesses in the output hollow shaft housing 4 rests on a larger area of ​​the sealing bushing 5 than on the side of the outer shell 53 of the sealing bushing 5 that is radially closer to the axis of rotation R 3, 4 of the output hollow shaft housing 4.

[0062] The propagation of the high-pressure fluid in a direction axial to the axis of rotation R 3, 4 of the output hollow shaft housing 4 is more narrowly limited by the sealing rings 9 being closer together than on the opposite side of the outer shell 53 of the sealing bushings 5, where the sealing rings 9 are further apart.

[0063] The inner diameter of the sealing bushings 5 ​​is preferably the same or almost the same in the area of ​​the gap seal 12 on both sides of the window openings 52.

[0064] What's next in Figure 4As shown, the input hollow shaft 3 is coupled to the output hollow shaft 6 via a mechanical transmission 8.

[0065] The mechanical transmission 8 has a first gear wheel 81 which is mounted on the output hollow shaft 6 in a rotationally fixed manner, and a second gear wheel 82 which meshes with the first gear wheel 81 and further meshes with a gear wheel 24 which is fixed in place on the input hollow shaft housing 2.

[0066] In order to drain leakage fluid from the gap seals 10, as in the Figures 4 and 5 As shown, a leakage channel 44 is provided in an area above and below the sealing bushing 5 in the output hollow shaft housing 4.

[0067] The gear wheels 81, 82 are preferably covered by a cover 45 of the output hollow shaft housing 4.

[0068] Nozzles 64 are also arranged at the outlets 63 of the output hollow shafts 6, protruding from a further cover 46 of the output hollow shaft housing 4. Reference symbol list

[0069] 1 High-pressure cleaning device 2Input hollow shaft housing 21Mounting flange 22First housing 23Second housing 24Gear wheel 25Pressure connection 3 Input hollow shaft 31 Fluid channel 32 Hollow shaft body 33 Output 34 Seal 4 Output hollow shaft housing 41 Base body 42 Connection channel 43 Recess 44 Leakage channel 45 Cover 46 Cover 5 Sealing bushing 51 Base body 52 Window opening 53 Outer shell surface 54 Inner shell surface 55 Sealing ring groove 56 Recess 57 Recess 6 Output hollow shaft 61 Channel 62 Input channel 63 Output 64 Nozzle 65 Recess 7-gap seal 8 Gearbox 81 First gear wheel 82 Second gear wheel 9 sealing ring d1 distance d2 distance ti depth ta depth R 3, 4 axis of rotation R 6 axis of rotation R axis of rotation

Claims

1. A high-pressure cleaning device (1) comprising - an input hollow shaft housing (2), - an input hollow shaft (3) mounted in the input hollow shaft housing (2) so as to be rotatable relative thereto about an axis of rotation (R3, 4), which can be connected to a hydraulic pressure source, - an output hollow shaft housing (4) mounted so as to be rotatable relative to the input hollow shaft housing (2) together with the input hollow shaft (3) about the axis of rotation (R3, 4), - at least one output hollow shaft (6) arranged in the output hollow shaft housing (4) and mounted so as to be rotatable about an axis of rotation (R6), - wherein a fluid channel (31) of the input hollow shaft (3) is fluidically coupled via a connecting channel (42) to a fluid channel (61) of the output hollow shaft (6), - wherein a sealing bushing (5) that surrounds a section of the output hollow shaft (6) to form a gap seal (10) is arranged in the output hollow shaft housing (4) such that it is fixed in position and rotationally locked to the output hollow shaft housing (4), - wherein the sealing bushing (5) comprises a cylindrical-shell-shaped base body (51) with a plurality of window openings (52) formed in the base body (51) adjacent to one another perpendicular to an axis of rotation (S), as well as - circumferential sealing ring grooves (55) spaced apart from one another are formed on an outer surface (53) of the sealing bushing (5) on both sides of the window openings (52) in the direction of the axis of rotation (S), in which sealing rings (9) are received to form static seals with respect to the output hollow shaft housing (4), characterized in that - a distance (d1) between the spaced-apart sealing ring grooves (55) in a shell region of the base body (51) of the sealing bushing (5) that is radially distant from the axis of rotation of the output hollow shaft housing (4) is greater than a distance (d2) between the spaced-apart sealing ring grooves (55) in a circumferential region of the base body (51) of the sealing bushing (5) that is radially close to the axis of rotation (R4) of the output hollow shaft housing (4).

2. High-pressure cleaning device (1) according to claim 1, characterized in that an inner diameter of the sealing bushing (5) in the region of the gap seal (12) is equal or nearly equal on both sides of the window openings (52).

3. High-pressure cleaning device (1) according to claim 1 or 2, characterized in that the input hollow shaft (3) is coupled to the output hollow shaft (6) via a mechanical gearbox (8).

4. High-pressure cleaning device (1) according to one of the preceding claims, characterized in that the sealing ring grooves (55) of the sealing bushing (5) are oriented obliquely to a plane perpendicular to the axis of rotation (S) of the base body (51).

5. High-pressure cleaning device (1) according to one of the preceding claims, characterized in that the sealing ring grooves (55) of the sealing bushing (5) are oriented such that the greater distance (d1) between the spaced-apart sealing ring grooves (55) continuously decreases toward the smaller distance (d2).

6. High-pressure cleaning device (1) according to any of the preceding claims, characterized in that the outer surface (53) of the base body (51) of the sealing bushing (5) is formed as a pocket-like first recess (56) in a region annularly surrounding the window openings (52).

7. High-pressure cleaning device (1) according to one of the preceding claims, characterized in that an inner surface (54) of the base body (51) of the sealing bushing (5) is formed as a pocket-like second recess (57) in a region annularly surrounding the window openings (52).

8. High-pressure cleaning device (1) according to one of the preceding claims, characterized in that the base body (51) of the sealing bushing (5) is made of a bearing metal, preferably bronze.