Rotatingly Driven Filter Element with Contactless Seal

Abstract

A rotatingly driven filter element for filtering incoming air is to be arranged in a machine part upstream of an intake chamber of a cooling system or of a combustion air distribution device of an internal combustion engine of a self-propelled working machine. The filter element has a rim area with a circumferentially extending section provided with air guiding elements oriented toward and projecting into the intake chamber. The rim area, when the filter element is arranged in the machine part, is positioned at a minimal spacing relative to the machine part and an air gap is formed between the rim area and the machine part. The air guiding elements guide purified inflow air out of the intake chamber into a region of the air gap to effect a sealing action of the air gap.

Claims

1. A rotatingly driven filter element configured to be arranged in a machine part upstream of an intake chamber of a cooling system or of a combustion air distribution device of an internal combustion engine of a self-propelled working machine and configured to filter incoming air, the filter element comprising: a rim area comprising a circumferentially extending section comprising air guiding elements oriented toward and projecting into the intake chamber, wherein the rim area, when the filter element is arranged in the machine part, is positioned at a minimal spacing relative to the machine part and an air gap is formed between the rim area and the machine part; wherein the air guiding elements are configured to guide purified inflow air out of the intake chamber into a region of the air gap to effect a sealing action of the air gap.

2. The filter element according to claim 1, wherein the air guiding elements comprise outer edges that are oriented so as to be leading in a rotational direction of the filter element.

3. The filter element according to claim 1, wherein the air guiding elements are formed as one piece together with the circumferentially extending section of the filter element.

4. The filter element according to claim 1, wherein the air guiding elements each comprise a base region comprising an outflow opening, wherein the air guiding elements are configured to guide the purified inflow air through the outflow opening into the region of the air gap.

5. The filter element according to claim 1, wherein the machine part comprises a stationary sheet metal cover arranged at the rim area and comprising a surface matched to an outer contour of the circumferentially extending section, wherein the circumferentially extending section is externally surrounded contactless at a minimal spacing by the sheet metal cover, wherein, between the outer contour of the circumferentially extending section and the surface of the sheet metal cover facing the circumferentially extending section, the air gap is formed as an annular space.

6. The filter element according to claim 5, wherein the annular space comprises a course comprising a directional deflection, wherein the directional deflection is formed by a shape of the outer contour of the circumferentially extending section and by a shape of the sheet metal cover.

7. The filter element according to claim 5, wherein the circumferentially extending section comprises a region comprising outflow openings of the air guiding elements, wherein the sheet metal cover covers at least the region comprising the outflow openings of the air guiding elements.

8. The filter element according to claim 5, wherein the air gap comprises a first air gap section and a second air gap section, wherein a gap width of the second air gap section is smaller than a gap width of the first air gap section.

9. The filter element according to claim 5, wherein the air gap comprises a first air gap section and a second air gap section, wherein the first air gap section (S1) is open toward the environment and the second air gap section (S2) is open toward the interior, wherein the air guiding elements generate in the first air gap section (S1) relative to the environment a static air pressure p.sub.S1Ap.sub.U and inside the first air gap section (S1) a static air pressure p.sub.S1>p.sub.S1A, wherein the air guiding elements generate in the second air gap section (S2) relative to the intake chamber a static air pressure p.sub.S2Ap.sub.I and inside the second air gap section (S2) a static air pressure p.sub.S2>p.sub.S2A, and wherein a pressure difference ratio Q.sub.p=(p.sub.S1Ap.sub.U)/(p.sub.S2Ap.sub.I) is defined.

10. The filter element according to claim 1, wherein the air guiding elements each delimit an inflow opening which is not located in a rotation-symmetrical surface of the circumferentially extending section, wherein the inflow opening is facing in a rotational direction of the air guiding elements.

11. A self-propelled working machine comprising a rotatingly driven filter element for filtering incoming inflow air, the filter element arranged in a machine part of the self-propelled working machine upstream of an intake chamber of a cooling system of the self-propelled working machine or of a combustion air distribution device of an internal combustion engine of the self-propelled working machine, the filter element comprising: a rim area comprising a circumferentially extending section comprising air guiding elements oriented toward and projecting into the intake chamber, wherein the rim area is positioned at a minimal spacing relative to the machine part and an air gap is formed between the rim area and the machine part; wherein the air guiding elements are configured to guide purified inflow air out of the intake chamber into a region of the air gap to effect a sealing action of the air gap.

12. The self-propelled working machine according to claim 11, wherein the air guiding elements comprise outer edges that are oriented so as to be leading in a rotational direction of the filter element.

13. The self-propelled working machine according to claim 11, wherein the air guiding elements are formed as one piece together with the circumferentially extending section of the filter element.

14. The self-propelled working machine according to claim 11, wherein the air guiding elements each comprise a base region comprising an outflow opening, wherein the air guiding elements are configured to guide the purified inflow air through the outflow opening into the region of the air gap.

15. The self-propelled working machine according to claim 11, wherein the machine part comprises a stationary sheet metal cover arranged at the rim area and comprising a surface matched to an outer contour of the circumferentially extending section, wherein the circumferentially extending section is externally surrounded contactless at a minimal spacing by the sheet metal cover, wherein, between the outer contour of the circumferentially extending section and the surface of the sheet metal cover facing the circumferentially extending section, the air gap is formed as an annular space.

16. The self-propelled working machine according to claim 15, wherein the annular space comprises a course comprising a directional deflection, wherein the directional deflection is formed by a shape of the outer contour of the circumferentially extending section and by a shape of the sheet metal cover.

17. The self-propelled working machine according to claim 15, wherein the circumferentially extending section comprises a region comprising outflow openings of the air guiding elements, wherein the sheet metal cover covers at least the region comprising the outflow openings of the air guiding elements.

18. The self-propelled working machine according to claim 15, wherein the air gap comprises a first air gap section and a second air gap section, wherein a gap width of the second air gap section is smaller than a gap width of the first air gap section.

19. The self-propelled working machine according to claim 15, wherein the air gap comprises a first air gap section and a second air gap section, wherein the first air gap section (S1) is open toward the environment and the second air gap section (S2) is open toward the interior, wherein the air guiding elements generate in the first air gap section (S1) relative to the environment a static air pressure p.sub.S1Ap.sub.U and inside the first air gap section (S1) a static air pressure p.sub.S1>p.sub.S1A, wherein the air guiding elements generate in the second air gap section (S2) relative to the intake chamber a static air pressure p.sub.S2Ap.sub.I and inside the second air gap section (S2) a static air pressure p.sub.S2>p.sub.S2A, and wherein a pressure difference ratio Q.sub.p=(p.sub.S1Ap.sub.U)/(p.sub.S2Ap.sub.I) is defined.

20. The self-propelled working machine according to claim 11, wherein the air guiding elements each delimit an inflow opening which is not located in a rotation-symmetrical surface of the circumferentially extending section, wherein the inflow opening is facing in a rotational direction of the air guiding elements.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0034] FIG. 1 is a perspective top view of a cooling system.

[0035] FIG. 2 is a detail view of the abutting region of the filter element relative to the rigid machine part as shown in FIG. 1.

[0036] FIG. 3 is a detail view of the detail III shown in FIG. 2.

[0037] FIG. 4 is a detail view of the detail IV shown in FIG. 3

[0038] FIG. 5 is a modified simplified embodiment.

[0039] FIG. 6 shows schematically the filter element arranged on a self-propelled working machine.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0040] The rotating filter element 1 of a cooling system 20 which is illustrated in FIG. 1 is a basket formed of perforated sheet metal in the embodiment and is comprised of a rotation-symmetrical at least approximately cylindrical sheet metal wall 2 and a flat cover disk 3 as an outer closure of the sheet metal wall 2. The sheet metal wall 2 and/or the flat cover disk 3 are perforated for performing the function of air cleaning. As the sucked-in ambient air is flowing through the screen apertures in the perforated sheet metal into the intake chamber 22 of the cooling system 20, the dirt particles that are greater than the aperture width of the screen apertures in the perforated sheet metal are retained at the exterior surface of the sheet metal wall 2 and of the cover disk 3.

[0041] The sheet metal wall 2 comprises in the vicinity of the neighboring rigid machine part 7 a non-perforated circumferentially extending section 4. The non-perforated circumferentially extending section 4 and thus the sheet metal wall 2 end at the side which is facing the machine part 7 with a shape-stabilizing crimp 5; however, the section 4 can also be embodied as a simple edge. This circumferentially extending section 4 comprises inwardly oriented air guiding elements 6 which are arranged at the circumference of the circumferentially extending section 4 in a uniformly repeating sequence.

[0042] The cooling system 20 is comprised in the embodiment substantially of the filter element 1, the intake chamber 22, the heat exchanger 24, and the suction fan 26 which together form a circumferentially approximately closed flow channel for the cooling air that is passing through as inflow air.

[0043] In the exemplary embodiment, the air guiding elements 6 are formed directly in the cylindrical sheet metal wall 2 and are thus connected non-separably with the cylindrical sheet metal wall 2. In the embodiment, the inflow opening 30 of the air guiding elements 6 is oriented approximately radially relative to the sheet metal wall 2; the sheet metal structure of the air guiding elements 6 passes from this inflow opening 30 continuously into the sheet metal wall 2. The inflow opening 30 is oriented with an outer edge leading in rotational direction R of the filter element 1 so that, when the filter element 1 is rotating, inflow air which is located in the intake chamber 22 can flow easily into the inflow opening 30. Forming of such an air guiding element 6 from the cylindrical sheet metal wall 2 as one piece (monolithic) with the sheet metal wall 2 can be realized by stamping or laser machining with subsequent bending or deep drawing to form an inwardly oriented, monolithic sheet metal tab or sheet metal lens or sheet metal nose.

[0044] The circumferentially extending section 4 comprises in the region of the air guiding elements 6 outlet openings 32 through which the inflow air can exit at the side of the circumferentially extending section 4 facing away from the intake chamber 22. Outlet openings 32 are illustrated in FIGS. 3 to 5.

[0045] The filter element 1 is rotatably supported on a shaft 10. The filter element 1 can be driven from the exterior or by a motor which is connected to the shaft 10. It is however also possible to drive the filter element 1 by fan wheels in the intake flow which are in driving connection with the shaft 10.

[0046] Correspondingly and coaxially relative to the circumferentially extending section 4 of the rotating filter element 1 that is provided with the air guiding elements 6, a rotation-symmetrical, approximately cylinder-shaped sheet metal cover 8 is fixedly correlated with the machine part 7; the sheet metal cover 8 is at least partially visible in FIGS. 2 to 4. The sheet metal cover 8, which can be seen particularly well in FIGS. 3 and 4, comprises at the side which is facing the machine part 7 a radially inwardly oriented crimp 9. The sheet metal cover 8 extends axially at least approximately across the entire axial length of the circumferentially extending section 4 at the rotation-symmetrical sheet metal wall 2. In regard to its geometric shape and correspondingly in regard to its function, the sheet metal cover 8 with its crimp 9 can also be integrated completely into the machine part 7 and, for example, can be embodied as an injection molded part with integrated bearing for the rotating filter element 1. The inner diameter of the rotation-symmetrical sheet metal cover 8 is slightly greater than the outer diameter of the circumferentially extending section 4 at the rotation-symmetrical sheet metal wall 2 so that an air gap section S1 with a gap width W1 is formed. The air gap section S1 forms about the circumferentially extending section 4 an annular space which is delimited outwardly by the sheet metal cover 8.

[0047] The rotating filter element 1 is correlated axially in such a way relative to the machine part 7 and thus relative to the rotation-symmetrical sheet metal cover 8 that between the crimp 5 facing the machine part or a simple edge of the circumferentially extending section 4 an air gap section S2 with a gap width W2 is formed at the rotation-symmetrical sheet metal wall 2 and the radial crimp 9 at the sheet metal cover 8. The air gap section S2 is a continuation of the annular space of the air gap which is formed in the region of the air gap section S1. The gap width W2 in the embodiment is adjusted to be smaller than the existing gap width W1 so that the air resistance at the air gap section S2 is greater than at the air gap section S1. When the filter element 1 is standing still and the suction blower 26 is switched on, the adjusted gap widths W1 and W2 provide no barrier for small dirt particles which can reach the interior of the machine as a result of the vacuum p.sub.I existing in the interior of the filter element 1 relative to the ambient pressure p.sub.U (p.sub.I<p.sub.U).

[0048] The air-sealing action of the device is effective only upon rotating operation of the filter element 1.

[0049] Between the air gap section S1 and the air gap section S2, the annular space experiences a directional deflection in the region of the crimp along its course, in particular by 90.

[0050] The circumferential velocity of the air guiding elements 6 must exhibit a minimum value which depends on the realizable gap widths W1 and W2. By a correspondingly high circumferential velocity of the air guiding elements 6 in predetermined direction, the inwardly projecting air guiding elements 6 will catch a portion of the air which is located in the interior of the filter element 1 and force it outwardly in the direction of the cylinder-shaped sheet metal cover 8, wherein at the exit S1A of the air gap section S1 relative to the environment partially a static air pressure p.sub.S1Ap.sub.U is adjusted and in the air gap section S1 generally a static air pressure p.sub.S1>p.sub.S1A is adjusted in order to prevent inflow of air from the environment. At the same time, in this way at the exit S2A of the air gap section S2 relative to the interior (p.sub.I) of the filter element a static air pressure p.sub.S2Ap.sub.I is generated and in the air gap section S2 generally a static air pressure p.sub.S2>p.sub.S2A is generated. Therefore, a ratio Q.sub.p of the pressure differences results:

Q.sub.p=(p.sub.S1Ap.sub.U)/(p.sub.S2Ap.sub.I).

[0051] The ratio Q.sub.p of the pressure differences is affected by the gap width W1>W2 and the circumferential velocity of the air guiding elements 6 but is adjustable only with difficulty due to technically caused manufacturing tolerances. Due to the described air pressure conditions in the air gap sections S1 and S2 of the air gap, the air flow which is generated by the rotating air guiding elements 6 is divided into two partial air flows, wherein the air flow rate oriented through the air gap section S1 in outward direction into the environment, depending on the ratio Q.sub.p of the pressure differences, is greater or smaller than the air flow rate returning through the narrower air gap section S2 of the air gap.

[0052] In the theoretical optimal state p.sub.S1A=p.sub.U, no air loss to the exterior will occur and no dirt particles will reach the machine interior of the cooling system. Due to fluctuations of the vacuum p.sub.I<p.sub.U which is existing in the machine interior of the cooling system, in practical operation at the exit S1A of the air gap section S1 relative to the environment partially an air pressure p.sub.S1A>p.sub.U must be adjusted so that a minimal portion of the inflow air having passed through the filter element will return again through the air gap section S1 into the environment and will not be available for cooling.

[0053] In FIG. 5, a modified embodiment is illustrated in which the air guiding elements 6 are of a simpler configuration. Also, a crimp is not provided at the circumferentially extending section 4.

[0054] With this device, with simply producible technical means and minimal manufacturing tolerances, a contactless air sealing action at rotating filter elements can be generated that prevents dirt particles reliably from entering the machine interior of the cooling system without using wear-prone brush or rubber seals, wherein the risk of injury relative to the prior art is excluded.

[0055] FIG. 6 shows schematically an example of a self-propelled working machine M provided with the filter element 1 of the invention in connection with a cooling system CS or an internal combustion engine CE.

[0056] The afore described embodiments serve only for explaining the invention. The invention is not limited to the embodiment. A person of skill in the art will have no difficulty to modify the embodiment in a suitable way in order to adapt the embodiment to a concrete application situation.

[0057] The specification incorporates by reference the entire disclosure of German priority document 10 2017 109 104.1 having a filing date of Apr. 27, 2017.

[0058] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.