Sealing system

Abstract

The invention proceeds from a sealing system for separating two pressure zones, comprising a seal arranged between a shaft and a structural component. According to the invention, the seal is axially movably arranged in a groove, wherein: the seal has sealing surfaces and the groove has groove-sealing surfaces; according to the pressure conditions in the pressure zones the seal can be moved into a first functional position or a second functional position.

Description

[0001] Sealing system

[0002] The invention relates to a sealing system for separating two pressure areas with two functional positions and the use of such a sealing system in a hydrodynamic retarder.

[0003] Advances in technology require sealing systems to be adapted to meet these increased requirements. A particular requirement for a sealing system is that it must have different properties, especially sealing properties, for different operating conditions.

[0004] One application for a sealing system with different functional positions is in a hydrodynamic retarder. It is generally known that retarders have a working chamber that can be filled with a working fluid to hydrodynamically transfer torque from a driven rotor to a stator.

[0005] The retarder's working chamber is connected to a retarder working medium circuit in which the working medium, e.g. oil or cooling water from the vehicle's cooling circuit can circulate. Radial shaft seals and a rectangular ring are used to seal the retarder circuit from the rotor shaft. The rectangular ring is a separating element which is positioned between the working chamber and the shaft seals. The rectangular ring is used as a relief element for the radial shaft seals so that no excessive pressure from the working chamber can act on the radial shaft seals, although a certain degree of leakage is desired depending on the pressure conditions. The sealing effect of the rectangular ring therefore depends on the applied pressure in braking or non-braking operation. Since the rotor shaft rotates in both operating states, it is necessary for the sealing points to be lubricated and cooled by an oil flow in both operating states.DE 10 2020 107 729 A1 discloses a retarder with a cooled sealing system. The sealing system comprises a rectangular ring arranged between the working chamber and the radial shaft seal. This ring is designed to allow a leakage flow that changes direction depending on the operating condition. However, due to the design, the leakage flow can only be influenced to a limited extent and depends primarily on manufacturing tolerances.

[0006] From EP 2 666 980 A1 a sealing system is known which can be moved in two functional positions.

[0007] Another sealing system is known from DE 1 162 464 B and DE 6 929 111 U.

[0008] DE 10 242 735 A1 discloses a retarder with a sealing system.

[0009] The object of the invention is to propose a sealing system with improved properties.

[0010] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims.

[0011] The starting point is a sealing system for separating two pressure areas comprising a seal that is arranged between a shaft and a component.

[0012] According to the invention, the seal is arranged so as to be axially displaceable in a groove, the seal having sealing surfaces and the groove having groove sealing surfaces, the seal being movable into a first functional position or a second functional position depending on the pressure conditions in the pressure regions. According to the invention, the seal is arranged so as to be axially movable in the groove. Different sealing properties can be implemented in the functional positions. In a preferred embodiment, it can be provided that in the first functional position a separation of the pressure regions is achieved and in the second functional position a pressure equalization between the pressure regions is made possible by at least one of the sealing surfaces and / or one of the groove sealing surfaces having recesses, so that in the second functional position a channel remains between the pressure regions.

[0013] Preferably, the channel is formed by providing recesses, designed as a pocket area in the sealing surface of the seal and a recess next to the groove. The recess can, for example, be designed circumferentially on the shaft, and the at least one pocket area in the sealing surface can be formed by a partial area, so that, viewed circumferentially, only a relatively small channel area is created when the sealing surface of the seal is moved against the groove sealing surface into the second functional position.

[0014] In a preferred design, the sealing surfaces of the seal are symmetrical, and the channel size can be defined by the design and dimensioning of the recess. This eliminates the need to pay attention to the seal's alignment when installing the seal.

[0015] Furthermore, the seal can be provided with a radial sealing surface whose diameter D can be elastically adjusted by means of a sliding area. The sliding area can also be designed such that the inner diameter can be enlarged to such an extent that the seal can be mounted over the shaft.

[0016] Also proposed is a retarder comprising a described sealing system, wherein the first pressure zone comprises a working chamber of the retarder, and wherein the seal is movable into a first or a second functional position depending on the pressure ratio between the pressure zones. In the event of an overpressure in the first pressure zone, the seal is moved into the first functional position, in which the pressure zones are sealed from one another.

[0017] Furthermore, the sealing system in the retarder can be designed such that in the event of an overpressure in the second pressure range, the seal is moved into the second functional position, so that pressure equalization between the pressure ranges is made possible by at least one of the sealing surfaces and / or one of the groove sealing surfaces having recesses, so that in the second functional position a channel remains between the pressure ranges, which allows pressure equalization.

[0018] In retarder mode, there are two main operating states: braking and non-braking. It is advantageous if a sealing system seals the circuit from the outside during braking and allows air or oil to flow into the circuit from the outside during non-braking. The invention enables the circuit to be sealed from the outside during braking and allows oil or air to enter the circuit during idling.

[0019] The invention is explained below with reference to the figures. The figures show in detail:

[0020] Fig.1 Sealing system in the first functional position

[0021] Fig.2 Sealing system in the second functional position

[0022] Fig.3 View of seal

[0023] Figure 1 shows the sealing system 1 in its first functional position. The sealing ring 4 is arranged in the groove 11 of the shaft 3. Depending on the pressure conditions in the pressure zones 5.1 and 5.2, the seal 4 has been moved axially so that the first sealing surface 7.1 of the seal 4 is pressed against the groove sealing surface 12.1. In the sealing plane 6, complete sealing is achieved with respect to the second pressure zone 5.2. The seal 4 is designed as a sealing ring or a rectangular ring. The end faces of the seal 4, i.e. the first sealing surface 7.1 and the second sealing surface 7.2, form continuous surfaces, with the surfaces having recesses 13.1 and 13.2, as also shown in Figure 3, which reduce the sealing surfaces 7.1 and 7.2 in the radial direction. The effective diameter of the seal is thus changed by the recesses 13.1 and 13.2.In the first functional position, it is nevertheless ensured that a full-surface contact is created between the first sealing surface 7.1 and the groove sealing surface 12.1 in the sealing plane 6. This allows the seal 4 to be designed symmetrically.

[0024] Next to the groove 11, another recess is provided, here designed as a recess 14. The combination of the pocket area 13.2 and the recess 14 forms a channel 10 between the shaft 3 and the seal 4.

[0025] Figure 2 shows the second functional position; in this functional position, pressure equalization between pressure zones 5.1 and 5.2 can occur via channel 10. In a retarder, the position shown corresponds to the seal 4, the position in non-braking operation, in which an air and / or oil volume flow or leakage flow can reach the components behind it through channel 10.

[0026] Recesses within the meaning of the invention can also be formed by bores or openings. The use of elastic elements is also conceivable. The desired air and / or oil flow rate can be adjusted by changing the size of the recess 13.2 and / or the recess 14.

[0027] To simplify the installation of the seal 4, the seal 4 has a sliding area 16 by means of which the diameter D1 of the seal can be changed, so that easy installation over the shaft is possible.

[0028] For better understanding, Figure 3 shows the seal 4 in a perspective view. This view shows the sliding area 16, which allows the inner diameter D1 of the seal 4 to be varied. This allows the seal to be slid over the shaft 3 up to the groove by expanding it. Also clearly visible are one of the recesses 13.2 and the sealing surfaces 7.2, which form a continuous surface that is not significantly interrupted by the design of the sliding area 16.

[0029] List of reference symbols

[0030] 1 sealing system

[0031] 2 housings

[0032] 3 Wave

[0033] 4 Seal

[0034] 5.1 first pressure area

[0035] 5.2 second pressure area

[0036] 6 Density level

[0037] 7.1 first sealing surface

[0038] 7.2 second sealing surface

[0039] 8.1 Working medium

[0040] 9 Auxiliary volume flow

[0041] 10 channel

[0042] 11 grooves

[0043] 12.1. 12.2 Groove sealing surface

[0044] 13.1..1 13.2 Recess

[0045] 14 puncture

[0046] 15 Radial sealing surface

[0047] 16 Sliding area

[0048] D1 inner diameter

Claims

Patent claims 1. Sealing system (1) for separating two pressure zones (5.1, 5.2) comprising a seal (4) arranged between a shaft (3) and a component (2), wherein the seal (4) is axially displaceable in a groove (11), wherein the seal (4) has sealing surfaces (7.1, 7.2) and the groove (11) has groove sealing surfaces (12.1, 12.2), wherein, according to the pressure conditions in the pressure zones (5.1, 5.2), the seal (4) is movable into a first functional position or a second functional position, characterized in that the seal (4) has a radial sealing surface (15) whose diameter D is elastically adaptable by a sliding area (16).

2. Sealing system (1) according to claim 1 characterized in that in the first functional position a separation of the pressure areas (5.1 , 5,2) is achieved and in the second functional position a pressure equalization between the pressure areas (5.1 , 5.2) is enabled by the fact that at least one of the sealing surfaces (7.1 , 7.2) and / or one of the groove sealing surfaces (12a, b) has recesses (13.1 , 13.2 , 14) so ​​that in the second functional position a channel (10) remains between the pressure areas.

3. Sealing system (1 ) according to claim 2 characterized in that the channel (10) is formed by providing recesses (13.1 , 13.2 , 14), designed as pocket area (13.1 , 13.2) in the sealing surface (7.1 ) of the seal (4) and indentation (14) next to the groove (11 ).

4. Sealing system (1 ) according to claim 1 characterized in that the sealing surfaces (7.1 , 7.2) of the seal (4) are symmetrical. Retarder comprising a sealing system (1) according to one of claims 1 to 4 characterized in that the first pressure area (5.1 ) comprises a working chamber of the retarder, wherein, according to the pressure ratio between the pressure areas (5.1 , 5.2) the seal (4) is movable into a first or a second functional position, wherein, in the event of overpressure in the first pressure area (5.1 ), the seal (4) is moved into the first functional position, in which the pressure areas are sealed to each other. Retarder according to claim 5, characterized in that in the event of overpressure in the second pressure area the seal (4) is moved into the second functional position, so that pressure equalization between the pressure areas (5.1 , 5,2) is made possible by the fact that at least one of the sealing surfaces (7.1 , 7.2) and / or one of the groove sealing surfaces (12a, b) has recesses (13.1 , 13.2 , 14) so ​​that in the second functional position a channel (10) is formed between the pressure areas (5.1 , 5,2) remains, which allows for pressure equalization.

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