Retarder for high-temperature applications

Abstract

A braking system with a hydrodynamic retarder is proposed, coupled to the drive shaft of a system via a drive mechanism. The retarder comprises at least one rotor and one stator, both fixed to rotation on a shaft and arranged in a common housing, forming a torus-shaped working chamber, the shaft being driveable via a drive mechanism. According to the invention, it is proposed that the retarder comprises two sealing systems for separating two pressure areas, wherein a first shaft section of the shaft is arranged in the first pressure area and a second shaft section is arranged in the second pressure area, and a middle shaft section located between the shaft sections is not assigned to either of the pressure areas.

Description

[0001] The invention relates to a retarder for high-temperature applications according to the preamble of claim 1.

[0002] As known from DE 10 2020 125 509 B3, braking systems with hydrodynamic retarders are used in motor vehicles. The retarder comprises at least one rotor and one stator arranged on a shaft, which are arranged in a common housing and together form a toroidal working chamber. This chamber can be filled with a working medium from a working medium circuit via a working medium inlet for braking operation of the retarder and emptied back into the working medium circuit via a working medium outlet for non-braking operation of the retarder.

[0003] A retarder is also suitable for other applications, such as generating process heat in stationary or mobile systems. This utilizes a rotary motion that must be slowed down (braking energy) to convert it into waste heat.

[0004] Retarders can use different working fluids. During braking, the working fluid is heated by the shear forces between the stator and rotor. The braking energy must be dissipated in the form of heat energy. The ability to dissipate heat energy from the working fluid limits the retarder's braking performance to a certain extent.

[0005] The temperature range in which elastomer seals or mechanical seals and / or stationary elastomer seals can be operated is limited, particularly because the aging of the oil and the aging of the sealing elements entail the risk of premature failure.

[0006] From DE 10 2022 112 905 B3, for example, a sealing system is known with a seal that can be moved into two functional positions and in which the diameter of the radial sealing surface can be elastically adjusted.

[0007] From DE 10 2020 017 729 B3 a braking system is known that comprises a sealing system in which two pressure areas are separated from each other.

[0008] Regarding the environment, it is particularly important that no oil or working fluid leaks from the retarder and enters the environment.

[0009] The object of the invention is to propose a braking system with a hydrodynamic retarder that is still operationally safe even at higher operating temperatures of the working medium in the working chamber.

[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] A braking system with a hydrodynamic retarder is proposed, which is coupled to the system's drive axle via a high-gear drive. The retarder comprises at least one rotor and a stator mounted on a shaft in a rotationally fixed manner. These rotors are arranged in a common housing and together form a toroidal working chamber. The shaft can be driven via a high-gear drive.

[0012] The system can be any drivetrain, such as the drivetrain of a wind turbine or a vehicle. In a wind turbine, the retarder is directly coupled to the rotor axis of the wind turbine, allowing the wind energy to be continuously converted into thermal energy via the retarder. Alternatively, the wind energy could also be converted into electrical energy via a generator or into thermal energy via the retarder.

[0013] According to the invention, it is proposed that the retarder comprises two sealing systems for separating two pressure areas, wherein a first shaft section of the shaft is arranged in the first pressure area and a second shaft section is arranged in the second pressure area and a middle shaft section present between the shaft sections is not assigned to any of the pressure areas.

[0014] The two sealing zones allow for functional separation between the zones, allowing the working fluid, in particular, to be designed for higher operating temperatures. Higher operating temperatures have the advantage that the converted heat can also be used to operate processes requiring higher temperatures (process heat). Furthermore, the heat storage capacity is also better or greater at higher temperatures.

[0015] The shaft is preferably supported in the region of the first shaft section, with the support comprising bearings arranged in a high-drive housing. The high-drive and the support can be connected to a separate lubrication system, through which they are supplied with oil, with the first pressure area being sealed from the surrounding area.

[0016] Preferably, the retarder housing may be a common housing formed by a rotor housing and a stator housing, which forms the second pressure region, wherein the second pressure region is sealed from the ambient area by means of gap seals.

[0017] Furthermore, the working chamber of the retarder can be connected to a working medium circuit via a supply channel and an outlet channel so that it can be filled and emptied, wherein the working medium is a high-temperature working medium.

[0018] Preferably, the working medium is a high-temperature oil, a molten mineral salt or ionic liquid, or a metal with a low melting temperature. The working medium circuit comprises a heater or is heatable to bring the working medium back to operating temperature after cooling, in particular to liquefy it.

[0019] In a preferred embodiment, the surrounding area is an area formed by an intermediate housing, wherein the two pressure areas are aligned with each other via the intermediate housing. According to the invention, the housings—i.e., the booster housing, intermediate housing, and retarder housing—are coupled to each other, enabling a floating bearing in the booster housing, and the shaft with the rotor is arranged contactlessly and rotatably in the retarder housing.

[0020] Furthermore, the surrounding area is designed in such a way that it is suitable for collecting working medium, wherein means, in particular a pump, are provided to convey the working medium back into the working medium circuit.

[0021] In a preferred embodiment, the stator can be clamped between the rotor housing and the stator housing, wherein a remaining clamping channel is connected to the surrounding area or the clamping channel is permanently closed to the surrounding area.

[0022] The invention is explained below with reference to the figures. The figures show in detail: Fig. 1 System section of a braking system with the retarder Fig. 2 a, b Examples of leakage drainage on clamp ducts

[0023] Fig. 1 shows a system section of a braking system with a retarder 1 according to the invention. The essential structure of the retarder 1 is characterized in that there are two pressure areas 15a and 15b and a shaft 12 which projects into both pressure areas 15a, b.

[0024] This design allows the retarder to operate with a working fluid that tolerates high temperatures. High-temperature working fluids such as high-temperature oils, molten mineral salts, other salts (ionic liquids), or metals with a low melting point can be used here. To enable the use of these working fluids, a heater can be provided. This heater heats the relevant components or the areas surrounding the working fluid after the working fluid has cooled down, reheating them to such an extent that the working fluid liquefies. Such working fluids must not enter the oil circuit, for example, for storage.

[0025] For braking operation of the retarder 1, the working fluid is fed from a working fluid circuit (not shown) into the working chamber 13 via the supply channel 23, which is then pumped back from the retarder into the working fluid circuit via the outlet channel 24. (general StdT)

[0026] The shaft 11 is supported by bearings 18 located in the drive housing 22. The drive 17 comprises a drive gear 14, which is fixedly mounted on the shaft 1 and is driven by another drive gear.

[0027] The booster 17 and the bearings 18 are connected to a separate lubrication system (not shown), which supplies them with oil for lubrication and cooling. The first pressure area 15a is sealed from the surrounding area 19 outside the booster housing 22. The seal 26, e.g., a shaft seal, forms the first sealing system and is designed such that no oil can escape from the first pressure area 15a during operation. The shaft 11 is cantilevered via the bearings 18 in the area of ​​the first shaft section 16a, the first shaft end.

[0028] The second shaft section 16b, the second shaft end, with the rotor (11) mounted thereon for rotation, extends into the second pressure region 15b, which is formed or enclosed by the rotor housing 2 and the stator housing 3. A sealing system 20, 21 is provided to seal the shaft passage, which is adapted to the conditions of retarder operation, particularly high temperatures. The central shaft section 16c located between the shaft sections 16a, 16b is not assigned to any of the pressure regions 15a, b and extends through the surrounding region 19.

[0029] The second sealing system consists of a labyrinth seal 20 and a centrifugal disc 20, i.e., a non-contact sealing system in which leakage is unavoidable. The shaft passage is therefore only "sealed" in a leak-prone manner, and the remaining leakage must be captured, collected, and fed back to the retarder at a suitable location and at a suitable time.

[0030] The surrounding area 19 is formed by an intermediate housing 25, wherein both pressure areas 15a, b, or their housings 2, 3, and 22, are aligned with each other via the intermediate housing 25. The intermediate housing 25 forms an area in which the working medium can be collected, wherein means, in particular a pump, are provided to pump the working medium back into the working medium circuit.

[0031] In Fig. Figures 2a and b show examples of leakage drainage at clamping channels. In the context of the invention, leakage channels are gaps that form at the contact point between two components of the retarder, e.g., rotor housing 2 and stator housing 3.

[0032] Without a sealing element between two metal parts, it is very difficult to achieve a tight seal at the joint between two metal components that are clamped together by means of a screw connection.

[0033] To achieve a tight seal, the housing parts can be Fig. 2a. The welds are deliberately kept thin and unstable, so that the operating forces are (almost) exclusively or essentially transmitted by the mechanical structure, screws, fits, etc., and only to a lesser extent by the welds, so that the expected distortion of the weld seam can only cause minor forces compared to the structural operating forces.

[0034] In Fig. 2a, the stator is clamped between the housing parts, and the clamping channel 6 opens into a collecting chamber 9, and any leakage is discharged via the discharge channel 8. The discharge channel 8 can end in the intermediate housing 25 or be connected to it.

[0035] The second sealing system therefore does not include any seals that are elastomer seals at the points around which the working fluid flows List of reference symbols 1 retarder 2 rotor housings 3 Stator housing 4 Stator 5 fasteners 6 clamping channel 7 grooves 8 drainage channel 9 Assembly room 10 channel 11 Rotor 12 Wave 13 Workspace 14 High drive wheel 15a, b pressure ranges 16a, b, c wave sections 17 High shoot 18 camps 19 Surrounding area 20 Labyrinth seal 21 centrifugal disc 22 High-speed housing 23 Feed channel 24 Exit channel 25 intermediate housings 26 Seal

Claims

[1] Braking system with hydrodynamic retarder (1) which is coupled to the drive axle of a system via a high drive (17), comprising at least one rotor (11) arranged on a shaft (12) in a rotationally fixed manner and a stator (4), which are arranged in a common housing (2, 3) and together form a toroidal working space (13), wherein the shaft (12) can be driven via a high drive (17), characterized by in that the retarder comprises two sealing systems (20, 21, 26) for separating two pressure regions (15a, 15b), wherein a first shaft section (16a) of the shaft (12) is arranged in the first pressure region (15a) and a second shaft section (16b) is arranged in the second pressure region (15b), and a middle shaft section (16c) is present between the shaft sections (16a, 16b) and runs through an intermediate housing (25), wherein the intermediate housing (25) encloses a surrounding region (19) which is not assigned to any of the pressure regions (15a, b). [2] Braking system according to claim 1 characterized by that the bearing of the shaft (12) is arranged in the region of the first shaft section (16a), wherein the bearing comprises bearings (18) which are arranged in a high-drive housing (22). [3] Braking system according to claim 2 characterized by that the high drive (17) and the bearing are connected to a separate lubrication system via which they are supplied with oil, wherein the first pressure area is sealed from an ambient area (19). [4] Braking system according to claim 1 characterized by that the common housing, formed by a rotor housing (2) and a stator housing (3), forms the second pressure region (15b), wherein the second pressure region (15b) is sealed from the surrounding region (19) via gap seals (10, 20, 21). [5] Braking system according to claim 1 characterized bythat the working chamber (13) of the retarder (1) is connected to a working medium circuit via a supply channel (23) and an outlet channel (24) and can be filled and emptied via this, wherein the working medium is a high-temperature working medium. [6] Braking system according to claim 5 characterized by that the working medium is a high-temperature oil, a molten mineral salt or ionic liquid or a metal with a low melting temperature. [7] Braking system according to claim 5 characterized by that the working medium circuit includes a heater or is heatable. [8] Braking system according to claim 3 or 4 characterized by that the high drive housing (22) and the rotor housing (2) are aligned with each other via the intermediate housing (25). [9] Braking system according to claim 5 characterized bythat the surrounding area (19) is suitable for collecting working medium, wherein means, in particular a pump, are provided for conveying the working medium back into the working medium circuit. [10] Braking system according to claim 4 characterized by that the stator (4) is clamped between the rotor housing (2) and the stator housing (3), wherein a remaining clamping channel (6) is connected to the surrounding area (19) or the clamping channel (6) is permanently closed off from the surrounding area.

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