Retarder with optimized air outlet

Abstract

Retarder with an air outlet system (1) through which exhaust air from an oil tank can be directed into the environment, wherein an exhaust air duct (2) is integrated in a retarder housing (10) which comprises an inlet opening (8) and an outlet opening (9), wherein the air outlet system (1) is arranged between outlet opening (9) and the environment, that the air outlet system (1) comprises a separator element (4) which has two subsections, an outer section (5) which extends outside and an inner section (6) which extends inside the exhaust air duct (2) characterized in that the separator element (4) is a wire mesh which has different mesh densities in the outer section (5) and in the inner section (6).

Description

The invention relates to a retarder with an optimized air outlet for introducing compressed air into the environment according to the preamble of the independent claim. Hydrodynamic retarders are used, for example, as wear-free brakes in motor vehicle drive trains to slow down the motor vehicle, especially a truck, bus or rail vehicle, by transmitting torque via a hydrodynamic circuit. The retarder comprises a toroidal working chamber formed by a rotor and a stator, which is connected via a channel system to a working fluid circuit with a working fluid tank. The working chamber is vented via a profiled venting system, through which air can be released via a connection between the working chamber and the environment. When the retarder is switched to braking mode, the air present in the working chamber during non-braking operation is discharged into the environment via the profiled venting system. An oil separator and a valve are provided to prevent working fluid, particularly oil, from escaping into the environment. Furthermore, a tank venting system is provided, through which air can be released via a connection between the working fluid tank and the environment. The air that is pumped into the working fluid tank to engage the retarder's braking operation is released back into the environment via this tank venting system when the retarder is switched back to non-braking operation. To prevent working fluid, particularly oil, from escaping into the environment with the air during the venting of the working fluid tank, an oil separator system and a valve are provided. Both venting systems are known, for example, from DE 10 2013 207 004 A1. Special requirements are placed on the tank venting system, as the working fluid must be forced from the working fluid tank into the working chamber using compressed air to switch the retarder into braking mode. The fill level of the working chamber, and thus the braking performance of the retarder, depends on the air pressure, which regulates the fill level. This means that compressed air must be released when switching to non-braking mode or when reducing the retarder braking torque. Oil foam is produced, particularly when the retarder shuts down, and the oil component of this foam must not escape into the environment. To prevent this, various channel configurations between the working fluid tank and the environment are known. For example, CN 1 05 697 602 A discloses a channel configuration with several separator chambers that have different structures. Furthermore, DE 10 2019 108 154 A1 discloses a device for closing the vent channel of a retarder, which connects the working chamber between the rotor and stator to the environment. A check valve with a float closes the channel when working fluid or working fluid foam is conveyed into the float chamber. In the flow direction between the working chamber and the sealing plane, means are provided to change the density of the foam, preferably a wire mesh that disrupts or alters the foam structure and thus ensures the buoyancy of the float. Patent CN 2 05 401 531 U proposes an oil-gas separation device for a hydraulic retarder that prevents oil from escaping into the environment via the exhaust air from the oil reservoir. The device comprises a first separation unit with a cylindrical oil-gas separating element made of a fiberglass layer, covered on both sides with nonwoven fabric, through which the compressed air flows radially. A second separation unit, in the form of a cylindrical housing, encloses the first unit and utilizes a spiral flow along the inner wall of the housing for further oil separation. An annular disk with a small through-hole, located within the second housing, extends the flow path. The separated oil is returned to the working chamber of the retarder via a return channel. The permissible oil discharge from modern retarders has been reduced to such an extent that the known precautions for reducing oil discharge when venting the working fluid tank are no longer sufficient. Also known is the use of porous sintered discs positioned at the outlet of the retarder's exhaust duct. These prevent coarse dirt from entering the retarder, ensure that the shutdown noise, as the air flows out of the retarder, does not exceed a certain noise level, and prevent any impairment of the retarder's shutdown times. The object of the invention is to provide a solution for improved treatment of the exhaust air at the outlet of the retarder exhaust air duct. The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims. A retarder with an air outlet system is proposed, through which exhaust air from an oil tank can be directed into the environment, wherein an exhaust air duct is integrated in a retarder housing, comprising an inlet opening and an outlet opening, with the air outlet system being arranged between the outlet opening and the environment. According to the invention, it is proposed that the air outlet system comprises a separator element having two sections: an outer section extending outside and an inner section extending inside the exhaust duct. The separator element is a wire mesh with different mesh densities in the outer and inner sections. In particular, the mesh density can be adapted to the expected residual oil quantity in the exhaust air stream. This design of the separator element significantly reduces the proportion of oil particles that enter the environment with the exhaust air, particularly because oil deposited on the separator element collects on the inner section and can drip back into the exhaust duct. In another embodiment, the air outlet system can include a guide device that provides an impact surface downstream of the separator element in the direction of exhaust air discharge and allows the exhaust air direction to be changed. The guide device can be a baffle plate against which the exhaust air impacts and is deflected. This prevents any residual oil particles from escaping uncontrollably into the environment. Residual oil collects on the baffle plate and can be directed away from there. This prevents the uncontrolled deposition of an oil film on adjacent components. Furthermore, the separating element can be made of a porous material. In a preferred embodiment, the inner section can be arranged in the exhaust air duct in such a way that the exhaust air entering the exhaust air duct through the inlet opening hits the inner section essentially transversely to the exhaust air outlet direction. Furthermore, an oil reservoir and / or an oil drain channel may be installed in the exhaust duct. To reduce the size of the individual separator elements, it may be necessary to provide at least three separator elements. The invention is explained below with reference to the figures. The figures show, in detail: Fig. 1: Sketch of an air outlet system; Fig. 2: Exhaust duct with three air outlet systems Fig. 1 shows a sketch of an air outlet system 1 for a retarder. The air outlet system 1 is shown, which consists of a separator element 4 and a guide device 7. Instead of the sintered discs behind the outlet opening 9 known from the prior art, the separator element 4 is designed here as a wire mesh, which can be shaped as shown. This wire mesh forms an insert that is inserted or installed into the retarder housing from the outside, so that an inner section 6 of the separator element 4 projects into the exhaust air duct 2. Oil particles in the exhaust air are trapped in the woven mesh structure and collect there. During the period between braking operations, i.e., when no airflow is introduced from a mechatronic retarder control unit (MRCU) 3 into the exhaust duct 2 via the inlet opening 8, oil accumulations on the surface of the wire mesh can drip back into the exhaust duct 2. This oil can be collected, for example, in a reservoir and / or discharged via an oil drain channel 11. The outer section 5 of the separator element 4 is located behind the outlet opening 9. After exiting the outer section 5, the air impacts the guide device 7, a sheet metal part designed as an air guide hood that redirects the compressed air. Any residual oil that escapes is thus collected and diverted in a controlled manner, ensuring that adjacent components remain as free as possible from oil mist. Fig. 2 shows the exhaust duct 2 with three air outlet systems 1. The inner sections 6 of the separator elements 4, which project into the exhaust duct 2, are arranged such that when the retarder is switched to non-braking mode, the air or compressed air from the tank flows laterally towards the inner sections 6 of the separator elements 4 via the retarder control unit 3, thereby clearing them. The number of filter elements, the length of the inner sections 6, and the position and size of the reservoir can vary. Reference symbol list 1 Air outlet system 2 Exhaust duct 3 Retarder control unit 4 Separator element 5 Outer section 6 Inner section 7 Guide device 8 Inlet opening 9 Outlet opening 10 Retarder housing 11 Oil drain channel

Claims

Retarder with an air outlet system (1) through which exhaust air from an oil tank can be directed into the environment, wherein an exhaust air duct (2) is integrated in a retarder housing (10) which comprises an inlet opening (8) and an outlet opening (9), wherein the air outlet system (1) is arranged between outlet opening (9) and the environment, that the air outlet system (1) comprises a separator element (4) which has two subsections, an outer section (5) which extends outside and an inner section (6) which extends inside the exhaust air duct (2), characterized in that the separator element (4) is a wire mesh which has different mesh densities in the outer section (5) and in the inner section (6). Retarder according to claim 1, characterized in that the air outlet system (1) comprises a guide device (7) which provides an impact surface in the direction of exhaust air discharge and by which the direction of exhaust air discharge can be changed. Retarder according to claim 1 or 2, characterized in that the inner section (6) is arranged in the exhaust air duct (2) such that the exhaust air entering the exhaust air duct (2) through the inlet opening (8) hits the inner section (6) substantially transversely to the exhaust air outlet direction. Retarder according to claim 2 according to one of the preceding claims, characterized in that an oil reservoir is arranged in the exhaust air duct (2). Retarder according to claim 2 according to one of the preceding claims, characterized in that an oil drain channel is arranged in the exhaust air duct (2). Retarder according to claim 1 according to one of the preceding claims, characterized in that the air outlet system (1) comprises at least three separator elements (4).

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