Hydrodynamic retarder with air outlet device

Abstract

A hydrodynamic retarder is proposed comprising a working medium tank, composed of a tank housing part and a tank lid, a pressure regulating valve for optionally connecting a compressed air connection to the interior of the working medium tank or for opening a venting channel from the interior of the working medium tank to an exhaust air outlet, through which the working medium space can be vented. According to the invention, it is proposed that the exhaust air outlet is formed by an air outlet device by means of which at least one air outlet property, such as air velocity, air pressure and / or oil content, can be changed.

Description

[0001] The invention relates to a hydrodynamic retarder with an air outlet device through which compressed air can be directed into the environment.

[0002] The design of such a hydrodynamic retarder is well known from the StdT (standard engine control system) and comprises a working fluid tank and a working fluid circuit connected to it, in which a working chamber formed by a rotor and a stator is located. A retarder essentially distinguishes between two operating states: non-braking mode and braking mode.

[0003] In non-braking operation, the working medium tank is filled with a working medium, in particular oil, up to a certain level, so that a working medium space and an air space are formed in the working medium tank.

[0004] When the retarder is switched to braking mode, compressed air is applied to the working medium tank, pumping the working medium into the working medium circuit. When the system is switched back to non-braking mode, the working medium tank is vented to the atmosphere, allowing the working medium to be pumped back into the working medium tank by the pumping action between the rotor and stator. The working medium tank is thus designed as a pressure tank that is emptied or filled depending on the air pressure.

[0005] With the help of the working fluid, torque is transferred from the bladed rotor to the bladed stator. When the working chamber is filled, the rotor and thus a shaft that is particularly fixed in rotation with the rotor, such as a propeller shaft or transmission output shaft indirectly connected to the wheels of a vehicle, are decelerated.

[0006] The retarder's rotor and stator form a toroidal working chamber, which is connected to a working fluid circuit with a working fluid tank via a duct system. The working chamber is vented via a venting system, allowing air to escape into the environment through a connection between the working chamber and the surrounding area. The working fluid tank is connected to a compressed air connection via a compressed air regulator comprising several valves.

[0007] To switch the retarder to braking mode, the working fluid tank must be pressurized with compressed air via the compressed air regulator, also known as the MRCU, and the working chamber must be vented. The air present in the working chamber is then discharged into the atmosphere via the profile venting system.

[0008] When the retarder is switched to non-braking mode, the working fluid tank must be vented and the working chamber ventilated. The working chamber is ventilated with ambient air via the profile ventilation system, as is well known from DE 10 2013 006 611 A1. The working fluid tank is vented to the environment via an oil separator and the MRCU. The oil separator is thus located between the working fluid tank and the environment. The connection to the environment can be released using the MRCU, the pressure control valve, as is known, for example, from DE 10 2019 134 843 A1.

[0009] The profile ventilation system and the oil separator are thus designed, as also known from CN105 697 749 A, to prevent the working medium, especially oil, from escaping into the environment. Especially when switching to non-braking mode, oil foam forms, which has a volume many times greater than that of the oil and thus quickly fills the air space in the working medium tank with oil foam or oil, while no oil is allowed to escape into the environment. To prevent this, different ducting systems between the working medium tank and the environment are known. For example, CN 105 697 602 A describes a ducting system with several separation chambers, which in turn have different structures.

[0010] As known from CN 105 697 601 A, the oil separator channels are cast into the tank cap as open channels. To close the channel, or even to maintain a channel path, an intermediate element, in this case a seal, is required between the tank cap and the tank support part.

[0011] The object of the invention is to further improve the air outlet during the venting of the working medium tank in a retarder.

[0012] 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.

[0013] A hydrodynamic retarder comprising a working medium tank, composed of a tank housing part and a tank cap, a pressure control valve for optionally connecting a compressed air connection to the interior of the working medium tank or for opening a venting channel from the interior of the working medium tank to an exhaust air outlet, via which the working medium space can be vented, is proposed.

[0014] According to the invention, it is proposed that the exhaust air outlet is formed by an air outlet device by means of which at least one air outlet property, such as air speed, air pressure and / or oil content, can be changed.

[0015] In one embodiment, the air outlet device may be a pipe section which, for example, has a constant or changing cross-section.

[0016] To further change the air outlet properties, impact elements can be arranged in the cross-section, on which residual oil in particular can be deposited.

[0017] Furthermore, the air outlet device can comprise a labyrinth and / or a filter element, wherein the filter element can be a flow element, a sintered metal element or a wire mesh.

[0018] The invention is explained below with reference to the figures. The figures show in detail: Fig. 1 Functional sketch of a retarder Fig. 2 air outlet device Fig. 3 Air outlet device with oil separator Fig. 4 Sectional view of air outlet device with oil separator

[0019] Fig. Figure 1 shows a functional diagram of the retarder 1, from which the essential functions of a retarder can be derived. The entire working medium circuit through the retarder 1 and the control system are shown. The retarder 1 essentially consists of its retarder housing, which is composed of several housing parts 2, 3, 15, and 16. The stator housing 3 and the tank housing part can also be designed as a single piece. The rotor 6 and the stator 7 are arranged between the rotor housing 2 and the stator housing 3. The working medium 9, oil, flows into the working chamber 14 between the rotor 6 and the stator 7 via the fill channel 12. The working medium 9 flows back into the working medium tank 4 via the return channel 13 via the heat exchanger 11.

[0020] As shown, the tank consists of tank housing part 15, tank cap 16, and at least one separating element 17 arranged between them. For additional functions within the tank, additional separating elements can be provided, but these are not shown. The illustrated separating element 17 is designed such that, among other things, it seals the gap between tank housing part 15 and tank cap 16 from the environment. A further function of the separating element 17, together with tank housing part 15 and / or tank cap 16, is to form subregions 18, 34 or channels 36 that are required for special functions.

[0021] The area of ​​the working medium tank 4 that can be filled with oil is the oil chamber 30, and the space above the oil level is the air chamber 31. An oil separator 18 is provided in the air chamber 31, which has a passage 29. The outlet of the oil separator 18 is connected to the pressure control unit 19 via a channel 20, 34, 36 and to a compressed air supply 32. These channels 20, 34, 36 can be used to pressurize the working medium tank for switching to braking mode and vent it after switching to non-braking mode.

[0022] Venting occurs through a corresponding valve circuit within the compressed air regulator 19. During venting, the air, which usually contains oil, flows through the passage duct 29 into the oil separation device 18, which can be designed in different ways. The oil separation device 18 can contain a labyrinth, baffle plates, and / or a cyclone, which are shaped in such a way that the oil content of the air is reduced. The air then flows through the duct 20, the compressed air regulator 19, and the exhaust air duct 21, either directly into the environment or, as shown here, the exhaust air is guided again through an exhaust air chamber 23 or duct in the working medium tank 4 and from there into the environment via the exhaust air outlet 22.

[0023] The exhaust air chamber 23 contributes to sound absorption, although further measures can be provided in the exhaust air outlet 22.

[0024] For further details see Fig. 1 will not be discussed further, as these are sufficiently known from the StdT.

[0025] Fig. Figure 2 shows a first embodiment of an air outlet device 35 according to the invention, which is designed here as a deflection pipe. The exhaust air passes via the pressure control valve 19 and the exhaust air duct 21 into the exhaust air chamber 23, which is a space in the working medium tank 4. The exhaust air chamber 23 is a chamber that has no connection to the air space 31 of the working medium tank 4. The exhaust air chamber 23 can, for example, be formed between the tank housing part 15, the separating element 17, and the tank cap 15. Alternatively, the exhaust air chamber 23 can be formed between the separating element 17 and the tank housing part 15 or the tank cap 15. In all three cases, the exhaust air chamber 23 establishes a connection between the exhaust air duct 21 and the exhaust air outlet 22.

[0026] Although the exhaust air 33 is passed through the oil separator 18, oil may be ejected at the exhaust air outlet, which must not come into contact with components in the drive train of the motor vehicle, which would fail prematurely if an oil film were present.

[0027] The air outlet device 35 thus has two essential functions: firstly, the exhaust air 33 can be directed to components for which the oil film is harmless, and secondly, the air outlet device 35 can be designed in such a way that it promotes the separation of the oil within the air outlet device 35. This can be surface finishes or coatings, but an additional filter 37 and deflectors can also be provided.

[0028] Fig. 3 and Fig. 4 show an alternative air outlet device 35 with oil separator and filter 37. From the Fig.In Figure 4, the cross-sectional view of the air outlet device 35 with oil separator shows that the exhaust air is redirected several times and passed through a filter 27 before being released into the environment. With this special design, the oil is collected in the air outlet device 35. Since this is usually very small, the maintenance intervals are very long.

[0029] An air outlet device 35 of this type can also be integrated into the working medium tank 4 or the exhaust air chamber 23. The filter material can be a flow element, a sintered metal element, or a wire mesh. List of reference symbols 1 retarder 2 rotor housings 3 starter housings 4 Working medium tank 5a, b camp 6 Rotor 7 Stator 8 Rotor shaft 9 Working medium 10 Housing separation 11 heat exchangers 12 filling channel 13 Return channel 14 Workspace 15 Tank support part 16 fuel caps 17 Separator 18 oil separators 19 compressed air regulators 20 ventilation duct 21 Exhaust air duct 22 Exhaust air outlet 23 Exhaust air chamber 24 lubrication channel 25 Bypass 26 Ventilation duct 27 Control 28 Exhaust valve 29 Entrance 30 Oil room 31 Airspace 32 compressed air connection 33 Exhaust air 35 Air outlet device 36 Oil collection area 37 filter element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 006 611 A1

[0008] DE 10 2019 134 843 A1

[0008] CN 105 697 749 A

[0009] CN 105 697 602 A

[0009] CN 105 697 601 A

[0010]

Claims

[1] Hydrodynamic retarder (1) comprising a working medium tank (4), composed of a tank housing part (15) and a tank cap (16), a pressure control valve (19) for selectively connecting a compressed air connection (32) to the interior of the working medium tank (4) or for opening a venting channel from the interior of the working medium tank (4) to an exhaust air outlet (22), via which the working medium space (4) can be vented, characterized by that the exhaust air outlet (22) is formed by an air outlet device (35) by means of which at least one air outlet property, such as air speed, air pressure and / or oil content, can be changed. [2] Hydrodynamic retarder (1) according to claim 1, characterized by that the air outlet device (35) is a pipe section. [3] Hydrodynamic retarder (1) according to claim 2, characterized by that the pipe section has a constant or changing cross-section. [4] Hydrodynamic retarder (1) according to claim 2 or 3, characterized by that impact elements are arranged in the cross-section. [5] Hydrodynamic retarder (1) according to claim 1, characterized by that the air outlet device (35) comprises a labyrinth. [6] Hydrodynamic retarder (1) according to claim 1, characterized by that the air outlet device (35) comprises a filter element. [7] Hydrodynamic retarder (1) according to claim 6, characterized by that the filter element is a flow element, a sintered metal element or a wire mesh.

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