Hydrodynamic retarder

Abstract

The invention relates to a retarder comprising a retarder chamber in which a rotatably mounted rotor and a stator are arranged which together form a working chamber that can be filled with and emptied of working medium. The retarder also comprises: a working medium tank which has a region for holding working medium that is not currently in the working chamber; at least one filling channel for supplying working medium to the working chamber; and a return channel for discharging working medium from the working chamber, as well as a rotor housing, a stator housing, and a tank housing. According to the invention, the rotor housing and the tank housing enclose the retarder chamber and the working medium tank.

Description

[0001] Hydrodynamic retarder

[0002] The invention relates to the construction of a hydrodynamic retarder for a motor vehicle, in particular the construction of the housing of the retarder.

[0003] Hydrodynamic retarders have a working chamber that can be filled with a working fluid and emptied by it. The working fluid transfers torque from a bladed rotor to a 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.

[0004] The general structure of a retarder is known from DE 10 2017 109 014 A1, for example. This proposes a unit comprising a rotor mounted on a shaft, which is rotatably mounted relative to the unit on both sides of the rotor. The unit comprises a rotor housing, a stator housing, and a bearing bell. The unit, also called a rotor unit, is designed to be inserted into a housing.

[0005] A similar rotor unit or structural unit is known from DE 10 2012 002 038 A1, which is pre-assembled and inserted into a housing part. The housing part, together with a second housing part, forms a working medium tank. The working medium tank is connected to the retarder working chamber between the rotor and the stator via several channels. The housing parts comprise sections of channels for conveying the working medium, whereby the channels are only formed after the components have been assembled. The channels usually do not have closed walls, so additional components and seals are provided to form the actual channels. Furthermore, there are several large sealing planes between the components that must be sealed from the environment. When oil is used as the working medium, it is important that no oil can escape into the environment. The manufacturing effort for retarders manufactured in this way with a working medium tank is correspondingly complex and cost-intensive.

[0006] The object of the invention is to propose a retarder with reduced manufacturing and assembly costs.

[0007] 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.

[0008] A retarder is proposed, comprising a retarder chamber in which a rotatably mounted rotor and a stator are arranged, which together form a working chamber that can be filled with and emptied from the working chamber. The retarder further comprises a working-medium tank, which has a region for receiving working medium not currently present in the working chamber and an expansion region, at least one filling channel for supplying working medium into the working chamber and a return channel for discharging working medium from the working chamber, as well as a rotor housing, a stator housing, and a tank housing.

[0009] According to the invention, the rotor housing and the tank housing form the working medium tank, and the retarder chamber is a space enclosed by the rotor housing and the stator housing, with a coupling plane between the rotor housing and the stator housing being arranged within the working medium tank. For the purposes of the invention, this means that, in particular, the rotor, the stator, as well as the filling channel and the return channel, are located within the space formed by the rotor housing and the tank housing.

[0010] In a preferred embodiment, the retarder chamber can be a space formed by the rotor housing and a stator housing, with the stator being arranged between the rotor housing and the stator housing. The stator housing is arranged entirely within the space formed by the rotor housing and the tank housing. The rotor, which is arranged on a rotor shaft, is preferably supported by a first bearing relative to the rotor housing and a second bearing relative to the stator or the stator housing.

[0011] The internal contact surfaces, e.g., the surfaces between the rotor housing, stator, and stator housing, can form functional planes, whereby no seal is required in the functional plane. In the event of a minor leak in the functional plane, the working fluid flows directly back into the working fluid reservoir.

[0012] This design decouples the actual retarder function from the sealing function against the environment, and only a large-area seal is required, whereby no further functions need to be ensured via the seal arranged between the components.

[0013] Furthermore, it can be provided that the rotor housing and the tank housing are bowl-shaped, with a seal arranged between the rotor housing and the tank housing. The sealing surfaces on the rotor housing and the tank housing are easy to manufacture, so that a reliable seal of the working medium tank from the environment can be provided relatively easily.

[0014] Furthermore, a coupling plane can be provided on the tank housing, which has a first channel and a second channel, through which a fluid-conducting connection to the primary side of a heat exchanger can be established. This coupling plane can also be easily sealed. An intermediate component with intermediate channels can be arranged between the heat exchanger and the tank housing. Alternatively, the channels can be provided at different coupling planes on the tank housing.

[0015] It is also proposed that the return channel be designed as a fluid-conducting connection between the working chamber and the supply channel, wherein the return channel can be integrated at least partially into the stator housing. Alternatively, a pipe connection could be provided. Furthermore, an inlet chamber can be arranged between the filling channel and the working chamber, wherein the inlet chamber is a space formed between the stator and stator housing components.

[0016] In the preferred embodiment, the working medium tank has an expansion region, a storage region, and a sump region. The filling channel is designed as a pipeline that essentially runs through the working medium tank, with an inlet opening of the filling channel ending in the sump region. This prevents air from entering the working chamber via the filling channel when the retarder is switched to braking mode.

[0017] Preferably, the inlet opening into the filling channel and an outlet opening of the return channel are aligned with each other. It is advantageous if the distance (x) between the inlet opening and the outlet opening is between 1 mm and 25 mm.

[0018] The invention is explained in more detail below with reference to figures:

[0019] Figure 1 Sketch of a retarder in section

[0020] Figure 1 shows a sketch illustrating the basic housing structure of the retarder 1. The outer shell of the retarder 1 essentially consists of two parts: the rotor housing 2 and the stator housing 3, each of which forms a half-shell of the housing. The housing parts 2 and 3 enclose a cavity, which is divided into three sections. A cavity section 27, a storage section 26, and a retarder section 28 are provided.

[0021] The cavity area 27, the storage area 26 and the sump area 25 together form the working medium tank 15, wherein the working medium 9 collects in the storage area 26 and sump area 25 when the retarder is switched to non-braking mode.

[0022] The cavity area 27 is a space essentially designed to ensure that no working fluid can enter the compressed air control unit, also known as the MRCU, via port 17. A working fluid separator or oil separator 28 is provided between port 17 and the working fluid tank 15. Separating oil can flow back into the working fluid tank 15 via the drain 30.

[0023] During braking operation, the compressed air control regulates the braking torque of the retarder 1. The higher the air pressure in the cavity area 27, the more working medium 9 is pressed from the working medium tank 15 into the retarder circuit.

[0024] The area between the rotor housing 2 and the stator housing 3 is referred to as the retarder area 28. The rotor 6, the stator 7, the mounted rotor shaft 8, and channels for conveying the working fluid are located in the retarder area 28. The rotor 6 can be arranged axially displaceably on the rotor shaft 8, as is known from the prior art.

[0025] The bearing of the rotor shaft 8, on which the rotor 6 is arranged in a rotationally fixed manner, is carried out as shown in Figure 1 via a first bearing 5a opposite the rotor housing and via a second bearing 5b opposite the stator housing 3. Another solution not shown is a bearing opposite the stator 7. In this solution, a bearing ring is provided on the stator 7, in which the outer ring of the bearing 5b is received, so that there is only one coupling point opposite the rotor housing.

[0026] A coupling plane 18 is provided on the tank housing 4, to which a heat exchanger 11 can be attached directly or indirectly, wherein a first channel 19 and a second channel 20 are provided in the coupling plane 18. The working chamber 14, between the rotor 6 and stator 7, is connected to the flow connection of the heat exchanger 11 via the first channel 19, and the outlet of the heat exchanger 11 is connected to the working medium tank 15 via the second channel 20. The cooled working medium 9 enters the working medium tank 15 via the second channel 20 when switching to non-braking mode, i.e. when the pressure in the expansion region 27 drops. Furthermore, a filling channel 12 is provided, which establishes a connection from the lower sump region 25 to the inlet chamber 23, which in turn is connected to the working chamber 14 via channels in the stator 7, not shown.

[0027] When the retarder is switched to braking mode, the air pressure in the expansion area 27 is increased via connection 17, causing the working fluid 9 to flow into the working chamber 14 via the filling channel 12, the inlet chamber 23, and the channels in the stator 7. The known pumping action of the retarder 1 causes the working fluid 9 to be pumped back from the working chamber via the return channel 13, the first channel 19, the heat exchanger 11, and the second channel 20 into the working fluid tank 15.

[0028] The filling channel 12 is arranged relative to the second channel 20 such that working medium 9 flowing out of the second channel 20 can flow into the filling channel 12 via the inlet opening 21. During braking, this creates a circular flow, with the working medium 9 flowing through the working medium tank 15 over a short section. The distance between the outlet from the second channel 20 and the inlet opening 21 can be selected between 1 mm and 25 mm, with the mixing of working medium 9 from the tank and working medium 9 from the circuit depending on the distance. Furthermore, the minimum working medium level in the working medium tank 15 must be above the inlet opening 21 to ensure that no air enters the filling channel 12.

[0029] The pressure of the control air in expansion zone 27 regulates the working fluid volume in the circuit, which in turn determines the retarder's braking torque. This braking torque control is standard and will therefore not be described in detail.

[0030] Essential to this invention is the housing design of the retarder 1, which ensures that the surfaces of the functional planes 16, 24a, 24b are not simultaneously sealing surfaces against the environment. Functional planes 16, 24a, 24b are planes that are crucial for the function of the retarder. Opposite surfaces of a functional plane 16, 24a, 24b are subject to tight tolerances. Compliance with tolerances is significantly simplified if minor leaks are irrelevant due to the elimination of a seal.

[0031] All functional levels 16, 24a, 24b are located within the retarder housing parts 2 and 4, so that escaping oil from the retarder chamber 29 flows directly back into the

[0032] The working medium tank 15 is sealed against the environment by means of the seal 10, whereby parts 2 and 4 only function relative to each other and have no influence on the retarder function. As an alternative to the illustrated sealing arrangement of the working chamber 14, two O-rings 34 can be provided instead of the seal 10, with one O-ring sealing radially and one O-ring sealing axially. The tolerance requirements for such a design would be significantly lower.

[0033] List of reference symbols

[0034] 1 retarder

[0035] 2 rotor housings

[0036] 3 starter housings

[0037] 4 tank housings

[0038] 5a, b camp

[0039] 6 Rotor

[0040] 7 Stator

[0041] 8 Rotor shaft

[0042] 9 Working medium

[0043] 10 Seal

[0044] 11 heat exchangers

[0045] 12 filling channel

[0046] 13 Return channel

[0047] 14 Workspace

[0048] 15 Working medium tank

[0049] 16 coupling level

[0050] 17 Connection

[0051] 18 connection level

[0052] 19 first channel

[0053] 20 second channel

[0054] 21 Entrance opening

[0055] 22 Exit opening

[0056] 23 Inlet chamber

[0057] 24a, b coupling level

[0058] 25 Swamp area

[0059] 26 Storage area

[0060] 27 Expansion area

[0061] 28 oil separators

[0062] 29 Retarder room

[0063] 30 Process

[0064] 31 Structural element

[0065] 32 air passage

[0066] X distance

Claims

Patent claims 1. Hydrodynamic retarder (1), comprising a retarder chamber (29) in which a rotatably mounted rotor (6) and a stator (7) are arranged, which together form a working chamber (14) that can be filled with and emptied from the working chamber; a working medium tank (15) that has an area (25, 26) for receiving working medium not currently in the working chamber (14) and an expansion area (27); at least one filling channel (12) for supplying working medium into the working chamber (14); and a return channel (13) for discharging working medium from the working chamber (14);and a rotor housing (2), a stator housing (3) and a tank housing (4), characterized in that the rotor housing (2) and the tank housing (4) form the working medium tank (15) and the retarder space (29) is a space which is enclosed by the rotor housing (2) and the stator housing (3), wherein the coupling planes (24a, b) between the rotor housing (2) and the stator housing (3) are arranged within the working medium tank (15)..; 2. Hydrodynamic retarder (1) according to claim 1, characterized in that the rotor housing (2) and the tank housing (4) are shell-shaped and a seal (10) is arranged between the rotor housing and the tank housing.

3. Hydrodynamic retarder (1) according to claim 1, characterized in that the retarder space (29) is a space formed by the rotor housing (2) and a stator housing (3), the stator (7) being arranged between the rotor housing (2) and the stator housing (3).

4. Hydrodynamic retarder (1) according to claim 3, characterized in that the bearing of the rotor (6) arranged on a rotor shaft (8) takes place via a first bearing 5a opposite the rotor housing and via a second bearing (5b) opposite the stator (7) or stator housing (3).

5. Hydrodynamic retarder (1) according to claim 1, characterized in that a coupling plane (18) is provided on the tank housing (4), which has a first channel (19) and a second channel (20), wherein a fluid-conducting connection with the primary side of a heat exchanger is established via the channels (19, 20). (11 ) can be produced.

6. Hydrodynamic retarder (1) according to claim 2, characterized in that the return channel (13) establishes a fluid-conducting connection between the working chamber (14) and the first channel (19), wherein the return channel (13) is at least partially integrated in the stator housing (3).

7. Hydrodynamic retarder (1) according to claim 2, characterized in that an inlet chamber (23) is arranged between the filling channel (12) and the working chamber (14), wherein the inlet chamber (23) is a space which is formed between the components stator (7) and stator housing (3).

8. Hydrodynamic retarder (1) according to claim 1, characterized in that the working medium tank (15) has an expansion area (27), a storage area (26) and a sump area (25), wherein the filling channel (12) is designed as a pipeline which essentially leads through the working medium tank (15) and an inlet opening (21) of the filling channel (12) ends in the sump area (25).

9. Hydrodynamic retarder (1) according to claim 5, characterized in that the inlet opening (21) into the filling channel (12) and an outlet opening (22) of the return channel (20) are aligned with each other.

10. Hydrodynamic retarder (1) according to claim 9, characterized in that the distance (x) between the inlet opening (21) and the outlet opening (22) is between 1 mm and 25 mm.

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