Heat exchanger coupling with a retarder housing

Abstract

The proposed hydrodynamic retarder comprises a housing consisting of a retarder body and a tank lid, with a tank and oil channels integrated within the housing. A heat exchanger with primary and secondary connections is coupled to a coupling plane on the tank lid, via which the primary connections of the heat exchanger can be fluidly connected to the oil channels of a working fluid circuit. According to the invention, a connecting piece is provided, wherein the connecting piece forms a channel from the coupling plane through the housing, via which one of the secondary-side connections of the heat exchanger is fluidly connected to a cooling circuit of the motor vehicle.

Description

[0001] The invention relates to a hydrodynamic retarder, in particular an oil retarder, with a heat exchanger mounted on the retarder housing for a motor vehicle.

[0002] Most motor vehicles such as trucks or buses are equipped with a retarder, an additional continuous braking device, to reduce wear on the vehicle's conventional wheel brakes. Such an additional brake can be a primary or secondary retarder. In both versions, the retarder rotor is coupled or can be coupled to the drivetrain. Furthermore, a device is provided by which the retarder can be filled with a working fluid for braking operation. When the working chamber is filled and the rotor is rotating, a braking torque acts on the rotor.

[0003] The hydraulic circuit for such a retarder is known, for example, from DE 10 2013 006 611 A1. The retarder disclosed here uses oil as the working medium, which is provided in a substantially closed circuit. Integrated into the circuit is the primary side of a heat exchanger, which is used to dissipate the retarder's waste heat when the retarder is switched to braking mode. The secondary side of the heat exchanger is connected to the vehicle cooling circuit, which also cools the vehicle's combustion engine.

[0004] The typical layout of a secondary retarder can be found in DE 10 2014 215 861 A1. The heat exchanger, mounted directly on the retarder, is fluidly connected to the working fluid circuit, the oil circuit, on the primary side, and to the cooling water circuit of the vehicle on the secondary side.

[0005] Due to the limited installation space in most motor vehicles, some applications encounter problems with the pipe or hose routing from the heat exchanger to the vehicle's cooling water circuit. This leads to considerable additional planning and implementation effort for the retarder and heat exchanger in the vehicle.

[0006] DE 10 2019 134 062 A1 discloses an alternative fluid-conducting connection between the secondary side of the heat exchanger and a motor vehicle cooling circuit. In this case, in addition to the connection for the oil circuit, the connection for the cooling water circuit is also made via the coupling plane. By directly coupling all fluid-conducting connections between the retarder and the heat exchanger via the coupling plane on the retarder housing, the design is significantly simplified and the hose connectors on the heat exchanger can be eliminated, thus improving the installation conditions in the heat exchanger area.

[0007] Another retarder design is known from CN1 08 533 643 A. To reduce the axial installation space, the water nozzles of the heat exchanger are routed through recesses on the side of the retarder housing or through the retarder housing.

[0008] DE 10 2012 002 038 A1 discloses another design for a retarder housing, to which a heat exchanger is mounted. A coupling plane is provided between the heat exchanger and the retarder housing. However, separating the fluids of the oil and water circuits requires significant manufacturing and assembly effort to ensure reliable separation of the fluids during retarder operation.

[0009] The object of the invention is to propose a retarder unit with an attached heat exchanger, which represents an improvement over the StdT.

[0010] The object is achieved according to the invention by an embodiment according to independent claim 1. Further advantageous embodiments of the present invention can be found in the subclaims.

[0011] The proposed hydrodynamic retarder comprises a housing composed of a retarder housing and a tank cap, with a tank and oil channels integrated into the housing. A heat exchanger with primary and secondary side connections is coupled to a coupling plane on the tank cap, via which the primary side connections of the heat exchanger can be fluidly connected to the oil channels of a working medium circuit.

[0012] According to the invention, a connecting piece is provided, wherein the connecting piece forms a channel from the coupling plane through the housing, via which one of the secondary-side connections of the heat exchanger is fluidly connected to a cooling circuit of the motor vehicle. This design ensures that all heat exchanger connections are located in the coupling plane, and the connection of the heat exchanger to the cooling water circuit can be established on the drive side of the retarder.

[0013] Preferably, the connecting piece runs within the housing through a space sealed from the tank and the oil channels. In a preferred embodiment, the space is formed by the tank cap, the retarder housing, and a seal arranged between them. This design allows for thermal separation of the oil circuit and the cooling water circuit and prevents cooling water from entering the oil circuit.

[0014] The connecting piece can be guided through an opening in the retarder housing and an opening in the tank cap, so that axial length compensation between the components is possible.

[0015] For sealing, a radial sealing element can be provided between the tank cap and the connecting piece. Furthermore, an axial sealing element can be arranged between the tank cap and the heat exchanger. These seals prevent cooling water loss into the environment and the room.

[0016] Furthermore, a cooling water connection which is fastened to the retarder housing can be provided, wherein the connecting piece in this embodiment is arranged between the heat exchanger and the cooling water connection, so that an axial length compensation between the components is possible.

[0017] The invention is explained below with reference to the figures. The figures show in detail: Fig. 1 Heat exchanger connection through the retarder housing in section Fig. 2 Section AA through tank cap

[0018] Fig. 1 shows a section through the retarder housing of the heat exchanger connection. The sketched section illustrates an exemplary embodiment showing the connection between one of the secondary-side connections 15 of the heat exchanger 11 and the cooling circuit. The heat exchanger 11 is attached to the coupling plane 14 on the tank cap 2 in such a way that fluid-conducting connections are formed between the retarder 1 and the primary side of the heat exchanger 11 for the passage of the working medium, in particular oil. Furthermore, at least one further fluid-conducting connection is provided in the coupling plane 14, via which the secondary circuit of the heat exchanger 11 can be connected to a cooling circuit (not shown here).

[0019] This connection is made via a connecting piece 6, which passes through the housing 16 of the retarder 1. The connecting piece 6, here a pipe, is guided through an opening in the tank cap 2 and an opening in the retarder housing 3, thus enabling axial length compensation or axial movement of the connecting piece 6 with respect to the components 2, 3. Two sealing planes are provided on the side of the coupling plane 14. By means of the sealing element 12 in the coupling plane 14, a seal is achieved between the channel 17 and the environment, so that no cooling water escapes into the environment. Furthermore, a radially arranged sealing element 13a is provided between the connecting element 6 and the tank cap 2, which prevents cooling water from penetrating the housing 16.

[0020] On the retarder housing side, no seal is provided between the retarder housing 3 and the connecting piece 6. The sealing element 13b is provided here between the connecting piece 6 and the cooling water connection 4, which is attached to the retarder housing 3 and has a stop to limit axial movement of the connecting piece 6. The connecting piece 6 is thus mounted between the heat exchanger 11 and the cooling water connection 4 in such a way that axial length compensation can occur. The sealing of the channel 17 occurs only between the connecting piece and the cooling water connection 4, by means of the seal 13b. An annular gap can be provided between the retarder housing 3 and the connecting piece 6, since the centering of the connecting piece 6 is achieved solely by centering in the cooling water connection 4. Therefore, no separate sealing element is present or necessary between the chamber 5 and the surrounding area.

[0021] The space 5 through which the connecting piece 6 passes is, as in Fig. 2, a separate area in housing 16. This space is sealed off from the tank 8. The space 5 is thus formed by the tank cap 2, the retarder housing 3, and the seal 10 arranged between them. This design ensures thermal separation between the oil circuit and the cooling water circuit. Furthermore, it ensures that no cooling water can enter the oil circuit. List of reference symbols 1 retarder 2 fuel caps 3 retarder housing 4 Cooling water connection 5 rooms 6 connecting piece 7 Riser channel 8 tanks 9 riser cover 10 Seal 11 heat exchangers 12 Seal 13a,b Seal 14 coupling level 15 Connection 16 housings 17 Channel

Claims

[1] Hydrodynamic retarder (1) for a motor vehicle, comprising a housing (16) composed of a retarder housing (3) and a tank cap (2), in which a tank (8) and oil channels (7) are integrated, and a heat exchanger (11) with primary-side connections and secondary-side connections (15), wherein a coupling plane (14) is provided on the tank cap (2), via which the primary-side connections of the heat exchanger (11) can be connected in a fluid-conducting manner to the oil channels (7) of a working medium circuit, characterized by that a connecting piece (6) is provided, wherein the connecting piece (6) forms a channel (17) from the coupling plane (14) through the housing (16), via which channel one of the secondary-side connections (15) of the heat exchanger (11) is fluidly connected to a cooling circuit of the motor vehicle. [2] Hydrodynamic retarder (1) according to claim 1, characterized bythat the connecting piece (6) runs inside the housing (16) through a space (5) sealed off from the tank (8) and the oil channels (7). [3] Hydrodynamic retarder (1) according to claim 2, characterized by that the space (5) is formed by the tank cap (2), the retarder housing (3) and a seal (10) arranged therebetween. [4] Hydrodynamic retarder (1) according to claim 1, characterized by that the connecting piece (6) is guided through an opening in the retarder housing (3) and an opening in the tank cap (2), so that an axial length compensation between the components (2, 3, 6) is possible. [5] Hydrodynamic retarder (1) according to claim 1, characterized by that a radial sealing element (13) is provided between the tank cap (2) and the connecting piece (6). [6] Hydrodynamic retarder (1) according to claim 1, characterized by that an axial sealing element (12) is arranged between the tank cap (2) and the heat exchanger (11). [7] Hydrodynamic retarder (1) according to claim 1, characterized by that the connecting piece (6) has a connecting section (17) which protrudes from the retarder housing (3). [8] Hydrodynamic retarder (1) according to claim 1, characterized by that a cooling water connection (4) is provided on the retarder housing (3), wherein the connecting piece (6) is arranged between the heat exchanger (11) and the cooling water connection (4), so that an axial length compensation between the components (2, 3, 6) is possible.

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