Device for closing the air discharge passage of the working chamber of the retarder

Abstract

The invention relates to a device for closing a working chamber bleed channel of a retarder. The device for closing a bleed channel (15) is used to connect a working chamber (9) in a retarder (1) formed by a rotor (3) and a stator (4) and capable of being filled with a working medium with the surrounding environment. The device comprises a check valve (16) having a float body (17) and a float chamber (18) with a sealing plane (19), wherein the float body (17) is designed so that when the working medium and / or working medium foam is transported into the float chamber (18) via the bleed channel (15), the float body moves toward the sealing plane (19) from an open position to a closed position. The invention proposes that, viewed in the flow direction (A), a mechanism is provided between the working chamber (9) and the sealing plane (19) by means of which the density of the working medium foam can be changed.

Description

Technical Field

[0001] The invention relates to a device for closing a bleed channel in a retarder, wherein the bleed channel connects a working chamber to the surrounding environment. Background Art

[0002] Such a working chamber is, for example, a working chamber formed between a rotor and a stator of a retarder. However, it is also conceivable that it is any chamber that can be filled with oil, for example, an oil tank of a retarder.

[0003] When the retarder is switched to braking mode, compressed air is introduced into the oil tank, thereby squeezing the oil from the oil tank into the working chamber of the retarder. The contained air can escape from the working chamber via a channel whose opening ends in the center of the working chamber. Although the main part of the oil is forced into the circular flow of the annular structure in the cross section of the working chamber by the rotation of the rotor, this leads to the formation of oil foam in the center of the working chamber, which is transported out of the working chamber via the bleed channel. The oil foam has a lower density than liquid oil, so that the function of the device for closing the bleed channel (especially the non-return valve with a float body) no longer works and causes the oil foam to escape from the bleed channel into the surrounding environment.

[0004] When switching to the non-braking mode, the oil is transported or pumped back to the oil tank from the working chamber. This also causes foam formation, which is squeezed out of the pressure tank.

[0005] In particular, if a large amount of foam is formed, this can lead to a failure of the non-return valve, since the float of the non-return valve does not have sufficient buoyancy, so that the oil foams into the surrounding area.

[0006] Oil foaming occurs when the retarder oil is contaminated, for example by water, wrong / bad oil or undesired air supply (leakage).

[0007] DE 10 2013 006 611 A1 discloses a venting device with a non-return valve, which is connected to the center of the working chamber via a channel. An additional volume is provided upstream of the non-return valve. The increase in volume reduces the flow rate, which leads to an improved separation of the air portion and the working medium portion. In addition, an insert can be arranged in the channel, which extends into the channel and provides an increased surface, thereby improving the separation.

[0008] A bleed device for an oil tank is known from DE 10 2013 207 004 A1. In order to separate oil from air, a labyrinth is arranged upstream of a valve.

[0009] Another solution is proposed in DE 10 2012 002 039 A1. In this case, the air coming out of the oil tank is passed through a centrifugal separator. Summary of the invention

[0010] The object of the present invention is to provide a device for closing a venting channel which has an improved function so that no oil can enter the surroundings.

[0011] This object is achieved by the device according to the invention for closing a venting channel.

[0012] According to the present invention, a device for closing a deflation channel is proposed, which is configured to connect a working chamber in a retarder formed by a rotor and a stator and which can be filled with a working medium with the surrounding environment. The device comprises a check valve, which has a float body and a float chamber with a sealing plane, wherein the float body is designed such that when the working medium and / or working medium foam is conveyed into the float chamber via the deflation channel, the float body moves toward the sealing plane from an open position to a closed position.

[0013] In order to improve the functionality, it is proposed according to the invention that, viewed in the flow direction, means are provided between the working chamber and the sealing plane, by means of which the density of the working medium foam can be varied.

[0014] The change in the working medium foam is achieved by reducing the air content in the foam before it reaches the sealing plane, i.e. changing and / or destroying the foam structure. The freed air can then escape via the still open non-return valve. Furthermore, as soon as the working medium and / or the processed foam (with a higher density) accumulates in the float chamber and reaches a predeterminable level, the float body will move or float into the closed position at this point, so that the non-return valve is safely closed.

[0015] The non-return valve according to the invention, in particular the float body, is therefore designed in such a way that the float body is moved into the closed position when the working medium foam in the float chamber and the density of the working medium foam reach a definable level.

[0016] In different embodiments, the mechanism can be arranged in the deflation channel before and / or inside the float chamber. In this case, within the meaning of the present invention, the float chamber forms a partial section of the deflation channel.

[0017] These means can be, for example, wire meshes or screen elements. The wire mesh can be made of a wire braid with a mesh width of 4 mm to 10 mm. Here, in particular, a mesh width of 6 mm to 8 mm is preferred for retarder oil.

[0018] In a preferred embodiment, the wire mesh can be produced by deforming a multi-layer wire braid, wherein the individual wires of the wire braid are deformed to form a filter structure. In the sense of the present invention, a filter structure is to be understood as a structure in which the regular structure of the wire braid is modified into an irregular structure, which has an increased flow resistance for fluids such as oil and air-oil mixtures.

[0019] In one embodiment, the wire mesh may have a traversable area between 0.5% and 40%.Also, the wire mesh may be constructed of a stainless steel braid.

[0020] Furthermore, in one embodiment it can be provided that the means comprise movable parts, by means of which the foam structure of the working medium can be broken up or changed.

[0021] In order to assist in the destruction of the foam, the means can also include nozzles, by means of which the working medium can be injected into the ventilation channel.

[0022] Furthermore, it is advantageous if an oil separator is provided between the non-return valve and the surroundings.

[0023] The non-return valve and / or the mechanism can be composed of individual components which have to be assembled or produced by so-called additive manufacturing methods so that they form a unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is explained in more detail below with the aid of the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram showing an apparatus for closing a deflation passage;

[0026] Figure 2 An embodiment of the device is shown;

[0027] Figure 3 Wire mesh is shown;

[0028] Figure 4 The hydraulic circuit is shown with the associated working medium circuit. DETAILED DESCRIPTION

[0029] Figure 1 A schematic diagram of a device 2 for closing a bleed air channel is shown. The closing device 2 shown here comprises an oil separator 21 with a venting outlet 22 , a non-return valve 16 and a wire mesh 20 .

[0030] The closure device 2 comprises a non-return valve 16 which, due to its structural design, closes only when the buoyancy of the float body 17 is sufficiently great to move the float body towards the sealing plane 19 into the closed position.

[0031] Figure 2 A possible embodiment of the closure device 2 is shown, which corresponds essentially to Figure 1 The structure of the schematic diagram shown in .

[0032] If, for the braking mode, the working medium, in particular the retarder oil, is moved into the working chamber 9 of the retarder, the air contained in the retarder working chamber 9 must be allowed to escape. However, depending on the state of the oil, foam is formed in the working chamber 9 and is squeezed out of the working chamber via the bleed channel 15, the opening of which is located in the center of the working chamber. The sealing device 2 now has the task of preventing the oil from entering the surrounding environment. The prerequisite for this is that the density of the working medium and / or the working medium foam transported to the float chamber 18 is very high, so that the float body 17 in the float chamber 18 moves toward the sealing plane 19 from the open position to the closed position. According to the invention, the density of the oil foam is changed by passing the oil foam through the wire mesh 20, that is, the foam is destroyed or at least the foam is destroyed so that large foam bubbles are transformed into small foam bubbles.

[0033] For further safety, an oil separator 21 is further provided between the check valve 16 and the surrounding environment.

[0034] After switching the retarder into the non-braking mode, a negative pressure occurs in the working chamber, which causes the float body 17 to move into the open position in the float chamber and allows ambient air to enter the working chamber 9 through the bleeding channel 15 counter to the flow direction A.

[0035] In other embodiments not shown, in order to destroy the foam and / or reduce or shrink the bubbles, a nozzle can also or additionally be provided in the degassing channel 15, through which oil is injected into the channel, through which the bubbles are broken. Alternatively or additionally, a movable component that moves through the foam is also conceivable.

[0036] Figure 3 2 shows an embodiment of a wire mesh 20. The wire mesh consists of multiple layers of wire braids, which are stacked one on top of the other and reformed into the wire mesh 20 to form the filter structure presented. In order to achieve a good foam destruction effect, the wire braid should have a wire thickness of 0.01 mm to 1 mm, wherein the mesh width can be 4 mm to 10 mm.

[0037] The number of layers of the wire braid and the degree of modification to form a wire mesh with a filtering effect can be adapted to the retarder oil used, with a traversable area of ​​between 0.5% and 10% leading to the best results.

[0038] Figure 4Schematically shows a hydraulic circuit with an associated working medium circuit. The retarder 1 has a bladed rotor 3 and a bladed stator 4, wherein the bladed rotor 3 is driven by a drive system to be braked, such as a motor vehicle drive system, via a drive shaft 5. The rotor 3 and the stator 4 are accommodated in a retarder housing 6, which includes an interface for an external working medium circuit 2, in the present case an interface for an inlet 7, which is in a guided connection with a working chamber 9 via a working medium inlet 8, and the retarder housing also includes a first return 10 and a second return 11, which are in a working medium-guiding connection with the working chamber 9 via a first working medium outlet 12 and a second working medium outlet 13.

[0039] The working medium outlets 12 , 13 , the inlet 7 and the idle flow channel 24 connected to the idle flow pump 23 are connected to an oil tank (not shown here) which includes a heat exchanger.

[0040] Reference numerals list

[0041] 1 Retarder

[0042] 2. Close the device

[0043] 3 Rotor

[0044] 4 Stator

[0045] 5 Drive shaft

[0046] 6 Retarder housing

[0047] 7. Inflow

[0048] 8 Working medium inlet

[0049] 9 Working chamber

[0050] 10 First reflux section

[0051] 11 Second reflux section

[0052] 12 First working medium outlet

[0053] 13 Second working medium outlet

[0054] 14 Center

[0055] 15 Deflation channel

[0056] 16 Check valve

[0057] 17 Float body

[0058] 18 Float chamber

[0059] 19 Sealing plane

[0060] 20 Wire Mesh

[0061] 21 Oil separator

[0062] 22 Exhaust outlet

[0063] 23 Pump

[0064] 24 Idle Channel

[0065] A Flow direction

Claims

1. A device for closing a venting channel (15) for connecting a working chamber (9) in a retarder (1) formed by a rotor (3) and a stator (4) and capable of being filled with a working medium to the surrounding environment, the device comprising a non-return valve (16) having a float body (17) and a float chamber (18) with a sealing surface (19), wherein: The float body (17) is designed such that when working medium and / or working medium foam is conveyed into the float chamber (18) via the air release channel (15), the float body moves toward the sealing plane (19) from an open position to a closed position. It is characterized in that Viewed in the flow direction (A), a mechanism (20) is provided between the working chamber (9) and the sealing plane (19), by means of which the density of the working medium foam can be changed. Wherein, the mechanism (20) is a metal wire mesh, wherein the metal mesh has a traversable area between 0.5% and 40%, And wherein, the metal wire mesh is composed of stainless steel braid.

2. The device according to claim 1, It is characterized in that The float body (17) is designed to move the float body (17) into a closed position when the working medium foam and the density of the working medium foam in the float chamber (18) reach a definable level.

3. The device according to claim 1, It is characterized in that The mechanism (20) is arranged in the deflation channel before and / or inside the float chamber.

4. The device according to claim 1, It is characterized in that The wire mesh is made of a wire braid having a wire thickness of 0.01 mm to 1 mm and a mesh width of 4 mm to 10 mm.

5. The device according to claim 4, It is characterized in that The wire mesh is produced by deforming a multi-layered wire braid, wherein the individual wires of the wire braid are deformed to form a filter structure.

6. The device according to claim 2, It is characterized in that The mechanism comprises a movable part, by means of which the foam structure of the working medium can be broken up or changed.

7. The device according to claim 2, It is characterized in that The device comprises a nozzle, by means of which a working medium can be injected into the venting channel (15).

8. The device according to claim 1, It is characterized in that An oil separator (21) is arranged between the check valve (16) and the surrounding environment.

9. The device according to any one of claims 1 to 7, It is characterized in that The non-return valve (16) and / or the mechanism (20) are produced by a so-called additive manufacturing method.

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