Ventilation device

Abstract

The invention relates to a ventilation device for a drive assembly of a motor vehicle, comprising an air introduction device (2) having an air guide region (12) and being fluidically connectable to an interior (1) to be ventilated by means of the air guide region and comprising a membrane ventilator (6) having a ventilator membrane (7) which is permeable to water vapor in a first flow direction and impermeable to water vapor in a second flow direction, the membrane ventilator being at least temporarily fluidically connected to the air guide region, the ventilator membrane being arranged in an air guide housing such that it is impermeable to water vapor in an intake direction, an intake shut-off valve being arranged upstream of the ventilator membrane and upstream of the air guide region in the intake direction and by means of which a fluid flow from the air guide region to the ventilator membrane, i.e. a fluid flow against the intake direction, can be prevented.

Description

TECHNICAL FIELD

[0001] The invention relates to a ventilation device, in particular for a transmission in a motor vehicle. BACKGROUND

[0002] DE 102 015 214 923 A1 relates to a pressure equalizing element and a housing having such a pressure equalizing element.

[0003] In the following, the invention is explained by means of a ventilation device in a motor vehicle transmission, which is not to be understood as a restriction of the invention to this application. In a motor vehicle, a traction motor, i.e. a drive motor for providing driving power to overcome the travel resistance, is permanently or selectively coupled with drive wheels via a transmission. Irrespective of whether the transmission has a rigid gear ratio or is shiftable, the transmission is subjected to high temperature fluctuations, which necessitate a pressure equalization of the transmission interior with respect to the environment surrounding the transmission. In order to be able to realize such a pressure equalization, such a transmission has at least one ventilation device. The construction form of this ventilation device is a so-called membrane ventilator, wherein the membrane is water-impermeable but air-permeable, which has the working principle of so-called sportswear or functional clothing. In the transmission, there is a so-called aerosol, i.e. a mixture of air and fine lubricant droplets, in particular on the basis of movements of components in the transmission, such as movements of transmission shafts and gears. On passage of the air from the transmission interior, the lubricant droplets can deposit or or accumulate on the membrane, which is undesirable, since this can impair the functionality of the ventilation device. SUMMARY

[0004] It is an object of the invention to give a ventilation device having a ventilation membrane, which has an improved functional safety.

[0005] The object is achieved by a ventilation device for a drive assembly of a motor vehicle, the ventilation device comprising an air inlet device having an air guide region, the air inlet device being flow- conductively connectable to an interior to be ventilated via the air guide region, and the air inlet device comprising a membrane ventilator having a ventilator membrane which is permeable to water vapor in a first flow direction and impermeable to water vapor in a second flow direction, the membrane ventilator being at least temporarily flow-conductively connected to the air guide region, an intake direction being constituted by an imaginary flow direction through the ventilator membrane from an environment surrounding the ventilation device and pointing to the air guide region, and the ventilator membrane being arranged in an air guide housing such that it is impermeable to water vapor in the intake direction, an intake shut-off valve being arranged upstream of the ventilator membrane in the intake direction and upstream of the air guide region, and fluid flow from the air guide region to the ventilator membrane, i.e. fluid flow against the intake direction, being blocked by the intake shut-off valve, the ventilation device having an air outlet device having at least one air outlet opening via which air can be discharged to an environment surrounding the ventilation device, and the air outlet device having an air guide region, the air outlet device being flow-conductively connectable to the interior to be ventilated via the air guide region, and having a discharge direction in the air outlet device from the air guide region to the at least one air outlet opening, and a discharge shut-off valve being arranged upstream of the air outlet opening in the discharge direction and downstream of the air guide region, and fluid flow from the at least one air outlet opening to the air guide region, i.e. fluid flow against the discharge direction, being blocked by the discharge shut-off valve, the intake shut-off valve and the discharge shut-off valve having a common valve body which is movable between at least two end positions such that in a first end position flow in the air outlet device in the discharge direction is allowed and flow in the air inlet device in the intake direction is shut off, and in a second end position flow in the air inlet device in the intake direction is allowed and flow in the air outlet device in the discharge direction is shut off, a control chamber being connected to the interior to be ventilated by a control line, the valve body being pressed by means of a spring element into one end position such that flow from the interior to be ventilated via the air guide region through the air outlet opening is allowed, the valve body being moved into a position on the basis of a negative pressure in the control chamber if the pressure in the interior falls relative to the pressure in the environment during or after operation of the drive assembly, in which position the flow path through the air outlet device is shut off and the flow path through the air inlet device in the intake direction is released.

[0006] In the sense of the present application, a ventilation device can be understood as a device for effecting a pressure equalization between an interior arranged in a housing and an environment surrounding the housing. Preferably, the housing is a housing of a motor vehicle drive assembly, preferably a motor vehicle transmission or a drive motor and further preferably a drive electric motor. In particular, the motor vehicle drive assembly is at least partially filled with a fluid, preferably motor oil or transmission oil. In particular during operation of the motor vehicle drive assembly, a so-called aerosol is formed in the interior to be ventilated, in which the fluid is at least temporarily accommodated.

[0007] Herein, in the sense, an aerosol can be understood as air containing fine fluid droplets, preferably fine lubricant droplets. In a flow which typically occurs when pressure equalization is carried out for the interior, in the case of an overpressure in the interior relative to the environment surrounding the motor vehicle drive assembly, an aerosol flow from the interior to the environment is caused, such a (aerosol) flow carrying fine lubricant droplets.

[0008] Preferably, the ventilation device has at least one air introduction device, i.e. a device for effecting a pressure equalization between the environment surrounding the motor vehicle drive assembly and the interior of the motor vehicle drive assembly, in particular when a higher pressure exists in the environment than in the interior to be ventilated. Further preferably, the air introduction device is thus configured for effecting an air flow from the environment surrounding the motor vehicle drive assembly to the interior of the motor vehicle drive assembly. Further preferably, the ventilation device has, in addition to the air introduction device, an air removal device, both devices being arranged on the motor vehicle drive assembly separately in terms of location and thus can be configured as spatially separate devices and in another embodiment can preferably be integrated in one unitary or preferably multipart air introduction housing.

[0009] The air introduction device has, in particular, a so-called air guide region, through which the air introduction device is at least temporarily or permanently flow-conductively connected with the interior to be ventilated, in particular with the interior to be ventilated of a motor vehicle drive assembly. In addition, the air introduction device has a membrane ventilator. Preferably, the membrane ventilator is configured for reducing or preferably preventing moisture from entering into the interior to be ventilated via the air introduction device. The membrane ventilator has, in particular, for forming this functionality, a ventilator membrane. Such a ventilator membrane has at least substantially the working principle of a functional clothing having a water-repellent property that repels water from "outside" to "inside". Thus, the ventilator membrane is permeable to water or water vapor in a first flow direction and impermeable to water or water vapor in a second flow direction. In addition, the membrane ventilator is at least temporarily flow-conductively connected with the air guide region, such that at least for certain pressure conditions a pressure equalization between the interior to be ventilated and the environment surrounding the motor vehicle drive assembly is achieved.

[0010] In the sense of the present application, the intake direction can be understood as an imaginary flow direction from the environment surrounding the ventilation device through the ventilator membrane to the air guide region. In addition, the ventilator membrane is arranged in the air introduction housing such that it is impermeable to water vapor in the intake direction. In particular, by means of this arrangement of the ventilator membrane it is possible to prevent moisture from the environment from entering into the interior to be ventilated via the ventilation device.

[0011] The air introduction device has an intake shut-off valve, which is preferably configured as an intake check valve, by means of which a fluid flow through the valve in one flow direction is prevented and a fluid flow through the valve in the opposite direction is allowed. The intake shut-off valve is arranged downstream of the ventilator membrane and upstream of the air guide region in the intake direction. In addition, the intake shut-off valve is arranged or actuated here such that a fluid flow from the air guide region to the ventilator membrane, i.e. a fluid flow against the intake direction, is prevented by the intake shut-off valve. In particular, by means of this solution of the present application it is possible to prevent aerosols from the interior to be ventilated from reaching the ventilator membrane via the air guide region and thus to prevent a negative influence of the aerosols on the ventilator membrane and thus to improve the functional safety of the ventilation device.

[0012] Further preferably, in addition to the air introduction device, an air discharge device is provided, which achieves a pressure balance, in particular in the case where a higher pressure exists in the interior to be ventilated of the motor vehicle drive assembly than in the environment surrounding the ventilation device. In order to achieve, in particular, the aforementioned functionality, the air discharge device has at least one and preferably a plurality of air discharge openings. Preferably, such an air discharge opening constitutes a recess in the air discharge device, via which at least one air discharge opening it is possible for air to be discharged from the ventilation device to the environment surrounding the ventilation device, in other words the air discharge device is fluidically connected to the environment surrounding the air discharge device via the air discharge opening. In addition, the air discharge device has an air discharge region, via which the air discharge device can be fluidically connected to the interior to be ventilated. In the air discharge device, the imaginary flow direction is defined as the so-called exhaust direction, which points from the air discharge region to the at least one air discharge opening.

[0013] In addition, an exhaust cutoff valve is provided upstream of the air discharge opening in the exhaust direction and downstream of the air discharge region, which preferably constitutes an exhaust check valve. By means of such an exhaust cutoff valve, it is possible to block the flow of fluid in one direction in the air discharge device and to allow the flow of fluid in the other direction, which is opposite to the first direction. The exhaust cutoff valve is accommodated or actuated in the air discharge device in such a way that the flow of fluid from the at least one air discharge opening towards the air discharge region, i.e. against the exhaust direction, is blocked, and further preferably the flow of fluid through the exhaust cutoff valve in the exhaust direction is allowed.

[0014] In particular by means of this configuration of the ventilation device, the ventilation device has two paths for connecting the interior to be ventilated to the environment surrounding the ventilation device, in each of which paths (air introduction device, air discharge device) only one flow direction is allowed, and the flow directions in the two paths are opposite, so that as a result the ventilator membrane is not loaded with aerosol and a reliable pressure balance is achieved.

[0015] In a preferred embodiment, the air outlet region of the air outlet device and the air inlet region of the air inlet device are at least partially configured as a common region and, further preferably, they are integrated into a common air guide housing or are configured in the air guide housing or are arranged in the air guide housing as a common region. As described, based on the pressure conditions in the interior room to be ventilated, which is fluidically connected to the air outlet region and the air inlet region, and in the environment surrounding the ventilation device, an air flow through the ventilation device is generated, such that such a common region either functions as an air outlet region or as an air inlet region, in particular by means of such an integrated construction, a particularly space-saving construction of the ventilation device is achieved.

[0016] In a preferred embodiment, at least one of the shut-off valves, i.e. either the air inlet shut-off valve or the air outlet shut-off valve or preferably both, is configured as a so-called check valve, i.e. as an air inlet check valve or an air outlet check valve. In a further preferred embodiment, at least one of the shut-off valves is configured as a so-called mushroom valve. In this sense, a mushroom valve can be understood as a valve device which has a valve body which has an elastomer as a component or which is composed of an elastomer and which has a holding section by means of which the valve body is held relative to a valve seat. Furthermore, at least one flow-through opening can be closed by the valve body and, furthermore, the flow-through opening can be closed in such a way that a flow through the flow-through opening is only permitted in one flow direction and a flow in the other flow direction is prevented by the valve body. So-called mushroom valves are known from the prior art and have a high functional safety.

[0017] In a preferred embodiment, both devices, i.e. the air inlet device and the air outlet device, have a common valve body by means of which one flow path can be closed and the other flow path can be opened, respectively. In such an embodiment, the valve body can preferably be moved back and forth between a first end position and a second end position, wherein in the first end position a flow through the air inlet device in the air inlet direction is prevented and a flow through the air outlet device in the air outlet direction is permitted and in the other end position a flow through the air inlet device in the air inlet direction is permitted and a flow through the air outlet device in the air outlet direction is prevented. In other words, by means of the movable valve body, in the ventilation device it is achieved that when the valve body is in one of the end positions, a flow in the air outlet direction is permitted and a flow in the air inlet direction is shut off, and when the valve body is in the other end position, a flow in the air inlet direction is permitted and a flow in the air outlet direction is shut off. BRIEF DESCRIPTION OF DRAWINGS

[0018] The individual features and preferred embodiments of the application are explained in more detail below with the aid of the drawings, in which, in addition to the feature combinations shown, different feature combinations are also possible, the drawings being as follows:

[0019] Figure 1 schematic cross-sectional view of a first embodiment of a ventilation device;

[0020] Figure 2 schematic cross-sectional view of a second embodiment of a ventilation device;

[0021] Figure 3 schematic cross-sectional view of a third embodiment of a ventilation device. DETAILED DESCRIPTION

[0022] In Figure 1 the embodiment of the application described in the air inlet device 2 and the air outlet device 3 are structurally separate from one another, they guarantee the pressure balance of the inner room 1 to be ventilated relative to the environment surrounding the ventilation device. When the pressure in the environment is higher than the pressure in the inner room 1 to be ventilated, air flows through the air inlet guard 10 past the membrane ventilator 6 and through the ventilator membrane 7 in the membrane ventilator in the air inlet direction 14 through the air inlet device 2. The air inlet non-return valve 4 is installed in the air inlet device for controlling the flow through the air inlet device 2 such that a flow through the air inlet device is only possible in the air inlet direction 14 and a flow in the opposite direction is prevented. Aerosols, as they can be generated in the inner room 1 to be ventilated by the beating of components such as gears, although they can enter the air guide region 12 of the air inlet device 2, are prevented by the air inlet non-return valve 4 from flowing further to the membrane ventilator 6 with the ventilator membrane 7, so that the ventilator membrane is protected from being loaded with droplets of aerosol, in particular lubricant droplets.

[0023] In addition, the ventilation device has an air outlet device 3, through which a flow in the air outlet direction 13 is permitted and a flow against this direction through the air outlet non-return valve 5 is prevented. When there is an overpressure in the inner room 1 to be ventilated relative to the environment surrounding the ventilation device, air flows from this inner room 1 via the air outlet region 1 through the air outlet non-return valve 5 through the air outlet opening 8 and through the air outlet guard 9 out of the air outlet device 3.

[0024] Figure 2 In Figure 1 another embodiment of the ventilation device is described, in which below the differences to the embodiment described in

[0025] The air guiding area 12 and the air guiding out area are structurally merged with each other, so that the ventilation device is integrated in one common housing for ventilating the inner room 1, i.e. establishing a pressure balance with the environment surrounding the ventilation device. The air guiding out device 3 has an exhaust non-return valve 5, which allows a flow through the air guiding out device 3 in the exhaust direction 13, but prevents a flow against the exhaust direction.

[0026] The air guiding in device 2 has a membrane ventilator 6 with a ventilator membrane 7, which is protected from being loaded with aerosols by means of an intake non-return valve 4, because the intake non-return valve 4 allows a flow in the intake direction 14 and prevents a flow against the intake direction.

[0027] In Figure 3 a further embodiment of the ventilation device is described, wherein the ventilation device constitutes as an air pressure controlled intake stop valve with an exhaust stop valve integrated in the intake stop valve, which can also be understood as a valve with three ports and two switching positions, i.e. a two-position three-way reversing valve. Here, the control chamber 5a is connected with the inner room 1 to be ventilated by means of a control line. By means of a spring element, the valve body 4a is pressed into one end position, so that a flow from the inner room to be ventilated via the air guiding area 12 through the air guiding out opening 8 and the exhaust protection hood 9 is allowed, which here also constitutes jointly with the air guiding out area.

[0028] If the pressure in the inner room 1 drops relative to the pressure in the environment during or after the drive assembly operation, the valve body 4a is moved on the basis of the negative pressure in the control chamber into a position, in which the flow path through the air guiding out device 3 is shut off and the flow path in the intake direction 14 through the air guiding in device 2 is released. Here, a pressure loading of the valve body is possible, which differs from the described case. The intake stop valve and the exhaust stop valve work as a turnout in this embodiment, which releases one of the two possible flow paths and shuts off the second flow path.

[0029] List of reference signs

[0030] 1 inner room to be ventilated

[0031] 2 air guiding in device

[0032] 3 air guiding out device

[0033] 4 intake non-return valve

[0034] 4a valve body

[0035] 5 exhaust non-return valve

[0036] 5a control chamber

[0037] 6 membrane ventilator

[0038] 7 ventilator membrane

[0039] 8 air discharge opening

[0040] 9 exhaust protection cover

[0041] 10 intake protection cover

[0042] 11 air lead-out area

[0043] 12 air lead-in area

[0044] 13 exhaust direction

[0045] 14 intake direction

[0046] 15 pressure control line

Claims

1. A ventilation device for a motor vehicle drive assembly, the ventilation device comprising an air inlet device (2) having an air guiding region (12) the air inlet device (2) being directionally connected via the air guiding region to a chamber (1) to be ventilated, and the air inlet device comprising a diaphragm ventilator (6) having a ventilator diaphragm (7) permeable to water vapor in a first flow direction and impermeable to water vapor in a second flow direction, the diaphragm ventilator (6) being directionally connected at least temporarily to the air guiding region (12). The air intake direction (14) is formed by an imaginary flow direction from the environment surrounding the ventilation equipment through the ventilator diaphragm (7) and pointing towards the air guiding area (12). The ventilator diaphragm (7) is disposed in the air guiding housing such that water vapor cannot pass through the ventilator diaphragm in the air intake direction (14). An air intake shut-off valve is provided downstream of the ventilator diaphragm (7) and upstream of the air guiding area (12) in the air intake direction (14). The air intake shut-off valve prevents fluid flow from the air guiding area (12) to the ventilator diaphragm (7), i.e., fluid flow in the opposite direction to the air intake direction (14). The ventilation device has an air outlet device (3) having at least one air outlet opening (8) through which air can be discharged to the environment surrounding the ventilation device. The air outlet device (3) also has an air outlet area (11) through which it can be connected in a flow-directing manner to the interior room (1) to be ventilated. The air outlet device (3) has an exhaust direction (13) from the air outlet area (11) to the at least one air outlet opening (8). An exhaust shut-off valve is provided upstream of the air outlet opening (8) and downstream of the air outlet area (11) along this exhaust direction (13), preventing fluid flow from the at least one air outlet opening (8) to the air outlet area (11), i.e., fluid flow against the exhaust direction (13). Its features are, The intake shut-off valve and the exhaust shut-off valve share a common valve body (4a) that is movable between at least two end positions, such that in the first end position, flow in the air outlet device (3) in the exhaust direction (13) is permitted and flow in the air inlet device (2) in the intake direction (14) is stopped, and in the second end position, flow in the air inlet device (2) in the intake direction (14) is permitted and flow in the air outlet device (3) in the exhaust direction (13) is stopped. The control room (5a) is connected to the inner chamber (1) to be ventilated via a control pipe. By means of a spring element, the valve body (4a) is pressed to an end position, allowing flow from the inner chamber to be ventilated through the air guide area (12) and through the air exhaust opening (8). If the pressure in the inner chamber (1) drops relative to the pressure in the environment during or after the operation of the drive assembly, the valve body (4a) is moved to a position based on the negative pressure in the control chamber, where the flow path through the air outlet device (3) is cut off and the flow path through the air inlet device (2) is released in the air inlet direction (14).

2. The ventilation device for a motor vehicle drive assembly according to claim 1, characterized in that, The air outlet region (11) and the air guide region (12) at least partially constitute a common region, and the air outlet opening (8) is configured as a recess in the air inlet housing.

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