Device with an air compressor and check valve

Abstract

Device (1), in particular for an air spring system, comprising a housing (15) in which an air compressor (16) is arranged, wherein a recess (2) is provided in the housing (15) in which a pneumatically actuated valve body (6) is movably arranged, and comprising a connecting element (5) which is arranged on the housing (15) and acts as a valve seat for the valve body (6), wherein an elastomer element (7) is arranged on the valve body (6) towards the connecting element (5), characterized in that the valve body (6) comprises several projections (8) which serve to guide the valve body (6) laterally in the housing (15).

Description

[0001] The invention relates to a device according to the preamble of claim 1.

[0002] Air compressors that draw air from the environment typically have a check valve. This type of pneumatic check valve seals an inlet line from an outlet line. The check valve essentially comprises a valve seat and a valve stem. A specific sealing geometry of the valve stem seals against a sealing surface of the valve seat. For improved sealing, the sealing surface of the valve seat is usually made of an elastomer. The stable sealing geometry of the valve stem presses into the elastomer, deforming it. This seals the inlet line from the outlet line, thus meeting the tightness requirements.

[0003] Such a check valve is used, for example, in air compressors for air suspension systems. These automotive air suspension systems generally have long downtimes, during which the air compressor must be immediately available upon startup and must not lose air pressure. With the valve seat design mentioned above, the air pressure on the valve tappet leads to the formation of an impression in the elastomer during extended downtimes, which is due to the sealing geometry of the valve tappet. One possible way to prevent this would be to use a harder elastomer. However, the necessary harder elastomer compounds cannot completely meet the required sealing properties.

[0004] With a movable valve stem, there is a risk that the valve stem will touch down next to the imprint created in the elastomer. This can be caused, for example, by vibrations or temperature fluctuations. As a result, the sealing geometry of the valve stem sits next to the imprint, resulting in immediate leakage. The check valve can no longer meet the required sealing requirements.

[0005] One way to prevent this would be to manufacture the dimensions of the valve tappet and valve seat more precisely. However, this leads to high manufacturing costs.

[0006] From DE 10 2006 016 317 A1 a compressor arrangement for generating compressed air is known, which has an intake opening for sucking in a pressure medium, wherein a valve unit with a closure element is provided in the intake opening, wherein a flange element is arranged on the intake opening, which serves as a valve seat for the closure element, wherein the closure element comprises a sealing element which seals on the sealing surface of the flange element.

[0007] Furthermore, from DE 10 2008 029 822 A1 a vacuum pump is known, having a flow opening in which a valve plate is arranged, wherein a connecting piece forms a valve seat for the valve plate and the valve plate has a sealing ring which seals the valve plate at the valve seat.

[0008] In addition, from DE 10 2014 105 684 A1 a rotary vane pump is known which comprises an inlet opening in which a check valve is arranged, wherein the inlet opening comprises a stop as a valve seat for the check valve and the check valve comprises an elastomer body which comes to rest on the stop.

[0009] The object of the invention is to provide an improved device with a check valve which ensures a reliable sealing function with wide manufacturing tolerances and a reliable guidance.

[0010] The problem underlying the invention is solved with the features of the independent patent claim.

[0011] A device is provided with a housing in which an air compressor is arranged. A recess is provided in the housing, in which a pneumatically actuated valve body is movably arranged. A connecting element is arranged on the housing and acts as a valve seat for the valve body. An elastomer element is arranged on the valve body toward the connecting element. The device preferably serves to supply air to an air spring system. The housing acts as a valve housing in the region of the recess.

[0012] Advantageously, by positioning the elastomer element on the valve body toward the connecting element, the otherwise disadvantageous formation of an impression in the elastomer sealing surface of a valve seat is completely avoided. The arrangement according to the invention ensures a high level of tightness throughout the entire service life of the check valve.

[0013] According to the invention, the valve body comprises a plurality of protrusions which serve to guide the valve body laterally in the housing. The protrusions are provided on the outer circumference of the valve body and are shaped such that they are aligned parallel to the side wall of the housing or the valve housing. As a result, an outer surface of the protrusions corresponds to the side wall of the housing. The protrusions preferably serve to support the valve body in the housing at the bottom. The protrusions are further shaped towards the bottom of the valve housing such that the protrusions support the valve body on the valve housing. The protrusions thus serve as guide means for the valve body in the valve housing.Advantageously, the formations and the valve body form an overall diameter that essentially corresponds to the diameter of the valve housing, with the core diameter of the valve body being significantly smaller than the diameter of the valve housing. The formations thus ensure secure movement of the valve body in the valve housing without the valve body tipping or wedging in the valve housing. The tolerance dimensions of the valve body and the valve housing can be designed with a wide range of dimensions for cost-effective production (clearance fit). It is particularly preferred that air flow over the valve body via the formations. The valve body is supported on the base of the valve housing by means of the formations, and the smaller core diameter enables air flow over the valve body.The check valve is therefore in an open position and allows air to be sucked in by the air compressor.

[0014] According to a preferred embodiment, an outlet channel leads from the recess to the air compressor. When the check valve is open, the air compressor draws in air from the environment, with the drawn-in air flowing over the valve body. Preferably, the connecting element forms an inlet channel, with the inlet channel particularly preferably being sealable from the outlet channel by means of the valve body with an elastomer element. When air is drawn in from the environment, air flows via the inlet channel to the outlet channel. The pneumatically actuated valve body is brought into the open position by the ambient pressure, with the valve body being supported by the guide means on the base of the valve housing. During operation of the air spring system, the internal pressure in the air compressor is greater than the ambient pressure, whereby the valve body is pressed against the connecting element.This places the valve body in the closed position at the valve seat. In this position, no air can escape from the outlet channel through the inlet channel into the atmosphere, and the check valve fulfills its sealing function.

[0015] According to a further preferred embodiment, the elastomer element is vulcanized or glued to the valve body. The elastomer element preferably has a raised portion on its outer circumference. The connecting element preferably has a flat sealing surface facing the valve body, with the elastomer element sealing against the sealing surface by means of the raised portion. Essentially, the elastomer element is cost-effectively connected to the valve body and, by means of its raised portion, forms a particularly pressure-tight seal against the sealing surface of the connecting element. The sealing function is achieved by the raised portion of the elastomer element together with the flat sealing surface of the connecting element, whereby the valve body can advantageously also move radially in the valve housing while still securely sealing against the valve seat. This means that there can be no compromises regarding the sealing requirements.

[0016] The device is used in an air suspension system of a motor vehicle with at least one air spring and pneumatic lines that connect the air spring to the device.

[0017] Further preferred embodiments of the invention emerge from the subclaims and the following description of embodiments with reference to the figures.

[0018] It shows Fig. 1 schematically shows an exemplary device, Fig. 2 an exemplary device in the area that acts as a check valve, and Fig. 3 an exemplary valve body.

[0019] In Fig. 1 schematically shows an exemplary device 1. Device 1 comprises a housing 15 in which an air compressor 16 is arranged. Housing 15 also has a cylindrical recess 2, so that the housing 15 acts as a valve housing. A pneumatically actuated valve body 6 is movably arranged in recess 2, with an elastomer element 7 being arranged on the valve body 6. Furthermore, a hollow cylindrical connecting element 5 is arranged on the housing 15 at the position of the recess 2, which connecting element acts as a valve seat and forms an inlet channel 4. An outlet channel 3 leads from recess 2 to the air compressor 16. Housing 15 can be designed as a one-piece pneumatic block which contains the air compressor 16 and comprises further components, such as pneumatic channels and pneumatic valves or electro-pneumatic valves.An electric motor for driving the air compressor 16, as well as an air dryer device, can be arranged on the housing 15. A control unit can be provided on the housing 16 to control the air compressor 16 and the electro-pneumatic valves.

[0020] Fig. 2 shows an exemplary device in the area that acts as a check valve. The check valve comprises a bore in the housing 15, so that the housing 15 forms a valve housing. By means of the bore, a bottom closure of the recess 2 in the housing 15 is realized, which is opposite the connecting element 5. From the bottom closure of the recess 2 leads an outlet channel 3, which can be designed, for example, as a through-bore in the housing, which leads to an intake chamber of the air compressor and therefore serves as an air supply line. On the other hand, the check valve comprises the connecting element 5, which is arranged at the position of the recess 2 on the corresponding outer surface of the housing 15. The connecting element 5 acts as a valve seat and forms an inlet channel 4, which serves to suck in air from the environment.Connecting element 5 has a flat sealing surface 10, which is exposed in the area of ​​the recess 2 and serves as a valve seat for the valve body 6. The check valve also includes the movable valve body 6 within the recess 2. The valve body 6 is pneumatically actuated, whereby the inlet channel 4 can be sealed from the outlet channel 3 by means of the valve body 6.

[0021] Valve body 6 has, on the one hand, a core diameter 12, which is significantly smaller than the diameter 11 of the recess 2. On the core diameter 12 or on the circumference of the valve body 6, a plurality of formations 8 are provided, which are shaped in the direction of the outlet channel 3 and along an inner side wall of the valve housing. Formations 8 are therefore designed such that they form an overall diameter of the valve body 6, which essentially corresponds to the diameter 11 of the valve housing. Formations 8 support the valve body 6 at the bottom of the recess 2, in which the valve body 6 can assume an open position. Consequently, air from the inlet channel 4 can flow past the core diameter 12 of the valve body 6 and thus reach the air compressor via the outlet channel 3. The tolerance dimensions of the overall diameter of the valve body 6 and the diameter 11 of the recess 2 can be designed broadly for the purpose of cost-effective production.Formations 8 act as guides to ensure the secure movement of valve body 6 in recess 2 without the valve body 6 tilting or jamming. As a result, valve body 6 and recess 2 can be designed for a cost-effective clearance fit.

[0022] On the valve body 6, the elastomer element 7 is arranged towards the connecting element 5, which is vulcanized or glued to the valve body 6. The elastomer element 7 essentially serves to seal the inlet channel 4 from the outlet channel 3. The diameter 13 of the elastomer element 7 is larger than the diameter 14 of the inlet channel 4. The elastomer element 7 also has a raised portion 9 on the outer circumference and a smaller raised portion at the center point. The sealing function of the check valve is fulfilled by the valve body 6 with the elastomer element 7 and by means of the raised portion 9, which rests against the sealing surface 10 of the connecting element 5. Independent of the radial movement of the valve body 6 within the valve seat 2, the sealing surface 10, together with the raised portion 9, ensures a constant sealing function.

[0023] The air compressor can be operated as part of an air suspension system in two ways, whereby the air compressor serves to fill at least one air spring or an air reservoir. In open air supply mode of the air compressor, air is sucked in from the environment via inlet channel 4 and fed to the air compressor via outlet channel 3. This fills the air spring or the air reservoir. In this case, the intake of the air compressor creates an ambient pressure which is higher than a negative pressure in the air suspension system. Because the ambient pressure is higher, the check valve is opened or the valve body 6 is pressed to the bottom of the valve housing. In this position, air can be sucked in by the air compressor, overflowing the valve body 6. In closed air supply mode, the air compressor feeds air from the air reservoir into the air spring or vice versa.The system pressure in the air spring system is higher than in the ambient air. This higher system pressure closes the check valve, or the valve body 6 with the elastomer element is pressed against the connecting element 5.

[0024] Fig. Figure 3 shows a perspective view of an exemplary valve body 6 with an elastomer element 7. Valve body 6 has a core diameter 12 that is significantly smaller than the diameter of the recess. This allows air to flow around the valve body 6 when the check valve is open. Core diameter 12 and the diameter of the elastomer element 7 are larger than the diameter of the inlet channel. Furthermore, the elastomer element 7 has an outer protrusion 9 and a smaller central protrusion. The outer protrusion 9 allows the elastomer element 7 to seal against the sealing surface of the valve seat when the check valve is closed. List of reference symbols 1 device 2 recess 3 output channels 4 input channels 5 connecting element 6 valve bodies 7 Elastomer element 8 Formation 9 Survey 10 Sealing surface 11 Diameter valve seat 12 core diameter valve body 13 diameter elastomer element 14 diameter input channel 15 housings 16 air compressors

Claims

[1] Device (1), in particular for an air spring system, with a housing (15) in which an air compressor (16) is arranged, wherein a recess (2) is provided in the housing (15) in which a pneumatically actuated valve body (6) is movably arranged, and with a connecting element (5) which is arranged on the housing (15) and acts as a valve seat for the valve body (6), wherein an elastomer element (7) is arranged on the valve body (6) towards the connecting element (5), characterized by that the valve body (6) comprises a plurality of formations (8) which serve to guide the valve body (6) laterally in the housing (15). [2] Device (1) according to claim 1, characterized by that the formations (8) serve to support the valve body (6) in the housing (15) at the bottom. [3] Device (1) according to claim 1 or 2, characterized by that the valve body (6) can be overflowed by means of the formations (8). [4] Device (1) according to one of claims 1 to 3, characterized by that an outlet channel (3) leads from the recess (2) to the air compressor (16). [5] Device (1) according to one of claims 1 to 4, characterized by that the connecting element (5) forms an input channel (4). [6] Device (1) according to claim 5, characterized by that the inlet channel (4) can be sealed against the outlet channel (3) by means of the valve body (6) with elastomer element (7). [7] Device (1) according to one of claims 1 to 6, characterized by that the elastomer element (7) is vulcanized or glued to the valve body (6). [8] Device (1) according to one of claims 1 to 7, characterized by that the elastomer element (7) has a raised portion (9) on its outer circumference. [9] Device (1) according to one of claims 1 to 8, characterized by that the connecting element (5) has a flat sealing surface (10) towards the valve body (6). [10] Device (1) according to claim 9, characterized by that the elastomer element (7) seals by means of the elevation (9) on the sealing surface (10). [11] Air spring system comprising at least one air spring and a device according to one of claims 1 to 10, as well as pneumatic lines which interconnect the air spring and the device.

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