DE102017206360A1 - Housing for a pneumatic control unit and pneumatic control unit - Google Patents

Abstract

The invention relates to a housing (10) for a pneumatic control unit (1) which comprises two housing main walls (11, 12) and the housing main walls (11, 12) connecting housing end walls (13, 14) which together form a receiving space (30 ) for receiving a valve unit (20) limit. The housing (10) further comprises a connection element (15) in a housing end wall (14) for pneumatic and electrical connection of the valve unit (20), wherein the two opposite housing main walls (11, 12) are mechanically connected to the connection element (15). At least one of the housing main walls (11, 12) is designed as a Helmholtz resonator and / or at least partially provided with a material weakening.

Description

The invention relates to a housing for a pneumatic control unit. The housing comprises two mutually opposite housing main walls and the housing main walls connecting housing end walls, which together define a receiving space for receiving a valve unit. For pneumatic and electrical connection of the valve unit at least one connecting element is provided in one of the housing end walls, wherein the two opposite housing main walls are mechanically rigidly connected to the connecting element.

In vehicles, pneumatic actuators are used e.g. used to adjust a seat geometry. One or more pneumatic actuators in the form of respective valves are installed in a pneumatic control unit. The valves generate noises during the opening and closing process. These noises occur when switching the valve, when flowing through the valve with air and a pressure surge occurring during switching. These noises are transmitted, among other things, as structure-borne noise to a housing of the pneumatic control unit. Finally, the sounds are audibly emitted as airborne sound for the occupants of the vehicle. Such sounds are undesirable because they can be perceived by customers of the vehicle as disturbing.

It is an object of the invention to provide a housing for a pneumatic control device, in particular for use in a vehicle, which emits lower sound than conventional control devices upon actuation of the pneumatic actuators received in the housing.

This object is achieved by a housing according to the features of claim 1. Advantageous embodiments will be apparent from the dependent claims.

It is proposed a housing for a pneumatic control unit, which comprises two mutually opposite housing main walls and the housing main walls connecting housing end walls. The two opposite housing main walls and the housing end walls together define a receiving space, which is provided for receiving a valve unit. The housing further comprises in one of the housing end walls a connection element for pneumatic and electrical connection of the valve unit. The two opposite housing main walls are mechanically connected to the connection element. According to the invention, at least one of the housing main walls is designed as a Helmholtz resonator and / or at least partially provided with a material weakening.

Such a housing radiates less structure-borne noise than a conventional housing. As a result, the audible for an occupant noise when the pneumatic control unit is installed in a vehicle, perceived only attenuated. At the same time, the proposed housing can be produced in a simple and cost-effective manner. Known manufacturing processes do not have to be modified at best or at best.

In an expedient embodiment, the at least one of the housing main walls can be provided with one or more holes. Depending on the position of the valve arrangement in the interior of the receiving space, it may be expedient to provide in each case one or more holes on the two opposite housing main walls. In addition, it can also be provided to additionally provide one or more of the housing end walls with one or more holes.

Depending on the volume remaining in the receiving space, if the valve unit is arranged in the receiving space, the hole area may be determined such that the frequency of the Helmholtz resonator is greater than 1 kHz, in particular greater than 3 kHz. Preferably, a frequency of 5 kHz or more is desired. The hole area is understood to be the sum of all surfaces of all holes provided in the housing. The hole area can be realized by a large number of small holes or a comparatively smaller number of larger holes. It is not necessary that all holes have the same size and / or shape. Rather, different hole sizes and hole shapes can be combined with each other in a respective housing main wall or housing end wall. The holes can be arranged regularly or irregularly distributed over the respective housing surfaces.

The provision of one or more holes results in an acoustic short circuit between the receiving space and the outer of the housing. This allows pressure equalization to be established between the interior of the receiving space (i.e., the housing interior) and the exterior of the housing. As a result, a sound radiation of the housing can be reduced.

In an alternative or additional embodiment, the at least one of the housing main walls is provided with an air- and sound-permeable sintered plate, which is inserted into a recess of the relevant housing main wall. Such a sintered plate may be made of a plastic, For example, PE (polyethylene), PP (polypropylene), or the like exist. Particularly preferably, the sintered plate consists of the material of the housing. This makes it possible to connect the sintered plate in a particularly simple manner with the housing. For this purpose, the sintered plate can be welded to the edges of the recess into which the sintered plate is inserted.

Sintered plates are usually used as a filter element and are air and thus sound permeable. Upon actuation of a valve in the receiving space of the housing resulting sound can pass without interference from the interior of the receiving space to the exterior of the housing, whereby the already mentioned acoustic short circuit is provided. Through the connection between the housing interior and the environment, a pressure equalization can take place, whereby the desired reduction of the sound radiation is achieved. The air permeability of the sintered plate can be controlled by its thickness.

In a first embodiment, one of the housing main walls can be provided with a sintered plate. In an alternative, second embodiment, the second, opposite housing main wall can also be provided with a sintered plate. In this second embodiment, the sintered plates may be formed equal or different in size. In order to achieve the best possible air permeability, it may be expedient to make the respective sintered plate as large as possible in relation to the surface of the housing main wall. "As large as possible" means that the sintered plate occupies an area between 20% and 80%.

In another embodiment, it is likewise conceivable that a plurality of sintered plates are provided in respective recesses per housing main wall. As a result, if necessary, the rigidity of the housing can be improved.

An advantage of using sintered plates is that the receiving space of the housing is splash-proof and dust-proof. This provides good protection against environmental influences. In addition, protection against intervention is also given.

In another alternative or additional embodiment, the housing is provided with one or more grooves. Characterized a coupling of a bending vibration in the housing due to the actuation of the valve assembly is made difficult by the material weakening.

In this case, juxtaposed grooves may be arranged alternately on a front side and a rear side of the at least one housing main wall. As a result, the coupling is prevented in the flat part of the housing main wall, since the bending takes place in the grooves. The groove or grooves can be incorporated circumferentially in the housing main walls and in this connecting on opposite sides housing end walls. As a result, a particularly effective sound decoupling of the housing is possible.

The groove or grooves may expediently be arranged adjacent to the connection element in the at least one of the housing main walls. The closer the groove or grooves are provided adjacent to the connecting element in the at least one of the housing main walls, in particular in a circumferential shape, the more effectively the transmission of the sound waves from the valve unit to the housing can be suppressed.

This configuration is, since the housing has no breakthroughs, well protected against environmental influences, such as water spray or dust. It can be used the previously known production process, only injection molds must be modified.

The various variants of the modification of the housing described above may be provided alone or in any combination.

The various embodiments are based on the finding that the sound from the valve unit can be transmitted via the rigid connecting element to the housing of the pneumatic control unit. The coupling of the sound waves emitted by the valve unit takes place as a bending vibration on the housing main walls, which are radiated well into the audible range without further measures and lead to the unwanted noise. By forming at least one of the housing main walls as a Helmholtz resonator and / or providing a material weakening, the bending vibrations can be greatly reduced. This results in the result of the desired reduced sound radiation.

• 1 eine schematische Querschnittsansicht eines erfindungsgemäßen Pneumatik-Steuergeräts gemäß einer ersten Ausgestaltungsvariante;
• 2 eine schematische Querschnittsansicht eines erfindungsgemäßen Pneumatik-Steuergeräts gemäß einer zweiten Ausgestaltungsvariante; und
• 3 eine schematische Querschnittsansicht eines erfindungsgemäßen Pneumatik-Steuergeräts gemäß einer dritten Ausgestaltungsvariante.

The invention will be explained in more detail below with reference to exemplary embodiments in the drawing. Show it:

• 1 a schematic cross-sectional view of a pneumatic control device according to the invention according to a first embodiment variant;
• 2 a schematic cross-sectional view of a pneumatic control device according to the invention according to a second embodiment variant; and
• 3 a schematic cross-sectional view of a pneumatic control device according to the invention according to a third embodiment variant.

The 1 to 3 each show in a cross-sectional view of an inventive pneumatic control unit. A housing of the pneumatic control unit is denoted by the reference numeral 10 characterized. The plastic housing 10 comprises two opposite housing main walls 11 . 12 and the housing main walls 11 . 12 connecting housing end walls 13 . 14 on, wherein the lying parallel to the plane of the housing end walls are each not visible. The housing main walls 11 . 12 and the housing end walls 13 . 14 (Including the non-visible housing end walls, which extend parallel to the plane of the drawing) together define a receiving space 30 , In the receiving space is a valve unit 20 arranged. The valve unit 20 consists essentially of a carrier 21 and one or more on the carrier 21 arranged valves 22 , The valve or valves 22 are with a connection element 15 connected. The connection element 15 protrudes through a recess of the housing headband 14 through and allows a pneumatic and electrical connection of the valve or valves 22 , The connection element 15 is mechanically stiff with the housing end wall 14 and the housing main walls 11 . 12 connected. The connection element 15 can essentially completely over the surface of the housing end wall 14 extend.

As from the cross-sectional representations of 1 to 3 clearly visible, the valve unit extends 20 essentially parallel to the housing main walls 11 . 12 , This is the recording room 30 by the position of the valve unit 20 divided into essentially two cavities. The first cavity is between the housing main wall 11 and the valve unit 20 educated. The second cavity is between the valve unit 20 and the housing main wall 12 educated. It should be noted that this arrangement is merely exemplary and the receiving space 30 could also have only a single cavity, for example when the valve unit 20 to the housing main wall 12 adjacent and connected to this, for example by gluing, a large area.

When operating the valve or valves 22 the valve unit 20 noises occur in the form of structure-borne noise. The noises arise on the one hand by the switching of the valve or valves 22 itself as well as through the air flowing through the valve or valves and a pressure surge when switching respective valves. Due to the rigid connection of the valve or valves 22 over the connection element 15 to the housing 10 these noises are transmitted as structure-borne noise to the housing 10 , The in the 1 to 3 described, different variants contribute to a reduction of noise emission.

According to the in 1 shown variant, the opposite housing main walls 11 . 12 as well as the housing end wall 13 a number of holes 16 (generally recesses). Although such a perforated housing still has resonances in an audible range for people. By operating the valve or valves 22 bending vibrations occur in the housing 10 , which are emitted to the environment. Because inside the case 10 , ie the cavity formed, the air through the presence of holes 16 oscillates out of phase, this airborne sound is directed to the outside. As a result, it compensates for much of the outside of the housing 10 radiated air wave. Thus, the cavity forms (this is the receiving space minus the through the valve unit 20 occupied volume) with the openings / holes 16 a Helmholtz resonator.

The holes 16 are dimensioned such that in the unwanted frequency range no amplified radiation, but a substantial compensation results. This can be the size and / or number and / or shape of the holes 16 be varied in a suitable manner. The frequency which is to be damped by the Helmholtz resonator depends on the total hole area. There may be either many small holes or comparatively less large holes in the housing main walls 11 and or 12 and / or the housing end wall 13 and / or the other housing end walls are provided.

Basically, it is sufficient if one or more holes 16 only in one of the housing main walls 11 or 12 are provided, depending on the location and nature of the valve unit 20 in the recording room 30 is. The shape of the holes 16 is basically not essential to the operating principle. For reasons of ease of manufacture, circular holes are preferably formed.

2 shows an alternative embodiment variant, in which only by way of example in the opposite housing main walls 11 . 12 in respective recesses 17 a sintered plate 18 is used. Preferably, the sintered plate 18 made of the same plastic material as the housing 10 , eg PP or PE. This allows a respective sintered plate 18 be connected to the edges of the recess 17, for example by welding, cohesively. This results in a high mechanical Strength with good protection against environmental influences, such as dust and / or moisture.

The sintered plates 18 are air and sound permeable. These can be purchased in different strengths as semi-finished products. Among other things, the strength of the sintered plate, the degree of air permeability can be controlled. Such sintered plates can be obtained, for example, from Porex.

In an alternative embodiment variant, which is not illustrated figuratively, only a single one of the housing main walls 11 or 12 could also be provided with such a sintered plate 18 be provided. Likewise, it is possible in a further embodiment variant that per housing main wall 11 and or 12 Also, more than one sintered plate is provided. As a result, if necessary, the rigidity of the housing 10 be influenced in the desired manner.

Sintered plates are permeable to air due to their porosity and therefore well suited to the desired pressure equalization between the interior of the housing 10 and the exterior. This also forms the in 2 variant shown a Helmholtz resonator.

At the in 3 shown embodiment variant, the housing is on the housing main walls 11 . 12 and the not apparent Gehäusestirnwandungen, which are parallel to the plane, with circumferential grooves 19a . 19i educated. The parallel grooves 19a . 19i are preferably close to the housing end wall 14 introduced to the initiation of a bending wave in the main surface portion of the housing main walls 11 . 12 to prevent. From the connection element 15 and the housing end wall 14 outgoing bending waves are from the material weakenings in the form of grooves 19a . 19i recorded so that they no longer in the direction of the main surface portion of the housing main walls 11 . 12 and can spread the housing end walls, not shown.

The cross-sectional shape of the grooves can, as in 3 shown to be rectangular. In principle, the cross-sectional shape of the grooves can be arbitrary. In essence, the weakening of the material is important here.

At the in 3 shown embodiment, only three juxtaposed grooves 19a . 19i intended. The number of grooves may be larger or smaller. Basically, a single groove is also already sufficient to reduce the sound radiation.

A particularly effective sound radiation results when juxtaposed grooves alternately on a front side 11a respectively. 12a and a back 11i respectively. 12i the respective housing main walls 11 respectively. 12 (And the corresponding, not shown housing end walls, which extend parallel to the plane) are arranged. This shows the case 10 in the region of the alternately arranged grooves on a low rigidity, whereby the bending waves no longer in the direction of the main surface of the housing main walls 11 . 12 of the housing 10 can spread.

Since the case at the in 3 closed embodiment shown, there is a good protection against external environmental influences.

All three variants have a significantly reduced noise emission in common. At variants according to 1 and 3 The manufacturing process can continue as before. Only injection molding tools or reworking for the introduction of the holes 16 or grooves 19a . 19i are required.

The in the three embodiments according to the 1 to 3 Variants shown can be combined with each other. Thus, for example, a number of holes may be provided in a housing main wall and a sintered plate may be provided in the opposite housing main wall. In addition, the introduction of one or more material weakenings, for example in the form of grooves, with this or the in 1 and 2 combined variants are combined.

LIST OF REFERENCE NUMBERS

10

casing

11, 12

Gehäusehauptwandung

11a, 12a

outside

11i, 12i

inside

13, 14

Housing end wall

15

connecting element

16

hole

18

sintered plate

19a, 19i

groove

20

valve unit

21

carrier

22

Valve

30

accommodation space

Claims (12)

Housing for a pneumatic control unit (1), comprising: - housing end walls (13, 14) connecting two housing main walls (11, 12) and the housing main walls (11, 12), which together form a receiving space (30) for receiving a valve unit ( 20) limit; - A connection element (15) in a housing end wall (14) for pneumatic and electrical connection of the valve unit (20), wherein the two opposite housing main walls (11, 12) are mechanically connected to the connection element (15); characterized in that - at least one of the housing main walls (11, 12) is designed as Helmholtz resonator and / or at least partially provided with a material weakening. Housing after Claim 1 , characterized in that the at least one of the housing main walls (11, 12) with one or more holes (16) is provided. Housing after Claim 1 or 2 , characterized in that at least one of the housing end walls (13, 14) is provided with one or more holes (16). Housing after Claim 2 or 3 , characterized in that the hole area as a function of the remaining space in the receiving space (30) when the valve unit (20) is arranged in the receiving space (30) is set such that the frequency of the Helmholtz resonator greater than 1 kHz, in particular greater than 3 kHz. Housing according to one of the preceding claims, characterized in that the at least one of the housing main walls (11, 12) with an air- and sound-permeable sintered plate (18) is provided, which in a recess (17) of the housing main wall (11, 12) used is. Housing after Claim 5 , characterized in that the sintered plate (18) with the edges of the recess (17) is welded. Housing after Claim 5 or 6 , characterized in that the sintered plate (18) consists of a plastic, in particular the material of the housing (10). Housing according to one of the preceding claims, characterized in that the housing (10) is provided with one or more grooves (19a, 19i). Housing after Claim 8 , characterized in that juxtaposed grooves (19a, 19i) alternately on an outer side (11a, 12a) and an inner side (11a, 12i) of the at least one of the housing main walls (11, 12) is arranged. Housing after Claim 8 or 9 , characterized in that the groove or grooves (19a, 19i) circumferentially in the housing main walls (11, 12) and these are connected on opposite sides connecting housing end walls. Housing after one of Claims 8 to 10 , characterized in that the groove or grooves (19a, 19i) adjacent to the connection element in the at least one of the housing main walls (11, 12) is arranged. Pneumatic control unit with a housing (10) and a valve unit (20), characterized in that the housing (10) is designed according to one of the preceding claims.

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