DE102018222523A1 - Brake system damper device - Google Patents

Abstract

The invention relates to a brake system damper device (10) having a space (12) in which a hydraulic pressure (14) is to be applied, a plurality of elastic elements (20) being provided in the space.

Description

State of the art

The invention relates to a brake system damper device with a space in which a hydraulic pressure is to be applied, and to a method and a device for producing elements of such a brake system damper device.

Vehicle brake systems, especially hydraulic brake systems, serve to slow down the driving speed of vehicles, such as cars and trucks. Various dynamic effects occur in the operation of such brake systems, including pressure fluctuations, which can lead to oscillations and thus to undesirable noises and vibrations. In order to minimize such vibrations, brake system damper devices, also referred to below as dampers, are used. These dampers encompass a space in which hydraulic pressure is to be applied. The pressure comes from hydraulic force that is transmitted in a line via the associated brake fluid.

Damper with a membrane, so-called membrane damper, are known. The membrane is often made from an elastomer, that is, from a dimensionally stable but elastically deformable plastic. Membrane dampers exist in different forms. For example, disk-shaped, flat or cup-like membranes are used. Pot-like membranes have the advantage over membranes of different shapes that the space required to dampen a vibration can be provided in an elongated space with a certain diameter.

The invention has for its object to provide a simple and inexpensive device for damping vibrations in a brake system.

Disclosure of the invention

According to the invention, a brake system damper device is provided with a space in which a hydraulic pressure is to be applied and which is characterized in that a plurality of elastic elements is provided in the space.

An element is elastic when it changes its shape under the influence of force and returns largely or completely to its original shape when the force is removed. According to the invention, a large number of such elastic elements are arranged as separate parts close to one another in a room.

By means of this large number of elastic elements, part of an overall damping effect is taken over from each individual element. A total failure is unlikely due to the large number of elements. If individual elements fail, the damping effect is largely retained by the other elements.

With this amount of individual damping elements, the overall damping effect achieved can be made variable by arranging them in rooms of different sizes, making them from different materials, providing them in different sizes and / or providing them in different numbers. Such targeted scaling allows the brake system damper device to be easily adapted to a wide variety of customer and functional requirements. As a result, a wide variety of requirements with regard to damping audible and perceptible vibrations, so-called noise, vibration and harshness (NVH), can be advantageously met.

The invention is based on the knowledge that when a diaphragm damper is used, regardless of its shape, a total failure of the damper cannot be completely ruled out. If the membrane is destroyed or loses its function, the damping effect in the brake system can no longer be maintained. In addition, the membranes are limited in their geometric design. The combination of different materials in one membrane can only be realized at high costs.

In order to achieve a sufficient damping effect of a diaphragm damper, it is necessary to provide sufficiently large spaces on both sides of the diaphragm so that they absorb and release correspondingly large amounts of brake fluid. Components used in modern brake systems, such as pumps, valves and lines, are mainly packed tightly to save weight and costs. As a result, there is only a limited space for the damper.

With the brake system damper device according to the invention, these disadvantages of known techniques are also advantageously overcome.

In an advantageous embodiment of the solution according to the invention, the elastic elements are viscoelastic elements. Viscoelastic elements are elements that are both elastic and viscous. An element is viscous if it exhibits viscous material behavior. The viscoelastic elements thus combine elastic and viscous material behavior. They can become spontaneously reversible and, at the same time, irreversible depending on the time deform. The damping effect is completely guaranteed, only a return of an element to its original form is delayed or slower. This additionally prevents the generation of vibrations by these elements themselves.

The elastic elements are preferably lenticular and / or spherical. Such elements are particularly easy to manufacture. In addition, due to the lack of edges and corners, a dense, even packing of such elements is achieved in the associated room.

In a preferred embodiment, the elastic elements are made of different materials. As a result, materials of different hardness and / or different elongation behavior can be used in a very simple manner, which then lead accordingly to different damping behavior.

In a further preferred embodiment, the elastic elements have different sizes. With elements of different sizes, a space, preferably a given installation space, can be filled in different ways and the damping effect can be influenced accordingly. Smaller elements take advantage of remaining gaps between larger elements.

The elastic elements are preferably of such a small size that they can get into areas of the room that are difficult to access. Under certain circumstances, at least one area of the room is only accessible to small elements, since such an area is only connected to the remaining area of the room via a small opening, for example. If at least some of the elastic elements can pass through this small opening, the available space is better utilized and the damping effect of the brake system damper device is thus improved.

In a further advantageous embodiment, at least some of the elastic elements are made from a foamed plastic. The elements foamed in this way can be varied not only in terms of their size and shape, but also in terms of pore size, shape and number of pores. Accordingly, there is a high degree of variability.

According to a further embodiment, the space is delimited by a housing, the housing preferably being a metal housing. Housing made of ceramic or plastic are also advantageous. The housing is preferably a metal body with a cavity, which represents the available space. The housing provides the brake system damper device with the necessary overall stability.

In a further preferred embodiment, the space is delimited by means of a membrane. The use of a membrane as a delimitation prevents brake fluid from entering, in particular also from diffusing, into the space filled with elastic elements. Diffusion is an equalization of concentration differences in liquids and gases. The life of the brake system damper device is significantly increased by the membrane as a kind of protective layer for an inside of a housing.

In an embodiment based on this, the membrane is pot-shaped. The pot-shaped membrane has the advantage that a required volume for damping a vibration can be provided in an elongated space with a small diameter.

The object on which the invention is based is further achieved with a method for producing a large number of elastic elements for such a brake system damper device according to the invention, comprising the following steps: providing a rubber strand by means of an extruder and a melting valve, dividing the rubber strand into a plurality of elastic elements by means of a cutting tool in a medium and separating the plurality of elastic elements from the medium, the medium being tempered to a higher temperature than the melting valve.

The invention is based on the finding that particularly small spherical elastomer balls are desirable as a large number of elements with a diameter of less than 0.5 mm. Such elements cannot be produced using known extrusion processes. According to the invention, however, an extrusion process is created in which a rubber is specifically used as the material for the elastomer balls and this material is then extruded comparatively cold. In this way, crosslinking of the rubber is prevented according to the invention. According to the invention, when cutting the rubber strand by means of a cutting tool, a medium is supplied which is heated or heated to a higher temperature than the material was during the extrusion process. The separated parts of the rubber strand, that is to say the individual elastic elements thus created, are simultaneously removed by means of the medium. A cross-linking of the rubber is specifically stimulated and guaranteed with the tempered or heated medium. The medium is therefore preferred heated above the crosslinking temperature of the respective rubber material.

In the extrusion process, the associated melting valve is particularly preferably heated to a temperature of below 120 ° C. This ensures reliable extrusion of rubber material.

The medium used according to the invention for tempering the cutting process and for removing the plurality of elastic elements is preferably formed with a salt bath. Alternatively, the medium is formed with an oil. Such media can ensure a clean separation of a multitude of smallest elements and at the same time advantageously contribute to the networking of these elements.

As an alternative to the above-mentioned tempering by means of a heated medium or also in addition to this process, a physical blowing agent is added in a further solution according to the invention in the extruder. The blowing agent causes the elements produced according to the invention to be foamed. At the same time, these elements in particular form a spherical shell, i.e. a kind of spherical skin around an inner, foamed core. The core is formed from pores, which are particularly gas-tight and at the same time elastically compressible. When exiting the melting valve used according to the invention into the associated, in particular liquid medium, a pressure loss occurs, which leads to the formation of foam cells within the emerging material. At the same time, a crosslinking reaction takes place in parallel or simultaneously, with which the material and its pore structure are frozen. In this way, crosslinked, viscoelastic elements or particles, in particular polymer balls, can advantageously be produced. This process can be carried out with short cycle times. In this way, elastic elements can be produced in large numbers and with varying particle sizes. The variation takes place by using different process parameters.

The object on which the invention is based is furthermore correspondingly achieved with a device for carrying out such a method according to the invention for producing a plurality of elastic elements for a brake system damper device, comprising: an extruder and a melting valve for providing a rubber strand, a cutting tool for dividing the rubber strand into a plurality elastic elements in a medium and a separating device for separating the plurality of elastic elements from the medium, wherein a tempering device is provided for tempering the medium to a higher temperature than the melting valve.

In addition, further embodiments are possible. The brake system damper device according to the invention is preferably installed in a system with an electronic stability program (ESP), traction control system (ASR) or anti-lock braking system (ABS). In this case, with the brake system damper device, preferably in regular operation, longitudinal vibrations caused by a pump of the brake fluid located in a suction line of the pump are avoided. As a result, the pump can deliver a large volume flow for rapid pressure build-up and release on wheel brake cylinders.

• 1 einen Längsschnitt eines ersten Ausführungsbeispiels einer erfindungsgemäßen Bremssystemdämpfervorrichtung,
• 2 einen Längsschnitt eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Bremssystemdämpfervorrichtung und
• 3 einen Längsschnitt eines dritten Ausführungsbeispiels einer erfindungsgemäßen Bremssystemdämpfervorrichtung.
• 4 eine schematische Ansicht einer erfindungsgemäßen Vorrichtung zum Ausführen eines Verfahrens zum Herstellen einer Vielzahl elastischer Elemente

Exemplary embodiments of the solution according to the invention are explained in more detail with reference to the attached schematic drawings. It shows:

• 1 2 shows a longitudinal section of a first exemplary embodiment of a brake system damper device according to the invention,
• 2nd a longitudinal section of a second embodiment of a brake system damper device according to the invention and
• 3rd a longitudinal section of a third embodiment of a brake system damper device according to the invention.
• 4th is a schematic view of an apparatus according to the invention for carrying out a method for producing a plurality of elastic elements

In 1 is a brake system damper device 10 shown. The brake system damper device 10 contains a space surrounded by a housing 12th at which a hydraulic pressure 14 is to be created, indicated by an arrow in relation to 1 bottom side 16 of the housing. On this lower side 16 there is one from the outside in the room 12th opening 18th .

In the room 12th there are a large number of lenticular, elastic elements 20 and a brake fluid 22 . These elements 20 are designed so large that they cannot pass through the opening 18th out of the room 12th can exit.

If at the room 12th the pressure 14 is applied and this pressure 14 increases through the opening 18th Brake fluid 22 in the room 12th pushed in. The individual, from brake fluid 22 surrounded, elastic elements 20 crowded or compressed. At the same time come with the pressure 14 connected vibrations. Every single elastic element 20 now has a dampening effect on these vibrations by compressing itself and only then expanding again after a delay, if the pressure 14 becomes less in the course of the vibrations. In particular, the associated amplitude of such a vibration is reduced.

In the room 12th is the number of elastic elements 20 specifically chosen in such a way that largely all audible and perceptible vibrations of an associated brake system are damped.

In 2nd is another brake system damper device 10 illustrated. This brake system damper device 10 also includes a room 12th at which a hydraulic pressure 14 is indicated by an arrow on a lower side 16 of the room 12th . On this lower side 16 there is also an opening 18th .

The space 12th according to 2nd is in a large area of space 24th and several small room areas 26 divided that based on the 2nd right side 28 of the room 12th are arranged. The small room areas 26 are about small openings 30th with the large room area 24th connected.

In such a room 12th there are also a variety of elastic elements 20 and brake fluid 22 . The elastic elements 20 are made of viscoelastic material and spherical or in the form of small balls 32 and big balls 34 designed.

The little balls 32 have a size that gives access to each of the areas 24th and 26 of the room 12th allow. The little balls 32 fit through the small openings 30th and can therefore in the small areas 26 reach. The big balls 34 do not fit through the small openings 30th and therefore always remain in the large area 24th . Both the balls 32 the balls as well 34 are so large that they cannot pass through the opening 18th out of the room 12th can exit.

With the different sized balls 32 , 34 becomes the room 12th used efficiently and a dampening effect is enhanced. The big balls fill up 34 the large room area 24th and the little balls 32 primarily the small room areas 26 as well as between the big balls 34 remaining gaps.

The balls 32 , 34 are also made of different materials in this embodiment. The little balls 32 are made of a first plastic and the big balls 34 made of a second plastic, the first plastic being a non-foamed and the second plastic being a foamed plastic.

The 3rd shows another brake system damper device 10 . This brake system damper device 10 includes a room 12th at which no hydraulic pressure 36 is indicated, indicated by a crossed arrow on a lower side 16 of the room 12th .

In the room 12th there are also a variety of elastic elements 20 and brake fluid 22 . The elastic elements 20 here are medium-sized viscoelastic spheres 38 . The space 12th is of a cup-shaped membrane 40 with an open side 42 surround.

This membrane 40 is in turn on the outside of a housing 44 surround. At one related to 3rd bottom side 46 of the housing 44 there is an opening 48 in an area where the membrane 40 with its open side 42 rests and with the housing 44 a sealed connection 50 forms.

Between the housing 44 and the membrane 40 there is a gap 52 , creating a space 54 is formed. This space 54 fills together with the room 12th a total available space 56 .

Special features of this embodiment are that the room 12th a housing 44 and a membrane 40 has, the housing 44 from a metal and the membrane 40 are made of an elastomer. The distance 52 between housing 44 and membrane 40 exists for the reason that no hydraulic pressure 36 on the room 12th is present. As soon as a hydraulic pressure to the room 12th the membrane widens 40 up to an associated inner wall 58 of the housing 44 ,

The brake fluid 22 and the elastic elements 20 then fill the available space 56 completely out.

This can vary in the range 52 advantageously be a gas that is compressible. The membrane 40 also acts as a kind of boundary layer for the brake fluid 22 . In addition, the membrane 40 Pot-shaped to achieve a maximum damping effect in the elongated and narrow, available space 56 to provide.

In 4th is a device 60 for performing a method of manufacturing a plurality of elastic members 20 shown as above. The device 60 includes an extruder 62 , on a feeder 64 a material to be extruded 66 , in the present case rubber in particular can be supplied. The material 66 gets from the feeder 64 inside the extruder 62 and is put under high pressure there. Below is the material 66 from the extruder 62 to a melting valve 68 promoted where it is melted. The melting valve 68 is operated with an operating temperature of below 120 ° C, in particular below 110 ° Celsius.

The melted material 66 arrives as a rubber strand 70 to a cutting tool 72 , on which a cutting knife rotates in front of a perforated disc or perforated plate (not shown) with between 6 and 32 holes distributed around the circumference. Using the cutting tool 72 are from the rubber strand 70 a large number of elastic elements in short intervals 20 in the form of small balls with a diameter of less than 0.8 mm, in particular less than 0.5 mm, particularly preferably less than 0.4 mm in diameter. An opening diameter for the passage of material can advantageously be used 66 varies on the perforated plate and thus the shape and size of the elements 20 to be influenced. These elements 20 get as granules from the cutting tool 72 directly to a feed and discharge device 74 of a medium 76 . The medium 76 is preferably designed with a salt bath or an oil. The Elements 20 so are in the medium 76 separated into it and washed away with it. This process is also called sub-medium granulation. In the direction of flow of the medium 76 below is a separator 80 provided on the the multitude of elements 20 from the medium 76 is separated or separated. The medium 76 itself becomes a melting valve 68 or the cutting tool 72 returned.

With such granulation, the medium 76 by means of a temperature control device 78 heated to a temperature above 120 ° C, in particular above 130 ° C and thus above the temperature of the melting valve 68 lies. Tempering is an advantageous way of crosslinking the rubber and thus of a particularly qualitatively excellent formation of particularly small viscoelastic elements 20 achieved.

In the 4th is further illustrated that on the extruder 62 alternatively to the temperature control device 78 or in addition to this a blowing agent addition device ( 82 ) for adding a physical blowing agent, not shown, into the extruder 62 can be provided. The blowing agent of this type leads to the melting valve 68 at the pressure drop there in the rubber strand 70 foaming of the material 66 .

Claims (16)

Brake system damper device (10) with a space (12) in which a hydraulic pressure (14) is to be applied, characterized in that a plurality of elastic elements (20) are provided in the space. Brake system damper device (10) after Claim 1 , characterized in that the elastic elements (20) are viscoelastic elements. Brake system damper device (10) after Claim 1 or 2nd , characterized in that the elastic elements (20) are spherical. Brake system damper device (10) according to one of the preceding claims, characterized in that the elastic elements (20) are made of different materials. Brake system damper device (10) according to one of the preceding claims, characterized in that the elastic elements (20) have different sizes. Brake system damper device (10) according to one of the preceding claims, characterized in that the elastic elements (20) are of such a small size that they also reach areas (26) of the space (12) which are difficult to access. Brake system damper device (10) according to one of the preceding claims, characterized in that at least some of the elastic elements (20) are made of a foamed plastic. Brake system damper device (10) according to one of the preceding claims, characterized in that the space (12) is delimited by a housing (44), the housing (44) preferably being a metal housing. Brake system damper device (10) according to one of the preceding claims, characterized in that the space (12) is delimited by means of a membrane (40). Brake system damper device (10) after Claim 9 , characterized in that the membrane (40) is pot-shaped. Method for producing a plurality of elastic elements (20) for a brake system damper device (10) according to one of the Claims 1 to 10 , with the steps: - providing a rubber strand (70) by means of an extruder (62) and a melting valve (68), - dividing the rubber strand (70) into a plurality of elastic elements (20) by means of a cutting tool (72) in a medium ( 76) and - separating the plurality of elastic elements (20) from the medium (76), the medium (76) being heated to a higher temperature than the melting valve (68). Procedure according to Claim 11 , characterized in that the melting valve (68) is tempered to a temperature below 120 ° C. Procedure according to Claim 11 or 12th , characterized in that the medium (76) is formed with a salt bath. Procedure according to Claim 11 or 12th , characterized in that the medium (76) is formed with an oil. Procedure according to one of the Claims 11 to 14 , characterized in that a physical blowing agent is added in the extruder (62). Device (60) for carrying out a method for producing a plurality of elastic elements (20) for a brake system damper device (10) according to one of the Claims 11 to 15 , with: - an extruder (62) and a melting valve (68) for providing a rubber strand (70), - a cutting tool (72) for dividing the rubber strand (70) into a plurality of elastic elements (20) in a medium (76) and - a separating device (80) for separating the plurality of elastic elements (20) from the medium (76), a tempering device (78) being provided for tempering the medium (76) to a higher temperature than the melting valve (68) .

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