DE10207598A1 - Pressurizing medium reservoir, especially for use in motor vehicle ABS or ESP control circuits, has two chambers for gas and fluid and a separate measurement chamber for determining valve activation element position - Google Patents

Abstract

The pressurizing medium reservoir (1) has a housing in whose inner space there are two chambers (6, 7) that are separated by a media separation element so that the first chamber can be filled with gas and the second chamber with liquid. A valve (10) is provided whose shutting body (11) can be activated by the media separation element, so that filling of the second chamber with liquid can occur and so that the second chamber cannot be completely emptied. A measurement device (15), in a separate area (14), senses the position of the media separation element, The invention also relates to a corresponding method for operating a pressurizing medium reservoir.

Description

The invention relates to a pressure medium accumulator with a Ge housing, the interior of which is divided into two by a media separating element Chambers is divided, the first chamber with a medi um, especially with a gas under pressure and the second chamber is filled with a liquid and wherein a valve is provided, the closing body by the Me serving separating element is actuated and the filling of the two chamber with liquid and complete Emptying of the second chamber prevented.

In a pressure medium circuit known from WO 0031420 A1 The media separating element is a metal one Bellows formed and separated the first medium-filled Chamber from the second medium-filled chamber. To the one in the Pressure medium accumulator (second chamber) existing pressure medium determine inventory, and if necessary, a pressure generator to fill up this chamber of the pressure medium accumulator is in a pressure-connected to the first chamber Housing niche provided a measuring device, which the determ the removed pressure medium volume by sensing allowed a relative displacement of the bellows. About The data obtained is averaged in the opposite direction Exercise atmosphere leading cable duct provided, wel with a central electronic control unit for the Data processing is connected. Sealing the cables implementation is of particular importance because this is next to a high pressure alternating stress also in motor driving  testify to the usual changes in temperature in a loading range from about -40 ° C to 120 ° C. Therefore, for the Sealing towards the ambient atmosphere is a local Glazing provided. The effort to make the Implementation is considered disadvantageous.

It is an object of the present invention, the effort reduce for the manufacture of the pressure fluid reservoir. Furthermore, the position detection of the media separation element Optimized for improved pressure control become. Another task concerns the provision of egg ners improved method for operating a print with telspeichers.

The task is essentially based on the characteristics of the characteristic Sign of claim 1 solved. The fluid pressure cher is with one, apart from the chambers and the media separated room with a measuring device for sensing the positi provided on the media separating element. Because the line is exposed to ambient pressure, the High pressure cycling. Because the local glazing is eliminated, the effort for the production of the implementation tion reduced. Because the measuring device is hermetic to a certain extent is separated from the chambers, a liquid filling could the first chamber can be made with a fluid, to achieve an improved storage characteristic. This he allows a reduced size with the same volume budget of the pressure medium storage (reduction of gas-related dead volume mens).

The separation of the room is preferably carried out with atmosphere  pressure from the first chamber based on a pressure on the Ge housing sealed wall.

It will take up a small amount of space in the pressure medium reservoir is sufficient if the space is cylindrical and in the axial direction tion engages in the first chamber. The room is also koa xial to a pressure medium storage axis is provided.

A measuring body is assigned to the media separating element and translational displacement in relation to the measuring means intended. The measuring body encircles the space in a ring or tubular and is guided on the wall. This will radial centering, which ensures trouble-free, enables precise position determination.

An intelligent accumulator for easy networking connection with other electronic components is possible light if the measuring means a sensor and at least one integrated, in other words locally provided, electro African storage and / or control unit for device data having.

The measuring means is based on a magnetic field change which is sensed, and it can follow in many ways (moving coil, Hall sensor, reed switch or the like). If the measuring body has a variable wall thickness over its length, a linear position signal of the media separating element can be generated. For example, the measuring body is conical and consists of a ferromagnetic material ( Fig. 1 and Fig. 2), or an air gap change between the wall and the ferromagnetic measuring body is used ( Fig. 3).

The media separating element is preferably made thin by a walled and consequently light metallic bellows which forms a permanent and fatigue-free mediense parrying enabled.

An inductive displacement sensor with a coil is used as the measuring means provided, and in the storage and / or control unit the inductance of the coil is determined on site. In wide The modification can be in the storage and / or control with the help of stored characteristic curves, device data, and from the inductance of the coil the level of the pressure medium storage can be determined. It is also conceivable the direct current wi in the storage and / or control unit the state of the coil. In advanced training at the Erfin dung can in the storage and / or control unit by means of stored characteristic curves from the (direct current) resistance the coil determines the temperature in the pressure medium accumulator become.

An intelligent pressure medium reservoir has an inte grierte storage and / or control unit, in the characteristic values of the memory are stored, the characteristic values using ei ner central control unit can be read out automatically. This simplifies assembly and electronic networking a pressure medium storage for use with an electro-hydraulic motor vehicle brake system because automated component recognition takes place. With others Words can be a separate process step to separate There is no need to read in the characteristic values.  

The invention is described in the following description of three embodiments with reference to the enclosed ing drawing explained in more detail. The drawing shows:

Fig. 1 shows two separated clarified by a memory center axis embodiments; on average,

Fig. 2 details of the measuring means enlarged and in section along the line II-II in Fig. 1, and

Fig. 3 shows a third embodiment of the pressure medium reservoir in axial section.

A pressure medium reservoir 1 comprises a housing 2 made of an upper part 3 and a lower part 4 fastened to it in a pressure-tight manner. An interior of the housing 2 is divided into two chambers 6 , 7 by means of media separating element 5 . The Medientrennele element 5 is preferably formed by a thin-walled, metallic bellows which is pressure-tight on the one hand with egg nem housing part 3 , 4 and on the other hand closed by a plate 8 which forms a reference plane b for a measuring body explained in more detail below. The interior of the bellows forms the first chamber 6 , which can be filled with a gas, which is generally under high pressure, via a filling connection (not shown ) provided in the upper part 3 . In order to avoid damage to the bellows when filling, a filler not shown in FIG. 1 can be provided. In the lower part 4 a hy draulic connection 9 is formed, in which a valve 10 is arranged, the closing body 11 protrudes into the second chamber 7 , so that it can be actuated by the plate 8 . The valve 10 is preferably designed such that on the one hand it enables the second chamber 7 to be filled with a pressurized liquid pressure medium, for example a brake fluid, and on the other hand prevents the second chamber 7 from being completely emptied. In addition, a compression spring 12 can be found in the first chamber 6 , which is clamped between the upper part 3 and the plate 8 and thus elastically prestresses the bellows in the direction of the valve 10 . This ensures that the hydraulic pressure prevailing in the second chamber 7 is always higher than the gas pressure prevailing in the first chamber 6 . In order to finally center the bellows in the housing 1 , a ring 13 can be provided which engages around the plate 8 and, in the assembled state, rests on the wall of the housing 2 in a relatively movable manner.

As shown in FIG. 1, is separated in one of the media and from the first chamber 6 to atmosphere, a substantially jerk-rend level lying chamber 14 a measuring means 15 for Sen the position of the media separating element 5 tion provided. To separate the room 14 , a wall 16 is provided which, together with the upper part 3 and the media element 5, delimits the chamber 3 , and consists of an antimagnetic material such as plastic, austenitic steel or aluminum. The wall 16 can be designed as a sleeve open on one side in the direction of the surroundings, which is connected to the upper part 3 in a pressure-resistant manner and is subsequently closed with a lid. The space 14 has a cylindrical-tubular cross section, which engages in the axial direction - coaxially to a central storage axis 17 , as well as centrally - into the interior of the first chamber 6 . A together with the plate 8 of the Medientrennelemen tes 5 translationally movable and on the wall 16 slidably guided measuring body 19 encompasses the space 14 in wesent union ring. A displacement of the measuring body 19, which is pressed elastically by means of compression spring 12 to bear against plate 8, is representative of a displacement of the media element 5 relative to the fixed measuring means 15 .

Fig. 1 can be seen that the left of the Speicherermit telachse 17 illustrated embodiment has a measuring body 19 with wall length d variable over its length, so that a linear measurement signal can be generated by influencing a magnetic field (magnet 32 ). For this purpose, the measuring body 19 is conical on the outside and consists (at least partially) of a ferromagnetic, magnetic field-influencing material. Consequently, each Ver displacement of the measuring body 19 relative to the measuring means 15 causes a change in the sense of a weakening or amplification of the detected magnetic field (sensor 20 ), which is converted into a corre sponding electrical signal. Inside, the measuring body 19 has a recess 18 for receiving the delimited space 14 . When the chamber 7 is filled, the space 14 is taken up essentially completely by the recess 18 .

A sensor 20 is fixed in the room 14 and is preferably based on a magnetic principle for monitoring a change in the magnetic field. It can be, for example, a coil / plunger for inductive displacement measurement, a Hall sensor or a reed switch. In addition to the sensor 20 , a magnet 32 and a yoke 36 for the directional emission of a magnetic field of (shunt) as well as a storage and / or control unit 33 with an electronic circuit can be provided in the space 14 , the function of which below and on the basis Fig. 2 is described in more detail.

The embodiment shown in FIG. 1, to the right of the storage center axis 17 , has an essentially tubular measuring body 19 a, which is arranged so as to be slidably movable with at least two, preferably three guide sections 34 , which extend parallel to the wall 16 . In addition, one (or more) conically cranked section 35 is provided for targeted magnetic field influencing, which has an air gap in the direction of wall 16 , the width (s) of which is rich in the measuring means 15 due to displacement of the measuring body 19 a. The section 35 has a uniform thickness, so that the magnetic field is influenced by changing the air gap.

Fig. 2 shows the measuring means 15 to associated components within the space 14. A yoke, for example made of soft iron, receives a magnet 32 in a recess. A sensor 20 is located diametrically opposite the magnet 32 , in particular a Hall sensor sensitive to a magnetic field for detecting a change in the magnetic field. The sensor 20 is connected to a local storage and / or control unit 33 (Asic), and this via an electrical line, which is only exposed to the ambient pressure, to an external evaluation unit (ECU), not shown. A wall 16 made of antimagnetic material is used for pressure-resistant partitioning relative to the chamber 6 . The arrangement of the Messmit tel 15 associated and provided within the room 14 components such as control unit 33 and electrical rule's can be secured with a cavity-filling, antimagnetic potting compound.

Radially outside of the wall 16 (on the left side of FIG. 2) the butted measuring body guided on the wall is illustrated by 19 with the local thickness d. On the right-hand side of FIG. 2, the measuring body 19 a with the air gap present between wall 16 and section 35 represents Darge.

The embodiments of FIGS . 1 and 2 have in common that the measuring means 15 is arranged in an independent unit 26 , which is inte grated in the housing 2 of the memory 1 . The attachment is gastight, preferably by means of (laser) welding processes. This makes it possible light to manufacture the measuring means 15 as an independent assembly. The space 14 is formed centrically to the Speichermittittelach 17 and is closed by a cover 27 which is provided with a plug connection 28 .

Fig. 3 is a substantially in accordance with Fig. 1 embodiment to be inferred, matching features are provided with matching reference numerals. In a one-sided open and filled with an anti-magnetic potting material made of antimagnetic material, which forms the wall 16 , is as in Fig. 1, a measuring means 15 and a control unit 33 , which are connected to each other with electrical conductors and to an external, not shown Unit are connected. The adjustment of the measuring arrangement relative to the Druckmittelspei cher 1 can basically be carried out in two different ways. If the sleeve is fixed to the housing 2 , a sensor 20 can be sensitive to the housing 2 in the direction of a casing, potting compound or the like the arrow A moved and after positioning by Ver caul 37 of the sleeve relative to the housing 2 can be set. On the other hand, it is possible to move a unit of sensor arrangement and sleeve relative to the housing 2 and, after positioning - for example by welding (in particular laser beam welding) in a region 38 to be loading. A measuring body 19 b engages around the sleeve in a tubular manner and is guided on it with end sliding surfaces. Wall 16 or sleeve and measuring body 19 , 19 a, 19 b be preferably made of materials with an identical or comparable coefficient of linear expansion in order to prevent jamming when the temperature changes. The coefficient of expansion of the wall 16 or sleeve can in principle also be less than the coefficient of expansion of the measuring body 19 , 19 a, 19 b. A magnet 30 is set back relative to the equal surfaces and emits a magnetic field, the influence of which (by displacement of the measuring body 19 b) is detected by a coil 20 , sensor or the like. If a coil is used, its DC resistance can be used to draw conclusions about the temperature in the Druckmit telspeicher 1 , which in turn has an influence on the volume of medium in stock.

As can be seen on the right-hand side of FIG. 3, a spring-elastic element 12 provided between the housing 2 and the measuring body 19 b is used for pressing the measuring body 19 b onto plate 8 , which is connected to the bellows. This provides a defined contact of the measuring body 19 b on the plate 8 . The left side of Fig. 3 is a federelasti cal element 12 b can be seen, which is fixed to the plate 8 , and acts with elastic biasing force on the measuring body 19 b. This facilitates the assembly of the pressure medium accumulator because it is not necessary to hold the upper part 3 against the force of the spring 12 in a position in which the upper part 3 and the lower part 4 are connected to one another.

The local, storage and / or control unit 33 (ASIC = Application-Specific-Integrated Circuit) integrated in the room 14 enables a large number of functionalities. On the one hand, this enables the preparation of a measurement signal and, in addition, a plausibility check for error monitoring. This ensures that only plausible data records are transmitted to neighboring units, for example an ABS / ESP control unit. The plausibility check can be carried out, for example, by permanent comparison of two redundantly obtained signals, which are processed in mutually independent storage and / or control units. It is also possible to use an inverse signal of the main signal obtained separately for the plausibility check.

Another task of the storage and / or control unit 33 relates to performing a calibration of the measuring means 15 and, if appropriate, storing calibration values such as the top and bottom dead center of the measurement separating element 5 . This allows tolerance influence to be eliminated, a more precise display to be achieved and, for example, a brake system to be designed to be fault-free. If necessary, calibration values can be automatically passed on to an ABS / ESP control unit. The local data storage consequently permits communication - for example via a CAN bus connection - between the local control and / or storage unit 33 and a central control unit (ABS / ESP control unit) arranged elsewhere in a motor vehicle, with locally stored data Certain times, for example, clocked or interchangeable at certain operating conditions (for example, when starting a vehicle). According to another embodiment, prior to a communicative data exchange between the control units, a possible mutual identification takes place by exchanging an identification code, which is checked for correctness (match). The measures described above allow a so-called plug-and-play possibility between the pressure medium storage and the central control unit, because identification and communication take place to a certain extent themselves, so that a complex, separate programming process or data reading process in the central control unit is omitted. If - for example as a result of a defect - a pressure medium store 1 with a local control and / or storage unit 33 is replaced with a new device, the new part is automatically recognized and the necessary data, calibration values and / or identifications are carried out as part of an automated identification routine onscodes exchanged. This is particularly advantageous if the pressure medium accumulator 1 in a motor vehicle is arranged spatially from other units (for example a hydraulic control unit). Because it is impossible in any case that a central control unit is supplied with false, in particular interchanged calibration values, because an automated identification takes place.

Claims (27)

1. pressure medium accumulator ( 1 ) with a housing ( 2 ), the interior of which is divided by a media separating element ( 5 ) into two chambers ( 6 , 7 ), the first chamber ( 6 ) with a medium, in particular with an excess pressure standing gas and the second chamber ( 7 ) is filled with a liquid and a valve ( 10 ) is seen before, the closing body ( 11 ) of which can be actuated by the measuring element ( 5 ) and which fills the second chamber ( 7 ) with liquid and prevents complete emptying of the second chamber ( 7 ), characterized in that the housing ( 2 ) has a space ( 14 ) separated from the chambers ( 6 , 7 ) and the media with a measuring means ( 15 ) for sensing the Has position of the media separating element ( 5 ). 2. Pressure fluid accumulator according to claim 1, characterized in that the space ( 14 ) with a wall ( 16 ) from the first chamber ( 6 ) is separated. 3. Pressure fluid accumulator according to claim 2, characterized in that the wall ( 16 ) consists of antimagnetic material such as aluminum, austenitic steel or plastic. 4. Pressure fluid accumulator according to claim 1 or 2, characterized in that the space ( 14 ) engages in the axial direction in the first chamber ( 6 ). 5. Pressure fluid accumulator according to claim 1, 2 or 4, characterized in that the space ( 14 ) is provided centrally in the Ge housing ( 2 ). 6. Pressure fluid accumulator according to one or more of the preceding claims, characterized in that the measuring means ( 15 ) has a sensor ( 20 ) and at least one integrated electronic storage and / or control unit ( 33 ) for device data. 7. pressure medium accumulator according to one or more of the preceding claims, characterized in that the media separating element ( 5 ) is assigned a measuring body ( 19 , 19 a, 19 b) for translational displacement relative to the measuring means ( 15 ), and that the measuring body ( 19 , 19 a, 19 b) encompasses the room ( 14 ). 8. Pressure fluid accumulator according to one or more of the preceding claims, characterized in that the measuring body ( 19 , 19 a, 19 b) in the radial direction on the wall ( 16 ) of the space ( 14 ) is centered, and that a resilient element ( 12 , 12 a) is provided which weles the measuring body ( 19 , 19 a, 19 b) elastically to abut the media separating element ( 5 ). 9. Pressure fluid accumulator according to one of claims 1 to 8, characterized in that the measuring body ( 19 ) has a variable wall thickness (d) over its length. 10. Pressure fluid accumulator according to one of claims 1 to 8, characterized in that an air gap is provided between the wall ( 16 ) and measuring body ( 19 a), and that the width of the air gap (s) in the region of the measuring means ( 15 ) by displacement of the measuring body ( 19 a) is changeable. 11. Pressure fluid accumulator according to claim 10, characterized in that the rele vante for influencing the magnetic field section ( 35 ) of the measuring body ( 19 a) has a uniform wall thickness, which is flared, so that a substantially emptied chamber ( 7 ) There is an air gap of great width (s) between wall ( 16 ) and section ( 35 ), and that when the chamber ( 7 ) is essentially full, an air gap of small width (s) is provided, or vice versa. 12. Pressure fluid accumulator according to one of claims 1-9, characterized in that the measuring body ( 19 ) is ko African outside, and in that a recess for receiving a structural unit ( 26 ) with the measuring means ( 15 ) is provided. 13. Pressure fluid accumulator according to one of claims 1-9 or 12, characterized in that the measuring body ( 19 , 19 a) consists of ferromagnetic material. 14. Pressure fluid accumulator according to one of claims 1-8, 10 or 11, characterized in that the measuring body ( 19 b) has a magnet ( 30 ). 15. Pressure fluid accumulator according to one or more of the preceding claims, characterized in that the space ( 14 ) is filled with an antimagnetic material, in particular with plastic. 16. Pressure fluid accumulator according to one or more of the preceding claims, characterized in that the space ( 14 ) is arranged centrally in the first chamber ( 6 ). 17. Pressure medium accumulator according to one or more of the preceding claims, characterized in that the media separating element ( 5 ) is formed by a metallic bellows. 18. Pressure fluid accumulator according to one or more of the preceding claims, characterized in that the measuring means ( 15 ) has a Hall sensor, which egg ne, initiated due to displacement of the measuring body ( 19 , 19 a, 19 b), sensed magnetic field change. 19. A method of operating a pressure medium store, in particular according to claim 1, characterized in that certain memory-related data, such as characteristic values are stored in a local storage and / or control unit ( 33 ), and that the data can be read out by means of a central control unit , 20. A method of operating a pressure medium accumulator according to claim 19, characterized in that the inductance of a coil is determined in the storage and / or control unit ( 33 ). 21. A method of operating a pressure medium accumulator according to one of claims 19 or 20, characterized in that in the storage and / or control unit ( 33 ) with the aid of stored characteristics from the inductivity of the coil, the fill level of the pressure medium accumulator ( 1 ) is determined , 22. A method for operating a pressure medium store according to one of claims 19 to 21, characterized in that the electrical resistance of the coil is determined in the storage and / or control unit ( 33 ). 23. A method of operating a pressure medium accumulator according to one of claims 19 to 22, characterized in that in the storage and / or control unit ( 33 ) by means of stored characteristics from the DC resistance of the coil, the temperature in the pressure medium accumulator ( 1 ) is determined , 24. The method for operating a pressure medium accumulator according to one of claims 19 to 23, characterized in that that redundant measurement signal processing is carried out becomes. 25. Method for operating a pressure medium accumulator according to one of claims 19 to 24, characterized in that that a plausibility check of the measurement signal is carried out men will. 26. A method of operating a pressure medium store according to one of claims 19 to 25, characterized in that calibration values and / or an identification code are stored in the memory and / or control unit ( 33 ). 27. A method of operating a pressure medium store according to one of claims 19 to 26, characterized in that a communication link between the central control unit and the pressure medium store ( 1 ) is yorgese hen, and that an automated identification of the control units by means of permanent, or clocked or to certain operating states data is exchanged.