MXPA06002913A - Ball and socket joint for a motor vehicle - Google Patents

Abstract

The invention relates to a ball and socket joint for a motor vehicle, comprising a ball pivot (3) provided with a journal (2) and an articulated ball (1). Said ball pivot is arranged in a manner such that it can be pivoted and rotated by means of the articulated ball (1) in a recess (4) provided in a housing (5) and such that it extends from said housing though a journal opening (6). The ball and socket joint also comprises a sensor which is a humidity sensor (12) which interacts with the recess (4).

Description

BOARD OF ROTULA FOR AN AUTOMOTIVE VEHICLE DESCRIPTION OF THE INVENTION The invention relates to a ball joint for a motor vehicle comprising a ball stud having a ball head, the ball stud being rotatably and pivotally disposed with its ball head in a cavity provided in a housing and extends, coming out of this, through a bolt opening; also comprising a sensor. Such a ball joint is known from DE 101 61 671 A1, whereby a magnetic field sensor is arranged in a closing element which closes an assembly opening provided in a housing. The magnetic field sensor is arranged in this in the housing and completely covered by a protective element. Ball joints for motor vehicles often have the disadvantage that moisture can penetrate into the interior of the ball joint, for example due to a defective seal, of. so that the ball surface of the ball head of the ball joint corrodes. Such corrosion can cause, however, a strong impairment of the functioning of the joint, in extreme case until its destruction. As ball joints for motor vehicles are applied also in the region of the undercarriage and represent, consequently, components with relevance for safety, it is important to detect early incipient corrosion. Based on this state of technology, the invention has the objective of creating a ball joint for a motor vehicle that allows to detect early the potential start of a corrosion. This objective is achieved inventively with a ball joint having the features according to claim 1. Preferred improvements are described in the dependent claims. The inventive ball joint for a motor vehicle comprises a bolt and a ball and socket bolt having a ball head which is rotatably and pivotally disposed with its ball head in a cavity provided in a housing and extending out of it. through a bolt opening, and a sensor that is a humidity sensor connected to the cavity. With the inventive swivel joint it is possible to detect very early the penetration of moisture inside the swivel joint, which is important, for example, in the development phase of a ball joint for fast and efficient optimization of the ball joint. all the shutter points. Defective sealing points can occur, for example, in a sealing bellows or in a housing cover. The inventive ball joint, however, has advantages not only in the development phase, but also in the series application, in comparison with conventional ball joints, since a damage of sealing points can be determined early, before The bearing capacity of the ball joint due to corrosion is affected. This increases the safety of the vehicle in a not insignificant way. It is also possible to reduce costs in a repair of the ball joint, because it will no longer be necessary - in all cases - to exchange the complete ball joint, since only one sealing bellows is damaged. By means of an early detection of the penetration of moisture and, with this, of the risk of corrosion, it may be sufficient, for example, to exchange only a defective sealing bellows when the surface of the ball head is not yet corroded. A non-corroded ball head will be regular, however, by quickly detecting the penetration of moisture into the ball joint, so that not only material costs can be saved, but also the investment in assembly may be less. The sensor can be connected to the cavity through an opening, provided in the housing, and be arranged on the outside of the housing itself.

Preferably, however, the humidity sensor is clamped on or inside the housing, particularly in the cavity. As ball joints frequently, in the region of the housing facing away from the bolt aperture, from a mounting aperture closed by a receiving cap, the humidity sensor is preferably arranged in the region of the housing that faces the opposite direction to the bolt opening. In this way, a simple mounting of the humidity sensor is allowed, since it can even be supported by the housing cover. According to a first alternative, the humidity in the ball joint is measured by the atmospheric humidity of the air surrounding the sensor, this passing through at least part of the cavity and / or in contact with each other reciprocal reaction with a lubricant present in the cavity. The atmospheric humidity measured in this air is a measure for the moisture fully penetrated into the interior of the ball joint, however, this air should not be mixed with the air in the atmosphere. If a lubricant is provided in the housing opening, then the humidity sensor must be separated from the lubricant to measure the atmospheric humidity so that the air can reach unimpeded to the sensor. For this purpose, a protective wall provided with through openings, preferably extending around a central wall region of the protective wall, can be arranged between the humidity sensor and the opening. The sensor may be disposed thereon on the face opposite the opening of the central wall region respectively being spaced from it relative to the opening. In addition, the air can circulate through the passage openings and enter into reciprocal reaction both with the humidity sensor and also with the lubricant disposed in the cavity. The humidity sensor can have two electrodes between which an electrically sensitive material is disposed to humidity. In particular, the humidity sensor is designed as a capacitive humidity sensor, wherein a moisture-sensitive dielectric, which can absorb moisture, is arranged in a gap between two electrodes. The amount of moisture absorbed by the dielectric depends on the humidity conditions in the immediate environment of the dielectric, being that the capacity of the humidity sensor changes depending on the amount of moisture absorbed by the dielectric. By measuring the capacity of the humidity sensor, the amount of moisture absorbed by the dielectric can be determined. A hygroscopic layer has turned out to be suitable for the dielectric, where preferred materials for the dielectric are polyamide or aluminum oxide, which may be shaped in particular in the form of a sheet. If a lubricant has been introduced into the socket of the ball joint, it is also possible, however, that the dielectric is formed by a part of this lubricant, the capacity of the humidity sensor varies depending on the amount of lubricant. moisture absorbed by the lubricant. The sensor is located in this, preferably, in a region of the ball joint where there is a frequent movement of the lubricant during the operation of the ball joint, so that on the one hand the gap between the electrodes is always full of lubricant , and on the other the lubricant present between the electrodes can be exchanged, thanks to this movement, with lubricant present outside the gap. The moisture content of the lubricant present between the electrodes measured, therefore, also represents the moisture content of the lubricant provided outside the gap and therefore the amount of total moisture penetrated into the cavity of the ball joint. The electrodes can have curved shapes, for example in the form of curved metal plates, where the gap filled with the dielectric is provided between The electrodes. In particular it is possible to fix the flat or curved electrodes in a material connection on a substrate, wherein layers applied by galvanizing on the substrate, respectively conductive lacquers, are suitable as electrodes. In case the ball head is arranged in the housing interposing a spherical shell, then it is possible for it to form the substrate for the electrodes. It is possible, however, also, that the substrate be formed by the box of a sensor subset, respectively that the electrodes are arranged in the box of a sensor subset, whereby a subset of the sensor is to be understood as an arrangement that, in addition to the humidity sensor itself, it comprises at least one box, preferably also an electronic circuit, which can perform, for example, a temperature compensation respectively compensation of crests for the signals measured by the sensor. The humidity sensor described above, comprising two electrodes, can be used, however, also for measuring the electrical conductivity of a moisture sensitive material, disposed between the electrodes, whose conductivity changes as a function of the amount of moisture absorbed by it. Therefore, also the measured conductivity of the material disposed between the electrodes is an appropriate magnitude to determine the amount of moisture penetrated into the cavity of the ball joint. As actual dielectrics also have an electrical conductivity regularly, it is also possible to use a dielectric of the aforementioned for this moisture-sensitive material. The invention is described below by preferred embodiments with reference to the drawing. In the drawing they show: Figure 1: a schematic section view of a first embodiment of the inventive swivel joint, Figure 2: a top view on the protective wall and the sensor according to Figure 1, Figure 3: a sectional view schematic of a second embodiment of the inventive swivel joint, Figure 4: an enlarged view of the detachable moisture sensor of Figure 3, Figure 5: a sectional view of the humidity sensor according to Figure 4, Figure 6: a view of schematic section of a third embodiment of the inventive swivel joint, Figure 7: a schematic view of a sensor subassembly, Figure 8: a sectional view of a moisture sensor with dielectric and Figure 9: a schematic sectional view of a fourth mode of the inventive knee joint. FIG. 1 shows a sectional view of a first embodiment of the inventive swivel joint, wherein a ball-and-socket joint 3 comprising a ball head 1 and a pin 2 is rotatably and pivotably housed in a cavity 4 in a ball joint housing 5. The ball stud 3 protrudes with its bolt 2 through a bolt opening 6 provided in the housing 5 thereof, the bolt opening 6 being protected by an elastic sealing bellows 7 against the penetration of moisture. On the opposite side of the pin 2, the housing 5 comprises an assembly opening 8 in which a protective wall 9 is arranged. The protective wall 9 rests, in this case, on a projection 10 that is formed on the inner wall 11 of the housing 5. The cavity 4 is filled with lubricant, so that the sliding properties of the ball head 1 on the ball are improved. housing 5 and the ball head 1 is protected to a large extent against corrosion. On the side facing away from the protective wall 9 is a humidity sensor 12 which is formed as an atmospheric humidity sensor with two electrodes and a hygroscopic layer located between them. The humidity sensor 12 is protected, in this, by a cover 13 held in the housing 5 against external agents undesirable as, for example, the free penetration of atmospheric air. Figure 2 shows a view from above on the protective wall 9 and the humidity sensor 12 which is disposed on or above a central region 14 of the protective wall 9. Around this central wall region 14 there are formed in the protective wall 9 several through openings 15 allowing the passage of air from the cavity 4 to the surrounding region of the humidity sensor 12 and in reverse, so that the air can circulate freely between the humidity sensor 12 and the cavity 4. The passage openings extend from the central wall region 14 to the side wall 16 of the protective wall 9, with two respectively contiguous passage openings extend a rib 17 connecting the central wall region 14 with the side wall 16. In the same way as the passage openings, the ribs 17 are also arranged around the central wall region 14 which protects the humidity sensor 12 formed as an atmospheric humidity sensor against contact with the lubricant. Figure 3 shows a sectional view of a second embodiment of the inventive swivel joint, with similar or similar characteristics designated with the same reference symbols as in the first modality. The humidity sensor 12 is formed, according to this embodiment, as a pair of curved metal plates that are curved on both sides towards the interior of the cavity 4 starting at the central longitudinal axis 18 of the ball joint. Figure 4 shows an enlarged view and Figure 5 a side view of the humidity sensor 12 according to Figure 3, with a slit 21 being provided between the metal plates 19 forming the pair of metal plates. A lubricant is introduced into the cavity 4, the slit 21 also being completely filled with the lubricant. Thanks to this arrangement and the conformation of. humidity sensor 12 is achieved that, when moving the ball head 1, a lubricant exchange occurs between the cavity 4 and the slit 21. Therefore, the moisture content of the lubricant present in the slit 21 represents the content of the moisture of the lubricant in the cavity 4. Figure 6 shows a schematic sectional view of a third embodiment of the inventive swivel joint, with the same or similar characteristics being designated with the same reference symbols as in the preceding embodiments. According to this embodiment, the ball head 1 is housed in the cavity 4 of the housing 5 using an intermediate spherical shell 25, wherein the electrodes of the humidity sensor 12 are formed by galvanic layers or conductive lacquers in the spherical shell. Also according to this embodiment, a lubricant is introduced into the cavity 4 that completely fills the gap formed between the electrodes. Figure 7 shows a subset of sensor that can replace the humidity sensor used in the preceding modes. According to this sensor sub-assembly, the humidity sensor 12 forms a constructive unit together with a sensor sub-assembly box 27 and an electronic circuit 26 which is disposed inside the sensor subassembly case 27 and which serves to process the information obtained by humidity sensor 12. The humidity sensor 12 is fastened, in this case, to the outer face of the sensor subassembly case 27. Figure 8 allows a sectional view of an applicable humidity sensor 12 to be appreciated, being that unlike Figure 5, the material 28 sensitive to the respective dielectric humidity introduced between the two electrodes 19 and 20 is shown, which may consist of , depending on the embodiment, of a hygroscopic layer, for example of polyamide, respectively aluminum oxide, or a lubricant. From Figure 9 a schematic sectional view of a fourth embodiment of the ball joint is apparent. inventive, being that the same or similar characteristics are designated with the same reference symbols as in the preceding modalities. According to this embodiment, a subset of the sensor, comprising a sensor subassembly box 27, is inserted into the spherical shell 25, the humidity sensor 12 being disposed in the sensor sub-assembly box 27 facing the ball head 1. Furthermore, according to this figure, the introduced lubricant 29 is sketched in the form of points, being that it also completely fills the gap present between the electrodes of the humidity sensor 12. Although in all embodiments a lubricant may be provided in the cavity 4, figures 1, 3, 5 and 6 of the lubricant representation have been dispensed with for reasons of clarity. According to figures 1, 3, 6 and 9, the humidity sensor 12 has contact with electrical conductors that are connected to an electronic processing unit 23, which is, according to figure 1, inside, and according to the figures 3, 6 and 9 on the outside of the ball joint. This processing unit 23 is connected, according to FIGS. 1 and 3, in addition to a signal transmitter 24 which is arranged inside the cabin of the motor vehicle and which informs the driver of the vehicle if the amount of humidity penetrated into the cavity 4 has exceeded an acceptable threshold value of humidity level. It is also possible, however, that the amount of humidity measured by the humidity sensor 12 in the cavity 4 is stored as electronic information in a memory provided in the processing unit 23, which can be consulted during a vehicle maintenance service automotive. In this case, the signal transmitter 24 can be dispensed with, as can be seen from FIGS. 6 and 9. List of reference symbols: 1 Ball head 2 pin 3 ball stud 4 cavity 5 housing 6 pin opening 7 sealing bellows elastic 8 assembly opening 9 protective wall 10 protrusion 11 internal wall 12 humidity sensor 13 cover 14 central wall region 15 passage opening 16 side wall 17 rib 18 central longitudinal axis 19, 20 metal plates / electrodes 21 slit 22 electrical conductors 23 electronic processing unit 24 signal emitter 25 spherical shell 26 'electronic circuit 27 sensor case 28 moisture sensitive material / dielectric 29 lubricant

Claims (16)

1. Ball joint for a motor vehicle comprising a ball and socket bolt, having a bolt and a ball head, which is arranged with its ball head in a rotary and pivoting manner in a cavity provided in a housing and protruding from this through a bolt aperture, and a sensor, characterized in that the sensor is a humidity sensor that is connected to the cavity.

Ball joint according to claim 1, characterized in that the humidity sensor is fixed in or on the housing.

Ball joint according to claim 1 or 2, characterized in that the humidity sensor is arranged in the cavity.

Ball joint according to one of the preceding claims, characterized in that the humidity sensor is arranged in the region of the housing facing away from the bolt opening.

Ball joint according to one of the preceding claims, characterized in that a protective wall provided with through openings is arranged between the humidity sensor and the cavity.

6. Ball joint according to claim 5, characterized in that the passage openings extend around a central wall region.

Ball joint according to one of the preceding claims, characterized in that the humidity sensor comprises two electrodes between which a material electrically sensitive to moisture is arranged.

Ball joint according to claim 7, characterized in that the moisture-sensitive material is a dielectric sensitive to moisture.

9. Ball joint according to claim 7 or 8, characterized in that the moisture sensitive material is formed by a hygroscopic layer.

Ball joint according to one of claims 7 to 9, characterized in that the moisture-sensitive material consists of polyamide sheet or aluminum oxide sheet.

Ball joint according to one of claims 7 to 9, characterized in that a lubricant is introduced into the cavity and the moisture sensitive material is formed at least in part by this lubricant.

Ball joint according to one of claims 7 to 11, characterized in that the electrodes are designed as curved metal plates.

13. Ball joint according to one of claims 7 to 12, characterized in that the electrodes are formed by galvanic layers or conductive lacquers. Ball joint according to one of the preceding claims, characterized in that the ball head is arranged in the housing with an intermediate spherical shell. Ball joint according to claim 14, characterized in that the humidity sensor is provided in the spherical shell. Ball joint according to one of Claims 1 to 14, characterized in that the humidity sensor is arranged in a sensor sub-assembly.