Joint with a sensor device for determining a relative position of a joint inner part in relation to a joint housing and method for determining a relative position in a joint according to the invention.

Abstract

The invention relates to a joint (1) with a sensor device (14) for determining the relative position of an inner joint part (2) with respect to a joint housing (3), wherein the inner joint part (2) is movably mounted in the joint housing (3) and the sensor device (14) is arranged on the joint housing (3). A joint (1) with an improved sensor device (14) is provided, in which the sensor device (14) has an image sensor (18) for receiving light rays reflected from the inner joint part (2), wherein the image sensor (18) detects the relative position of an orientation pattern (19, 20) formed on the inner joint part (2).

Description

The invention relates to a joint with a sensor device for determining the relative position of an inner joint part in relation to a joint housing, wherein the inner joint part is movably mounted in the joint housing and the sensor device is arranged on the joint housing. Furthermore, the invention relates to a method for determining the relative position of an inner joint part in relation to a joint housing in the aforementioned joint, wherein the relative position is determined by means of a sensor device. Such a joint is known from DE 10 2004 053 690 A1 in the form of a ball joint. According to a first embodiment, a ball joint of the inner part of the joint has a magnet that interacts with the sensor device, the sensor device being a magnetoresistive sensor. According to a further embodiment, the sensor device has means for optical angle detection, with further details not mentioned. From US 5 416 392 A a ball joint for a robotic joint is known in which a grid is applied to the spherical surface of the joint ball, wherein the position of the grid is detected with an image sensor and the position of the joint can be determined thereby. A disadvantage of a sensor device with a magnet in the ball joint of the inner joint component is that the inner joint component must be machined to accommodate the magnet. The spherical shape of the ball joint can be affected or interrupted by the magnet's placement, which, without adequate countermeasures, can lead to limitations in the joint's usability and / or lifespan. The object underlying the invention is to further develop a joint and a method of the type mentioned above in such a way that a joint with an improved sensor device is provided. Preferably, the manufacturing of the ball stud with the sensor device should be simplified and / or made more cost-effective. In particular, an alternative embodiment should be provided. The problem underlying the invention is solved by a joint according to claim 1 and by means of a method according to claim 9. Preferred embodiments of the invention are found in the dependent claims and in the following description. The joint is designed for use in a vehicle's chassis. Specifically, the joint is designed as a ball joint. Joints can be used in a variety of ways in vehicle construction. In the chassis, a ball joint, in particular, serves to connect chassis components such as control arms, wheel carriers, tie rods, or similar parts to each other or to the vehicle body or an attached axle carrier. Alternatively, the joint can be designed as a rubber joint, a linear joint, or a translational joint. In a linear or translational joint, the inner part of the joint and the joint housing can be movable or slid relative to each other along a fixed axis. The joint incorporates a sensor device for determining the relative position of an inner joint component with respect to a joint housing. The inner joint component is movably mounted within the joint housing. The inner joint component can be designed as a ball stud or a ball sleeve. Accordingly, the joint or ball joint can be implemented as a ball stud joint or a ball sleeve joint. The joint housing may have a housing recess that is open on at least one side. In particular, a ball joint of the inner joint part is pivotally and / or rotatably mounted in the housing recess with respect to the joint housing or a central longitudinal axis of the joint housing. A pin of the inner joint part may protrude from a housing opening of the joint housing. A bearing shell, particularly made of plastic, may be arranged between the joint housing and the ball joint of the inner joint part. By means of the bearing shell, friction and thus wear of the joint can be reduced despite the sometimes high operational loads. The sensor device is arranged on the joint housing. According to the invention, the sensor device comprises an image sensor for receiving light rays reflected from the inner part of the joint, in particular from the transmitter. The image sensor detects the relative position of an orientation pattern formed on the inner part of the joint. Specifically, the image sensor captures an image of the relative position of the orientation pattern. A key advantage is that the sensor device does not require an active signal from the inner joint component. Instead, it utilizes an optically detectable orientation pattern, which is captured and / or recorded by the image sensor. This eliminates the need for a magnet on the inner joint component. In particular, the design of the ball joint of the inner joint component is not negatively affected by the presence of a magnet. By eliminating the magnet and using an image sensor, unwanted interference from magnetic fields and / or temperature fluctuations is avoided. Manufacturing the joint with the sensor device is simplified and becomes more cost-effective. In particular, a relative position and / or angular position of the inner joint part with respect to the joint housing and / or a central longitudinal axis of the joint housing is determined by means of an evaluation device and based on the detected position of the orientation pattern and / or an image of the orientation pattern. Preferably, the image sensor captures an image of the orientation pattern. Preferably, the image sensor continuously and / or at a predetermined sampling rate captures the orientation pattern and / or images of the orientation pattern. During a rotational and / or tilting movement of the inner joint part, the orientation pattern also shifts with respect to the image sensor. This results in images that differ from one another and depend on the relative position of the inner joint part with respect to the joint housing and / or the image sensor.Based on an evaluation and / or a comparison of the captured images with reference images stored, in particular in the evaluation device, the relative position and / or angular position of the inner part of the joint can be determined. The evaluation device may include at least one image processing chip. In particular, the evaluation device has at least one memory element or several memory elements. The memory element may be designed as flash memory. Furthermore, the evaluation device may include a chip for signal processing and / or signal transmission to a control unit. In particular, active chassis components of a vehicle chassis can be controlled by means of the control unit. Preferably, the sensor device includes a transmitter for emitting light beams. In particular, the transmitter and / or the light beams are directed towards the inner part of the joint, preferably towards a section of a surface of the inner part of the joint. Specifically, the light beams directly strike the intended section of the surface of the inner part of the joint. According to a further embodiment, the transmitter is designed as an infrared light transmitter. In particular, the transmitter includes infrared diodes for emitting infrared light. Such an infrared light transmitter is inexpensive to procure and at the same time reliable and durable. Preferably, the image sensor is configured as an infrared pixel sensor, particularly an active one. The image sensor or infrared pixel sensor can be a CMOS sensor. The infrared pixel sensor can interact with an infrared light emitter. In particular, the infrared pixel sensor detects infrared light reflected from the orientation pattern. An infrared pixel sensor is reliable, durable, and inexpensive to procure. In a further embodiment, the sensor device comprises a sensor housing in which the transmitter and the image sensor are arranged. This results in a compact design for the sensor device, in which the transmitter and the image sensor are arranged and / or combined in a single sensor housing. This simplifies the mounting of the sensor device on the joint housing. In particular, the sensor housing is secured in a sensor housing receptacle of the joint housing. The sensor housing receptacle can be designed as a recess, a cutout, or a blind hole in the joint housing. For example, the sensor housing is glued into the sensor housing receptacle. The sensor device can be arranged in the region of an edge of the joint housing. The edge of the joint housing can surround and / or define a housing opening of the joint housing. In particular, the inner joint part extends outwards from the joint housing and through the housing opening. Thus, the inner joint part passes over the edge and the sensor device arranged in the region of the edge. Preferably, the sensor device is arranged at least partially within a sealing chamber of the joint. Here, the sealing chamber is formed and / or closed and / or sealed by means of the inner joint part, the edge of the joint housing, and a sealing bellows. In other words, the sealing chamber represents an enclosed free space. In particular, the transmitter and the image sensor of the sensor device are oriented towards the sealing chamber and / or the inner joint part.Due to the arrangement of the sensor device, preferably the transmitter and image sensor, in the sealing chamber of the joint, it is reliably protected from environmental influences. Alternatively, the sensor device can be arranged in the area of ​​the housing recess, particularly outside the sealing area, so that the transmitter and the image sensor are directed towards a surface of the ball joint of the inner joint part with the orientation pattern. For example, if the inner joint part is a ball stud, the sensor device can be arranged on the joint housing in an area facing away from a stud of the inner joint part. According to a further embodiment, it is conceivable that the sensor device is arranged in a housing cover of the joint housing. In particular, the transmitter and the image sensor are directed towards a surface of the joint ball of the inner joint part with the orientation pattern by means of a clearance in the joint housing. According to the invention, the orientation pattern is formed on a section of a pin or pin neck of the inner part of the joint. It must be ensured that the orientation pattern is illuminated by the light from the transmitter and that the radiation reflected by the orientation pattern can be detected by the image sensor. In another embodiment, the orientation pattern is formed by means of grooves resulting from the manufacturing of the inner joint component. In particular, the grooves are realized as milling grooves and / or turning grooves. For example, the grooves result from cylindrical grinding and / or cylindrical turning of the ball joint of the inner joint component. The shape of the grooves, and thus the orientation pattern, can be unique for each inner joint component. Therefore, it may be necessary to individually calibrate the sensor device for each inner joint component or joint. Since the grooves are automatically formed during the manufacturing of the inner joint component, a separate manufacturing step for generating the grooves and / or the orientation pattern can be omitted. Alternatively or additionally, the orientation pattern can be produced as an optically detectable surface pattern in a section of the joint's inner surface using a marking process. In particular, if the grooves resulting from the manufacturing of the joint's inner surface are insufficient to provide an orientation pattern, an orientation pattern can be artificially generated and provided using a separate marking process. For example, a laser can be used in this marking process to create the optically detectable surface pattern for the orientation pattern in a section of the joint's inner surface. Of particular advantage is a method for determining a relative position of the inner part of the joint in relation to the joint housing in a joint according to the invention, wherein the relative position is determined by means of the sensor device. In particular, light beams are emitted by the transmitter of the sensor device. The image sensor of the sensor device receives light beams reflected from the inner joint part, thereby capturing a relative position of the orientation pattern formed on the inner joint part and on a section of a pin or pin neck of the inner joint part, in particular an image of the relative position of the orientation pattern. Preferably, the method is further developed according to the embodiments described herein in connection with the joint according to the invention. Furthermore, the joint described herein can be further developed according to the embodiments described herein in connection with the method. The invention is explained in more detail below with reference to the figures. Figure 1 shows a sectional side view of a joint according to the invention. Fig. 1 shows a sectional side view of a joint 1 according to the invention. In this embodiment, the joint 1 is designed as a ball joint, specifically a ball-and-socket joint. The joint 1 comprises an inner joint part 2 and a joint housing 3. The joint housing 3 is shown here by way of example as an integral component of a chassis component. Alternatively, the joint housing can be designed as a separate component, which, for example, is pressed into a corresponding receptacle of a chassis component. In this example, the inner joint part 2 is designed as a ball stud. Accordingly, the inner joint part 2 has a ball 4 and a pin 5 extending away from the ball 4. The inner joint part 2 is movably mounted in the joint housing 3. For this purpose, in this embodiment, the joint housing 3 has a housing recess 6, wherein the ball 4 is mounted so as to tilt and / or rotate freely in the housing recess 6. In this example, a bearing shell 7 is arranged in the housing recess 6 and fixed to the joint housing 3, with the ball 4 being received in the bearing shell 7. The joint housing 3 has a housing opening 8 from which the inner joint part 2 with its pin 5 extends outwards from the housing recess 6. A rim 9 of the joint housing 3 surrounds or limits the housing opening 8. The joint 1 has or forms a sealing chamber 10. The sealing chamber 10 is formed by the inner joint part 2, the edge 9 of the joint housing 3, and a sealing bellows 11, and is sealed against the external environment. The sealing bellows 11 extends from a region of the edge 9 to the pin 5 of the inner joint part 2. In this embodiment, the joint housing 3 has a further housing opening 12 on a side facing away from the housing opening 8 and the pin 5. This further housing opening 12 is closed by means of a cover 13. The joint 1 has a sensor device 14. The sensor device 14 is arranged and attached to the joint housing 3 in the region of the edge 9. In this embodiment, the sensor device 14 is arranged in the sealing chamber 10. The sensor device 14 has a sensor housing 15, which is arranged in a sensor housing receptacle 16 of the joint housing 3. The sensor device 14 has a transmitter 17 and an image sensor 18. In this embodiment, the transmitter 17 and the image sensor 18 are arranged in the sensor housing 15 and directed towards the inner joint part 2. In this example, the transmitter 17 is designed as an infrared light transmitter for emitting infrared light. Accordingly, the image sensor 18 is designed as an active infrared pixel sensor. In this embodiment, the inner joint part 2 has a schematically indicated orientation pattern 19 and a schematically indicated further orientation pattern 20. The orientation pattern 19 is formed on a section of a spherical surface of the joint ball 4. In this example, the orientation pattern 19 is formed by means of grooves resulting from the manufacturing of the inner joint part 2. In particular, the grooves result from milling and / or turning of the joint ball 4. In this example, the additional orientation pattern 20 is formed on a section of the pin 5 that lies within the sealing chamber 10. In this embodiment, the additional orientation pattern 20 is produced in a separate manufacturing step using a marking process. For example, if the manufacturing-related grooves resulting from the production of the inner joint part 2 are insufficient to provide a sufficiently optically detectable orientation pattern, the additional orientation pattern 20 can be artificially generated and provided using a separate marking process. For example, a laser can be used in the marking process to produce the optically detectable additional surface pattern 20 in the section of the surface of the inner joint part 2. The positions of orientation patterns 19 and 20 can be reversed in the arrangement shown here. Alternatively, either only orientation pattern 19 or only the additional orientation pattern 20 can be formed and / or used. The image sensor 18 can detect the relative position of the orientation pattern 19 and / or 20 formed on the inner part 2 of the joint. In this example, the image sensor 18, which is designed as an infrared pixel sensor, detects the infrared light emitted by the transmitter 17 and reflected by the orientation pattern 19 and / or 20. The sensor device 14 is connected to an evaluation device 21 by means of a line not shown in detail here. Using the evaluation device 21 and based on the detected position of the orientation pattern 19 and / or 20, or an image of the orientation pattern 19 and / or 20 captured by the image sensor 18, the relative position and / or angular position of the inner joint part 2 with respect to the joint housing 3 can be determined. For this purpose, the image sensor 18 continuously and / or at a predefined sampling rate detects the orientation pattern 19 and / or 20. During a rotational and / or tilting movement of the inner joint part 2, the orientation pattern 19 and / or 20 also shifts with respect to the image sensor 18. This results in images that differ from one another and depend on the relative position of the inner joint part 2 with respect to the joint housing 3 or the image sensor 18.Based on an evaluation and / or a comparison of the images captured by the image sensor 18 with reference images stored, for example, in the evaluation device 21, the relative position and / or angular position of the inner part of the joint 2 in relation to the joint housing 3 can be determined. Reference sign 1 Joint 2 Inner joint part 3 Joint housing 4 Ball joint 5 Pin 6 Housing recess 7 Bearing shell 8 Housing opening 9 Edge 10 Sealing chamber 11 Sealing bellows 12 Further housing opening 13 Cover plate 14 Sensor device 15 Sensor housing 16 Sensor housing receptacle 17 Transmitter 18 Image sensor 19 Orientation pattern 20 Orientation pattern 21 Evaluation device

Claims

The joint is designed for use in a vehicle chassis and has a sensor device (14) for determining a relative position of an inner joint part (2) in relation to a joint housing (3), wherein the inner joint part (2) is movably mounted in the joint housing (3) and the sensor device (14) is arranged on the joint housing (3), characterized in that the sensor device (14) has an image sensor (18) for receiving light rays reflected from the inner joint part (2), wherein the image sensor (18) detects a relative position of an orientation pattern (19, 20) formed on the inner joint part (2), and the orientation pattern (19, 20) is formed on a section of a pin (5) or pin neck of the inner joint part (2). Joint according to claim 1, characterized in that a relative position and / or angular position of the inner part of the joint (2) in relation to the joint housing (3) and / or a central longitudinal axis of the joint housing (3) is determined by means of an evaluation device (21) and on the basis of the detected position of the orientation pattern (19, 20). Joint according to claim 1 or 2, characterized in that the sensor device (14) has a transmitter (17) for emitting light beams, in particular the transmitter (17) is designed as an infrared light transmitter. joint according to one of the preceding claims, characterized in that the image sensor (18) is designed as an, in particular active, infrared pixel sensor, preferably a CMOS sensor. Joint according to one of the preceding claims, characterized in that the sensor device (14) has a sensor housing (15), wherein the transmitter (17) and the image sensor (18) are arranged in the sensor housing (15), in particular the sensor housing (15) is attached in a sensor housing receptacle (16) of the joint housing (3). Joint according to one of the preceding claims, characterized in that the sensor device (14) is arranged in the region of an edge (9) of the joint housing (3), in particular the sensor device (14) is arranged at least partially in a sealing chamber (10) of the joint (1), wherein the sealing chamber (10) is formed by means of the joint inner part (2), the edge (9) of the joint housing (3) and a sealing bellows (11), preferably the transmitter (17) and the image sensor (18) of the sensor device (14) are oriented in the direction of the sealing chamber (10) and the joint inner part (2). Joint according to one of the preceding claims, characterized in that the orientation pattern (19) is formed by means of grooves resulting from the manufacture of the inner part of the joint (2), in particular the grooves are formed as milling grooves and / or turning grooves. Joint according to one of the preceding claims, characterized in that the orientation pattern (20) is produced as an optically detectable surface pattern by means of a marking method in an area of ​​the surface of the inner part of the joint (2). Method for determining a relative position of a joint inner part (2) in relation to a joint housing (3) of a joint (1) according to one of the preceding claims, wherein the relative position is determined by means of a sensor device (14), characterized in that light rays reflected from the joint inner part (2) are received by means of an image sensor (18) of the sensor device (14), wherein a relative position of an orientation pattern (19, 20) formed on the joint inner part (2) and on a section of a pin (5) or pin neck of the joint inner part (2) is detected.

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