Sensor device for a ball joint

Abstract

Sensor device (104) for a ball joint (102) comprising a spherical shell (106) and a ball stud (108) rotatably mounted in the spherical shell (106), wherein the sensor device (104) comprises a sensor element (200) and a sensor element (202), wherein either the sensor element (202) or the sensor element (200) is integrated into the ball stud (108), characterized in that a partial area (204) of a ball stud surface (206) of the ball stud (108) is formed by the sensor element (202) or by the sensor element (200), wherein either the sensor element (202) or the sensor element (200) is integrated into the ball stud (108) such that a spherical surface of the ball stud (108) is continuous.

Description

[0001] The present invention relates to a sensor device for a ball joint.

[0002] Such a sensor device is known from DE 10 2008 041 050 A1. In this device, a sensor element is arranged in a pole face of a ball stud.

[0003] From DE 10 2010 030 246 A1 a sensor device is known in which rotationally asymmetrical recesses are introduced into the spherical surface of the ball stud, while a sensor is arranged between a magnet and the recesses in the area of ​​a housing cover.

[0004] A ball joint has three degrees of freedom about three axes of rotation, while linear movements are transmitted along all three axes. Rotations about any two of the axes result in a combined articulation angle of the ball joint. Measuring this combined articulation angle is difficult with conventional angle measuring systems.

[0005] Against this background, the present invention provides an improved sensor device for a ball joint, an improved method for manufacturing a sensor device, and an improved method for operating a sensor device according to the main claims. Advantageous embodiments are described in the dependent claims and the following description.

[0006] In an angle sensor for a ball joint that has two components—one located on the ball stud and the other on the ball socket—a linear relative movement of the ball stud to the ball socket can distort the measurement result. In other words, as the distance between the sensor and the object being measured increases, signal detection can deteriorate to the point where no signal detection is possible. In the approach presented here, the sensor element is in direct contact with the encoder element, with either the sensor element or the encoder element being integrated into the ball stud such that a continuous spherical surface of the ball stud is present.

[0007] In other words, the ball stud in the approach presented here has no flat spot.

[0008] A sensor device for a ball joint is presented, wherein the ball joint has a ball cup and a ball stud rotatably mounted in the ball cup, wherein the sensor device has a sensor element and a sensor element, wherein either the sensor element is integrated into the ball stud and a partial area of ​​a ball stud surface of the ball stud is formed by the sensor element, or the sensor element is integrated into the ball stud and the partial area is formed by the sensor element.

[0009] A sensor element can be, for example, a magnet, especially a permanent magnet. The sensor element can be, for example, a field line angle sensor.

[0010] A spring element can be arranged between the sensor element or encoder integrated into the ball stud and the ball stud itself. This spring element can be a spring that ensures continuous contact between the encoder and the sensor element. The spring element can compensate for movements between the ball stud and the ball socket within a tolerance range.

[0011] The portion of the ball stud surface can be flush with the ball stud surface if the stud spring element is at least partially compressed. The compressed stud spring element allows for a contact force that ensures uninterrupted contact.

[0012] Either the sensor element can be integrated into the spherical shell, with a section of the shell's surface formed by the sensor element, or the encoder element can be integrated into the spherical shell, with the section formed by the encoder element. This integration allows the spherical shell to be essentially spherical. The spherical shape minimizes linear motion.

[0013] A cup spring element can be arranged between the sensor element or encoder integrated into the ball cup and the ball cup itself. This cup spring element can be a spring that ensures continuous contact between the encoder and the sensor element. The cup spring element can compensate for movements between the ball stud and the ball cup within a specified tolerance range.

[0014] The section of the spherical shell surface can be flush with the spherical shell surface if the shell spring element is at least partially compressed. The compressed shell spring element can generate a contact force that ensures uninterrupted contact.

[0015] The encoder element can be configured to emit a magnetic field, at least during operation. The sensor element can be configured to represent the direction of the magnetic field lines in a directional signal. The encoder element can be an electromagnet or a coil. The sensor element can be a Hall sensor.

[0016] Furthermore, a method for manufacturing a sensor device is presented, wherein the method comprises a step of arranging a sensor element or a encoder element in a recess of a ball stud of a ball joint, wherein the sensor element or encoder element arranged in the recess forms a partial area of ​​a ball stud surface of the ball stud.

[0017] Furthermore, a method for operating a sensor device according to the approach presented here is introduced, wherein the method comprises the following steps: Reading a direction signal from a sensor element of the sensor device, wherein the direction signal represents a direction of magnetic field lines of a magnetic field of a sensor element; and

[0018] Determining an angle between the spherical shell and the ball stud using the direction signal.

[0019] It is also advantageous to have a computer program product with program code that can be stored on a machine-readable medium such as semiconductor memory, hard disk memory or optical memory and is used to carry out the method according to one of the embodiments described above when the program is executed on a computer or device. Fig. 1 a representation of a transverse control arm with a ball joint with a sensor device according to an embodiment of the present invention; Fig. 2 a sectional view of a ball joint with a sensor device according to an embodiment of the present invention; Fig. 3 a sketch of a ball joint with a tolerance-compensating sensor device according to an embodiment of the present invention; Fig. 4 a sectional view of a ball joint with a tolerance-compensating sensor device according to an embodiment of the present invention; Fig. 5 a sectional view of an inclined ball joint with a sensor device according to an embodiment of the present invention; Fig. 6 a flowchart of a method for manufacturing a sensor device according to an embodiment of the present invention; and Fig. 7 a flowchart of a method for operating a sensor device according to an embodiment of the present invention.

[0020] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, without repeating these elements.

[0021] Fig. Figure 1 shows a representation of a control arm 100 with a ball joint 102 and a sensor device 104 according to an embodiment of the present invention. The ball joint 102 has a ball socket 106 and a ball stud 108 rotatably mounted in the ball socket. The sensor device 104 is integrated into the ball joint 102 and registers an angle of articulation of the ball stud 108 in the ball socket 106 as an angle signal 110. In the installed state, the ball stud 108 is connected to a wheel carrier of a vehicle (not shown), while the control arm 100 is mounted on the vehicle via two control arm bearings 112.

[0022] The sensor device 104 can, for example, be part of a ride height sensor system for passenger cars and used to measure the suspension travel of the front and / or rear axle. Its installation in the ball joint 102 provides protection against environmental influences such as stone chips.

[0023] The sensor device 104 in the ball joint 102 enables additional functions to be performed. The condition or angular position of the chassis components 100 can be automatically detected. This information can then be integrated into the overall function for chassis dynamics. For example, the angular position can be used for headlight range control or headlight adjustment, roll stabilization, and / or for detecting mechanical wear.

[0024] In a conventional sensor, the object being measured, or rather the ball stud 108, moves dynamically. This makes measurements difficult or even impossible because the dynamic movement of the ball stud 108 can be transmitted to the measurement signal. Therefore, it is necessary to filter out this dynamic movement, as it interferes with the usable measurement signal.

[0025] The approach presented here involves decoupling the influence of disturbances so that these signals are largely eliminated during measurement signal acquisition.

[0026] Fig. Figure 2 shows a sectional view of a ball joint 102 with a sensor device 104 according to an embodiment of the present invention. The ball joint 102 essentially corresponds to the ball joint in Fig. 1. As in Fig. In Figure 1, the sensor device 104 is integrated into the ball joint 102. Here, a encoder element 200 is integrated into the ball cup 106, while a sensor element 202 is integrated into the ball stud 108. A portion 204 of the ball stud surface 206 is formed by the sensor element 202. Similarly, a section 208 of the ball cup surface 210 is formed by the encoder element 200.

[0027] The ball stud surface 206 and the spherical shell surface 210 are spherical and have essentially the same radius. A connecting line 212 for the sensor element 202 is integrated into a pin 214 of the ball stud 108.

[0028] The encoder element 200 is held in the spherical cup 106 by a cup spring element 216. The cup spring element 216 is designed here as an elastic cover 216. The cover 216 is made of a metal material and is pre-tensioned. This causes the cup spring element 216 to press the encoder element 200 onto the ball stud 108 with a pre-tensioning force. Thus, the encoder element 200 and the sensor element 202 remain in contact even if the ball stud 108 has play in the spherical cup 106.

[0029] The encoder element 200 can, for example, be a magnet, in particular a permanent magnet. The sensor element 202 can, for example, be a magnetic field angle sensor. The cover 216 can, for example, be made of aluminum, which enables improved signal acquisition. The Hall effect sensor can, for example, be used for measurement in the sensor element 202. In this case, a change in magnetic flux influences the magnetic field line pattern and its detection.

[0030] Fig. Figure 3 shows a sketch of a ball joint 102 with a tolerance-compensating sensor device 104 according to an embodiment of the present invention. The ball joint 102 essentially corresponds to the one described in the Fig. 1 to 2 ball joints are shown. In contrast, here the encoder element 200 is integrated into the ball stud 108, while the sensor element 202 is integrated into the spherical shell 106. The section 204 of the ball stud surface 206 is formed by the encoder element 200, and the section 208 of the spherical shell surface 210 is formed by the sensor element 202.

[0031] The encoder element 200 is arranged in a recess 300 of the ball stud 108. The recess 300 serves as an axial bearing for the encoder element 200. A pin spring element 302 is arranged between the encoder element 200 and the ball stud 108. The pin spring element 302 is arranged in the recess 300. Here, the pin spring element 302 is designed as stacked disc springs. The pin spring element 302 can, for example, also be designed as a coil spring or an elastomer.

[0032] In the illustrated state, the spherical surface of the encoder element 200 is flush with the ball stud surface 206. The stud spring element 302 is under preload. The encoder element 200 and the ball stud 108 are separated by a gap 304, allowing the encoder element 200 to compress further into the recess 300 to compensate for tolerances.

[0033] Due to wear 306 of the ball socket 106, the ball stud 108 can perform an unintended linear movement 308 within the ball socket 106 under load. The gap 304 is so large that the encoder element 200 compensates for the movement 308 via the stud spring element 302. This ensures that the sensor element 202 remains in contact with the encoder element 200 even during the movement 308.

[0034] In other words, the sensor element 202 has direct contact with the ball. The pin spring element 302 serves to compensate for tolerances resulting from an increase in the elasticity of the ball joint 102 due to wear 306. This achieves a largely complete decoupling of the sensor device 104 from the ball joint function, minimizing disturbances in the measuring system.

[0035] Fig. Figure 4 shows a sectional view of a ball joint 102 with a tolerance-compensating sensor device 104 according to an embodiment of the present invention. The ball joint 102 and the sensor device 104 essentially correspond to the illustration in Figure 4. Fig. 3. In contrast, the recess 300 is designed here as a cylindrical bore in the ball stud 108. In addition, the sensor element 202 is installed in a cover 216 designed as a shell spring element 216, as shown in Fig. 2 integrated. The sensor element 202 is contacted via a connector 400 and a cable 402. The connector 400 is mechanically connected to the cover 216.

[0036] Fig. Figure 5 shows a sectional view of an inclined ball joint 102 with a sensor device 104 according to an embodiment of the present invention. The ball joint 102 and the sensor device 104 essentially correspond to the illustration in Figure 5. Fig. 4. Here, the ball stud 108 with the encoder element 200 is rotated by an angle 500 relative to the ball cup 106.

[0037] The rotation causes the encoder element 200 to pivot laterally relative to the sensor element 202. The direction of the magnetic field lines of a magnetic field emitted by the encoder element 200 is changed by an angle of 50°. The sensor element 202 detects the direction of the magnetic field lines and represents them in a direction signal 502. The sensor device 104 includes a detection unit 504 arranged in the connector 400. Using the direction signal 502, the detection unit 504 determines an angle signal 110 representing the angle 50°.

[0038] Fig. Figure 6 shows a flowchart of a method 600 for manufacturing a sensor device according to an embodiment of the present invention. The method 600 comprises a step 602 of arranging, in which a sensor element or an encoder element is arranged in a recess of a ball stud of a ball joint. The sensor element or encoder element arranged in the recess forms a partial region of a ball stud surface of the ball stud.

[0039] Fig.Figure 7 shows a flowchart of a method 700 for operating a sensor device according to an embodiment of the present invention. The method 700 comprises a reading step 702 and a determination step 704. In reading step 702, a direction signal is read from a sensor element of the sensor device. The direction signal represents the direction of magnetic field lines of a magnetic field of a sensor element. In determination step 704, an angle between the spherical shell and the ball stud is determined using the direction signal.

[0040] The embodiments described and shown in the figures are only examples. Different embodiments can be combined completely or with respect to individual features. An embodiment can also be supplemented by features from another embodiment.

[0041] Furthermore, the process steps according to the invention can be repeated and carried out in a different order than described.

[0042] If an embodiment includes an “and / or” connection between a first feature and a second feature, this can be interpreted as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature. Reference sign 100 wishbones 102 Ball joint 104 Sensor device 106 Spherical bowl 108 ball studs 110 angle signal 112 Control arm bearings 200 transmitter element 202 Sensor element 204 Sub-area 206 Ball stud surface Section 208 210 spherical shell surface 212 Connection line 214 cones 216 Shell spring element, lid 300 recess 302 Pin spring element 304 gap 306 Wear 308 Movement 400 plugs 402 cables 500 angles 502 Directional signal 504 Investigation Unit 600 manufacturing processes Step 602 of the arranging process 700 procedures for operating Step 702 of the reading process Step 704 of the determination process

Claims

[1] Sensor device (104) for a ball joint (102) comprising a ball cup (106) and a ball stud (108) rotatably mounted in the ball cup (106), wherein the sensor device (104) comprises a sensor element (200) and a sensor element (202), wherein either the sensor element (202) or the sensor element (200) is integrated into the ball stud (108), characterized by , that a partial area (204) of a ball stud surface (206) of the ball stud (108) is formed by the sensor element (202) or by the encoder element (200), wherein either the sensor element (202) or the encoder element (200) is integrated into the ball stud (108) such that a spherical surface of the ball stud (108) is continuous. [2] Sensor device (104) according to claim 1, in which a pin spring element (302) is arranged between the sensor element (202) or encoder element (200) integrated in the ball stud (108) and the ball stud (108). [3] Sensor device (104) according to claim 2, wherein the partial area (204) of the ball stud surface (206) is flush with the ball stud surface (206) when the stud spring element (302) is at least partially compressed. [4] Sensor device (104) according to one of the preceding claims, in which either the sensor element (202) is integrated into the spherical shell (106) and a section (208) of a spherical shell surface (210) of the spherical shell (106) is formed by the sensor element (202) or the encoder element (200) is integrated into the spherical shell (106) and the section (208) is formed by the encoder element (200). [5] Sensor device (104) according to claim 4, in which a shell spring element (216) is arranged between the sensor element (202) or encoder element (200) integrated in the spherical shell (106) and the spherical shell (106). [6] Sensor device (104) according to claim 5, wherein the section (208) of the spherical shell surface (210) is flush with the spherical shell surface (210) when the shell spring element (216) is at least partially compressed. [7] Sensor device (104) according to one of the preceding claims, wherein the encoder element (200) is configured to emit a magnetic field at least during operation and the sensor element (202) is configured to map a direction of magnetic field lines of the magnetic field in a direction signal (502). [8] Method (600) for manufacturing a sensor device (104) according to any one of claims 1 to 7, wherein the method (600) comprises a step (602) of arranging a sensor element (202) or a sensor element (200) in a recess (300) of a ball stud (108) of a ball joint (102), wherein the sensor element (202) or sensor element (200) arranged in the recess (300) forms a partial area (204) of a ball stud surface (206) of the ball stud (108). [9] Method (700) for operating a sensor device (104) according to any one of claims 1 to 7, wherein the method (700) comprises the following steps: Reading (702) a direction signal (502) from a sensor element (202) of the sensor device (104), wherein the direction signal (502) represents a direction of magnetic field lines of a magnetic field of a sensor element (200); and Determine (704) an angle (500) between the spherical shell (106) and the ball stud (108) using the direction signal (502).

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