Sensor device for detecting rotational speed

Abstract

The invention relates to a sensor device (10) for detecting rotational speed, wherein the sensor device (10) comprises a sensor (12) for detecting the rotational speed of a rotating body about a rotational axis (20) and a housing (18). The housing (18) extends with a base body in a ground plane (Gv). The housing has an inner surface (24) and an opposite outer surface (26). The sensor (12) has a leadframe (14), a sensor element (44) arranged on the leadframe (14), and an electrical connection (16) arranged thereon for supplying power to the sensor. The leadframe (14) is at a defined distance (R) SThe leadframe (14) is arranged on the inside (24) of the housing (18) and is parallel to the axis of rotation (20). It extends from the outside (26) of the sensor (12) on a side adjacent to the ground plane (Gv). The electrical connection (16) is divided into a first section (38), a second section (40), and a third section (42). The first section (38) extends from the leadframe (14) into the housing (18). The second section (40) extends at a 90° angle from the first section towards the axis of rotation (20). The third section (42) extends from the second section at an angle between 0° and 45°.

Description

[0001] The invention relates to a sensor device for detecting rotational speed.

[0002] Modern vehicles are equipped with a variety of sensors to make driving safer and more comfortable. Among these sensors are wheel speed sensors, which measure the rotation of a wheel. The measured wheel speed is used, for example, in anti-lock braking systems (ABS), which prevent the wheels from locking up by reducing brake pressure. The sensor device consists of a sensor and a sensor element. The sensor element is usually a disc with permanent magnets arranged with alternating north and south poles around its circumference.

[0003] There are two basic methods for installing the wheel speed sensor in a vehicle. In one method, the sensor is inserted into a bore in the steering knuckle and positioned according to the encoder element. In the other method, the sensor, which is housed in a casing, is mounted on one side of the wheel bearing. The encoder element is attached to a shaft or similar component. The sensor is manufactured in several steps, resulting in a ready-to-install sensor at the end of the production process.

[0004] The invention is based on the objective of proposing a sensor device for detecting rotational speed which has a low complexity in the manufacturing process and / or enables the production of a more cost-effective sensor device.

[0005] To solve the problem, a sensor device for detecting rotational speed is provided. The sensor device comprises a sensor for detecting the rotational speed of a rotating body about an axis of rotation, as well as a housing. The housing, along with a base body, lies in a plane. The housing has an inner and an opposite outer surface. The sensor has a leadframe, a sensor element mounted on the leadframe, and an electrical connection for supplying power to the sensor. The leadframe is located on the inner surface of the housing at a defined distance from the axis of rotation. The leadframe extends parallel to the axis of rotation from the outer surface of the sensor on a side adjacent to the plane of rotation. The side of the sensor extends perpendicular to the axis of rotation. The electrical connection is divided into a first section, a second section, and a third section.The first section extends from the leadframe into the housing. The second section extends at a 90° angle from the first section towards the axis of rotation. The third section extends in a direction at an angle between 0° and 45° from the second section.

[0006] The term sensor device refers to a device comprising a sensor with a sensor element for detecting rotational speed and a housing in which the sensor is arranged.

[0007] The axis of rotation is understood to be the axis which lies at the center of the casing, which is circular in its base, and around which a body of revolution rotates.

[0008] A body of revolution is understood to be a body that moves around its axis of rotation with a rotational motion. The body of revolution is preferably designed as a wave.

[0009] The term "base body" refers to the body from which further elements of the sensor device extend or encompass further elements of the sensor device. The base body forms a base surface of the sensor device. The base body is preferably circular or radial. The base body has an inner surface and an opposing outer surface. An electrical connection is arranged on the outer surface. A sensor is arranged on the inner surface. The base body lies in a plane that is essentially perpendicular to the axis of rotation.

[0010] A leadframe is a metallic conductor carrier formed from two separate electrical conductors. The leadframe serves as the electrical connection for the sensor element. A capacitor, particularly a coupling capacitor, can be arranged between the two electrical conductors. The leadframe is preferably made of copper.

[0011] The term "sensor element" refers to the element comprising an electronic circuit designed to detect a physical quantity, in particular a magnetic field. The magnetic field is generated by a circular encoder element mounted on the rotating body. Permanent magnets with alternating north and south polarity are arranged on the encoder element at defined distances and within a defined radius. The electronic circuit detects changes in the magnetic field over time and generates an analog output signal. The sensor element is preferably an AMR, GMR, or Hall sensor. The encoder element is preferably an encoder disk.

[0012] The electrical connection is understood to be the connection through which an electrical conductor can be connected, supplying the sensor element with an electrical voltage and designed for data transmission. The electrical connection extends, in particular, from the leadframe, which is enclosed within the housing, to a point outside the housing. The electrical connection is preferably made of copper.

[0013] The advantage of the invention lies in the fact that the manufacturing process of the sensor device is simplified, thereby reducing production costs. This is because the sensor device eliminates the need for a carrier element that encloses the sensor and serves to fix it in an injection mold. Thus, a production step and the carrier element are eliminated, reducing costs and simplifying production.

[0014] Preferably, the sensor has a sensor housing. The sensor housing at least partially surrounds the sensor element and the leadframe that supports the sensor element. On a side of the sensor housing adjacent to the base plane, the leadframe protrudes from the sensor housing in the form of two electrical conductors. The sensor housing is preferably made of a polymer, in particular polyurethane. This protects the sensor element from environmental influences such as dirt and / or moisture.

[0015] The sensor housing preferably has a recess on a first side, which is a sensor housing base. The first side is perpendicular to the base body of the sensor device and extends away from the inside. The recess on the first side of the sensor housing is designed such that a tool, for example one with a rectangular protrusion corresponding to the recess, can engage in the recess during the manufacturing process. The sensor housing base is preferably rectangular, and in particular square. This has the advantage of allowing for easy fixation during the manufacturing process of the sensor device.

[0016] Furthermore, the sensor housing has a raised section on a second side, opposite the first. This section can be rectangular, round, or X-shaped. The raised section is designed to allow a tool to fix the sensor device in place during the manufacturing process. For example, the tool might have a rectangular recess corresponding to the raised section. This offers the advantage of easy fixation during the manufacturing process.

[0017] Preferably, the leadframe and the first section of the electrical connection can be welded or crimped together. The electrical connection is positioned on the leadframe, for example using a tool, in particular a gripper arm, such that a section of the leadframe and a section of the electrical connection overlap. Preferably, the leadframe and the electrical connection are welded together in the overlapping area, for example by ultrasonic welding or laser welding. Alternatively, the overlapping area is joined together by a joining process involving plastic deformation, in particular crimping. This has the advantage that the leadframe and the electrical connection are mechanically firmly connected.

[0018] Furthermore, the sensor features a connector receptacle on the outside of the housing, into which the third section projects. The connector receptacle is designed to accept a connector. An electrical conductor, used for power supply and / or data transmission, is attached to the connector. The connector receptacle preferably also has first locking devices that allow it to engage with second locking devices arranged on the connector, thus creating a positive connection with the housing. The connector receptacle offers the advantage that the sensor device can be powered and data, particularly to a control unit, can be transmitted. The connector receptacle provides a standardized interface.

[0019] Preferably, the housing includes at least one pocket for the sensor, the pocket at least partially surrounding the sensor housing. The pocket is designed such that the sensor is securely positioned within the housing. The pocket preferably has an opening on the first side of the sensor housing, which is created during the manufacturing process of the sensor device. This has the advantage that the sensor is firmly positioned and additionally protected within the housing.

[0020] Furthermore, the housing is cup-shaped, with a structure extending from the inside of the housing to form a receiving chamber, the sensor being located on the inside of the housing. The cup-shaped form is achieved by extending a structure, in particular a rim, from the inside of the housing at a distance greater than the defined distance of the sensor, extending around the entire circumference of the housing. Within this structure, a receiving chamber is formed, which serves to receive the rotating body. This has the advantage that the housing can be positioned in a freely accessible area of ​​the rotating body.

[0021] A fixing element is preferably included at the edge of the receiving space. This fixing element secures the housing at a fixing point in the immediate vicinity of the rotating body, for example, an outer ring of a bearing in which the rotating body is mounted. The fixing element creates a force-fit and form-fit connection on a surface of the fixing point. Furthermore, the fixing element can protect against the ingress of moisture and / or dirt. This has the advantage of ensuring a secure mounting of the sensor device and protecting the sensor from environmental influences.

[0022] Furthermore, a method for manufacturing a sensor device described above is provided to solve the problem, wherein the sensor device comprises a sensor, a housing, a leadframe and an electrical connection, comprising the following steps: • Fixing the sensor with a tool • Connecting the leadframe to the electrical connection by welding or crimping • Inserting a fixing agent into the tool • Creating the housing that at least partially surrounds the sensor, the electrical connection, and the fixing agent.

[0023] Further features and advantages will become apparent from the following description in conjunction with the accompanying drawings. These show: Fig. 1 a sectional view of the sensor device; Fig. 2 a perspective view of the sensor device according to Fig. 1; and Fig. 3 the process steps of the manufacturing process.

[0024] In Fig. Figure 1 shows a sensor device 10. The sensor device 10 comprises a sensor 12, a leadframe 14, an electrical connection 16, and a housing 18. A rotation axis 20 is located at the center of the housing. A rotating body (not shown) with an encoder element attached to it rotates about the rotation axis 20. The encoder element comprises a plurality of encoder elements. The encoder elements are preferably permanent magnets and are arranged with alternating north and south polarity in a circular path on the rotating body. The sensor 12 is located on the inner side 24 of the housing. The connector receptacle 22 is located on the outer side 26 of the housing.

[0025] On the inside 24 of the housing 18, at a defined distance R, SThe sensor 12 is arranged. The sensor 12 comprises a sensor element 44, a leadframe 14, and a sensor housing (reference symbol?) surrounding the sensor element 44 and the leadframe. The sensor housing protects the sensor element and the leadframe from environmental influences such as moisture and dirt. The sensor 12 is also at least partially surrounded by the housing 18.

[0026] The sensor element 44 is arranged on the leadframe 14. The leadframe 14 serves to supply the sensor element 44 with electrical energy and to transmit the signal to a control unit (not shown). The leadframe 14 comprises at least two separate electrical conductors. A coupling capacitor, for example, is arranged between the two electrical conductors, which serves for the capacitive coupling of the two electrical conductors. The leadframe extends from a side of the sensor adjacent to the base plane Gv and from the outside into the housing.

[0027] The electrical connection 16 is located on the leadframe 14. The leadframe 14 and the electrical connection 16 partially overlap. In this overlap area, the leadframe 14 and the electrical connection 16 are welded or crimped together.

[0028] The electrical connector 16 is divided into three sections. The first section 38 overlaps the leadframe 14 in the overlap area and extends further into the housing 18. The second section 40 extends from the first section 38 and is bent at a 90° angle to the first section. The second section 40 extends perpendicularly towards the center of the housing. Between the first section 38 and the second section 40, the electrical connector 16 is bent at a radius. The third section 42 is arranged at the end of the second section 40 at an angle between 15° and 45° to the longitudinal axis of the second section 40. The third section 42 protrudes from the housing 18 and forms part of, or projects into, the connector receptacle 22. The electrical connector 16 serves to transmit electrical energy and data from the sensor 12 to the connector receptacle 22.

[0029] The connector receptacle 22 is located on the outer surface 26 of the housing 18. The connector receptacle 22 is part of the housing 18. The connector receptacle 22 serves to receive a connector (not shown) to which an electrical conductor for supplying power to and transmitting data from the sensor 12 is attached. To hold the connector in the connector receptacle 22, at least two locking elements 28 are provided on the connector receptacle 22, into which locking elements arranged on the connector engage.

[0030] Starting from the inside 24 of the housing 18, it extends in a radius which is larger than the defined distance R S is a structure 30 extending from the inner side 24. This structure 30 extends over the entire circumference of the housing 18. The structure 30 and the base body of the sensor device together form a receiving space 32, which receives the (not shown) rotating body with the encoder elements arranged on it.

[0031] The structure 30 has an end piece. The end piece of the structure 30 is the region furthest from the inner surface 24. The end piece of the structure 30 has a fixing element 34 on its outer surface. The fixing element 34 extends over the entire circumference of the structure 30. For improved retention on the housing 18, the fixing element 34 is partially connected to the structure 30. The fixing element 34 allows the housing 18 to be positively and force-fitted onto a corresponding counterpart (not shown here), for example, the outer ring of a bearing in which the rotating body is mounted.

[0032] The sensor element 44 is designed to detect a change in a magnetic field. Permanent magnets (not shown) pass by the end face of the sensor 12, i.e., the side opposite the leadframe 14 protruding from the housing. These permanent magnets are arranged on the rotating body (not shown). The permanent magnets are positioned at fixed intervals around the circumference of the rotating body, so that the change in the magnetic field also occurs at fixed intervals. The velocity can be determined from the change in the magnetic field over time and the known distances between the permanent magnets.

[0033] In Fig. Figure 2 shows that the structure 30 of the housing 18 extends in the complete circumferential direction of the housing 18. The fixing means 34, which is arranged at the end of the structure 30, also extends in the complete circumferential direction like the structure 30.

[0034] The sensor 12 is surrounded by a pocket 36. The pocket 36 at least partially surrounds the sensor 12, so that a recess 46, which is part of the sensor housing of the sensor 12, is visible. The pocket 36 containing the sensor 12 extends from the inside 24 of the housing 18 into the receiving space 32. This recess 46 serves to fix the sensor during the manufacturing process of the sensor device by engaging a suitable tool in the recess 46 and fixing the sensor 12 with another tool or tool part located on the side opposite the recess 46.

[0035] In Fig.Figure 3 shows the manufacturing process of the sensor device 10. In the first step, the sensor 12 is fixed by a tool. The tool comprises a tool core and a sliding core. The tool core engages in the previously described recess 46 of the sensor housing. On the side opposite the recess 46, there is a raised section on the sensor housing. The sliding core moves over this raised section, thereby fixing the sensor between the two tool parts.

[0036] The second step involves connecting the sensor 12 to the electrical connection 16. Here, the electrical connection is positioned on the leadframe 14 of the sensor 12, for example, using a gripping element. The leadframe 14 and the electrical connection 16 are then preferably welded together by ultrasonic welding. However, other welding methods are also conceivable. Alternatively, the leadframe 14 and the electrical connection 16 are crimped together, i.e., joined by plastic deformation.

[0037] During the connection of the leadframe 14 and the electrical connector 16, the electrical connector 16 has web elements between the individual electrical conductors of the leadframe 14. These web elements are removed after connection, for example by punching.

[0038] In the next step, the fixing element 34 is arranged around the sensor 12. This is done, for example, by the same gripping element that has attached the electrical connection 16 to the leadframe 14.

[0039] Once the fixing element 34 is in the position designated for the manufacturing process, the production process of the housing 18 begins. The position of the fixing element 34 can be determined and verified, for example, by a sensor. The housing 18 is produced by an injection molding process using a polymer or plastic.

[0040] In a final step, the finished sensor device 10 is ejected from the tool or removed by an operator. The process then begins again.

[0041] In another embodiment, the sensor 12 can be rotated by 180° on the axis parallel to the axis of rotation. Thus, the recess 46 is on the outward-facing side. This arrangement of the sensor 12 is related to the direction of rotation of the encoder element. Reference sign 10 Sensor device 12 Sensor 14 Leadframe 16 electrical connection 18 cases 20 Rotation axis 22 Connector arrangement 24 Inside 26 Outside 28 Resting materials 30 Structure 32 Recording room 34 Fixatives 36 bags 38 First Section 40 Second Section 42 Third Section 44 Sensor element 46 In-depth study Rs Defined Distance Gv basic plane of the sensor device

Claims

[1] Sensor device (10) for detecting a rotational speed, wherein the sensor device (10) comprises a sensor (12) for detecting the rotational speed of a rotating body about an axis of rotation (20) and a housing (18), wherein the housing (18) extends with a base body in a ground plane (Gv), wherein the housing has an inner side (24) and an opposite outer side (26), wherein the sensor (12) has a leadframe (14), a sensor element (44) arranged on the leadframe (14) and an electrical connection (16) arranged thereon for supplying power to the sensor, wherein the leadframe (14) is at a defined distance (R) S ) is arranged from the axis of rotation (20) on the inside (24) of the housing (18), wherein the leadframe (14) extends parallel to the axis of rotation (20) from a side of the sensor (12) adjacent to the ground plane (Gv) away from the outside (26), wherein the electrical connection (16) is divided into a first section (38), a second section (40) and a third section (42), wherein the first section (38) extends from the leadframe (14) into the housing (18), wherein the second section (40) extends at an angle of 90° from the first section towards the axis of rotation (20), wherein the third section (42) extends in a direction at an angle between 0 and 45° from the second section. [2] Sensor device according to claim 1, characterized by , that the sensor (12) has a sensor housing. [3] Sensor device according to claim 2, characterized by , that the sensor housing has a recess (46) on a first side, wherein the first side is a sensor housing base surface. [4] Sensor device according to claim 3, characterized bythat the sensor housing has a protrusion on a second side, with the second side opposite the first side. [5] Sensor device according to one of the preceding claims, characterized by , that the leadframe (14) and the first section (38) of the electrical connection (16) are welded or crimped together. [6] Sensor device according to one of the preceding claims, characterized by , that the sensor (12) forms a connector receptacle (22) on the outside (26) of the housing (18), into which the third section (42) protrudes. [7] Sensor device according to one of the preceding claims, characterized by , that the housing (18) provides at least one pocket (36) for the sensor, wherein the pocket (36) at least partially surrounds the sensor housing. [8] Sensor device according to one of the preceding claims, characterized by, that the housing (18) is pot-shaped, wherein a structure (30) extends from the inside (24) of the housing (18) and forms a receiving space (32), wherein the sensor (12) is arranged on the inside (24) of the housing (18). [9] Sensor device according to claim 8, characterized by , that a fixative (34) is enclosed at one edge of the recording space (32). [10] Method for manufacturing a sensor device according to one of the preceding claims, wherein the sensor device comprises a sensor, a housing, a leadframe and an electrical connection, comprising the following steps: • Fixing the sensor with a tool • Connecting the leadframe to the electrical connection by welding or crimping • Inserting a fixing agent into the tool • Creating the housing that at least partially surrounds the sensor, the electrical connection, and the fixing agent.

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