DE102021112952A1 - Sensor bearing with shielding ring - Google Patents

Abstract

Combined sensor and storage devices are used to carry out the "storage" and "measurement" functions in traction machines in an installation-friendly and space-optimized manner. Thanks to the combined sensor and storage devices, they can be assembled in one operation. In addition, these are often more compact than the arrangement of a measuring device next to a bearing device. A sensor bearing 1 for the angle detection of a shaft in a traction machine is proposed, with a fixing sleeve 3, with a roller bearing device 4, with the roller bearing device 4 having an inner ring 5 and a Outer ring 6 and a plurality of rolling elements 7 rolling between inner ring 5 and outer ring 6, with outer ring 6 being connected to fixing sleeve 3 and inner ring 5 being connectable to the shaft, with rolling bearing device 4 being open to media and/or oil-lubricated, with a Sensor rotor 12, with the sensor rotor 12 being non-rotatably connected to the inner ring 5, with an inductive sensor system 8 for detecting the angle of the sensor rotor 12, with the sensor system 8 being arranged in the fixing sleeve 3 and with the sensor rotor 12 being arranged between the sensor system 8 and the roller bearing device 4 is, with a metallic shielding ring 19 to the A Shielding of the sensor system 8 from interference, with the shielding ring 19 being arranged between the rolling bodies 7 and the sensor rotor 12 in order to shield the sensor system 8 from faults caused by the rolling bodies 7 .

Description

The invention relates to a sensor bearing with a shielding ring having the features of the preamble of claim 1.

Combined sensor and storage devices are used to carry out the "storage" and "measurement" functions in traction machines in an assembly-friendly and space-optimized manner. Thanks to the combined sensor and storage devices, they can be assembled in one operation. In addition, these are often more compact than the arrangement of a measuring device next to a storage device.

The pamphlet WO 2019/063095 A1 , which is believed to be the closest prior art, discloses such a sensor and bearing assembly, wherein the sensor portion is axially juxtaposed with the bearing assembly. The bearing device is provided with a seal on both sides, so that the rolling body space is closed. The description shows that the sensor and bearing device can have an electromagnetic element, the electromagnetic element being designed as a ring disk, with the ring disk protecting the sensor and bearing device from electromagnetic interference from the environment.

It is the object of the invention to propose a sensor bearing which has an improved measurement performance. This problem is solved by a sensor bearing with the features of claim 1. Preferred or advantageous embodiments of the invention result from the dependent claims, the following description and the attached figures.

The subject matter of the invention is a sensor bearing, in particular a ring-shaped one, which is suitable and/or designed for detecting the angle of a shaft in a traction machine. The sensor bearing functions in particular as a resolver, in particular as an angle resolver. The sensor bearing is particularly preferably designed to be able to carry out an absolute angle detection of a rotation angle of the shaft. In less preferred embodiments, the sensor bearing is configured to perform an incremental angle detection of an angle of rotation of the shaft. In particular, a speed can be derived from the angle detection.

The sensor bearing is suitable and/or designed for a traction machine of a vehicle. In particular, the traction machine is an electric drive from the vehicle. The traction machine is particularly preferably used to provide a main torque for the vehicle. In principle, the shaft can be any shaft in the drive train of the traction machine between the electric motor and the vehicle wheel. However, the shaft is particularly preferably designed as a rotor shaft. In particular, the shaft and/or the sensor bearing is/are arranged in a transmission chamber of the traction machine that is in particular lubricated with transmission oil. An optional subject matter of the invention is formed by a traction machine and/or a vehicle with the traction machine and with the sensor bearing.

The sensor bearing has a fixing sleeve. The fixing sleeve is designed in particular as a metal component. The basic shape of the fixing sleeve is ring-shaped and/or hollow-cylindrical. The fixing sleeve is particularly preferably realized in one piece. For example, the fixing sleeve is implemented as a shaped sheet metal part. On the one hand, the fixing sleeve has the function of enclosing components of the sensor bearing and, on the other hand, of creating a coupling with a roller bearing device.

The sensor bearing has a roller bearing device. The rolling bearing device has an inner ring and an outer ring as well as a plurality of rolling elements rolling between the inner ring and the outer ring. The rolling bodies are preferably implemented as balls. The outer ring is in particular non-rotatably connected to the fixing sleeve. The outer ring and the fixing sleeve preferably have the same outside diameter. Particularly preferably, the outer ring is or can be arranged in the traction machine in a stationary and/or non-rotatable manner. The inner ring, on the other hand, can be connected, in particular connected, to the shaft. During operation, the inner ring thus rotates together with the shaft.

It is provided that the roller bearing device is open to media, in particular open to transmission oil, and/or is oil-lubricated. For example, the rolling body space of the rolling bearing device is designed without a seal on at least one side and/or is open for lubrication with gear oil.

The sensor bearing has an inductive sensor system for detecting the angle of the shaft and/or the inner ring. After the shaft and inner ring rotate together, this speed is the same. The sensor system comprises a circuit board, with at least one sensor being arranged on the circuit board. The circuit board preferably has the shape of a circular ring. The sensor is formed, for example, by a transmitting and/or receiving antenna structure and a digital data processing device such as an ASIC.

The sensor bearing includes a sensor rotor, which is non-rotatably connected to the shaft and/or to the inner ring, preferably to the inner ring, with the sensor or the sensor system being able to measure information from the sensor rotor. The sensor rotor is arranged between the sensor system and the roller bearing device.

The sensor bearing has a metallic shielding ring to shield the sensors from interference. In particular, the shielding ring is designed to protect the sensor system from interference from the surroundings of the roller bearing device and/or the sensor bearing. The shielding ring extends in particular in a radial plane to the main axis of rotation of the sensor bearing. The shielding ring is preferably designed as a contoured sheet metal ring disk.

In the context of the invention, it is proposed that the shielding ring is arranged between the rolling bodies and the sensor rotor in order to shield the sensor system from interference from the rolling bodies.

While the known prior art discloses such a shielding ring for shielding interference from the environment of the sensor and bearing device, so that it is to be arranged according to the disclosure on the bearing on the side facing away from the sensor, it is proposed, deviating from this, that according to the invention the shielding ring is arranged axially between the rolling elements and the sensor rotor and thus protects the sensors from interference from the rolling elements. The invention is based on the consideration that not only the surroundings of the sensor bearing can lead to disturbances in the sensor system, but that the rolling elements in the rolling bearing device also represent a source of disturbance. In particular, when the rolling elements slip through in a sliding manner, this has the effect that the relative angular position between the sensor rotor and the rolling elements lined up next to one another is shifted. After the inductive sensor system measures the inductance or its quality by changing the position relative to a conductive and/or ferromagnetic part, a change in the relative angular position between the sensor rotor and the row of rolling elements leads to a change in the measurement signal. Due to the fact that the metallic shielding ring is arranged between the rolling elements and the sensor rotor, the interference caused by this can be effectively shielded. From one perspective this results in improved measurement performance. Another way of looking at it is that the axial distance between the sensor rotor and the rolling bodies can be reduced without the disturbances caused by the rolling bodies impairing the measuring accuracy, so that a space-optimized sensor bearing without a seal is proposed via the configuration according to the invention.

In a preferred development of the invention, the shielding ring closes off a rolling body space of the rolling bearing device. More precisely, it is preferred that the shielding ring covers an exit ring gap of the rolling body space radially on the outside and/or radially on the inside in an axial plan view. This ensures that the inductive detection of the rolling elements by the sensors is minimized. In particular, the shielding ring has the shape of a circular ring.

Structurally, it is preferred that the shielding ring is fixed to the outer ring. Since the outer ring is the stationary bearing partner in the application, the shielding ring does not have to be rotated as well, but can also remain stationary. The shielding ring is particularly preferably spaced apart from the inner ring by an annular gap and/or is arranged without contact. The annular gap is dimensioned in such a way that the rolling body space is covered by the shielding ring in an axial plan view, but the distance is preferably selected to be larger than, for example, in the case of an oil seal.

The sensor bearing can be implemented in a particularly simple manner if the sensor rotor is clamped and/or pressed onto the inner ring. For example, the sensor rotor has a sensor collar, with the sensor collar forming an axial sleeve section and with the sensor rotor being arranged on the inner circumference or on an outer circumference of the inner ring.

The axial distance between the shielding ring and the sensor rotor is preferably greater than the distance between the sensor rotor of the sensor system. This preferred embodiment takes into account that the sensors are intended to measure the sensor rotor, in particular the sensor markings, but the interference from the rolling bodies is to be minimized. Due to the fact that the sensor rotor is arranged eccentrically between the shielding ring and the sensor system in the direction of the sensor system, the metrological detection of the sensor rotor by the sensor system is improved on the one hand and the interference from the rolling elements is reduced on the other.

In one possible embodiment of the invention, the shielding ring is designed as a plastic ring with embedded metal fabric or embedded metal particles. In an alternative embodiment of the invention, the shielding ring is designed as a shielding plate. The shielding ring is thus implemented as a shaped sheet metal part, which on the one hand can be produced inexpensively and on the other hand can be fastened mechanically to the outer ring in a simple and known manner. However, it is preferable that no oil sealing function is implemented in the configurations.

In one possible implementation of the invention, it is provided that the sensor rotor has cutouts, with the sensor system being designed to inductively detect the cutouts as sensor markings. The cutouts are particularly preferably implemented as edge cutouts.

In a preferred development of the invention, the sensor markings and/or a measuring area of the sensor system are arranged in the same radial area or at least radially overlapping as the rolling element space and/or the rolling elements. In this development, the largest possible diameter is selected for the metrological detection of the sensor markings, so that the measurement resolution is particularly high due to the diameter, but without increasing the radial size of the sensor bearing. In particular, the outer ring also defines a maximum diameter for the sensors.

• 1 eine schematische dreidimensionale Längsschnittdarstellung von einem Sensorlager als ein Ausführungsbeispiel der Erfindung;
• 2 eine schematische dreidimensionale Darstellung von dem Sensorlager in der 1, wobei einige Komponenten zeichnerisch unterdrückt sind;
• 3 a, b jeweils in einer schematischen, dreidimensionalen Darstellung zwei weitere Ausführungsbeispiele des Sensorlagers.

Further features, advantages and effects of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. These show:

• 1 a schematic three-dimensional longitudinal sectional view of a sensor bearing as an embodiment of the invention;
• 2 a schematic three-dimensional representation of the sensor bearing in FIG 1 , with some components graphically suppressed;
• 3a, b each in a schematic, three-dimensional representation of two further exemplary embodiments of the sensor bearing.

the 1 shows a schematic three-dimensional representation of a sensor bearing 1 as an embodiment of the invention. It is used to capture the angle of a shaft in an automotive traction machine. The sensor bearing 1 is designed as a self-retaining assembly. The shaft can be passed through the sensor bearing 1 through a central passage opening 2 . The shaft and/or the sensor bearing 1 defines a main axis of rotation H.

The sensor bearing 1 has a fixing sleeve 3, the fixing sleeve 3 being designed as a shaped sheet metal part. The sensor bearing 1 has a roller bearing device 4, in particular a radial roller bearing device, with an inner ring 5 and an outer ring 6 as well as a plurality of rolling elements 7 rolling between the inner ring 5 and the outer ring 6, designed as balls. The inner ring 5 can be connected to the shaft in a torque-proof manner. The outer ring 6 is connected to the fixing sleeve 3 to form the self-retaining assembly. The fixing sleeve 3 is pushed onto the outer ring 6. For this purpose, it has an encircling receiving shoulder 9 . For example, the fixing sleeve 3 can be arranged in a clamped and/or pressed manner on the outer ring 6 .

The sensor bearing 1 has a sensor system 8 for detecting the angle of the shaft and/or the inner ring 5, the sensor system 8 being designed as an inductive sensor system. The sensor system 8 is in the form of a ring and is arranged in the fixing sleeve 3 . The fixing sleeve 3 has a hollow cylinder section 10 and a cover section 11 . The hollow cylinder section 10 is arranged coaxially to the main axis of rotation H and sits at least in sections on the outer ring 6. The cover section 11 is in a radial plane to the main axis of rotation H, with the sensor system 8 in the axial direction on the hollow cylinder section 10 and in the axial direction on the cover section 11 applied.

The sensor bearing has a sensor rotor 12 , the sensor rotor 12 having a collar section 13 and a disk section 14 . The collar section 13 is in the form of a hollow cylinder and runs coaxially to the main axis of rotation H. The outer circumference of the collar section 13 is pushed, in particular pressed, onto an axial section 15 of the inner ring 5, so that the sensor rotor 12 is connected to the inner ring 5 in a rotationally fixed manner. The disc section 14 runs in a radial plane to the main axis of rotation H and has sensor markings 16, which are implemented as edge recesses, as can be seen from FIG 2 results. The sensor markings 16 are in the same or at least overlapping diameter range as the rolling bodies 7. A measuring range of the sensor system 8 is therefore also in the same or at least overlapping diameter range as the rolling bodies 7.

As can be seen from the 3a, b results, the sensor system 8 has a circuit board 17 which is designed in the form of a closed ring. The circuit board 17 is arranged adjacent to the sensor rotor 12 . The circuit board 17 has at least one sensor 18, wherein the sensor 18 can have a transmitting and/or receiving antenna structure and an electrical data processing device, such as an ASIC. During operation, the sensor 18 scans the sensor rotor 12, with the sensor 15 detecting an angular position of the sensor rotor 12 on the basis of the sensor markings 16 and thus being able to carry out an angle detection for the inner ring 5 and/or for the shaft. The sensors 8 in the 1 and 2 can be the same as the sensors in the 3a , b be constructed.

However, it was found that the rolling bodies 7 represent a disturbance variable for the measurement of the angular position of the sensor rotor 12 by the sensor system 8 . The rolling bodies 7 are also made of metal and are therefore also detected by the sensors 8 . Particularly in the event that the rolling elements 7 do not roll but slide, a relative angular position between the sensor rotor 12 and the rolling elements 7 arranged in a row shifts, with this relative shift forming a disturbance variable for the sensor system 8 .

In order to shield the sensor system 8 from the aforementioned interference from the rolling bodies 7, the sensor bearing 1 has a metallic shielding ring 19, with the shielding ring 19 taking the form of a metallic seal. The shielding ring 19 is designed as a shaped sheet metal part and is fixed to the outer ring 6 . For this purpose, the outer ring 6 has a sealing shoulder 20 , the outer circumference of the shielding ring 19 being pressed into the sealing shoulder 20 .

The inner circumference of the shielding ring 19 is arranged without contact with the inner ring 5, separated by an annular gap. In order to increase the mechanical rigidity, the shielding ring 19 can have a depression between the inner circumference and the outer circumference in the longitudinal section shown.

If one considers the shielding ring 19 and the roller bearing device 4 in an axial top view, the shielding ring 19 overlaps with the outer ring 6. Furthermore, the shielding ring 19 overlaps with the inner ring 5. The roller bearing device 4 forms a rolling body space, with this space having an exit ring gap, in particular a minimal exit ring gap having. Provision is made for the shielding ring 19 to have a larger outside diameter than the exit annular gap and a smaller inside diameter than the exit annular gap. This ensures that, starting from the sensor system 8 with the measuring direction in the direction of the rolling elements 7, these are safely shielded by the shielding ring. Due to the metallic shielding ring 19, the rolling bodies 7 are virtually hidden or covered for the sensor system 8 and thus represent no or at least only reduced interference variables.

The roller bearing device 4 also has a cage 21 for guiding the rolling bodies 7, the cage 21 having a circumferential side ring 22, and on the other side the cage 21 is designed without a side ring. The side ring 22 is arranged on the side of the rolling elements 7 facing the sensors 8 and forms a further shielding of the rolling elements from the sensors 8.

The roller bearing device 4 is otherwise designed without seals. In particular, the rolling body space of the rolling bearing device 4 is open to the outside. This is necessary so that the roller bearing device 4 can be adequately lubricated by gear oil.

the 2 shows a schematic, three-dimensional representation of the sensor bearing 1, but without the fixing sleeve 3 and the sensor system 8. The representation shows in particular the sensor markings 16, which are designed as edge recesses, the sensor markings 16 being arranged overlapping with the rolling elements 7 in an axial top view are. With the positioning of the sensor markings 16 in the same diameter range as the rolling bodies 7, a maximum diameter for the angle detection via the sensor rotor 12 and thus a maximum angular resolution is implemented.

the 3a, b each show a modified exemplary embodiment of the sensor bearing 1. The circuit board 17 with the sensor 18 can be better seen from both illustrations, the circuit board 17 having the shape of a ring. In contrast to the exemplary embodiment in the preceding figures, the sensor rotor 12 is fixed on the inner circumference of the inner ring 5 via the collar section 13, with the latter having a corresponding receiving shoulder 9 on the inner circumference.

In the embodiment in the 3 a the sensor system 8 is embedded in a duroplastic jacket 23, with the duroplastic jacket 23 being fixed in the fixing sleeve 3. In the embodiment in the 3 b the sensor bearing 1 has a sensor carrier 24 , the sensor carrier 24 being injected into the fixing sleeve 3 . The sensor carrier 24 is closed with a cover 25 that is welded on, with an annular receiving space for receiving the sensor system 8 being formed between the sensor carrier 24 and the cover 25 . Both sensor bearings 1 each have such a shielding ring 19, which is arranged at the same position as in the previous exemplary embodiment and which assumes the same function.

In all three exemplary embodiments it can be seen that a distance between the shielding ring 19 and the sensor rotor 12 is greater than the distance between the sensor rotor 12 and the sensor system 8. This commonality again underlines the idea of designing the sensor bearing 1 in such a way that the detection of the sensor rotor 12, in particular the sensor markings 16, takes place as precisely as possible and the shielding tion of interference from the rolling elements 7 is also increased by a greater distance between the sensor rotor 12 and the shielding ring 19.

Reference List

1

sensor bearing

2

passage opening

3

fixing sleeve

4

roller bearing device

5

inner ring

6

outer ring

7

rolling elements

8th

sensors

9

recording shoulder

10

hollow cylinder section

11

cover section

12

sensor rotor

13

collar section

14

slice section

15

axial section

16

sensor markings

17

circuit board

18

sensor

19

shielding ring

20

sealing shoulder

21

Cage

22

side ring

23

thermoset jacket

24

sensor carrier

25

lid

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2019/063095 A1 [0003]

Claims (10)

Sensor bearing (1) for detecting the angle of a shaft in a traction machine, with a fixing sleeve (3), with a roller bearing device (4), the roller bearing device (4) having an inner ring (5) and an outer ring (6) and a plurality between the inner ring (5) and outer ring (6) has rolling rolling elements (7), the outer ring (6) being connected to the fixing sleeve (3) and the inner ring (5) being able to be connected to the shaft, the rolling bearing device (4) being open to media and /or is lubricated with oil, with a sensor rotor (12), the sensor rotor (12) being non-rotatably connected to the inner ring (5), with an inductive sensor system (8) for detecting the angle of the sensor rotor (12), the sensor system (8) being in of the fixing sleeve (3) and with the sensor rotor (12) being arranged between the sensor system (8) and the roller bearing device (4), with a metallic shielding ring (19) for shielding the sensor system (8) from interference, characterized in that the shield ing (19) between the rolling elements (7) and the sensor rotor (12) is arranged in order to shield the sensor system (8) from interference from the rolling elements (7). Sensor bearing (1) after claim 1 , characterized in that the shielding ring (19) closes off a rolling body space of the rolling bearing device (4). Sensor bearing (1) after claim 1 or 2 , characterized in that the shielding ring (19) covers an exit ring gap of the rolling body space radially on the outside and/or radially on the inside in an axial plan view. Sensor bearing (1) according to one of the preceding claims, characterized in that the shielding ring (19) is fixed to the outer ring (6) and is spaced apart from the inner ring (5) by an annular gap and/or is arranged without contact. Sensor bearing (1) according to one of the preceding claims, characterized in that the sensor rotor (12) is clamped and/or pressed onto the inner ring (5). Sensor bearing (1) according to one of the preceding claims, characterized in that the distance between the shielding ring (19) and the sensor rotor (12) is greater than the distance between the sensor rotor (12) and the sensor system (8). Sensor bearing (1) according to one of the preceding claims, characterized in that the shielding ring (19) is designed as a shielding plate. Sensor bearing (1) according to one of the preceding Claims 1 until 6 , characterized in that the shielding ring (19) is designed as a plastic ring with embedded metal fabric or embedded metal particles. Sensor bearing (1) according to one of the preceding claims, characterized in that the sensor rotor (12) has sensor markings (16) designed as recesses, the sensor system (8) being designed to detect the recesses inductively. Sensor bearing according to one of the preceding claims, characterized in that the sensor markings (16) and/or a measuring area of the sensor system (8) are arranged in the same radial area or at least radially overlapping as the rolling body space and/or the rolling bodies (7).

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