The present disclosure relates to an encoder for a wheel bearing, in particular for a rolling ball bearing. Furthermore, the disclosure relates to a wheel bearing with an encoder of this type.
EP 0 892 185 A2, for example, shows a seal with integrated encoder mounted between a fixed support and a rotating support of a rolling bearing or a bearing. The seal has a mobile frame with a disc. The magnetic encoding element is supported by the disc and formed by an elastomer loaded with magnetic particles that covers the outside of the disc. Furthermore, the magnetic encoding element carries a radial outer sealing lip attached to the disc and resting on the rotating support, and the disc is fixedly attached to a cylindrical support surface placed on the mobile support. The magnetic encoding element also carries an axi-radial lip that is in contact with a tapered support surface of the fixed support. The disc includes first and second walls axially displaced outwardly relative to the first wall, and the second wall is contiguous with the cylindrical support surface.
The present disclosure provides an encoder for a wheel bearing of a vehicle which is simple to manufacture and dimensionally stable. Example embodiments result from the following description and the attached figures.
An encoder for a wheel bearing includes a carrier plate ring having a radially running first leg and an axially running second leg. The axially running second leg of the carrier plate ring is arranged on an outer ring or on an inner ring of the wheel bearing. The carrier plate ring is at least partly surrounded by a magnetic encoding ring and has, on the radially running first leg, cut-outs distributed over the circumference. The first leg has a fold for forming a folded portion, and the folded portion of the first leg at least partly covers the cut-outs. The encoding ring has unipolar magnetization and at least partly contacts the cut-outs. In other words, the carrier plate ring is at least partially encased or overmolded with the material of the magnetic encoding ring. The encoding ring may be bonded to the carrier plate ring by means of a chemical bonding system, for example by means of vulcanization. Thus, the encoding ring is at least partially materially connected to the carrier plate ring with a material bond.
In accordance with an exemplary embodiment, the carrier plate ring is substantially L-shaped in cross-section and is formed from a metal, having a first leg and a second leg. The first leg runs substantially radially and the second leg runs substantially axially. Further, the radially oriented first leg is designed to be folded so that a folded portion is integrally formed therewith. In other words, the first leg is folded or has a fold at an application-dependent radial position, so that the radial end of the first leg or the folded portion points in the direction of the axially aligned second leg after a forming or folding operation. Consequently, the first leg and the folded portion of the first leg are axially adjacent to one another and are integrally connected via the fold. In other words, the radially running first leg and the folded portion are arranged substantially parallel to one another. The first and second legs are further arranged relative to one another in such a manner that a substantially right angle is created between the legs. The carrier plate ring may be ferromagnetic.
The carrier plate ring is pressed onto the respective rotatable ring in the wheel bearing, which may be the inner ring or the outer ring of the wheel bearing depending on the application, or arranged in a stationary manner, meaning axially fixed and non-rotatable, using an alternative suitable method. In contrast, in the example of the L-shaped carrier plate ring, the radially running first leg extends spatially between the inner and outer rings in the radial direction, and the encoding ring is substantially connected to the first leg and acts together with a sensor device.
The sensor device can include one or more sensor elements, such as a speed sensor, and the sensor elements can be based on different physical principles of operation.
The term “unipolar magnetized encoder” refers to an encoder whose magnetized material has only a single polarity. Depending on the spatial direction of the measured magnetic flux density, a polarity change takes place. If magnetization is measured in the x-direction, i.e., in the circumferential direction of the carrier plate ring, the measurement signal is symmetrical about the 0-point. In other words, there is a 0-point symmetrical course of a magnetic flux density component so that a polarity change occurs. However, if magnetization is measured in the z-direction, i.e., perpendicular to the radially running first leg or to the encoding ring surface, the encoding ring exhibits a single magnetization applied in only one direction over the entire circumference, which varies in intensity due to the changing material thickness of the encoding ring caused by the cut-outs.
To generate the magnetization of the encoding ring, a magnetization tool or magnetization head is used which has, for example, a cylindrical base and generates a unipolar magnetization on the encoding ring. Such a magnetization tool is comparatively simple to design and manufacture, compared to magnetization tools intended for the production of multi-pole encoders. This makes it possible to use a single magnetization tool regardless of the size of the encoder or the number of increments. Elastomers and thermoplastics enriched with appropriate magnetic filler, e.g., strontium ferrite SrFe, are suitable materials for the encoding ring.
The cut-outs formed on the radial first leg can be distributed evenly or unevenly over the entire circumference of the first leg, depending on the requirements. The cut-outs are thus formed as openings or windows in which the encoding ring at least partially engages. The cut-outs may be completely filled or closed by the material of the encoding ring. Thus, several cut-outs are arranged circumferentially distributed on the radial first leg, and the encoding ring is formed in a perforated manner.
The encoding ring may be arranged over the entire circumference of the carrier plate ring. Depending on the application, it is also conceivable to interrupt the encoding ring and thus arrange it in sections around the circumference of the carrier plate ring. In addition, it is conceivable to further guide or arrange the material of the encoding ring up to the seat of the axially running leg of the carrier plate ring on the inner ring or on the outer ring in order to improve the static sealing effect on the press fit.
The cut-outs on the radial first leg may be produced by punching before the fold and thus the folded portion of the radially running first leg are created by forming. The folded portion of the radially running first leg may be configured to form a counter face for a sealing lip of a sealing element. In other words, the folded portion is configured in such a manner that, in operation, at least one sealing lip of a sealing element comes into contact with the folded portion in a sealing manner. For this purpose, the respective sealing lip is essentially axially aligned and nestles against the counter face of the folded portion. Consequently, the folded portion is arranged on a side of the radially running first leg facing the axially running second leg. In other words, the folded portion is arranged on a side of the radial first leg facing the sealing element and axially comes into contact with the radially running first leg. Consequently, the radially running first leg is arranged essentially parallel to the folded portion.
Due to the fact that the carrier plate ring of the encoder can be produced by punching and forming, the encoder can be manufactured simply and inexpensively without further machining or forming steps. In addition, the dimensional stability and sealing effect is not limited. Furthermore, the encoder requires less axial installation space. The first leg and/or the folded portion may be subjected to a surface treatment by forming in the region of the contact or sliding surface of the sealing element before or after forming the fold in order to reduce friction between the carrier plate ring of the encoder and the sealing element and to increase the sealing effect.
Accordingly, the radially running first leg and/or the folded portion is surface-treated at least in sections. The surface treatment may include a reduction of the surface roughness.
According to an exemplary embodiment, the fold is formed on the radially running first leg in the region of the cut-outs. By turning over or folding the radially running first leg in the region of the cut-outs, a tooth-like structure is initially formed on the outer circumference of the carrier plate ring, wherein the intertooth spaces are formed by the cut-outs and the teeth are formed by the radial first leg, the fold and the folded portion abutting the first leg. The radial position of the fold is selected such that the folded portion of the carrier plate ring at least partially covers the part of the cut-out on the radially running first leg. In other words, the fold always forms the radially outermost point of the carrier plate ring.
Alternatively, the fold formed on the radially running first leg is formed on a side of the cut-outs facing away from the axially running second leg. In other words, the radial position of the fold is selected such that the radial section of the carrier plate ring at least partially covers the cut-out present on the radial first leg. In other words, after forming the radial leg, part of the cut-out remains as a through opening, and the size of the opening depends on the radial position of the fold. This opening is at least partially filled by the material of the encoding ring after a manufacturing step of the encoding ring. In this case, the radially outer diameter of the carrier plate ring is larger than in the alternative case when the fold is formed on the radially running first leg in the region of the cut-outs.
The encoding ring may have an axially running leg. The axially running leg is integrally connected to the material of the encoding ring which at least partially engages in the cut-outs and is radially spaced apart from and substantially parallel to the axially running second leg of the carrier plate ring. In addition, the axially running leg of the encoding ring can be oriented in the same direction as the axially running second leg of the carrier plate ring so that the encoder has a substantially C-shaped structure. The axial leg of the encoding ring is formed in conjunction with the sealing element, e.g., to form a labyrinth chamber. A so-called pre-sealing labyrinth is thus formed, which increases the service life of the sealing element arranged in the wheel bearing.
An encoder according to a further embodiment includes a carrier plate ring having a radially running first leg and an axially running second leg. The axially running second leg of the carrier plate ring is arranged on an outer ring or on an inner ring of the wheel bearing, and the carrier plate ring is at least partly surrounded by a magnetic encoding ring. A window plate ring with cut-outs distributed over the circumference is fastened to the radially running first leg of the carrier plate ring, and the encoding ring has unipolar magnetization and at least partly comes into contact in the cut-outs of the window plate ring. In other words, the carrier plate ring as well as the window plate ring are at least partially encased or overmolded with the material of the magnetic encoding ring. The encoding ring may be bonded to the carrier plate ring and to the window plate ring by means of a chemical bonding system, for example by means of vulcanization. The encoding ring is thus at least partially materially connected to the carrier plate ring and the window plate ring with a material bond. Thus, the window plate ring is connected to the carrier plate ring in a stationary manner, meaning axially fixed and non-rotatable, via the material of the encoding ring, which engages at least partially in the cut-outs of the window plate ring.
One difference from the previous embodiments is that the carrier plate ring has at least one radially running first leg and one axially running second leg, and, in this case, a fold of the radial first leg as well as punching of the carrier plate ring can be omitted. However, a punched window plate ring is arranged in a non-rotatable manner on the radial leg, which receives the material of the encoding ring, which, according to the previous embodiments, also comes into contact with the carrier plate ring and is connected thereto. This further simplifies the manufacture of the carrier plate ring, as a fold is not required in this case.
The carrier plate ring may have an axially running third leg. The axially running third leg of the carrier plate ring is integrally connected to the first and second legs and is radially spaced apart, i.e. arranged substantially parallel to the axially running second leg of the carrier plate ring. In addition, the axially running third leg of the carrier plate ring can be oriented in the same direction as the axially running second leg of the carrier plate ring so that the carrier plate ring has a substantially C-shaped structure. The axially running third leg of the carrier plate ring is formed in conjunction with the sealing element, e.g., to form a labyrinth chamber. A so-called pre-sealing labyrinth is thus formed, which increases the service life of the sealing element arranged in the wheel bearing.
The window plate ring may be arranged on a side of the radial first leg facing away from the sealing element so that an uninterrupted sealing surface for the sealing lip of the sealing element is provided by the radial leg of the carrier plate ring and the window plate ring is thus located on the rear side of the radially running first leg.
A wheel bearing according to the present disclosure includes an encoder of one of the types described above. The encoder is arranged in a non-rotatable manner on either an outer peripheral surface of an outer ring or on an inner peripheral surface of an outer ring. It is conceivable that the encoding ring and/or the carrier plate ring at least partly comes into contact with an end face of the inner or outer ring and/or is at least partially received in a depression or recess of the respective component. Furthermore, such an encoder can also be provided for alternative bearing elements, and a displaceable or rotatable component on which the encoding ring is arranged can be displaced or rotated relative to a stationary fixed component. For example, it is conceivable to provide the encoder for a linear bearing.
The encoding ring can be magnetized before mounting on the inner or outer ring. Alternatively, due to the comparatively simple magnetizability of the encoding ring, it is also conceivable to carry out single-pole magnetization after mounting the encoder in the wheel bearing. In this case, no dirt can accumulate until the time of magnetization, which would negatively affect the magnetization. Overall, the unipolar magnetization of the encoding ring exerts a comparatively low attraction on ferromagnetic (dirt) particles or contaminants.
The above definitions and explanations of technical effects and embodiments of the respective encoder also apply mutatis mutandis to the wheel bearing.
The present disclosure is described below together with a description of three exemplary embodiments using the figures, wherein identical or similar elements are marked with the same reference numeral. In the figures:
According to
The carrier plate ring 4 has a first radially running leg 4a and a second axially running leg 4b. The axial second leg 4b is arranged on the inner ring 3b of the wheel bearing 1 in a non-rotatable and axially fixed manner. The radial first leg 4a extends in a radial direction towards the outer ring 3a and is folded at a fold 15 so that a folded portion 4d of the first leg 4a extends in the opposite radial direction towards the inner ring 3b and abuts axially against the radial first leg 4a. Consequently, the folded portion 4d is arranged parallel to the first leg 4a. In the present case, the folded portion 4d is arranged on a side of the radially running first leg 4a facing the axially running second leg 4b.
The carrier plate ring 4 has cut-outs 10 distributed around the circumference on the radially running first leg 4a, which result in a different design of the carrier plate ring 4 depending on the radial position of the fold 15. The fold 15 is made after punching the cut-outs 10. In the embodiments according to
The encoding ring 7 is formed over the entire circumference of the first leg 4a of the carrier plate ring 4. The encoding ring 7 is unipolarly magnetized before or after it is mounted in the wheel bearing 1 and at least partly comes into contact in the cut-outs 10 of the carrier plate ring 4. Consequently, the material of the encoding ring 7 at least partially fills the space of the cut-outs 10, and the encoding ring 7 is supported on the corresponding walls of the cut-outs 10.
According to
According to the first embodiment of the encoder 2 also shown in
Furthermore, the encoding ring 7 has an axially running leg 7a. The axially running leg 7a is integrally formed on the material of the encoding ring 7 received in the cut-outs 10 and is radially spaced apart from and substantially parallel to the axially running second leg 4b of the carrier plate ring 4. In addition, the axially running leg 7a of the encoding ring 7 is aligned in the same direction as the axially running second leg 4b of the carrier plate ring 4 so that the encoder 2 has a substantially C-shaped structure. A pre-sealing labyrinth is formed through the axial leg 7a of the encoding ring 7 in order to make it more difficult or delay the ingression of dirt and/or moisture to the sealing element 9 and thereby increase the service life of the sealing element 9, for example.
As already indicated,
The sealing element 9 as shown in
According to
In this case, the task of the axial leg 7a of the encoding ring 7 according to the second exemplary embodiment is taken over by the axially running third leg 4c, and a sealing lip, not shown here, can come into contact with the radially running first leg 4a in a sealing manner.
For all embodiments, it is also conceivable that the carrier plate ring 4 is arranged in a non-rotatable and axially fixed manner on the outer ring 3a shown in
Number | Date | Country | Kind |
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10 2019 134 246.5 | Dec 2019 | DE | national |
This application is the United States National Phase of PCT Appln. No. PCT/DE2020/100937 filed Nov. 3, 2020, which claims priority to German Application No. DE102019134246.5 filed Dec. 13, 2019, the entire disclosures of which are incorporated by reference herein.
Filing Document | Filing Date | Country | Kind |
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PCT/DE2020/100937 | 11/3/2020 | WO |