Hub unit

Abstract

A hub unit including an end cap for preloading and retaining a bearing unit on an axle. The end cap is provided with a sensor unit for detecting at least one of vibrations and temperature of the bearing unit.

Claims

1. A hub unit including: an end cap for preloading and retaining a bearing unit on an axle, wherein the end cap is provided with a sensor unit for detecting at least one of vibrations and temperature of the bearing unit, the sensor unit having an arched shape formed in a radial direction of the end cap, the sensor unit being located proximate an annular edge of the end cap.

2. The hub unit according to claim 1, the sensor unit further comprising a wireless transmitter for sending the data acquired by the sensor unit.

3. The hub unit according to claim 2, further comprising a cover plate having a through hole, wherein at least an antenna portion of the transmitter unit protrudes through the through hole over the cover plate.

4. The hub unit according to claim 1, the end cap further comprising a pocket accommodating the sensor unit, wherein the pocket is covered by at least one cover plate.

5. The hub unit according to claim 4, wherein the pocket is formed as an annular recess arranged concentrically with respect a rotation axis of the bearing unit.

6. The hub unit according to claim 1, the sensor unit further comprising an overall arc-shaped sealed housing and with a circuit board arranged within the housing.

7. The hub unit according to claim 1, the sensor unit further comprising at least one acoustic emission sensor.

8. The hub unit according to claim 1, the sensor unit further comprising at least one gyro sensor.

9. A controller suitable for reading out data acquired by a sensor unit of a hub unit, the hub unit comprising: an end cap for preloading and retaining a bearing unit on an axle, wherein the end cap is provided with a sensor unit for detecting at least one of vibrations and temperature of the bearing unit, the sensor unit having an arched shape formed in a radial direction of the end cap, the sensor unit being located proximate an annular edge of the end cap, wherein the controller is configured to generate at least one of a status information and warning signals based on the detection results obtained from the sensor unit.

10. A hub unit including: an end cap for preloading and retaining a bearing unit on an axle; and a circuit board including multiple circuit board segments, the multiple circuit board segments being pivotably connected to one another by a flexible element, wherein the end cap is provided with a sensor unit for detecting at least one of vibrations and temperature of the bearing unit.

11. The hub unit according to claim 10, a wiring side of at least one of the multiple parts of the circuit board is oriented in a direction essentially opposite to a direction in which at least one neighboring part of the circuit board is oriented.

12. The hub unit according to claim 10, the sensor unit further comprising a wireless transmitter for sending the data acquired by the sensor unit.

13. The hub unit according to claim 12, further comprising a cover plate having a through hole, wherein at least an antenna portion of the transmitter unit protrudes through the through hole over the cover plate.

14. The hub unit according to claim 10, the end cap further comprising a pocket accommodating the sensor unit, wherein the pocket is covered by at least one cover plate.

15. The hub unit according to claim 14, wherein the pocket is formed as an annular recess arranged concentrically with respect a rotation axis of the bearing unit.

16. The hub unit according to claim 10, the sensor unit further comprising an overall arc-shaped sealed housing and with the circuit board arranged within the housing.

17. The hub unit according to claim 10, the sensor unit further comprising at least one acoustic emission sensor.

18. The hub unit according to claim 10, the sensor unit further comprising at least one gyro sensor.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will now be described in more detail for explanatory, and in no sense limiting, purposes, with reference to the following figures, in which

(2) FIG. 1 is a schematic cross-sectional view of a hub unit with an end cap and a two-row taper roller bearing;

(3) FIG. 2 is a sectional view of the end cap of FIG. 1;

(4) FIG. 3 shows an end cap of a hub unit according to the invention in an assembled state;

(5) FIG. 4 shows the end cap of FIGS. 1 and 3 with a sensor unit and with one cover plate removed;

(6) FIG. 5 shows the sensor unit of the hub unit according to FIGS. 3 and 4 separated from the hub unit;

(7) FIG. 6 shows the sensor unit of FIG. 5 with its top cover part removed;

(8) FIG. 7 shows the sensor unit of FIGS. 5 and 6, wherein a supporting plate carrying the transmitter unit is removed;

(9) FIG. 8 shows the sensor assembly and the circuit boards of the sensor unit according to FIGS. 5-7 without a housing of the sensor unit; and

(10) FIG. 9 shows a sectional view of the sensor unit according to FIGS. 4-8.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(11) FIG. 1 shows a hub unit including an end cap 10 fixed with three bolts 12 on an axial end face of an axle 13 so as to preload and retain a bearing unit 11 with a split inner ring and an outer ring fitted onto the axle 13. The bearing unit 11 is a two-row taper roller bearing in O-configuration.

(12) As illustrated in FIG. 3, the end cap 10 comprises a solid metal base part 14 and three arc-shaped cover plates 16a-16c fixed with two screws 17 respectively onto an axially outer side of the base portion 14 so as to surround the central portion with the bolts 12.

(13) The metal base part 14 is illustrated in a cross-sectional view in FIG. 2. An outer side of the metal base part 14, which faces away from the bearing unit 11 in the assembled configuration is provided with an annular, groove-like recess or pocket 18, which is symmetric with respect to a central hole of the end cap 10 and its base part 14. The annular, groove-like recess or pocket 18 is delimited by a metal wall 19 of essentially constant thickness on the radially outer side and by a solid bulk body of the base part 14 on the radially inner side.

(14) As illustrated in FIGS. 3 and 4, the cover plates 16a-16c cover the annular, groove-like recess or pocket 18 which is machined into the base portion 14 around its entire circumference concentrically to the rotational symmetry axis of the base portion 14. The base portion 14 has a threefold rotational symmetry, wherein only the holes 12a (FIGS. 1 and 2) for the bolts 12 and for the screws for fixing the cover plate 16a-16c break the complete rotational symmetry. As a consequence, the base portion 14 is very robust and sufficiently strong to support the required axial loads while having the required elastic properties and being at the same time easily machinable.

(15) As illustrated in FIG. 4, the sensor unit 20 is arranged in the annular groove-like recess or pocket 18. The sensor unit 20 has a protruding antenna portion 22, which is part of a wireless transmitter 24 of the sensor unit 20 and the cover plate 16a covering the sensor unit 20 has a through-hole 26 (FIG. 3). In the assembled configuration as illustrated in FIG. 3, the antenna portion 22 is fitted through the through-hole 26 so as to protrude over the cover plate 16a.

(16) FIG. 5 illustrates a configuration wherein the sensor unit 20 has been taken out of the annular, groove-like recess or pocket 18. The sensor unit 20 has a connector 28 for connecting the sensor unit 20 to a power supply, e.g. batteries or accumulators provided in the recess under the cover plates 16b and 16c.

(17) A top plastic cover 30 of a housing 32 of the sensor unit 20 is made of a very robust plastic material such as PPS GF30. Rolled metal inserts 34 are fitted into holes at both ends of the housing 32. The inserts 34 receive the screws for fixing the cover plate 16a such that the sensor unit 20 is fixed with the same screws.

(18) The top cover 30 is fixed on the housing by two further screws and an O-ring seal is provided between the top cover 30 and the rest of the housing 32. The bottom part of the housing 32 is equally made of the same robust plastic material as the top cover 30.

(19) FIG. 6 illustrates a configuration where the top cover 30 is removed. A base plate 36 supports the transmitter unit 24 and three parts of 38a, 38b, 40 of a circuit board are fitted into pertinent mounting slots in the housing 32 so as to be arranged parallel to an axial direction of the end cap 10, which corresponds to a rotation axis of the bearing 11. The circuit board 40 in the middle of the sensor unit 20 is arranged such that its wiring side faces radially outwards, i.e. towards the convex side of the housing 32, whereas the circuit boards 38a, 38b are arranged in the essentially opposite direction, i.e. such that their wiring sides face towards the concave side of the housing 32. As shown in FIG. 8, the circuit board 40 and the circuit boards 38a, 38b are connected to one another with flexible elements 41a, 41b so as to be pivotable. The entire circuit board configuration can therefore be easily fitted into the curved interior of the housing 32 while allowing for sufficient mounting space for the circuit elements despite of the curved shape of the housing 32.

(20) FIG. 7 shows a configuration where the base plate 36 with the transmitter 24 is removed. A bottom surface of the housing 32 is provided with a through-hole 42 (FIG. 9) receiving the sensor base plate 44 which is forced downwards by springs (not illustrated) thrusting to the backside of the base plate 36. The sensor base plate 44 carries vibration sensor and/or acoustic emission (AE) sensor 48 and a temperature sensor 50.

(21) As illustrated in FIGS. 8 and 9, a gyro sensor 52 is mounted on the circuit board 40.

(22) The sensor base plate 44 is pressed to the bottom surface of the annular, groove-like recess or pocket 18 in the base portion 14 of the end cap 10, which is very close to the inner ring of the bearing such that the temperature and the vibrations of the inner ring can be measured in a very reliable way.

(23) Further, two extra crystals for the transmitter unit 24 are provided on the central circuit board 40.

(24) The signals obtained by the sensors 48-52 are processed in a processing unit 54 on the circuit board 40 and transmitted in a wireless way by the transmitter 24 of the sensor unit 20. The signals are received and processed by a control unit (not illustrated) in the train, which compares the measured values with threshold values, which may be a function of the outside temperature or other outside parameters, and generates status information and/or warning signals in relation to the bearing unit 11.