LOAD MEASUREMENT DEVICE AND METHOD FOR DETERMINING LOAD

Abstract

The invention relates to a load measuring device including a deformable component configured to be deformed under a load to be measured and a sensor assembly attached to a first portion of the deformable component and to a method for determining load using such a sensor assembly. It is proposed that the sensor assembly includes at least one acceleration sensor configured to detect a change in an orientation of the first portion with regard to the direction of gravity and that the deformable component is formed as a seal configured to be in sliding contact with a component configured to rotate in relation to the seal.

Claims

1. A load measuring device including a deformable component configured to be deformed under a load to be measured and a sensor assembly attached to a first portion of the deformable component, wherein the sensor assembly includes at least one acceleration sensor configured to detect a change in an orientation of the first portion with regard to the direction of gravity, and wherein the deformable component is formed as a seal configured to be in sliding contact with a component configured to rotate in relation to the seal.

2. The load measuring device according to claim 1, wherein the seal has a profile with an inclined portion connecting a fixing portion of the seal supported by a metallic flange with a contact portion of the seal.

3. The load measuring device according to claim 1, wherein the component configured to rotate in relation to the seal is an inner ring of a bearing.

4. The load measuring device according to claim 1, wherein the component configured to rotate in relation to the seal is a rotating shaft.

5. The load measuring device according to claim 1, wherein the acceleration sensor is formed as a semiconductor based 3-axis acceleration sensor.

6. The load measuring device according to claim 1, wherein the sensor assembly includes at least two acceleration sensors attached to different portions of the component.

7. The load measuring device according 6, wherein the deformable component is a torque bar, wherein the two acceleration sensors are attached to opposite ends of the torque bar.

8. The load measuring device according to claim 1, further comprising a data processing device configured to calculate a load acting on the deformable component based on the signals obtained from the sensor assembly.

9. A method for determining a load acting on a deformable component, the method comprising the steps of: using signals of an acceleration sensor to determine the load, attaching the acceleration sensor is attached to a first portion of the component in order to detect a change in an orientation of the first portion with regard to the direction of gravity, wherein the deformable component is formed as a seal configured to be in sliding contact with a component configured to rotate in relation to the seal.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0014] FIG. 1 is a schematic illustration of a load measurement device related to the invention;

[0015] FIG. 2 is a schematic illustration of a load measurement device related to the invention including a torque bar; and

[0016] FIG. 3 is a schematic illustration of a bearing equipped with a load measurement device according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] FIG. 1 is a schematic illustration of a load measurement device related to the invention.

[0018] The load measuring device according to FIG. 1 includes a deformable component 10 formed as a bar configured to be deformed under a load L to be measured. The bar 10 is fixed to a support 17 on one of its ends, is oriented horizontally, i.e. perpendicular to the direction of gravity G, and is configured to support the load L on the other one of its ends.

[0019] A sensor assembly 12 including an acceleration sensor 14, more specifically a 3-axis acceleration sensor, is attached to a first portion close to a free end of the deformable component 10. The gyro sensor 14 is configured to detect a change in an orientation of said first portion with regard to the direction of gravity G.

[0020] In applications where an apparatus including the deformable component 10 may change its orientation with regard to the gravity direction G as a whole, such as in vehicles running up and down slopes, it may be necessary to calibrate the sensor signals. In this case, the sensor assembly 12 may be provided with at least two acceleration sensors 14a, 14b attached to different portions of said component. A data processing device 16 configured to evaluate the sensor signals and to calculate the load based thereon may determine the difference between the orientations of the acceleration sensors 14 in order to discount a rotation or displacement of the deformable component 10.

[0021] FIG. 2 illustrates a related device where the deformable component 10 is a torque bar. Two acceleration sensors 14a, 14b are attached to opposite ends of the torque bar 10 and measure a difference in the relative orientation of the acceleration sensors 14 as a consequence of a twisting of the torque bar 10.

[0022] FIG. 3 illustrates third embodiment of the invention wherein the deformable component 10 is formed as a bearing seal, preferably attached to an outer ring of a bearing. The seal 10 has a profile with an inclined portion 10c connecting a fixing portion 10a of the seal supported by a metallic flange with a contact portion 10b of the seal 10, wherein the contact portion 10b is in sliding contact with an inner ring 20 of the bearing. In further embodiments of the invention, the seal 10 might be in sliding contact with a rotating shaft 20 or the seal 10 might be attached to an inner ring of the bearing.

[0023] High radial loads acting on the bearing may lead to a deformation of the bearing rings and/or to a redistribution of the roller elements of the bearing such that the radial distance between the rings of the bearing in the main load direction depends on the radial load. The orientation of the inclined portion 10c of the sealing lip in space will therefore change in response to radial or axial loads acting on the bearing in an amount sufficient to be detected.

[0024] Though only illustrated in the embodiment of FIG. 3, the load measuring device may include a data processing device 16 configured to calculate a load acting on the deformable component 10 based on the signals obtained from the sensor assembly 12. The data processing device 16 may use e.g. a characteristic determined using test loads and stored in a memory device.

[0025] The above embodiment of the invention relates to a method for determining a load acting on a deformable component 10 using a load measurement device as described above. In the method according to the invention, the load is determined using signals of one acceleration sensor 14 or multiple acceleration sensors 14, wherein said at least one acceleration sensor 14 is attached to a first portion of said component in order to detect a change in an orientation of said first portion with regard to the direction of gravity G.