Description:TECHNICAL FIELD
[0001] The present invention generally relates to a bearing assembly. More particularly, the invention describes an inductive sensor assembly for the bearing.
BACKGROUND OF THE INVENTION
[0002] A bearing encoder detects the movement of the rotating shaft on which it is mounted in particular to detect the speed of the motor or the shaft, or the position or the direction of rotation of a motor. Measuring these latter parameters allows the motor to be controlled in position or speed.
[0003] The United States patent 11242894, discloses a bearing, with an inner ring, an outer ring rotatable relative to the inner ring, and an inductive sensor for detecting a measured variable corresponding to a rotation of the outer ring relative to the inner ring. The sensor described in the patent comprises a stator connected to one of the inner ring and the outer ring, and a rotor. A spacer is arranged between the stator and the inner ring or the outer ring to which the stator is connected, and wherein the spacer comprises a shoulder that creates a defined distance between the stator and the rotor of the inductive sensor. This type of inductive sensors has a lot of components causing difficulty in assembling the sensor as well as maintenance of the same.
[0004] Another patent application CN113933053A discloses a non-contact induction type triboelectric bearing sensor and a test method thereof, wherein the sensor has a rolling bearing, a stator unit and a rotor unit, a charge supplementing device is arranged at a groove of an end cover of the stator unit, a grid electrode consisting of two annular interdigital electrodes, and an adjusting ring that is used for adjusting the distance between the electrode and the rotor unit with a retainer connecting plate and a PTFE ring. The invention can realize the detection of the rotating speed and the slip rate of the rolling bearing. Further, the invention is described to have the advantages of wide measuring range, high measuring precision, long service life and the like. The measurement of the rotational parameter is not suitable for ultra-high-speed applications. In addition, maintaining the adjusting ring is very critical component and it makes the design complex with lot of elements for the sensor.
[0005] Therefore, there is a need for an inductive sensor assembly that can overcome the drawbacks discussed and that can provide simple sensor assembly to measure rotational parameter for ultra-high-speed applications.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide an inductive sensor assembly for a bearing. The inductive sensor assembly includes a target coupled to an adapter wherein the adapter is mechanically coupled to an inner ring of the bearing. The inductive sensor assembly also includes an enclosure for housing a copper coil and a printed circuit board, wherein the printed circuit board is configured to sense the change in inductive field corresponding to the rotational parameters, wherein the enclosure is coupled to an outer ring of the bearing and the enclosure is stationary relative to the inner ring and the target.
[0007] Another object of the present invention is to provide a bearing. The bearing includes an outer ring, an inner ring rotatable relative to the outer ring and an inductive sensor assembly for detecting a rotational parameter signal corresponding to a rotation of the inner ring relative to the outer ring. The inductive sensor assembly includes a target coupled to an adapter wherein the adapter is mechanically coupled to the inner ring. The sensor assembly includes an enclosure for housing a copper coil and a printer circuit board. The printed circuit board is configured to sense a change in an inductive field corresponding to the rotational parameter. The enclosure is coupled to the outer ring and the enclosure is stationary relative to the inner ring and the target.
[0008] These and other objects of the invention herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The embodiments of the invention are illustrated in the accompanying drawings, throughout which the reference letters indicate corresponding part in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0010] Figure 1 illustrates perspective exploded view of an inductive sensor assembly along with a bearing, in accordance with an embodiment of the invention.
[0011] Figure 2 illustrates cross sectional exploded view of an inductive sensor assembly for a bearing, in accordance with an embodiment of the invention.
[0012] Figure 3 illustrates a cross sectional view of an inductive sensor assembly for a bearing, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] While various embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.
[0014] In the specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:
[0015] The singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. “Substantially” means a range of values that is known in the art to refer to a range of values that are close to, but not necessarily equal to a certain value.
[0016] Other than in the examples or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as modified in all instances by the term “about.” In some aspects of the current disclosure, the terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the terms are defined to be within 10%, alternatively within 5%, alternatively within 1%, or alternatively within 0.5%.
[0017] As used herein, the term “substantially” and its variations are defined as being largely but not necessarily wholly what is specified as understood by one of ordinary skill in the art, and in one non-limiting aspect substantially refers to ranges within 10%, within 5%, within 1%, or within 0.5%.
[0018] As used herein, “combinations thereof” is inclusive of one or more of the recited elements, optionally together with a like element not recited, e.g., inclusive of a combination of one or more of the named components, optionally with one or more other components not specifically named that have essentially the same function. As used herein, the term “combination” is inclusive of blends, mixtures, alloys, reaction products, and the like.
[0019] The present invention discloses an inductive sensor assembly for a bearing. The inductive sensor assembly includes a target coupled to an adapter wherein the adapter is mechanically coupled to an inner ring of the bearing. The inductive sensor assembly also includes an enclosure for housing a copper coil and a printed circuit board, wherein the printed circuit board is configured to sense a change in an inductive field corresponding to the rotational parameters. The enclosure is coupled to an outer ring of the bearing and the enclosure is stationary relative to the inner ring and the target.
[0020] Figure 1 illustrate perspective exploded view of an inductive sensor assembly 100 along with a bearing, in accordance with an embodiment of the invention. The inductive sensor assembly 100 includes a target 102 coupled to an adapter 104 wherein the adapter 104 is mechanically coupled to an inner ring 106 of the bearing. The inductive sensor assembly includes an enclosure 108. The enclosure 108 is a housing for a copper coil (not shown in the figure) and a printed circuit board 110. The printed circuit board 110 is configured to sense a change in an inductive field corresponding to the rotational parameters. The enclosure 108 is coupled to an outer ring 112 of the bearing and the enclosure 108 is stationary relative to the inner ring 106 and the target 102. In an embodiment of the present invention, the copper coil is incorporated along with the printed circuit board 110.
[0021] In an embodiment of the present invention, the printed circuit board 110 is fixed to the enclosure 108 using epoxy.
[0022] According to an embodiment of the present invention, the enclosure 108 includes a radially stepped shoulder. In an embodiment of the present invention, the radially stepped shoulder includes inward stepped member 114a and outward stepped member 114b. According to an embodiment of the present invention, each of the plurality of inward stepped member 114a has a protruded member 116 to enable the coupling of the enclosure to the outer ring 112.
[0023] According to an embodiment of the present invention, the copper coil and the printed circuit board is space separated from the target.
[0024] In an embodiment of the present invention, the enclosure 108 maintains the copper coil and the printed circuit board 110 to be spaced apart from the target 102.
[0025] Figure 2 illustrates cross sectional exploded view of an inductive sensor assembly 200 for a bearing, in accordance with an embodiment of the invention. The inductive sensor assembly includes the enclosure 208, the printed circuit board 210, the target 202 and the adapter 204. In an example embodiment, the target 202 is coupled to the adapter and is fixed to the inner ring 206 of the bearing and the enclosure 208 along with the copper coil (not shown in the figure) and the printed circuit board 210 is coupled to the outer ring 222 of the bearing.
[0026] Figure 3 illustrates a cross sectional view of an inductive sensor assembly for a bearing, in accordance with an embodiment of the invention. The inductive sensor assembly 300 includes the target 302 and the adapter 304. In the given example embodiment, the target is coupled to the adapter and is fixed to the inner ring 306 of the bearing. The inductive sensor assembly 300 further includes the enclosure 308 fixed with the printed circuit board 310, wherein the enclosure 308 is coupled to the outer ring 322. According to an embodiment of the present invention, the bearing includes rolling elements 324 rolling interposed between the inner ring 306 and the outer ring 322.
[0027] According to an embodiment of the present invention, the adapter is configured in a shape so as to receive the target and also to couple the adapter to the inner ring of the bearing. In an embodiment of the present invention, the adapter is made a strong, heat-resistant, and wear-resistant material. In another embodiment of the present invention, the adapter is made of a polyamide 66 (PA66). In some embodiments of the present invention the adapter can be made of materials such as polyamide having at least20% glass fibre. In example embodiment the adapter is made of PA66 with 30% glass fibre at high temperature. In an embodiment of the present invention, the adapter is configured in ring structure with flanges, wherein the flanges help in coupling the adapter to the inner ring.
[0028] According to an embodiment of the present invention, the copper coil is a four-layer copper coil. The copper coil is placed inside the stationary enclosure with the printed circuit board. In an embodiment of the present invention, the four-layer copper coil includes a pair of transmitters and receivers. According to an embodiment of the present invention, the two transmitter provides the sine and cosine signal for measuring the rotational parameters.
[0029] According to an embodiment of the present invention, the target is made up of at least one of a metal or flame-retardant epoxy resin fiberglass laminate. According to an embodiment of the present invention, the target is made up of copper or polycarbonate.
[0030] According to an embodiment of the present invention, the inductive sensor assembly may be integrated with any bearings without any modification on bearing level. According to an embodiment of the present invention, enclosure is made up of plastic material. In yet another embodiment of the present invention, the inductive sensor assembly may be retrofitted with the bearing.
[0031] According to an embodiment, the present invention may be implemented for any rotating electrical machine having a motor and/or generator operating mode, such as for example a motor vehicle alternator in starter mode. The sensor bearing could in particular be associated with an electric vehicle motor used in an electric or hybrid vehicle, or Permanent Magnet Synchronous Motor or Brushless DC Motor.
[0032] According to an embodiment of the present invention, when the target is rotated the flux changes and due to the flux changes a change in voltage occurs on the stationary copper coil fixed to the enclosure enables measurement of the rotational parameters. The measured rotational parameters are used to control the motor. The flux change results in the output as sine wave and cosine wave signal. These two signals, when combined, provide information about both magnitude and direction of the measured parameter. In an embodiment of the present invention, the printed circuit board gives the output as Pulse Width Modulation wherein the pulse width of a square wave varies in proportion to the measured parameter. This may be a simpler and more compact format than analogue and sine/cosine waveforms.
[0033] According to an embodiment of the present invention, the inductive sensor assembly uses Serial Encapsulation of Time as communication protocol. It uses a single wire and encodes information such as sensor values, timestamps, and error flags within the pulse timing of the signal.
[0034] According to an embodiment of the present invention, a signal processing unit calculates the angular rotation from 0 degrees to 360 degrees and the corresponding voltage is given as feedback to the motor controller to control the motor speed and torque. For example, analogue voltage-based sine and cosine signals from the inductive sensor assembly is used to determine the position of the shaft and that in turn helps in driving the permanent magnet synchronous motor by controlling the torque and current of the motor.
[0035] According to an embodiment of the present invention, a phase shift of about 90 degree between the target and the copper coil results in output signals that exhibit a corresponding 90 degree phase shift relative to the target position, producing ratiometric sine and cosine signals. These signals can be transformed into an absolute position by employing an arctangent operation involving the sine voltage (Vsin) and cosine voltage (Vcos) values. The position (P) is determined as the arctangent of the ratio of Vsin to Vcos.
P=arctan(Vcos/Vsin)
[0036] This mathematical operation allows for the calculation of the absolute position based on the phase relationship between the sine and cosine components of the received signals. Thus, the need of indexing signal to determine the absolute position is resolved using the combination of sine and cosine waves.
[0037] According to an embodiment of the present invention, the inductive sensor assembly envisaged in the present invention may provide three waveforms such as sine wave and cosine wave, triangular type of wave form or analogue type of wave form. According to an embodiment of the present invention, the printed circuit board convert the input signal from the inductive sensor into readable output.
[0038] In an embodiment of the present invention, the bearing is one of a ball bearing or roller bearing.
[0039] According to an embodiment, the present invention discloses a bearing. The bearing includes an outer ring, an inner ring rotatable relative to the outer ring and an inductive sensor assembly for detecting a rotational parameter signals corresponding to a rotation of the inner ring relative to the outer ring. The inductive sensor assembly includes a target coupled to an adapter wherein the adapter is mechanically coupled to the inner ring and an enclosure for housing a copper coil and a printed circuit board, wherein the printed circuit board is configured to sense the change in inductive field corresponding to the rotational parameter, wherein the enclosure is coupled to the outer ring and the enclosure is stationary relative to the inner ring and the target.
ADVANTAGES
[0040] The technical advantages brought in by the present invention are as follows;
1. The inductive sensor assembly for the bearing unit is used in ultra-high speeds applications. Some examples of the applications are traction e-motors, electronic power steering, belt starter generator, park brake actuator and pumps.
2. The bearing unit in the invention has the advantage of being easily manufactured and does not need any specialized expertise.
3. The key features of the bearing unit are sine/cosine single ended or differential.
4. The inductive sensor is retrofitted to existing bearings.
5. This invention can solve the magnetic encoder manufacturing problem.
6. Avoids indexing signals.
7. The rotational parameters are determined from the sine and cosine voltages is more accurate and excellent for long-term usage than the inductive sensors which uses the indexing signal.
8. Digital calibration and configuration storage are non-volatile.
[0041] While considerable emphasis has been placed herein on the components and component parts of the various embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the embodiments without departing from the scope and spirit of the invention. These and other changes in the various embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
, Claims:We claim:
1. An inductive sensor assembly for a bearing, wherein the inductive sensor assembly comprises:
? a target (102) coupled to an adapter (104), wherein the adapter (104) is mechanically coupled to an inner ring (106) of the bearing;
? an enclosure (108) for housing a copper coil and a printed circuit board (110), wherein the printed circuit board (110) is configured to sense a change in an inductive field corresponding to the rotational parameters, wherein the enclosure (108) is coupled to an outer ring (112) of the bearing and the enclosure (108) is stationary relative to the inner ring (106) and the target (102).
2. The inductive sensor assembly as of claim 1, wherein the printed circuit board (110) is fixed to the enclosure (108) using epoxy.
3. The inductive sensor assembly as of claim 1, the copper coil and the printed circuit board (110) is space separated from the target (102).
4. The inductive sensor assembly as of claim 1, wherein the enclosure (108) comprises a radially stepped shoulder.
5. The inductive sensor assembly as of claim 4, wherein the radially stepped shoulder comprises plurality of inward stepped members and a plurality of outward stepped members wherein each of the plurality of inward stepped member comprises a protruded member to enable the coupling of the enclosure to the outer ring.
6. The inductive sensor assembly as of claim 1, wherein the copper coil is a four-layer inductive coil.
7. The inductive sensor assembly as of claim 1, wherein the target (102) is made up of at least one of a metal or flame-retardant epoxy resin fiberglass laminate.
8. The inductive sensor assembly as of claim 1, wherein the printed circuit board (110) is configured to convert the input to readable output.
9. A bearing, comprising:
? an outer ring;
? an inner ring rotatable relative to the outer ring;
? an inductive sensor assembly for detecting a rotational parameter signal corresponding to a rotation of the inner ring relative to the outer ring, the inductive sensor assembly comprises:
? a target coupled to an adapter wherein the adapter is mechanically coupled to the inner ring;
? an enclosure for housing a copper coil and a printed circuit board, wherein the printed circuit board is configured to sense a change in an inductive field corresponding to the rotational parameter, wherein the enclosure is coupled to the outer ring and the enclosure is stationary relative to the inner ring and the target.