Wireless machine condition monitoring device

Abstract

A condition monitoring device (10) designed to be mounted on a moving machine comprises: a base (12); a printed circuit board assembly (14) extending along a first axis (Z) and fixed to the base (12) by two fixing elements (20, 21), the fixing elements (20, 21) being arranged on a second axis (X) and extending along a third axis (Y) perpendicular to the first and second axes (Z, X); the fixing elements (20, 21) being symmetrical with respect to an axis of symmetry (Z-Z); an integrated power supply (16) connected to the printed circuit board assembly (14); and a sensing element (30) mounted between the two fixing elements (20, 21) and comprising at least two active sensing units (31, 32), the at least two active sensing units (31, 32) being arranged symmetrically with respect to the axis of symmetry (Z-Z) of the fixing elements (20, 21).

Description

Technical Field

[0001] The present invention relates to the field of condition monitoring devices, and in particular to a condition monitoring sensor for monitoring the condition of a system such as a rotating machine. Background Art

[0002] Condition monitoring devices allow the condition of a system to be monitored without manual inspection. These devices can be particularly advantageous in remote locations or locations that are difficult to access and / or dangerous to approach, such as shafts and / or bearings in a wide system of rotating machinery.

[0003] Analyzing vibration signals generated by rotating machines is well known in the art of machine condition monitoring.

[0004] Typically, electrical sensors are used to collect vibration measurements that can later be analyzed to determine the machine condition and detect any machine defects.

[0005] In many cases, it may be convenient to power the condition monitoring device from an integrated generation source. In practice, it may be necessary to provide electrical energy to a device located in a remote location, for example where no power supply infrastructure exists or where, if infrastructure exists, power is unavailable at the particular location where the device is installed.

[0006] In order to power the condition monitoring device, it is known to use a battery pack or a power source of limited capacity, such as an energy harvester.

[0007] Such condition monitoring devices rely on vibrations generated by the machine being monitored.

[0008] Known condition monitoring devices are usually composed of a single vibration sensor connected to a printed circuit board, an amplification circuit for increasing the vibration signal, and a wireless transmitter for sending the vibration information to a display device or an in-depth analysis center.

[0009] Amplifying the signal too much will also amplify the noise in the signal.

[0010] Therefore, there is a need to provide a condition monitoring device for measuring vibration of a rotating machine that can reduce interference (such as noise, distortion, etc.) while transmitting a vibration signal of better quality. Summary of the Invention

[0011] A particular object of the present invention is to provide a condition monitoring device designed to be mounted on a rotating machine (e.g., on the housing of an electric motor) near a rolling bearing, the condition monitoring device comprising: a base, e.g., made of a metal material; a printed circuit board assembly, referred to as a "PCBA," extending along a first axis and fixed to the base by two fastening elements, the fastening elements being arranged on a second axis and extending along a third axis perpendicular to the first and second axes, the fastening elements being symmetrical with respect to a first axis of symmetry parallel to the first axis; an integrated power source, e.g., a battery, connected to the PCBA; and a sensing element, mounted between the two fastening elements and comprising at least two active sensing cells, the at least two active sensing cells being arranged symmetrically with respect to the first axis passing through the axis of symmetry of the fastening elements.

[0012] For example, the first axis may be a vertical axis, the second axis may be a longitudinal axis, and the third axis may be a transverse axis.

[0013] In another embodiment, the first axis may be a transverse axis, the second axis may be a longitudinal axis, and the third axis may be a vertical axis.

[0014] In any case, the fixing element extends along an axis perpendicular to the extension axis of the PCBA.

[0015] The securing element extends along an axis perpendicular to the mounting surface of the base.

[0016] The condition monitoring device is configured to acquire a vibration signal generated by the rotating machine and transmit the vibration signal to a data analyzer in a wireless manner (eg, via a gateway) so as to analyze the received signal and determine the condition of the rotating machine.

[0017] The base allows mechanical fixing of the PCBA and transfers vibrations of the rotating machine to the PCBA.

[0018] Advantageously, the printed circuit board assembly has a lower portion extending downwardly beyond the battery (e.g., a lower end of the battery) along a first axis (e.g., vertically), the sensing element being mounted on the lower portion, and the lower portion being fixed to the base. In this manner, the sensing element is positioned adjacent to the base.

[0019] The two active sensing units are fixed on the front surface of the lower portion of the PCBA so as to be located near a fixed position between the PCBA and the base.

[0020] The base may include: a first fixing portion designed to be fixed to a rotating machine; and a second fixing portion extending upward from the first fixing portion along a first axis and having a substantially flat mounting surface that contacts a lower portion (e.g., a rear surface of the lower portion) of the printed circuit board assembly.

[0021] The first fixing portion is, for example, substantially cylindrical.

[0022] The second fixing portion may have a semi-conical shape.

[0023] Alternatively, the second fixing portion may be semi-cylindrical with a flat mounting surface.

[0024] Thus, the PCBA rests against the flat surface and is fixed by two fixing elements, such as screws that are tightened along the third axis. The fixing elements are positioned symmetrically with respect to the first axis.

[0025] The flatness of the fixing surface is particularly important because the flatter the fixing surface, the better the vibration signal will be transferred from the base to the PCBA. However, for the present invention, the flatness of the fixing surface is not essential.

[0026] According to one embodiment, the two active sensing units are arranged along the first axis, in particular, the two active sensing units are arranged along the symmetry axis of the fixing element.

[0027] According to another embodiment, the two active cells of the sensing element are arranged along a second axis passing through the fixing element.

[0028] According to one embodiment, the sensing element comprises at least three active cells arranged along a first axis passing through the axis of symmetry of the fixed element and symmetrical with respect to a second axis, wherein the second axis passes through one of the active cells.

[0029] According to another embodiment, the sensing element comprises at least four active cells, and the at least four active cells are arranged along the first axis and symmetrically with respect to the second axis.

[0030] According to another embodiment, the sensing element comprises at least four active cells, which are arranged in pairs along the first axis, and a pair of active cells is symmetrical to another pair of active cells with respect to the first axis passing through the axis of symmetry of the fixed element.

[0031] Each active sensing unit may be mounted on an electronic component, or all active sensing units may be mounted on a single electronic component.

[0032] The active sensing unit may be, for example, a piezoelectric element or an accelerometer.

[0033] The fixing surface is slightly offset relative to a plane comprising the first axis and the second axis.However, in another embodiment, the fixing surface may be located in a plane comprising the first axis and the second axis.

[0034] The battery is for example welded on the rear surface of the PCBA. However, the battery can be fixed on the PCBA in any other way.

[0035] The condition monitoring device may include a housing that covers and protects the PCBA and the battery. The housing may be made of a material with high electromagnetic permeability, such as plastic, rubber, resin, or thermoplastic.

[0036] The condition monitoring device may include an antenna for wireless communication, the antenna being positioned in an upper portion of the PCBA.

[0037] The printed circuit board assembly may include a first elongated printed circuit board having a plate shape extending along a vertical axis; and a second elongated printed circuit board having a plate shape extending along the vertical axis.

[0038] The second PCB may be mounted on a front surface of the first PCB opposite the battery. In other words, the printed circuit boards are stacked along a transverse axis.

[0039] For example, the second PCB has specific holes, such as circular through holes, which are used to avoid air bubble effects and increase attachment points between side surfaces of the PCBs during a process of injecting potting compound such as resin.

[0040] For example, the second PCB also has two elliptical through-holes extending along the first axis and used to avoid any interference between tall components on the first PCB and the second PCB. The elliptical through-holes also allow for sufficient potting compound. This particular elliptical shape also provides some tolerance margin and serves as an attachment point between the side surfaces of the PCBs during the potting compound injection process.

[0041] The second PCB may have a smaller size than the first PCB.

[0042] Alternatively, the printed circuit board assembly may include a single printed circuit board or more than two printed circuit boards.

[0043] According to another aspect, the present invention relates to a method for processing a vibration signal received from a condition monitoring device as described above.

[0044] The method includes correlating vibration signals in the time domain respectively provided from active cells of the sensing element to obtain a resulting signal in the frequency domain with better amplitude and reduced noise.

[0045] In fact, due to the specific configuration of the active unit between the fixed elements and symmetrical with respect to a first axis of symmetry passing through the fixed elements, spatially synchronized vibration signals are added.

[0046] The method further includes: amplifying the result signal; and sending the amplified result signal to a data processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The invention and its advantages will be better understood by studying the detailed description of a particular embodiment given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0048] Figure 1 is an exploded perspective view of a condition monitoring device according to an embodiment of the present invention;

[0049] Figure 2a yes Figure 1 A front view of the monitoring device;

[0050] Figure 2b yes Figure 1 A front view of a monitoring device showing two active units in a single sensor unit;

[0051] Figure 3 yes Figure 1 The cross section of the monitoring device;

[0052] Figure 4is a cross section of a monitoring device according to a second embodiment;

[0053] Figure 5 is a front view of a monitoring device according to a third embodiment;

[0054] Figure 6 is a front view of a monitoring device according to a fourth embodiment;

[0055] Figure 7 is a front view of a monitoring device according to a fifth embodiment;

[0056] Figure 8 is a front view of a monitoring device according to a sixth embodiment;

[0057] Figure 9 is a front view of a monitoring device according to a seventh embodiment;

[0058] Figure 10 is a front view of a monitoring device according to an eighth embodiment; and

[0059] Figure 11 is shown to be applied according to Figure 7 Schematic diagram of a signal processing method for a condition monitoring device. DETAILED DESCRIPTION

[0060] In the following description, the terms "longitudinal", "lateral", "vertical", "front", "rear", "left" and "right" are defined according to a common orthogonal reference as shown in the accompanying drawings, which includes: a longitudinal axis X, which is horizontal and runs from left to right in a front view; a transverse axis Y, which is perpendicular to the longitudinal axis X and extends from rear to front in a front view; and a vertical axis Z, which is orthogonal to the longitudinal axis X and the transverse axis Y.

[0061] First refer to Figures 1 to 4 , Figures 1 to 4 An embodiment of a wireless machine condition monitoring device 10 according to the present invention is shown, which is designed to be mounted on a rotating machine (not shown), for example, on the housing of an electric motor, near a rolling bearing.

[0062] The condition monitoring device 10 is configured to acquire raw vibration signals generated by the rotating machine, amplify the signals, process them through a data processor, and wirelessly transmit the vibration signals to a data center (e.g., transmit the vibration signals to the data center via a gateway) to analyze the received signals and determine the condition of the rotating machine.

[0063] The condition monitoring device 10 includes a base 12, such as one made of a metal material; a printed circuit board assembly 14, referred to as a "PCBA," mounted on the base 12; an integrated power source 16, such as a battery, connected to the PCBA 14; a potting compound 17 surrounding the PCBA 14 and the battery 16; and a housing 18 covering and protecting the potting compound 17, the PCBA 14, and the battery 16.

[0064] The housing 18 may be made of a material having high electromagnetic permeability (eg, plastic, rubber, or resin).

[0065] The potting compound 17 is made of, for example, a resin injected into the interior volume 18b defined in the housing 18 through a through hole 18a formed in the housing 18. The potting compound 17 is injected until the level 17a of the potting material is below the inner surface of the upper portion of the housing (e.g., as shown in FIG. 1 ). Figure 4 and Figure 5 The horizontal surface 17a of the potting extends beyond the upper boundary of the PCBA 14 in the axial direction.

[0066] As shown, the antenna 19 is positioned in an upper portion of the PCBA 14 .

[0067] The battery 16 is, for example, soldered to the rear surface of the PCBA 14. However, the battery 16 may be fixed to the PCBA 14 in any other manner.

[0068] As shown, the printed circuit board assembly 14 includes a first elongated printed circuit board (PCB) 14a having a plate shape extending along a first axis Z (here, the first axis Z is vertical); and a second elongated printed circuit board 14b having a plate shape extending along the first axis Z. The second PCB 14b is mounted on the front surface of the first PCB 14a, opposite the battery 16. In other words, the printed circuit boards are stacked along the transverse axis Y. The size of the second PCB 14b is smaller than that of the first PCB 14a.

[0069] Alternatively, printed circuit board assembly 14 may include a single printed circuit board or more than two printed circuit boards.

[0070] As shown, the second PCB 14b has specific holes 15a, 15b, 15c, such as circular through holes 15a, which are used to avoid bubbles during the process of injecting potting compound (e.g., resin) and increase attachment points between side surfaces of the PCBs.

[0071] Second PCB 14b also includes two oblong through-holes 15b and 15c. These oblong through-holes 15b and 15c extend along first axis Z and are used to prevent any interference between tall components on first PCB 14a and second PCB 14b. These oblong through-holes also allow for sufficient potting compound to be accommodated. This particular oblong shape also allows for some tolerance margin and serves as a point of attachment between the side surfaces of the PCBs during the potting compound injection process.

[0072] As in Figure 1 and Figure 3 As can be seen from the figure, the vertical length of the PCB assembly 14 is greater than the length of the battery 16 , such that the lower portion 14 c of the PCB assembly 14 extends beyond the lower end 16 a of the battery 16 in the vertical direction.

[0073] The lower portion 14 c of the PCBA 14 is used to fix the PCBA 14 on the base 12 .

[0074] Thus, the base 12 includes a first fixing portion 12a designed to be fixed to a rotating machine. The first fixing portion 12a is generally cylindrical. The base 12 also includes a second fixing portion 12b extending from the upper surface of the first fixing portion 12a along a first axis (here, the vertical axis Z).

[0075] The second fixing portion 12b has a semiconical shape defined by a planar mounting surface 12c that contacts the rear surface of the lower portion 14c of the PCBA 14. Alternatively, the second fixing portion 12b may be a semi-cylindrical shape having the planar mounting surface 12c.

[0076] Thus, PCBA 14 rests against planar surface 12c and is secured by two fastening elements 20, 21 arranged along a second axis (here, longitudinal axis X). Fastening elements 20, 21 extend along a third axis (here, transverse axis Y). For example, fastening elements 20, 21 are screws that are tightened along the third axis (here, transverse axis Y). Fastening elements 20, 21 are symmetrically positioned relative to vertical axis Z.

[0077] The flatness of the fixing surface 12c is particularly important because the flatter the fixing surface 12c is, the better the vibration signal will be transferred from the base to the PCBA 14. However, the flatness of the fixing surface 12c is not required for the present invention.

[0078] As in Figure 3 and Figure 4 As can be seen from the figure, the fixing surface 12c is slightly offset relative to the plane XZ including the vertical axis Z and the longitudinal axis X. Figure 5 In another embodiment shown above, the fixing surface 12c may be positioned in a plane XZ comprising the vertical axis Z (first axis) and the longitudinal axis X (second axis).

[0079] The base 12 thus allows mechanical fixing of the PCBA 14 and transmission of vibrations of the moving machine to said PCBA 14 .

[0080] The condition monitoring device 10 further includes a sensing element 30 configured to sense vibrations transmitted from the moving machine to the fixed surface 12 c of the base 12 .

[0081] The sensing element 30 is mounted between the two fixing elements 20 and 21. The two fixing elements 20 and 21 are symmetrical with respect to a symmetry axis ZZ passing through the center of the PCBA 14.

[0082] like Figures 1 to 4 As shown, the sensing element 30 includes two active sensing cells 31 and 32 .

[0083] like Figure 2a As shown, each active sensing unit 31, 32 can be mounted on an electronic component, or as shown in FIG. Figure 2b As shown, two active sensing units 31, 32 can be mounted on a single electronic component.

[0084] The active sensing units 31 , 32 may be, for example, piezoelectric elements or accelerometers.

[0085] The two active sensing units 31 , 32 are fixed on the front surface of the lower portion 14 c of the PCBA 14 so as to be located near a fixed position between the PCBA 14 and the base 12 .

[0086] according to Figures 1 to 5 In the first embodiment shown, the two active sensing units 31 , 32 are arranged along a vertical axis Z passing through the axis of symmetry ZZ of the fixing elements 20 , 21 and are symmetrical with respect to the longitudinal axis X.

[0087] Figure 6 The embodiment shown (in which identical components are given identical reference numerals) differs from the preceding embodiment in that the two active cells 31, 32 of the sensing element 30 are arranged along a longitudinal axis X passing through the fixing elements 20, 21 and are symmetrical with respect to a vertical axis Z passing through an axis of symmetry ZZ of the fixing elements 20, 21.

[0088] Figure 7 The embodiment shown (wherein identical components are given identical reference numerals) differs from the preceding embodiment in that the sensing element 30 comprises three active cells 31, 32, 33 arranged along a vertical axis Z passing through the axis of symmetry ZZ of the fixing elements 20, 21 and symmetrically with respect to the longitudinal axis X. The longitudinal axis X therefore passes through one of the active cells 31, 32, 33.

[0089] Figure 8 (wherein the same components are given the same reference numerals) Figures 1 to 4 The embodiment of is different in that the sensing element 30 comprises four active units 31 , 32 , 33 , 34 , which are arranged along a vertical axis and symmetrically with respect to the longitudinal axis X.

[0090] Figure 9 The embodiment shown (in which identical components are given identical reference numerals) differs from the preceding embodiment in that the four active cells 31, 32, 33, 34 of the sensing element 30 are arranged two by two along the vertical axis Z. A pair of active cells 31, 33 is symmetrical to another pair of active cells 32, 34 with respect to the vertical axis Z passing through the axis of symmetry ZZ of the fixing elements 20, 21.

[0091] Figure 10 (wherein the same components are given the same reference numerals) Figure 3 The embodiment differs in that the printed circuit board assembly extends along the transverse axis Y (first axis) and is fixed to the base by two fixing elements 20, 21 (in particular, the printed circuit board assembly is fixed to the mounting surface 12d by two fixing elements 20, 21), and the fixing elements are arranged on the longitudinal axis X (second axis) and extend along a vertical axis (third axis) perpendicular to the transverse axis Y and the longitudinal axis X.

[0092] Typically, a printed circuit board assembly, referred to as a "PCBA," extends along a first axis and is secured to the base by two securing elements disposed on a second axis and extending along a third axis perpendicular to the first and second axes.

[0093] like Figures 1 to 9 As shown, the first axis can be a vertical axis, the second axis can be a longitudinal axis, and the third axis can be a transverse axis. As another option, as Figure 10 As shown, the first axis may be a transverse axis, the second axis may be a longitudinal axis, and the third axis may be a vertical axis.

[0094] In any case, the fixing element extends along an axis that is perpendicular to the extension axis of the PCBA.

[0095] The securing element extends along an axis that is perpendicular to the mounting surface of the base.

[0096] As in Figure 11 As can be seen above, the signal processing method 40 is applied according to Figure 7 The condition monitoring device 10 of the embodiment of FIG. 3 is shown in FIG. 3 , in which the sensing element 30 includes three active units 31 , 32, 33. However, the signal processing method 40 may be applied to the condition monitoring device according to any of the aforementioned embodiments.

[0097] In step 41, the vibration signals S1, S2, S3 in the time domain, respectively provided by the active units 31, 32, 33, are correlated to obtain a resulting signal S in the frequency domain having a better amplitude and no noise, said better amplitude corresponding to the sum of the amplitudes of each signal S1, S2, S3. In practice, due to the particular configuration of the active units between the fixed elements and symmetrical with respect to a vertical axis passing through the axis of symmetry ZZ of said fixed elements, only the spatially synchronized vibration signals are added.

[0098] At step 42, the resultant signal S is amplified, and at step 43, the amplified resultant signal S is sent to a data processor (not shown).

[0099] Thus, the configuration of the active unit allows accurate and distortion-free vibration measurements to be obtained.

[0100] Thanks to the invention, the vibration signal is amplified without increasing the noise and distortion of the signal. Thus, more accurate information about the vibration of the sports machine can be obtained.

Claims

1. A condition monitoring device (10) designed to be mounted on a moving machine, comprising: base (12); A printed circuit board assembly (14) extending along a first axis (Z, Y) and fixed to the base (12) by two fixing elements (20, 21), the fixing elements (20, 21) being arranged on a second axis (X) and extending along a third axis (Y, Z) perpendicular to the first axis and the second axis (Z, X; Y, X), the fixing elements (20, 21) being symmetrical with respect to an axis of symmetry (ZZ, YY); an integrated power supply (16) connected to the printed circuit board assembly (14); and A sensing element (30) is installed between the two fixing elements (20, 21) and comprises at least two active sensing units (31, 32), wherein the at least two active sensing units (31, 32) are configured to be symmetrical relative to an axis of symmetry (ZZ) of the fixing elements (20, 21).

2. The condition monitoring device (10) according to claim 1, characterized in that The printed circuit board assembly (14) has a lower portion (14c) extending downwardly beyond the battery (16) along the first axis, and the lower portion (14c) is fixed to the base (12).

3. The condition monitoring device (10) according to claim 2, characterized in that The base (12) includes: a first fixing portion (12a) designed to be fixed to a rotating machine; and a second fixing portion (12b) extending upward from the first fixing portion (12a) along the first axis and having a flat mounting surface (12c) in contact with a lower portion (14c) of the printed circuit board assembly (14).

4. The condition monitoring device (10) according to any one of the preceding claims, characterized in that The two active sensing units (31, 32) are arranged along the first axis.

5. The condition monitoring device (10) according to any one of claims 1 to 3, characterized in that The two active sensing units (31, 32) of the sensing element (30) are arranged along a second axis (X) passing through the fixing elements (20, 21).

6. The condition monitoring device (10) according to any one of claims 1 to 3, characterized in that The sensing element (30) comprises at least three active sensing units (31, 32, 33), wherein the at least three active sensing units (31, 32, 33) are arranged along a symmetry axis (ZZ) of the fixed element (20, 21) and are symmetrical with respect to the second axis (X).

7. The condition monitoring device (10) according to any one of claims 1 to 3, characterized in that The sensing element (30) comprises at least four active sensing units (31, 32, 33, 34), wherein the at least four active sensing units (31, 32, 33, 34) are arranged along the first axis (Z, Y) and are symmetrical with respect to the second axis (X).

8. The condition monitoring device (10) according to any one of claims 1 to 3, characterized in that The sensing element (30) comprises at least four active sensing units (31, 32, 33, 34), wherein the at least four active sensing units (31, 32, 33, 34) are arranged in pairs along the first axis (Z, Y), and a pair of active sensing units (31, 33) and another pair of active sensing units (32, 34) are symmetrical with respect to the symmetry axis (ZZ) of the fixed element (20, 21).

9. The condition monitoring device (10) according to any one of claims 1 to 3, comprising an antenna (19) for wireless communication, the antenna (19) being positioned in the printed circuit board assembly (14).

10. A method (40) for processing a vibration signal received from a condition monitoring device according to any one of the preceding claims, comprising: - correlating the vibration signals (S1, S2, S3) in the time domain provided respectively from the active sensing units (31, 32, 33) of the sensing element (30) to obtain a resulting signal (S) in the frequency domain having an amplitude (S1+S2+S3) without noise; - amplifying the resulting signal (S); and - sending the amplified result signal to a data processor.

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