Horizontal signal detection sensor with out-of-plane sensitive MEMS accelerometer

Abstract

The utility model discloses a horizontal signal detection sensor with an out-of-plane sensitive MEMS accelerometer, which comprises a main shell, a circuit board module and a first cable, and is characterized in that the main shell is provided with a through hole for the cable to pass through, and the sensor also comprises a cable locking structure for locking the cable on the main shell; the main shell comprises a base with an inner cavity, a cover plate and a pressing structure; the first cable is connected with the circuit board module; the circuit board module is accommodated in the inner cavity and comprises a first circuit board, a second circuit board and a third circuit board; a matching hole is formed in the second side face, opposite to the first side face, of the base, the cover plate is fixed to the base through the matching hole, and the pressing structure is located between the cover plate and the second circuit board, so that the cover plate abuts against the second circuit board through the pressing structure, and the first circuit board is tightly attached to the first side face of the inner cavity of the base. The sensor provided by the utility model can effectively improve the reliability of vibration impact signal acquisition in the horizontal direction.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer. Background Art

[0002] In the rail transit industry, EMUs operate at high speeds, and the high-speed running gear rotating parts are prone to overheating and excessive vibration and impact. This can lead to failures in motors and gearboxes, impacting operating safety. To ensure EMU operating safety, it is necessary to monitor the temperature, vibration, and impact signals of fault-prone locations of running gear rotating parts, such as axle boxes and motors. When abnormal signals occur, timely warnings can be issued to prevent EMUs from operating with problems.

[0003] In the field of vibration and shock signal detection and fault diagnosis, foreign comb-tooth MEMS accelerometers are now mostly used as the core sensitive components of the sensor. Their sensitive axis is in the in-plane direction. The MEMS accelerometer is horizontally mounted on the PCB and then installed inside the sensor housing along with the PCB. After installation, the PCB is vertical and in the same direction as the signal. Only the cut edge contacts the housing in the signal direction. This installation method has a complex signal transmission path. In addition, the sensor structure has a packaging stress effect on the MEMS accelerometer, resulting in low accuracy in detecting low-frequency and weak vibration and shock signals.

[0004] In summary, how to provide a sensor that meets the product requirements of the rail transit industry, can monitor temperature, vibration and shock, and has good signal reliability is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In order to solve the above technical problems, the purpose of the present utility model is to provide a horizontal signal detection sensor with an out-of-plane sensitive MEMS accelerometer and reliable detection.

[0006] The technical solutions provided by this utility model are as follows:

[0007] A horizontal signal detection sensor with an out-of-plane sensitive MEMS accelerometer, comprising a main housing, a circuit board module, a first cable, and a cable locking structure; the main housing comprises a base with an inner cavity, a cover plate, and a pressing structure; a first side surface of the base is provided with a through-hole for a first cable to pass through; the cable locking structure locks the first cable to the through-hole on the first side surface of the base; the first cable is connected to the circuit board module through the through-hole; the circuit board module is accommodated in the inner cavity of the base, comprising a first circuit board, a second circuit board, and a third circuit board; the first surface of the first circuit board is attached to the first side surface of the inner cavity of the base An out-of-plane sensitive MEMS accelerometer is attached to the second surface opposite to the first surface, the second circuit board is vertically clamped on one side of the second surface of the first circuit board, and the first circuit board and the second circuit board are connected through a third circuit board, and the third circuit board is a flexible circuit board; the base is provided with a matching hole on the second side surface opposite to the first side surface, the cover is fixed to the base through the matching hole, the clamping structure is located between the cover plate and the second circuit board, so that the cover plate is pressed against the second circuit board through the clamping structure, so as to make the first circuit board close to the first side surface of the inner cavity of the base; the first side surface is in contact with the surface to be detected of the device to be detected.

[0008] Preferably, the out-of-plane sensitive MEMS accelerometer is a butterfly-wing MEMS accelerometer, a colibrys capacitive accelerometer, or a single torsional pendulum MEMS accelerometer.

[0009] Preferably, a conditioning circuit for conditioning and outputting the collected vibration and impact signals is provided on the second circuit board, and the first cable is connected to the second circuit board.

[0010] Preferably, the cable locking structure includes an embedded tube, a compression cap, and a rubber protective tube. The embedded tube, the compression cap, and the rubber protective tube are all provided with through holes for the first cable to pass through. The front end of the embedded tube is fixed on the through hole of the base, and the rear end is sequentially sleeved with the rubber protective tube and the compression cap. The compression cap can cooperate with the embedded tube to clamp the rubber protective tube after being deformed by pressure.

[0011] Preferably, the clamping structure is a clamping strip, and recessed portions are provided on both sides of the matching hole of the base, and each of the clamping strips is respectively embedded in the recessed portions on both sides.

[0012] Preferably, the second circuit board is provided with a groove at one end close to the pressing strip, the position of the groove corresponds to the depressed portion, and the pressing strip is embedded in the groove.

[0013] Preferably, the hole wall of the base matching hole includes a step surface that is wider on the outside and narrower on the inside, and a groove for positioning the second circuit board is provided on the top of the step surface extending inward.

[0014] Preferably, the recessed portions on both sides of the fitting hole are provided on the step surface.

[0015] Preferably, an end of the second circuit board opposite to the groove is provided with a clearance groove for avoiding the accelerometer.

[0016] Preferably, the method further comprises a stress isolation cover provided on the accelerometer for isolating the accelerometer from the potting glue filled in the inner cavity of the base.

[0017] Preferably, the first side surface of the base is provided with a relief cut surface, and the perforation and cable locking structure are provided on the relief cut surface; the second circuit board is provided with a relief cut edge corresponding to the top corner close to the first side surface; the first circuit board is close to the first side surface of the inner cavity of the base and is located below the relief cut surface.

[0018] Preferably, it also includes a temperature probe, which includes a temperature sensitive element, a second cable, and a probe housing. The temperature sensitive element is connected to the second cable, and the temperature sensitive element is fixed in the probe housing. The probe housing is provided with a thermally conductive insulating resin glue, and a flange is provided at the tail of the probe housing. A mounting hole is provided at the bottom of the base corresponding to the flange, and the probe housing is fixed to the base through the flange and the mounting hole; the second cable passes through the mounting hole into the inner cavity of the main housing and then passes out through the through hole.

[0019] Compared to the prior art, the present invention features a horizontal signal detection sensor with an out-of-plane-sensitive MEMS accelerometer. It employs an out-of-plane-sensitive axial MEMS accelerometer as its core vibration and shock sensor, offering high sensitivity, a wide range, and a wide frequency response. By providing a circuit board module comprising a first circuit board, a second circuit board, and a third circuit board, and a clamping structure, and by using a cover plate and the clamping structure to press the second circuit board against the side of the base cavity, the first circuit board is pressed against the inner surface of the base. This effectively improves the reliability of horizontal vibration and shock signal acquisition (vibration signal acquisition perpendicular to the mounting surface). Furthermore, the out-of-plane-sensitive MEMS accelerometer is attached to the first circuit board, which is in turn attached to the base. This simplifies the signal transmission path and increases the contact area between the base and the MEMS accelerometer, making it easier for the MEMS accelerometer to receive vibration and shock signals, enabling true sensitivity to vibration and shock signals. This minimizes shock signal transmission attenuation and improves sensor signal reliability. Furthermore, the second circuit board is vertically mounted to the first circuit board via a mortise and tenon joint structure, effectively reducing the sensor's size and meeting installation requirements in confined spaces. The overall probe-type structural design meets the installation requirements of the horizontal vibration and impact signal collection and monitoring positions of the EMU's axle boxes, motors and other running gear rotating parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a three-dimensional exploded schematic diagram of a horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 A schematic diagram of a three-dimensional combination of the sensors shown;

[0023] Figure 3 for Figure 1 a cross-sectional view of the sensor shown;

[0024] Figure 4 for Figure 1 A three-dimensional schematic diagram of the base of the sensor shown;

[0025] Figure 5 for Figure 1 A three-dimensional schematic diagram of the circuit board module in the sensor shown;

[0026] Figure 6 for Figure 1 A three-dimensional schematic diagram of the sensor circuit board module in the unfolded state is shown. DETAILED DESCRIPTION

[0027] In order to help those skilled in the art better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0028] It should be noted that when an element is referred to as being “fixed on” or “set on” another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being “connected to” another element, it can be directly connected to the other element or indirectly connected to the other element.

[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" or "several" means two or more, unless otherwise specifically defined.

[0031] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the efficacy and purpose that can be achieved by this application.

[0032] like Figures 1 to 6 As shown, an embodiment of the present invention provides a horizontal signal detection sensor featuring an out-of-plane sensitive MEMS accelerometer for detecting vibration and impact signals horizontal to the mounting surface. The sensor comprises a main housing 1, a circuit board module 2, a temperature probe 4, a first cable 5, and a cable locking structure. The main housing 1 includes a base 11, which has an internal cavity for accommodating components such as the circuit board module 2.

[0033] In this embodiment, the circuit board module 2 includes a first circuit board 21, a second circuit board 22, and a flexible circuit board 23. The first circuit board 21 is equipped with an out-of-plane sensitive MEMS accelerometer 7 for collecting vibration and impact signals. It is located on the first side (rear side) of the inner cavity of the base 11. The out-of-plane sensitive MEMS accelerometer can be a butterfly-wing MEMS accelerometer, a colibrys capacitive accelerometer, or a single torsion pendulum MEMS accelerometer. A stress isolation cover 8 can be provided above the accelerometer 7 to isolate the accelerometer 7 from the potting compound filling the inner cavity of the base 11. The second circuit board 22 is equipped with a conditioning circuit for conditioning and outputting the collected vibration and impact signals. The first and second circuit boards 21, 22 are connected via the flexible circuit board 23. The second circuit board 22 is secured to the first circuit board 21 via a mortise and tenon joint. The arrangement of the first circuit board 21, the second circuit board 22, and the flexible circuit board 23, with the second circuit board 22 secured to the first circuit board 21 via a mortise and tenon joint, results in a more compact structure with a smaller cross-section, convenient and reliable assembly, and facilitates compression by the clamping mechanism.

[0034] In this embodiment, the main housing 1 further includes a cover plate 12 and a clamping structure. The base 11 is provided with a through-hole 110 on the first side surface (rear side) for the first cable 5 to pass through, and a matching hole 111 is provided on the second side surface (front side) opposite to the first side surface. The cover plate 12 is fixed to the base 11 through the matching hole 111. The hole wall of the matching hole 111 of the base 11 includes a stepped surface that is wide on the outside and narrow on the inside to facilitate the installation of the cover plate 12. A groove 115 is provided inwardly extending from the top of the stepped surface for positioning the second circuit board 22. A mounting hole 112 for mounting the temperature probe 4 is provided at the bottom of the base 11. The first side surface of the base 11 is also provided with a relief cut surface 116, and the through-hole 110 and the cable locking structure are provided on the relief cut surface 116. The first circuit board 21 is close to the first side surface of the inner cavity of the base 11 and is located below the relief cut surface 116.

[0035] The clamping structure is located between the cover plate 12 and the second circuit board 22, so that the cover plate 12 is pressed against the second circuit board 22 through the clamping structure, so as to hold the first circuit board 21 tightly against the first side surface of the inner cavity of the base 11. The first side surface is in contact with the surface to be detected of the device to be detected. The bottom of the base 11, which is provided with the temperature probe 4, serves as the mounting surface of the sensor, and is mounted on the device to be detected through this mounting surface. It can be seen that since the mounting surface of this sensor is perpendicular to the surface to be detected, this sensor is suitable for detecting vibration and impact signals horizontal to the mounting surface. In this embodiment, the clamping structure is two clamping strips 31. Both sides of the matching hole 111 of the base 11 are provided with a recessed portion 113 on the stepped surface. The second circuit board 22 is provided with a groove 221 at one end close to the clamping structure. The clamping strips 31 are respectively embedded in the recessed portions 113 and the groove 221 on both sides, and the recessed portions 113 and the groove 221 are used to limit the clamping strips 31. Of course, in other embodiments, other structures can also be used. An end of the second circuit board 22 opposite to the groove 221 is provided with a clearance groove 222 for avoiding the accelerometer 7. A clearance edge 223 is provided at the top corner of the second circuit board 22 close to the first side surface and corresponding to the clearance cut surface 116.

[0036] In this embodiment, the end of the first cable 5 is welded to the second circuit board 22. After the circuit board module is installed in the inner cavity of the base 11, the first circuit board 21 is located below the through hole 110, and the end of the first cable 5 can extend into the inner cavity and be welded to the second circuit board 22.

[0037] The cable locking structure is used to securely lock the first cable 5 to the base 11 after the circuit board module 2 and the first cable 5 are welded and installed in the base 11. In this embodiment, the cable locking structure includes an embedded tube 61, a compression cap 62, and a rubber protective tube 63. Each of these features a through-hole for the first cable 5 to pass through. The front end of the embedded tube 61 passes through a through-hole 110 and is secured to the base 11. The rear end of the embedded tube 61 is sequentially fitted with the rubber protective tube 63 and the compression cap 62. The compression cap 62, after deforming under pressure, cooperates with the embedded tube 61 to securely hold the rubber protective tube 63. Resin glue can also be poured into the rear end of the embedded tube 61. Once the resin glue solidifies, it secures the first cable 5 in the embedded tube 61 and seals the rear end of the embedded tube 61. In this embodiment, the outer diameter of the embedded tube 61 is slightly larger than the inner diameter of the rubber protective tube 63, ensuring a tight fit between the two. Barbs 611 are provided on the embedded tube 61 to prevent the rubber protective tube 63 from falling out. Flat surfaces 612 are also provided on the embedded tube 61 at the barbs 611 to prevent the rubber cable protection tube from rotating. Of course, in other embodiments, other different cable locking structures may also be employed.

[0038] The temperature probe 4 is used to detect temperature. In this embodiment, the temperature probe 4 includes a temperature-sensitive element (not shown), a second cable 41, and a probe housing 42. The temperature-sensitive element and the front end of the second cable 41 are installed in the probe housing 42 and then potted with a thermally conductive insulating resin adhesive. The rear end of the probe housing 42 is provided with a flange, which is installed in the mounting hole 112 of the base 11. The flange is press-fitted with the base 11 through interference fit and then laser welded. The rear end of the second cable 41 enters the inner cavity of the base 11 through the mounting hole 112 and then exits the main housing 1. Of course, in other embodiments, the temperature probe 4 can also adopt other structures, or the temperature probe can be omitted as needed.

[0039] The sensor of this embodiment is assembled as follows: After the circuit board module 2 is pre-assembled, it is welded to the first cable 5 and then installed into the inner cavity of the base 11 from the front through the mating hole 111 (the tail end of the first cable 5 extends rearward through the perforation 110). Once it reaches the predetermined position, the clamping strip 31 is pressed into the mating hole 111 of the base 11, and the cover 12 is then installed in the mating hole 111. The cover 12 and the base 11 are press-fitted together and then laser welded to secure them. The cover 12 applies pressure to the second circuit board 22 via the clamping strip 31. This pressure is transmitted to the first circuit board 21 through the second circuit board 22, firmly pressing the first circuit board 21 against the first side surface of the inner cavity of the base 11, so that the first circuit board 21 and the base 11 are in contact, effectively improving the reliability of the horizontal vibration impact signal acquisition. At the rear of the base 11, the front end of the embedded tube 61 is fixed to the base 11, and a low-flowing resin glue is poured into the rear end of the embedded tube 61. Once the resin glue solidifies, it secures the first cable 5 in the embedded tube 61 and seals the rear end of the embedded tube 61. A compression cap 62 is placed on the rear rubber protective plate and then inserted into the embedded tube 61. After the rubber protective tube 63 and compression cap 62 are in place, a hydraulic mold is used to squeeze the compression cap 62. Once the compression cap 62 is deformed, it fits into the embedded tube 61 and secures the rubber protective tube 63.

[0040] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer, characterized in that: The device comprises a main housing, a circuit board module, a first cable, and a cable locking structure. The main housing comprises a base having an inner cavity, a cover plate, and a pressing structure. A through-hole is provided on a first side surface of the base for the first cable to pass through, and the cable locking structure locks the first cable to the through-hole on the first side surface of the base. The first cable is connected to the circuit board module through the through-hole. The circuit board module is accommodated in the inner cavity of the base and comprises a first circuit board, a second circuit board, and a third circuit board. The first surface of the first circuit board is attached to the first side surface of the inner cavity of the base, and an out-of-plane sensitive MEMS accelerometer is attached to a second surface opposite to the first surface. The second circuit board is vertically clamped to one side of the second surface of the first circuit board, and the first and second circuit boards are connected via a third circuit board. The third circuit board is a flexible circuit board. The base has a mating hole on a second side surface opposite to the first side surface. The cover plate is fixed to the base through the mating hole. The pressing structure is located between the cover plate and the second circuit board, so that the cover plate presses against the second circuit board through the pressing structure to hold the first circuit board in close contact with the first side surface of the inner cavity of the base. The first side surface contacts the surface to be inspected of the device to be inspected.

2. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: The out-of-plane sensitive MEMS accelerometer is a butterfly-wing MEMS accelerometer, a colibrys capacitive accelerometer, or a single torsion pendulum MEMS accelerometer.

3. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: The second circuit board is provided with a conditioning circuit for conditioning and outputting the collected vibration and impact signals, and the first cable is connected to the second circuit board.

4. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: The cable locking structure includes an embedded tube, a compression cap, and a rubber protective tube. The embedded tube, the compression cap, and the rubber protective tube are all provided with through holes for the first cable to pass through. The front end of the embedded tube is fixed on the through hole of the base, and the rear end is sequentially sleeved with the rubber protective tube and the compression cap. The compression cap can cooperate with the embedded tube to clamp the rubber protective tube after being deformed by pressure.

5. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: The clamping structure is a clamping strip, and recessed portions are provided on both sides of the matching hole of the base, and each of the clamping strips is respectively embedded in the recessed portions on both sides.

6. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 5, characterized in that: The second circuit board is provided with a groove at one end close to the pressing strip. The position of the groove corresponds to the depressed portion, and the pressing strip is embedded in the groove.

7. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 5, characterized in that: The hole wall of the base matching hole includes a step surface that is wider on the outside and narrower on the inside, and a groove for positioning the second circuit board is provided on the top of the step surface extending inward.

8. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 7, wherein: The recessed portions on both sides of the fitting hole are provided on the step surface.

9. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 6, wherein: An end of the second circuit board opposite to the groove is provided with a clearance groove for avoiding the accelerometer.

10. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: It also includes a stress isolation cover which is arranged on the accelerometer and is used to isolate the accelerometer from the potting glue filled in the inner cavity of the base.

11. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: The first side surface of the base is provided with a relief cut surface, and the perforation and cable locking structure are provided on the relief cut surface; the second circuit board is provided with a relief cut edge corresponding to the top corner close to the first side surface; the first circuit board is close to the first side surface of the inner cavity of the base and is located below the relief cut surface.

12. The horizontal signal detection sensor having an out-of-plane sensitive MEMS accelerometer according to claim 1, wherein: It also includes a temperature probe, which includes a temperature sensitive element, a second cable, and a probe housing. The temperature sensitive element is connected to the second cable, and the temperature sensitive element is fixed in the probe housing. The probe housing is provided with a heat-conductive insulating resin glue. The tail of the probe housing is provided with a flange, and the bottom of the base is provided with a mounting hole corresponding to the flange. The probe housing is fixed to the base through the flange and the mounting hole; the second cable passes through the mounting hole into the inner cavity of the main housing and then passes out through the through hole.

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