Acceleration sensor

Abstract

The acceleration sensor comprises a shell, a top cover and connecting pieces, the top of the shell is fixedly connected with the top cover, the four corners of the top cover are connected with the connecting pieces in an inserted mode, and the connecting pieces are in threaded connection with the four corners of the top face of the shell; the inner side of the shell is fixedly connected with a plate body, a capacitor is installed on the top face of the plate body, and the interior of the capacitor is elastically connected with a mass block. The utility model has the advantages that the contact part of the top cover and the shell is filled with the gasket, the top cover and the shell jointly extrude the gasket to realize preliminary sealing, meanwhile, the bottom surface of the top cover is etched with a plurality of circles of V-shaped grooves, and a plurality of sealing sheets at the bottom openings of the V-shaped grooves are pressed on the top surface of the gasket to realize multi-sealing, and due to the design of the V-shaped grooves, even if external dust enters gaps, the dust only enters the V-shaped grooves; an internal plate body and a capacitance area are avoided, the influence of pollutants is greatly reduced, and the device is suitable for high-dust industrial vibration scenes.

Description

Technical Field

[0001] This utility model relates to the field of sensor technology, and in particular to an acceleration sensor. Background Technology

[0002] Accelerometers are widely used in industrial vibration monitoring, automotive safety systems, and other fields. Currently, MEMS (Micro-Electro-Mechanical Systems) accelerometers have become mainstream due to their small size and low cost. However, in high-dust, high-humidity industrial environments, existing technologies have significant drawbacks:

[0003] Insufficient sealing reliability: Traditional sealing structures are prone to micro-gaps under long-term vibration, allowing metal dust particles larger than 5μm to intrude; although potting compound sealing can prevent dust, the curing stress affects the displacement accuracy of the mass block (error up to ±0.5g), and it cannot be maintained after failure; dust accumulation in the gap between capacitor electrodes (typically 3-5μm) can lead to short circuits or signal drift. Therefore, an accelerometer is proposed to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to at least solve one of the aforementioned technical defects.

[0005] Therefore, one objective of this invention is to provide an acceleration sensor to solve the problems mentioned in the background art and overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, one embodiment of the present invention provides an accelerometer, including a housing, a top cover, and connectors. The side of the housing is engraved with an indicator arrow, the top cover is fixedly connected to the top of the housing, and connectors are inserted into the four corners of the top cover. The connectors are threadedly connected to the four corners of the top surface of the housing.

[0007] A plate is fixedly connected to the inner side of the outer shell, a capacitor is installed on the top surface of the plate, a mass block is elastically connected inside the capacitor, and an electrode plate is fixedly connected inside the capacitor.

[0008] The mass block has extensions on both sides, and the distance between the electrode portion and the extensions can be varied.

[0009] The output terminal of the capacitor is connected to the MEMS chip, and the output terminal of the MEMS chip is fixedly connected to an output line;

[0010] A padding layer is filled between the contact surfaces of the top cover and the outer shell. Several V-grooves are formed on the bottom surface of the top cover. A sealing sheet is fixedly connected to the bottom opening of the V-groove and the sealing sheet is pressed on the padding layer.

[0011] Preferably, the outer shell and top cover are made of aluminum, and the connecting parts are specifically hexagonal screws.

[0012] Using the above technical solution: This accelerometer is divided into two parts: the body, which consists of a shell, a top cover, connectors, a pad, and a sealing sheet.

[0013] The working part consists of a plate, capacitor, mass block, electrode plate, MEMS chip, and output line structure.

[0014] The working principle is as follows: a mass block, typically made of silicon, acts as an inertial sensing element, displacing under acceleration. Elastic beams at both ends of the mass block support it and provide restoring force to limit the displacement range. Several extensions on both sides of the mass block serve as movable electrodes, while the plate portion is a stationary electrode connected to the substrate. When the sensor is subjected to acceleration, the mass block displaces due to inertia, causing a change in the distance between the movable electrodes and the plate portion. This displacement changes the electrode distance d, and the capacitance C∝1 / d. This capacitance change is converted into a voltage signal, which is then output through the output line, thus achieving acceleration sensing.

[0015] Preferably, in any of the above embodiments, the mass block is comb-shaped as a whole, and both ends of the mass block are elastic.

[0016] Preferably, in any of the above embodiments, the mass block can move left and right on a predetermined axis on the top surface of the capacitor.

[0017] The top cover structure has been improved. A gasket is filled at the contact point between the top cover and the outer shell. The top cover and the outer shell work together to compress the gasket to achieve a preliminary seal. At the same time, multiple V-grooves are etched on the bottom surface of the top cover. Multiple sealing pieces are pressed against the top surface of the gasket at the bottom of the V-grooves to achieve multiple seals. The V-groove design ensures that even if external dust enters the gap, it will only enter the V-groove, avoiding contaminants from entering the internal plate and capacitor areas. This significantly reduces the impact of contaminants and makes it suitable for high-dust industrial vibration scenarios.

[0018] Preferably, in any of the above embodiments, the output line passes through the housing, and the housing is filled with a rubber sealing ring at the point where the output line passes through.

[0019] The above technical solution is adopted as follows: The device consists of a square aluminum outer shell with laser-engraved indicator arrows on the sides (marking the installation direction). The top cover (made of 5052 aluminum alloy) is fastened to the top of the shell by an internal hexagonal connector, with the fastening torque controlled at 1.2 N·m ± 0.1 N·m. The contact surface between the top cover and the outer shell is filled with a silicone pad (0.5 mm thick, Shore A hardness 60A), which expands and fills the micro-gaps at the interface when compressed.

[0020] Innovative sealing structure: Three concentric V-grooves (0.3mm deep, 50° angle) are etched on the bottom surface of the top cover. A ring-shaped rubber sealing sheet (0.2mm thick) is pasted at the bottom of each V-groove, and the lower surface of the sealing sheet is tightly fitted to the top surface of the padding layer.

[0021] In the working section, an alumina ceramic plate is fixed to the bottom of the outer casing, and a capacitor is integrated on the top surface of the plate. The capacitor contains a single-crystal silicon mass (comb-shaped design, 20μm tooth width), with both ends of the mass connected to the base via elastic beams (elasticity coefficient 1.8N / m). The electrode portion is a gold-plated fixed electrode, forming multiple capacitor pairs (initial spacing 3μm) with the extension of the mass. A MEMS chip (ASIC signal conditioning circuit) is soldered to the edge of the plate and connected to the capacitor output terminal via gold wire bonding. The output line (silver-plated copper core) passes through the side wall of the outer casing, with a fluororubber sealing ring at the wire hole.

[0022] Preferably, in any of the above embodiments, the pad is made of silicone, the opening of the V-groove faces outward, and the inclination angle of the V-groove is 45-55 degrees.

[0023] Working principle of this device: acceleration sensing

[0024] When the sensor is subjected to X-axis acceleration, the inertial force causes the mass block to move laterally along the top surface of the plate; the distance d between the extensions (movable electrodes) on both sides of the mass block and the plate changes, and the capacitance value C changes according to the formula: C∝1 / d. The MEMS chip converts the capacitance difference signal into a differential voltage, which is then output to the external acquisition system via the output line.

[0025] Multiple sealing and dustproof mechanisms

[0026] ① Primary sealing: When the connector is tightened, the silicone gasket is compressed and fills the interface between the top cover and the outer shell (sealing pressure > 0.5MPa);

[0027] ② Secondary capture: If external dust penetrates into the interface, it slides into the annular cavity along the V-groove angle (captured particle size > 5μm);

[0028] ③ Three-level blocking: The sealing sheet covers the bottom opening of the V-groove to prevent dust from entering the plate area.

[0029] Preferably, the sealing sheet is made of rubber, as described in any of the above embodiments.

[0030] Compared with the prior art, the advantages and beneficial effects of this utility model are as follows:

[0031] This accelerometer features an improved top cover structure. A gasket is placed at the contact point between the top cover and the outer shell, and the top cover and outer shell work together to press the gasket to achieve a preliminary seal. At the same time, multiple V-grooves are etched on the bottom surface of the top cover, and multiple sealing plates are pressed against the top surface of the gasket at the bottom of the V-grooves to achieve multiple seals. The V-groove design ensures that even if external dust enters the gap, it will only enter the V-groove, avoiding contaminants from entering the internal plate and capacitor area. This significantly reduces the impact of contaminants and makes it suitable for high-dust industrial vibration scenarios.

[0032] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0034] Figure 1 This is a schematic diagram of the structure of this utility model;

[0035] Figure 2 This is a partial structural diagram of the junction between the outer shell and the top cover of this utility model;

[0036] Figure 3 This is a schematic diagram of the structure of the plate body of this utility model.

[0037] In the diagram: 1-outer shell, 3-top cover, 4-connector, 5-plate, 6-capacitor, 7-mass block, 8-electrode plate, 9-MEMS chip, 10-output line, 11-gasket, 12-V groove, 13-sealing plate. Detailed Implementation

[0038] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0039] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0040] like Figure 1-3 As shown, this accelerometer includes a housing 1, a top cover 3, and connectors 4. Indicator arrows are engraved on the side of the housing 1. The top cover 3 is fixedly connected to the top of the housing 1. Connectors 4 are inserted into the four corners of the top cover 3 and are threaded to the four corners of the top surface of the housing 1.

[0041] A plate 5 is fixedly connected to the inner side of the outer casing 1. A capacitor 6 is installed on the top surface of the plate 5. A mass block 7 is elastically connected inside the capacitor 6. An electrode plate 8 is fixedly connected inside the capacitor 6.

[0042] The mass block 7 has extensions on both sides, and the distance between the electrode plate 8 and the extensions can be varied;

[0043] The output terminal of capacitor 6 is connected to MEMS chip 9, and the output terminal of MEMS chip 9 is fixedly connected to output line 10.

[0044] A pad 11 is filled between the contact surfaces of the top cover 3 and the outer shell 1. Several V-grooves 12 are opened on the bottom surface of the top cover 3. A sealing sheet 13 is fixedly connected to the bottom opening of the V-groove 12 and the sealing sheet 13 is pressed on the pad 11.

[0045] Example 1: The outer casing 1 and top cover 3 are made of aluminum, and the connecting part 4 is specifically a hexagonal screw. The mass block 7 is comb-shaped, and both ends of the mass block 7 are elastic. The mass block 7 can move left and right on a predetermined axis on the top surface of the capacitor 6. The output line 10 passes through the outer casing 1, and a rubber sealing ring is filled at the point where the output line 10 passes through the outer casing 1. The pad 11 is made of silicone, the groove 12 has its opening facing outward, and the inclination angle of the V-groove 12 is 45-55 degrees. The sealing sheet 13 is made of rubber.

[0046] Example 2: This accelerometer consists of two parts: the main body, which comprises a shell 1, a top cover 3, a connector 4, a pad 11, and a sealing sheet 13; and the working part, which comprises a plate 5, a capacitor 6, a mass block 7, an electrode plate 8, a MEMS chip 9, and an output line 10. The working principle is as follows: the mass block 7, typically made of silicon, acts as an inertial sensing element, displacing under acceleration. The two ends of the mass block 7 are elastic beams that support the mass block and provide restoring force to limit the displacement range. Several extensions on both sides of the mass block 7 serve as movable electrodes, while the electrode plate 8 is a stationary electrode connected to the substrate. When the sensor is subjected to acceleration, the mass block 7 displaces due to inertia, causing a change in the distance between the movable electrodes and the electrode plate 8. This displacement changes the electrode distance d, and the capacitance C ∝ 1 / d. This capacitance change is converted into a voltage signal, which is then output through the output line 10, thus realizing the sensing of acceleration. The device's structure includes: a square aluminum shell 1 with laser-engraved indicator arrows on the sides (marking the installation direction). The top of the outer shell 1 is fastened to the top cover 3 (made of 5052 aluminum alloy) by four internal hexagonal connectors 4, with the fastening torque controlled at 1.2 N·m ± 0.1 N·m. The contact surface between the top cover 3 and the outer shell 1 is filled with a silicone pad layer 11 (thickness 0.5 mm, Shore hardness 60A), which expands and fills the micro gaps at the interface when compressed.

[0047] Innovative sealing structure: Three concentric V-grooves 12 (groove depth 0.3mm, inclination angle 50°) are etched on the bottom surface of the top cover 3. An annular rubber sealing sheet 13 (thickness 0.2mm) is pasted at the bottom opening of each V-groove 12, and the lower surface of the sealing sheet 13 is tightly fitted to the top surface of the pad 11.

[0048] In the working part, the alumina ceramic plate 5 is fixed to the bottom of the outer casing 1, and the top surface of the plate 5 integrates a capacitor 6. The capacitor 6 contains a single-crystal silicon mass block 7 (comb-shaped design, 20μm tooth width), and the two ends of the mass block 7 are connected to the base via elastic beams (elasticity coefficient 1.8N / m). The electrode portion 8 is a gold-plated fixed electrode, forming 8 capacitor pairs (initial spacing 3μm) with the extension of the mass block 7. The MEMS chip 9 (ASIC signal conditioning circuit) is soldered to the edge of the plate 5 and connected to the output terminal of the capacitor 6 via gold wire bonding. The output line 10 (silver-plated copper core) passes through the side wall of the outer casing 1, and a fluororubber sealing ring is installed at the wire hole.

[0049] The working principle of this utility model is as follows:

[0050] Accelerometer

[0051] When the sensor is subjected to X-axis acceleration, the inertial force causes the mass block 7 to move laterally along the top surface of the plate 5; the distance d between the extensions (movable electrodes) on both sides of the mass block 7 and the electrode plate 8 changes, and the capacitance value C changes according to the formula: C∝1 / d. The MEMS chip 9 converts the capacitance difference signal into a differential voltage, which is output to the external acquisition system via the output line 10.

[0052] Multiple sealing and dustproof mechanisms

[0053] ① Primary sealing: When the connector 4 is locked, the silicone pad 11 is compressed and fills the interface between the top cover 3 and the outer shell 1 (sealing pressure > 0.5MPa).

[0054] ② Secondary capture: If external dust penetrates into the interface, it slides into the annular groove cavity along the V groove at an angle of 12 (captured particle size > 5μm);

[0055] ③ Three-level blocking: The sealing sheet 13 covers the bottom opening of the V groove 12 to prevent dust from entering the plate body area 5.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] This accelerometer improves the structure of the top cover 3. A gasket 11 is filled at the contact point between the top cover 3 and the outer shell 1. The top cover 3 and the outer shell 1 together compress the gasket 11 to achieve a preliminary seal. At the same time, multiple V-grooves 12 are etched on the bottom surface of the top cover 3. Multiple sealing pieces 13 are pressed on the top surface of the gasket 11 at the bottom opening of the V-groove 12 to achieve multiple seals. The design of the V-groove 12 ensures that even if external dust enters the gap, it will only enter the V-groove 12, avoiding the internal plate 5 and capacitor area. The impact of contaminants is greatly reduced, making it suitable for high-dust industrial vibration scenarios.

Claims

1. An acceleration sensor, characterized in that, Includes a shell (1), a top cover (3), and connectors (4). The top cover (3) is fixedly connected to the top of the shell (1), and connectors (4) are inserted into the four corners of the top cover (3). The connectors (4) are threaded to the four corners of the top surface of the shell (1). A plate (5) is fixedly connected to the inner side of the outer shell (1), a capacitor (6) is installed on the top surface of the plate (5), a mass block (7) is elastically connected inside the capacitor (6), and an electrode plate (8) is fixedly connected inside the capacitor (6). The mass block (7) has extensions on both sides, and the distance between the electrode plate (8) and the extensions can vary; The output terminal of the capacitor (6) is connected to the MEMS chip (9), and the output terminal of the MEMS chip (9) is fixedly connected to the output line (10). A pad (11) is filled between the contact surfaces of the top cover (3) and the outer shell (1). Several V-grooves (12) are opened on the bottom surface of the top cover (3). A sealing sheet (13) is fixedly connected to the bottom opening of the V-groove (12). The sealing sheet (13) is pressed on the pad (11).

2. An acceleration sensor as described in claim 1, characterized in that: The outer shell (1) and top cover (3) are made of aluminum, and the connector (4) is specifically an internal hex screw.

3. An acceleration sensor as described in claim 2, characterized in that: The mass block (7) is comb-shaped, and both ends of the mass block (7) are elastic.

4. An acceleration sensor as described in claim 3, characterized in that: The mass block (7) can move left and right on a predetermined axis on the top surface of the capacitor (6).

5. An acceleration sensor as described in claim 4, characterized in that: The output line (10) passes through the housing (1), and the housing (1) is filled with a rubber sealing ring at the point where the output line (10) passes through.

6. An acceleration sensor as described in claim 5, characterized in that: The pad (11) is made of silicone, the opening of the V groove (12) faces outward, and the inclination angle of the V groove (12) is 45-55 degrees.

7. An acceleration sensor as described in claim 6, characterized in that: The sealing sheet (13) is made of rubber.

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