A depth sensor

Abstract

The application relates to a depth sensor, which comprises a shell, an internal through accommodating cavity, a water pressure sensing element arranged in the accommodating cavity, a protruding sensing element in the middle part, a seat part of the sensing element in sealing connection with a fixed cover, a head part for sensing pressure deformation, the fixed cover being fixed in the accommodating cavity and in sealing connection with the shell, the head part being located in a through hole in the middle part of the fixed cover corresponding to the sensing element, a protection cover arranged in the accommodating cavity and located on the side of the fixed cover away from the water pressure sensing element, comprising a pressure compensation film, covering the through hole, in sealing connection with the fixed cover and at least partially flexible, a locking ring in sealing connection with the side of the pressure compensation film away from the fixed cover and in detachable connection with the shell, the pressure compensation film, the fixed cover and the sensing element cooperating to form a sealed cavity, the sealed cavity containing filling liquid, and the side of the pressure compensation film away from the sensing element being in contact with external water. The pressure type depth sensor can improve the durability and service life.

Description

Technical Field

[0001] This application relates to the field of underwater equipment, and in particular to a depth sensor. Background Technology

[0002] A depth sensor is a device specifically designed for underwater depth measurement. It is mainly used in underwater equipment such as submersible thrusters and underwater robots. For example, it measures the current water depth in real time and uses the depth data to adjust the thrust of the thruster or the angle of the control surface, and to ensure that the equipment is stable at the target depth.

[0003] Among them, pressure-type depth sensors are mainly suitable for deep-water environments with low visibility and complex obstacles. The principle is to use a water pressure sensing element to monitor water pressure. The pressure of the water being measured acts directly on the sensing element of the water pressure sensing element, causing the sensing element to deform in a way that is proportional to the water pressure. This causes a change in the electrical characteristic values ​​of the water pressure sensing element, such as resistance or capacitance. Electronic circuitry detects this change and converts it into a standard measurement signal corresponding to the pressure. Then, the water pressure is converted into underwater depth to obtain the underwater depth value.

[0004] Existing pressure-type depth sensors use sensing elements that directly contact the measured liquid to withstand pressure and deform, while also preventing liquid intrusion and protecting internal electronic components. However, deep water contains a large amount of silt and other impurities, which can interfere with the deformation of the sensing element. Furthermore, during underwater equipment movement, these impurities can easily collide with the sensing element. This not only leads to a significant decrease in sensor accuracy but can also, in severe cases, damage the sensing element, causing internal component failures and severely impacting the durability and lifespan of the pressure-type depth sensor. Utility Model Content

[0005] To improve the durability and service life of pressure-type depth sensors, this application provides a depth sensor.

[0006] The depth sensor provided in this application adopts the following technical solution: A depth sensor, comprising: The outer shell has a through-hole housing inside; A water pressure sensing element is disposed in the receiving cavity. The water pressure sensing element has a protruding sensing element in the middle. The sensing element has a head and a seat. The head is used to sense pressure deformation. A fixed cover is fixed in the receiving cavity. The fixed cover is sealed to the outer shell. The fixed cover has a through hole in the middle corresponding to the sensing element. The head is located in the through hole. The seat is sealed to the fixed cover. A protective cover, disposed within the receiving cavity and located on the side of the fixed cover away from the water pressure sensing element, includes: A pressure compensation membrane covering the through hole, the pressure compensation membrane being sealed to the fixed cover, the pressure compensation membrane being at least partially flexible; A locking ring is disposed on the side of the pressure compensation membrane facing away from the fixed cover. The locking ring is detachably connected to the outer shell and is sealed to the pressure compensation membrane. The pressure compensation membrane, the fixed cover, and the sensing element cooperate to form a sealed cavity, which contains a filling liquid. The side of the pressure compensation membrane facing away from the sensing element is in contact with external water.

[0007] By adopting the above scheme, the protective cover structure is equipped with a pressure compensation membrane and a locking ring, which cooperate with the fixed cover to form a sealed cavity and fill it with liquid. Pressure is transmitted through the pressure compensation membrane, and the incompressible filling liquid directly transmits the pressure to the sensing element, completely isolating the sensing element from external impurities and impacts. This achieves the dual function of physical isolation and pressure transmission, enabling the sensing element to monitor water pressure without direct contact with the outside. This avoids interference and damage to the depth sensor from underwater impurities, while accurately sensing pressure changes and improving the durability of the depth sensor. The pressure compensation membrane, filling liquid, and sensing element form a dynamic pressure balance system. The pressure compensation membrane uses a flexible material to cover the through holes, forming a variable volume cavity with the locking ring. The incompressibility of the filling liquid evenly transmits external water pressure to the sensing element. By coupling hydraulic transmission with elastic deformation, a triple pressure transmission mechanism is formed. When the sensor is subjected to severe pressure fluctuations such as underwater shock waves and rapid changes in depth, the flexible deformation of the membrane can instantly compensate for the pressure difference. Compared with traditional rigid structures, this reduces most of the peak stress impact and ensures the accuracy of pressure transmission. The protective cover structure uses only two parts, making it simple and reliable. The flexible pressure compensation membrane can prevent metal fatigue fracture caused by high-frequency pressure impacts such as water flow, and the multi-layer sealing structure improves durability and avoids sealing failure caused by temperature and pressure changes.

[0008] Preferably, the locking ring has a first flange at the edge of the fixing cover, and there is a gap between the first flange and the inner wall of the receiving cavity to form an annular groove. The pressure compensation membrane includes a sealing ring portion, which is disposed in the annular groove. The sealing ring portion is squeezed by the first flange, the inner wall of the receiving cavity, and the edge of the fixing cover.

[0009] By adopting the above scheme, the annular groove structure formed by the gap between the first flange and the cavity, combined with the elastic sealing ring of the pressure compensation membrane, constructs a three-dimensional spatial sealing system. During pressure fluctuations, the sealing ring is subjected to triaxial compression from axial locking force, radial cavity wall reaction force, and bottom fixed cover support force, forming an adaptive sealing interface. Compared to traditional planar seals, the contact stress distribution is more uniform, compensating for assembly tolerances and effectively preventing micro-leakage caused by vibration or temperature deformation. The combination of the annular groove and the detachable locking ring enables modular assembly of the sealing components. During maintenance, the pressure compensation membrane can be replaced without damage simply by unscrewing the locking ring, shortening the operation time compared to traditional potting sealing methods. Simultaneously, the groove structure physically limits the sealing ring, ensuring positional consistency during repeated assembly.

[0010] Preferably, the pressure compensation membrane includes a curved portion, the position of which corresponds to the position of the through hole, the curved portion is elastic, the center of the curved portion is recessed towards the through hole and has a distance from the port of the through hole.

[0011] By adopting the above scheme, the curved part is elastic, and the membrane can deform more flexibly when the pressure changes, thereby transmitting pressure better. The concave shape of the curved part forms a pre-set pressure buffer cavity, and the concave curved surface deflects the water flow impact direction, which can reduce the turbulence intensity and provide better dynamic response when the pressure fluctuates. At the same time, the existence of the gap may avoid the seal failure caused by temperature changes, liquid and material expansion or contraction, improve reliability, and reduce the risk of fatigue fracture.

[0012] Preferably, the inner wall of the locking ring is inclined, and the distance between the edge of the curved portion and the lower edge of the inclined surface of the inner peripheral wall of the locking ring is greater than 5 mm.

[0013] By adopting the above solution, the inclined inner wall facilitates alignment and positioning of the pressure compensation membrane during assembly, reducing friction or damage during installation. A spacing greater than 5 mm provides sufficient space for the pressure compensation membrane to deform under pressure, avoiding direct contact with the locking ring and thus reducing wear or stress concentration. Furthermore, the inclined surface design may improve pressure distribution, allowing pressure to be transmitted more evenly to the sealing ring, enhancing the sealing effect. Simultaneously, the inclined surface design forms a relatively large angle with the edge of the pressure compensation membrane, preventing foreign objects such as small underwater stones from getting stuck at the connection point and affecting pressure monitoring and membrane wear.

[0014] Preferably, a filter plate is provided near the pressure compensation membrane of the locking ring, and the filter plate has at least two filter holes with a diameter of 5 to 10 mm.

[0015] By adopting the above solution, a filter plate is installed in the locking ring, and the pore size is set to 5 to 10 mm. This can block larger impurities from entering while allowing water to flow through without affecting pressure transmission, thus effectively protecting the pressure compensation membrane.

[0016] Preferably, the locking ring is threadedly connected to the outer shell, and at least one pair of inner corner grooves are provided on the inner peripheral wall of the locking ring.

[0017] By adopting the above solution, the locking ring is connected to the housing via threads, making installation and disassembly more convenient and improving maintainability. The internal groove allows the locking ring to be rotated using a specific wrench, thereby enhancing the tightening force during assembly and preventing slippage. Furthermore, the threaded connection provides better sealing, especially in high-pressure underwater environments, where the threads can evenly distribute stress, reducing deformation or leakage caused by excessive local pressure. The internal groove also helps to transmit torque more evenly, preventing damage to the threads of the locking ring or housing during tightening, especially under frequent maintenance conditions.

[0018] Preferably, a first sealing ring is provided between the inner wall of the through hole and the seat, and the fixing cover extends a second flange from the edge adjacent to the through hole and the seat, wherein the inner edge of the second flange adjacent to the seat is a chamfered surface.

[0019] By adopting the above solution, the first sealing ring installed between the inner wall of the through hole and the seat can further enhance the sealing effect, prevent leakage of the filling fluid, and ensure the sealing performance of the sealing cavity. The second flange of the fixing cover is designed to extend, and its inner edge adjacent to the seat is chamfered. This design can guide the assembly, facilitating the installation of the seat and the fixing cover. At the same time, the chamfered surface can reduce stress concentration, prevent damage to the edge of the seat due to excessive stress, and improve the durability of the component.

[0020] Preferably, the outer casing has a threaded post extending from one end near the water pressure sensing element, the threaded post has a wire passage cavity in the middle, the wire of the water pressure sensing element passes through the wire passage cavity, and an open nut is fitted on the threaded post, the radial cross-section of the open nut being an arc shape.

[0021] By adopting the above scheme, a wire passage cavity is provided in the middle of the threaded post extending from the outer shell, providing a dedicated channel for the wires of the water pressure sensing element to pass through. This allows the wires to be led out of the sensor in an orderly manner, avoiding the tangled state of the wires inside the sensor and helping to improve the regularity of the sensor's internal structure. The wire passage cavity provides physical protection for the wires, preventing damage from external objects such as squeezing and friction during use, thereby extending the service life of the wires and ensuring the stability of the sensor's signal transmission. The open nut fitted on the threaded post has a radially curved cross-section. This structural design allows the open nut to be fitted directly onto the threaded post at a certain opening angle during installation, unlike ordinary nuts, and then tightened, simplifying the installation process and improving installation efficiency. When the sensor needs maintenance, repair, or component replacement, the open nut design also facilitates quick disassembly; simply loosening the nut is sufficient, which is more convenient than the traditional nut disassembly method, saving time and labor costs.

[0022] Preferably, the cavity containing the wire is filled with a filler that wraps around the wire of the water pressure sensing element.

[0023] By adopting the above solution, when using depth sensors in underwater environments, water can easily enter the sensor through the cable passage cavity. The filler can fill the gaps in the cable passage cavity, forming a sealed barrier that effectively prevents water intrusion. This avoids short circuits in the wires or damage to the water pressure sensing element caused by water intrusion, thereby ensuring the stability of the sensor's electrical performance and improving its reliability and durability in underwater environments. The filler can also firmly fix the wires inside the cable passage cavity, preventing the wires from shaking or shifting due to water flow impact, vibration, or other factors during sensor use. This avoids wear caused by friction between the wires and the inner wall of the cable passage cavity, reducing signal transmission failures due to wire damage and ensuring the accuracy and stability of sensor signal transmission.

[0024] In summary, this application has the following beneficial effects: 1. Physical isolation and dynamic pressure balance enhance anti-interference and durability. The sealed cavity formed by the pressure compensation membrane, fixed cover, and sensing element, along with the filling fluid, achieves complete physical isolation between the sensing element and the external water body. This effectively blocks direct impact and corrosion from underwater impurities and sediment, avoiding the failure problems of traditional sensors caused by impurity blockage or wear. The flexible pressure compensation membrane and incompressible filling fluid constitute a triple pressure transmission mechanism of hydraulic transmission and elastic deformation coupling. The flexible deformation of the pressure compensation membrane transmits pressure evenly to the filling fluid, enabling the sensing element to accurately sense pressure and respond instantly to severe pressure fluctuations such as underwater shock waves and sudden depth changes. The membrane's deformation absorbs peak stress, reducing instantaneous impact loads compared to rigid structures and significantly lowering the risk of fatigue fracture of the sensing element. The three-dimensional sealing system formed by the annular groove and the sealing ring automatically compensates for material deformation caused by assembly tolerances, temperature, and pressure fluctuations through axial, radial, and bottom three-way compressive stress distribution, preventing micro-leakage and ensuring long-term stable sealing within the normal underwater temperature and pressure fluctuation range.

[0025] 2. Optimized structural design enhances reliability and response accuracy. The curved section of the pressure compensation membrane is designed with a central recess and a pre-spacing structure to form a pre-set buffer cavity. On the one hand, the curved surface deflects the water flow, reducing turbulence interference; on the other hand, it provides the membrane with greater elastic deformation space, shortening the pressure response time and reducing linearity error, significantly superior to traditional planar membrane structures. The ≥5mm spacing between the inner bevel of the locking ring and the edge of the curved section avoids direct contact between the membrane and rigid components during deformation, reducing friction and wear. The chamfered bevel and the first sealing ring enhance the sealing performance between the seat and the fixed cover, while eliminating edge stress concentration and extending component life. The filter plate blocks larger particles from impacting the pressure compensation membrane while allowing unobstructed water flow, ensuring pressure transmission without delay, balancing protection and signal sensitivity.

[0026] 3. Modular design and convenient maintenance reduce operating costs. The threaded connection between the locking ring and the outer shell, combined with the internal groove design, supports quick disassembly using tools. Compared with the traditional method of replacing the entire seal with glue, maintenance efficiency is improved, and it can be reassembled without affecting the sealing performance. The threaded post through the wire cavity combined with the filler design provides an independent channel for the wire to avoid entanglement and damage, and the filler seals and isolates moisture to prevent sensor failure caused by wire short circuits, which is especially suitable for long-term underwater operation environments.

[0027] This application overcomes the problems of traditional depth sensors being susceptible to interference from impurities, having poor impact resistance, and being difficult to maintain through a systematic design that includes sealed isolation, dynamic compensation, structural reinforcement, and convenient maintenance, thereby improving durability, reliability, and measurement accuracy. Attached Figure Description

[0028] Figure 1This is a three-dimensional structural schematic diagram of Embodiment 1 of this application; Figure 2 This is a cross-sectional structural diagram of Embodiment 1 of this application; Figure 3 This is a three-dimensional structural schematic diagram of the outer shell of Embodiment 1 of this application; Figure 4 This is a cross-sectional structural diagram of the outer shell of Embodiment 1 of this application; Figure 5 This is a three-dimensional structural schematic diagram of the water pressure sensing element of Embodiment 1 of this application; Figure 6 This is a cross-sectional structural diagram of the fixing cover of Embodiment 1 of this application; Figure 7 This is a three-dimensional structural schematic diagram of the pressure compensation membrane in Embodiment 1 of this application; Figure 8 This is a cross-sectional structural schematic diagram of the pressure compensation membrane in Embodiment 1 of this application; Figure 9 This is a three-dimensional structural schematic diagram of the locking ring of Embodiment 1 of this application; Figure 10 This is a cross-sectional structural diagram of the locking ring of Embodiment 1 of this application; Figure 11 This is a cross-sectional structural diagram of Embodiment 2 of this application.

[0029] Explanation of reference numerals in the attached drawings: 1. Outer shell; 11. Receiving cavity; 2. Water pressure sensing element; 21. Sensing element; 211. Head; 212. Seat; 22. Circuit board; 3. Fixing cover; 31. Through hole; 32. First sealing ring; 33. Second flange; 34. Chamfered bevel; 4. Protective cover; 41. Pressure compensation membrane; 411. Sealing ring part; 412. Bend part; 42. Locking ring; 421. Sealing cavity; 422. First flange; 423. Annular groove; 424. Inner corner groove; 425. Inclined surface; 5. Threaded post; 6. Cable passage cavity; 7. Filler; 8. Open nut; 9. Filter plate. Detailed Implementation

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] In this invention, 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 part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0034] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0035] The following is in conjunction with the appendix Figure 1-11 This application will be described in further detail.

[0036] Example 1 Reference Figure 1 as well as Figure 2 A depth sensor includes a housing 1, a water pressure sensing element 2, a fixing cover 3, and a protective cover 4.

[0037] like Figure 2As shown, the outer shell 1 is cylindrical in shape, and the interior of the outer shell 1 has a through-hole receiving cavity 11.

[0038] like Figures 3 to 5 As shown, the water pressure sensing element 2 includes a sensing element 21 and a circuit board 22. The inner wall of the receiving cavity 11 inside the housing 1 is designed with a stepped surface, and the circuit board 22 is mounted on this stepped surface. The sensing element 21 is mounted on the circuit board 22, and the sensing element 21 is located on the middle surface of the circuit board 22 in a raised shape. The sensing element 21 has a head 211 and a seat 212. The head 211 is used to sense pressure deformation, and the seat 212 is electrically connected to the circuit board 22.

[0039] like Figure 2 as well as Figure 6 As shown, the fixing cover 3 is a circular plate that matches the inner diameter of the receiving cavity 11, and the fixing cover 3 is disposed inside the receiving cavity 11. The fixing cover 3 is sealed to the outer shell 1, and the fixing cover 3 has a through hole 31 in the middle corresponding to the sensing element 21. The head 211 is located in the through hole 31, and the seat 212 is sealed to the lower edge of the through hole 31. Specifically, a first sealing ring 32 is provided between the inner wall of the through hole 31 and the seat 212. The fixing cover 3 has a second flange 33 extending from the edge adjacent to the through hole 31 and the seat 212. The inner edge of the second flange 33 adjacent to the seat 212 is a chamfered bevel 34. The second flange 33 presses against the seat 212 and cooperates with the stepped surface below the circuit board 22 to fix the water pressure sensing element 2 in the receiving cavity 11.

[0040] like Figure 2 , Figure 7 as well as Figure 8As shown, the protective cover 4 is disposed within the receiving cavity 11 and is located on the side of the fixed cover 3 away from the water pressure sensing element 2. The protective cover 4 includes a pressure compensation membrane 41 and a locking ring 42. The pressure compensation membrane 41 is circular in shape and is an elastic flexible membrane. The outer ring of the pressure compensation membrane 41 is configured as a sealing ring portion 411, and the middle portion is configured as a curved portion 412. The lower surface of the sealing ring portion 411 of the pressure compensation membrane 41 contacts the edge of the upper surface of the fixed cover 3, and the contact surface is in a sealed state. The pressure compensation membrane 41 covers the through hole 31, and the curved portion 412 in its middle corresponds to the through hole 31 of the fixed cover 3. The center of the curved portion 412 is recessed towards the through hole 31, that is, the cross-sectional shape of the curved portion 412 is corrugated. The center of the bent portion 412 is spaced from the port of the through hole 31, meaning there is also a certain space between the bent portion 412 and the upper surface of the fixed cover 3. This space communicates with the internal space of the through hole 31 to form a cavity. The through hole 31 and the sensing element 21 are sealed and isolated by the first sealing ring 32, thus making this cavity a sealed cavity 421, ensuring pressure transmission while preventing the circuit board 22 from contacting liquid. The side of the pressure compensation membrane 41 facing away from the sensing element 21 is in contact with external water. The sealed cavity 421 is filled with a filling liquid, which is used to transmit the pressure received by the bent portion 412 to the sensing element 21, enabling the sensing element 21 to detect external water pressure. The filling liquid can be insulating oil; most preferably, pure water is used, which can transmit pressure without causing additional ionic corrosion damage to the sensing element 21.

[0041] Among them, such as Figure 2 , Figure 9 as well as Figure 10 As shown, the locking ring 42 is cylindrical and is located on the side of the pressure compensation membrane 41 facing away from the fixed cover 3, i.e., the fixed cover 3 and the locking ring 42 are located on opposite sides of the pressure compensation membrane 41. The locking ring 42 is detachably connected to the outer shell 1. Specifically, the outer circumferential surface of the locking ring 42 is threaded, and the inner ring of the outer shell 1 is threaded, and the locking ring 42 is threaded to the outer shell 1. This connection method allows the locking ring 42 to be easily removed. The locking ring 42 is sealed to the pressure compensation membrane 41. Specifically, the locking ring 42 has a first flange 422 at the edge of the fixed cover 3, and there is a gap between the first flange 422 and the inner wall of the sealed cavity 11 to form an annular groove 423. The sealing ring portion 411 of the pressure compensation membrane 41 is located in the annular groove 423. The sealing ring portion 411 is compressed by the first flange 422, the inner wall of the receiving cavity 11, and the edge of the fixing cover 3 to form a three-dimensional spatial sealing system. At the same time, the groove structure of the annular groove 423 provides physical limitation for the sealing ring portion 411. At least one pair of inner corner grooves 424 are provided on the inner peripheral wall of the locking ring 42. The inner corner grooves 424 allow the locking ring 42 to be rotated using a specific wrench, thereby enhancing the tightening force during assembly.

[0042] like Figure 2 As shown, the outer casing 1 extends from the end of the water pressure sensing element 2 away from the protective cover 4, with a threaded post 5. The threaded post 5 has a wire passage cavity 6 in the middle, providing a dedicated passage for the wires of the water pressure sensing element 2. The wires of the water pressure sensing element 21 pass through the wire passage cavity 6. A filler 7 is provided in the wire passage cavity 6, formed by injecting glue into the wire passage cavity 6 after the wires pass through, thus encapsulating the wires of the water pressure sensing element 21. An open nut 8 is fitted onto the threaded post 5, and the radial cross-section of the open nut 8 is arc-shaped.

[0043] The implementation principle of a depth sensor according to an embodiment of this application is as follows: A protective cover 4 is located on the side of the fixed cover 3 away from the water pressure sensing element 2. The pressure compensation membrane 41 is a circular flexible elastic membrane with an outer sealing ring 411 and a curved portion 412 in the middle. The lower surface of the sealing ring 411 contacts and seals the edge of the fixed cover 3, covering the through hole 31. The center of the curved portion 412 is recessed towards the through hole 31 in an annular corrugated shape, forming a space with the surface of the fixed cover 3 and communicating with the interior of the through hole 31 to form a sealed cavity 421. The sealed cavity 421 is filled with a filling liquid. The side of the pressure compensation membrane 41 facing away from the sensing element 21 contacts the external water body. The pressure received by the curved portion 412 is transmitted to the sensing element 21 through the filling liquid, thereby detecting the external water pressure.

[0044] The depth sensor in this application embodiment is mainly used in underwater equipment such as underwater thrusters or underwater robots. The threaded post 5 is passed through the hull wall of the underwater equipment, and a sealing O-ring is fitted on the threaded post 5 to achieve a seal. It is locked and fixed by the open nut 8. The wire is connected to the central controller inside the hull.

[0045] The embodiments of this application have the effect of improving the durability and service life of pressure-type depth sensors.

[0046] Example 2 A depth sensor, the difference between this embodiment and Embodiment 1 is that: Figure 11As shown, the inner wall of the locking ring 42 is inclined, specifically, the inner circumferential surface at least at the first flange 422 is inclined 425. This inclined surface 425 forms an obtuse angle with the surface of the pressure compensation membrane 41 adjacent to the inclined surface 425, thereby preventing foreign objects such as sand and gravel from getting stuck at the edge joint and putting pressure on the pressure compensation membrane 41. The distance between the edge of the curved portion 412 and the lower edge of the inclined surface of the inner circumferential wall of the locking ring 42 is greater than 5 mm. This distance is larger than the size of most hard objects such as sand and gravel that can float with the water flow underwater, further preventing sand and gravel from getting stuck. Moreover, the distance of more than 5 mm provides sufficient space for the pressure compensation membrane 41 to deform under pressure, avoiding direct contact with the locking ring 42, thereby reducing wear or stress concentration. When the pressure fluctuates, the sealing ring portion 411 is subjected to three-way compression from the axial locking force, the radial cavity wall reaction force, and the support force of the bottom fixed cover 3, forming an adaptive sealing interface. A filter plate 9 is located near the pressure compensation membrane 41 on the locking ring 42. The filter plate 9 has several filter holes that are evenly distributed radially. The diameter of the holes on the filter plate 9 is designed to be 5 to 10 mm. This size can block larger impurities from entering while allowing water to flow through without affecting pressure transmission.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A depth sensor, characterized in that, include: The outer shell (1) has a through-hole (11) inside; A water pressure sensing element (2) is fixed inside the receiving cavity (11). The water pressure sensing element (2) has a protruding sensing element (21) in the middle. The sensing element (21) has a head (211) and a seat (212). The head (211) is used to sense pressure deformation. A fixed cover (3) is disposed in the receiving cavity (11). The fixed cover (3) is sealed to the outer shell (1). The fixed cover (3) has a through hole (31) in the middle corresponding to the sensing element (21). The head (211) is located in the through hole (31). The seat (212) is sealed to the fixed cover (3). A protective cover (4), disposed within the receiving cavity (11) and located on the side of the fixed cover (3) away from the water pressure sensing element (2), comprises: A pressure compensation membrane (41) covering the through hole (31) is sealed to the fixing cover (3), and the pressure compensation membrane (41) is at least partially flexible. A locking ring (42) is disposed on the side of the pressure compensation membrane (41) facing away from the fixed cover (3). The locking ring (42) is detachably connected to the outer shell (1) and is sealed to the pressure compensation membrane (41). The pressure compensation membrane (41), the fixing cover (3), and the sensing element (21) cooperate to form a sealed cavity (421), which contains a filling liquid. The side of the pressure compensation membrane (41) facing away from the sensing element (21) is in contact with external water.

2. A depth sensor according to claim 1, characterized in that, The locking ring (42) is provided with a first flange (422) at the edge of the fixing cover (3). The first flange (422) has a gap with the inner wall of the receiving cavity (11) to form an annular groove (423). The pressure compensation membrane (41) includes a sealing ring part (411), which is disposed in the annular groove (423).

3. A depth sensor according to claim 1, characterized in that, The pressure compensation membrane (41) includes a curved portion (412) whose position corresponds to the position of the through hole (31). The curved portion (412) is elastic, and the center of the curved portion (412) is recessed toward the through hole (31) and has a gap with the port of the through hole (31).

4. A depth sensor according to claim 3, characterized in that, The inner wall of the locking ring (42) is inclined (425), and the distance between the edge of the bent portion (412) and the lower edge of the inclined surface (425) of the inner peripheral wall of the locking ring (42) is greater than 5 mm.

5. A depth sensor according to claim 4, characterized in that, A filter plate (9) is provided near the pressure compensation membrane (41) on the locking ring (42). The filter plate (9) has at least two filter holes with a diameter of 5 to 10 mm.

6. A depth sensor according to claim 1, characterized in that, The locking ring (42) is threadedly connected to the outer shell (1), and at least one pair of inner corner grooves (424) are provided on the inner peripheral wall of the locking ring (42).

7. A depth sensor according to claim 1, characterized in that, A first sealing ring (32) is provided between the inner wall of the through hole (31) and the seat (212). The fixing cover (3) extends a second flange (33) on the edge adjacent to the through hole (31) and the seat (212). The inner edge of the second flange (33) adjacent to the seat (212) is a chamfered bevel (34).

8. A depth sensor according to claim 1, characterized in that, The outer casing (1) extends a threaded post (5) at the end of the water pressure sensing element (2) away from the protective cover (4). The threaded post (5) has a wire passage cavity (6) in the middle. The wire of the water pressure sensing element (21) passes through the wire passage cavity (6). An open nut (8) is fitted on the threaded post (5). The radial cross section of the open nut (8) is arc-shaped.

9. A depth sensor according to claim 8, characterized in that, A filler (7) is provided in the wire cavity (6), and the filler (7) wraps the wire of the water pressure sensing element (21).

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