Impact speed mechanical sensor applied to severe environment

Abstract

The invention relates to an impact speed mechanical sensor applied to a severe environment, and relates to the field of sensors, the impact speed mechanical sensor comprises a shell, an upper cover plate, an inner core and a force sensor, the force sensor is placed at the bottom of the shell, and a plurality of groups of square strips which are different in length and made of super-viscoelastic and super-elastic materials are arranged in the inner core at intervals; the inner core is placed on the force sensor, the upper cover plate is placed on the inner core and is in sliding connection with the shell, and the device has the advantages that impact signals can be converted into visual information or force signals only through a mechanical structure, and the device can be widely applied to impact monitoring scenes with high requirements for reliability and environmental adaptability.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to an impact velocity mechanical sensor for use in harsh environments. Background Technology

[0002] Existing impact velocity sensors mostly rely on indirect sensing by monitoring acceleration signals. For example, automobiles use high-precision electronic impact acceleration sensors to capture acceleration changes during impact events such as collisions and bumps. The ECU (Electronic Control Unit) then integrates the acceleration signals to indirectly obtain the velocity change during the impact. Determining impact velocity after an accident also largely depends on onboard data recording equipment. However, if the accident causes equipment malfunction, it becomes difficult to determine the vehicle's speed at the time of the accident.

[0003] Currently, common impact velocity sensors mainly include piezoelectric impact velocity sensors, photoelectric impact velocity sensors, Hall effect impact velocity sensors, and strain gauge impact velocity sensors. These sensors have relatively complex structures, including sensitive elements (such as piezoelectric crystals, laser modules, etc.), signal processing, etc., making them difficult to maintain independently; they are also expensive, costing thousands to tens of thousands of yuan. The barrier to entry for their use is also high, requiring certain professional knowledge, and more importantly, not all of them are suitable for complex and harsh environments.

[0004] Therefore, to address the above shortcomings, there is a need to provide an impact velocity mechanical sensor for use in harsh environments. Summary of the Invention

[0005] (a) Technical problems to be solved The technical problem to be solved by this invention is how to make the structure of the impact sensor simpler and more durable while ensuring the detection accuracy of the impact sensor.

[0006] (II) Technical Solution To address the aforementioned technical problems, this invention provides an impact velocity mechanical sensor applicable in harsh environments, comprising a housing, a top cover, an inner core, and a force sensor. The force sensor is placed at the bottom of the housing. The inner core contains several sets of square strips of different lengths made of supervisoelastic and superelastic materials. The inner core is placed on the force sensor, and the top cover is placed on the inner core and slidably connected to the housing.

[0007] As a further explanation of the present invention, preferably, the inner core includes a ladder platform, a strain rate sensitive beam and a base. The strain rate sensitive beam is a double-layer square strip structure. The double-layer distribution direction of the strain rate sensitive beam is horizontal, and the length direction of the strain rate sensitive beam is vertical. The two ends of the strain rate sensitive beam in the length direction are respectively fixed to the ladder platform and the base. The base abuts against the force sensor, and the ladder platform abuts against the upper cover plate.

[0008] As a further explanation of the present invention, preferably, the strain rate sensitive beams are all made of the same material in a single layer, and adjacent strain rate sensitive beams are arranged in a mirror image.

[0009] As a further explanation of the present invention, preferably, the platform or the platform and the base are both stepped structures, and each step has two sets of strain rate sensitive beams.

[0010] As a further explanation of the present invention, preferably, an observation window is provided on the front end face of the outer shell, the length of the observation window is greater than the distribution length of the inner core, and a transparent glass is fixedly connected to the observation window.

[0011] As a further explanation of the present invention, preferably, a plurality of slots are provided on the left and right side walls of the inner cavity of the outer shell along the vertical direction, and buckles are fixedly connected to the lower left and right sides of the bottom of the upper cover plate, and the upper cover plate is moved down so that the buckles are engaged in different slots.

[0012] As a further explanation of the present invention, preferably, a square boss is fixedly connected to the middle of the bottom end of the upper cover plate. The outer diameter of the boss is smaller than the inner diameter of the opening at the top of the outer shell, and the height of the boss is greater than the buckle length so as to abut against the inner core.

[0013] As a further explanation of the present invention, preferably, a signal output port is provided on one side of the bottom of the housing so that the force sensor cable extends out of the housing.

[0014] (III) Beneficial Effects The above-described technical solution of the present invention has the following advantages: This invention is based on the principle of mechanical deformation, achieving impact velocity detection without additional structures. Its simple structure and significantly lower manufacturing cost compared to traditional impact velocity sensors result in accurate measurements. Furthermore, its core components are durable mechanical structures, eliminating electronic faults such as capacitor leakage, chip burnout, and poor circuit contact. With normal maintenance, its lifespan can reach decades. It boasts strong overload resistance, requires no power supply, and is independent of electrical energy, avoiding sensing interruptions caused by power outages or voltage fluctuations. This makes it suitable for field and emergency scenarios. Even if a fault occurs, it is mostly due to mechanical wear, i.e., damage to the inner core. Repair requires no specialized electronic knowledge; only the inner core needs to be replaced. The principle is intuitive, requiring no electronic processing; ordinary people can troubleshoot problems by observing the structure. Attached Figure Description

[0015] Figure 1 This is an assembly effect diagram of the present invention; Figure 2 This is an exploded view of the structure of the present invention; Figure 3 This is a diagram of the inner core structure of the present invention; Figure 4 This is a loading effect diagram of the present invention; Figure 5 This is a load-displacement curve diagram of the structure under different loading speeds according to the present invention; Figure 6 This is a graph showing the relationship between the wall thickness ratio and the critical strain rate of the present invention; Figure 7 This is a graph showing the relationship between the thickness ratio of the two materials and the critical strain rate in this invention. Figure 8 This is a graph showing the relationship between the slenderness ratio and the critical strain rate of the present invention.

[0016] In the diagram: 1. Outer shell; 11. Observation window; 12. Signal output port; 13. Slot; 2. Top cover plate; 21. Buckle; 3. Inner core; 31. Ladder platform; 32. Strain rate sensitive beam; 33. Base; 4. Force sensor. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] An impact velocity mechanical sensor for use in harsh environments, combined with Figure 1 , Figure 2 It includes a housing 1, a top cover 2, an inner core 3, and a force sensor 4. The force sensor 4 is placed at the bottom of the housing 1, the inner core 3 is placed on the force sensor 4, and the top cover 2 is placed on the inner core 3 and is slidably connected to the housing 1.

[0019] Combination Figure 1 , Figure 2 The outer shell 1 is a square shell, but it can also be other polygonal structures or a circular shell. The outer shell 1 has a cavity in the middle and an open top. An observation window 11 is opened on the front end face of the outer shell 1. The length of the observation window 11 is greater than the distribution length of the inner core 3. A transparent glass is fixed to the observation window 11 to allow direct observation of the changes of the inner core 3 under load. A signal output port 12 is opened on one side of the bottom of the outer shell 1 so that the cable of the force sensor 4 can extend out of the outer shell 1, so that the sensor can transmit signals outward.

[0020] Combination Figure 1 , Figure 2The upper cover plate 2 is a square or circular plate structure. A square boss is fixed to the center of the bottom of the upper cover plate 2, and the outer diameter of the boss is smaller than the inner diameter of the top opening of the outer shell 1. L-shaped buckles 21 are fixed to the lower left and right sides of the bottom of the upper cover plate 2. Several triangular slots 13 are spaced vertically on the left and right side walls of the inner cavity of the outer shell 1. The upper cover plate 2 moves down so that the buckles 21 can be engaged in different slots 13. The height of the boss is greater than the length of the buckle 21 so as to abut against the inner core 3. The slots 13 are provided on the outer shell 1 to ensure a stable connection between the upper cover plate 2 and the outer shell 1 and to prevent the upper cover plate 2 from detaching from the outer shell 1. In addition, multiple slots 13 are provided to accommodate inner cores 3 of different heights inside the outer shell 1, so that the outer shell 1 can measure impact velocities of different ranges according to the customer's needs. Standardized production can meet the customized requirements of different customers and significantly reduce production costs.

[0021] Combination Figure 2 , Figure 3 The inner core 3 includes a stepped platform 31, a strain rate sensitive beam 32, and a base 33. The base 33 is preferably a flat plate structure, and the stepped platform 31 is a stepped plate structure. Alternatively, both the base 33 and the stepped platform 31 can be stepped structures. Each step has two sets of strain rate sensitive beams 32, ensuring that the lengths of the strain rate sensitive beams 32 differ between steps, with the lengths decreasing or increasing gradually in one direction. The strain rate sensitive beam 32 is a double-layered square strip structure, with each layer being a sheet structure made of two different materials. One layer is made of a viscoelastic material, which combines high deformability and high strain rate dependence; specifically, it can be made of 70-degree silicone rubber. The other layer is made of a hyperelastic material, which has high deformability but is essentially independent of strain rate; specifically, it can be made of 70-degree styrene-butadiene rubber. When subjected to a sufficiently large compressive force along its length, this double-layered structure buckles to the left or right as expected. The rate of buckling (strain) depends on the beam's dimensions, such as slenderness ratio, width-to-thickness ratio, and the proportions of the two materials; different dimensions correspond to different buckling strain rates. Specifically: in, This represents the critical buckling strain of the viscoelastic layer. The critical buckling strain of the hyperelastic layer; These are the initial hyperelastic constitutive parameters of the visco-hyperelastic layer; The hyperelastic constitutive parameters of the hyperelastic layer; It is the viscoelastic relaxation coefficient; For time; This refers to the viscoelastic relaxation time. The thickness of the viscoelastic layer; The thickness of the superelastic layer; The width of strain rate sensitive beam 32; Let be the length of the strain rate sensitive beam 32.

[0022] The formula shows that the buckling strain is related to length, thickness, width, material properties, and time. The critical strain rate for buckling towards the viscohyperelastic side can be derived from the strains of the two separate buckling sections. The theoretical solution is as follows: Figures 6-8 As shown. Combined with Figure 3 The inner core 3 structure shown has a strain rate sensitive beam 32 with a slenderness ratio decreasing from left to right. The higher the slenderness ratio, the higher the buckling speed required towards the viscoelastic side (inward contraction), which aligns with... Figure 8 The trend of the relationship between the slenderness ratio and the strain rate indicates that the overall trend of the theoretical solution is roughly correct.

[0023] Combination Figure 2 , Figure 3 The strain rate sensitive beam 32 is distributed in a horizontal double-layer configuration, with its length direction being vertical. Both ends of the strain rate sensitive beam 32 along its length are fixed to a platform 31 and a base 33, respectively. The base 33 abuts against the force sensor 4, and the platform 31 abuts against the protrusion of the upper cover plate 2. The dual-material strain rate sensitive beam 32 has different bidirectional buckling critical strain rates under different slenderness ratios, width-to-thickness ratios, and material ratios. That is, beams of different sizes buckle in different directions at different speeds. By placing strain rate sensitive beams 32 of different sizes in the inner core 3 and adjusting the beam element parameters according to the expected impact speed range, the impact speed can be determined by the buckling direction of different beams in the inner core 3.

[0024] The double-layer structure on the strain rate sensitive beam 32 can be arranged sequentially or as mirror images of adjacent strain rate sensitive beams 32. Figure 2 Arranged in order, Figure 3 The diagram shows a mirror-image arrangement. Taking the mirror-image arrangement as an example, experiments were conducted on the inner core 3 under the same load but different loading times. Because the latch 21 of the upper cover plate 2 engages with the slot 13 of the outer shell 1 after impact, the inner core 3 remains in a buckled state. The beam buckling condition can be observed through the transparent observation window 11 after impact, thus obtaining the impact velocity of the structure. The buckling results of the inner core 3 are shown below. Figure 4 As shown. Simultaneously obtain as... Figure 5 The displacement curves of the structure under different loading rates are shown.

[0025] Due to the mirror arrangement of strain rate sensitive beams 32, there is a 2-3 times difference in the structural strength of the beam unit cell under bidirectional buckling. At this time, the inward high strength can be regarded as the "1" state and the outward low strength as the "0" state. The load signal is collected by force sensor 4, and the impact velocity signal is converted into a force response signal to obtain the impact velocity.

[0026] In summary, this invention, based on the principle of mechanical deformation, achieves impact velocity detection without the need for additional structures. Its simple structure results in significantly lower manufacturing and maintenance costs compared to traditional impact velocity sensors. Even if inaccurate detection or core damage occurs, users can easily replace it themselves, making it extremely user-friendly. Furthermore, it can be used in environments without power, demonstrating high adaptability to harsh conditions. More importantly, it maintains the core 3 in a deformed state after impact, thanks to the restraints of the latch 21 and slot 13, preventing data loss.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An impact velocity mechanical sensor for use in harsh environments, characterized in that: It includes an outer shell (1), a top cover plate (2), an inner core (3) and a force sensor (4). The force sensor (4) is placed at the bottom of the outer shell (1). The inner core (3) is provided with several sets of square strips of different lengths made of supervisoelastic and superelastic materials. The inner core (3) is placed on the force sensor (4). The top cover plate (2) is placed on the inner core (3) and is slidably connected to the outer shell (1).

2. The impact velocity mechanical sensor for use in harsh environments according to claim 1, characterized in that: The inner core (3) includes a ladder (31), a strain rate sensitive beam (32) and a base (33). The strain rate sensitive beam (32) is a double-layer square strip structure. The double-layer distribution direction of the strain rate sensitive beam (32) is horizontal, and the length direction of the strain rate sensitive beam (32) is vertical. The two ends of the length direction of the strain rate sensitive beam (32) are fixedly connected to the ladder (31) and the base (33) respectively. The base (33) abuts against the force sensor (4), and the ladder (31) abuts against the upper cover plate (2).

3. The impact velocity mechanical sensor for use in harsh environments according to claim 2, characterized in that: The strain rate sensitive beams (32) are all made of the same material in a single layer, and adjacent strain rate sensitive beams (32) are arranged in a mirror image.

4. The impact velocity mechanical sensor for use in harsh environments according to claim 3, characterized in that: The platform (31) or platform (31) and base (33) are both stepped structures, and each step has two sets of strain rate sensitive beams (32).

5. The impact velocity mechanical sensor for use in harsh environments according to claim 1, characterized in that: An observation window (11) is provided on the front end of the outer shell (1). The length of the observation window (11) is greater than the distribution length of the inner core (3). A transparent glass is fixed at the observation window (11).

6. The impact velocity mechanical sensor for use in harsh environments according to claim 1, characterized in that: The inner walls of the outer shell (1) are provided with several slots (13) spaced vertically on the left and right sides. The bottom left and right sides of the upper cover plate (2) are fixed with buckles (21). The upper cover plate (2) is moved down so that the buckles (21) can be inserted into different slots (13).

7. The impact velocity mechanical sensor for use in harsh environments according to claim 6, characterized in that: A square boss is fixed to the middle of the bottom end of the top cover plate (2). The outer diameter of the boss is smaller than the inner diameter of the top opening of the outer shell (1). The height of the boss is greater than the length of the buckle (21) so as to abut against the inner core (3).

8. The impact velocity mechanical sensor for use in harsh environments according to claim 1, characterized in that: A signal output port (12) is provided on one side of the bottom of the housing (1) so that the cable of the force sensor (4) extends out of the housing (1).

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