Self-powered vehicle sensing device

Abstract

The invention provides a self-powered vehicle sensing device. The self-powered vehicle sensing device comprises a base, a top plate and two triboelectric units. The base is used for being embedded and fixed on a detected road surface. The top plate is slidably connected to the base in the vehicle passing direction and is flush with the detected road surface. The two friction electricity units are symmetrically connected to the two ends of the base and connected with the top plate. Each of the two friction power units comprises a friction power generation module and a switch module electrically connected to the friction power generation module; the top plate is used for performing translational motion under the driving of wheel friction, the two friction power generation modules are used for performing friction power generation under the driving of the translational motion of the top plate, and the two switch modules are closed successively under the driving of the translational motion of the top plate to trigger switch signals respectively; wherein the trigger time difference and the travel difference of the two switching signals are used for feeding back the speed and the acceleration of the vehicle. According to the self-powered vehicle sensing device provided by the invention, integration of energy collection and speed sensing functions can be realized, and the energy conversion rate and the vehicle passing stability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of information sensing, and particularly relates to a self-powered vehicle sensing device. Background Art

[0002] For the safe and efficient operation of the road traffic system, it is necessary to monitor, collect and process road traffic information such as vehicle speed and motion state in real time. Speed and acceleration sensors installed on the road can provide real-time and reliable data for the traffic system. On the one hand, it is beneficial to reduce the occurrence of traffic accidents, and on the other hand, it can provide information for the responsibility division and traceability of traffic accidents. However, for widely distributed sensors, how to provide sustainable energy for them is an urgent problem to be solved.

[0003] Currently, the energy harvesting scheme of the traffic sensing system mostly uses energy harvesting speed bumps, and the vibration energy generated when the vehicle passes over the speed bump is used to excite the piezoelectric material to generate electric energy. However, this energy harvesting method is difficult to be integrally loaded with the sensing unit due to vibration shock problems, and there are also problems such as low electromechanical conversion efficiency and large impact on passing vehicles. Therefore, it is urgent to develop a new solution to overcome the above problems. Summary of the Invention

[0004] An embodiment of the present invention provides a self-powered vehicle sensing device, aiming to realize the integration of energy harvesting and speed sensing functions, and improve the electromechanical conversion efficiency and vehicle passing smoothness.

[0005] To achieve the above object, the technical solution adopted by the present invention is: providing a self-powered vehicle sensing device, including a base, a top plate and two triboelectric units; the base is used for being embedded and fixed on the measured road surface, the top plate is slidably connected to the base along the vehicle passing direction and is flush with the measured road surface; the two triboelectric units are symmetrically connected to both ends of the base and are both connected to the top plate; the two triboelectric units both include a triboelectric power generation module and a switch module electrically connected to the triboelectric power generation module; the top plate is used for translating under the friction drive of the wheel, the two triboelectric power generation modules are used for triboelectric power generation under the drive of the translation movement of the top plate, and the two switch modules are sequentially closed under the drive of the translation movement of the top plate to respectively trigger switch signals; wherein, the time difference and travel difference triggered by the two switch signals are used to feedback the speed and acceleration of the vehicle.

[0006] In a possible implementation manner, the switch module includes a movable electrode and two fixed electrodes; the movable electrode is connected to the triboelectric power generation module and translates together with the top plate, the two fixed electrodes are respectively fixed on both sides of the movable electrode and are both connected and conducted with the triboelectric power generation module; wherein, the initial distances between the movable electrode and the two fixed electrodes are different, and a switch signal is triggered when the movable electrode comes into contact and conducts with any one of the fixed electrodes.

[0007] In some embodiments, the triboelectric power generation module includes a number of triboelectric electrodes that are sequentially connected to form an elastic folding structure. One end of the elastic folding structure is fixedly connected to the base, and the other end is connected to the top plate. One end of each triboelectric electrode is connected and conducted with the movable electrode, and the other end is connected and conducted with two fixed electrodes. Each triboelectric electrode is used for triboelectric power generation driven by the translational movement of the top plate.

[0008] Exemplarily, the self-powered vehicle sensing device further includes an energy conversion and collection mechanism and a control circuit board. The control circuit board is electrically connected to the two triboelectric units respectively and is used for receiving switch signals. A power storage element is provided on the control circuit board. The energy conversion and collection mechanism includes an energy collection component and an energy conversion component. The energy collection component is connected to the center of the base, and the energy conversion component is connected to the top plate and is in transmission connection with the energy collection component. Among them, the energy conversion component is used for converting the translational movement energy of the top plate into rotational mechanical energy and transmitting it to the energy collection component. The energy collection component is electrically connected to the control circuit board and is used for converting the rotational mechanical energy into electrical energy and storing it in the power storage element.

[0009] For example, the energy conversion component includes a rack, an input gear, an intermediate gear set, and an output gear. The rack is fixedly connected to the top plate along the vehicle passing direction. The input gear is rotatably connected to the base and meshes with the rack. The output gear is connected to the energy collection component and is in transmission connection with the input gear through the intermediate gear set. Among them, the intermediate gear set is used for converting the bidirectional rotational movement of the input gear into the unidirectional rotational movement of the output gear.

[0010] In a possible implementation manner, the intermediate gear set includes a first gear, a second gear, a third gear, a fourth gear, and a reversing gear that are rotatably connected to the base. The first gear meshes with the input gear and is connected to the third gear through a first one-way bearing. The reversing gear meshes with the input gear. The second gear meshes with the reversing gear and is connected to the fourth gear through a second one-way bearing. Both the third gear and the fourth gear mesh with the output gear.

[0011] In some embodiments, a support housing is fixedly connected to the base. The input gear, the first gear, the second gear, and the reversing gear are all rotatably connected to the outer top wall of the support housing. The output gear, the third gear, the fourth gear, and the energy collection component are all arranged inside the support housing.

[0012] Exemplarily, a first one-way bearing is embedded in the center of the third gear, and a second one-way bearing is embedded in the center of the fourth gear. The first gear is provided with a first central shaft, and the first central shaft rotatably passes through the support housing and is connected to the first one-way bearing. The second gear is provided with a second central shaft, and the second central shaft rotatably passes through the support housing and is connected to the second one-way bearing.

[0013] For example, the energy collection component includes a disk and a plurality of coils; the coils are distributed in a circular array at the center of the base, the disk is rotatably connected to the base and corresponds to each coil up and down, and the disk is fixedly connected to the output gear.

[0014] In some embodiments, two guide rails are arranged on the base in parallel and at intervals, and the guide rails extend along the direction of vehicle travel. A sliding seat is slidably connected to each guide rail, and the top plate is fixedly connected to each sliding seat.

[0015] The beneficial effect of the self-powered vehicle sensing device provided by the present invention is that compared with the prior art, the self-powered vehicle sensing device of the present invention, when the vehicle passes through the top plate, the wheels rub the top plate and drive the top plate to translate relative to the base, thereby being able to provide energy to the two friction electric units through the top plate, and the two friction power generation modules can convert the translational motion energy of the top plate into electrical energy based on the friction electric effect, which has a higher electromechanical conversion efficiency than the method of collecting vibration energy in the prior art. On this basis, the two switch modules trigger their respective switch signals in succession as the translational motion of the top plate changes, thereby being able to obtain the vehicle's driving speed based on the triggering time difference of the two switch signals and the travel difference of the top plate when the two are triggered, and the vehicle's driving acceleration can also be obtained based on the speed difference and time difference when the front and rear wheels of the vehicle pass through the top plate in turn, thereby forming an integrated solution integrating energy collection and speed sensing functions, and since the top plate is always flush with the road surface being measured, it is possible to avoid bumps and vibration shocks when the vehicle passes by, thereby ensuring the stability and smoothness of the vehicle's passage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the three-dimensional structure of a self-powered vehicle sensor device provided in an embodiment of the present invention; Figure 2 A schematic diagram of the explosion structure of a self-powered vehicle sensor device provided by an embodiment of the present invention; Figure 3 Schematic diagram of the transmission structure of the input gear and the intermediate gear set in the embodiment of the present invention; Figure 4 Schematic diagram of the transmission structure of the output gear and the intermediate gear set in the embodiment of the present invention; Figure 5 A schematic diagram of the three-dimensional structure of a triboelectric unit used in an embodiment of the present invention; Figure 6 Schematic diagram of the circuit structure of the triboelectric unit used in an embodiment of the present invention.

[0017] In the figure: 10, base; 11, support housing; 12, guide rail; 13, sliding seat; 20, top plate; 30, triboelectric unit; 31, tribogeneration module; 311, triboelectric electrode; 32, switch module; 321, movable electrode; 322, fixed electrode; 40, energy conversion and collection mechanism; 41, energy collection assembly; 411, disk; 412, coil; 42, energy conversion assembly; 421, rack; 422, input gear; 423, intermediate gear set; 4231, first gear; 4232, second gear; 4233, third gear; 4234, fourth gear; 4235, reversing gear; 4236, first one-way bearing; 4237, second one-way bearing; 4238, first central shaft; 4239, second central shaft; 424, output gear. Detailed implementation manner

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] It should be noted that when an element is referred to as being "disposed on" or "connected to" another element, it can be directly on the other element or indirectly on the other element. It should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. The terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of the present application, "a plurality of", "several" means two or more, unless otherwise specifically defined.

[0020] Please refer to Figures 1 to 6, the self-powered vehicle sensing device provided by the present invention will be described below. The self-powered vehicle sensing device includes a base 10, a top plate 20 and two triboelectric units 30; the base 10 is used for being embedded and fixed on the road surface to be measured, and the top plate 20 is slidably connected to the base 10 along the vehicle passing direction and is flush with the road surface to be measured; the two triboelectric units 30 are symmetrically connected to both ends of the base 10 and are both connected to the top plate 20; the two triboelectric units 30 each include a triboelectric power generation module 31 and a switch module 32 electrically connected to the triboelectric power generation module 31; the top plate 20 is used for translational movement driven by the wheel friction, the two triboelectric power generation modules 31 are used for triboelectric power generation driven by the translational movement of the top plate 20, and the two switch modules 32 are successively closed driven by the translational movement of the top plate 20 to respectively trigger switch signals; wherein, the time difference and stroke difference triggered by the two switch signals are used to feedback the speed and acceleration of the vehicle.

[0021] It should be understood that in this embodiment, the triboelectric power generation module 31 can specifically be a triboelectric nanogenerator, which is a device that converts mechanical energy into electrical energy by using the principles of triboelectrification and electrostatic induction. When the wheel reaches above the top plate 20 during the vehicle's forward movement, the wheel frictions the top plate 20 and drives the top plate 20 to slide backward relative to the fixed base 10. At this time, the triboelectric power generation module 31 located on the front side of the top plate 20 generates triboelectric power due to stretching, and the triboelectric power generation module 31 located on the rear side of the top plate 20 generates triboelectric power due to compression. Although both of them use the translational movement energy of the top plate 20 for triboelectric power generation, no current can be generated when the two do not form a closed circuit, so there is no signal output. Here, the corresponding switch modules 32 of the two can be set to different trigger strokes. For example, when the top plate 20 moves backward by a first set value, the switch module 32 on its rear side closes, so that the triboelectric power generation module 31 on the rear side of the top plate 20 forms a closed loop and outputs current, that is, triggers a switch signal. When the top plate 20 continues to translate backward until the movement amount reaches a second set value higher than the first set value, the switch module 32 on the front side of the top plate 20 closes. At this time, the triboelectric power generation module 31 on the front side of the top plate 20 obtains a closed loop and outputs current, thereby triggering the next switch signal. Therefore, there is a time difference in the trigger timing of the two switch signals. This time difference reflects the movement time used for the translational amount of the top plate 20 to increase from the first set value to the second set value, that is, the time difference between the triggers of the two switch signals. And the difference between the first set value and the second set value is the stroke difference between the triggers of the two switch signals. This stroke difference reflects the translational distance of the top plate 20 during the time period from triggering the first switch signal to triggering the next switch signal driven by the wheel. The ratio of the above stroke difference to the time difference is the translational movement speed of the top plate 20, and the translational movement speed of the top plate 20 is the rotational linear speed of the wheel, that is, the driving speed of the vehicle.

[0022] On the basis of the above, the front wheel speed can be obtained when the front wheel of the vehicle passes through the top plate 20, and the rear wheel speed can be obtained when the rear wheel of the vehicle passes through the top plate 20, thereby obtaining the speed difference between the front and rear wheels passing through the top plate 20. At the same time, the time difference between the front and rear wheels passing through the top plate 20 can be obtained by the time when the switch signal is triggered when the front and rear wheels pass through the top plate 20. The acceleration of the vehicle can be obtained by taking the ratio of the speed difference between the front and rear wheels to the time difference.

[0023] It should be emphasized that the parameters required for obtaining the vehicle speed and acceleration in this embodiment include the triggering strokes L1 and L2 of the switch modules 32 of the two friction electric units 30, L1 is smaller than L2, and the triggering time points T1 and T2 of the two switch modules 32 when the front wheels of the vehicle pass through the top plate 20. Based on the above parameters, the vehicle front wheel speed V1=(L2-L1) / (T2-T1) can be calculated; and for obtaining the vehicle acceleration, the time points T3 and T4 when the two switch modules 32 are triggered respectively when the rear wheels of the vehicle pass through the top plate 20 are also required, thereby obtaining the vehicle rear wheel speed V2=(L2-L1) / (T4-T3); the acceleration a=(V2-V1) / (T3-T1) of the vehicle when it passes through the top plate 20 can be obtained through the front wheel speed and the rear wheel speed.

[0024] Compared with the prior art, the self-powered vehicle sensing device provided in the present embodiment is capable of providing energy to the two friction electric units 30 through the top plate 20 due to the friction electric effect when the vehicle passes through the top plate 20. The two friction power generation modules 31 can convert the translational motion energy of the top plate 20 into electrical energy based on the friction electric effect, which has a higher energy conversion rate than the vibration energy collection method in the prior art. On this basis, the two switch modules 32 trigger their respective switch signals in succession as the translational motion of the top plate 20 changes, thereby obtaining the vehicle's driving speed based on the triggering time difference of the two switch signals and the travel difference of the top plate 20 when the two are triggered, and obtaining the vehicle's driving acceleration based on the speed difference and time difference when the front and rear wheels of the vehicle pass through the top plate 20 in turn, thereby forming an integrated solution integrating energy collection and speed sensing functions. Since the top plate 20 is always flush with the road surface being measured, it is possible to avoid bumps and vibrations when the vehicle passes by, thereby ensuring the stability and smoothness of the vehicle's passage.

[0025] In some embodiments, see Figure 5 and Figure 6, the switch module 32 includes a movable electrode 321 and two fixed electrodes 322; the movable electrode 321 is connected to the triboelectric power generation module 31 and moves translationally together with the top plate 20, and the two fixed electrodes 322 are respectively fixed on both sides of the movable electrode 321 and are both connected and conducted with the triboelectric power generation module 31; wherein, the initial distances between the movable electrode 321 and the two fixed electrodes 322 are different, and a switch signal is triggered when the movable electrode 321 comes into contact and conducts with any one of the fixed electrodes 322.

[0026] The translational movement of the top plate 20 is used to drive the two triboelectric power generation modules 31 to generate triboelectric power. When the movable electrode 321 following the movement of the top plate 20 contacts one of the fixed electrodes 322, a closed circuit can be formed on the corresponding triboelectric power generation module 31, thereby obtaining a switch signal; specifically, the movable electrode 321 is located between the two fixed electrodes 322 and has different initial distances from the two fixed electrodes 322, that is, the movable electrode 321 is offset between the two fixed electrodes 322 relative to the two fixed electrodes 322. In this way, the two switch modules 32 symmetrically arranged at both ends of the base 10 can obtain different trigger strokes.

[0027] As Figure 6 shown, the movable electrode 321 is defined as K0, and the two fixed electrodes 322 are respectively K1 and K2; the distance between the movable electrode K0 and the fixed electrode K1 is L1, and the distance between the movable electrode K0 and the fixed electrode K2 is L2 (L2 is greater than L1). When the top plate 20 moves backward under the drive of wheel friction (which can be regarded as the situation when a forward-moving vehicle passes by and the situation when a vehicle accelerates forward), the triboelectric power generation module 31 located behind the top plate 20 is compressed to generate triboelectric power, and the triboelectric power generation module 31 located in front of the top plate 20 is stretched to generate triboelectric power. During this process, when the backward translational movement amount of the top plate 20 reaches L1, the movable electrode K0 located in front of the top plate 20 contacts and conducts with the fixed electrode K1, triggering the switch signal of the front triboelectric power generation module 31. When the top plate 20 continues to move until the translational movement amount reaches L2, the movable electrode K0 located behind the top plate 20 contacts and conducts with the fixed electrode K2, triggering the switch signal of the rear triboelectric power generation module 31; similarly, when the top plate 20 moves forward under the drive of wheel friction (which can be regarded as the situation when a reverse-moving vehicle passes by or the situation when a vehicle decelerates forward), the movable electrode K0 located behind the top plate 20 contacts and conducts with the fixed electrode K1 first, triggering the switch signal of the front triboelectric power generation module 31, and the movable electrode K0 located in front of the top plate 20 contacts and conducts with the fixed electrode K2 later, triggering the switch signal of the front triboelectric power generation module 31; therefore, the speed and acceleration of a two-way moving vehicle can be fed back.

[0028] Specifically, please refer to Figure 5, to avoid motion interference, the movable electrode K0 and the fixed electrode K1 are arranged in a vertically offset manner. When one of the movable electrodes K0 reaches a translation amount of L1 under the drive of the top plate 20 and is in vertical alignment and contact conduction with the corresponding fixed electrode K1, when the top plate 20 drives the two movable electrodes 321 to continue translating, this movable electrode 321 slides past the lower side of the fixed electrode K1 until the translation amount reaches L2, and then the other movable electrode 321 makes vertical or horizontal contact conduction with its corresponding fixed electrode K2.

[0029] As a specific implementation of the above triboelectric power generation module 31, please refer to Figure 5 and Figure 6 , the triboelectric power generation module 31 includes a number of friction electrodes 311 connected in sequence to form an elastic folding structure. One end of the elastic folding structure is fixedly connected to the base 10, and the other end is connected to the top plate 20; one end of each friction electrode 311 is connected and conducted with the movable electrode 321, and the other end is connected and conducted with the two fixed electrodes 322. Each friction electrode 311 is used for triboelectric power generation under the drive of the translational movement of the top plate 20.

[0030] When the top plate 20 makes a translational movement, each friction electrode 311 compresses or elongates in an elastic telescopic movement manner, thereby generating a potential difference at both ends of each friction electrode 311 (the friction electrode 311 can specifically be two dielectric films of different materials stacked face to face, with metal electrodes plated on their respective back surfaces. When these two dielectric films come into contact, opposite surface charges will be formed on the two contact surfaces. When these two surfaces are separated due to an external force, a small air gap will be formed in the middle, and an induced potential difference will be formed between the two electrodes. If the two electrodes are connected together through a load, electrons will flow from one electrode to the other through the load, forming a reverse potential difference to balance the electrostatic field. When the air gap between the two friction layers closes, the potential difference formed by the triboelectric charges disappears, and the electrons will flow back). When the movable electrode 321 makes contact conduction with any one of the fixed electrodes 322, a closed circuit can be established on each friction electrode 311 to generate a current signal, and this current signal can be used as a switching signal; when the wheel rolls over the top plate 20, the elastic force of the elastic folding structure can assist the top plate 20 to quickly reset, so as to ensure that the top plate 20 can obtain a stable initial state before the next wheel passes, thereby improving the accuracy of speed detection.

[0031] Exemplarily, such as Figure 5 and Figure 6As shown, the triboelectric power generation module 31 includes eighteen tribo - electrodes 311, which can be specifically named and arranged in sequence as A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R. Each tribo - electrode 311 includes a tribo - inner layer and a tribo - outer layer. Among them, the respective tribo - inner layers are sequentially connected and conductively connected to the movable electrode K0, and the respective tribo - outer layers are sequentially connected and conductively connected to the fixed electrode K1 and the fixed electrode K2 together. Since the respective tribo - electrodes 311 are sequentially folded to form an elastic folding structure with an elastic force similar to that of a spring, compared with the existing energy harvesting method that relies on raised speed bumps, it can not only provide a flatter condition for vehicle passage, but also is not restricted by the vertical space. The tribo - electrodes 311 can be horizontally stacked to increase the number of tribo - electrodes 311, thereby improving the energy harvesting and electromechanical conversion efficiency. At the same time, the horizontal layout can facilitate the horizontal displacement to detect the vehicle speed and acceleration. On this basis, it is also convenient to use the structural elasticity of the respective tribo - electrodes 311 to provide a resilience for the rapid reset of the top plate 20.

[0032] In some possible implementation manners, please refer to Figure 2 , the self - powered vehicle sensing device further includes an energy conversion and collection mechanism 40 and a control circuit board. The control circuit board is electrically connected to the two triboelectric units 30 respectively and is used to receive switch signals. A power storage element is provided on the control circuit board. The energy conversion and collection mechanism 40 includes an energy collection component 41 and an energy conversion component 42. The energy collection component 41 is connected to the center of the base 10, and the energy conversion component 42 is connected to the top plate 20 and is drivingly connected to the energy collection component 41. Among them, the energy conversion component 42 is used to convert the translational motion energy of the top plate 20 into rotational mechanical energy and transmit it to the energy collection component 41. The energy collection component 41 is electrically connected to the control circuit board and is used to convert the rotational mechanical energy into electrical energy and store it in the power storage element.

[0033] It should be noted that the control circuit board actually serves as a sensing and control element for data acquisition, processing, and wireless transmission, and can also be understood as a sensing controller. Its structure and working principle are prior arts and will not be elaborated here. In this embodiment, the control circuit board can be integrally arranged between the top plate 20 and the base 10, or can be externally connected. Here, the integrated installation method can be preferably adopted.

[0034] Considering that the energy driven by wheel friction to move the top plate 20 is very large, even if two friction electric units 30 are used for energy collection, there is still a lot of energy loss, and considering that the external transmission of signals needs to rely on the wireless transmission chip on the control circuit board, when the switch signal of the friction electric unit 30 is triggered, it is fed back to the wireless transmission chip, and the switch signal is wirelessly transmitted to the remote end through the wireless transmission chip for data processing (considering that the additional data processing module of the wireless transmission chip will increase energy consumption, only data collection and remote wireless transmission can be performed here, and then the final data processing and analysis are performed by the remote processor, that is, the remote processor is used to calculate the vehicle speed and acceleration according to the trigger time of the switch signal), so the control circuit board itself also requires power consumption. Consumption, relying solely on the conversion of mechanical energy by the friction electric unit 30 may lead to insufficient power supply to the control circuit board. Therefore, an energy conversion and collection mechanism 40 is set between the top plate 20 and the base 10, and the energy conversion component 42 is used to convert the translational motion energy of the top plate 20 into rotational mechanical energy and transmit it to the energy collection component 41, and then the energy collection component 41 is used to convert the rotational mechanical energy into electrical energy, so as to charge the energy storage element such as a supercapacitor or a battery, and then the energy storage element is used to power the control circuit board. It can not only meet the power demand of the device itself and improve the electromechanical conversion efficiency, but also can use the energy conversion and collection mechanism 40 to reduce the impact force of the top plate 20 on the base 10, which is beneficial to improve the service life of the overall structure of the device.

[0035] Specifically, the optional structure of the energy conversion component 42 in this embodiment is as follows: Figure 2 As shown, the energy conversion component 42 includes a rack 421, an input gear 422, an intermediate gear set 423 and an output gear 424; the rack 421 is fixedly connected to the top plate 20 along the direction of vehicle travel, the input gear 422 is rotatably connected to the base 10 and meshes with the rack 421, and the output gear 424 is connected to the energy collection component 41 and is transmission-connected to the input gear 422 through the intermediate gear set 423; wherein the intermediate gear set 423 is used to convert the bidirectional rotational motion of the input gear 422 into the unidirectional rotational motion of the output gear 424.

[0036] The top plate 20 generates a translational motion driven by the wheel friction force, so that the rack 421 drives the input gear 422 to rotate. Then, the intermediate gear set 423 transmits the torque of the input gear 422 to the output gear 424, thereby obtaining rotational mechanical energy on the output gear 424 and transmitting it to the energy collection assembly 41. The function of the intermediate gear set 423 is that regardless of the rotation direction of the input gear 422 driven by the rack 421, the rotation direction finally transmitted to the output gear 424 is always unified. That is to say, whether it is a vehicle traveling forward or backward, and whether the vehicle is accelerating or decelerating, as long as the wheel passes over the top plate 20, it can finally make the output gear 424 form a fixed rotation direction, thereby improving the electromechanical conversion efficiency and the adaptability of speed sensing detection.

[0037] In some embodiments, referring to Figures 2 to 4 , the intermediate gear set 423 includes a first gear 4231, a second gear 4232, a third gear 4233, a fourth gear 4234 and a reversing gear 4235 rotatably connected to the base 10; the first gear 4231 meshes with the input gear 422 and is connected to the third gear 4233 through a first one-way bearing 4236, the reversing gear 4235 meshes with the input gear 422, the second gear 4232 meshes with the reversing gear 4235 and is connected to the fourth gear 4234 through a second one-way bearing 4237, and both the third gear 4233 and the fourth gear 4234 mesh with the output gear 424.

[0038] When the rack 421 drives the input gear 422 to rotate forward, the first gear 4231 meshing with it obtains a reverse torque and transmits the reverse torque to the third gear 4233 through the first one-way bearing 4236, and then transmits the torque to the output gear 424 through the third gear 4233, so that the output gear 424 obtains the same forward torque as the input gear 422. During this process, the second gear 4232 rotates forward due to the transmission of the reversing gear 4235, so it cannot drive the fourth gear 4234 to rotate through the second one-way bearing 4237, that is, both the second gear 4232 and the fourth gear 4234 rotate idly and do not transmit power; when the rack 421 drives the input gear 422 to rotate reversely, the reversing gear 4235 meshing with it obtains a forward torque, and the second gear 4232 meshing with the reversing gear 4235 obtains a reverse torque, so as to drive the fourth gear 4234 to obtain a reverse torque through the second one-way bearing 4237, and then drive the output gear 424 to rotate forward through the fourth gear 4234. During this process, the first gear 4231 rotates forward under the drive of the input gear 422, so it cannot transmit torque to the third gear 4233 through the first one-way bearing 4236, so both the first gear 4231 and the third gear 4233 rotate idly and do not transmit power. Therefore, no matter whether the input gear 422 rotates forward or reversely, the final output gear 424 will rotate forward, that is, the bidirectional movement of the top plate 20 driven by the wheel friction will ultimately be converted into a unidirectional rotational movement in the same direction of the output gear 424, thereby improving the flexibility and efficiency of road energy collection.

[0039] It should be noted that, as Figure 2 shown, a support housing 11 is fixedly connected to the base 10. The input gear 422, the first gear 4231, the second gear 4232 and the reversing gear 4235 are all rotatably connected to the outer top wall of the support housing 11, and the output gear 424, the third gear 4233, the fourth gear 4234 and the energy collection assembly 41 are all arranged inside the support housing 11. The main function of the support housing 11 is to meet the vertical misalignment installation of the input gear 422 and the output gear 424, and at the same time provide a protective space for the energy collection assembly 41, improving the compactness of the overall structural layout and the transmission stability.

[0040] Furthermore, please refer to Figure 2 , a first one-way bearing 4236 is embedded in the center of the third gear 4233, and a second one-way bearing 4237 is embedded in the center of the fourth gear 4234; the first gear 4231 is provided with a first central shaft 4238, and the first central shaft 4238 rotatably passes through the support housing 11 and is connected to the first one-way bearing 4236; the second gear 4232 is provided with a second central shaft 4239, and the second central shaft 4239 rotatably passes through the support housing 11 and is connected to the second one-way bearing 4237.

[0041] The one-way bearing has the characteristic of one-way rotation. It can rotate freely in one direction, while being restricted in the other direction, thus playing the role of one-way transmission. Here, the first central shaft 4238 and the second central shaft 4239 can be connected to the support housing 11 through a conventional two-way bearing embedded in the top wall of the support housing 11, so as to ensure the connection stability between the first gear 4231 and the second gear 4232; on the basis of the connection between the third gear 4233 and the first central shaft 4238 by using the first one-way bearing 4236, the third gear 4233 can be further connected to the base 10 through a conventional two-way bearing embedded in the base 10; similarly, the fourth gear 4234 can also be connected to the base 10 through a conventional two-way bearing embedded in the base 10 on the basis of the connection between the fourth gear 4234 and the second central shaft 4239 by using the second one-way bearing 4237, thereby improving the connection reliability and transmission stability of the third gear 4233 and the fourth gear 4234.

[0042] Exemplarily, as Figure 2 shown, the above-mentioned energy harvesting assembly 41 includes a disk 411 and a plurality of coils 412; each coil 412 is circumferentially and arrayedly distributed at the center of the base 10, the disk 411 is rotatably connected to the base 10 and corresponds to each coil 412 up and down, and the disk 411 is fixedly connected to the output gear 424.

[0043] Here, a plurality of permanent magnets are circumferentially and arrayedly distributed on the disk 411 corresponding to each coil 412. When the disk 411 rotates driven by the energy conversion assembly 42, a relative movement is formed between the permanent magnets distributed on the disk 411 and the coils 412. At this time, the coils 412 generate electricity based on the law of electromagnetic induction, thereby converting the rotational mechanical energy transmitted from the energy conversion assembly 42 to the disk 411 through the output gear 424 into electrical energy. The number of permanent magnets distributed in the circumferential array on the disk 411 determines the working frequency of the electromechanical conversion, and the magnetic poles of adjacent permanent magnets should be staggered to increase the magnetic flux change rate, thereby improving the electromechanical conversion efficiency.

[0044] In some embodiments, please refer to Figure 2 , two guide rails 12 are arranged on the base 10 in parallel and at intervals. The guide rails 12 extend along the vehicle passing direction, and each guide rail 12 is slidably connected with a sliding seat 13. The top plate 20 is fixedly connected to each sliding seat 13. Here, by providing two guide rails 12 and cooperating with the sliding seats 13 to support the top plate 20, the sliding smoothness of the top plate 20 under the load state can be improved, which is not only beneficial to improving the electromechanical conversion efficiency, but also can improve the translational motion response speed of the top plate 20 driven by the wheel friction, thereby improving the accuracy of speed sensing detection.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. Self-powered vehicle sensing device, characterized in that, It includes a base, a top plate and two friction electric units; the base is used to be embedded and fixed on the road surface to be tested, and the top plate is slidably connected to the base along the direction of vehicle travel and is flush with the road surface to be tested; the two friction electric units are symmetrically connected to the two ends of the base and are both connected to the top plate; the two friction electric units each include a friction power generation module and a switch module electrically connected to the friction power generation module; the top plate is used for translational movement driven by wheel friction, the two friction power generation modules are used for friction power generation driven by the translational movement of the top plate, and the two switch modules are closed successively driven by the translational movement of the top plate to trigger switch signals respectively; wherein the time difference and travel difference triggered by the two switch signals are used to feedback the speed and acceleration of the vehicle.

2. The self-powered vehicle sensing device according to claim 1, characterized in that, The switch module includes a movable electrode and two fixed electrodes; the movable electrode is connected to the friction power generation module and moves translationally with the top plate, and the two fixed electrodes are respectively fixed on both sides of the movable electrode and are both connected and conductive with the friction power generation module; wherein the initial spacing between the movable electrode and the two fixed electrodes is different, and a switch signal is triggered when the movable electrode contacts and is conductive with any of the fixed electrodes.

3. The self-powered vehicle sensing device according to claim 2, wherein The friction power generation module includes a plurality of friction electrodes connected in sequence to form an elastic folding structure, one end of the elastic folding structure is fixedly connected to the base, and the other end is connected to the top plate; one end of each of the friction electrodes is connected and conducted to the movable electrode, and the other end is connected and conducted to the two fixed electrodes, and each of the friction electrodes is used to generate friction power driven by the translational movement of the top plate.

4. The self-powered vehicle sensing device according to claim 1, wherein, The self-powered vehicle sensor device also includes an energy conversion and collection mechanism and a control circuit board; the control circuit board is electrically connected to the two friction electric units respectively and is used to receive the switch signal, and a storage element is provided on the control circuit board; the energy conversion and collection mechanism includes an energy collection component and an energy conversion component; the energy collection component is connected to the center of the base, and the energy conversion component is connected to the top plate and is transmission-connected to the energy collection component; wherein the energy conversion component is used to convert the translational motion energy of the top plate into rotational mechanical energy and transmit it to the energy collection component, and the energy collection component is electrically connected to the control circuit board and is used to convert the rotational mechanical energy into electrical energy and store it in the storage element.

5. The self-powered vehicle sensing device according to claim 4, wherein The energy conversion component includes a rack, an input gear, an intermediate gear set and an output gear; the rack is fixedly connected to the top plate along the direction of vehicle travel, the input gear is rotatably connected to the base and meshes with the rack, and the output gear is connected to the energy collection component and is transmission-connected to the input gear through the intermediate gear set; wherein the intermediate gear set is used to convert the bidirectional rotational motion of the input gear into the unidirectional rotational motion of the output gear.

6. The self-powered vehicle sensing device according to claim 5, wherein, The intermediate gear set includes a first gear, a second gear, a third gear, a fourth gear and a reversing gear rotatably connected to the base; the first gear meshes with the input gear and is connected to the third gear through a first one-way bearing, the reversing gear meshes with the input gear, the second gear meshes with the reversing gear and is connected to the fourth gear through a second one-way bearing, and both the third gear and the fourth gear mesh with the output gear.

7. The self-powered vehicle sensing device according to claim 6, wherein A support housing is fixedly connected to the base, and the input gear, the first gear, the second gear and the reversing gear are all rotatably connected to the outer top wall of the support housing, and the output gear, the third gear, the fourth gear and the energy collection assembly are all arranged inside the support housing.

8. The self-powered vehicle sensing device according to claim 7, wherein The first one-way bearing is embedded in the center of the third gear, and the second one-way bearing is embedded in the center of the fourth gear; the first gear is provided with a first central shaft, and the first central shaft rotatably passes through the support housing and is connected to the first one-way bearing; the second gear is provided with a second central shaft, and the second central shaft rotatably passes through the support housing and is connected to the second one-way bearing.

9. The self-powered vehicle sensing device according to claim 5, wherein, The energy collection assembly includes a disk and a plurality of coils; each of the coils is circumferentially and arrayedly distributed at the center of the base, the disk is rotatably connected to the base and is vertically corresponding to each of the coils, and the disk is fixedly connected to the output gear.

10. The self-powered vehicle sensing device according to any one of claims 1-9, characterized in that, Two guide rails are arranged on the base in parallel at intervals, the guide rails extend along the vehicle passing direction, and a sliding seat is slidably connected to each of the guide rails, and the top plate is fixedly connected to each of the sliding seats.

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