CN107612418A - Automobile tire Non-Linear Vibration TRT based on centrifugal forces affect - Google Patents

Abstract

The invention discloses a non-linear vibration power generation device for automobile tires based on the influence of centrifugal force, which includes a base of the power generation device, a vibration power generation unit and a detection unit, the base of the power generation device is connected with the vibration power generation unit and the detection unit, and then the base of the power generation device is connected to the vibration power generation unit through a U-shaped groove. The wheel hub is fixed, the vibration unit is fixed along the centrifugal direction of the wheel hub through the fixed end of the cantilever beam, and the centrifugal distance between the first magnetic mass block and the tire rotation center wheelbase can be adjusted; the detection unit is fixed to one end of the base of the power generation device by bolts. The invention can increase the response frequency band of the system by utilizing the influence of the centrifugal force with dynamic characteristics, realize the high output response of the wide frequency band, improve the performance of the actual automobile vibration power generation, and solve the problem of difficult power supply of high-speed rotating tires.

Description

Nonlinear vibration power generation device for automobile tires based on centrifugal force

technical field

The invention belongs to the technical field of vibration power generation, in particular to a non-linear vibration power generation device for automobile tires based on the influence of centrifugal force.

Background technique

With the introduction of the concept of Internet of Vehicles (IoV), sensing and testing equipment tends to be low-power, integrated, and miniaturized, and more and more sensors are urgently needed to monitor various information on the vehicle body. However, How to sustainably provide stable power supply to sensors and establish a green and low-carbon Internet of Vehicles system has become an urgent problem to be solved; therefore, collecting the vibration energy existing in the automotive environment to realize the self-power supply technology of sensing equipment has attracted widespread attention from all over the world. and support. At present, vibration power generation technology is mainly divided into three categories: electromagnetic power generation, electrostatic power generation and piezoelectric power generation. Electromagnetic power generation uses the phenomenon of electromagnetic induction. Electrostatic power generation uses the relative motion between permanent pole materials to change the effective displacement and area to generate charge outflow; piezoelectric power generation uses the unique physical properties of piezoelectric materials to convert the stress generated by external vibrations Converted into electrical energy, a cantilever beam with a magnetic mass at the end and piezoelectric materials pasted on its surface is the most representative structure of piezoelectric power generation technology. The above three power generation methods mostly use the linear resonance phenomenon to improve the power generation efficiency by adjusting the natural frequency of the power generation device to be consistent with the vibration frequency of the environment. High power generation performance is still maintained under high-band input conditions, so relying on the current traditional linear power generation technology for energy recovery, the power generation capacity is at a low level.

In order to solve the narrow-band response problem of traditional linear power generation devices, in 2010 Gu, L. et al. (Gu, L., Livermore, C., Passive self-tuning energy harvester for extracting energy from rotational motion. Applied Physics Letters, 97(8):081904, 2010.) proposed to use the influence of rotation to generate centrifugal force, change the natural frequency of the system itself by adjusting the equivalent elastic coefficient of the cantilever beam, and optimize the system parameters in advance to achieve the matching of the natural frequency and the rotation frequency, thus The purpose of increasing the power generation is achieved; however, due to the fact that it is difficult to ensure that the frequency is completely consistent during the frequency matching process of this method, the effective power generation frequency band is narrow, which leads to low practicability. Therefore, Roundy, S. et al. (Roundy, S., Tola, J., Energyharvester for rotating environments using offset pendulum and nonlinear dynamics. Smart Materials and Structures, 23(10): 105004, 2014.) of the University of Utah in the United States proposed a single pendulum The nonlinear power generation system can solve the problem that the vibration of the linear system is limited by the maximum stroke by using the characteristic phenomenon of the nonlinear system, and can realize vibration with wide frequency and large amplitude, thereby improving the power generation performance of the system; but this technology still has certain limitations The positive effect of centrifugal force on stabilizing high-energy orbital vibration is not utilized, resulting in the rotation frequency of effective power generation being kept within a fixed frequency range. When the rotational speed is too high, the response of the system is the cause of low-energy orbital vibration. The effect is still not particularly ideal.

Contents of the invention

In order to improve the power generation performance of the power generation device and solve the narrow frequency band response problem of the traditional power generation system, the present invention proposes a non-linear cantilever beam structure power generation device that can be applied to automobile tire power generation and further broadens the system response frequency band by utilizing the influence of rotating centrifugal force. For the rotation frequency of different tires, through the optimization design of parameters and Duffing kinematics analysis, it is found that the power generation can not be limited by the vehicle speed and can be stabilized on a high-output energy track, thereby increasing the response frequency range and improving power generation. performance. Therefore, the goal of self-powering the tire pressure monitoring system can be achieved, thereby solving the problem of difficult power supply for high-speed rotating tires.

In order to achieve the above object, the present invention adopts the following technical solutions:

The non-linear vibration power generation device for automobile tires based on the influence of centrifugal force includes a power generation device base, a vibration power generation unit and a detection unit. fixed;

The vibration generating unit includes a cantilever beam, a first magnetic mass block, a second magnetic mass block, and a piezoelectric material pasted on the surface of the cantilever beam. One end of the cantilever beam is fixed at the fixed end of the cantilever beam, and the fixed end of the cantilever beam passes through Bolts are fixed on the base of the power generation device, the other end of the cantilever beam is a free end, and the first magnetic mass block is fixed along the central axis of tire rotation and the centrifugal direction of the fixed end of the cantilever beam, and the first magnetic mass block is diagonally opposite to a certain distance Fixing the second magnetic mass block, the second magnetic mass block is fixed on the balance mass block along the horizontal direction and through the position adjustment thread of the second magnetic mass block, and the balance mass block is fixed to one end of the base of the power generation device by bolts;

The detection unit is fixed on the other end of the base of the power generation device by bolts, the detection unit includes a voltage detector, an acceleration detector and a Bluetooth data transmission device, the voltage detector is used to detect the output voltage of the piezoelectric material, and the voltage The data collected by the detector is stored in the voltage detector itself, and the acceleration detector is used to detect the acceleration of the tire, and the data collected by the acceleration detector is transmitted to the computer through the Bluetooth data transmission device;

The shape of the power generation device base is rectangular, and the long side of the rectangle is provided with grooves, so that the power generation device base forms two parts with different widths, and two rows of parallel cantilever beams are fixed on the two narrower long sides. The end position adjustment bolt is used to adjust the position of the fixed end of the cantilever beam. Two rows of parallel fixed end bolt holes of the second magnetic mass block are provided on the two wide long sides for adjusting the position of the fixed end of the second magnetic mass block.

In the above solution, there is an adjustable centrifugal distance l' from the center of gravity of the first magnetic mass to the central axis of tire rotation.

Preferably, the piezoelectric material is a ceramic material.

Preferably, the materials of the first magnetic mass block and the second magnetic mass block are powerful permanent magnets.

Preferably, the material of the cantilever beam is stainless steel.

The beneficial effects of the present invention are: the present invention utilizes the advantages of the high-energy track of the nonlinear bistable system, and combines the dynamic characteristics of the centrifugal force generated by the rotation of the tire, so that the equivalent elastic coefficient of the cantilever beam increases with the increase of the rotation frequency of the tire. The depth of the two potential wells leading to the bistable state gradually becomes shallower, and finally the cantilever beam evolves from the original nonlinear bistable system to a nonlinear monostable system, and the original bistable high-energy orbital vibration phenomenon gradually becomes nonlinear Drift on a monostable high-energy track; use the combination of two nonlinear high-energy track vibration phenomena to further expand the advantages of this power generation device, so as to achieve the goal of high-efficiency power generation in a wide range of vehicle speeds.

Description of drawings

In order to illustrate the embodiment of the present invention and its effectiveness more clearly, the embodiment and the results of experimental verification will be introduced in the form of drawings below.

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of the vibration generating unit of the present invention;

Figure 3 is a characteristic diagram of the vehicle speed and the output response of the cantilever beam speed.

Among them, reference numerals: 01-generating device base; 02-screw hole at the fixed end of the second magnetic mass block; 03-second magnetic mass block; 04-cantilever beam; 05-piezoelectric material; 06-fixed end of the cantilever beam ;07-position adjustment thread of the second magnetic mass block; 08-fixed end of the second magnetic mass block; 09-first magnetic mass block; 10-rotation center axis of the tire; Detection device; 13-tire.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. It is not intended to indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and thus should not be construed as limiting the invention.

As shown in Figure 1, the automobile tire nonlinear vibration power generation device based on the influence of centrifugal force comprises a power generation device base (01), a vibration power generation unit and a detection unit 12, and the power generation device base 01 is connected to the vibration power generation unit and the detection unit 12, and then The power generation device base 01 is fixed to the hub through a U-shaped groove; the shape of the power generation device base 01 is a rectangle, and the long side of the rectangle has grooves, so that the power generation device base 01 forms two parts with different widths, and the narrower one There are two rows of parallel cantilever beam fixed end position adjustment bolts 11 on the two long sides, which are used to adjust the position of the cantilever beam fixed end 06, and two rows of parallel second magnetic mass block fixed ends are provided on the two wide long sides The bolt hole 02 is used to adjust the position of the fixed end 08 of the second magnetic mass block.

The vibration generating unit includes a cantilever beam 04 (stainless steel material), a first magnetic mass block 09, a second magnetic mass block 03, and a piezoelectric material 05 (made of ceramic material) pasted on the surface of the cantilever beam 04 to ensure that the stress generated by the vibration can be high-efficiency conversion into electrical energy), the materials of the first magnetic mass block 09 and the second magnetic mass block 03 are strong permanent magnets, and when the cantilever beam 04 is kept horizontal, the polarity distribution of the permanent magnets is also adjusted along the horizontal direction Installed on the free end of the cantilever beam 04; one end of the cantilever beam 04 is fixed to the fixed end 06 of the cantilever beam, and the fixed end 06 of the cantilever beam is fixed on the base 01 of the power generation device through bolts, and the other end of the cantilever beam 04 is a free end, which rotates along the tire The central axis 10 and the centrifugal direction of the cantilever beam fixed end 06 fix the first magnetic mass block 09, and fix the second magnetic mass block 03 at a certain distance diagonally opposite the first magnetic mass block 09, and the second magnetic mass block 03 and the first magnetic mass block The polarity distribution direction of 09 is opposite, which will generate mutual repulsive magnetic force. Due to the existence of repulsive force, the cantilever beam 04 changes from the initial linear system to a nonlinear system. When the distance between the two magnetic mass blocks is adjusted to be close enough, The cantilever beam 04 begins to deviate from the initial equilibrium position under the action of the repulsive force of the first magnetic mass block 09, and stops at a new nonlinear equilibrium point, thereby generating a bistable point; the second magnetic mass block 03 moves along the horizontal direction and passes The second magnetic mass position adjustment thread 07 is fixed on the balance mass 08, and the balance mass 08 is fixed on the left end of the generator base 01 by bolts.

The detection unit 12 is fixed on the rightmost end of the generator base 01 by bolts. The detection unit 12 includes a voltage detector (DSO Nano v3, SeeedStudio), an acceleration detector and a Bluetooth data transmission device (MVP-RF3-J, MicroStone), a voltage The detector is used to detect the output voltage of the piezoelectric material 05, and the data collected by the voltage detector is stored in the body of the voltage detector itself, and the acceleration detector is used to detect the acceleration of the tire 13, and the data collected by the acceleration detector is transmitted through the Bluetooth data transmission device computer.

Figure 2 shows the vibration power generation unit, the cantilever beam 04 is fixed at the fixed end 06 of the cantilever beam, the center of gravity of the first magnetic mass block 09 is at an eccentric distance from the center axis of tire rotation 10 l', when the hub does not rotate, Under the action of the magnetic repulsion force F _mag of the second magnetic mass block 03 , the first magnetic mass block 09 rests at the upper equilibrium point of the bistable state, and also rests at the lower equilibrium point depending on the initial state.

The working process of the nonlinear vibration power generation device for automobile tires based on the influence of centrifugal force is as follows:

When the tire 13 rotates counterclockwise with the hub around the tire rotation center axis 10, the first magnetic mass 09 generates a periodic input excitation with the same rotation frequency as the tire 13 under the action of its own gravity, and with the increase of the excitation frequency The response of the cantilever beam 04 gradually jumps from the low-energy orbital motion to the high-energy orbital motion. At the same time, due to the increase of the rotation speed of the tire 13 and the centrifugal distance l' between the center of gravity of the first magnetic mass 09 and the tire rotation central axis 10, the first magnetic The centrifugal force generated by the mass block 09 becomes larger and larger, and the effect on the equivalent elastic coefficient of the cantilever beam 04 becomes non-negligible.

As the rotation speed of the tire 13 increases, the first magnetic mass 09 will generate a rotating centrifugal force _Fc , and the components ft and _fc of the rotating centrifugal force Fc are respectively along the direction perpendicular to the cantilever beam 04 and along the direction of the cantilever beam 04 (Fig. 2). The centrifugal force ft in the direction will increase the restoring force of the cantilever beam 04, which is equivalent to increasing the equivalent elastic coefficient of the cantilever beam 04, thus realizing the transformation of the linear equivalent coefficient of the cantilever beam 04 from the initially negative characteristic (bistability) into a positive characteristic (monostability).

In this embodiment, the promotion effect of centrifugal force on power generation performance is verified by applying a nonlinear power generation device. In order to observe the phenomenon of high-energy track drift within a maximum speed of 40km/h, the inherent elastic coefficient of the cantilever beam 04 is designed to be 30N/m. The mass of a magnetic mass block 09 is 8g, the linear coefficient between magnets is 10N/m, and the nonlinear coefficient between magnets is 2×10 ⁴ N/m ³ ; in order to ensure that the cantilever beam 04 has obvious displacement characteristics during the vibration process, the ideal The power generation effect of the cantilever beam 04 is made of extremely thin 0.2mm stainless steel material, and the length of the cantilever beam 04 is 4.6cm; the specific implementation of the experiment is to compare the power generation of different centrifugal distances, and verify this embodiment by driving at different speeds for each distance effectiveness.

The comparative experimental conditions are as follows: ①The centrifugal distance l' is 0cm (center of rotation) ②The centrifugal distance l' is 3.6cm ③The centrifugal distance l' is 7cm, that is, the centrifugal force is not considered, and based on the simulation results (Figure 3), the centrifugal distance l' is the most The best location and the location with the centrifugal distance l' too far are used as three cases for real vehicle verification; corresponding to three different centrifugal distances, the vehicle speed is increased from 10km/h to 40km/h at intervals of 5km/h, and each speed is maintained Walk the same distance at a constant speed, based on the large internal resistance of the piezoelectric material 05, this verification experiment selects the external resistance as 150kΩ; the position adjustment screw hole 11 of the fixed end of the cantilever beam adjusts the fixed end 06 of the cantilever beam to change l', and at the same time the second The magnetic mass position adjustment thread 07 adjusts the second magnetic mass 03 to ensure a constant distance between the second magnetic mass 03 and the first magnetic mass 09 .

When the centrifugal distance l' is 0cm, as shown in the simulation results in Figure 3, due to the influence of the nonlinear bistable high-energy orbit, the response can maintain a high output in a certain speed range, and the speed output response increases with the increase of the vehicle speed. When the vehicle speed exceeds 27.8km/h, the output response of the cantilever beam velocity will drop from the high-energy track to the low-energy track, and the low-energy track will continue to vibrate up to 40km/h. The experiment uses MATLAB to calculate the effective value (RMS) of the output instantaneous voltage of the piezoelectric material 05. When the vehicle speed is less than 15km/h, the output instantaneous voltage effective value is at a relatively low level (0V～0.8V); the vehicle speed range is 15km/h-25km /h, the effective value of the output instantaneous voltage can reach a relatively high level (2.2V～2.3V); when the vehicle speed exceeds 25km/h, in the range of 30km/h-40km/h, due to the impact of the high-energy track falling to the low-energy track, the output The effective value of the instantaneous voltage drops to a lower level (1.2-1.5V), which is consistent with the variation characteristics of the simulation results. Therefore, when the centrifugal distance l' is 0cm, the effective power generation speed range is 15km/h-25km/h. Based on the vibration table detection of the same period of gravity acceleration output before the experiment, when the cantilever beam is in low-energy orbital vibration (vibration in an independent potential well), the output voltage range is at a low level of 0V-1.58V; when the cantilever beam is in high-energy orbital vibration When (vibration between two potential wells), the output voltage range is 1.85V-2.4V, and this range or higher level is a higher level.

When the centrifugal distance l' is 3.6cm, even if the effective power generation vehicle speed exceeds 25km/h, the speed output of the power generation device shown in Figure 3 will continue to remain stable on the high-response high-energy track, and remain at 40km/h. The experimental calculation shows that: within the speed of 10km/h-40km/h, the effective value of the instantaneous output voltage of the piezoelectric material 05 has been kept at a relatively high level (1.9V-2.5V), which is consistent with the variation characteristics of the simulation results, so the centrifugal distance l 'When it is 3.6cm, the effective power generation speed range is increased to 10km/h-40km/h.

When the centrifugal force distance l' is 7cm, because the centrifugal distance l' is too far, the equivalent linear coefficient increases too fast, and the cantilever beam 04 changes from the nonlinear bistable state to the monostable state prematurely, so that the cantilever beam 04 does not In response to the high-energy orbital motion of the bistable state, the power generation performance of the power generation device becomes lower, and the calculated effective voltage value of the output instantaneous voltage is at a relatively low level (0.55V-1.32V).

Therefore, considering the influence of centrifugal force, when the centrifugal distance is adjusted to the optimal position (l' is 3.6cm), the steady-state characteristics of the cantilever beam 04 can be changed smoothly, and the power generation of the power generation device can always be stabilized at a higher output level. superior.

Through the invention, the average power generation can reach 60 μW, which meets the power consumption requirement of the tire pressure monitoring system of 5 μW. It should be noted that this invention selects the cantilever beam 04 with a low elastic coefficient (30N/m) in order to verify the phenomenon of high-energy track drift at a maximum speed of 40km/h. If the maximum vehicle speed is further increased, by increasing the inherent elastic coefficient of the cantilever beam 04 itself, the vibration response of the cantilever beam 04 can be increased from the nonlinear bistable high-energy track drift to the rotation frequency of the nonlinear monostable high-energy track, thereby improving the The effective vehicle speed range of high-efficiency power generation by the power generation device, that is, the device is generally applicable to the specific situation of the actual vehicle speed.

The above is a brief description of the present invention, and is not limited by the above-mentioned scope of work. As long as the ideas and working methods of the present invention are adopted, simple modifications are applied to other equipment, or improvements and modifications are made without changing the main concept of the present invention. All other actions are within the protection scope of the present invention.

Claims (8)

1. The non-linear vibration power generation device of automobile tires based on the influence of centrifugal force is characterized in that, comprising a power generation device base (01) and a vibration power generation unit, The vibration generating unit includes a cantilever beam (04), a first magnetic mass block (09), a second magnetic mass block (03) and a piezoelectric material (05) pasted on the surface of the cantilever beam (04), the cantilever beam (04) One end is fixed to the fixed end of the cantilever beam (06), the fixed end of the cantilever beam (06) is fixed on the power generation device base (01) by bolts, the other end of the cantilever beam (04) is a free end, along The first magnetic mass (09) is fixed in the centrifugal direction of the tire rotation central axis (10) and the fixed end of the cantilever beam (06), and the second magnetic mass (09) is fixed at a certain distance diagonally opposite the first magnetic mass (09). 03), the second magnetic mass (03) is fixed on the balance mass (08) along the horizontal direction and through the second magnetic mass position adjustment thread (07), and the balance mass (08) is fixed by bolts At one end of the generator base (01). 2. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that, the power generation device also includes a detection unit (12), and the detection unit (12) is fixed on the base of the power generation device by bolts. The other end of the seat (01), the detection unit (12) includes a voltage detector, an acceleration detector and a Bluetooth data transmission device, the voltage detector is used to detect the output voltage of the piezoelectric material (05), and the voltage detector The collected data is stored in the voltage detector itself, and the acceleration detector is used to detect the acceleration of the tire (13), and the data collected by the acceleration detector is transmitted to a computer through a bluetooth data transmission device. 3. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 2, characterized in that, the power generation device base (01) is connected with a vibration power generation unit and a detection unit (12), and then the power generation device base (01) Fix with the hub through U-groove. 4. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that, the shape of the power generation device base (01) is a rectangle, and the long side of the rectangle has a groove, so that The power generation device base (01) forms two parts with different widths, and two rows of parallel cantilever beam fixed end position adjustment bolts (11) are provided on the two narrower long sides for adjusting the position of the cantilever beam fixed end (06). , two rows of parallel bolt holes (02) at the fixed end of the second magnetic mass block are provided on the two long sides with a wider width for adjusting the position of the fixed end (08) of the second magnetic mass block. 5. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that, the piezoelectric material (05) is a ceramic material. 6. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that, the materials of the first magnetic mass (09) and the second magnetic mass (03) are strong permanent magnet. 7. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that, the material of the cantilever beam (04) is stainless steel. 8. The automobile tire nonlinear vibration power generation device based on the influence of centrifugal force as claimed in claim 1, characterized in that there is an adjustable centrifugal force from the center of gravity of the first magnetic mass (09) to the tire rotation central axis (10). distance l'.