Direct drive energy collector with human motion speed self-sensing function

Abstract

The present application relates to the technical field of energy collector, especially to a direct drive type energy collector with human motion speed self-sensing function, comprising a shell, an electromagnetic collection unit, a direct drive excitation input unit and a piezoelectric sensing unit arranged on the shell; the shell comprises a first shell, a support plate and a second shell; the electromagnetic collection unit comprises a containing cavity, a plurality of hollow copper coils and a mover assembly arranged in the containing cavity and capable of reciprocating along the axial direction; the direct drive excitation input unit comprises a non-magnetic through bolt, a connecting rod, a transmission bearing, a crank shaft, a second one-way bearing, a driven gear, a double gear, a transmission shaft, a first one-way bearing and a driving gear, the first one-way bearing penetrates through the second shell, the first one-way bearing is connected with a swing rod, and a mass block is arranged at the bottom end of the swing rod; the piezoelectric sensing unit comprises a cantilever beam fixing seat, a piezoelectric cantilever beam, an end magnet and an excitation magnet. The present application realizes energy collection and speed sensing.

Description

Technical Field

[0001] This invention relates to the field of energy harvester technology, and in particular to a direct-drive energy harvester with a human motion speed self-sensing function. Background Technology

[0002] Existing rotary electromagnetic energy harvesting devices typically include a housing, shaft, rotor, permanent magnet, coil, bearing, and rectifier energy storage circuit. The basic structure is as follows: the permanent magnet is mounted on the rotor, and the coil is fixed to the housing or stator support. When human movement causes the housing to oscillate, vibrate, or change posture, the rotor rotates relative to the housing due to inertia. The permanent magnet on the rotor rotates accordingly, causing a change in the magnetic flux in the coil area, thereby generating an induced electromotive force in the coil. Some structures also incorporate an eccentric mass block, pendulum, gear transmission mechanism, or inertial flywheel on the rotor to enhance the rotational effect at low speeds.

[0003] While this type of rotary electromagnetic energy harvesting device can convert mechanical motion into electrical energy, it suffers from the following shortcomings in practical use: the magnetic circuit between the permanent magnet and the coil is mostly locally coupled, and the magnetic field generated by the permanent magnet does not form a complete closed and efficient magnetic conduction loop. A large number of magnetic lines of force are distributed outside the device or in spatial areas not effectively cut by the coil. Especially when the permanent magnet is located on one side of the rotor and the coil is arranged in a relatively limited area, the magnetic field is prone to leakage into the half-space: that is, a considerable portion of the magnetic field escapes from the side of the permanent magnet away from the coil and away from the effective working area, forming obvious half-space leakage magnetic field; and the leakage magnetic field cannot effectively participate in the magnetic flux change of the coil, ultimately resulting in low magnetic field utilization and insufficient electromechanical coupling efficiency, which in turn reduces the output voltage and output power.

[0004] Existing magnetically levitated electromagnetic energy harvesting devices typically include a non-magnetic or weakly magnetic shell, a reciprocating moving magnet, a fixed magnet, a coil, and a limiting structure. The basic structure is as follows: the coil is wound around the outside of the shell or guide cylinder; the moving magnet is installed inside the shell and can reciprocate axially; a fixed magnet is located at one or both ends of the shell. The fixed magnet and the moving magnet rely on the repulsion of like poles or the attraction of unlike poles to form magnetic levitation support and restoring force. When human movement causes the shell to vibrate, the moving magnet, due to inertia, reciprocates relative to the coil, changing the magnetic flux through the coil and thus inducing electrical energy.

[0005] These magnetic levitation electromagnetic energy harvesting devices utilize the magnetic force between magnets to construct a "magnetic spring," replacing the traditional mechanical spring to provide a restoring force to the moving magnet, allowing it to reciprocate within or near the coil. By adjusting the polarity, spacing, magnetic field strength, and coil placement of the moving and fixed magnets, the system's equivalent stiffness, equilibrium position, and natural frequency can be altered.

[0006] However, existing magnetic levitation electromagnetic energy harvesting devices still have significant defects in low-frequency human motion environments: (1) The device relies on magnetic springs to achieve vibration recovery, and the output efficiency is usually closely related to the matching degree between the system's natural frequency and the external excitation frequency. When the external motion frequency is close to the natural frequency of the magnetic levitation system, the amplitude of the moving magnet is larger and the output power is higher; however, the human motion frequency is generally low and fluctuates unstablely, making it difficult to maintain near the resonant frequency designed by the device for a long time. Therefore, under low-frequency, non-periodic or random motion conditions of the human body, the displacement and velocity of the moving magnet relative to the coil are often small, and the rate of change of magnetic flux is insufficient, ultimately resulting in low induced voltage and output power. (2) The magnetic force between the moving magnet and the fixed magnet changes significantly with the distance, making the equivalent stiffness of the system not constant. Under small human motion, the moving magnet may be restricted to the vicinity of the equilibrium position and can only produce small vibrations; under large impacts or posture changes, the moving magnet is prone to bias, adsorption, collision limit or motion instability, causing discontinuous output waveforms, and even noise and structural damage. (3) Magnetic levitation structures usually require a certain length of travel and the placement of fixed magnets at the ends, making it difficult to further reduce the axial dimension of the device, which is not conducive to its application in wearable devices, portable devices, or confined installation spaces. At the same time, increasing the number of coil turns to increase the output voltage will increase the device size and coil internal resistance, affecting the actual output power; if the number of coil turns is reduced, it is difficult to obtain sufficient induced voltage under low-frequency and low-speed motion. (4) Magnetic levitation structures usually only respond to vibrations along the axial direction, and have limited adaptability to human motion in multiple directions and complex postures. When the direction of human motion is inconsistent with the designed direction of motion of the moving magnet, it is difficult for the moving magnet to generate effective relative displacement, and the energy harvesting efficiency will decrease significantly.

[0007] Therefore, existing magnetic levitation electromagnetic energy harvesting devices suffer from problems such as reliance on magnetic spring resonance, insufficient response under low-frequency human motion, strong nonlinearity, unstable output, limited structural size, and poor directional adaptability. Summary of the Invention

[0008] This invention aims to solve at least one of the technical problems existing in related technologies. To this end, this invention provides a direct-drive energy harvester with self-sensing function for human movement speed, solving the technical problems of existing technologies that rely on magnetic spring resonance and have insufficient response under low-frequency human movement, thus realizing energy harvesting and speed sensing.

[0009] The present invention provides a direct-drive energy harvester with a human motion speed self-sensing function, including a housing and an electromagnetic harvesting unit, a direct-drive excitation input unit and a piezoelectric sensing unit disposed in the housing; The housing includes a first housing, a support plate, and a second housing connected in sequence. The electromagnetic acquisition unit includes a receiving cavity connected to the first housing, a plurality of hollow copper coils axially arranged along the outer wall of the receiving cavity, and a moving part assembly disposed in the receiving cavity and capable of reciprocating along the axial direction. The direct drive excitation input unit includes a non-magnetic through bolt inserted into the mover assembly, a connecting rod disposed on the top of the non-magnetic through bolt, a transmission bearing disposed on the connecting rod, a crankshaft connected to the transmission bearing and the support plate, a second one-way bearing connected to the crankshaft, a driven gear connected to the second one-way bearing, a double gear meshing with the driven gear, a transmission shaft connected to the support plate, a first one-way bearing connected to the transmission shaft, and a driving gear connected to the first one-way bearing. The driving gear meshes with the double gear. The first one-way bearing extends out of the second housing and is connected to a rocker arm. A mass block is disposed at the bottom end of the rocker arm. The piezoelectric sensing unit includes a cantilever beam mounting base connected to the support plate near the side of the second housing, a piezoelectric cantilever beam connected to the cantilever beam mounting base, an end magnet connected to the top of the piezoelectric cantilever beam, and an excitation magnet disposed on the drive gear.

[0010] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the moving part assembly includes multiple magnetic isolation rings and circular magnets arranged alternately in the axial direction, the non-magnetic through bolt passes through the magnetic isolation rings and circular magnets, the top end of the non-magnetic through bolt has a limiting head, the bottom end of the non-magnetic through bolt is screwed with an insulating locking nut, and the multiple magnetic isolation rings and multiple circular magnets are arranged between the limiting head and the insulating locking nut.

[0011] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the support plate is provided with a fitting groove, a magnetic spring mounting seat is inserted in the fitting groove, a magnetic spring is provided on the top surface of the magnetic spring mounting seat, and the magnetic spring is located below the accommodating cavity and corresponds to the non-magnetic through bolt.

[0012] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that multiple winding supports are provided at intervals on the inner wall of the first housing, and the accommodating cavity is connected to the multiple winding supports.

[0013] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that a limiting guide hole is opened at the top of the first housing, a limiting rod is provided at the top of the connecting rod, and the limiting rod passes through the limiting guide hole.

[0014] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the support plate is provided with a bearing mounting seat, the inner wall of the bearing mounting seat is provided with a bearing limiting strip, the outer wall of the second one-way bearing is provided with a bearing guide groove, and the bearing limiting strip is connected to the bearing guide groove.

[0015] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the support plate is provided with a first transmission bearing seat, the second housing is provided with a second transmission bearing seat, and the transmission shaft is connected to the first transmission bearing seat and the second transmission bearing seat.

[0016] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the support plate is provided with a horizontal convex plate on the side corresponding to the second housing, and the cantilever beam fixing seat is detachably connected to the convex plate.

[0017] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the bottom end of the swing arm is provided with a housing, and the mass block is disposed in the housing.

[0018] A further improvement of the direct-drive energy harvester with human motion speed self-sensing function of the present invention is that the outer wall of the second housing is provided with limit bolt one and limit bolt two, which are used to limit the swing position of the swing arm.

[0019] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: By setting up a direct-drive excitation input unit, the human motion or external low-frequency oscillation input is sequentially transmitted through a gear and connecting rod transmission unit consisting of a first one-way bearing, a driving gear, a double gear, and a driven gear, and then through a crankshaft, converting it into the axial reciprocating movement of the mover assembly. This converts low-frequency, discontinuous human motion input into higher-frequency, more regular reciprocating linear motion, increasing the motion frequency of the mover assembly relative to the hollow copper coil, thereby improving the magnetic flux change frequency and induced voltage output capability of the electromagnetic acquisition unit. Compared with linear energy harvesters that rely on flexible coupling driven by magnetic springs, the mover assembly of this invention has a more defined displacement, velocity, and frequency response relationship, which can improve the controllability, repeatability, and response stability of the mover assembly under low-frequency human motion input conditions.

[0020] The mover assembly employs multiple circular magnets and magnetic isolation rings arranged alternately along the axial direction, with the circular magnets arranged in opposite directions to the magnetization of adjacent magnets, thus forming a permanent magnet mover structure with alternating polarities. When the mover assembly reciprocates within the housing cavity, the alternating polarity of the circular magnets causes a periodic change in the magnetic flux passing through the hollow copper coil, increasing the amplitude and regularity of the magnetic flux change in the coil, which is beneficial for enhancing electromagnetic induction output. The movement of the circular magnets and magnetic isolation rings within the hollow copper coil effectively reduces leakage flux loss. Multiple hollow copper coils are arranged sequentially along the axial direction of the housing cavity and connected in series with a wiring polarity matching the arrangement of the circular magnets. This allows the induced voltages generated by each hollow copper coil during the reciprocating movement of the mover assembly to be superimposed in phase at the output terminal, increasing the overall output voltage of the electromagnetic acquisition unit and enhancing its power supply capability to downstream rectification, energy storage, or sensing circuits.

[0021] By using a non-contact piezoelectric sensing unit, the output voltage, output frequency, or output pulse characteristics of the piezoelectric sensing unit can change with the speed of human movement. This enables the energy harvester to collect human movement energy while simultaneously sensing movement speed, thus realizing energy harvesting and speed sensing. This is beneficial for applications in wearable devices, human movement monitoring devices, and self-powered sensing systems.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is an exploded schematic diagram of a direct-drive energy harvester with self-sensing function of human movement speed provided by the present invention.

[0025] Figure 2 This is a three-dimensional schematic diagram of a direct-drive energy harvester with self-sensing function of human movement speed provided by the present invention.

[0026] Figure 3 This is a schematic diagram of the overall structure of a direct-drive energy harvester with human motion speed self-sensing function provided by the present invention, wherein the shell is omitted.

[0027] Figure 4This is a schematic diagram of the overall structure of a direct-drive energy harvester with self-sensing function of human movement speed provided by the present invention, from another perspective, in which the shell is omitted.

[0028] Figure 5 This is a side view of the direct drive excitation input unit in a direct drive energy harvester with human motion speed self-sensing function provided by the present invention.

[0029] Figure 6 This is a cross-sectional view of the electromagnetic harvesting unit in a direct-drive energy harvester with self-sensing function of human movement speed provided by the present invention.

[0030] Figure 7 This is a graph showing the test results of the electromagnetic acquisition unit.

[0031] Figure 8 The image shows the test results for the piezoelectric sensing unit.

[0032] Figure 9 This is a diagram of the magnetic field lines of the moving part.

[0033] Figure 10 This is a diagram showing the results of human gait speed recognition by a piezoelectric sensing unit.

[0034] Figure label: 1. First housing; 2. Receiving cavity; 3. Hollow copper coil; 4. Winding support; 5. Isolating ring; 6. Magnetic isolation ring; 7. Circular magnet; 8. Magnetic spring; 9. Magnetic spring mounting base; 10. Connecting rod; 11. Transmission bearing; 12. Non-magnetic through bolt; 13. Support plate; 14. Bearing mounting base; 15. Crankshaft; 16. Second one-way bearing; 17. Driven gear; 18. Double gear; 19. Driving gear; 20. First one-way bearing; 21. Transmission shaft; 22. End magnet; 23. Piezoelectric cantilever beam; 24. Cantilever beam fixing base; 25. Swing rod; 26. Receiving shell; 27. Mass block; 28. Second housing; 29. ​​Limiting bolt one; 30. Limiting bolt two; 31. Excitation magnet. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0036] The following is combined with Figures 1 to 6The present invention describes a direct-drive energy harvester with a human motion speed self-sensing function, comprising a housing and an electromagnetic harvesting unit, a direct-drive excitation input unit and a piezoelectric sensing unit disposed in the housing. The housing includes a first housing 1, a support plate 13, and a second housing 28 connected in sequence. The electromagnetic acquisition unit includes a receiving cavity 2 connected to the first housing 1, a plurality of hollow copper coils 3 axially arranged along the outer wall of the receiving cavity 2, and a moving part assembly disposed in the receiving cavity 2 and capable of reciprocating along the axial direction. The direct drive excitation input unit includes a non-magnetic through bolt 12 inserted into the mover assembly, a connecting rod 10 disposed on the top of the non-magnetic through bolt 12, a transmission bearing 11 disposed on the connecting rod 10, a crankshaft 15 connected to the transmission bearing 11 and the support plate 13, a second one-way bearing 16 connected to the crankshaft 15, a driven gear 17 connected to the second one-way bearing 16, a double gear 18 meshing with the driven gear 17, a transmission shaft 21 connected to the support plate 13, a first one-way bearing 20 connected to the transmission shaft 21, and a driving gear 19 connected to the first one-way bearing 20. The driving gear 19 meshes with the double gear 18. The first one-way bearing 20 extends out of the second housing 28 and is connected to a rocker arm 25. A mass block 27 is disposed at the bottom end of the rocker arm 25. The piezoelectric sensing unit includes a cantilever beam fixing seat 24 connected to the support plate 13 near the side of the second housing 28, a piezoelectric cantilever beam 23 connected to the cantilever beam fixing seat 24, an end magnet 22 connected to the top end of the piezoelectric cantilever beam 23, and an excitation magnet 31 disposed on the drive gear 19.

[0037] Furthermore, the moving part assembly includes a plurality of magnetic isolation rings 6 and circular magnets 7 arranged alternately in the axial direction. The non-magnetic through bolt 12 passes through the magnetic isolation rings 6 and circular magnets 7. The top end of the non-magnetic through bolt 12 has a limiting head, and the bottom end of the non-magnetic through bolt 12 is screwed with an insulating locking nut. The plurality of magnetic isolation rings 6 and the plurality of circular magnets 7 are arranged between the limiting head and the insulating locking nut.

[0038] When the mover assembly reciprocates axially within the accommodating cavity 2, multiple alternating polarity ring magnets 7 move relative to multiple hollow copper coils 3, causing the magnetic flux through each hollow copper coil 3 to change periodically and inducing voltages in each hollow copper coil 3. The multiple ring magnets 7 are arranged sequentially along the axial direction in a NS / SN / NS / SN / NS / SN pattern, with adjacent ring magnets 7 having opposite magnetization directions, thus forming an alternating polarity permanent magnet mover structure along the axial direction of the mover assembly. The magnetic field lines of the alternating polarity permanent magnet mover structure are as follows: Figure 9 As shown, this spatially alternating magnetic field distribution pattern repeats periodically in the vertical direction. The periodic diverging-converging magnetic field pattern creates an extremely high spatial magnetic field gradient, which significantly enhances the flux alternation rate when the coil dynamically cuts the magnetic field, thereby outputting a higher amplitude induced electromotive force.

[0039] Multiple hollow copper coils 3 are arranged in reverse winding direction and connected in series sequentially by soldering. The inner lead of the first hollow copper coil 3 located at the first axial end serves as a total output terminal of the electromagnetic acquisition unit. The outer lead of the first hollow copper coil 3 is soldered to the outer lead of the second hollow copper coil 3; the inner lead of the second hollow copper coil 3 is soldered to the inner lead of the third hollow copper coil 3. The remaining adjacent hollow copper coils 3 are connected in series step by step according to the rule of alternating connection of outer leads with outer leads and inner leads with inner leads, until the unconnected lead of the last hollow copper coil 3 serves as another total output terminal. Through this wiring method, the wiring polarity of the multiple hollow copper coils 3 matches the alternating polarity arrangement of the multiple ring magnets 7, so that the induced voltage generated by each hollow copper coil 3 during the reciprocating movement of the mover assembly is superimposed in phase at the output terminal, thereby increasing the output voltage of the electromagnetic acquisition unit.

[0040] Furthermore, the support plate 13 has a fitting groove, which is square in shape. A magnetic spring mounting seat 9 is inserted into the fitting groove. A magnetic spring 8 is provided on the top surface of the magnetic spring mounting seat 9. The magnetic spring 8 is located below the accommodating cavity 2 and corresponds to the non-magnetic through bolt 12.

[0041] Furthermore, the inner wall of the first housing 1 is provided with multiple winding supports 4 and isolation rings 5 ​​at intervals. Two adjacent hollow copper coils 3 are axially separated by the winding supports 4 and isolation rings 5. The accommodating cavity 2 is connected to the multiple winding supports 4. Each winding support 4 has a positioning port at a position away from the inner wall of the first housing 1. The accommodating cavity 2 is inserted into each positioning port, thereby achieving stable assembly of the winding part with the first housing 1. At the same time, it can reduce the interference of the metal material of the first housing 1 on the electromagnetic induction process and ensure the acquisition efficiency.

[0042] Furthermore, a limiting guide hole is formed at the top of the first housing 1, and a limiting rod is provided at the top of the connecting rod 10, with the limiting rod passing through the limiting guide hole. By limiting the limiting rod through the limiting guide hole, the radial displacement of the mover assembly during reciprocating motion can be restricted, preventing friction and wear between the mover assembly and the stator winding. Simultaneously, it ensures that the connecting rod 10 always moves in a straight line, improving the stability of the mover assembly's reciprocating motion and ensuring stable energy harvesting efficiency.

[0043] Furthermore, the support plate 13 is provided with a bearing mounting seat 14, the inner wall of the bearing mounting seat 14 is provided with a bearing limiting strip, the outer wall of the second one-way bearing 16 is provided with a bearing guide groove, and the bearing limiting strip is connected to the bearing guide groove to restrict the circumferential rotation of the outer ring of the second one-way bearing 16.

[0044] Furthermore, the support plate 13 has a first transmission bearing seat, the second housing 28 has a second transmission bearing seat, and the transmission shaft 21 is connected to the first transmission bearing seat and the second transmission bearing seat.

[0045] On the inner wall of the support plate 13 and the opposite surface of the second housing 28, multiple first transmission bearing seats are provided along the same axis. Each of the multiple first transmission bearing seats is embedded with a support bearing, which is made of 316 non-magnetic stainless steel. In an electromagnetic power generation environment, the use of non-magnetic stainless steel bearings can completely avoid the internal magnetic circuit interference and magnetic leakage caused by the magnetic conduction of traditional high-carbon steel bearings, ensuring the maximum utilization of magnetic flux. Considering the special application scenario of wearable devices for the lower limbs, 316 stainless steel has excellent corrosion resistance and rust prevention properties, which can effectively resist the erosion of human sweat and complex external environments, significantly extending the mechanical service life of the energy harvester.

[0046] Furthermore, the support plate 13 is provided with a horizontally shaped protrusion on the side corresponding to the second housing 28, and the cantilever beam fixing seat 24 is detachably connected to the protrusion.

[0047] Preferably, the convex plate and the cantilever beam fixing seat 24 are connected by bolts. A slot can be provided on the convex plate, and the cantilever beam fixing seat 24 can be set in an L-shape or an inverted T-shape. Bolts are passed through the cantilever beam fixing seat 24 and the slot, and nuts are tightened and pressed against the bottom surface of the convex plate to fix the cantilever beam fixing seat 24 to the convex plate.

[0048] Preferably, the drive gear 19 has a square mounting slot, and the excitation magnet 31 is embedded and fixed in the square mounting slot to rotate synchronously with the drive gear 19. The motion trajectory of the excitation magnet 31 is arranged adjacent to the end magnet 22; when the drive gear 19 rotates, the excitation magnet 31 periodically passes over the end magnet 22, and through the magnetic coupling between the two, drives the piezoelectric cantilever beam 23 to bend and vibrate non-contactly. Based on the positive piezoelectric effect, during the forced bending deformation process, the piezoelectric material inside the piezoelectric cantilever beam 23 will generate mechanical stress and strain, causing the internal electric dipoles to polarize, and then accumulating opposite charges at the electrodes on its upper and lower surfaces, thereby outputting an alternating voltage signal externally. Subsequently, a Long Short-Term Memory (LSTM) network is used to accurately capture the negative correlation time-series dependence between gait speed and the peak value and peak time interval of the piezoelectric voltage, thereby accurately realizing the self-sensing and recognition of human gait speed. The result of human gait speed recognition is as follows: Figure 10 As shown.

[0049] Furthermore, a housing 26 is provided at the bottom end of the swing arm 25, and the mass block 27 is disposed within the housing 26. The housing 26 is detachably connected to the swing arm 25 by a fastening assembly consisting of bolts and nuts.

[0050] Preferably, the top end of the rocker arm 25 is provided with a convex mating part, and the end of the drive shaft 21 is provided with a concave fitting groove that matches the shape of the convex mating part. The rocker arm 25 forms a transmission connection through the insertion of the convex mating part and the concave fitting groove.

[0051] Furthermore, the outer wall of the second housing 28 is provided with a limiting bolt 29 and a limiting bolt 30, which are used to limit the swing position of the swing arm 25.

[0052] Preferably, the driving gear 19 is mounted on the transmission shaft 21 via the first one-way bearing 20, converting the reciprocating oscillation of the rocker arm 25 into unidirectional rotation of the driving gear 19. The driving gear 19 meshes with the first gear portion of the double gear 18, and the second gear portion of the double gear 18 meshes with the driven gear 17, so that the oscillating kinetic energy of the rocker arm 25 is sequentially transmitted to the driven gear 17 via the transmission shaft 21. The driven gear 17 is coaxially mounted on the outside of the crankshaft 15. The inner wall of the driven gear 17 is provided with a transmission keyway, and the outer circumferential surface of the crankshaft 15 is provided with a corresponding transmission key. The two form a linkage connection for transmitting torque through the keyway of the transmission keyway and the keyway of the transmission key. The transmission keyway of the inner ring of the second one-way bearing 16 is also fixedly connected to the transmission key of the crankshaft 15, so as to constrain the crankshaft 15 to rotate only in one direction, and thus constrain the outer ring of the first one-way bearing 20 to rotate only in one direction through the gear set.

[0053] The connecting rod 10 is fixedly connected to the non-magnetic through bolt 12. When the lower limbs of the human body swing, the swing rod 25 swings, which in turn drives the driving gear 19 to rotate. This rotation, through the double gear 18, reduces speed and increases torque, driving the driven gear 17 to rotate. The driven gear 17 drives the crankshaft 15 to rotate, which in turn drives the connecting rod 10 to move axially back and forth, thus pushing the non-magnetic through bolt 12 to perform linear reciprocating motion. This directly drives the mover assembly to move linearly back and forth along the central axis of the hollow copper coil 3 within the accommodating cavity 2, thereby cutting magnetic field lines and generating an induced electromotive force, thus converting the mechanical energy of the human body's movement into electrical energy output. At the same time, the stroke of the non-magnetic through bolt 12 can be flexibly adjusted by adjusting the installation positions of the first limiting bolt 29 and the second limiting bolt 30 to adapt to the usage requirements of different phase amplitudes. During this movement, the gradient magnetic field array formed by the superposition of multiple circular magnets 7 and magnetic isolation rings 6 periodically cuts the outer hollow copper coil 3. According to Faraday's law of electromagnetic induction, due to the relative displacement of magnetic field lines, the magnetic flux passing through the cross-section of the hollow copper coil 3 undergoes drastic alternating changes over time. This alternating magnetic flux will then induce an electromotive force inside the hollow copper coil 3 and form an induced current in the closed circuit, thereby achieving the efficient conversion of mechanical kinetic energy into electrical energy.

[0054] Furthermore, the driving gear 19 has 45 teeth, the first gear section of the double gear 18 has 19 teeth, the second gear section of the double gear 18 has 45 teeth, and the driven gear 17 has 18 teeth. The pressure angle of each gear is 20°. The gear-connecting rod transmission unit composed of the driving gear 19, the double gear 18, and the driven gear 17 mainly functions to increase the rotational speed, increase the reciprocating frequency of the mover assembly, thereby increasing the peak voltage of the electromagnetic output and improving the efficiency of power collection.

[0055] Figure 7 This graph shows the test results of the electromagnetic acquisition unit under the conditions of 1.4Hz simple harmonic vibration excitation and a swing amplitude of 60 degrees. The test conditions are within the frequency range (1-5Hz) of leg swing during human movement. It can be observed that after 210 minutes of continuous operation, the output voltage waveform and peak amplitude of the electromagnetic acquisition unit did not show significant attenuation, and the generated voltage waveform remained at around 10 volts. The results indicate that the electromagnetic acquisition unit can continuously and reliably capture electromagnetic energy from the environment and maintain a stable output.

[0056] Figure 8This graph shows the test results of the piezoelectric sensing unit under the conditions of 1.4Hz simple harmonic vibration excitation and a swing amplitude of 60 degrees. The test conditions are within the frequency range (1-5Hz) of leg swing during human movement. It can be observed that after 210 minutes of continuous operation, the voltage waveform of the piezoelectric acquisition unit hardly changes, with the peak voltage remaining around 1.5V, fully demonstrating the excellent long-term operational stability of the piezoelectric acquisition unit. The stable output characteristics reflect the reasonable structural design and high operational reliability of the energy harvester, showing no significant performance degradation under long-term continuous operation, further proving its practical value for deployment and long-term service.

[0057] This invention, by setting up a direct-drive excitation input unit, converts human motion or external low-frequency oscillation input into axial reciprocating movement of the mover assembly through a gear and connecting rod transmission unit consisting of a first one-way bearing 20, a driving gear 19, a double gear 18, and a driven gear 17, and a crankshaft 15. This converts low-frequency, discontinuous human motion input into higher-frequency, more regular reciprocating linear motion, increasing the motion frequency of the mover assembly relative to the hollow copper coil 3, thereby improving the magnetic flux change frequency and induced voltage output capability of the electromagnetic acquisition unit. Compared with linear energy harvesters that rely on flexible coupling driven by a magnetic spring 8, the mover assembly of this invention has a more defined displacement, velocity, and frequency response relationship, improving the controllability, repeatability, and response stability of the mover assembly under low-frequency human motion input conditions.

[0058] This invention utilizes a non-contact piezoelectric sensing unit, enabling the output voltage, output frequency, or output pulse characteristics of the piezoelectric sensing unit to change with the speed of human movement. This allows the energy harvester to simultaneously collect human movement energy and sense movement speed, achieving both energy harvesting and speed sensing. This technology is beneficial for applications in wearable devices, human movement monitoring devices, and self-powered sensing systems.

[0059] 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. A direct-drive energy harvester with self-sensing function for human movement speed, characterized in that, It includes a housing and an electromagnetic acquisition unit, a direct drive excitation input unit, and a piezoelectric sensing unit disposed in the housing; The housing includes a first housing, a support plate, and a second housing connected in sequence. The electromagnetic acquisition unit includes a receiving cavity connected to the first housing, a plurality of hollow copper coils axially arranged along the outer wall of the receiving cavity, and a moving part assembly disposed in the receiving cavity and capable of reciprocating along the axial direction. The direct drive excitation input unit includes a non-magnetic through bolt inserted into the mover assembly, a connecting rod disposed on the top of the non-magnetic through bolt, a transmission bearing disposed on the connecting rod, a crankshaft connected to the transmission bearing and the support plate, a second one-way bearing connected to the crankshaft, a driven gear connected to the second one-way bearing, a double gear meshing with the driven gear, a transmission shaft connected to the support plate, a first one-way bearing connected to the transmission shaft, and a driving gear connected to the first one-way bearing. The driving gear meshes with the double gear. The first one-way bearing extends out of the second housing and is connected to a rocker arm. A mass block is disposed at the bottom end of the rocker arm. The piezoelectric sensing unit includes a cantilever beam mounting base connected to the support plate near the side of the second housing, a piezoelectric cantilever beam connected to the cantilever beam mounting base, an end magnet connected to the top of the piezoelectric cantilever beam, and an excitation magnet disposed on the drive gear.

2. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The moving part assembly includes multiple magnetic isolation rings and circular magnets arranged alternately in axial direction. The non-magnetic through bolt passes through the magnetic isolation rings and circular magnets. The top end of the non-magnetic through bolt has a limiting head, and the bottom end of the non-magnetic through bolt is screwed with an insulating lock nut. The multiple magnetic isolation rings and multiple circular magnets are arranged between the limiting head and the insulating lock nut.

3. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 2, characterized in that, The support plate has a fitting groove, and a magnetic spring mounting seat is inserted into the fitting groove. A magnetic spring is provided on the top surface of the magnetic spring mounting seat. The magnetic spring is located below the receiving cavity and corresponds to the non-magnetic through bolt.

4. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The inner wall of the first housing is provided with a plurality of winding supports at intervals, and the accommodating cavity is connected to the plurality of winding supports.

5. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, A limiting guide hole is provided at the top of the first housing, and a limiting rod is provided at the top of the connecting rod, with the limiting rod passing through the limiting guide hole.

6. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The support plate is provided with a bearing mounting seat, and the inner wall of the bearing mounting seat is provided with a bearing limiting strip. The outer wall of the second one-way bearing is provided with a bearing guide groove, and the bearing limiting strip is connected to the bearing guide groove.

7. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The support plate has a first transmission bearing seat, the second housing has a second transmission bearing seat, and the transmission shaft is connected to the first transmission bearing seat and the second transmission bearing seat.

8. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The support plate has a horizontally shaped protrusion on the side corresponding to the second housing, and the cantilever beam fixing seat is detachably connected to the protrusion.

9. A direct-drive energy harvester with self-sensing function for human movement speed as described in claim 1, characterized in that, The bottom end of the swing arm is provided with a housing, and the mass block is disposed inside the housing.

10. A direct-drive energy harvester with self-sensing function for human movement speed according to claim 1, characterized in that, The outer wall of the second housing is provided with a limiting bolt one and a limiting bolt two, which are used to limit the swing position of the swing arm.

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