Variable-stiffness combined type vibration energy feedback device of electric tractor

Abstract

A variable-stiffness combined type vibration energy feedback device of an electric tractor comprises a mechanical electromagnetic energy feedback module, a piezoelectric energy feedback module, an upper box body, a first variable-stiffness spring, an annular ball, a lower box body, a second variable-stiffness spring and a baffle. The top of the upper box body is connected with a battery pack of the electric tractor; the bottom of the lower box body is connected with an electric tractor chassis; the mechanical electromagnetic energy feedback module is arranged in the upper box body; a piezoelectric energy feedback module is mounted in the lower box body; the bottom of the first variable-stiffness spring is arranged on the lower box body, and the top of the first variable-stiffness spring is connected with the upper box body; the upper box body and the lower box body are connected through the annular ball and the baffle, so that the upper box body vibrates up and down relative to the lower box body; the bottom of the second variable stiffness spring is arranged on the piezoelectric energy feedback module, and the top of the second variable stiffness spring is connected with the upper box body. The energy recovery device has the advantages of being continuously variable in inherent frequency of the structure, high in energy recovery efficiency and capable of achieving the damping effect.

Description

Technical Field

[0001] The utility model relates to the technical field of vibration energy recovery of electric vehicles, in particular to a variable-stiffness composite vibration energy feeding device for an electric tractor. Background Technique

[0002] In recent years, electric tractors have become the forefront and hotspots of scientific and technological innovation in new energy agricultural machinery equipment. However, due to the relatively slow development of high specific power and high specific energy battery technologies, electric tractors restricted by battery performance generally have application difficulties such as insufficient power. The driving environment of electric tractors is usually field dirt roads, rural roads, gravel roads, etc., and the road surface excitation has characteristics of randomness, wide frequency band, and large amplitude. Therefore, an electric tractor vibration energy feeding device with a wide adaptability frequency band and high energy feeding efficiency is needed to convert the lost vibration energy into electric energy to charge the power battery, thereby improving the endurance mileage of the electric tractor.

[0003] At present, the vibration energy feeding devices of electric vehicles are mainly mechanical or piezoelectric structures, and most of them only adopt a single energy conversion mechanism, with relatively low energy feeding efficiency. At the same time, the traditional single-frequency vibration energy feeding system only has a high energy feeding efficiency when the road surface excitation frequency is near the natural frequency of the system. Therefore, the utility model utilizes the stiffness change characteristics during the vibration of the variable-stiffness spring, takes the shock absorption strategy of the battery pack as a constraint, continuously broadens the natural frequency range of the energy feeding system, and improves the adaptability of the energy feeding system in a multi-frequency vibration environment; and combines the mechanical electromagnetic structure and the piezoelectric structure to improve the energy feeding efficiency. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the utility model is to provide a variable-stiffness composite vibration energy feeding device for an electric tractor, which has the characteristics of a broadened energy feeding frequency band, a compact and reliable structure, a high energy recovery efficiency, and a shock absorption effect.

[0005] In order to achieve the above purpose, the technical scheme adopted by the utility model is:

[0006] A variable-stiffness composite vibration energy feeding device for an electric tractor includes a mechanical electromagnetic energy feeding module, a piezoelectric energy feeding module, an upper box body, a first variable-stiffness spring, an annular ball, a lower box body, a second variable-stiffness spring, and a baffle; the top of the upper box body is used to connect the battery pack of the electric tractor; the bottom of the lower box body is connected to the electric tractor chassis;

[0007] The mechanical electromagnetic energy feeding module is installed on the upper box body; the piezoelectric energy feeding module is installed inside the lower box body; the bottom of the first variable stiffness spring is arranged on the lower box body, and the top is connected to the upper box body; the ring surface of the annular ball is vertical, the baffle is a vertical baffle, and the upper box body and the lower box body are connected by the annular ball and the baffle, so that the upper box body can vibrate up and down relative to the lower box body; the bottom of the second variable stiffness spring is arranged on the piezoelectric energy feeding module, and the top is connected to the upper box body.

[0008] In one embodiment, both the first variable stiffness spring and the second variable stiffness spring are variable pitch springs; the bottom of the first variable stiffness spring is installed on the fifteenth connecting rod of the lower box body, and the top is connected to the ninth connecting rod of the upper box body. The bottom of the second variable stiffness spring is arranged on the upper cover plate of the piezoelectric energy feeding module, and the top is connected to the ninth connecting rod of the upper box body.

[0009] In one embodiment, the upper box body includes a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a sixth connecting rod, a seventh connecting rod, an eighth connecting rod, a ninth connecting rod, a fifth connecting rod, a tenth connecting rod, a deep groove ball bearing, a first bearing seat, a second bearing seat, and a third bearing seat; each connecting rod is a rectangular hollow steel pipe. The first connecting rod and the fourth connecting rod are arranged below the seventh connecting rod and are used to fix the two ends of the second connecting rod and the third connecting rod; the fifth connecting rod and the tenth connecting rod are arranged between the two fourth connecting rods and are respectively used to install the first bearing seat and the third bearing seat; both ends of the second bearing seat are installed on the fifth connecting rod and the tenth connecting rod respectively; the sixth connecting rod is used to connect and fix the fifth connecting rod and the tenth connecting rod; the seventh connecting rod and the eighth connecting rod are connected end to end, and the ninth connecting rod is arranged on the seventh connecting rod and is used to connect the battery pack of the electric tractor; the deep groove ball bearing is installed on the first bearing seat, the second bearing seat, and the third bearing seat and is respectively used to install the gear shaft and the second bevel gear shaft.

[0010] In one embodiment, the lower box body includes an eleventh connecting rod, a twelfth connecting rod, a thirteenth connecting rod, a fourteenth connecting rod, a fifteenth connecting rod, a sixteenth connecting rod, a seventeenth connecting rod, an eighteenth connecting rod, a nineteenth connecting rod, a twentieth connecting rod, a twenty-first connecting rod, a twenty-second connecting rod, and a twenty-third connecting rod; each connecting rod is a rectangular hollow steel pipe. The twenty-third connecting rod and the twelfth connecting rod are connected end to end to form the bottom of the lower box body, and the eighteenth connecting rod and the nineteenth connecting rod are connected end to end to form the top of the lower box body; the eleventh connecting rod and the fourteenth connecting rod are arranged at the bottom of the lower box body for connecting the top of the lower box body; the thirteenth connecting rod, the fifteenth connecting rod, and the sixteenth connecting rod are arranged on the twelfth connecting rod at the bottom of the lower box body, wherein the thirteenth connecting rod and the fifteenth connecting rod are used for installing the lower bottom plate of the piezoelectric energy harvesting module; both ends of the seventeenth connecting rod are arranged on the sixteenth connecting rod for fixing the bottom of the twenty-second connecting rod; one end of the twenty-first connecting rod is arranged on the twentieth connecting rod and the other end is used for fixing the back of the twenty-second connecting rod; the twenty-second connecting rod is used for installing a rack.

[0011] In one embodiment, the mechanical electromagnetic energy harvesting module includes a gear shaft, a rack, a first bevel gear, a second bevel gear, a second bevel gear shaft, a third bevel gear, a first one-way clutch, a second one-way clutch, a coupling, and a DC generator; both ends of the gear shaft of the mechanical electromagnetic energy harvesting module are installed inside the first bearing seat and the third bearing seat through deep groove ball bearings; the second bevel gear shaft is installed inside the second bearing seat through the deep groove ball bearing; the rack meshes with the gear shaft, the lower end of the rack is fixed to the seventeenth connecting rod of the lower box body, and the back is fixed to the twenty-second connecting rod of the lower box body; the first bevel gear and the third bevel gear are installed on the gear shaft through the first one-way clutch and the second one-way clutch, and both of them mesh with the second bevel gear at the same time; the second bevel gear shaft is connected to the DC generator through the coupling.

[0012] In one embodiment, the piezoelectric energy harvesting module includes a protection plate, shock-absorbing springs, an upper cover plate, long columns, a fulcrum, a lower bottom plate, a lever, short columns, a piezoelectric substrate, piezoelectric ceramics, and buffer springs; the piezoelectric energy harvesting module is installed on the thirteenth connecting rod and the fifteenth connecting rod of the lower box body; the upper cover plate, the lower bottom plate, and the protection plate are all rectangular steel plates, and the lower bottom plate is connected to the protection plate; the bottom of the upper cover plate is connected to the protection plate through shock-absorbing springs, enabling the upper cover plate to vibrate up and down reciprocally; the piezoelectric substrate is installed between the long columns and the short columns, and the piezoelectric ceramics are arranged on the piezoelectric substrate; the fulcrum is arranged at the 1 / 3 groove at the bottom of the lever, and the lever can rotate up and down along the fulcrum; the bottom of the long column is hinged to the lever for triggering the lever to rotate downward; the short column is arranged on the lever for driving the piezoelectric substrate to rotate upward and compress the buffer spring; the bottom of the buffer spring is arranged on the short column, and the top is connected to the bottom of the upper cover plate.

[0013] In one embodiment, the annular ball includes a guide rail, balls, and a base. The balls are installed in the guide rail and rotate along the guide rail. The guide rail is installed on the base, and the base is installed on the upper box body.

[0014] In one embodiment, the baffle is arranged on the lower box body and is connected to the annular ball, enabling the annular ball to roll up and down along the baffle.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] 1. The device of the present utility model can convert the vibration energy generated during the driving process of an electric tractor into electrical energy to provide electrical energy supply for the power battery to extend the cruising range of the electric tractor.

[0017] 2. The stiffness of the device of the present utility model can be changed, so that while meeting the shock absorption requirements, a relatively wide intersection is generated between the natural frequency range of the device and the road surface excitation frequency band range, realizing the improvement of the energy harvesting efficiency.

[0018] 3. The device of the present utility model has a wide energy harvesting frequency band, is structurally compact and reliable, has a high energy harvesting efficiency, fast response, reliable structure, and convenient layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the present utility model.

[0020] Figure 2 It is a front view of the structure of the present utility model.

[0021] Figure 3 It is a schematic diagram of the variable stiffness spring of the present utility model.

[0022] Figure 4This is a schematic structural diagram of the mechanical electromagnetic energy feeding module of the present utility model.

[0023] Figure 5 This is a structural sectional view of the piezoelectric energy feeding module of the present utility model.

[0024] Figure 6 This is a schematic structural diagram of the upper box body of the present utility model.

[0025] Figure 7 This is a schematic structural diagram of the lower box body of the present utility model.

[0026] In the attached drawings, the components represented by each reference numeral are as follows: mechanical electromagnetic energy feeding module A, piezoelectric energy feeding module B, upper box body 1, first variable stiffness spring 2, annular ball 3, lower box body 4, second bearing seat 5, baffle 6, second variable stiffness spring 7, first bearing seat 8, first bevel gear 9, gear shaft 10, third bevel gear 11, third bearing seat 12, protection plate 13, shock-absorbing spring 14, upper cover plate 15, first one-way clutch 16, coupling 17, DC generator 18, second bevel gear shaft 19, second bevel gear 20, second one-way clutch 21, rack 22, long column 23, fulcrum 24, lower bottom plate 25, lever 26, short column 27, piezoelectric substrate 28, piezoelectric ceramic 29, buffer spring 30, first connecting rod 31, second connecting rod 32, guide rail 33, ball 34, base 35, third connecting rod 36, fourth connecting rod 37, fifth connecting rod 38, sixth connecting rod 39, seventh connecting rod 40, eighth connecting rod 41, ninth connecting rod 42, tenth connecting rod 43, deep groove ball bearing 44, eleventh connecting rod 45, twelfth connecting rod 46, thirteenth connecting rod 47, fourteenth connecting rod 48, fifteenth connecting rod 49, sixteenth connecting rod 50, seventeenth connecting rod 51, eighteenth connecting rod 52, nineteenth connecting rod 53, twentieth connecting rod 54, twenty-first connecting rod 55, twenty-second connecting rod 56 and twenty-third connecting rod 57. Detailed implementation manners

[0027] The implementation manners of the present utility model will be described in detail below with reference to the attached drawings and embodiments.

[0028] Refer to Figures 1 to 7 As shown, a variable stiffness composite type electric tractor vibration energy feeding device mainly consists of the following parts: mechanical electromagnetic energy feeding module A, piezoelectric energy feeding module B, upper box body 1, first variable stiffness spring 2, annular ball 3, lower box body 4, second variable stiffness spring 7 and baffle 6.

[0029] The top of the upper box body 1 is used to connect the battery pack of the electric tractor. Specifically, the ninth connecting rod 42 of the upper box body 1 is connected to the lithium battery pack of the electric tractor through a hinge.

[0030] The bottom of the lower box body 4 is connected to the chassis of the electric tractor. Specifically, the twenty-third connecting rod 57 of the lower box body 4 is connected to the chassis of the electric tractor by a hinge.

[0031] The mechanical electromagnetic energy feeding module A is installed on the upper box body 1, and the piezoelectric energy feeding module B is installed inside the lower box body 4; the bottom of the first variable stiffness spring 2 is arranged on the lower box body 4, and the top is connected to the upper box body 1; the annular surface of the annular ball 3 is vertical, the baffle 6 is a vertical baffle, and the upper box body 1 and the lower box body 4 are connected by the annular ball 3 and the baffle 6, so that the upper box body 1 can vibrate up and down relative to the lower box body 4. The bottom of the second variable stiffness spring 7 is arranged on the upper cover plate 15 of the piezoelectric energy feeding module B, and the top is connected to the upper box body 1, and specifically can be connected to the aforementioned ninth connecting rod 42.

[0032] The upper box body 1 can be used to support and accommodate other components, which mainly include the first connecting rod 31, the second connecting rod 32, the third connecting rod 36, the fourth connecting rod 37, the sixth connecting rod 39, the seventh connecting rod 40, the eighth connecting rod 41, the ninth connecting rod 42, the fifth connecting rod 38, the tenth connecting rod 43, the deep groove ball bearing 44, the first bearing seat 8, the second bearing seat 5 and the third bearing seat 12, etc. Each of the connecting rods is a rectangular hollow steel pipe. The first connecting rod 31 and the fourth connecting rod 37 are located at the bottom of the upper box body 1, and their main function is to provide fixed points for the second connecting rod 32 and the third connecting rod 36, playing a role in supporting and stabilizing the entire structure. The two ends of the second connecting rod 32 and the third connecting rod 36 are respectively fixed on the first connecting rod 31 and the fourth connecting rod 37, and can be used to connect and support other components. The fifth connecting rod 38 and the tenth connecting rod 43 are located between the fourth connecting rods 37, and their main function is to install the first bearing seat 8 and the third bearing seat 12. The bearing seats are used to support and fix the bearings, reduce friction, and allow other components to rotate. The two ends of the second bearing seat 5 are respectively installed on the fifth connecting rod 38 and the tenth connecting rod 43, and can be used to support and fix the rotating parts. The sixth connecting rod 39 is used to connect and fix the fifth connecting rod 38 and the tenth connecting rod 43, enhancing the stability of the entire structure. The seventh connecting rod 40 and the eighth connecting rod 41 are connected end to end, used to construct a frame or support structure, and the ninth connecting rod 42 is arranged on the seventh connecting rod 40, and its function is to connect the battery pack of the electric tractor. The deep groove ball bearing 44 is installed on the first bearing seat 8, the second bearing seat 5 and the third bearing seat 12, and is used to install the gear shaft 10 and the second bevel gear shaft 19. The deep groove ball bearing can bear radial loads and bidirectional axial loads, and is suitable for applications with high speeds or even extremely high speeds. The gear shaft 10 and the second bevel gear shaft 19 are installed on the corresponding bearing seats through the deep groove ball bearing 44, and can be used to transmit power and change the speed or torque.

[0033] The lower box body 4 is the lower half of the entire mechanical structure and is composed of multiple connecting rods, which can be used to support and fix other mechanical components. It mainly includes the eleventh connecting rod 45, the twelfth connecting rod 46, the thirteenth connecting rod 47, the fourteenth connecting rod 48, the fifteenth connecting rod 49, the sixteenth connecting rod 50, the seventeenth connecting rod 51, the eighteenth connecting rod 52, the nineteenth connecting rod 53, the twentieth connecting rod 54, the twenty-first connecting rod 55, the twenty-second connecting rod 56, and the twenty-third connecting rod 57. Each connecting rod is a rectangular hollow steel pipe. Among them, the eleventh connecting rod 45 and the fourteenth connecting rod 48 are located at the bottom of the lower box body 4, and their main function is to connect the top of the lower box body 4, which helps to provide structural stability. The twenty-third connecting rod 57 is connected end to end with the twelfth connecting rod 46 to form the bottom frame of the lower box body 4, which can be used to support the weight of the entire lower box body and provide fixed points for other connecting rods. The eighteenth connecting rod 52 is connected end to end with the nineteenth connecting rod 53 to form the top frame of the lower box body 4, which can be used to fix and support the upper box body 1 or other mechanical components. The thirteenth connecting rod 47, the fifteenth connecting rod 49, and the sixteenth connecting rod 50 are arranged on the twelfth connecting rod 46 at the bottom of the lower box body 4. The thirteenth connecting rod 47 and the fifteenth connecting rod 49 are used to install the lower bottom plate 25 of the piezoelectric energy harvesting module B. Both ends of the seventeenth connecting rod 51 are arranged on the sixteenth connecting rod 50 and are used to fix the bottom of the twenty-second connecting rod 56 to keep the position of the twenty-second connecting rod 56 stable. One end of the twenty-first connecting rod 55 is arranged on the twentieth connecting rod 54, and the other end is used to fix the back of the twenty-second connecting rod 56 to further stabilize the twenty-second connecting rod 56 and ensure its correct installation. The twenty-second connecting rod 56 is used to install the rack 22. The lower bottom plate 25 of the piezoelectric energy harvesting module B is installed on the thirteenth connecting rod 47 and the fifteenth connecting rod 49, which can be used to convert mechanical energy into electrical energy and can be used for vibration control and energy harvesting.

[0034] According to the above structure, a more specific installation method of the first variable stiffness spring 2 of the present utility model is that its bottom is installed on the fifteenth connecting rod 49 of the lower box body 4, and the top is connected to the ninth connecting rod 42 of the upper box body 1.

[0035] The piezoelectric energy harvesting module B is used to convert mechanical energy into electrical energy, and mainly includes a protection plate 13, a shock-absorbing spring 14, an upper cover plate 15, a long column 23, a fulcrum 24, a lower bottom plate 25, a lever 26, a short column 27, a piezoelectric substrate 28, a piezoelectric ceramic 29 and a buffer spring 30. The protection plate 1 is a rectangular steel plate that can protect the internal components of the piezoelectric energy harvesting module B from the external environment. The shock-absorbing spring 14 is connected between the upper cover plate 15 and the protection plate 13, allowing the upper cover plate 15 to vibrate up and down reciprocally. The shock-absorbing spring 14 can be used to reduce the impact of vibration on the upper cover plate 15 while maintaining the frequency and amplitude of vibration. The upper cover plate 15 is another rectangular steel plate located at the top of the piezoelectric energy harvesting module B. Connected to the protection plate 13 through the shock-absorbing spring 14, the vibration of the upper cover plate 15 is a key part of the energy conversion process. The long column 23 and the short column 27 are used to support and fix the piezoelectric substrate 28. The bottom of the long column 23 is hinged to the lever 26, and the short column 27 is arranged on the lever 26, and the two work together to achieve the conversion of mechanical energy into electrical energy. The fulcrum 24 is set in the groove at the bottom 1 / 3 of the lever 26 and is the center point of rotation of the lever 26. The lever 26 can rotate up and down along the fulcrum 24, and its design may be used to amplify or transmit force. The bottom of the long column 23 is hinged to the lever 26, triggering the lever 26 to rotate downward, thereby driving the piezoelectric substrate 28. The piezoelectric substrate 28 is installed between the long column 23 and the short column 27 and is used to support the piezoelectric ceramic 29. The piezoelectric substrate 28 can be made of a material with high elasticity and durability. The piezoelectric ceramic 29 set on the piezoelectric substrate 28 is the key element for energy conversion. When the piezoelectric ceramic is subjected to mechanical pressure, it will generate electric charges, realizing the conversion of mechanical energy into electrical energy. The bottom of the buffer spring 30 is set on the short column 27, and the top is connected to the bottom of the upper cover plate 15, which can provide power when the piezoelectric substrate 28 rotates upward, store energy when compressed, and then help restore the original position when released. The lower bottom plate 25 is connected to the protection plate 13 to form the bottom support of the piezoelectric energy harvesting module B. It is installed on the thirteenth connecting rod 47 and the fifteenth connecting rod 49 of the lower box body 4 to ensure the stability of the entire module.

[0036] In the piezoelectric energy harvesting module B of the present utility model, when the upper cover plate 15 vibrates up and down reciprocally due to external vibration, through the amplification of the shock-absorbing spring 14 and the lever 26, the piezoelectric substrate 28 and the piezoelectric ceramic 29 are driven to generate electrical energy.

[0037] The mechanical electromagnetic energy feeding module A is used to convert mechanical energy into electrical energy. It mainly includes a gear shaft 10, a rack 22, a first bevel gear 9, a second bevel gear 20, a second bevel gear shaft 19, a third bevel gear 11, a first one-way clutch 16, a second one-way clutch 21, a coupling 17 and a DC generator 18. The two ends of the gear shaft 10 are installed inside the first bearing block 8 and the third bearing block 12 through deep groove ball bearings 44, allowing the gear shaft 10 to rotate smoothly. The rack 22 meshes with the gear shaft 10 and is used to convert the rotational motion of the gear into a linear motion. The lower end of the rack 22 is fixed to the seventeenth connecting rod 51 of the lower box body 4, and the back is fixed to the twenty-second connecting rod 56 of the lower box body 4 to ensure the stability and correct positioning of the rack 22. The first bevel gear 9 and the third bevel gear 11 are installed on the gear shaft 10 through the first one-way clutch 16 and the second one-way clutch 21. The one-way clutch allows the gear to rotate in a single direction and locks in the opposite direction. The second bevel gear 20 meshes with the first bevel gear 9 and the third bevel gear 11 and is installed on the second bevel gear shaft 19. The second bevel gear shaft 19 is installed inside the second bearing block 5 through a deep groove ball bearing 44 to support the rotation of the second bevel gear 20. The first one-way clutch 16 and the second one-way clutch 21 are installed on the gear shaft 10 and are used in conjunction with the first bevel gear 9 and the third bevel gear 11 to control the rotation direction of the gear, which can be used to optimize the energy conversion efficiency. The coupling 17 is used to connect two rotating shafts and allows them to rotate synchronously. In this system, the coupling 17 connects the second bevel gear shaft 19 to the DC generator 18. The DC generator 18 is the electromagnetic part of the module and is used to convert mechanical energy into electrical energy. Through the coupling 17, the rotation of the second bevel gear shaft 19 drives the DC generator 18 to generate current.

[0038] The mechanical electromagnetic energy feeding module A of the present utility model converts mechanical energy into electrical energy through a series of mechanical transmission elements (such as gears, racks, bevel gears and couplings). The design of the module allows the control of the energy flow direction through the one-way clutch to optimize the energy conversion efficiency. The DC generator 18, as the core component of energy conversion, converts mechanical rotational energy into electrical energy for use by other systems.

[0039] The annular ball 3 can be used to achieve smooth linear or rotational motion. It includes a guide rail 33, balls 34, and a base 35. The balls 34 are installed inside the guide rail 33 and are usually made of hardened steel or plastic, which can reduce friction and improve the smoothness of motion. The balls 34 can rotate along the guide rail 33 to achieve smooth linear or rotational motion. The guide rail 33 is installed on the base 35, providing a stable rolling path for the balls 34. The base 35 is installed on the second connecting rod 32 and the third connecting rod 36 of the upper box body 1. The function of the base 35 is to fix the position of the guide rail 33, ensuring the stability and reliability of the annular ball 3. When the base 35 is fixed at a specific position on the upper box body 1, the annular ball 3 can be used to support the moving parts, reduce friction, and improve the efficiency and accuracy of motion.

[0040] The baffle 6 is arranged on the fourteenth connecting rod 48 of the lower box body 4 and is connected to the annular ball 3, enabling the annular ball 3 to roll up and down along the baffle 6.

[0041] In this embodiment, both the upper box body and the lower box body are welded by square steel of different sizes.

[0042] To facilitate the understanding of the working process of the device of the present utility model, the working process of the present utility model is described as follows:

[0043] Figure 1 In the above, the first bearing seat 8, the second bearing seat 5, and the third bearing seat 12 are fixedly connected to the upper box body through hinges. One end of the gear shaft 10 is installed inside the first bearing seat 8 through a deep groove ball bearing 44, and the other end is installed inside the third bearing seat 12; the second bevel gear 20 is installed inside the second bearing seat through a deep groove ball bearing 44; the back of the rack 22 is fixed to the twenty-second connecting rod 56 of the lower box body 4; the first variable stiffness spring 2 is fixed between the upper and lower box bodies, and the second variable stiffness spring 7 is fixed between the ninth connecting rod 42 of the upper box body 1 and the upper cover plate 15, providing a restoring force for the upward vibration of the upper box body 1.

[0044] Figure 2 In the above, A is the mechanical electromagnetic energy harvesting module, and B is the piezoelectric energy harvesting module; the annular ball 3 is installed on the upper box body 1, and the baffle 6 is welded to the fourteenth connecting rod 48 of the lower box body 4. The upper box body 1 can vibrate up and down along the baffle 6 through the annular ball 3.

[0045] Figure 3 In the above, both the first variable stiffness spring 2 and the second variable stiffness spring 7 are variable pitch springs, having the property of a non-linear gradually stiffening spring. With the relative movement between the upper box body 1 and the lower box body 4, the stiffness of the first variable stiffness spring 2 and the second variable stiffness spring 7 non-linearly increases or decreases, thereby changing the overall stiffness and natural frequency of the device.

[0046] Figure 4The gear shaft 10 moves up and down with the upper housing 1, meshes with the rack 22, and then power is input to the gear shaft 10; due to the action of the first one-way clutch 16 and the second one-way clutch 21 installed in the first bevel gear 9 and the third bevel gear 11, the gear shaft 10 transmits power in only one direction, and the other rotation direction is idling; when the upper housing moves downward, the first bevel gear 9 acts as a driving wheel to transmit power to the second bevel gear 20; when the upper housing moves upward, the third bevel gear 11 acts as a driving wheel to transmit power to the second bevel gear 20; therefore, the second bevel gear 20 always rotates in one direction, thereby driving the generator 18 to continuously work and generate electrical energy through the coupling 17.

[0047] Figure 5 The shock absorbing spring 14 is fixed between the upper cover plate 15 and the protective plate 13, and the upper cover plate can vibrate up and down; the upper end surface of the long column 23 is in contact with the upper cover plate 15, and when the upper cover plate 15 vibrates downward, the left end of the lever 26 is driven to rotate downward along the fulcrum 24, and the right end of the lever 26 drives the short column 27 to move upward. In this process, the piezoelectric matrix 28 is bent and deformed upward, driving the piezoelectric ceramic 29 to deform, thereby causing the piezoelectric effect to generate electrical energy; the buffer spring 30 is a lightweight spring, which is used to absorb part of the vibration to improve the safety of the device, and provide a restoring force to quickly restore the lever 26 to a balanced position.

[0048] By rationally designing the stiffness range of the variable stiffness spring in the utility model device, the road excitation frequency range of the electric tractor during the common speed driving process is highly overlapped with the natural frequency range of the device, and the device realizes efficient energy feeding. Part of the vibration energy generated during the driving of the electric tractor is input into the mechanical electromagnetic module, and the power is output to the generator to generate electrical energy through the gear rack transmission, the first bevel gear, the second bevel gear and the third bevel gear transmission; the other part is transmitted to the piezoelectric energy feeding module, which drives the long column to rotate through the upper cover plate, and transmits the power to the left end of the lever, and then the right end of the lever drives the short column to move upward, so that the piezoelectric ceramic is deformed to produce a piezoelectric effect, and finally outputs electrical energy; its electrical energy and the electrical energy generated by the mechanical electromagnetic energy feeding module are finally combined to charge the power battery.

[0049] According to the up and down bidirectional vibration of the vehicle body, the movement of the upper box is divided into downstroke and upstroke:

[0050] Downward stroke: During the downward movement of the upper box body 1, the compression amounts of the first variable stiffness spring 2 and the second variable stiffness spring 7 increase, and the stiffness increases; the gear shaft 10 meshes with the rack 22, and the gear shaft rotates clockwise. At this time, the first bevel gear 9 serves as the driving wheel and transmits power to the second bevel gear 20 through bevel gear transmission. The second bevel gear 20 rotates counterclockwise at this time. Finally, the second bevel gear 20 drives the generator 18 to rotate counterclockwise through the coupling 17 to generate electric energy; on the other hand, power is transmitted to the upper cover plate 15 through the second variable stiffness spring 7. At this time, both the second variable stiffness spring 7 and the shock-absorbing spring 14 are in a compressed state. Then the upper cover plate drives the long column to rotate, transmits power to the left end of the lever, and causes the lever 26 to rotate downward along the fulcrum 24. Then the right end of the lever drives the short column to move upward, so that the piezoelectric ceramic deforms to generate the piezoelectric effect and finally generates electric energy.

[0051] Upward stroke: During the upward movement of the upper box body 1, the compression amounts of the first variable stiffness spring 2 and the second variable stiffness spring 7 decrease, and the stiffness decreases; the gear shaft 10 meshes with the rack 22, and the gear shaft 10 rotates counterclockwise. At this time, the third bevel gear 11 serves as the driving wheel and transmits power to the second bevel gear 20 through bevel gear transmission. The second bevel gear drives the generator to work to generate electric energy through the coupling; on the other hand, during the upward movement of the upper box body 1, both the second variable stiffness spring 7 and the shock-absorbing spring 14 are in a recovery state. The shock-absorbing spring 14 exerts a recovery force on the upper cover plate 15 to make the upper cover plate move upward, and the buffer spring 30 is also in a recovery state. During the upward movement of the upper cover plate 15, a recovery force is applied to the right end of the lever to make the lever 26 return to the balanced state. At the same time, the piezoelectric substrate and the piezoelectric ceramic also return to the balanced position.

Claims

1. A variable stiffness composite electric tractor vibration energy feedback device, characterized in that: The invention comprises a mechanical electromagnetic energy feeding module (A), a piezoelectric energy feeding module (B), an upper box (1), a first variable stiffness spring (2), an annular ball (3), a lower box (4), a second variable stiffness spring (7) and a baffle (6); the top of the upper box (1) is used to connect to a battery pack of an electric tractor; the bottom of the lower box (4) is connected to a chassis of the electric tractor; the first variable stiffness spring (2) and the second variable stiffness spring (7) are both variable pitch springs; The mechanical electromagnetic energy feeding module (A) is installed on the upper box (1); the piezoelectric energy feeding module (B) is installed inside the lower box (4); the bottom of the first variable stiffness spring (2) is arranged on the lower box (4), and the top is connected to the upper box (1); the annular surface of the annular ball (3) is vertical, and the baffle (6) is a vertical baffle; the upper box (1) and the lower box (4) are connected through the annular ball (3) and the baffle (6), so that the upper box (1) can vibrate up and down relative to the lower box (4); the bottom of the second variable stiffness spring (7) is arranged on the piezoelectric energy feeding module (B), and the top is connected to the upper box (1).

2. The variable stiffness composite electric tractor vibration energy feedback device according to claim 1, characterized in that: The bottom of the first variable stiffness spring (2) is installed on the fifteenth connecting rod (49) of the lower box (4), and the top is connected to the ninth connecting rod (42) of the upper box (1); the bottom of the second variable stiffness spring (7) is arranged on the upper cover plate (15) of the piezoelectric energy feeding module (B), and the top is connected to the ninth connecting rod (42) of the upper box (1).

3. The variable stiffness composite electric tractor vibration energy feedback device according to claim 1, characterized in that: The upper box body (1) comprises a first connecting rod (31), a second connecting rod (32), a third connecting rod (36), a fourth connecting rod (37), a sixth connecting rod (39), a seventh connecting rod (40), an eighth connecting rod (41), a ninth connecting rod (42), a fifth connecting rod (38), a tenth connecting rod (43), a deep groove ball bearing (44), a first bearing seat (8), a second bearing seat (5) and a third bearing seat (12); each connecting rod is a rectangular hollow steel pipe, the first connecting rod (31) and the fourth connecting rod (37) are arranged below the seventh connecting rod (40) to fix the two ends of the second connecting rod (32) and the third connecting rod (36); the fifth connecting rod (38) and the tenth connecting rod (43) are arranged The first bearing seat (8) and the third bearing seat (12) are respectively mounted between the two fourth connecting rods (37); the two ends of the second bearing seat (5) are respectively mounted on the fifth connecting rod (38) and the tenth connecting rod (43); the sixth connecting rod (39) is used to connect and fix the fifth connecting rod (38) and the tenth connecting rod (43); the seventh connecting rod (40) and the eighth connecting rod (41) are connected end to end; the ninth connecting rod (42) is arranged on the seventh connecting rod (40) and is used to connect the battery pack of the electric tractor; the deep groove ball bearing (44) is mounted on the first bearing seat (8), the second bearing seat (5) and the third bearing seat (12), and is respectively used to mount the gear shaft (10) and the second bevel gear shaft (19).

4. The variable stiffness composite electric tractor vibration energy feedback device according to claim 3, characterized in that: The lower box body (4) comprises an eleventh connecting rod (45), a twelfth connecting rod (46), a thirteenth connecting rod (47), a fourteenth connecting rod (48), a fifteenth connecting rod (49), a sixteenth connecting rod (50), a seventeenth connecting rod (51), an eighteenth connecting rod (52), a nineteenth connecting rod (53), a twentieth connecting rod (54), a twenty-first connecting rod (55), a twenty-second connecting rod (56) and a twenty-third connecting rod (57); each connecting rod is a rectangular hollow steel pipe, the twenty-third connecting rod (57) and the twelfth connecting rod (46) are connected end to end to form the bottom of the lower box body (4), the eighteenth connecting rod (52) and the nineteenth connecting rod (53) are connected end to end to form the top of the lower box body (4); the eleventh connecting rod (45) and the tenth connecting rod (51) are connected end to end to form the top of the lower box body (4); Four connecting rods (48) are arranged at the bottom of the lower box body (4) for connecting the top of the lower box body (4); the thirteenth connecting rod (47), the fifteenth connecting rod (49) and the sixteenth connecting rod (50) are arranged on the twelfth connecting rod (46) at the bottom of the lower box body (4), wherein the thirteenth connecting rod (47) and the fifteenth connecting rod (49) are used to install the lower base plate (25) of the piezoelectric energy feeding module (B); both ends of the seventeenth connecting rod (51) are arranged on the sixteenth connecting rod (50) for fixing the bottom of the twenty-second connecting rod (56); one end of the twenty-first connecting rod (55) is arranged on the twentieth connecting rod (54), and one end is used to fix the back of the twenty-second connecting rod (56); the twenty-second connecting rod (56) is used to install the rack (22).

5. The variable stiffness composite electric tractor vibration energy feedback device according to claim 4, characterized in that: The mechanical electromagnetic energy feeding module (A) comprises a gear shaft (10), a rack (22), a first bevel gear (9), a second bevel gear (20), a second bevel gear shaft (19), a third bevel gear (11), a first one-way clutch (16), a second one-way clutch (21), a coupling (17) and a DC generator (18); both ends of the gear shaft (10) of the mechanical electromagnetic energy feeding module (A) are mounted inside the first bearing seat (8) and the third bearing seat (12) via deep groove ball bearings (44); the second bevel gear shaft (19) is mounted inside the third bevel gear shaft (11) via the deep groove ball bearings (44); The rack (22) is meshed with the gear shaft (10), the lower end of the rack (22) is fixed to the seventeenth connecting rod (51) of the lower housing (4), and the back end is fixed to the twenty-second connecting rod (56) of the lower housing (4); the first bevel gear (9) and the third bevel gear (11) are installed on the gear shaft (10) through a first one-way clutch (16) and a second one-way clutch (21), and both are meshed with the second bevel gear (20) at the same time; the second bevel gear shaft (19) is connected to the DC generator (18) through the coupling (17).

6. The variable stiffness composite electric tractor vibration energy feedback device according to claim 4, characterized in that: The piezoelectric energy feeding module (B) comprises a protective plate (13), a shock absorbing spring (14), an upper cover plate (15), a long column (23), a fulcrum (24), a lower base plate (25), a lever (26), a short column (27), a piezoelectric matrix (28), a piezoelectric ceramic (29) and a buffer spring (30); the piezoelectric energy feeding module (B) is installed on the thirteenth connecting rod (47) and the fifteenth connecting rod (49) of the lower box body (4); the upper cover plate (15), the lower base plate (25) and the protective plate (13) are all rectangular parallelepiped steel plates, and the lower base plate (25) is connected to the protective plate (13); the bottom of the upper cover plate (15) is connected to the protective plate (13) through the shock absorbing spring (14), so that the upper cover plate (15) can be moved up and down. reciprocating vibration; the piezoelectric matrix (28) is installed between the long column (23) and the short column (27), and the piezoelectric ceramic (29) is arranged on the piezoelectric matrix (28); the fulcrum (24) is arranged at the bottom 1 / 3 groove of the lever (26), and the lever (26) can rotate up and down along the fulcrum (24); the bottom of the long column (23) is hinged to the lever (26) for triggering the lever (26) to rotate downward; the short column (27) is arranged on the lever (26) for driving the piezoelectric matrix (28) to rotate upward and compress the buffer spring (30); the bottom of the buffer spring (30) is arranged on the short column (27), and the top is connected to the bottom of the upper cover plate (15).

7. The variable stiffness composite electric tractor vibration energy feedback device according to claim 1, characterized in that: The annular ball bearing (3) comprises a guide rail (33), a ball bearing (34) and a base (35); the ball bearing (34) is installed in the guide rail (33) and rotates along the guide rail (33); the guide rail (33) is installed on the base (35); and the base (35) is installed on the upper box body (1).

8. The variable stiffness composite electric tractor vibration energy feedback device according to claim 1 or 7, characterized in that: The baffle (6) is arranged on the lower box body (4) and is connected to the annular ball (3), so that the annular ball (3) can roll up and down along the baffle (6).

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