Battery quick-changing device and electric tractor

Abstract

The utility model discloses a battery quick-changing device and an electric tractor equipped with the battery quick-changing device. The battery quick-changing device comprises a pull rod component, a lifting actuating device, a hanging structure, a swing connecting mechanism and a replaceable battery box, according to the electric tractor, all the components are specifically arranged, so that the battery of the electric tractor can be rapidly replaced, the weight of the whole tractor during operation is reduced, the pressure to the ground is reduced, soil is protected, the crop yield is improved, the battery rapid replacing device is integrated on the tractor, a battery replacing station does not need to be additionally arranged, fixed asset investment is reduced, and popularization is convenient.

Description

Technical Field

[0001] This utility model relates to the fields of agricultural machinery and engineering machinery, specifically to a battery quick-change device and an electric tractor equipped with the battery quick-change device. Background Technology

[0002] With continuous upgrades in battery technology, the emergence of new battery materials, and in-depth optimization of batteries, their costs continue to decline, driven by both economies of scale and technological innovation. Simultaneously, the deployment of new energy sources in rural areas is accelerating. Distributed photovoltaic and wind power systems, with their high efficiency, cleanliness, and renewable characteristics, are widely deployed throughout rural areas, forming a vast and stable distributed energy network that provides ample power support for the electrification of modern agriculture. Against this backdrop of multi-dimensional technological advancements, the basic conditions for tractor electrification are gradually being improved. Electric tractors, with their significant advantages of zero emissions, high efficiency, and low noise, have become an important direction for the future development of agricultural machinery. Their high-performance battery systems not only meet the demands of long-term, high-intensity operation but also enable rapid recharging through intelligent charging management systems, greatly improving operational efficiency. Furthermore, the intelligent control system of electric tractors can seamlessly integrate with rural distributed energy networks, achieving efficient energy management and optimized allocation, further reducing operating costs.

[0003] The electrification of tractors faces numerous challenges, one of the key obstacles being their complex and dispersed working areas. Tractors typically operate in vast and remote farmlands, which are often scattered and may even span multiple farms or regions. Many farming families' fields are not contiguous, requiring tractors to move frequently between different locations and potentially remaining out of service for days or weeks. This dispersion not only increases the difficulty of building charging infrastructure but also places higher demands on battery range.

[0004] Another pressing issue is the trade-off between tractor weight and battery range. To meet the demands of long-duration, high-intensity operations, electric tractors need large-capacity battery packs, significantly increasing their weight. Excessively heavy tractors can over-compact the soil, negatively impacting crop growth. Furthermore, while large-capacity batteries improve range, they also increase charging time and cost. For example, some electric tractors currently only offer a range of 1-3 hours, which is clearly insufficient for extended, large-area operations.

[0005] Therefore, how to control the weight of electric tractors to reduce soil compaction while ensuring their range has become an important issue in the development of electric tractor technology. Integrating a quick-swap battery device into the electric tractor would allow for rapid battery replacement during operation, reducing the capacity and weight of individual batteries and thus solving the aforementioned technical problems.

[0006] Chinese invention patent announcement CN118438921B discloses a power battery quick-swap device and vehicle. By detachably connecting the battery pack module and the frame module, it solves the problem of existing electric tractors not being able to swap batteries. However, battery swapping still requires the assistance of external facilities. For tractors that work alone in the field most of the time, its convenience greatly affects its promotion. Moreover, the stability and reliability of its setting method also need to be improved. Utility Model Content

[0007] The purpose of this invention is to provide a battery quick-change device and an electric tractor equipped with the battery quick-change device to solve the above-mentioned problems.

[0008] Specifically, this is achieved through the following technical solution:

[0009] A quick-change battery device includes a pull rod component, a lifting actuation device, a hanging structure, a swing connection mechanism, and a quick-change battery box.

[0010] The pull rod assembly includes at least three pull rods, and at least two of the pull rods serve as active pull rods. The active pull rods are fixed together and connected to the lifting actuation device.

[0011] One end of the active tie rod is connected to the mounting structure, and the other end is connected to the swing connection mechanism. The swing connection mechanism has a swing center of the active tie rod, and the swing connection mechanism is connected to the tractor chassis through the swing center of the active rod that allows the active tie rod to swing up and down.

[0012] A lifting rotation shaft is provided between the hanging structure and the swing center of the active pull rod. The distance between the center point of the hanging structure and the swing center of the active pull rod is greater than 1.5 times the distance between the swing center of the active pull rod and the lifting rotation shaft. (This limits the leverage ratio of the active pull rod during lifting.)

[0013] There must be at least one quick-change battery box, and at least three fixing pins must be provided on the quick-change battery box. At least two of these fixing pins must be located on the side of the quick-change battery box and be compatible with the mounting structure. A battery is installed inside the quick-change battery box.

[0014] The mounting structure limits the position of the fixing pin and allows the fixing pin to rotate within the mounting structure.

[0015] Lifting one end of the actuator (e.g.)Figure 1 The example in the middle shows the top end connected to the tractor chassis, and the other end (such as...) Figure 1 The example in the diagram shows the bottom end, which is connected to the active pull rod via a lifting rotating shaft. The lifting rotating shaft is located on the active pull rod between the hanging structure and the swing connection mechanism, and at the bottom end of the lifting actuation device (connecting both simultaneously, i.e., simultaneously located on both). The terms "top end" and "bottom end" are merely directional descriptions to match the diagram and do not define the absolute position.

[0016] The lifting actuation device includes one or more hydraulic cylinders, the total effective piston area of ​​the hydraulic cylinders is s, which satisfies...

[0017] s>(15-5×cos(p×0.01134)) 2 ;

[0018] Where: p is the sum of the rated power of all drive motors of the tractor, in kW; s is in mm. 2 The cosine function is calculated in radians.

[0019] When the pressure in the tractor's pressure system is essentially constant, this invention, through multiple experiments, discovered that the sum of the effective piston areas of the hydraulic cylinders and the sum of the rated power of all drive motors of the tractor exhibit a cosine relationship plus an offset. Further numerical simulations were used to obtain the curve, and this relationship was then corrected through further experiments to arrive at the aforementioned formula. This formula is used to limit the minimum lifting force of the lifting actuator. This relationship between the sum of the effective piston areas and the rated power enables the lifting actuator to lift the weight of the battery that meets the required operating time and power.

[0020] Preferably, the lifting actuator includes a motor and a screw. The sum of the rated power of all motors of the lifting actuator on the electric tractor is p2, which satisfies: p2>200-50×cos(p×0.01134); where: p is the sum of the rated power of all drive motors of the tractor in kW, p2 is in W, and the cosine function is calculated in radians.

[0021] This invention, through multiple experiments, discovered that the sum of the rated power of all motors in the lifting actuators is cosine-biased to the sum of the rated power of all drive motors in the tractor, plus an offset. Further numerical simulations were used to obtain the curve, and this relationship was then corrected through further experiments to arrive at the aforementioned formula. This formula limits the minimum electrical power of the lifting actuator, ensuring it can lift the weight of the battery required for the specified operating time and power. The operating time and power of the tractor are non-linearly related to its total power; lower-power tractors handle more types of tasks and have longer downtime, thus requiring lower average and maximum power. Therefore, the relationship between battery capacity and power can be approximated by a trigonometric function curve in a single quadrant. This invention combines this trigonometric function curve with experimental experience to obtain the aforementioned formula. Satisfying this formula satisfies the minimum power requirement for the lifting actuator to lift the battery weight required for the specified operating time and power.

[0022] Preferably, when the electric tractor travels in a straight line, the axis of rotation of the tires or tracks is the y-axis of the tractor; the perpendicular line from the ground (as a plane) is the z-axis of the tractor; and the direction perpendicular to both the y and z axes is the x-axis of the tractor, which is the tractor's direction of travel. The swing axis of the active linkage is the yc-axis, the rotation axis of the fixed pin is the ya-axis, and the rotation axis of the lifting shaft is the yb-axis. The projections of the ya-axis, yb-axis, and yc-axis onto the xz-plane are points a, b, and c, respectively. The distances between the points projected onto the line connecting points a and b are Lab, Lbc, and Lac, respectively, satisfying the requirement that Lac / Lab > 1.5. This relationship is used to limit the lever ratio of the active linkage during lifting, thus ensuring the working range of the lifting action while preventing excessive power demand on the lifting actuator, thereby ensuring the reliability of the lifting action under specific power requirements.

[0023] Preferably, a spring assembly is provided between the lifting rotating shaft and the active tie rod and the fixing point of the tractor chassis. The spring assembly consists of one or more disc springs. The total stiffness coefficient of the spring assembly is K, which satisfies: 0.6p>K>0.06p; where p is the sum of the rated power of all drive motors of the tractor in kW, and the unit of the total stiffness coefficient K is kN / mm.

[0024] This formula is used to limit the selection of springs suitable for the application scenarios of this utility model, so as not to be too soft or too hard. This ensures that the vibration of the battery pack, which meets the working time and power requirements of the tractor, can be effectively filtered and isolated by the spring system during tractor operation and travel. The battery and its suspension system will not be subjected to too much energy intensity and amplitude vibration load, thereby extending the system life and ensuring reliability.

[0025] Preferably, the hydraulic cylinder includes a hydraulic valve for controlling the oil inlet and outlet of the hydraulic cylinder, and the hydraulic valve includes a rod-shaped valve core.

[0026] The valve core includes a cylindrical surface with a diameter larger than other parts of the valve core. Two or more vibration damping openings are provided on the outer circle of the end face of this cylindrical surface. The cross-sectional area of ​​each vibration damping opening is the area projected onto a plane perpendicular to the valve core axis by the shape enclosed by the vibration damping opening and the outer circle of the cylindrical surface. The cross-sectional area of ​​the vibration damping opening changes monotonically along the axial direction. The sum of the cross-sectional areas at the maximum cross-sectional area of ​​all vibration damping openings is s², satisfying: Where: p is the sum of the rated power of all drive motors of the tractor, in kW; s2 is in mm. 2 .

[0027] This invention reveals that by considering hydraulic and mechanical systems as mass-spring-damper systems, and assuming the system input is an external force F(t) and the output is the mass displacement x(t), the system's equation of motion can be expressed as:

[0028] M×x''(t) + c × x'(t) + k × x(t) = F(t)

[0029] Where x''(t) is the second derivative of displacement, representing acceleration; and x'(t) is the first derivative of displacement, representing velocity.

[0030] Taking the Laplace transform of this equation of motion, we can obtain the system's transfer function G(s):

[0031] G(s) = X(s) / F(s) = 1 / (m × s 2 + c × s + k)

[0032] Where s is a complex frequency domain variable, and X(s) and F(s) are the Laplace transforms of displacement x(t) and external force F(t), respectively.

[0033] By analyzing this transfer function, key dynamic characteristics such as system stability, frequency response, and damping characteristics can be analyzed. Combined with numerous experiments, it was determined that the sum of the cross-sectional area of ​​the damping port and the rated power, as well as the product of the ratio of Lab to Lac, have a synergistic effect. Through mathematical fitting, the above empirical formula was derived. This formula is used to limit the damping performance of the vibration damping system of this invention in the application scenario of this invention. This ensures that the vibration (i.e., the aforementioned displacement) of the battery pack (i.e., the mass mentioned above) that meets the tractor's operating time and power requirements can be effectively filtered and isolated by the hydraulic system. The battery and its suspension system will not be subjected to excessive energy intensity and amplitude vibration loads, thereby extending system life and ensuring reliability.

[0034] Preferably, the hydraulic cylinder is supplied with hydraulic oil with pressure and flow rate by a hydraulic pump. The hydraulic oil flows in or out through a hydraulic valve. A hydraulic accumulator (or hydraulic energy storage device) is connected in parallel or in series in the inflow or outflow channel from the hydraulic valve to the hydraulic cylinder. The nominal volume of the hydraulic accumulator is [missing information]. ,satisfy: Where: p is the sum of the rated power of all drive motors of the tractor, in kW; The unit is liter (L).

[0035] This invention reveals that by considering hydraulic and mechanical systems as mass-spring-damper systems, and assuming the system input is an external force F(t) and the output is the mass displacement x(t), the system's equation of motion can be expressed as:

[0036] M×x''(t) + c × x'(t) + k × x(t) = F(t);

[0037] Where x''(t) is the second derivative of displacement, representing acceleration; and x'(t) is the first derivative of displacement, representing velocity.

[0038] Taking the Laplace transform of this equation of motion, we can obtain the system's transfer function G(s):

[0039] G(s) = X(s) / F(s) = 1 / (m × s2 + c × s + k);

[0040] Where s is a complex frequency domain variable, and X(s) and F(s) are the Laplace transforms of displacement x(t) and external force F(t), respectively.

[0041] By analyzing this transfer function, key dynamic characteristics such as system stability, frequency response, and damping characteristics can be analyzed. Combined with numerous experiments, it was determined that the sum of the nominal volume and rated power of the hydraulic accumulator, as well as the product of the ratio of Lac to Lbc, have a synergistic effect. Through mathematical fitting and multiple experiments, the above empirical formula was derived. This formula is used to further optimize the system's buffering performance, ensuring that the vibrations of the battery pack, which meets the tractor's operating time and power requirements, can be effectively filtered and isolated by the hydraulic system during tractor operation and travel. The battery and its suspension system will not be subjected to excessive energy intensity and amplitude vibration loads, thereby extending system life and ensuring reliability.

[0042] Preferably, at least one active tie rod is also provided with a side tie rod between it and the tractor chassis. One end of the side tie rod is fixed to the active tie rod at point d; the other end is fixed to the tractor chassis at point e; the straight-line distance between d and e is Lde, which satisfies the requirement that Lde / Lac>1.05.

[0043] To limit the leverage ratio of the active lever, which is used to reduce horizontal instability, the formula is used to limit the length and the angle formed by the side lever and the active lever. This ensures that the active lever has lateral freedom, effectively reduces horizontal instability, and thus ensures the fault tolerance when attaching the battery. It also ensures that the overall size of the system is not too large, increases the system life, and improves the system reliability.

[0044] Preferably, the pull rod assembly includes two active pull rods and one upper pull rod, with the two active pull rods located on both sides and the upper pull rod located at the top.

[0045] Preferably, the quick-change battery box is provided with at least 3 fixing pins, of which at least 2 fixing pins are battery-side fixing pins. The battery-side fixing pins are located on the side of the quick-change battery box and can be matched with the hanging structure (preferably, there are two sets of hanging structures, which are respectively connected to the two active pull rods located on both sides). At least 1 fixing pin is provided on the top of the quick-change battery box, which is used to hinge with the upper pull rod through the upper support shaft of the battery.

[0046] Preferably, the hydraulic cylinder includes a right lifting cylinder and a left lifting cylinder (which respectively cooperate with two active tie rods located on both sides). Both the right and left lifting cylinders are provided with an upper cylinder pin at the top and a lower cylinder pin at the bottom. The lower cylinder pin is hinged to the lifting rotation shaft, and the upper cylinder pin is rotatably connected to the upper part of the swing connection mechanism.

[0047] Preferably, the swing connection mechanism is a front lifting bracket (i.e., a lifting bracket set at the front end of the tractor).

[0048] Preferably, the hook-shaped connection structure is a hook-shaped connection structure respectively provided at the end of the active pull rod, the hook-shaped connection structure surrounding the battery side fixing pin from the bottom and side in a hook-shaped form.

[0049] An electric tractor, wherein the electric tractor is equipped with the aforementioned battery quick-change device.

[0050] Preferably, in addition to the quick-change battery, the electric tractor also has one or more batteries fixedly installed, with a nominal total capacity of Cb, satisfying Cb > 0.01p; where Cb is in kilowatt-hours (kW·h). This formula is used to limit the nominal total capacity of the fixedly installed batteries. This limitation in the present invention ensures that the tractor's movement and the hydraulic system can complete the necessary work to meet the battery connection time during quick-change battery connection.

[0051] The electric tractor is equipped with at least two grounding devices to achieve contact between the electric tractor and the ground. When the tractor is traveling in a straight line, the axis of rotation of the grounding device is defined as the y-axis of the tractor. The perpendicular line from the ground to the ground is defined as the z-axis of the tractor. The direction perpendicular to both the y-axis and z-axis is defined as the x-axis of the tractor, which is the main direction of travel of the tractor. The plane formed by the x-axis and y-axis is defined as the xy plane. The plane formed by the y-axis and z-axis is defined as the yz plane. The plane formed by the x-axis and z-axis is defined as the xz plane.

[0052] The electric tractor is equipped with at least one drive motor, which is connected to the walking grounding device through a walking transmission shaft or a walking speed change device and transmits power to the walking grounding device.

[0053] The sum of the rated power of all drive motors is p, where the rated power is the maximum power that can be continuously delivered for at least 60 seconds under normal operating conditions.

[0054] The travel transmission has two or more gear ratios or is equipped with a continuously variable transmission (CVT); the minimum and maximum values ​​of the at least two gear ratios are Imin and Imax, respectively, or the minimum and maximum reduction ratios of the CVT are Imin and Imax, respectively, where Imin and Imax satisfy Imax / Imin>1.4; this formula is used to limit the speed ratio span between two or more gears in a gearbox or a CVT, so that the gear ratio setting of the gearbox can meet the complex working conditions of the tractor, including a large speed range and torque range requirements.

[0055] The electric tractor is equipped with at least one PTO motor, which is connected to a PTO gearbox. The rated power of the PTO motor is p5, satisfying p5 > 0.4p; this formula is used to limit the rated power of the PTO motor so that the power output of the tractor, as well as the pressure and flow of the hydraulic system, can meet the complex working conditions of the tractor. The PTO reducer has at least two gear positions and is equipped with at least one clutch.

[0056] The beneficial technical effects of this utility model are as follows:

[0057] 1. This utility model, by incorporating a replaceable battery box on the tractor and integrating a quick-change battery device, allows for rapid and convenient battery replacement during operation, significantly improving the tractor's actual range and consequently its operational efficiency. Furthermore, the quick-change device allows for the carrying of a lighter battery during operation. When the battery is depleted, a fully charged battery can be quickly replaced, reducing the overall weight of the tractor, decreasing ground pressure, protecting the soil, and increasing crop yield. Since the quick-change device is integrated into the tractor, there is no need for a separate battery swapping station, reducing fixed asset investment and facilitating widespread adoption. This utility model, by specifically setting the leverage ratio of the active lever during lifting, ensures the working range of the lifting action while keeping the power of the lifting actuation device within a reasonable range. This also enables a shorter battery swapping process, facilitates battery swapping for tractors operating independently in the field, and supports unmanned battery swapping, meeting the requirements of agricultural automation and operational efficiency.

[0058] 2. This utility model provides an embodiment that uses a hydraulic cylinder as a battery lifting device. When the tractor has high power, the high-power-density hydraulic system can ensure the system size and weight. By setting a minimum total area of ​​the hydraulic cylinder, the lifting actuation device can lift the weight of the battery to meet the working time and power requirements. By setting vibration damping ports on the hydraulic valve core of the hydraulic cylinder and by specifically setting the relationship between the hydraulic cylinder piston and the vibration damping ports, the buffer system is not too stiff. This allows the vibration of the battery pack, which meets the working time and power requirements of the tractor, to be effectively filtered and isolated by the hydraulic system during tractor operation and travel. The battery and its suspension system are not subjected to excessive energy intensity and amplitude vibration loads, thus extending system life and ensuring reliability. By setting a hydraulic accumulator in the hydraulic circuit and specifically setting the nominal volume of the hydraulic accumulator, the hydraulic accumulator, as a buffer, is not too stiff. This allows the vibration of the battery pack, which meets the working time and power requirements of the tractor, to be effectively filtered and isolated by the hydraulic system during tractor operation and travel. The battery and its suspension system are not subjected to excessive energy intensity and amplitude vibration loads, thus effectively reducing battery vibration during field operations, increasing system life, and improving system reliability.

[0059] 3. Another embodiment of this utility model uses an electric pull rod as the battery lifting device, avoiding a complex hydraulic system. This is especially beneficial for low-power tractors, where the battery system weight is relatively low, thus reducing costs and improving reliability. By setting the rated power of the electric pull rod motor in relation to the rated power of the tractor, the minimum electric power of the lifting actuator is ensured to meet the requirement that the lifting actuator can lift the weight of the battery that balances the working time, working power, charging time, and working time. Furthermore, by setting a spring assembly between the lifting shaft and the drive pull rod, and coordinating the relationship between the total stiffness coefficient of the spring assembly and the rated power of the tractor, the vibration of the battery pack that meets the working time and working power requirements of the tractor during tractor operation and travel can be effectively filtered and isolated by the spring system. The battery and its suspension system will not be subjected to excessive energy intensity and amplitude vibration loads, increasing system life and improving system reliability.

[0060] 4. This utility model simultaneously ensures the lateral freedom of the active tie rod by setting a side tie rod between the active tie rod and the tractor chassis, and by limiting the relationship between their positions. This ensures the fault tolerance rate when attaching the battery, while also preventing the overall size of the system from becoming too large. This effectively reduces horizontal instability, thereby increasing system lifespan and improving system reliability. Furthermore, by setting a fixed battery on the electric tractor and specifically setting the relationship between its capacity and the tractor's rated power, the necessary movement of the tractor and the normal operation of the battery swapping device by the hydraulic system are ensured during the battery swapping process. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the integrated battery quick-swap device according to one embodiment of the present invention.

[0062] Figure 2 This is a schematic diagram of the overall structure of an electric tractor according to one embodiment of the present invention.

[0063] Figure 3 This is a top view and a partial cross-sectional view of the powertrain of an electric tractor according to one embodiment of the present invention.

[0064] Figure 4 This is a schematic diagram of the overall structure of an electric tractor powertrain and battery quick-change device according to one embodiment of the present invention.

[0065] Figure 5 This is a schematic diagram of an electric tractor, representing another embodiment of the present invention.

[0066] Figure 6 This is a schematic diagram of a hydraulic valve core according to one embodiment of the present invention.

[0067] The components include: 1. Front wheel; 2. Upper tie rod; 3. Battery upper support shaft; 4. Quick-change battery box; 5. Right lifting cylinder; 6. Left lifting cylinder; 7. Battery side fixing pin; 8. Active tie rod; 8-1. Hook-shaped connecting structure; 8-2. Side tie rod; 9. Lower cylinder pin; 10. Upper cylinder pin; 11. Front lifting bracket; 12. Lower lifting arm pivot; 13. Tractor chassis; 14. Front axle; 15. Battery quick-change device; 16. Fixed battery; 17. Frame; 18. Battery temperature... 19. Oil pump transfer case; 20. Oil pump; 21. Left travel gearbox; 22. Left travel motor; 23. Left track; 24. PTO drive shaft and universal joint; 25. PTO motor; 26. PTO gearbox; 27. PTO clutch; 28. Right travel motor; 29-1. Friction pads of the brake device; 29-2. Actuator of the brake device; 30. Right travel gearbox; 31. Right track; 32. Hydraulic valve core; 32-1. Vibration damping port; Ya. Rotation axis of the fixed pin; Yb. Rotation axis of the lifting shaft; Yc. Swing axis of the active tie rod; X. Main travel direction of the tractor; Y. Rotation axis direction of the main rotational motion of the travel grounding device when the tractor is traveling in a straight line; Z. Perpendicular direction when the ground is a plane. Detailed Implementation

[0068] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present invention.

[0069] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate for the embodiments of this application described herein.

[0070] In this application, when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. In this specification and claims, terms such as "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "side," "top," "bottom," "far," and "near," indicating orientation or positional relationships, are based on the orientation shown in the drawings or actual usage positional relationships. They are merely relational terms determined for the convenience of describing the structural relationships of the components or elements of this disclosure and do not specifically refer to any component or element in this disclosure. They should not be construed as limitations on this disclosure, nor as limitations on positional and orientational relationships during transportation and other uses. In this specification and claims, terms such as "fixed," "connected," "linked," "equipped with," "enclosed," and "configured," should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this disclosure can be determined according to the specific circumstances and should not be construed as limitations on this disclosure.

[0071] Example 1

[0072] This embodiment provides how to... Figure 1 The battery quick-change device shown is equipped with, for example, Figure 5 The technical solution shown on the electric tractor (will) Figure 1 The front wheel and front axle were removed and replaced with tracks, and two sets of tracks were installed on the left and right sides to enable the electric tractor to make contact with the ground. Figure 1 and Figure 3 As shown, two drive motors are arranged on the left and right sides, respectively. Each drive motor is connected to the left and right tracks via a travel transmission device and transmits power to the tracks. The rated power of each drive motor is 100kW, and the total power of the two drive motors is 200kW. The travel transmission device has two gear ratios, with the minimum and maximum values ​​being Imin and Imax, respectively. Imin = 12, Imax = 30, satisfying Imax / Imin > 1.4. The tractor is equipped with a battery quick-change device, including three linkages. Two of the active linkages are connected to two hydraulic cylinders via rotatable cylinder lower pins, with the rotation center defined as the yb axis. The end of the active linkage has a hook-like hook structure to ensure that the object being hooked is restricted from moving in the x-axis direction after normal hooking. The other end is connected to the tractor chassis via a sleeve hinge, and the swing axis of the active linkage is defined as the yc axis. The other ends of the two hydraulic cylinders are connected to the tractor chassis via cylinder upper pins. The effective diameter of the pistons in each of the two hydraulic cylinders is 30 mm, meaning the total effective piston area of ​​the hydraulic cylinders is 1400 mm². 2 It is greater than (15-5×cos(p×0.01134)).2 =330mm 2 .

[0073] Within the scope of this utility model, at least one set of springs can be installed as a buffer at any link in the force transmission chain from the lifting actuation device (force application point) to the quick-change battery box (mass). In this embodiment, the lifting actuation hydraulic cylinder at the upper pin 10 of the cylinder is connected to the tractor chassis through a set of springs. One end of the spring abuts against the lifting actuation hydraulic cylinder, and the other end abuts against the tractor chassis. The spring acts directly between the lifting actuation hydraulic cylinder and the tractor chassis. The spring stiffness coefficient K = 20kN / mm, satisfying 0.6p > K > 0.06p.

[0074] The electric tractor includes a quick-change battery box with three fixing pins, two on the sides and one on the top. The two side fixing pins are cylindrical. The hook-connecting structure consists of hook-shaped connecting structures located at the ends of the active pull rod. The hook-shaped connecting structures surround the battery-side fixing pins from the bottom and sides in a hook-like form. The hook-shaped connecting structures can rotate after being engaged, and their rotation center is defined as the ya axis.

[0075] The projections of the y-axis, y-b axis, and y-c axis onto the xz plane are points a, b, and c, respectively. The distances between the points projected onto the line connecting points a and b are Lab, Lbc, and Lac, respectively. Lbc is 240 mm, Lac is 800 mm, and Lab is 560 mm.

[0076] The oil inlet and outlet of the hydraulic cylinder are controlled by a hydraulic valve; the hydraulic valve includes a rod-shaped valve core; such as Figure 6 As shown, the valve core includes a cylindrical surface, and three damping ports are provided on the outer circle of the cylindrical surface's end face. The cross-sectional area of ​​each damping port is the area projected onto a plane perpendicular to the valve core axis at different positions, representing the shape enclosed by the damping port and the outer circle of the cylindrical surface. The cross-sectional area of ​​the damping port changes monotonically along the axial direction. The maximum sum of the cross-sectional areas of all damping ports is located on the end face of the cylindrical surface and is 15 mm. 2 greater than .

[0077] A spring-type hydraulic accumulator is connected in parallel or in series in the inflow or outflow channel from the hydraulic valve to the hydraulic cylinder. The nominal volume of the hydraulic accumulator is 0.4 liters, greater than... .

[0078] like Figure 4As shown, a side tie rod is also provided between the active tie rod and the tractor chassis. One end of the side tie rod is fixed to the active tie rod at point d; the other end is fixed to the tractor chassis at point e; Lde is the straight-line distance between de, which is 900mm, and Lde / Lac=1.125>1.05.

[0079] When the electric tractor is running normally, it is also equipped with a battery with a nominal capacity of 6 kWh > 0.01p = 2 kWh.

[0080] like Figure 3 and Figure 4 As shown, the electric tractor is equipped with one PTO motor, which is connected to a PTO transmission. The PTO transmission has two gears to achieve different output speeds and includes a neutral gear. The PTO reducer is equipped with a clutch to disconnect the power connection between the PTO motor and the PTO shaft when not needed. The rated power of the PTO motor is 150kW, which meets the requirement of p5>0.4p. The PTO motor is connected to the PTO shaft to provide output power to the attached implements. The PTO motor is also connected to a hydraulic pump to provide hydraulic oil to the entire tractor. If the rated power of the PTO motor does not meet the requirements, it will not be able to provide sufficient PTO output power, while also providing sufficient hydraulic power to the entire vehicle.

[0081] In other embodiments, it can be configured as follows: Figure 1 and Figure 2 As shown, the front and rear wheels are set as the driving components, and other settings can be the same as in this embodiment.

[0082] The working process of this embodiment is as follows: When it is necessary to quickly unlock and release the battery of the electric tractor, first extend the hydraulic cylinder, lower the active pull rod, and disengage its hook-shaped connection from the fixing pin of the battery box. Then, loosen the top fixing pin and its connecting pull rod, and reverse the tractor to completely detach the battery box from the tractor. The operation process for attaching the battery box is the reverse of this.

[0083] Comparative Example 1

[0084] The other settings in this comparative example are the same as in Example 1, except that the effective diameter of the pistons of the two hydraulic cylinders is 10 mm, that is, the total effective area of ​​the pistons of the hydraulic cylinders is 160 mm. 2 It is less than (15-5×cos(p×0.01134)). 2 =330mm 2The requirement is that the effective piston area of ​​the comparative example is much smaller than the range set by this utility model. Since the tractor requires the battery weight to meet the working needs of at least one hour, the battery weight to meet this requirement is 700 kg. The effective piston area of ​​the hydraulic cylinder set in this comparison example is completely unable to lift the battery of this weight through testing, resulting in replacement failure.

[0085] Comparative Example 2

[0086] The other settings of this comparative example are the same as those of Example 1. The difference is that when the electric tractor is running normally, it is also equipped with a battery with a nominal capacity of 1 kWh. Since 200 kW × 0.01 = 2 kWh, the nominal total capacity of the fixedly installed battery in this comparative example is less than the minimum value set by this utility model. After equipping this comparative example and implementing battery quick-change, it was found that after disconnecting the quick-change battery, the 1 kWh battery of this comparative example can maintain the hydraulic system and power required for the tractor to change the battery for about 1 minute. However, the battery quick-change device of this utility model in Example 1 takes 2.5 minutes to change the battery, so the power is cut off during the change process and the battery change function cannot be reliably completed.

[0087] Comparative Example 3

[0088] The other settings in this comparative example are the same as in Example 1, except that the maximum sum of the cross-sectional areas of all vibration damping ports is located on the end face of the cylindrical surface, which is 1 mm. 2 Not satisfied with greater than The requirements were found that during field work, due to severe vibrations, the fixing pins broke off from the battery box prematurely.

[0089] Comparative Example 4

[0090] The other settings in this comparative example are the same as in Example 1, except that the nominal volume of the hydraulic accumulator is 0.1 liters, which does not meet the requirement of being greater than... The requirements were found that the active tie rod broke prematurely due to severe vibrations during field work.

[0091] Example 2

[0092] This embodiment provides an implementation method where the lifting actuation device is an electric pull rod (for electric tractors with a power of less than 100kW). Specifically, the total rated power of the drive motor is 50kW. The hydraulic cylinder of the lifting actuation device consists of a motor and a screw. The sum of the rated power of all motors of the lifting actuation devices on the electric tractor, p2, is 500W, which meets the requirement of p2>200-50×cos(p×0.01134).

[0093] Comparative Example 5

[0094] The other settings in this comparative example are the same as in Example 2, except that the sum of the rated power of the motors of the electric levers of the lifting actuation device is less than 200-50×cos(p×0.01134), specifically 100W. Since the tractor requires the battery weight to meet at least one hour of working needs, the battery weight to meet this requirement is 700 kg. Through testing, it was found that the motors with the rated power set in this comparative example could not lift the battery of this weight within the normal battery replacement time, thus causing the battery replacement to fail.

[0095] Comparative Example 6

[0096] The other settings in this comparative example are the same as in Example 2. The difference is that the total stiffness coefficient K of the spring assembly is 5kN / mm, which does not meet the requirement of 0.6p>K>0.06p. It was found that the active tie rod broke prematurely due to severe vibration when working in the field.

[0097] The detailed descriptions listed above are merely specific descriptions of feasible implementations of this utility model, and are not intended to limit the scope of protection of this utility model. All equivalent implementations or modifications made without departing from the spirit of this utility model should be included within the scope of protection of this utility model.

[0098] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it may be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

Claims

1. A battery quick-change device, characterized in that, Includes a pull rod assembly, a lifting actuation device, a mounting structure, a swing connection mechanism, and a quick-change battery box; The pull rod assembly includes at least three pull rods, and at least one of the pull rods serves as the active pull rod, which is connected to the lifting actuation device. One end of the active tie rod is connected to the mounting structure, and the other end is connected to the swing connection mechanism. The swing connection mechanism has a swing center of the active tie rod, and the swing connection mechanism is connected to the tractor chassis through the swing center of the active tie rod that allows the active tie rod to swing up and down. A lifting rotation shaft is provided between the hanging structure and the swing center of the active tie rod. The distance between the center point of the hanging structure and the swing center of the active tie rod is greater than 1.5 times the distance between the swing center of the active tie rod and the lifting rotation shaft. At least one quick-change battery box is provided, and at least three fixing pins are provided on the quick-change battery box, of which at least two fixing pins are provided on the side of the quick-change battery box and can be matched with the hanging structure; The mounting structure defines the position of at least two fixing pins and allows the fixing pins to rotate within the mounting structure. The top of the lifting actuator is connected to the tractor chassis, and the bottom is connected to the drive rod through a lifting rotating shaft. The lifting rotating shaft passes through the drive rod, which is located between the hook structure and the swing connection mechanism, and the bottom of the lifting actuator. The lifting actuation device includes at least one hydraulic cylinder, and the total effective piston area of ​​the hydraulic cylinder is s, which satisfies s>(15-5×cos(p×0.01134)). 2 ; Where: p is the sum of the rated power of all drive motors of the tractor, in kW; s is in mm. 2 The cosine function is calculated in radians.

2. The battery quick-change device according to claim 1, characterized in that, The hydraulic cylinder of the lifting actuation device is replaced by a motor and a screw. The sum of the rated power of all motors of the lifting actuation device on the electric tractor is p2, which satisfies: p2>200-50×cos(p×0.01134); Where: p is the sum of the rated power of all drive motors of the tractor, in kW; p2 is in W; and the cosine function is calculated in radians.

3. The battery quick-change device according to claim 1 or 2, characterized in that, A spring assembly is provided between the lifting rotating shaft and the active tie rod and the fixing point of the tractor chassis. The total stiffness coefficient of the spring assembly is K, which satisfies: 0.6p > K > 0.06p; Where: p is the sum of the rated power of all drive motors of the tractor, in kW, and the total stiffness coefficient K is in kN / mm.

4. The battery quick-change device according to claim 1 or 2, characterized in that, When the electric tractor travels in a straight line, the axis of rotation of the tires or tracks is the y-axis of the tractor; the perpendicular line from the ground to the plane is the z-axis of the tractor; the direction perpendicular to both the y-axis and z-axis is the x-axis of the tractor, which is the direction of travel of the tractor; the swing axis of the active linkage is the yc-axis, the rotation axis of the fixed pin is the ya-axis, and the rotation axis of the lifting shaft is the yb-axis; the projections of the ya-axis, yb-axis, and yc-axis onto the xz-plane are points a, b, and c, respectively; the distances between the points projected onto the line connecting points a and b are Lab, Lbc, and Lac, respectively. It meets the requirement that Lac / Lab > 1.

5.

5. The battery quick-change device according to claim 4, characterized in that, The hydraulic cylinder includes a hydraulic valve, which is used to control the oil inlet and outlet of the hydraulic cylinder. The hydraulic valve includes a rod-shaped valve core. The valve core includes a cylindrical surface with a diameter larger than other parts of the valve core. Two or more vibration damping openings are provided on the outer circumference of the end face of this cylindrical surface. The cross-sectional area of ​​each vibration damping opening is the area projected onto a plane perpendicular to the valve core axis by the shape enclosed by the vibration damping opening and the outer circumference of the cylindrical surface. The cross-sectional area of ​​the vibration damping opening changes monotonically along the axial direction. The sum of the areas of all vibration damping openings at their maximum cross-sectional areas is s², satisfying: ; Where: p is the sum of the rated power of all drive motors of the tractor, in kW; s2 is in mm. 2 .

6. The battery quick-change device according to claim 5, characterized in that, The hydraulic cylinder is supplied with pressurized and flowing hydraulic oil by a hydraulic pump. The hydraulic oil flows in or out through a hydraulic valve. A hydraulic accumulator is connected in parallel or in series in the inflow or outflow channel from the hydraulic valve to the hydraulic cylinder. The nominal volume of the hydraulic accumulator is [missing information]. ,satisfy: ; Where: p is the sum of the rated power of all drive motors of the tractor, in kW; The unit is liter (L).

7. The battery quick-change device according to claim 4, characterized in that, At least one active tie rod is connected to the tractor chassis by a side tie rod. One end of the side tie rod is fixed to the active tie rod at point d; the other end is fixed to the tractor chassis at point e; Lde is the straight-line distance between de and Lac, and Lde / Lac > 1.

05.

8. An electric tractor, characterized in that, The electric tractor is equipped with at least one battery quick-change device as described in any one of claims 1-7; The electric tractor is also fixedly equipped with one or more batteries, the nominal total capacity of which is Cb, satisfying: Cb>0.01p; The unit of Cb is kilowatt-hour (kW·h).

9. The electric tractor according to claim 8, characterized in that, The electric tractor is equipped with at least two grounding devices to achieve contact between the electric tractor and the ground. When the tractor is traveling in a straight line, the axis of rotation of the grounding device is defined as the tractor's y-axis. The perpendicular line from the ground to the ground is defined as the tractor's z-axis. The direction perpendicular to both the y-axis and z-axis is defined as the tractor's x-axis, which is the tractor's main direction of travel. The plane formed by the x-axis and y-axis is defined as the xy-plane. The plane formed by the y-axis and z-axis is defined as the yz-plane. The plane formed by the x-axis and z-axis is defined as the xz-plane. The electric tractor is also equipped with at least one drive motor, which is connected to the walking grounding device through a walking speed change device and transmits power to the walking grounding device. The sum of the rated power of all drive motors is p, where the rated power is the maximum power that can be continuously delivered for at least 60 seconds under normal operating conditions. The travel transmission device has at least two gear ratios, or is equipped with a continuously variable transmission (CVT); the minimum and maximum values ​​of the at least two gear ratios are Imin and Imax, respectively, or the minimum and maximum reduction ratios of the CVT are Imin and Imax, respectively, and Imin and Imax satisfy: Imax / Imin > 1.

4.

10. The electric tractor according to claim 8, characterized in that, The electric tractor is equipped with at least one PTO motor, which is connected to a PTO transmission; the rated power of the PTO motor is p5, satisfying the following: p5 > 0.4p; Where p is the sum of the rated power of all drive motors of the electric tractor.

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