A chassis for a submersible fork lift truck

Abstract

The utility model discloses a kind of frame chassis of latent fork truck, it is related to transport fork truck equipment technical field, including frame, the frame is closely provided with floating drive wheel assembly, floating driven wheel assembly and several fork containing groove, the floating drive wheel assembly is symmetrically parallel and is differential drive structure, the floating drive wheel assembly is hinged to the frame by fulcrum shaft on it, the both ends of the fulcrum shaft are respectively provided with driving driven wheel and driving driving wheel that are elastically arranged up and down, the floating driven wheel assembly wheel frame hinged shaft is hinged to the frame, the fork containing groove is equipped with fork guide block and fork buffer block. The utility model is to provide a kind of frame chassis of latent fork truck, structure is more compact, more strong, drive is more flexible, power response is more rapid and run is more silent.

Description

Technical Field

[0001] This utility model relates to the field of transport forklift equipment technology, specifically to a chassis of a stealth forklift. Background Technology

[0002] In automated logistics and warehousing systems, AGV (Automated Guided Vehicle) forklifts are widely used due to their flexibility and high space utilization. However, the chassis design of traditional AGVs often has some inherent defects: their chassis structure is often complex and bulky, resulting in a large overall space occupation, limited flexibility, and stability that needs improvement during high-speed operation or load changes; in terms of drive methods, common single-wheel drive or non-optimized differential structures lead to a large turning radius, insufficient path tracking accuracy, and poor maneuverability; in terms of power response, the lack of an effective power assistance mechanism results in mediocre performance during acceleration and emergency braking, affecting overall operational efficiency; in addition, the fork extension mechanism often generates significant collision noise between metal parts during operation, especially at the moment of extension or start-up, which not only affects the working environment but may also lead to structural fatigue or decreased precision with long-term use. These shortcomings limit the application potential of AGVs in scenarios with higher efficiency and more stringent environmental requirements. Therefore, there is an urgent need for a AGV chassis technology solution that is more compact, more stable, more flexible in drive, has a faster power response, and operates more quietly. Utility Model Content

[0003] Technical problem to be solved by the utility model

[0004] The technical problem to be solved by this utility model is to provide a chassis for a stealthy forklift with a more compact structure, stronger stability, more flexible drive, faster power response and quieter operation.

[0005] Technical solution

[0006] To solve the above problems, the technical solution provided by this utility model is as follows:

[0007] A chassis for a lurking forklift includes a frame. A floating drive wheel assembly, a floating driven wheel assembly, and several fork receiving slots are tightly disposed within the frame. The floating drive wheel assemblies are symmetrically and parallelly arranged and have a differential drive structure. Each floating drive wheel assembly is hinged to the frame via a pivot shaft. A driven wheel and a driving wheel, elastically arranged vertically, are respectively disposed at both ends of the pivot shaft. The wheel frame of the floating driven wheel assembly is hinged to the frame via a hinge shaft. A fork guide block and a fork buffer block are disposed within the fork receiving slots.

[0008] The frame, as the main skeleton, integrates all key components in a compact design, forming the basis for overall miniaturization and high rigidity. The floating drive wheel assembly adopts a dual-wheel differential drive structure, which not only significantly improves the vehicle's turning flexibility and path tracking accuracy through the differential principle, but its unique floating design (hinged to the frame via a pivot shaft) combined with the drive active wheel and drive driven wheel (i.e., spring supercharging device) elastically set at both ends of the pivot shaft provides powerful driving force while effectively absorbing ground impacts. During acceleration and deceleration, it utilizes the energy storage / release characteristics of the springs to greatly enhance the adhesion between the tires and the ground, thereby significantly enhancing acceleration, braking performance, and dynamic stability. The floating driven wheel assembly (hinged to the frame via a wheel frame hinge shaft) also adopts a floating connection, working in conjunction with the drive wheels to adapt to ground undulations and share the load, further ensuring the smooth operation of the entire vehicle. The fork guide blocks set in the fork housing slot precisely guide the fork extension and retraction trajectory, ensuring smooth movement, while the fork buffer blocks are specifically used to absorb the impact energy at the moment the forks extend or retract, effectively eliminating metal collision noise, protecting the structure, and extending service life.

[0009] Optionally, the floating driven wheel assembly is arranged perpendicular to the floating drive wheel assembly, and the floating driven wheel assembly floats left, right, up, and down.

[0010] The vertical floating mechanism allows each wheel to independently contact the ground, evenly distribute the load, absorb vertical impacts, and significantly improve the vehicle's stability, smoothness, and safety on uneven surfaces. The horizontal floating mechanism provides lateral adaptability, which helps reduce turning resistance, compensate for errors, absorb lateral impacts, and further enhance the vehicle's maneuverability and structural reliability.

[0011] Optionally, the floating driven wheel assembly includes a swivel caster, which is located on the same straight line as the floating drive wheel assembly.

[0012] The floating driven wheel assembly uses omnidirectional casters as its core component. Their 360° free rotation gives the vehicle excellent responsiveness and extremely low steering resistance, which is key to achieving high maneuverability. More importantly, these omnidirectional casters are designed to be aligned with the floating drive wheel assembly in the same straight line (i.e., aligned in the width direction). This precise layout has multiple advantages: it optimizes the load distribution in the chassis width direction, significantly improving the vehicle's lateral stability in both static and dynamic (especially during steering); it helps achieve a compact frame design; it effectively reduces the torsional load on the body during differential steering, making steering smoother and more controllable; and it also enhances the vehicle's ability to navigate and maintain its posture on lateral uneven surfaces.

[0013] Optionally, the floating drive wheel assembly includes a crossbeam, on which a spring fixing plate, a floating spring, and a spring limiting plate are provided on the side of the driven wheel. The spring fixing plate is fixed to the frame, the spring limiting plate is fixed to the crossbeam, and the floating spring connects the spring fixing plate and the spring limiting plate.

[0014] The spring retaining plate is rigidly fixed to the frame, providing a stable static support point; the spring limiting plate is rigidly fixed to the crossbeam, serving as a dynamic connection point that floats with the crossbeam; the floating spring is pre-compressed and connected between these two plates. The core functions of this mechanism are: 1. Basic floating function: Through the extension and contraction of the spring, it absorbs road impacts, keeps the drive wheels grounded, and improves ride smoothness; 2. Core boosting function: During acceleration, the drive torque causes the crossbeam to tend to lift the driven wheel end, strongly compressing the floating spring. The strong downward reaction force generated by the spring acts directly on that end of the crossbeam, significantly increasing the downforce of the drive wheels (especially the driven wheels) on the ground, greatly improving tire adhesion, effectively suppressing slippage, and thus achieving excellent acceleration performance; During braking / deceleration and load changes, the spring force continuously provides optimized ground pressure, enhancing braking efficiency and dynamic stability.

[0015] Optionally, the spring fixing plate is fixed with a limit screw, and the floating spring is sleeved on the limit screw.

[0016] The limit screw is fixed to the spring fixing plate. Its core function is to provide precise linear motion guidance for the floating spring, ensuring that the spring always extends and contracts along the predetermined trajectory during floating and under force, avoiding bending, deviation or twisting, and ensuring smooth and reliable operation.

[0017] Optionally, the frame has a thin-walled chamber structure for accommodating the floating drive wheel assembly, the floating driven wheel assembly, and electronic components, which are separated by thin walls.

[0018] The frame employs a thin-walled chamber structure as its main body, achieving a highly compact and lightweight design. The core function of this chamber is to integrate and house all key components, including the floating drive wheel assembly, the floating driven wheel assembly, and electronic components, enclosing them within the frame's contours, significantly reducing volume and providing uniform protection. Crucially, these critical components are not haphazardly mixed together, but rather spatially separated by the thin-walled structure that forms the chamber. This separation design is vital: it physically isolates sensitive electronic components from mechanical moving parts that generate vibration, impact, debris, and electromagnetic interference, greatly protecting the reliability of the electronic system; simultaneously, it effectively prevents interference between different moving parts and enhances the local stiffness of the frame.

[0019] Optionally, the fork buffer block is made of a flexible material.

[0020] Flexible materials (such as polyurethane and rubber) possess high elasticity and high damping properties, enabling them to deform significantly upon impact from forks, efficiently absorbing and dissipating impact kinetic energy. This process drastically reduces the peak impact force, eliminates the sharp noise generated by rigid collisions between metal components, and simultaneously reduces the impact load transmitted to the forks and frame structure. This effectively prevents deformation, fatigue damage, and precision degradation caused by repeated impacts, thereby extending equipment life and ensuring operational reliability.

[0021] Alternatively, the frame may be a one-piece molded structure.

[0022] 1. **Extremely Reinforced Structure:** Eliminates weak points and stress concentrations in traditional welded / bolted connections, significantly improving overall rigidity and strength, ensuring superior stability and load-bearing capacity of the chassis under heavy loads, high speeds, steering, and bumpy conditions; 2. **Extremely Compact and Lightweight:** Achieves complex optimized internal cavities and topologies that are difficult to process using traditional methods, maximizing space utilization and reducing weight, while eliminating connecting parts to further simplify the structure; 3. **Ensuring High Precision:** Avoids accumulated assembly errors, ensuring precise consistency between the installation positions of key components and internal isolation cavities, improving overall machine performance; 4. **Enhanced Reliability and Durability:** Eliminates potential faults such as weld cracking and bolt loosening, significantly extending service life.

[0023] Beneficial effects

[0024] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0025] This invention provides a chassis for a forklift that utilizes a floating drive wheel assembly and a floating driven wheel assembly to achieve a differential drive structure. This results in a smaller turning radius, more flexible operation, and improved path tracking accuracy and overall motion flexibility. The floating drive wheel assembly is hinged to the chassis via a pivot shaft and has upper and lower elastically arranged drive and driven wheels at both ends, enhancing the stability and adaptability of the vehicle body under load changes or high-speed operation. The fork guide blocks and buffer blocks installed in the fork housing slots effectively reduce collision noise between metal parts during fork extension and retraction, improving operational smoothness and structural durability. The overall structure is compact and has high space utilization, significantly improving the stability, power response speed, and operating efficiency of the forklift under complex working conditions. It is suitable for automated logistics and warehousing scenarios with higher efficiency and higher precision requirements. Attached Figure Description

[0026] Figure 1 A schematic diagram of the chassis structure of a stealthy forklift, as proposed in an embodiment of this utility model;

[0027] Figure 2A schematic diagram of the structure of a floating drive wheel assembly of a chassis of a lurking forklift, as proposed in an embodiment of this utility model;

[0028] Figure 3 A cross-sectional schematic diagram of a floating drive wheel assembly of a chassis of a lurking forklift, as proposed in an embodiment of this utility model;

[0029] Figure 4 A schematic diagram of the structure of a floating driven wheel assembly of a chassis of a lurking forklift, as proposed in an embodiment of this utility model;

[0030] 1. Frame; 11. Fork Reception Slot; 2. Floating Drive Wheel Assembly; 20. Drive Drive Wheel; 21. Spring Fixing Plate; 22. Floating Spring; 23. Spring Limiting Plate; 24. Limiting Screw; 25. Crossbeam; 26. Drive Driven Wheel; 27. Drive Motor; 28. Pivot Shaft; 29. ​​Drive Mounting Plate; 3. Floating Driven Wheel Assembly; 31. Driven Wheel Carrier; 32. Universal Caster; 33. Oil-Free Bearing; 34. Wheel Carrier Hinge Shaft; 35. Universal Caster Locking Nut; 4. Fork Guide Block; 5. Fork Buffer Block. Detailed Implementation

[0031] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0032] Example

[0033] Combined with appendix Figure 1 A chassis for a stealth forklift, comprising a frame 1: a basic support, whose core function is compact structural integration (accommodating all components) and providing overall rigidity / stability. (In conjunction with...) Figure 1 The arrow indicates the direction of travel.

[0034] The frame 1 is tightly equipped with a floating drive wheel assembly 2, a floating driven wheel assembly 3 and several fork receiving slots 11. The floating drive wheel assembly 2 is symmetrically and parallelly arranged and is a differential drive structure. The floating drive wheel assembly 2 (core drive unit): differential drive structure: its core function is to achieve flexible steering (reduce the turning radius and improve tracking accuracy).

[0035] Combined with appendix Figure 2 , 3The floating drive wheel assembly 2 is hinged to the frame 1 via a pivot shaft 28. The pivot shaft 28, hinged to the frame 1, enables the entire drive wheel assembly to float, adapting to uneven ground. At each end of the pivot shaft 28 are a vertically elastic driven wheel 26 and a vertically elastic drive wheel 20. The vertically elastic drive wheel 20 and driven wheel 26 (spring-assisted mechanism) primarily enhance power performance. The elastic springs provide additional downforce during acceleration to increase traction (anti-slip), and absorb impact and maintain traction during deceleration / braking (anti-lock / sideslip), greatly improving acceleration / deceleration performance and dynamic stability.

[0036] The floating driven wheel assembly 3 and the wheel frame hinge shaft 34 are hinged to the frame 1. The floating driven wheel assembly 3 and the wheel frame hinge shaft 34 are hinged to the frame 1. They also achieve the floating function, which helps to adapt to the terrain, share the load, and enhance the overall stability.

[0037] The fork receiving groove 11 is equipped with a fork guide block 4 and a fork buffer block 5. The core function of the fork guide block 4 in the fork receiving groove 11 is precise guidance, ensuring the correct and smooth extension and retraction trajectory of the forks, reducing friction and jamming. The core function of the fork buffer block 5 is energy absorption and noise reduction, eliminating collision noise and impact when the forks are in position / starting, achieving silent operation and protecting the structure.

[0038] Combined with appendix Figure 4 The floating driven wheel assembly 3 is positioned perpendicular to the floating drive wheel assembly 2, and floats horizontally and vertically. This defines the spatial orientation of the driven wheel assembly within the chassis layout. The axis of the floating driven wheel assembly 3 (typically a swivel wheel or caster) is arranged perpendicular (typically 90 degrees) to the axis of the floating drive wheel assembly 2. This vertical arrangement ensures that the drive wheels provide the primary driving force (forward / reverse) and steering force via differential rotation, while the driven wheels primarily handle free movement and bear lateral forces. This allows for smooth steering: when the drive wheels rotate differentially to achieve a turn, the vertically arranged driven wheels naturally follow the steering trajectory, providing minimal steering resistance. It also maintains directional stability: during straight-line driving, the vertically arranged driven wheels help stabilize the vehicle body and prevent unnecessary sideslip. It enables omnidirectional motion capability (basic): laying the foundation for potentially more complex movements (such as lateral movement, if the driven wheels are also drive wheels or special casters), but in this design, its responsiveness is the primary focus. The structure, where the driven wheel frame 31 is hinged to the frame 1 via the wheel frame hinge shaft 34, allows the driven wheel frame 31 to undergo a certain degree of displacement relative to the frame 1 body, thus realizing the floating characteristic of the floating driven wheel.

[0039] "Up-down floating" means that the component can move vertically (Z-axis) relative to the frame 1. "Left-right floating" means that the component can move horizontally (Y-axis) relative to the frame 1 (usually with a slight oscillation around the hinge point).

[0040] The floating driven wheel assembly 3 includes a swivel caster 32, which is located on the same straight line as the floating drive wheel assembly 2. The "swivel caster 32" is a common type of caster, characterized by the fact that the wheel frame can rotate freely 360° around an axis perpendicular to the ground (steering axis), while the wheel itself can roll around its own axis.

[0041] The floating driven wheel assembly 3 also includes a driven wheel frame 31, an oilless bearing 33, a wheel frame hinge shaft 34, and a locking nut 35. The driven wheel frame 31 is hinged to the cavity of the frame 1 through the oilless bearing 33 and the wheel frame hinge shaft 34, and the locking nut 35 fixes the swivel caster 32.

[0042] The floating drive wheel assembly 2 includes a crossbeam 25, which is the core load-bearing and connecting frame of the floating drive wheel assembly 2. It rigidly connects the drive wheel 20 and the driven wheel 26 (usually located at both ends of the crossbeam 25), integrating them into a single unit. On one side of the driven wheel 26 of the crossbeam 25, there is a spring fixing plate 21, a floating spring 22, and a spring limiting plate 23. The spring fixing plate 21 provides a fixed and reliable connection point (upper end) for the floating spring 22. The force applied to the spring system by the frame 1 (mainly the downward pressure exerted by the spring on the drive wheel) or the spring reaction force is transmitted to the main body of the frame 1 through this plate. The spring fixing plate 21 is fixed to the frame 1, and the spring limiting plate 23 is fixed to the crossbeam 25 and moves with the crossbeam 25. The floating spring 22 connects the spring fixing plate 21 and the spring limiting plate 23.

[0043] The floating drive wheel assembly 2 also includes drive wheels 20, driven wheels 26, a drive motor 27, and a drive mounting plate 29. There are four drive wheels 20, arranged in pairs, with each pair connected to either side of the drive motor 27. The drive motor 27 is a differential motor, characterized by its simple structure and flexible movement. The drive motor 27 is fixed to the drive mounting plate 29. The driven wheels 26 are also swivel casters 32.

[0044] Achieving "spring boost":

[0045] During acceleration: The motor applies a driving torque, and the drive wheels generate a force pushing backward against the ground (according to Newton's third law, the ground's reaction force on the drive wheels is the traction force). This action causes the crossbeam 25 to generate a torque around the fulcrum axis 28, attempting to lift one side of the driven wheel 26 (lever effect). At this time, the floating spring 22 is further compressed, and its downward reaction force acts on the driven wheel 26 end of the crossbeam 25 through the spring limiting plate 23, significantly increasing the downforce of the drive wheels (especially the driven wheels) on the ground. This greatly improves the adhesion between the tires and the ground, effectively preventing the drive wheels from slipping, thus allowing for the application of greater driving force and achieving stronger acceleration performance.

[0046] During braking / deceleration: The braking process generates a forward inertial force, attempting to push the drive wheels forward. At this time, the crossbeam 25 is subjected to a counter-torque (attempting to press down on one side of the driven wheel 26), and the floating spring 22 is stretched or partially released, but still maintains a certain tension. The spring force continuously provides downforce, maintaining tire traction, helping to prevent lock-up and sideslip, and improving braking performance and stability.

[0047] When the load changes: When the center of gravity changes due to the forks carrying or unloading goods, the springs can automatically adjust the compression amount to dynamically adapt and maintain the optimal ground pressure of the drive wheels.

[0048] A limiting screw 24 is fixed to the spring fixing plate 21, and the floating spring 22 is fitted onto the limiting screw 24. The shaft of the limiting screw 24 passes through the center hole of the floating spring 22, providing a precise and stable linear motion trajectory for the spring's extension and contraction. This effectively prevents the floating spring 22 from bending, shifting laterally, or twisting during operation, ensuring that the spring force is always transmitted along the designed direction (usually the vertical direction), avoiding additional friction, wear, jamming, or efficiency loss caused by spring instability, and guaranteeing the smoothness and reliability of the floating and pressurizing actions.

[0049] Lower travel limit (preventing overstretching): The head of the screw (or mating nut) is positioned above the spring (away from the spring retaining plate 21). When the floating spring 22 is stretched (e.g., during braking or encountering a pothole), the spring limiting plate 23 (moving with the crossbeam 25) moves upward and eventually abuts against the screw head. This sets the maximum stretching stroke of the floating spring 22, preventing the spring from being overstretched or even straightened out, thus protecting the spring.

[0050] Upper limit of travel (preventing over-compression): Although the main description focuses on the spring being fitted onto the screw, in conjunction with the preceding structure, when the floating spring 22 is strongly compressed (e.g., during rapid acceleration or encountering a large protrusion), the spring limiting plate 23 will move downwards and eventually abut against the spring fixing plate 21 or other structures (such as the screw mounting base). The length of the limiting screw 24 and the position of its head indirectly define the maximum compression space of the spring (although the primary limiting may be accomplished by other structures), preventing the spring from being completely crushed (pressed down) leading to rigid impact and permanent deformation of the spring.

[0051] The frame 1 has a thin-walled chamber structure. The chambers house the floating drive wheel assembly 2, the floating driven wheel assembly 3, and electronic components. The floating drive wheel assembly 2, the floating driven wheel assembly 3, and the electronic components are separated by thin walls. The frame 1 has a "mountain"-shaped structure. There are chambers on both sides to house the floating drive wheel assembly 2. Behind the chambers of the floating drive wheel assembly 2, there is a vertical chamber for the floating driven wheel assembly 3. The chambers of the floating drive wheel assembly 2 are symmetrical, and the middle chamber is for electronic components and other mechanical components. The structure is simple and compact.

[0052] The fork buffer block 5 is made of a flexible material. In this embodiment, the flexible material can be polyurethane (PU), rubber (natural or synthetic), silicone, high-elasticity engineering plastics, etc.

[0053] The frame 1 is a one-piece molded structure. The main body of the frame 1 (including its thin-walled chambers, internal partitions, mounting bosses, reinforcing ribs and other key features) is a single, continuous and seamless component manufactured in one piece through a manufacturing process (such as large precision casting - die casting / gravity casting, injection molding - for high-strength engineering plastics, or integral forging / machining - higher cost but excellent performance).

[0054] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A chassis frame for a stealthy forklift, characterized in that, The vehicle includes a frame, within which a floating drive wheel assembly, a floating driven wheel assembly, and several fork receiving slots are tightly arranged. The floating drive wheel assemblies are symmetrically and parallelly arranged and have a differential drive structure. The floating drive wheel assemblies are hinged to the frame via a pivot shaft. At each end of the pivot shaft are a driven wheel and a driving wheel that are elastically arranged vertically. The wheel frame hinge shaft of the floating driven wheel assembly is hinged to the frame. The fork receiving slots are provided with fork guide blocks and fork buffer blocks.

2. A chassis for a latent fork lift truck according to claim 1, wherein, The floating driven wheel assembly is arranged perpendicular to the floating drive wheel assembly, and the floating driven wheel assembly floats left, right, up, and down.

3. A chassis for a stow fork truck as defined in claim 2 wherein, The floating driven wheel assembly includes swivel casters, and the swivel casters and the floating drive wheel assembly are located on the same straight line.

4. A chassis for a stow fork truck as defined in claim 1, wherein, The floating drive wheel assembly includes a crossbeam. A spring fixing plate, a floating spring, and a spring limiting plate are provided on one side of the drive driven wheel of the crossbeam. The spring fixing plate is fixed to the vehicle frame, the spring limiting plate is fixed to the crossbeam, and the floating spring connects the spring fixing plate and the spring limiting plate.

5. A chassis for a stow fork truck as defined in claim 4 wherein, The spring fixing plate is fixed with a limit screw, and the floating spring is sleeved on the limit screw.

6. A chassis for a stow fork truck as defined in claim 1, wherein, The vehicle frame has a thin-walled chamber structure, which is used to house the floating drive wheel assembly, the floating driven wheel assembly, and electronic components. The floating drive wheel assembly, the floating driven wheel assembly, and the electronic components are separated by thin walls.

7. A chassis for a stow fork truck as defined in claim 1 wherein, The fork buffer block is made of flexible material.

8. A latent fork truck chassis according to any one of claims 1 to 7, characterized in that, The frame is a one-piece molded structure.

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