A four-wheel differential chassis structure and its working method

Abstract

This invention discloses a four-wheel differential walking chassis structure and its working method. The four-wheel differential walking chassis structure includes three parts: a frame (1), a wheel system (2), and a suspension (3). The frame part (1) is divided into an upper frame (11) and a lower frame (12). The upper surface of the upper frame (11) is used to support and install functional components. On the left and right sides of the front beam (111) and the rear beam (112) of the frame part (1), a total of four outrigger hydraulic cylinders (113) are provided. During vehicle transportation, the piston rod of the outrigger hydraulic cylinder (113) does not extend. During engineering operations, the piston rod extends so that the bottom of the piston rod contacts the ground, the overall vehicle height is raised, the tires are lifted off the ground, and the overall vehicle support stability is enhanced. This invention can self-adjust when traveling on complex potholes and uneven roads, which can well ensure the balance and stability of the whole vehicle, and has good passability and road adaptability.

Description

Technical Field

[0001] This invention applies to the field of general mobile chassis for engineering transportation, specifically a four-wheel differential walking chassis structure and its working method. Background Technology

[0002] Power transmission and transformation projects are a very important part of the power system, involving the transmission, transformation, and distribution of electricity. During the construction process, the use of handling equipment is crucial for improving efficiency, reducing manpower input, and ensuring the safety and quality of the construction. According to relevant literature, research on engineering transport vehicles has made some progress, and their application areas are mainly concentrated in agriculture, forestry, military, engineering construction, and fire protection.

[0003] However, current transport equipment is not suitable for the construction environment and requirements of power transmission and transformation projects. Agricultural transport equipment has a relatively simple structure, low level of automation and intelligence, and some equipment is manually pushed, resulting in high labor intensity and low work efficiency. Military, engineering construction, and fire transport equipment is bulky and heavy, unable to adapt to narrow roads and limited construction environments, and has low movement speed and transport efficiency, poor flexibility and road adaptability. It has poor passage through complex and uneven road surfaces, lacks good obstacle crossing ability, and is prone to overturning and insufficient support during operation.

[0004] In summary, there is a lack of specialized transportation equipment on the market for handling engineering materials such as cement, sand, gravel, and small steel pieces in power transmission and transformation projects. Therefore, it is essential to develop a miniaturized, high-performance, and highly adaptable mobile chassis for engineering transportation vehicles, which is particularly suitable for projects with limited working space and complex road conditions, such as power transmission and transformation projects.

[0005] Four-wheel differential drive chassis are a common type of mobile chassis, widely used due to their high mobility and small turning radius. For projects with limited space and complex road conditions, such as power transmission and transformation projects, chassis with excellent mobility and the ability to climb slopes and overcome obstacles are essential. Currently, commercially available transport equipment suffers from poor passability due to chassis limitations, making it prone to overturning when turning or driving on slopes, and insufficient support when traversing uneven terrain or ditches. Therefore, an improved, highly adaptable four-wheel differential drive chassis would be suitable for a wider range of applications.

[0006] Currently, a Chinese patent has been found: "An Adaptive Vehicle-Ground Dual-Use Vehicle Chassis Strength Testing System", publication number CN117848736A. This system includes: an actuator comprising a load-bearing device, a loading device, and a leveling device; the load-bearing device is mounted on the rear beam of the vehicle; the loading device is fixed to the load-bearing device and hinged to a locking mechanism; the loading device applies load to the locking mechanism; the leveling device is positioned between the load-bearing device and the ground; the height of the leveling device is adjustable to adjust the loading tilt angle of the loading device; a control system including a controller electrically connected to both the loading device and the leveling device; the controller controls the loading load of the loading device and also controls the height of the leveling device to adjust its loading tilt angle; and a health monitoring system for monitoring the stress and deformation of the rear beam, locking mechanism, and actuator during testing and predicting potential faults. However, this patent has poor passability and is prone to overturning when turning or driving on slopes.

[0007] In addition, Chinese patent CN219990955U, entitled "A Self-Leveling Obstacle-Crossing Device and Vehicle Chassis for Special Equipment," includes a leveling bracket, a drive assembly, and a wheel assembly. The leveling bracket has an arched structure with a hollow gear cavity inside. The drive assembly includes a gear set disposed within the gear cavity. In the gear set, the main gear is mounted at the center of the arched portion of the arched structure, and output gears are mounted at the two legs of the arched structure. The main gear and the output gear are driven by a driven wheel. The main gear is mounted on a main drive shaft, and the input end of the main drive shaft is connected to the output side of a universal joint. The input side of the universal joint is used to connect to the vehicle body. The wheel assembly includes two wheel mounting structures, and the two output gears drive the two wheel mounting structures to rotate through the drive shaft. This self-leveling obstacle-crossing device and vehicle chassis for special equipment has the advantages of self-leveling capability, good smoothness and stability, and strong obstacle-crossing ability. However, the structure of this patent is complex and its stability is poor. Summary of the Invention

[0008] To address the shortcomings of the existing technology, this invention proposes a four-wheel differential driving chassis structure and its working method. This four-wheel differential driving chassis structure is rationally designed and conducive to improving stability.

[0009] A four-wheel differential travel chassis structure is characterized by comprising three parts: a frame, a wheel system, and a suspension. The frame is divided into an upper frame and a lower frame. The upper surface of the upper frame is used to support and install functional components. Four outrigger hydraulic cylinders are provided on the left and right sides of the front and rear beams of the frame. During vehicle transportation, the piston rods of the outrigger hydraulic cylinders do not extend. During engineering operations, the piston rods extend so that the bottom of the piston rods contacts the ground, raising the overall vehicle height, lifting the tires off the ground, and enhancing the overall support stability of the vehicle.

[0010] The lower frame is welded to the lower surface of the upper frame. The lower frame is used to connect the upper frame, suspension and wheel system. The lower frame is constructed by welding suspension connecting beams, vertical beams and short crossbeams.

[0011] Two vertically spaced vertical beams are vertically welded between the two parallel upper and lower suspension connecting beams. The two suspension connecting beams and the two vertical beams form a set of vertical components. Multiple parallel short crossbeams are provided between the two sets of spaced vertical components.

[0012] Each suspension connecting beam has lugs spaced apart on its left and right sides. The lugs have through holes, and a first pin is installed in the through holes of the two lugs. A first bearing sleeve is fitted on the first pin.

[0013] Preferably, the aforementioned wheel system consists of four components: a wheel system support frame, a hydraulic motor, a reducer, and wheels. The wheel system support frame is welded from sheet metal, and a second pin is installed at each of the four diagonal corners of the wheel system support frame. A second bearing sleeve is fitted on the second pin. The hydraulic motor, reducer, and wheels are connected to the wheel system support frame by bolts. By driving the output shaft of the hydraulic motor to rotate, the reducer and wheels are driven to rotate, providing driving power for the chassis.

[0014] Preferably, the aforementioned suspension uses a double wishbone independent suspension. The double wishbone suspension has two A-shaped control arms, upper and lower. The upper control arm is formed by welding two mirror-symmetrical connecting rods to a central support rod. One end of the upper control arm is hinged to the upper part of the suspension connecting beam, and the other end is hinged to the upper part of the wheel support frame. The lower control arm is formed by welding two mirror-symmetrical connecting rods to a central support plate. One end of the lower control arm is hinged to the lower part of the suspension connecting beam, and the other end is hinged to the lower part of the wheel support frame. At this time, one end of the double wishbone suspension is hinged to the vehicle frame, and the other end can swing up and down relative to the wheel support frame around a pivot. A shock absorber is installed in the middle of the upper and lower control arms. The upper end of the shock absorber is connected to the short crossbeam and the vehicle frame through the upper shock absorber lug, and the lower end is connected to the support plate of the lower control arm through the lower shock absorber lug. It plays a role in buffering impact when the wheel moves up and down, ensuring the balance and stability of the chassis.

[0015] The beneficial technical effects of this invention patent are as follows:

[0016] The compact size and volume design better meet the requirements of construction scenarios in narrow roads and limited spaces. The four-wheel differential independent drive system increases power supply, enhances flexibility, reduces turning radius, and improves vehicle speed and transportation efficiency. The double wishbone independent suspension absorbs lateral impact loads simultaneously from both upper and lower control arms, resulting in high lateral stiffness and excellent lateral support during cornering. This enhances handling of the wheel system and allows for self-adjustment of the height difference between the front and rear wheels and the left and right side wheels, providing good road adaptability and improving the vehicle's obstacle-crossing and uneven terrain capabilities. The parallelogram structure formed by the two control arms prevents tire tilting during vertical movement, ensuring strong road contact. Furthermore, its compact layout, compared to other suspension systems, effectively lowers the overall chassis center of gravity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the four-wheel differential walking chassis mechanism of the present invention;

[0018] Figure 2 This is a bottom view of the four-wheel differential walking chassis mechanism of the present invention;

[0019] Figure 3 This is a schematic diagram of the underframe structure;

[0020] Figure 4 This is a schematic diagram of the suspension components;

[0021] Figure 5 This is a schematic diagram of the gear train assembly structure;

[0022] Figure 6 This is a schematic diagram illustrating the driving situation when the present invention crosses obstacles;

[0023] Figure 7 This is a schematic diagram of the invention using a single-sided bridge.

[0024] Figure 8 This is a schematic diagram illustrating the present invention in the case of an uneven road surface;

[0025] Figure 9 This is a three-dimensional structural diagram of the forklift mechanism of the present invention;

[0026] Figure 10 This is a three-dimensional structural diagram of the forklift mechanism for removing the cargo box according to the present invention;

[0027] Figure 11 yes Figure 10 A partial view;

[0028] Figure 12 This is a schematic diagram of the forklift mechanism with the cargo box lying flat.

[0029] Figure 13 This is a schematic diagram of a control system for a forklift mechanism;

[0030] Figure 14 This is a schematic diagram of another control mechanism for forklifts;

[0031] Figure 15 This is a schematic diagram of the overall structure of the present invention;

[0032] Attached reference numerals: 1. Frame section, 11. Upper frame, 12. Lower frame, 111. Front beam, 112. Rear beam, 113. Outrigger hydraulic cylinder, 121. Suspension connecting beam, 122. Vertical beam, 123. Short crossbeam, 124. First pin, 125. First bearing sleeve, 126. Bolt, 127. End cap; 2. Wheel system section, 21. Wheel system support frame, 22. Hydraulic motor, 23. Reducer, 24. Wheel, 25. Second pin, 26. First bearing sleeve, 27. End cap, 28. Bolt, 29. Connecting bolt; 3. Suspension section, 31. Linkage, 32. Support rod, 33. Support plate; 4. Shock absorber, 41. Upper shock absorber lug, 42. Lower shock absorber lug.

[0033] A01, I-beam support frame; A11, Leftmost rotating pin; A12, Rightmost rotating pin; A13, Leftmost rotating pin; A14, Rightmost rotating pin; A15, First sliding bearing; A16, Second sliding bearing; A02, Forklift mast; A21, Forklift mast body; A22, Leftmost lifting lug assembly; A23, Rightmost lifting lug assembly; A24, Leftmost lifting lug assembly; A25, Rightmost lifting lug assembly; A26, Bottom support plate; A03, Leftmost multi-stage hydraulic cylinder; A31, Leftmost proportional valve; A32, Leftmost position sensor; A33, Leftmost spherical bearing; A34, Leftmost spherical bearing; A35, Leftmost rotating pin. A04, Right-side multi-stage hydraulic cylinder; A41, Right-side proportional valve; A42, Right-side position sensor; A43, Right first joint bearing; A44, Right second joint bearing; A45, Right third rotary pin; A05, Forklift lifting hydraulic cylinder; A51, Central proportional valve; A52, Central position sensor; A06, Forklift rack; A61, Outer frame assembly; A62, Inner frame assembly; A63, Upper load-bearing frame assembly; A64, Connecting rod; A65, Left fork; A66, Right fork; A67, Roller; A07, Loadable / unloadable cargo box; A71, Positioning pin; A08, Control cabinet; A09, Engine; A10, Hydraulic pump;

[0034] K5 - Hydraulic transformer; K6 - Electromagnetic directional valve; K9 - Hydraulic power cylinder; K12 - Servo proportional valve; K13 - Pressure sensor; K14 - Hydraulic transformer distributor plate angle sensor; K15 - Hydraulic controller. Detailed Implementation

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. Furthermore, other drawings can be obtained based on these drawings.

[0036] This invention provides a four-wheel differential walking chassis mechanism and its working method.

[0037] The four-wheel differential chassis mechanism comprises three parts: a frame 1, a wheel system 2, and a suspension 3. The frame 1 consists of an upper frame 11 and a lower frame 12. The upper frame 11 includes a front beam 111, a rear beam 112, and several crossbeams and longitudinal beams connecting the front beam 111 and the rear beam 112. The upper surface of the upper frame 11 is mainly used to support and install other functional components (such as forklift mechanisms, excavator robotic arms, power mechanisms, etc.). The frame beams of the upper frame 11 use cold-formed hollow steel with square cross sections as crossbeams or longitudinal beams. The crossbeams and longitudinal beams are welded together, which can improve the load-bearing capacity while reducing the overall weight and ensuring the overall strength of the frame. On the left and right sides of the front beam 111 and rear beam 112 of the upper frame 11, a total of four outrigger hydraulic cylinders 113 are arranged. During vehicle transportation, the piston rods of the four outrigger hydraulic cylinders 113 do not extend. During engineering operations, the piston rods extend to a certain length. At this time, the bottom of the piston rod contacts the ground, the height of the whole vehicle is raised, the tires are lifted off the ground, the support range is expanded, and the support stability of the whole vehicle is enhanced.

[0038] The upper surface of the lower frame 12 is welded to the lower surface of the upper frame 11, mainly used to connect the upper frame, suspension, and wheel system. The lower frame 12 (e.g.) Figure 3 As shown, it is constructed by welding together a suspension connecting beam 121, a vertical beam 122 and a short crossbeam 123. Specifically, two vertical beams 122 are welded vertically between two parallel upper and lower suspension connecting beams 121. The two suspension connecting beams 121 and the two vertical beams 122 form a set of vertical components. Multiple parallel short crossbeams 123 are welded between the two sets of spaced vertical components.

[0039] Each suspension connecting beam has lugs spaced apart on its left and right sides. The lugs have through holes. A first pin 124 is installed in the through holes of two lugs on the same suspension connecting beam and on the same side. A first bearing sleeve 125 is fitted on the first pin 124, and a first end cap 127 is installed on one side of the first pin with a first bolt 126 for axial fixation.

[0040] Among them, gear train part 2 (such as Figure 4(As shown) It consists of four components: wheel support frame 21, hydraulic motor 22, reducer 23, and wheel 24. The wheel support frame is welded from sheet metal, and a second pin 25 is installed at each of its four diagonal corners. A second bearing sleeve 26 is fitted on the second pin. The axis of the second pin is parallel to that of the first pin. A second end cap 27 and a second bolt 28 are installed at one end of the pin for axial fixation. A series of bolt holes are machined on the support frame 21 for installing bolts to connect with the hydraulic motor. The hydraulic motor is connected to the reducer, and the reducer is connected to the wheel rim using bolts 29. By driving the output shaft of the hydraulic motor 22 to rotate, the reducer 23 and the wheel 24 are driven to rotate, providing driving power for the chassis.

[0041] The suspension section 3 uses a double wishbone independent suspension. The double wishbone suspension has two A-shaped control arms, upper and lower. The upper control arm is formed by welding two mirror-symmetrical connecting rods 31 to a central support rod 32. Both ends of the connecting rods 31 have bushings that engage with pins (the axis lines of the connecting rods 31, support rods 32, and bushings are in the same plane). One end of the connecting rod is connected to the upper part of the suspension connecting beam 121 (first pin 124), and the other end is connected to the upper part of the wheel support frame 21 (second pin 25). The lower control arm is formed by welding two mirror-symmetrical connecting rods 31 to a central support plate 33 (the axis lines of the connecting rods 31 and support plate 33 are in the same plane). One end of the connecting rod is connected to the lower part of the suspension connecting beam 121. (First pin 124) is connected, and the other end is connected to the lower part of the wheel support frame 21 (second pin 25). At this time, one end (preferably the large end) of the double wishbone suspension is connected to the frame 1, and the other end (preferably the small end) is connected to the wheel support frame 21. The two control arms are equipped with shock absorbers 4 in the middle. The upper end of the shock absorber is connected to the frame 1 through the upper shock absorber ear 41, and the lower end is connected to the support plate 33 of the lower control arm through the lower shock absorber ear 42. It plays a role in buffering the impact when the wheel 24 moves up and down. The above-mentioned A-shaped structure of the two control arms can avoid the installation space of the hydraulic motor 22, etc., making the equipment installation more compact, and also making the mechanism structure more stable.

[0042] By using special installation positions and heights of the left front wheel system, right front wheel system, left rear wheel system, right rear wheel system, suspension system, and shock absorbers, the following technical specifications can be achieved: Over-bump height: maximum vertical height 10 cm; maximum height over a single-sided bridge: 10 cm; maximum tire height difference over uneven road surfaces: 20 cm.

[0043] like Figure 6 As shown, when the chassis travels to bumpy terrain, the front two wheels contact the ground obstacles, the corresponding shock absorber springs are compressed, the suspension and wheel system are raised relative to the frame, and the chassis begins to cross the bumps, giving it a certain ability to cross bumps.

[0044] like Figure 7 As shown, when the chassis is driving on a single-sided bridge, the two side wheels contact the bridge surface, forming a certain height difference with the other side tire, giving the chassis a certain ability to pass through a single-sided bridge.

[0045] like Figure 8 As shown, when the chassis travels on an uneven road surface, the right front wheel system contacts the raised part of the ground and rises relative to the frame, while the left rear wheel system sinks into the groove. The left front and right rear wheel systems simultaneously provide support to the frame through the shock absorption system, maintaining the chassis balance and preventing rollover.

[0046] The upper surface of the upper frame 11 supports the forklift mechanism A, the excavator robotic arm B, the power mechanism C, etc.

[0047] The forklift mechanism A includes an I-beam support frame A01, with a forklift mast A02 hinged to its front end. The left and right sides of the middle of the forklift mast A02 are respectively hinged to the front ends of a left-side multi-stage hydraulic cylinder A03 and a right-side multi-stage hydraulic cylinder A04. The rear ends of the left-side and right-side multi-stage hydraulic cylinders A03 and A04 are hinged to the rear end of the I-beam support frame A01. The bottom of the forklift mast A02 is fixedly connected to the rear end (cylinder body) of a forklift lifting hydraulic cylinder A05. Next, the head of the forklift lifting hydraulic cylinder A05 (referring to the free end of the telescopic rod) is fixedly connected to the top of the forklift rack A06. The front end of the forklift rack A06 is connected to the loading and unloading box A07 via the positioning pin A71. When it is necessary to fix the loading and unloading box A07 to the forklift rack A06, it is fixed by the positioning pin A71. When it is not necessary to fix the loading and unloading box A07 to the forklift rack A06, the positioning pin A71 is removed and the loading and unloading box A07 is taken off.

[0048] The forklift mast A02 mentioned above includes a forklift mast body A21. The left and right sides of the middle part of the forklift mast body A21 are welded to the left first lifting lug assembly A22 and the right first lifting lug assembly A23, respectively. The bottom of the forklift mast body A21 is welded to the left second lifting lug assembly A24 and the right second lifting lug assembly A25. The bottom of the forklift mast body A21 is welded to the bottom support plate A26. The tail (referring to the cylinder body) of the forklift lifting hydraulic cylinder A05 is fixedly connected to the bottom support plate A26.

[0049] The forklift rack A06 mentioned above includes an outer frame assembly A61, an inner frame assembly A62 welded to the inside of the outer frame assembly A61, an upper load-bearing frame assembly A63 welded to the top of the inner frame assembly A62, a connecting rod A64 connected to the middle of the outer frame assembly A61, a left fork A65 and a right fork A66 slidably connected to the connecting rod A64, both the left fork A65 and the right fork A66 are L-shaped, and their upper parts are slidably connected to the connecting rod A64, the inner frame assembly A62 is connected to a roller A67, the roller A67 is limited to rolling in the guide rail groove of the forklift mast body A21.

[0050] The aforementioned loadable cargo box A07 is welded from steel plates and angle steel, and its dimensions are consistent with those of the outer frame assembly A61. It is fixedly connected by a positioning pin A71, ensuring that the loadable cargo box A07 is constrained by the outer frame assembly A61, the left fork A65, and the right fork A66 around its perimeter during the movement of the device.

[0051] Combination Figure 12 In forklift mode, the device uses the forklift function to unload the loadable box A07, starts the lifting hydraulic cylinder A05, and lifts the upper load-bearing frame assembly A63 which is fixed to the top of the piston rod of the lifting hydraulic cylinder A05 with a flange. The roller A67 rolls along the guide rail groove of the forklift mast body A21.

[0052] In this embodiment, the left second lifting lug A24 and the right second lifting lug A25 are connected to the left and right semi-circular protrusions at the front end of the I-shaped support frame A01 through the left first rotating pin A11, the first sliding bearing A15 and the right first rotating pin A12, the second sliding bearing A16, respectively, so as to realize the rotation setting of the forklift mast A02.

[0053] In this embodiment, the two ends of the left multi-stage hydraulic cylinder A03 are rotatably connected to the left first joint bearing A33, the left second rotating pin A13, and the left second joint bearing A34 and the left third rotating pin A35; the two ends of the right multi-stage hydraulic cylinder A04 are rotatably connected to the right first joint bearing A43, the right second rotating pin A14, the right second joint bearing A44, and the right third rotating pin A45, thereby realizing the rotational setting of the multi-stage hydraulic cylinders on both the left and right sides.

[0054] One embodiment of forklift mechanism A control, combined with Figure 13 Simultaneously, the left-side multi-stage hydraulic cylinder A03 and the right-side multi-stage hydraulic cylinder A04 can be activated, shortening the length of the hydraulic cylinders. The left-side multi-stage hydraulic cylinder A03 rotates around the left first joint bearing A33 and the left second rotating pin A13, while the right-side multi-stage hydraulic cylinder A04 rotates around the right first joint bearing A43 and the right second rotating pin A14. This causes the forklift mast A02 to rotate around the left first rotating pin A11, the first sliding bearing A15, the right first rotating pin A12, and the second sliding bearing A16, adjusting the center of gravity of the forked goods so that it is biased towards the center of the device. This ensures the reliability and stability of the device in loading and unloading goods.

[0055] In this embodiment, combined with Figure 11 , Figure 12 and Figure 13In forklift mode, the device uses the forklift function to load the unloading box A07. It activates the left-side multi-stage hydraulic cylinder A03 and the right-side multi-stage hydraulic cylinder A04, causing the forklift mast A02, forklift lifting hydraulic cylinder A05, forklift rack A06, and unloading box A07 to rotate around the left-side rotating pin A11 and the right-side rotating pin A12. Precise control of the forklift section's rotation is achieved through the combined action of the left-side proportional valve A31, left-side position sensor A32, right-side proportional valve A41, and right-side position sensor A42, resulting in a 90-degree rotation of the aforementioned structure, transforming the device from a vertical to a horizontal state. The outer frame assembly A61 is connected to the head of the unloading box A07 via a positioning pin A71, enabling the switching between forklift and freight modes.

[0056] In this embodiment, in freight mode, the device can activate the forklift lifting hydraulic cylinder A05, causing the forklift rack A06, the loadable and unloadable box A07, and the goods to move to the left, thereby shifting the center of gravity of the device and the goods to the left and bringing the center of gravity closer to the center to ensure the reliability and stability of the device in transporting goods.

[0057] In this embodiment, there is a certain gap between the I-shaped support frame A01 and the forklift mast A02 for the arrangement of hydraulic cylinder oil pipes, ensuring that the hydraulic cylinder oil pipes do not interfere with each other when the device is running.

[0058] In this embodiment, both the forklift mast A02 and the forklift rack A06 have a hollow design. While meeting the carrying capacity, the various components are tightly connected, reducing the size of the device, thereby reducing the weight of the device and lowering the energy consumption of movement.

[0059] Combination Figure 13 When the device is equipped with a power transmission system, an external control cabinet A08, engine A09, and hydraulic pump A10 are required. The control cabinet A08 controls the engine A09 to provide power for the device's switching. The output shaft of the engine A09 drives the hydraulic pump A10 to work. The hydraulic pump A10 distributes hydraulic oil to the left multi-stage hydraulic cylinder A03, the right multi-stage hydraulic cylinder A04, and the forklift lifting hydraulic cylinder A05. First, the control cabinet A08 sends a signal to simultaneously control the left proportional valve A31 and the right proportional valve A41 to control the direction, flow, and speed of the hydraulic oil, thereby achieving the tilting of the forklift mast A02. During this process, feedback from the left position sensor A32 and the right position sensor A42 can be used to achieve precise control. Second, the control cabinet A08 sends a signal to control the central proportional valve A51 to control the direction, flow, and speed of the hydraulic oil, thereby achieving the lifting and lowering of the forklift rack A06. During this process, feedback from the central position sensor A52 can be used to achieve precise control.

[0060] Another embodiment of forklift mechanism A control includes a hydraulic loading and unloading transportation system on forklift mechanism A, comprising multiple hydraulic components. A horizontal I-beam support frame A01 is located at the front of the forklift mechanism. A first hydraulic component (which may be a left-side multi-stage hydraulic cylinder A03 and a right-side multi-stage hydraulic cylinder A04) is located at the rear of the I-beam support frame A01. The front end of the first hydraulic component is hinged to the bottom end of the forklift mast A02. A second hydraulic component (which may be a forklift lifting hydraulic cylinder A05) and a cargo box A07 are located at the forklift mast. The second hydraulic component is connected to the cargo box A07 to drive the cargo box A07 to move up and down along the forklift mast A02, thereby adjusting the center of gravity of the forklift mechanism during operation. The output end of the first hydraulic component is connected to the middle of the forklift mast, driving the cargo box to tilt via the forklift mast.

[0061] The forklift mechanism is equipped with sensor components for monitoring the position of the cargo box, the tilt angle of the forklift mast, the force on the excavator's robotic arm, and the load on the cargo box.

[0062] Each hydraulic component has a built-in hydraulic booster cylinder connected to its corresponding hydraulic transformer to form an oil pressure regulating circuit for adjusting the pressure of the hydraulic booster cylinder; the oil pressure regulating circuit is connected to the hydraulic controller.

[0063] The sensor assembly is connected to the hydraulic controller; based on the data from the sensor assembly, the hydraulic controller controls the output force and duration of each hydraulic component through the oil pressure regulation circuit, so as to improve loading and unloading efficiency and reduce the impact on the forklift mechanism and upper frame during the loading and unloading process.

[0064] The hydraulic transformer equipment includes a hydraulic transformer K5, an electromagnetic directional valve K6 for controlling the working state of the hydraulic transformer, and a hydraulic transformer distribution plate angle sensor K14; the hydraulic transformer K5 is connected to the electromagnetic directional valve K6 and the servo proportional valve K12 respectively; a pressure sensor K13 is provided at the servo proportional valve of the hydraulic transformer.

[0065] The hydraulic controller K15 includes a hydraulic transformer control component K4 connected to the hydraulic pump K2. The hydraulic transformer control component controls the rotation angle of the distributor plate of the hydraulic transformer to make the hydraulic transformer output the regulated pressure. The hydraulic transformer control component is also connected to a pressure sensor to monitor the valve port pressure of the servo proportional valve of the hydraulic transformer.

[0066] Each hydraulic power cylinder K9 is connected to the hydraulic transformer via a servo proportional valve K12;

[0067] The A port of the hydraulic transformer K5 is connected to the A port of the electromagnetic reversing valve, the B port of the hydraulic transformer K5 is connected to the oil inlet of the servo proportional valve K12 of the hydraulic booster cylinder, and the T port of the hydraulic transformer K5 is connected to the pump source oil output by the hydraulic pump.

[0068] The operating condition of the hydraulic transformer is determined by the solenoid directional valve. When the solenoid directional valve is de-energized, the hydraulic transformer is working, and the pump source oil output by the hydraulic pump flows into the hydraulic transformer. After being stepped up and down, it is input to the hydraulic booster cylinder through the servo proportional valve. When the solenoid directional valve is energized, the hydraulic transformer is not working, and the pump source oil output by the hydraulic pump is directly input to the hydraulic booster cylinder through the servo proportional valve.

[0069] When the cargo box receives goods directly from the ground, the first hydraulic component drives the forklift mast to flip to a vertical position, and the second hydraulic component lowers the cargo box to the ground so that the cargo box opening facing forward can receive the goods. After receiving the goods, the cargo box is driven to rise again, and the cargo box is placed flat on the forklift mechanism by flipping the forklift mast.

[0070] During the process of receiving goods directly from the ground, if the sensor assembly detects that the load on the cargo box is lower than the light load threshold, the hydraulic controller reduces the oil pressure of the hydraulic booster cylinders of the first and second hydraulic assemblies. By reducing their output force, the lifting and tilting of the cargo box becomes smoother. If the sensor assembly detects that the load on the cargo box is higher than the heavy load threshold, the hydraulic controller first increases the oil pressure of the hydraulic booster cylinder of the second hydraulic assembly so that it has sufficient output force to drive the heavy-load cargo box to rise. Then, it reduces the oil pressure of the hydraulic booster cylinder of the first hydraulic assembly so that the cargo box turns to a flat position at a low speed to avoid excessive impact force on the forklift mechanism from the heavy-load cargo box.

[0071] When the cargo box receives the goods from the excavator's robotic arm, the forklift mast is in a horizontal position so that the cargo box is placed flat on the forklift mechanism with the cargo box opening facing upwards. The hydraulic controller uses the second hydraulic component to drive the cargo box to move horizontally at the forklift mast based on the force on the excavator's robotic arm measured by the sensor assembly. The weight of the cargo box balances the force on the excavator's robotic arm, keeping the forklift mechanism's posture stable.

[0072] When unloading goods from the cargo box that is placed horizontally at the forklift mechanism, first move the cargo box to the bottom of the forklift mast, and then use the vertical tilting of the forklift mast to make the cargo box opening face forward so that the goods can be quickly dumped out.

[0073] During the unloading process, if the sensor assembly detects that the load on the cargo box is higher than the heavy load threshold, the hydraulic controller reduces the oil pressure of the second hydraulic assembly to reduce its output force, thereby reducing the impact force on the forklift mechanism when the cargo box starts and stops as it moves to the bottom of the forklift mast. At the same time, the hydraulic pressure of the first hydraulic assembly is increased to increase its output force, so that it can drive the forklift mast to tilt more smoothly when tilting vertically. If the sensor assembly detects that the load on the cargo box is lower than the light load threshold, the hydraulic controller increases the oil pressure of the hydraulic booster cylinders of the first and second hydraulic assemblies, thereby increasing their output force to make the lifting and tilting of the cargo box faster, thereby improving unloading efficiency.

[0074] The operating conditions of the forklift mechanism include forklift operating conditions, truck operating conditions, and excavator operating conditions;

[0075] When the forklift mechanism is working in excavator mode, the forklift mast is in a horizontal position with the cargo box opening facing upward to receive the excavated material from the excavator's mechanical arm. The second hydraulic component drives the cargo box to move horizontally along the forklift mast A02 away from the excavator's mechanical arm. By changing the position of the cargo box, a counterweight is formed to balance the force exerted on the bucket during the excavation process, ensuring the stability of the forklift body when excavating heavy objects.

[0076] When the forklift mechanism is working in truck mode, the forklift mast is in a horizontal position, the cargo box opening is facing upwards, and the excavator's bucket is facing the cargo box. The second hydraulic component drives the cargo box to move horizontally along the forklift mast A02. By changing the position of the cargo box and the posture of the excavator's mechanical arm, the position of the forklift's center of gravity is adjusted to ensure that the forklift mechanism travels smoothly.

[0077] When the forklift mechanism is in forklift operation mode, the forklift mast is in a vertical position, and the cargo box opening faces the front of the forklift mechanism to facilitate loading the cargo box from the horizontal direction. The second hydraulic component drives the cargo box to rise and fall vertically along the forklift mast A02 to lift the goods received by the cargo box.

[0078] The second hydraulic assembly is detachably connected to the cargo box A07 via the left fork A65 and right fork A66 of the forklift mast.

[0079] The frame 1 of the forklift mechanism is rectangular when viewed from above, and retractable outriggers are provided at its four corners. When the forklift mechanism is working in forklift or excavator mode, the outriggers extend to lift the forklift mechanism until all the tires of the forklift mechanism are off the ground.

[0080] The hydraulic oil for each hydraulic component is supplied by the hydraulic pump of the forklift mechanism, which is driven by the engine of the forklift mechanism. The sensor assembly includes limit switches located at the forklift mast, as well as weighing devices located at the front and bottom of the cargo box.

[0081] The forklift mechanism is driven by a hydraulic motor, which is driven by a third hydraulic component. When the forklift mechanism is in driving condition, the hydraulic controller shuts off the hydraulic oil supply to the first and second hydraulic components through the oil pressure regulation circuit.

[0082] The technical solution of this invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this invention is obviously not limited to these specific embodiments. Without departing from the principles of this invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from these changes or substitutions will all fall within the scope of protection of this invention.

Claims

1. A four-wheel differential travel chassis structure, characterized in that: The vehicle consists of three parts: a frame (1), a wheel system (2), and a suspension (3). The frame (1) is divided into an upper frame (11) and a lower frame (12). The upper surface of the upper frame (11) is used to support and install functional components. On the left and right sides of the front beam (111) and rear beam (112) of the frame (1), there are four outrigger hydraulic cylinders (113). During vehicle transportation, the piston rod of the outrigger hydraulic cylinder (113) does not extend. During engineering operations, the piston rod extends so that the bottom of the piston rod contacts the ground, the overall vehicle height is raised, the tires are lifted off the ground, and the overall vehicle support stability is enhanced. The lower frame (12) is welded to the lower surface of the upper frame (11). The lower frame (12) is used to connect the upper frame (11), the suspension part (3) and the wheel system part (2). The lower frame (12) is constructed by welding the suspension connecting beam (121), the vertical beam (122) and the short cross beam (123). Two vertical beams (122) are vertically welded between two parallel upper and lower suspension connecting beams (121). The two suspension connecting beams (121) and the two vertical beams (122) form a set of vertical components. Multiple short crossbeams (123) are arranged in parallel between the two sets of vertical components. Each suspension connecting beam (121) has spaced lugs on its left and right sides, with perforations on the lugs. A first pin (124) is installed in the perforations of the two lugs, and a first bearing sleeve (125) is fitted on the first pin (124). The upper surface of the upper frame (11) carries a forklift mechanism (A), which includes an I-beam support frame (A01). The front end of the I-beam support frame (A01) is hinged to a forklift mast (A02). The left and right sides of the middle of the forklift mast (A02) are respectively hinged to the front ends of the left multi-stage hydraulic cylinder (A03) and the right multi-stage hydraulic cylinder (A04). The tail end of the pressure cylinder (A04) is hinged to the rear end of the I-beam support frame (A01). The bottom of the forklift mast (A02) is fixedly connected to the tail end of the forklift lifting hydraulic cylinder (A05). The head of the forklift lifting hydraulic cylinder (A05) is fixedly connected to the top of the forklift rack (A06). The front end of the forklift rack (A06) is connected to a loading and unloading box (A07) via a positioning pin (A71). When it is necessary to fix the loading and unloading box (A07) on the forklift rack (A06), it is fixed by the positioning pin (A71). When it is not necessary to fix the loading and unloading box (A07) on the forklift rack (A06), the positioning pin (A71) is removed and the loading and unloading box (A07) is taken off.

2. The four-wheel differential travel chassis structure according to claim 1, characterized in that: The wheel system (2) consists of four components: wheel system support frame (21), hydraulic motor (22), reducer (23) and wheel (24). The wheel system support frame (21) is welded from plate. The wheel system support frame (21) has a second pin (25) installed at each of the four diagonal corners. The second pin is fitted with a second bearing sleeve (26). The hydraulic motor (22), reducer (23) and wheel (24) are connected to the wheel system support frame (21) by bolts. By driving the output shaft of the hydraulic motor (22) to rotate, the reducer (23) and wheel (24) are driven to rotate, providing driving power for the chassis.

3. The four-wheel differential travel chassis structure according to claim 2, characterized in that: The suspension section (3) uses a double wishbone independent suspension. The double wishbone suspension has two A-shaped control arms, upper and lower. The upper control arm is welded together by two mirror-symmetrical connecting rods (31) and a middle support rod (32). One end of the upper control arm is hinged to the upper part of the suspension connecting beam (121), and the other end is hinged to the upper part of the wheel support frame (21). The lower control arm is welded together by two mirror-symmetrical connecting rods (31) and a middle support plate (33). One end of the lower control arm is hinged to the lower part of the suspension connecting beam (121). The other end is hinged to the lower part of the wheel support frame (21). At this time, one end of the double wishbone suspension is hinged to the frame part (1), and the other end can swing up and down relative to the pin shaft around the wheel support frame (21). A shock absorber (4) is installed in the middle of the upper and lower control arms. The upper end of the shock absorber is connected to the short crossbeam (123) and the frame part (1) through the upper ear (41) of the shock absorber, and the lower end is connected to the support plate (33) of the lower control arm through the lower ear (42) of the shock absorber. It plays a buffering role when the wheel (24) moves up and down, ensuring the balance and stability of the chassis.

4. The four-wheel differential travel chassis structure according to claim 3, characterized in that: The forklift mast (A02) includes a forklift mast body (A21). The left and right sides of the middle part of the forklift mast body (A21) are welded to the left first lifting lug assembly (A22) and the right first lifting lug assembly (A23), respectively. The bottom of the forklift mast body (A21) is welded to the left second lifting lug assembly (A24) and the right second lifting lug assembly (A25). The bottom of the forklift mast body (A21) is welded to the bottom support plate (A26). The tail of the forklift lifting hydraulic cylinder (A05) is fixedly connected to the bottom support plate (A26).

5. The four-wheel differential travel chassis structure according to claim 4, characterized in that: The forklift rack (A06) mentioned above includes an outer frame assembly (A61), an inner frame assembly (A62) welded to the inside of the outer frame assembly (A61), an upper load-bearing frame assembly (A63) welded to the top of the inner frame assembly (A62), a connecting rod (A64) connected to the middle of the outer frame assembly (A61), a left fork (A65) and a right fork (A66) slidably connected to the connecting rod (A64), both the left fork (A65) and the right fork (A66) are L-shaped, and their upper parts are slidably connected to the connecting rod (A64), and a roller (A67) connected to the inner frame assembly (A62), the roller (A67) being limited to rolling within the guide rail groove of the forklift mast body (A21).

6. The four-wheel differential travel chassis structure according to claim 5, characterized in that: The aforementioned loadable container (A07) is welded from steel plates and angle steel, and its dimensions are consistent with those of the outer frame assembly (A61). It is fixedly connected by a positioning pin (A71) to ensure that the loadable container (A07) is constrained by the outer frame assembly (A61), the left fork (A65), and the right fork (A66) around it during the movement of the device.

7. The four-wheel differential chassis structure according to claim 6, characterized in that: The left second lifting lug assembly (A24) and the right second lifting lug assembly (A25) are connected to the left and right semi-circular protrusions at the front end of the I-shaped support frame (A01) through the left first rotating pin (A11), the first sliding bearing (A15), the right first rotating pin (A12), and the second sliding bearing (A16), respectively, so as to realize the rotation setting of the forklift mast (A02).

8. The four-wheel differential travel chassis structure according to claim 7, characterized in that: The two ends of the left multi-stage hydraulic cylinder (A03) are rotatably connected to the left first joint bearing (A33), the left second rotating pin (A13), and the left second joint bearing (A34) and the left third rotating pin (A35); the two ends of the right multi-stage hydraulic cylinder (A04) are rotatably connected to the right first joint bearing (A43), the right second rotating pin (A14), the right second joint bearing (A44), and the right third rotating pin (A45), thus realizing the rotational setting of the multi-stage hydraulic cylinders on both sides.

9. The working method of the four-wheel differential walking chassis structure according to claim 8, characterized in that: Simultaneously, the left multi-stage hydraulic cylinder (A03) and the right multi-stage hydraulic cylinder (A04) can be activated to shorten the length of the hydraulic cylinders. The left multi-stage hydraulic cylinder (A03) rotates around the left first joint bearing (A33) and the left second rotating pin (A13), while the right multi-stage hydraulic cylinder (A04) rotates around the right first joint bearing (A43) and the right second rotating pin (A14). This causes the forklift mast (A02) to rotate around the left first rotating pin (A11), the first sliding bearing (A15), the right first rotating pin (A12), and the second sliding bearing (A16), adjusting the center of gravity of the forklifted goods so that the center of gravity is biased towards the center of the device. This ensures the reliability and stability of the device in loading and unloading goods. In forklift mode, the device uses the forklift function to load the loadable box (A07). The left-side multi-stage hydraulic cylinder (A03) and right-side multi-stage hydraulic cylinder (A04) are activated, causing the forklift mast (A02), forklift lifting hydraulic cylinder (A05), forklift rack (A06), and loadable box (A07) to rotate around the left-side rotating pin (A11) and right-side rotating pin (A12). Precise control of the forklift section's rotation is achieved through the combined action of the left-side proportional valve (A31), left-side position sensor (A32), right-side proportional valve (A41), and right-side position sensor (A42), resulting in a 90-degree rotation of the aforementioned structure, transforming the device from a vertical to a horizontal state. A positioning pin (A71) is installed at the connection between the outer frame assembly (A61) and the head of the loadable box (A07), enabling the switching between forklift and freight modes. In freight mode, the device activates the forklift lifting hydraulic cylinder (A05), causing the forklift rack (A06), the loadable and unloadable box (A07), and the goods to move to the left. This shifts the center of gravity of the device and the goods to the left, bringing the center of gravity closer to the center and ensuring the reliability and stability of the device in transporting goods.

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