Engineering truck

Abstract

The invention provides an engineering vehicle. The engineering vehicle comprises a chassis, the chassis comprises a frame, and a plurality of locking devices and a hydraulic system are arranged on the frame; an auxiliary frame is arranged on the upper assembly, locking hasps are arranged on the outer side of the auxiliary frame, the locking hasps and the locking devices are arranged in a one-to-one correspondence mode, the chassis and the upper assembly are detachably connected through the locking devices and the locking hasps, and the upper assembly comprises at least one of a dump truck upper assembly, a concrete mixer truck upper assembly and a crane truck upper assembly; wherein the hydraulic system is provided with an assembling position enabling the upper part to be located above the chassis and enabling the auxiliary frame to be attached to the frame, and the hydraulic system is provided with a separating position enabling the upper part to be separated from the chassis. The problems that in the prior art, different upper assemblies cannot be rapidly replaced on an engineering vehicle chassis, and reliable positioning and locking of the upper assemblies and the chassis cannot be achieved are solved.

Description

engineering vehicle Technical Field

[0001] This invention relates to the field of quick-change systems for engineering vehicles, and more specifically, to an engineering vehicle. Background Technology

[0002] Currently, the engineering vehicle industry generally adopts an integrated chassis and superstructure design. Specialized vehicles with different functions, such as dump trucks, concrete mixer trucks, truck-mounted cranes, and garbage trucks, all need to be equipped with dedicated chassis. Each superstructure and chassis has a fixed matching relationship and cannot be quickly interchanged.

[0003] Although systems exist in the field of ordinary van transport vehicles that enable the exchange of cargo boxes through airbag lifting or mechanical hoisting, such technologies are only suitable for lightly loaded vans that do not require hydraulic power. They cannot meet the comprehensive requirements of engineering vehicle superstructures for high load-bearing capacity, high dynamic hydraulic power output, precise positioning, and reliable locking.

[0004] No effective solution has yet been proposed to address the above issues. Summary of the Invention

[0005] The main objective of this invention is to provide an engineering vehicle that solves the problems in the prior art where the chassis of an engineering vehicle cannot be quickly replaced with different superstructures and the superstructure cannot be reliably positioned and locked to the chassis.

[0006] To achieve the above objectives, according to one aspect of the present invention, an engineering vehicle is provided, comprising: a chassis, the chassis including a frame, the frame being provided with a plurality of locking devices and a hydraulic system; a superstructure, the superstructure being provided with a subframe, the outer side of the subframe being provided with locking latches, the locking latches being provided in a one-to-one correspondence with the locking devices, the chassis and the superstructure being detachably connected via locking devices and locking latches, wherein the superstructure includes at least one of: a dump truck superstructure, a concrete mixer truck superstructure, and a crane truck superstructure; wherein the hydraulic system has an assembly position for positioning the superstructure above the chassis and the subframe being in contact with the frame, and a separation position for separating the superstructure from the chassis.

[0007] Furthermore, the chassis includes: a power unit, wherein multiple power units are provided, each power unit being located on the outside of the frame; and a positioning groove, wherein multiple positioning grooves are provided, each positioning groove being located on the outside of the frame, the positioning grooves being spaced apart along the length direction of the frame, and at least one positioning groove being located on one side of the locking device.

[0008] Furthermore, the upper structure includes: upper structure legs, four upper structure legs are provided, the upper structure legs are located on the outside of the subframe, two upper structure legs are provided on each side of the subframe, the upper structure legs on both sides are symmetrically arranged, the upper structure legs on the same side are spaced apart along the length direction of the subframe, and the upper structure legs are detachably connected to the subframe; a guide device, the guide device is located on the outside of the subframe, and part of the guide device protrudes from the lower edge of the subframe; a bracket, the two ends of the bracket are respectively connected to the upper structure legs on both sides, and the bracket is provided with a limiting groove.

[0009] Furthermore, the locking device includes a U-bolt latch, which is locked to the locking latch when the upper part is in the assembly position, and the length of the U-bolt latch is 10~20mm.

[0010] Furthermore, the power unit is a hydraulic cylinder, and the end of the piston rod of the hydraulic cylinder is provided with a conical push head. When the upper part is in the assembly position, the protruding part of the guide device is located in the positioning groove, the conical push head is located in the limiting groove, and the gap between the conical push head and the limiting groove is set.

[0011] Furthermore, the hydraulic system includes: an electromagnetic clutch, which is located between the PTO output shaft of the chassis and the input shaft of the variable oil pump. The electromagnetic clutch connects or disconnects the power transmission path according to the type of the superstructure. The output end of the variable oil pump is connected to the hydraulic oil tank, the input end of the multi-way valve group, and the high-pressure port of the superstructure hydraulic system power system through a three-way connector. The output end of the multi-way valve group is connected to the power unit and the hydraulic oil tank.

[0012] Furthermore, the multi-way valve assembly is a three-position four-way electro-hydraulic directional valve assembly. The outlet of the multi-way valve assembly is connected to each power unit through a high-pressure oil pipe. A synchronous flow divider valve is installed on the high-pressure oil pipe. After passing through the synchronous flow divider valve, the high-pressure oil pipe generates a first oil circuit and a second oil circuit. The first oil circuit is used to supply oil to the power unit located at the front of the vehicle, and the second oil circuit is used to supply oil to the power unit located at the rear of the vehicle. Each power unit is connected to the inlet of the multi-way valve assembly through a first return oil pipe. A two-way throttle valve is installed at the same position on both the first return oil pipe and the high-pressure oil pipe.

[0013] Furthermore, the multi-way valve group includes multiple individual valve bodies, each of which is a three-position control valve. The three-position control valve has three states: advance, stop, and reverse return.

[0014] Furthermore, the multi-way valve group has a first control circuit and a second control circuit. The first control circuit is used to control the lifting and lowering actions of multiple power units, and the second control circuit is used to control the hydraulic power unit of the upper structure.

[0015] Furthermore, each power unit is equipped with an explosion-proof valve.

[0016] By applying the technical solution of this invention, the engineering vehicle achieves precise positioning and reliable connection between the superstructure and the chassis by installing multiple locking devices and a hydraulic system on the chassis frame, and by installing corresponding locking buckles on the outer side of the subframe of the superstructure, each matching one of the locking devices. The hydraulic system can switch between two distinct positions: one is the assembly position, which allows the superstructure to be precisely lowered above the chassis, with the subframe and the frame fully fitted, ensuring that the two are highly consistent in spatial posture and structural mating surface; the other is the separation position, which allows the hydraulic system to drive the superstructure to be lifted as a whole and detached from the chassis, eliminating mechanical interference. The same chassis can be adapted to various superstructures such as dump trucks, mixers, and cranes, achieving "one vehicle for multiple uses" and significantly improving chassis utilization. Especially in seasonal shutdown scenarios (such as when mixer trucks are not used in winter), it can be quickly converted to dump truck function, reducing operating costs. This application solves the problem in the prior art that engineering vehicle chassis cannot quickly change different superstructures and cannot achieve reliable positioning and locking between the superstructure and the chassis. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 shows a structural schematic diagram of a first embodiment of the engineering vehicle according to the present invention;

[0019] Figure 2 shows a structural schematic diagram of a second embodiment of the engineering vehicle according to the present invention;

[0020] Figure 3 shows an assembly schematic diagram of an optional engineering vehicle according to the present invention;

[0021] Figure 4 shows an enlarged schematic diagram of point A in Figure 3;

[0022] Figure 5 shows an assembly schematic diagram of an optional engineering vehicle according to the present invention;

[0023] Figure 6 shows an enlarged schematic diagram of point B in Figure 5;

[0024] Figure 7 shows an assembly schematic diagram of an embodiment of an optional engineering vehicle according to the present invention;

[0025] Figure 8 shows an enlarged schematic diagram of point C in Figure 7;

[0026] Figure 9 shows a structural schematic diagram of an embodiment of the locking device according to the present invention;

[0027] Figure 10 shows a side view of an embodiment of the locking device according to the present invention;

[0028] Figure 11 shows a schematic diagram of an embodiment of the hydraulic system according to the present invention;

[0029] Figure 12 shows a schematic diagram of an embodiment of the hydraulic system according to the present invention.

[0030] The above figures include the following reference numerals:

[0031] 1. Chassis; 100. Frame; 11. Locking device; 12. Power unit; 13. Positioning groove;

[0032] 2. Upper structure; 200. Subframe; 21. Locking buckle; 22. Upper structure support leg; 23. Guide device; 24. Bracket; 25. Limiting groove;

[0033] 31. Electromagnetic clutch; 32. Variable displacement pump; 33. Inlet pipe; 34. Outlet pipe; 35. Quick-connect pipe; 36. Valve body; 37. Multi-way valve assembly; 38. Hydraulic oil tank; 40. First oil circuit; 41. Two-way throttle valve; 42. High-pressure oil pipe; 43. Synchronous flow divider valve; 44. First return oil pipe; 45. Second oil circuit; 46. Explosion-proof valve; 47. Solenoid valve; 48. Conical pusher; 50. Return oil throttle valve; 51. Return oil line; 52. T-junction;

[0034] 70. Hydraulic power unit. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that 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.

[0037] 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 terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0038] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0039] Research on exchange box systems in the domestic and international industries reveals that most exchange systems utilize airbags to lift the truck body or superstructure, and are primarily used for exchanging cargo box bodies, with no exchanging systems available for engineering vehicles. The patent "Multi-Applicable Demountable Truck Body," while featuring a hydraulic system for lifting and supporting the truck body and providing hydraulic power output to bodies with hydraulic outriggers, still falls under the category of exchange systems applicable to truck bodies. It lacks a description and claims of power output technology for engineering vehicle superstructures. In other words, there is no domestic exchanging system specifically for hydraulically powered superstructures required for engineering vehicles such as dump trucks, mixer trucks, truck-mounted cranes, and large-capacity garbage trucks, and no solutions exist for post-exchange superstructure positioning and securing on the chassis.

[0040] Referring to Figures 1 to 12, an engineering vehicle is provided according to a specific embodiment of this application.

[0041] Specifically, the engineering vehicle includes: a chassis 1, which includes a frame 100, on which multiple locking devices 11 and a hydraulic system are provided; and a superstructure 2, on which a subframe 200 is provided, with locking buckles 21 on the outer side of the subframe 200. The locking buckles 21 are correspondingly arranged with the locking devices 11. The chassis 1 and the superstructure 2 are detachably connected through the locking devices 11 and the locking buckles 21. The superstructure 2 includes at least one of the following: a dump truck superstructure, a concrete mixer truck superstructure, and a crane truck superstructure. The hydraulic system has an assembly position that positions the superstructure 2 above the chassis 1 and the subframe 200 in contact with the frame 100, and a separation position that separates the superstructure 2 from the chassis 1.

[0042] By applying the technical solution of this invention, the engineering vehicle achieves precise positioning and reliable connection between the superstructure 2 and the chassis 1 by setting multiple locking devices 11 and a hydraulic system on the frame 100 of the chassis 1, and by setting corresponding locking buckles on the outer side of the subframe of the superstructure 2 to match the locking devices one by one. The hydraulic system can switch between two distinct positions: one is the assembly position, which allows the superstructure to be precisely lowered above the chassis, with the subframe 200 and the frame 100 completely in contact, ensuring that the two are highly consistent in spatial posture and structural docking surface; the other is the separation position, which allows the hydraulic system to drive the superstructure to be lifted as a whole and detached from the chassis, eliminating mechanical interference. The same chassis can be adapted to various superstructures such as dump trucks, mixers, and cranes, realizing "one vehicle for multiple uses" and greatly improving the utilization rate of the chassis. Especially in seasonal shutdown scenarios (such as when mixer trucks are not used in winter), it can be quickly converted to dump truck function, reducing operating costs. This application solves the problem in the prior art that engineering vehicle chassis cannot quickly change different superstructures and cannot achieve reliable positioning and locking between the superstructure and the chassis.

[0043] Specifically, the chassis 1 includes: a power unit 12, which is provided in multiple ways, and each power unit 12 is located on the outside of the frame 100; a positioning groove 13, which is provided in multiple ways, and each positioning groove 13 is located on the outside of the frame 100. The positioning grooves 13 are spaced apart along the length direction of the frame 100, and at least one positioning groove 13 is located on one side of the locking device 11.

[0044] Each power unit is an independently mounted mechanical actuator on the outside of the chassis, used to provide lifting or support during the superstructure loading and unloading process. Their number and distribution correspond to the load-bearing support points of the superstructure subframe. Each power unit is rigidly fixed to the outer side of the chassis longitudinal beams, arranged at equal intervals along the longitudinal direction of the chassis to form a symmetrical layout, ensuring uniform stress distribution when bearing the weight of the superstructure and avoiding localized stress concentration. The power units do not participate in vehicle operation when not in use, only activating during superstructure loading and unloading. Their installation positions avoid the main load-bearing stress areas of the chassis to minimize the impact on the chassis structural strength.

[0045] The locking device 11 is a mechanical locking fastener located on the outer edge of the frame. Its function is to permanently or semi-permanently fix the subframe 200 of the superstructure to the frame 100 through mechanical fastening after the superstructure is lifted to the assembly height by the power unit. The locking device is a structural unit independent of the positioning slot and the power unit. Its mounting plane is higher than or parallel to the plane where the positioning slot is located. The two do not interfere with each other in space and are complementary in function: the positioning slot is responsible for precise positioning in the horizontal direction, and the locking device is responsible for mechanical locking in the vertical direction. The relative positional relationship between the positioning slot and the locking device is a fixed design that does not change with the type of superstructure. This ensures that no matter what type of superstructure is replaced, the alignment reference and locking point with the frame remain consistent, achieving standardization and multi-purpose adaptability of the chassis. All power units, positioning slots, and locking devices are directly integrated into the frame body without relying on external lifting or auxiliary equipment. Their arrangement forms the basic load-bearing and positioning platform for the chassis replacement function, providing structural support for the autonomous loading, unloading, and rapid interchange of superstructures.

[0046] In this embodiment, there are 4 power units 12, which are divided into two groups. Each group has two power units 12 spaced apart along the width of the vehicle. One group is located at the end of the chassis frame near the cab, and the other group is located at the end of the chassis away from the cab.

[0047] Specifically, the upper structure 2 includes: upper structure support legs 22, four upper structure support legs 22 are provided, the upper structure support legs 22 are located on the outside of the sub-frame 200, two upper structure support legs 22 are provided on each side of the sub-frame 200, the upper structure support legs 22 on both sides are symmetrically arranged, the upper structure support legs 22 on the same side are spaced apart along the length direction of the sub-frame 200, and the upper structure support legs 22 are detachably connected to the sub-frame 200; guide device 23, the guide device 23 is located on the outside of the sub-frame 200, part of the guide device 23 protrudes from the lower edge of the sub-frame 200; bracket 24, the two ends of the bracket 24 are respectively connected to the upper structure support legs 22 on both sides, and the bracket 24 is provided with limiting grooves 25.

[0048] Specifically, in this embodiment, the superstructure 2 is provided with four superstructure support legs 22, which are arranged on the left and right sides of the subframe 200, with two legs on each side, distributed longitudinally along the subframe 200 to form a symmetrical four-point support pattern. Each superstructure support leg 22 is an independent and detachable mechanical support component. Its top end is detachably connected to the mounting seat on the outside of the subframe 200 through a bolt group or pin structure, which facilitates quick disassembly or installation when changing different superstructures, realizing modular assembly of the support leg and the subframe. The support leg body is a rigid metal structure, which is telescopic or fixed in shape. It is provided with a wide foot at the bottom, which is used to stand independently on the ground after the superstructure is detached from the chassis, bear the weight of the superstructure and the working load, and ensure stability in non-transportation or non-assembly state.

[0049] Part of the guide device 23 protrudes from the lower edge of the subframe 200. The guide device 23 is an integrally formed metal structural component, the main body of which is fixed to the outer wall of the subframe 200, and its lower end extends vertically and protrudes from the bottom surface of the subframe, forming a protrusion higher than the lower edge of the subframe. This protrusion is a straight or beveled strip structure, and its length direction is consistent with the longitudinal direction of the subframe. It is used to provide sliding guidance with the chassis positioning structure during the assembly of the superstructure and the chassis. Its protrusion height is sufficient to make contact with the corresponding structure of the chassis first during the descent of the superstructure, guiding the subframe to complete horizontal alignment and avoiding deviation.

[0050] Between the two upper support legs 22, a connecting bracket 24 is provided. This bracket is a rigid beam that runs horizontally through the bottom of the subframe 200. Its two ends are fixedly connected to the upper support legs 22 on the left and right sides, respectively, forming a stable spatial truss structure. This enhances the overall rigidity of the support legs and prevents bending or torsion due to uneven stress during load-bearing. A limiting groove 25 is provided in the middle area of ​​the bracket 24. This limiting groove 25 is a recessed structure with its opening facing downwards. The groove extends longitudinally along the subframe, and its width and depth are designed to accommodate partial components of the chassis support structure.

[0051] The edge of the limiting groove 25 has no sharp corners and is rounded to reduce stress concentration. The groove contains no other functional structures or accessories; it serves solely as a passageway. Its position corresponds to the arrangement of the upper structure's outriggers, ensuring that the limiting groove remains aligned with the subframe centerline even after the outriggers are retracted or removed, and does not shift due to changes in outrigger position. The combined structure of the bracket 24 and the limiting groove 25 does not participate in load-bearing, positioning, or direct contact with the chassis. It only serves to facilitate the passage of the lifting mechanism during the replacement process and is a functional clearance structure in the upper structure specifically designed to accommodate chassis movements.

[0052] Optionally, in this embodiment, each positioning groove 13 is a partially formed groove structure on the outer side of the frame 100, with its opening facing upwards and a rectangular or V-shaped cross-section. Its depth and width are designed to adapt to the guide device 23 of the subframe of the superstructure, used to guide and limit the horizontal displacement of the superstructure. The positioning grooves 13 are arranged sequentially at intervals along the longitudinal direction of the frame, with no fewer than two, located at the front and rear ends of the frame 100 respectively, ensuring stable alignment of the superstructure in the longitudinal length direction.

[0053] Specifically, the locking device 11 includes a U-shaped bolt latch. When the upper part 2 is in the assembly position, the U-shaped bolt latch and the locking latch 21 are locked together. The length of the U-shaped bolt latch is 10~20mm.

[0054] The U-bolt latch and locking latch 21 work together to achieve mechanical locking between the superstructure 2 and the chassis 1. The length of the U-bolt latch is 10 to 20 mm, which is the effective clamping length of the bearing end. This ensures that it can cross and stably press against the designated overlapping area of ​​the longitudinal beam of the superstructure subframe when locked. This avoids the inability to form an effective constraint due to being too short, and also prevents interference or assembly difficulties due to being too long.

[0055] Optionally, in this embodiment, the locking latch 21 is welded or riveted to the subframe 200. Its installation position is precisely aligned with the movement trajectory of the U-bolt latch on the chassis frame, ensuring that after the superstructure descends to the assembly position, the U-bolt latch can fall vertically and automatically engage in the locking latch slot. When the superstructure is in the assembly position, the U-bolt latch falls under gravity or manual operation, and its bent section engages in the slot of the locking latch. The bolt arms at both ends of the U-bolt pass through the side wall holes of the locking latch. Then, a preload is applied by the handle or quick-release nut, so that the U-bolt latch forms a lateral clamping force on the longitudinal beam of the subframe, tightly pressing the superstructure subframe and the chassis frame together, eliminating the gap and relative displacement tendency between them.

[0056] In another specific embodiment, the locking device is a locking device structure of hinge bolts combined with locating pins. The locking device includes two sets of hinge bolt locking units symmetrically arranged on both sides of the chassis frame, and two sets of locating pin holes and locating pin assemblies located at both ends of the longitudinal direction of the upper subframe. Each set of hinge bolt locking units consists of the following components: a hinge seat fixedly installed on the web of the chassis frame, which is integrally formed from cast steel and has a rotating shaft hole; a lever bolt arm connected to the hinge seat through a rotating shaft, one end of which is a handle and the other end is a threaded screw; and a matching threaded locking plate fixedly installed on the outside of the longitudinal beam of the upper subframe, which has a threaded through hole that matches the thread of the screw, and the hole opening has a tapered guide chamfer. Once the subframe is fitted to the chassis frame via the aforementioned hydraulic lifting system and precisely positioned front-to-back and side-to-side by the V-shaped positioning groove and positioning guide device, the operator manually operates the bolt arm handle to rotate the bolt along the hinge axis to a horizontal position, aligning it with the threaded locking plate on the subframe. Then, the handle is rotated to screw the bolt into the threaded locking plate until the bolt end is tightly fitted against the inner wall of the locking plate. Under leverage, the bolt arm applies a downward clamping force to the subframe, ensuring no gaps or looseness between the subframe and the chassis frame. To prevent accidental loosening of the bolt during driving vibrations, a mechanical anti-loosening clip is installed at the end of the bolt. This clip is a manually movable elastic retaining ring. When the bolt is fully tightened, the clip engages in the limiting groove at the bottom of the bolt arm, achieving mechanical self-locking. Meanwhile, to enhance positioning accuracy and torsional rigidity, this embodiment includes a tapered locating pin at both the front and rear ends of the superstructure subframe. These pins are made of hardened alloy steel, with a diameter of Φ25mm±0.05mm, a taper of 1:50, and a polished surface with a roughness Ra≤0.8μm. Correspondingly, the chassis frame has tapered locating pin holes at both the front and rear ends that mate with the locating pins. The hole diameter is slightly smaller than the large end diameter of the locating pin, forming an interference fit structure with a depth of 40mm and a guide bevel at the opening. During the superstructure's descent to the engagement position, the locating pin automatically inserts along the guide bevel of the pin hole. When the superstructure subframe is fully in place, the locating pin and pin hole achieve a triple constraint of interference fit, axial limiting, and circumferential torsional resistance. At this point, the locating pin not only limits the longitudinal and lateral displacement of the superstructure but also effectively resists torsional loads generated by bumps and turns during vehicle operation, preventing relative rotation or slippage of the superstructure. The disassembly process of the locking device is the reverse of the installation process: first, manually move the anti-loosening buckle and rotate the handle counterclockwise to make the screw disengage from the threaded locking plate; then manually pull out the positioning pin to disconnect the mechanical connection between the upper structure and the chassis; then, control the hydraulic cylinder through the multi-way valve to lift the conical push head to complete the separation of the upper structure.

[0057] Specifically, the power unit 12 is a hydraulic cylinder, and the end of the piston rod of the hydraulic cylinder is provided with a conical push head 48. When the upper device 2 is in the assembly position, the protruding part of the guide device 23 is located in the positioning groove 13, the conical push head is located in the limiting groove 25, and the conical push head 48 is separated from the limiting groove 25.

[0058] Specifically, the power unit 12 is a hydraulic cylinder, with its cylinder body fixed to the outside of the chassis frame. The piston rod extends and retracts vertically, and a conical pusher 48 is fixedly connected to the end of the piston rod. The conical pusher 48 is a single machined metal part with a conical curved surface on its outer surface. The cone angle is 15° to 25°, and the conical surface is precision ground and surface hardened, giving it high hardness and low friction characteristics. It is used to achieve axial alignment and radial constraint with the mating structure on the upper subframe. When the upper body 2 moves to the assembly position, the hydraulic cylinder piston rod extends upward, causing the conical pusher 48 to insert into the limiting groove 25 at the lower part of the upper subframe. At this time, the limiting groove 25 is a sleeve-like structure with a conical inner cavity. Its inner wall forms a tight conical surface fit with the outer conical surface of the conical pusher 48, achieving radial self-centering and axial load-bearing, ensuring that the upper body is stably supported in the vertical direction without deviation.

[0059] In this assembled state, the guide device 23 of the upper body 2 protrudes downward along the outer side of the subframe. The protruding part is a strip-shaped rigid guide body. Its outer contour matches the shape of the positioning groove 13 on the outer side of the chassis frame. When the upper body is lowered to the preset height, the protruding part of the guide device 23 slides into the positioning groove 13, thereby limiting and pre-aligning the position of the upper body in the longitudinal and transverse directions, and preventing the upper body from shifting or rotating on the horizontal plane.

[0060] At this point, the conical pusher 48 contacts and maintains a radial gap of 5mm to 10mm with the limiting groove 25. This gap is reserved for assembly tolerances, ensuring that the conical pusher 48 can smoothly enter the limiting groove 25 to complete automatic centering, while avoiding jamming due to thermal expansion and contraction or manufacturing errors. Simultaneously, the gap allows the conical surface to maintain its elastic fine-tuning capability after bearing load, improving the fault tolerance and operational stability of the assembly process. This gap is not sealed and does not transmit hydraulic pressure; it is only a structural fit gap and does not participate in sealing or pressure transmission. After the entire structure is assembled, the hydraulic cylinder piston rod remains stationary. The conical pusher 48 and the conical surface of the limiting groove 25 cooperate to bear the vertical load of the superstructure, while the guide device 23 and the positioning groove 13 work together to bear the horizontal constraint. Together, they constitute a dual positioning system between the superstructure and the chassis.

[0061] Specifically, as shown in Figure 11, the hydraulic system includes: an electromagnetic clutch 31, which is located between the PTO output shaft of the chassis 1 and the input shaft of the variable oil pump 32. The electromagnetic clutch 31 connects or disconnects the power transmission path through the type of the upper device 2; the output end of the variable oil pump 32 is connected to the hydraulic oil tank 38, the input end of the multi-way valve group 37 and the high-pressure port of the hydraulic system power system of the upper device 2 through a three-way connector; the output end of the multi-way valve group 37 is connected to the power unit 12 and the hydraulic oil tank 38.

[0062] PTO refers to Power Take-Off, a mechanical interface device installed in the chassis transmission system of an engineering vehicle. It is used to extract engine power from the chassis's gearbox or transfer case and transmit it to external auxiliary working devices. The PTO is a standardized rotary output shaft structure. Its input end meshes with the output gear or intermediate shaft of the chassis gearbox via splines or gears, while its output end connects to external equipment (such as the electromagnetic clutch 31 in this application) via a flange or universal joint. When the driver operates the PTO clutch control switch, the power transmission path from the engine to the PTO shaft can be connected or disconnected, achieving a function switch between "no operation while driving" and "operation while stopped."

[0063] The electromagnetic clutch 31 is an electronically controlled dry friction clutch mechanism. Its driving plate is directly connected to the PTO output shaft of the chassis 1 via a spline, while the driven plate is rigidly coupled to the input shaft of the variable oil pump 32. Both are coaxially mounted on the outer side of the chassis frame and do not interfere with the driving transmission system. When the electromagnetic clutch 31 is not energized, it is in a disengaged state, cutting off the power transmission path between the PTO output shaft and the variable oil pump 32. When the upper structure 2 is a type that requires continuous power output (such as a concrete mixing tank), the control system triggers the electromagnetic clutch 31 to be energized and engaged, so that the PTO power is completely transmitted to the variable oil pump 32 through the electromagnetic clutch 31. When the upper structure 2 is a type that only requires intermittent power (such as a dump truck or a truck-mounted crane), the electromagnetic clutch 31 is de-energized and disengaged, blocking the power transmission and keeping the variable oil pump 32 in an idle and stopped state, avoiding energy loss and oil temperature rise caused by no-load circulation of the hydraulic system.

[0064] The variable displacement pump 32 is an axial piston or gear-type variable displacement pump. Its input end is coaxially connected to the driven end of the electromagnetic clutch 31, and its output end is connected to the main port of a tee connector through a high-pressure oil passage that is integrally formed or flanged. The tee connector is a three-way tubular metal component, and its three ports are respectively connected as follows: one end leads to the hydraulic oil tank 38, forming a return oil bypass branch; one end leads to the input end of the multi-way valve group 37 through the oil outlet pipe 34, serving as the main power output channel; and the other end is directly connected to the high-pressure oil inlet of the hydraulic power system of the upper structure 2 through the quick-connect pipe 35, forming an independent upper structure oil supply path. The internal flow channel of the tee connector is polished and has no shut-off structure, ensuring that the oil is diverted without pressure drop loss under different operating conditions. Its structure only serves as a distribution point and does not have a check valve or pressure regulating valve.

[0065] The hydraulic oil tank 38 is a closed oil storage container fixed to the bottom of the chassis frame. It has a vent and filter at the top, an oil drain port at the bottom, and is connected to the port of the variable displacement pump 32 via an inlet pipe 33. The tank volume meets the oil suction requirements of the variable displacement pump 32 under maximum flow conditions, and the internal oil level is maintained above the lowest suction port to ensure the pump is always submerged in the suction state. The hydraulic oil tank 38 is connected to the return oil outlet of the multi-way valve group 37 via a return oil line 51. A return oil throttle valve 50 is installed on the return oil line 51. The other port of the return oil throttle valve 50 is connected to the return oil port on the upper structure 2, forming a redundant return oil path for the system. This ensures that the oil can smoothly return to the tank under different control modes, avoiding cavitation and oil temperature buildup.

[0066] In this embodiment, the core control logic of the electromagnetic clutch 31 intelligently determines and automatically responds based on the operating characteristics of the mounted superstructure 2. When the superstructure 2 is a concrete mixing tank, its operation requires the mixing drum to rotate continuously at a low speed to maintain the uniformity of the concrete; at the same time, high-pressure cleaning of the inner wall of the tank is required after the operation, which also requires a long-term, uninterrupted power supply from the hydraulic system. At this time, the control system determines that it is a "continuous power demand type superstructure" and automatically connects the power supply to the electromagnetic clutch 31 to keep it in a constant engagement state. The variable oil pump 32 runs continuously to provide uninterrupted hydraulic power to the reducer drive system of the mixing tank, ensuring that the mixing and cleaning process is smooth and without interruption, and avoiding concrete segregation or incomplete cleaning due to power interruption.

[0067] In another specific embodiment, when the superstructure 2 is a dump truck, a truck-mounted crane, or a hooklift truck, its operating characteristics are intermittent and discontinuous: the dump truck only requires hydraulic power during the moment of lifting and unloading; the truck-mounted crane only requires hydraulic drive during lifting, luffing, and slewing operations; and the hooklift truck only requires brief power output when grabbing, towing, and dumping garbage. Under these operating conditions, if the hydraulic gear pump runs continuously, a large amount of hydraulic oil will circulate idly within the system, causing not only unnecessary energy loss, abnormally high oil temperature, and accelerated fatigue of the pump body and pipelines, but also posing a safety risk of accidental hydraulic cylinder operation due to misoperation or control system failure. Therefore, when the control system identifies the superstructure type as "intermittent operation type," it only briefly engages the electromagnetic clutch 31 to start the variable oil pump 32 at the moment it receives the operation command (such as pressing the lifting button or the boom start signal); after the operation is completed, the control signal is removed, the electromagnetic clutch 31 is immediately de-energized and disengaged, the power chain is completely cut off, the variable oil pump 32 stops rotating, and the system returns to a zero-power standby state.

[0068] This control mechanism achieves a "precise match" between power supply and operational needs. While meeting the rigid requirement of "continuous power" for concrete mixing tanks, it completely avoids ineffective energy consumption and potential loss of control risks during non-operational periods for the dump truck, crane, and boom lift. Compared to the traditional crude hydraulic system of "constantly running engine, PTO, and pump," this solution achieves an energy-saving power architecture of "power supply on demand and shutdown upon power failure" through the intelligent on / off switching of the electromagnetic clutch. This significantly reduces fuel consumption, reduces hydraulic system heat generation, extends component life, and improves the overall vehicle's operational safety and intelligence. This structure is the core technical means to achieve the function of "one chassis adapting to multiple superstructures" and is also one of the key innovations that distinguishes this invention from existing van-type exchange systems.

[0069] The multi-way valve group 37 is a single-valve block integrated three-position four-way directional valve group. Its input end is connected to the main output end of the three-way connector, receiving high-pressure oil from the variable oil pump 32. Its output end is divided into at least two independent control oil circuits, which are respectively connected to the inlet and return oil ports of the power unit 12 to form a closed-loop hydraulic circuit, realizing the extension and retraction control of the power unit 12. Its return oil outlet is connected to the hydraulic oil tank 38 to form an oil return channel. When the multi-way valve group 37 is in the neutral position, both the input end and the output end are connected to the return oil port, and the system is in an unloaded state. When the operating handle is deflected, the valve core switches the connection path, causing the high-pressure oil to flow into the corresponding chamber of the power unit 12 in a directional manner, driving its action. After the action is completed, the return oil flows back to the hydraulic oil tank 38 through the valve body. The multi-way valve group 37 does not have pressure compensation or flow control. It only serves as a basic directional actuator. Its control logic is triggered by external manual or electronic control signals and does not participate in the start-up and shutdown control of the power source.

[0070] Specifically, the multi-way valve group 37 is a three-position four-way electro-hydraulic directional valve group. The outlet of the multi-way valve group 37 is connected to each power unit 12 through a high-pressure oil pipe 42. A synchronous flow divider valve 43 is provided on the high-pressure oil pipe 42. After passing through the synchronous flow divider valve 43, the high-pressure oil pipe 42 generates a first oil circuit 40 and a second oil circuit 45. The first oil circuit 40 is used to supply oil to the power unit 12 located at the front of the vehicle, and the second oil circuit 45 is used to supply oil to the power unit 12 located at the rear of the vehicle. Each power unit 12 is connected to the inlet of the multi-way valve group 37 through a first return oil pipe 44. A two-way throttle valve 41 is provided at the same position on both the first return oil pipe 44 and the high-pressure oil pipe 42.

[0071] Optionally, the first oil passage 40, the second oil passage 45 and the first return oil pipe 44 are each equipped with a tee 52 to facilitate simultaneous connection with the power unit 12 located on both sides of the vehicle frame through the aforementioned pipes.

[0072] The high-pressure oil pipe 42 is a pressure-bearing seamless steel pipe or a flexible high-pressure rubber composite pipe. Its main body extends from the outlet of the multi-way valve group 37, is laid longitudinally along the chassis frame, and connects to the synchronous flow divider valve 43 at the middle section of the vehicle. The synchronous flow divider valve 43 is a gear-type mechanical flow distributor. Its input end is connected to the high-pressure oil pipe 42, and its output end is divided into two independent channels: the first oil line 40 and the second oil line 45. The two oil lines are symmetrical in structure, have the same inner diameter, equal length, and matched bending radius to ensure balanced flow resistance during the flow division process. The synchronous flow divider valve 43 achieves forced equal distribution of flow through a pair of precisely meshing gear cavities. Regardless of system pressure fluctuations or load differences, it ensures that the oil flow output from the first oil line 40 and the second oil line 45 is equal, thereby ensuring that the two power units 12 located at the front and rear of the vehicle operate synchronously and avoiding tilting, jamming, or force imbalance of the superstructure due to uneven oil supply.

[0073] The first oil circuit 40 is an independent high-pressure oil delivery channel. It starts at the front outlet of the synchronizing flow divider valve 43, extends longitudinally along the left or right side of the chassis, and connects directly to the oil inlet of the power unit 12 located at the front of the vehicle, providing high-pressure power oil to the front-end actuators. The second oil circuit 45 is a symmetrical independent channel. It starts at the rear outlet of the synchronizing flow divider valve 43, extends along the other side of the chassis, and connects to the oil inlet of the power unit 12 located at the rear of the vehicle, enabling synchronous oil supply to the rear-end actuators. Both oil circuits adopt a high-pressure resistant design, and the interfaces use conical seals or O-ring seals to ensure no leakage under high-pressure conditions.

[0074] The return oil path of each power unit 12 is realized through the first return oil pipe 44. The first return oil pipe 44 has a dual parallel structure, connecting the return oil ports of the front and rear power units 12 respectively. The two return oil pipes converge in the middle of the chassis and are uniformly connected to the inlet return oil channel of the multi-way valve group 37, forming a closed-loop return oil path. At the same position on the first return oil pipe 44 and the high-pressure oil pipe 42, a two-way throttle valve 41 is provided. The two-way throttle valve 41 is a symmetrical adjustable damping element, which has a rotatable needle valve and a two-way flow channel inside. Whether the oil flows forward through the high-pressure oil pipe 42 to supply oil to the power unit 12, or flows backward through the first return oil pipe 44 to return oil from the power unit 12, it can provide the same throttling resistance. This throttling action is used to control the extension and retraction speed of the power unit 12, avoiding impact, vibration or uncontrolled drop caused by excessive instantaneous oil flow, and realizing smooth start-up and uniform speed operation. The two-way throttle valve 41 does not have a one-way bypass and does not participate in pressure protection. It is only used as a speed regulation device. Its opening degree can be adjusted manually or by preset according to the working conditions without affecting the system pressure characteristics.

[0075] Specifically, the multi-way valve group 37 includes multiple individual valve bodies 36, each valve body 36 being a three-position control valve. The three-position control valve has three states: advance, stop, and reverse return.

[0076] Specifically, the multi-way valve assembly 37 consists of multiple independent individual valve bodies 36 integrated in parallel on the same valve block body. Each individual valve body 36 is a standardized three-position control valve unit with an identical structure. Internally, it employs a spool valve structure, consisting of a valve core, valve body sleeve, return spring, and operating handle or electromagnetic drive mechanism. All valve bodies 36 share the same high-pressure oil inlet and return channels, but each has two independent working ports, enabling independent control of individual actuators. The individual valve bodies 36 are arranged in a straight line within the valve block, with adjacent valve bodies isolated by internal oil passages to ensure that each control loop does not interfere with the others, preventing cross-pressure or malfunction.

[0077] Each individual valve body 36 is a three-position control valve, whose valve core can switch between three fixed axial positions, corresponding to three working states: "advance", "stop", and "reverse return". The three states are precisely controlled by an external operating mechanism (such as a manual valve stem, an electro-pneumatic proportional solenoid, or a pneumatic control unit). When the valve core is in the "advance" state, high-pressure oil enters the valve body through the inlet port and is guided to the first working port through the internal channel of the valve core. At the same time, the second working port is connected to the return port, forming a unidirectional oil flow path, driving the connected power unit 12 to move in one direction (such as the hydraulic cylinder extending). When the valve core is moved to the "stop" state, the closed structure in the middle of the valve core simultaneously cuts off the connection between the inlet port and the two working ports, so that both chambers of the power unit 12 are closed, the oil cannot flow, and the actuator is "locked" in the current position. Even if the external load changes or the pipeline pressure fluctuates, there will be no spontaneous displacement, realizing the hovering positioning function during operation. When the valve core is further moved to the "reverse return" state, the inlet port is connected to the second working port, while the first working port is connected to the return port. The oil flow direction is reversed, and the power unit 12 moves in the opposite direction (such as the hydraulic cylinder retracting), completing the action cycle.

[0078] The switching process of the three-position control valve is smoothly transitioned through mechanical or electronic means. The valve core is equipped with positioning grooves or magnetic retention structures in each of the three positions to ensure that it will not mis-displace due to vibration or oil pressure fluctuations without external force. In the "stop" state, the valve core's sealing surface adopts a double sealing design of conical surface or O-ring to ensure no internal leakage in the high-pressure oil circuit and guarantee reliable locking of the actuator. The operation mode of each individual valve body 36 can be independently set. For example, the valve body 36 used to control the lifting cylinder is operated manually by the driver via the valve stem, while the valve body 36 used to control the self-unloading lifting is driven by electrical signals from the superstructure control panel, realizing multi-source, asynchronous, and parallel control.

[0079] Because each individual valve body 36 possesses complete "propulsion-stop-reverse return" three-state control capabilities, the multi-way valve group 37 can simultaneously and independently manage multiple hydraulic actuators. Each unit can start and stop independently, move in both directions, and hover precisely without interdependence. This design eliminates the need for separate control valve groups for each type of superstructure in the hydraulic system of this invention. By combining multiple individual valve bodies 36 of uniform specifications, it can flexibly adapt to the differentiated hydraulic action path requirements of different superstructures such as self-unloading, mixing, and lifting. The system is compact, highly versatile, and easy to maintain, serving as the underlying execution core for achieving the function of "adapting multiple types of superstructures to the same chassis".

[0080] Optionally, as shown in Figure 11 in another specific embodiment, a solenoid valve 47 is added to the oil inlet or return line of the power unit 12 (such as a lifting cylinder, a self-unloading lifting cylinder, etc.) to realize independent, remote, and precise start-stop control of the action performed by a single power unit, serving as an auxiliary or redundant protection unit for the main control logic of the multi-way valve group 37.

[0081] Specifically, as shown in Figure 12, the multi-way valve group 37 has a first control circuit and a second control circuit. The first control circuit is used to control the lifting and lowering actions of multiple power units 12, and the second control circuit is used to control the hydraulic power unit 70 of the upper structure 2.

[0082] As shown in Figures 11 and 12, the variable oil pump 32 can provide power for the superstructure with different flow requirements. It is equipped with a normally closed quick-connect coupling, which can be connected to the hydraulic power unit 70 of the superstructure 2 with a reversing and pressure control mechanism, or connected to the hydraulic power unit 70 of the self-unloading superstructure 2 through the multi-way valve group 37 at the OUT / IN2-4 interface.

[0083] The multi-way valve group 37, by setting independent first and second control loops, realizes separate control of the lifting action of the power unit 12 and the operation of the hydraulic power unit 70 of the superstructure 2. The first control loop connects the variable oil pump 32 in the hydraulic system to the power unit 12 and is only used to drive the power unit 12 to complete the lifting action. The second control loop connects the variable oil pump 32 to the hydraulic power unit 70 of the superstructure 2 and is dedicated to driving the superstructure 2 to perform its operation function. The two hydraulic paths are completely separated within the multi-way valve group 37 and do not interfere with each other, effectively avoiding the problems of power output conflict, response delay or reduced control accuracy caused by shared circuits in traditional systems. During the rapid disassembly and assembly of the chassis 1 and the superstructure 2, the first control loop can accurately control the lifting of the power unit 12, so that the subframe 200 and the frame 100 can reliably fit or separate. When the superstructure 2 is operating, the second control loop can independently supply power to the hydraulic power unit 70, ensuring that the function of the superstructure is not affected by the lifting action of the chassis, thus realizing efficient coordination of functional decoupling and system response.

[0084] Specifically, each power unit 12 is equipped with an explosion-proof valve 46. When a sudden leak or burst occurs in the hydraulic system during the switching of the drive unit 2 between the assembly and disassembly positions, causing a sudden drop in hydraulic oil pressure, the explosion-proof valve 46 can immediately respond and close the oil passage of the corresponding power unit 12, preventing further loss of hydraulic oil. This maintains the stability of the connection between the locking device 11 and the locking latch, preventing the unit 2 from falling unexpectedly due to loss of hydraulic support. This effectively improves the safety and reliability of the chassis 1 and the unit 2 during assembly and disassembly operations. This structure, by independently configuring an explosion-proof valve 46 on each power unit 12, achieves precise protection for each hydraulic circuit. Even if a local pipeline fails, it will not affect the normal operation of other power units 12, ensuring the safe hovering of the unit 2 in any position.

[0085] The assembly process between the vehicle superstructure and chassis using the technical solution of this application is as follows: When assembling the superstructure 2 of the engineering vehicle with the chassis 1, the superstructure 2 is first anchored to the ground via its superstructure support legs 22. Under the control of the operator, the chassis 1 is slowly reversed so that the centerline of the chassis frame is basically aligned with the longitudinal centerline of the superstructure subframe, and enters the "gap space" enclosed by four sets of mechanical support legs. This space is a rectangular area enclosed by the inner side of the mechanical support legs, and its size is designed to be slightly larger than the width of the chassis frame to ensure that the chassis does not interfere with the mechanical support legs during reversing. When the chassis frame continues to move backward until each mechanical support leg bracket at the bottom of the superstructure subframe (located inside the longitudinal beam of the subframe) is directly opposite the corresponding hydraulic cylinder assembly installed on the chassis frame, the chassis temporarily stops. At this time, the conical push head 48 of each hydraulic cylinder is vertically located directly below the preset limiting groove in the mechanical support leg bracket of the superstructure subframe, and the axes of the two are basically coincident in the vertical direction, with only slight lateral or longitudinal offset possible.

[0086] After confirming the position, the operator activates the chassis power take-off (PTO), connecting the engine to the hydraulic system. The operator then engages the electromagnetic clutch 31 via electronic control, initiating the operation of the variable displacement pump 32. Subsequently, the operator manipulates the chassis multi-way valve group 37 to direct hydraulic oil to the four power units. High-pressure oil sequentially flows through the multi-way valve group and high-pressure oil pipes into the rodless chamber of each hydraulic cylinder, pushing the piston rod outwards. Each hydraulic cylinder's piston rod is topped with a conical pusher. The pusher's surface is a precision-machined conical structure with a taper of 1:10 to 1:15 and a surface roughness Ra ≤ 1.6 μm, ensuring good guidance and self-centering capability when in contact with the inner wall of the limiting groove. When the conical pusher contacts the limiting groove opening, due to the geometric self-centering characteristics of the conical surface, even with lateral or longitudinal deviations within ±15 mm, the pusher can automatically correct its position and achieve center alignment upon contact with the inner wall of the limiting groove through inclined sliding and friction. This is a sensorless, purely mechanical "passive self-alignment" mechanism. If the deviation exceeds this range (such as excessive deviation of the chassis reversing trajectory), the system will prompt the operator to fine-tune the chassis's lateral or longitudinal position until all four conical push heads smoothly contact the inner wall of their respective limit grooves, without jamming or abnormal single-point force.

[0087] After the four sets of conical pushers are fully engaged with the limiting grooves and achieve stable contact, the operator releases the locking mechanism of the four upper structure outriggers 22 on the upper structure subframe and gradually retracts or disassembles the mechanical outriggers. At this point, the entire weight of the upper structure is borne by the four hydraulic cylinders on the chassis through the cooperation of the conical pushers and the conical surfaces of the upper structure outriggers 22, and the upper structure is in a "four-point suspension" state. The operator must visually confirm that there are no other supports (such as ground anchors, pads, temporary cables, etc.) or interference with the ground or surrounding facilities on the upper structure, ensuring that it is completely supported by the hydraulic system.

[0088] After confirming everything is correct, operate the chassis multi-way valve group to put the hydraulic cylinder into "micro-descent" mode, slowly releasing the pressure in the rodless chamber of the hydraulic cylinder, allowing the superstructure to descend smoothly under its own weight. The descent speed is controlled by the throttling characteristics inside the multi-way valve group to avoid impact. As the superstructure subframe gradually approaches the upper surface of the chassis frame, the pre-set guide device on the superstructure subframe (a symmetrically arranged guide slider or guide boss structure) begins to contact the corresponding positioning groove on the chassis frame. The positioning groove is an inverted V-shaped groove with an upward opening, an inner wall angle of 90–120°, a depth of 10–20 mm, and a surface hardened for wear and impact resistance.

[0089] As the superstructure continues to descend, the guide device slides into the inclined surface of the V-shaped positioning groove. Utilizing the geometric convergence characteristics of the V-shaped groove, it automatically guides the superstructure subframe to achieve precise positioning in both longitudinal (front-to-back) and lateral (left-to-right) dimensions. The inclined surfaces on both sides of the V-shaped groove constrain the lateral offset of the superstructure, while the length of the groove bottom limits longitudinal displacement, ensuring that the superstructure is centered before it is fully fitted. When the superstructure subframe finally descends and contacts the upper surface of the chassis frame, the conical contact between the conical pusher and the limiting groove is released, maintaining an axial gap of 5–10 mm between them to avoid structural deformation caused by rigid compression. At the same time, it ensures that the pusher remains inside the superstructure support leg 22 and is not completely disengaged, providing a reset reference for subsequent rapid disassembly.

[0090] At this point, the operator places the multi-way valve group operating lever in the neutral position, cutting off the hydraulic cylinder oil inlet circuit. The lifting system stops operating, and the superstructure is in a "suspended and engaged" state. Check that the positioning guide device is fully embedded in the V-shaped positioning groove, confirming that the superstructure is not skewed or warped front to back or left to right, and that the four corners are evenly engaged. Then, activate the quick-locking device: Laterally fasten the U-bolt (forged from high-strength alloy steel with threads at both ends) located on the chassis frame to the pre-set locking latch groove (a rectangular open groove with no chamfered inner wall to ensure no lateral movement after the bolt is engaged) on the longitudinal beam of the superstructure subframe. Press down the handles at both ends of the U-bolt (a lever-type clamping mechanism), causing the bolt to engage with the chassis frame under the locking force. The bolt body applies a downward clamping force to the superstructure subframe, eliminating any possible small gaps between them.

[0091] If the inspection reveals that there are still local gaps (≤2mm) on the mating surfaces, the effective length of the bolt can be shortened by rotating the adjusting nuts at both ends of the U-bolt, further increasing the tightening force until the subframe of the superstructure and the chassis frame achieve a rigid connection with no looseness or abnormal noise. At this point, the superstructure and chassis have achieved a mechanically rigid connection and possess the structural strength to withstand driving loads.

[0092] Finally, the hydraulic system and the chassis hydraulic system are connected via a pre-installed quick-connect coupling (a standardized high-pressure hydraulic quick-connect coupling with a self-sealing valve core), ensuring that the power required for the superstructure operation can be directly supplied by the chassis hydraulic system. Simultaneously, the electrical control harness of the superstructure is connected to the pre-installed electrical connectors on the chassis, enabling the connection of control functions such as lights, signals, and emergency stop. At this point, the superstructure installation is complete, and the vehicle can proceed to the next operating condition.

[0093] When it is necessary to separate the upper structure 2, first ensure that the upper structure outriggers 22 have been reinstalled and placed on a hard ground. Operate the first control circuit of the multi-way valve group 37 to switch to the reversing return state. The hydraulic oil flows back to the inlet of the multi-way valve group 37 through the first return oil pipe 44. The power unit 12 slowly descends, and the conical pusher completely exits from the limit groove 25 and returns to its original position. Then, unlock the locking device to disengage the U-bolt from the locking buckle. At this time, the upper structure 2 is only supported by the upper structure outriggers 22. The chassis 1 reverses away to complete the separation. During the separation process, if the hydraulic system experiences pipeline leakage or pipe burst, the explosion-proof valves 46 on each power unit 12 immediately close the oil circuit to prevent hydraulic oil loss and ensure the safety of the upper structure 2 when hovering before and after separation.

[0094] The technical solution adopted in this application has the following technical effects:

[0095] 1. The same engineering vehicle chassis can be quickly fitted with various superstructures such as dump trucks, mixers, and truck cranes, which greatly improves the utilization rate of the chassis and reduces the purchase and idle costs of the whole vehicle.

[0096] 2. The PTO power output is intelligently controlled by an electromagnetic clutch, providing power to the superstructure only when needed, avoiding the hydraulic system from idling, and significantly reducing energy consumption and the risk of oil temperature rise.

[0097] 3. It adopts an integrated structure of automatic centering with a conical pusher, precise positioning with a V-groove, and hydraulic synchronous lifting and mechanical locking, achieving one-click quick change without hoisting, improving efficiency by more than 80%.

[0098] 4. A synchronous flow divider valve is used to achieve smooth, safe, and synchronous lifting and separation of the four hydraulic cylinders.

[0099] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0100] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0101] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An engineering vehicle, characterized in that, include: The chassis (1) includes a frame (100), which is provided with a plurality of locking devices (11) and a hydraulic system; the superstructure (2) includes a subframe (200) on the superstructure (2), which is provided with locking buckles (21) on the outer side of the subframe (200), and the locking buckles (21) are provided in a one-to-one correspondence with the locking devices (11). The chassis (1) and the superstructure (2) are detachably connected by the locking devices (11) and the locking buckles (21). The superstructure (2) includes at least one of the following: a dump truck superstructure, a concrete mixer truck superstructure and a crane truck superstructure. The hydraulic system has an assembly position that allows the superstructure (2) to be located above the chassis (1) and the subframe (200) to be in contact with the frame (100), and a separation position that allows the superstructure (2) to be separated from the chassis (1).

2. The engineering vehicle according to claim 1, characterized in that, The chassis (1) includes: a power unit (12), which is provided in multiple ways, and each power unit (12) is located on the outside of the frame (100); a positioning groove (13), which is provided in multiple ways, and each positioning groove (13) is located on the outside of the frame (100), the positioning grooves (13) are spaced apart along the length direction of the frame (100), and at least one positioning groove (13) is located on one side of the locking device (11).

3. The engineering vehicle according to claim 2, characterized in that, The upper structure (2) includes: upper structure support legs (22), four upper structure support legs (22) are provided, the upper structure support legs (22) are located on the outside of the subframe (200), two upper structure support legs (22) are provided on each side of the subframe (200), the upper structure support legs (22) on both sides are symmetrically arranged, the upper structure support legs (22) on the same side are spaced apart along the length direction of the subframe (200), and the upper structure support legs (22) are detachably connected to the subframe (200); guide device (23), the guide device (23) is located on the outside of the subframe (200), part of the guide device (23) protrudes from the lower edge of the subframe (200); bracket (24), the two ends of the bracket (24) are respectively connected to the upper structure support legs (22) on both sides, and the bracket (24) is provided with a limiting groove (25).

4. The engineering vehicle according to claim 3, characterized in that, The locking device (11) includes a U-shaped bolt buckle. When the upper garment (2) is in the assembly position, the U-shaped bolt buckle is locked to the locking buckle (21). The length of the U-shaped bolt buckle is 10~20mm.

5. The engineering vehicle according to claim 3, characterized in that, The power unit (12) is a hydraulic cylinder. The piston rod of the hydraulic cylinder is provided with a conical push head (48). When the upper device (2) is in the assembly position, the protruding part of the guide device (23) is located in the positioning groove (13), the conical push head (48) is located in the limiting groove (25), and the conical push head (48) and the limiting groove (25) are separated by a gap.

6. The engineering vehicle according to claim 3, characterized in that, The hydraulic system includes: an electromagnetic clutch (31), which is located between the PTO output shaft of the chassis (1) and the input shaft of the variable oil pump (32). The electromagnetic clutch (31) connects or disconnects the power transmission path through the type of the upper structure (2). The output end of the variable oil pump (32) is connected to the hydraulic oil tank (38), the input end of the multi-way valve group (37) and the high-pressure port of the hydraulic system power system of the upper structure (2) through a three-way connector. The output end of the multi-way valve group (37) is connected to the power unit (12) and the hydraulic oil tank (38).

7. The engineering vehicle according to claim 6, characterized in that, The multi-way valve group (37) is a three-position four-way electro-hydraulic directional valve group. The outlet of the multi-way valve group (37) is connected to each of the power units (12) through a high-pressure oil pipe (42). A synchronous flow divider valve (43) is provided on the high-pressure oil pipe (42). After passing through the synchronous flow divider valve (43), the high-pressure oil pipe (42) generates a first oil circuit (40) and a second oil circuit (45). The first oil circuit (40) is used to supply oil to the power unit (12) located at the front of the vehicle, and the second oil circuit (45) is used to supply oil to the power unit (12) located at the rear of the vehicle. Each of the power units (12) is connected to the inlet of the multi-way valve group (37) through a first return oil pipe (44). A two-way throttle valve (41) is provided at the same position on the first return oil pipe (44) and the high-pressure oil pipe (42).

8. The engineering vehicle according to claim 7, characterized in that, The multi-way valve group (37) includes multiple valve bodies (36), each of which is a three-position control valve, and the three-position control valve has three states: advance, stop, and reverse return.

9. The engineering vehicle according to claim 6, characterized in that, The multi-way valve group (37) has a first control loop and a second control loop. The first control loop is used to control the lifting and lowering actions of the multiple power units (12), and the second control loop is used to control the hydraulic power unit (70) of the upper structure (2).

10. The engineering vehicle according to claim 2, characterized in that, Each of the power units (12) is equipped with an explosion-proof valve (46).

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