附录A英文原文
A Brief Description of Lift Truck System Design
Martin W.Crouse
Abstract： In this paper, dump truck through a brief design analysis, in view of the
length of the larger features of heavy-duty dump truck, lifting the system from node Structure design and hydraulic design of the corresponding measures for the lifting of heavy truck design a certain guiding function.
Key words： heavy-duty；lifting；system 1. The main structure of dump truck
Dump truck, including the structure of the main lift system, chassis, frame, vice,component compartments,
2. lifting body design and analysis
Heavy-duty dump truck lifting system in the design process of the main issues that need to be addressed include: lifting forms of selection, in the lift car in the process of stability, before and after the bridge, the reasonableness of axle-load distribution and hydraulic system reliability. Chassis by following the design of 7.2 meters on concrete examples of the dump truck, dump truck lifting mechanism on the general idea of system design.
2.1 Compartment volume to determine initial
Chassis in accordance with the parameters: Wheelbase 3900mm +1350 mm, rear overhang 900mm, set the quality of 17500kg, and the whole 1600mm rear overhang for the request to determine car-size 5600mm * 2300mm * 1500mm. Determine the initial car position in the chassis for the car back out of the back-end chassis frame870mm. In determining the form of lifting, the need for further analysis of Count before and after the bridge and axle-load distribution of the car to verify the location of the vehicle in the second category is reasonable. 2.2 determine the form of lifting
Lift truck used mainly in the form of F-type, T-style, front-straight top form. In F-type, T-style, front-straight top three identified in the form of lifting one of the most suitable, we need three conditions on the analysis of calibration. Lift the form of the three has its own advantages and disadvantages of pre-straight-top compact structure, lifting and high efficiency. Simple process with low costs. However, after lifting the
stability of poor road conditions on the higher; F-type and T-type lifting mechanism a good degree of cross-cutting steel, smooth lifting smooth rotation, the fuel tank of the work piston short trip, but the lift coefficient than the Great.
In order to determine whether the choice of what kind of lifting the most appropriate form, the author of three cases were done on the theoretical analysis. If the selected F-type and T-type lifting form, the most important of its calculated lift coefficient comparison. By calculating the F-type forms of lifting lifting the smallest coefficient is 1.751, T-type lifting the smallest form of lift force coefficient is 1.799, it is not ideal (usually lift coefficient of 1.6 to 1.7 when the effect of better). The front straight top edge lifting the fuel tank T is greater than 8 tons of it. Taking into account the use of F-type or T-type lifting mechanism, very easy lifting, lifting the need for large tanks, but also to the triangular arm, such as demanding and difficult to achieve. Combination of the foregoing analysis, decided to adopt the prefix form of straight Lift top.
Lifting measures to improve the stability of 2.3 Due to the design of the length of the larger car, at the same time, the use of pre-straight lifting top form, so the stability of car is very important, need to take measures to improve the process of lifting carriage vehicle stability, prevent the occurrence of vehicle rollover. Dump Truck car normally used to connect the design of hinge axis and sub-frame connection, the Deputy frame through the U-bolts and connect the main frame structure. The design we have adopted a new structure, flat steel, through welding at the side of fixed with bolts on the main frame, thus greatly reducing the vehicle's center of gravity to increase stability. As the car through the hinge axis and the hinge axis to achieve the lifting Block rotation, hinge axis blocks now have a high degree of flat steel to replace the Vice-trailers will need to install seat hinge axis frame in the main beam on the wing surface below the main Frame back-end need to install a Z-shaped beams to support Block after the hinge axis, Z-shaped beam through the bolt assembly back-end fixed in the frame, while the two-axis hinge as much as possible the distance between blocks to increase to increase the car example or stability. Due to the length of the larger car, the design would have to consider the stability of devices used to increase vehicle stability, the stability of the central unit installed on the inside of the location of the former side. Car safety design in the frame around pole between the longeron, the form of simple, safe, reliable, easy to operate. After taking into account
the lifting carriage, Block Department hinge axis force is very large, and therefore hinge axis in the Block Office, to strengthen measures to be adopted to increase the hinge axis of the support seat edge.
3. Hydraulic Lift System Design
Pre-straight top-style, including the dumping of hydraulic gear pumps,hydraulic cylinder, control valve lift, valve lift, hydraulic tanks, piping, lifting mechanism. Hydraulic system we use an advanced three-loop system. Hydraulic control system schematics,. The dump truck in the three-loop system, the oil will flow to the fuel tank through the valve assembly to return to the only circuit in the oil return to tank, the pump will help to guide the valve through a separate oil circuit only be used as a return circuit, because in most excellent circuit design, the return will be installed in circuit capacity 100gpm use filters to filter the dirt to enter the pump to extend the use of pump parts life. Three-loop system, the main advantages are: to ensure that clean oil will always supply pumps, and not when the dump truck in the position or to maintain only the reliance on the oil pump in the internal volume rotation. 3.1 The main components to choose
Hydraulic system is mainly used hiwassee systems, hydraulic cylinder hiwassee selected multi-level cylinder sleeve.
3.2 hydraulic cylinder installation to determine the location
The installation of hydraulic cylinder straight-top car and the driver's request there is enough room between that having studied the arrangement of second-class chassis, the cab behind the need to move the location of muffler. The abolition of the Vice-frame, hydraulic oil tanks need to install a beam in the main frame between the two, using the hole on the main frame, the design of the installation of a hydraulic cylinder assembly seat. Block with bolts installed in the main frame about a fixed beam, the hydraulic cylinder support shaft and then installed in the installation of seat, hydraulic cylinder brackets before the board in the car.
4. Concluding remarks
These are the lift truck system design process, the main features of the design is the length of the vehicle used in large dump truck front straight top lifting body, the hydraulic system for the three-loop system, the use of pump valve all-in-one structure, working principle of simple and novel structure; At the same time, through the
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