Design of frame for semitrailer - 7 t load-carrying plate carrier

Contents

Contents

Introduction

1 Design Analysis

2 Power frame calculation

2.1 Calculation of spar loads

2.2 Calculation of rivet joints

2.2.1 Rivets connecting cross-bars with spars

2.2.2 Calculation of rivet joints for the cut

2.2.3 Calculation of rivet joint for crushing

2.2.4 Rivet selection

3 Frame strength calculation

3.1 Calculation of spars for bending strength

3.2 Selection of floors (plates) for riveting connection of spars and crossbars

4 Evaluation of the technical level and quality of the frame

5 Frame Operating Manual

5.1 Semitrailer Maintenance

5.1.1 Daily Maintenance

5.1.2 First Maintenance

5.1.3 Second Maintenance

5.1.4 Seasonal Maintenance

5.2 Storage and preservation of semi-trailers

5.3 Long-term preservation

5.4 Maintenance and maintenance of trailers and semi-trailers under preservation

5.5 Depreservation of semitrailer

Conclusion

Literature

Summary

In this course design, a frame for a semi-trailer is designed - a 7-ton load-carrying plate trailer, the prototype of which is a single-axle semi-trailer  - UPL-0906  plate trailer (the main tractor of the semi-trailer is the ZIL130V1 truck tractor). Power and strength calculations of the frame were made, the main parameters and dimensions of individual frame units and components were determined, the design of the designed frame was analyzed, the maintenance of the semi-trailer, its lubrication and preservation during long-term storage were described, and the operating manual was given.

Introduction

The specialization of general-purpose road transport is due to the need to improve the quality and efficiency of transportation of household goods, to reduce the labor intensity of loading and unloading. Specialized road transport is one of the links of complex mechanization of production and technological processes in industry, construction and other sectors.

The use of road trains provides a number of advantages over single vehicles of the same carrying capacity:

- reduction of axle load at the same lifting capacity;

- the fullest use of the available engine power reserve;

- Increase in car productivity (despite the reduction of the average technical speed by 1520%) compared to single cars by 2 times;

- reduction of fuel consumption per ton of transported cargo by 2030%;

- reduction of transportation costs by 2030%;

- reduction of container coefficient and rolling stock cost.

Design Analysis

Frame of semitrailers is the main bearing element. The frame usually consists of two longitudinal beams, called spars. They are interconnected by means of crossbars. Spars are made of thick-sheet steel with a thickness of 5 to 12 mm, and crossbars - of steel with a thickness of 4 to 8 mm or of pipes. The profile of spars is usually standard profiles - these are channels or I-beams. For frames of trailers and semi-trailers, crossbars of open or closed profile are used as crossbars. Cross bars of an open profile are usually channel or I-section, closed profile are box or tubular.

In automotive practice, trailers and semi-trailers with ridge-type frames are used, having a box-shaped section of beams that provide the frames with high torsional stiffness.

The connection of the crossbars to the spars may be different. Crossbars are attached to flanges of spars or to their walls depending on degree of loading of spars at frame torsion. It is also possible to combine the crossbars - to one of the shelves and the wall of the spar.

A reduction in the weight of the frame should not be accompanied by a weakening of the structure or an increase in its cost. Currently, designers of a number of companies seek to reduce the spacing of the transverse frame from 610 to 457 mm, which leads to an increase in metal consumption and therefore the weight of the structure. However, reducing the spacing of the crossbars reduces the likelihood of damage to the cargo platform floor during loading and unloading operations. In addition, frames are installed on semitrailers, reinforced in the area limited by the support plate of the coupling device and the support rollers of the semitrailer.

The frames of almost all semi-trailers are made of channel section rolled stock of three types, which are best resistant to bending defects: rolled stock, welded plate and ladder (lattice). At points of change in cross-section, the spars are usually reinforced by additional plates that are attached to the lower shelf by welding. The reinforcing elements are usually concentrated in the area between the coupling device and the support rollers of the semi-trailer in which the bending stress is most important. Box section reinforcement elements having a closed profile are also used. Steel rolled stock does not provide significant weight savings and is therefore useful for heavy semi-trailer frames. Considerable savings can be achieved by using channel-section welded beams, which are manufactured in exact accordance with the nature of the stresses in the zone of each particular semitrailer, but their cost is significantly higher than that of rolled ones. Great attention is paid to ensuring sufficient torsional stiffness of the frame. The middle part of the frame located between the support plate of the coupling device and the semi-trailer trolley mainly works on torsion. Torsional stiffness of frame is increased due to connection of upper and lower flanges of spars by means of crossbars made in full height of spars profile, slashes fixed by welding on outer side of spars and installation of crossbars arranged in pairs above each other, one of them being attached to lower flange of spars, and the other to upper one. The rigidity of the frame is also increased by the installation of additional crossbars at the rear and in the central portion, preferably a tubular section having the best torsional resistance.

The weak point of semitrailers frames is the attachment points of trolley suspension brackets. The trolley bracket shall be shaped to secure them to the semitrailer frame and shall cover the spar.

The carried out analytical studies of the frame of the semitrailer revealed the structural imperfection of its individual units and parts, consisting in its relatively high metal consumption, cost, significant labor intensity of maintenance and repair, and less processability. Given this and using existing domestic and foreign patent and literary sources, we come to the conclusion that it is advisable to use a riveted ladder frame.

In the design of this prototype, the connection of the crossbar and spar using rivets is used.

In the semi-trailer  - a plitovoza of MZAP932620000010 of ladder type. Spars have variable cross-section, which reduces metal consumption of the structure. Spars are connected to crossbars by rivets. The trailer is designed to carry goods as part of a road train on roads that allow the movement of road transport with an axial load of up to 8 tons.

Evaluation of technical level and frame quality

The designed frame consists of two spars and six cross-sections of channel section, as well as twelve plates, which give the structure additional rigidity. All frame members are joined by riveted joints. The choice of rivet joints is due to the studies of the semitrailer frame, which made it possible to identify the relatively high metal consumption of individual frame units and parts, the significant labor intensity of maintenance and repair, and the lower processability of production when using welded joints. Given this and using existing literary sources, we concluded the integrity of the use of the rivet-type ladder frame.

Since the frame of the semitrailer mainly works on torsion when moving along various roads, only the mode of movement of the semitrailer was taken into account when calculating stresses, and these are characteristic of the same two frame sections that were considered during bending.

The main parameter for the designed frame is load capacity. On assignment for the course project, it amounted to 5 tons. Compared to the prototype, the load capacity has decreased, which will reduce cost.

The technical level of the designed frame is not inferior to analogues, meets all modern standards and requirements for structures. The quality is due to the high reliability and durability of the frame parts. The designed frame has a high degree of standardization and unification due to the use of a large number of standard products and materials regulated by the main standard.

Frame Operating Manual

During operation, it is necessary to fix the transported goods and prevent their movement during movement.

During loading and unloading operations, do not allow impact and concentrated loads, characteristically exceeding the permissible ones, which lead to cracks in spars and frame destruction.

During operation at each maintenance, the frame must be inspected, washed and painted, at each Maintenance-2 it is necessary to monitor the attachment of cross-members with spars and spring brackets, the quality of riveting joints. Frame structure elements: cross-bar spars shall have no traces of corrosion, cracks and other defects. More than two transverse seams in the spar are not allowed during frame repair.

During preservation, the frame is painted and lubricated.

When the frame is disposed of, it is dismantled and further processed at metallurgy enterprises.

5.1 Semitrailer Maintenance

Maintenance works are preventive, so they must be carried out on time and must be carried out. Maintenance provides for fastening, lubrication, adjustment, harvesting and other types of work, which are carried out, as a rule, without removing and disassembling the trailer units.

Maintenance of semi-trailers according to periodicity, performed operations and labor intensity is divided into the following types: daily maintenance (ES); first maintenance (TO-1); second maintenance (TO-2); seasonal maintenance (CO) when preparing a trailer (semi-trailer) for winter and summer operation. Seasonal service will be carried out in autumn or spring, respectively, with the next TO-2.

Frequency of TO-1 and TO-2 is set depending on operating conditions.

The trailer shall be thoroughly washed and cleaned before inspection and maintenance. For high-quality performance of works, it is recommended to organize posts equipped with the necessary tools and devices. Maintenance shall be carried out in conditions that prevent dirt and dust from entering the trailer assemblies.

Work related to adjustment and maintenance of brake system instruments, hydraulic system units and platform lifting mechanism shall be carried out by specialists with experience in adjusting such systems. Disassembling and repair of the units removed from the trailer must be carried out in workshops equipped with the necessary tools and devices to monitor the adjustments made .

5.1.1 Daily Maintenance

Daily maintenance is one of the main types of semi-trailer care. The daily service includes: preparation of the semi-trailer for departure; inspection on the way (on the shafts and stops); semitrailer maintenance upon return to ATP.

Before leaving ATP inspect and check:

semitrailer completeness, platform condition, frame condition, springs, wheels, tyres, support device and license plates;

air pressure in tyres, presence and tightening of all nuts of wheels attachment;

serviceability of locking mechanism, serviceability and attachment of body stop;

reliability of coupling

reliability of coupling, operation of lighting and signalling devices.

Inspection on the way provides for:

check for the degree of heating of wheel hubs, inspection of tyres and wheel attachment and removal of foreign objects stuck in the tread or between twin tyres;

check of tractor coupling reliability with semi-trailer .

At the end of operation it is necessary to:

clean the semi-trailer from dirt and dust, wash, wipe the rear lights, direction indicators, license plate, light masking devices with soft cloth;

inspect the tyres and remove foreign objects stuck in the tread.

Check presence of all nuts for wheels attachment.

5.1.2 First Maintenance

During TO-1 it is necessary to perform the whole scope of daily maintenance, lubrication works and additionally perform the following:

check the condition of springs frame, undercuts, tightening of pin nuts and ramps of spring lugs attachment with root sheets, tightening of bolts and cup of springs, nuts of spring straps, screws for attachment of spring brackets inserts. If necessary, tighten the connections.

Check condition of wheels, presence of valve caps and air pressure in fully cooled tyres. Select tires with local damage to be sent for repair.

Check condition and operation of installation supports (jacks). Force on handle with length of 345 mm at lifting and release without load must be 1 kgf.

5.1.3 Second Maintenance

During TO-2 it is necessary to perform the whole scope of works of the first maintenance and additionally perform the following:

check the correct location (absence of distortions), condition and attachment, if necessary, eliminate the distortion, check and, if necessary, adjust the wheel hub bearings;

check riveting joints of frame and condition of spars, crossbars, flooring, attachment of brackets, condition and reliability of springs attachment. Make sure that there is no longitudinal displacement of sheets indicating cutting of the central bolt and there are no cracks on the sheets;

check tightening of attachment nuts of the towing hook housing from the transverse frame and serviceability of the spare wheel lifting mechanism;

check the attachment of the platform, splashes and, if necessary, attach; check condition and attachment of middle strut;

check the state of insulation of wires and their attachment, correct operation of the lighting and alarm system.

5.1.4 Seasonal Maintenance

Seasonal maintenance includes all the work of the next second maintenance and additionally: painting (if necessary) of the semi-trailer or grinding and painting of damaged places; check at semi-trailers of sides, platform floor.

5.2 Storage and preservation of semi-trailers

For long-term storage of semi-trailers, it is recommended to install under the canopy. Semitrailers shall be preserved during storage or interruption of operation for more than one month.

Before preservation semitrailer must be unloaded, cleaned of dust and dirt. All areas with corrosion marks are cleaned with sandpaper or a metal brush followed by wiping with rags wetted in white alcohol or gasoline to remove the fat layer. Cleaned places are painted. The thickness of the paint layer must be restored. Before preservation, all points of lubrication of semitrailer are abundantly lubricated according to lubrication map .

At setting of semitrailer for short-term preservation (period up to 3 months), perform the following operations:

cover all unpainted external surfaces of semi-trailer parts and assemblies with neutral lubricant;

clean the tool and accessories from dirt, lubricate them with neutral lubricant and wrap them with paper or material;

unload springs and tires by hanging and placing on goats. To hang the semitrailer under the middle frame spars in the area of support devices and under suspension balancers, install safety gables;

it is desirable to remove all wheels and disassemble them. Wipe the chambers and interior of the tires with talc. Install the tyres, bring pressure in them and install the wheels on the semi-trailer, tyres and other parts must be protected from direct exposure to sunlight;

set the handle of the manual release valve to the position of the released semitrailer, extendable struts of the semitrailers support devices and the pivot to be abundantly lubricated with solidol, close the connecting heads with covers.

5.3 Long-term preservation

In case of long-term (over 6 months.) storage, which does not require constant readiness of the trailer for operation, it is necessary to carry out the above works and additionally perform the following:

to avoid damage of wheels rubber from atmospheric influences, remove the wheels and store them in a dry closed room.

5.4 Maintenance and maintenance of semi-trailers under preservation

Regularly (once a month) carefully review the semi-trailer and eliminate the detected faults and shortcomings.

Seasonally (after six months), it is necessary to paint damaged surfaces, lubricate the semitrailer in full according to the lubrication map.

Once a year (in autumn) it is necessary: to completely disassemble the wheels and units of the braking system to check the condition of all parts. Pay special attention to the condition of rubber, felt, leather and cardboard parts. Replace them if necessary.

5.5 Depreservation of semitrailer

During depreservation of semitrailer and its preparation for operation it is necessary to:

Clean the mechanism surfaces, tools and accessories from preservation lubricants and oils;

check the tyre pressure (if necessary, bring it to normal value);

remove semitrailer from supports (goats), check reliability of wheels attachment nuts tightening and perform check run of semitrailer for 510 km, during which check operation of all mechanisms. The defects found should be eliminated.

Conclusion

The main parameters for designing the frame of the semi-trailer is the carrying capacity and overall dimensions of the transported goods. Since in this course project we referred to the prototype semi-trailer UPL-0906, designed to carry floors and coatings up to 6 m long and up to 3 m wide, the main indicator was load capacity.

The designed frame with a lifting capacity of 7 tons has 2 spars connected to each other by 6 crossbars, a brace, 8 corners and 16 slashes.

I believe that the task set on the course project has been completed and the designed frame will be able to find application on ATP.

Literature

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Anuryev. V.I. Handbook of the designer-machine builder: in 3-t.T. 3 - 6th ed., Conversion. and supplement. - M: Engineering, 1982 -576s.

Pavlov V.A., Mukhanov S.A. Transport trailers and semi-trailers. -M.: Military building, 1981191s.

Machine details: Atlas of structures/under the general edition. D.N. Reshetov. M.: Mechanical Engineering, 1992 -352s.

Bokov V.N., Fadeev S.P. Machine details: atlas. - M.: "Higher School" 1969280c.

Cars ZIL130, ZIL -138 and their modifications: Operating Manual. - M.: Engineering, 1985280s.

Cars, buses, trolleybuses, forklifts, trailed train. - M: NIINavtoprom, 1983. – 244 pages.

Yakobashvili A.M. Specialized rolling stock for freight transportation. - M.: Transport, 1988. – 224 pages.