Trucks with a fixed flatbed body

Transcription

1 General information General information Trucks with fixed flatbed body are mainly used for transporting e.g. general cargo, building materials and construction containers. The bodywork is regarded as being torsionally weak. The instructions in this document were developed to optimise the vehicle with regard to the following factors: Lowest possible sensitivity to frame oscillations that cause discomfort Load sharing Selection of attachment type and the location of attachments The instructions assume that the bodywork is designed as a torsionally weak unit. More information on troubleshooting and the elimination of frame oscillations that cause discomfort is found in the document Discomfort caused by vibrations More information is found in the following documents: Selecting the subframe and attachment Subframe design Discomfort caused by vibrations Axle weight calculations Weighing equipment Scania CV AB 2017, Sweden 1 (9)

2 Preparing the vehicle with options from the factory Order finished solutions and preparations from the factory. Retrofitting will lead to higher costs. General information More information on finished solutions and preparations that can be ordered from the factory is found on the Scania Truck Bodybuilder website. Scania CV AB 2017, Sweden 2 (9)

3 Try to achieve as short an axle distance as possible to reduce the risk of frame oscillations that cause discomfort. The maximum permitted axle weight limits how short the axle distance may be. Position the bodywork as far forward as the maximum permitted front axle weight allows. The bodywork centre of gravity should be as low as possible to reduce the rolling moment. Contact a Scania dealer for more information about the vehicle s construction. Scania CV AB 2017, Sweden 3 (9)

4 Designing the subframe Trucks with a fixed flatbed body are usually constructed with a subframe. The advantages are as follows: Even distribution of the load Dampening of frame oscillations that cause discomfort Greater possibility of correct location of the foremost attachments according to Scania s recommendations 1 Determine the subframe s dimensions taking the requirements of the bodywork into consideration. Crossmembers can either be placed on top of the subframe side members or be integrated at the same level as the subframe. The illustration shows an example of a construction where the crossmembers are integrated at the same level as the subframe. Note: The location of the crossmembers can affect the clearance to the wheels. 2 Example of a frame construction where the crossmembers are integrated at the same level as the subframe (1). The subframe is attached to the chassis frame (2) Scania CV AB 2017, Sweden 4 (9)

5 The subframe moves in relation to the chassis frame due to torsional movements that occur when the vehicle is in motion. The movement is dampened by the friction that occurs between the subframe and chassis frame. For the friction to be as great as possible, the subframe must follow the shape of the chassis frame and have as great a contact area as possible to the frame side members, see illustration. The subframe must have as great a contact area as possible to the frame side members Subframe location The subframe must be pulled forward and attached to the chassis frame as close to the foremost front axle as possible. This decreases the load on the chassis frame and reduces the risk of frame oscillations that cause discomfort. Maximum permitted distance between the centre of the foremost front axle and the front edge of the subframe is 600 mm, see illustration. Use of the foremost body adaptation bracket, which is factory-fitted, ensures that the subframe is drawn sufficiently far forward Scania CV AB 2017, Sweden 5 (9)

6 Selection and location of attachments IMPORTANT! Design the attachments and fit the body adaptation brackets so that the vertical forces from the bodywork do not cause high torsional forces in the frame side members. High torsional forces in the frame side members can cause damage to the chassis frame. Minimise the transfer of torsional movements from the chassis frame to the subframe When the vehicle is in motion, torsional forces arise which can generate torsional movements in the chassis frame, see illustration. Transfer of torsional movement from the chassis frame to the bodywork must be minimised to counteract high torsional forces in the bodywork and its attachments Torsional forces that can generate torsional movements in the chassis frame when the vehicle is in motion. Scania CV AB 2017, Sweden 6 (9)

7 IMPORTANT! Minimise the transfer of torsional movement from the chassis frame by using flexible attachments between the subframe and chassis frame in the front section of the vehicle. Follow Scania s guidelines for the location and selection of attachment type and body adaptation brackets. More information on body adaptation brackets, their location and selection of attachment type is found in the following documents: Bodywork attachment Selecting the subframe and attachment More information on body adaptation brackets and the location of holes is found in the vehicle s ICD (Individual Chassis Drawing). Scania CV AB 2017, Sweden 7 (9)

8 Attachments in the front section of the vehicle (A) Fit the subframe using flexible attachments that allow the following movements in relation to the chassis frame: Longitudinal displacement Certain upward movement The size of the movements depends on driving conditions and the torsional rigidity of the load carrier. The attachments must control the sideways movement of the subframe. A B C D Location of the foremost attachment To counteract any frame oscillations, the foremost bodywork attachment point must be as close to the foremost front axle as possible. Maximum permitted distance between the centre of the foremost front axle and foremost attachment screw in the subframe is 725 mm, see illustration. Use of the foremost body adaptation bracket, which is factory-fitted, ensures that the attachment is sufficiently far forward Scania CV AB 2017, Sweden 8 (9)

9 Attachments in the rear section (B) and rear end (C) of the vehicle Fit the subframe with rigid attachments so that they give the necessary rigidity between the subframe and chassis frame. The attachments must control the sideways movement of the subframe. Attachments at the transition between the vehicle s front section and rear section (D). Different driving conditions require different limitations in mobility between the chassis frame and the subframe. Increase or decrease the mobility between the subframe and chassis frame by adapting and redistributing the attachments in the transition between the vehicle s front section and rear section (D). More flexible attachments located further back give increased mobility and more rigid attachments located further forward give reduced mobility. A B C D Scania CV AB 2017, Sweden 9 (9)