Brake system and boom section stress of truck crane

Generally speaking, cars exercise more than16000Kilometers, brake pads need to be replaced, but can not be used to simply use the mileage to determine the cycle of car replacement brake pads, especially for this special car。There are two main points to identify whether to replace the brake pads: first, listen to whether the wheel has friction, if there is, no matter how many miles have been driven, the brake pads should be replaced;Another distinguishing factor is to observe the thickness of the brake pads, a new brake pad thickness is15Mm or so, if the thickness of the brake pads is only left due to wear5Mm should be replaced in time, and to choose a regular manufacturer with a certificate of product。 In addition, in the daily maintenance of the brake pads, the following methods can reduce the excessive wear of the brake pads。
1In the process of continuing down a steep slope, the speed can be reduced in advance, the appropriate gear can be used, and the operation mode of the engine brake with the brake system can be used to reduce the burden on the brake pads of the brake system。

2In the road through curves, slopes, Bridges, narrow roads and difficult to see places, to reduce the speed, to ensure driving safety, but also to prevent excessive brake wear。

3The engine is prohibited to be extinguished during the downhill process, once the engine is turned off, the brake booster pump not only plays no auxiliary role, but also produces great resistance to the brake master pump, and the braking distance will be multiplied。
 

Truck mounted craneCalculation of section stress of boom

When calculating the cross section stress of the crane arm, the cross section data should be used reasonably. Generally speaking, the cross section is located on the position of the large tensile and compressive stress?The thickness of the lower plate should be greater than that of the side plate，According to the force analysis and the lifting arm, there are more damage appearances，The lower plate is prone to buckling and wrinkling，Therefore, the thickness of the lower plate should be relatively large;When determining the section specification，The rope capacity of the drum should first be determined according to the working height of the crane in the scheme，Then determine the approximate width of the drum，The contact elastic cylinder specification further determines the width specification of the boom，Under the premise of satisfying the internal organizational space requirements，The height specification of the section of the boom is generally width1.5—1.8倍。In addition to satisfactory calculation of the stress value and the aforementioned spatial calculation criteria, the scheme of the boom section specification should choose a smaller section specification and a larger plate thickness specification as much as possible for the stability of the forward section。The section stress of each boom should be calculated separately, and the calculated stress of each arm should be roughly equal, and the calculated stress value of each arm should gradually increase from the fixed arm, so that when the boom is overloaded and tortuous, the forearm will be damaged first, and the loss can be reduced to a low level。 The folding arm is in the elastic lifting arm scheme，The accounting of lap length can not be ignored，Because in the equivalent work of high and low and lifting torque，The length of the lap selects the contact pressure of the two arms，So in addition to the need to calculate the contact strength，The increase in friction resistance caused by the addition of contact pressure should also be considered，The effect on the composition of elastic ability。In the industry standard, the elastic ability of truck crane is not clearly stipulated, and the elastic ability of each factory product is not the same;In the work of the internship program, it is generally believed that the small flexibility should ensure that the corresponding rated load of the elastic load can be relaxed when the crane is normally lubricated。