NEWS Center

29

2022

-

07

What are the failure modes of imported friction pads

Classification:


【Summary description】The steel wire rope and liner will experience relative displacement, and the rough surface of the steel wire rope will pull scratches on the surface of the liner. That is to say, the gasket can cause sliding wear. The longer the relative displacement distance, the more severe the sliding wear. The occurrence of sliding wear is closely related to the friction coefficient of the material.

1、 Wear of imported friction pads

Wear is divided into sliding wear, adhesive wear, and uneven wear.

(1) Sliding wear

The steel wire rope and liner will experience relative displacement, and the rough surface of the steel wire rope will pull scratches on the surface of the liner. That is to say, the gasket can cause sliding wear. The longer the relative displacement distance, the more severe the sliding wear. The occurrence of sliding wear is closely related to the friction coefficient of the material. Manufacturers of imported friction pads believe that under the same conditions, the higher the friction coefficient, the shorter the relative sliding distance, and the smaller the sliding wear.

(2) Adhesive wear

In lifting work, the steel wire rope often comes into contact with the lining. Under the action of alternating pressure, a small lining material - the lining - is attached to the surface of the high-strength steel wire rope, causing wear and tear.

Adhesive wear is related to the binding force between material molecules. The addition of inorganic compound in the material will destroy the consistency of the material, reduce the intermolecular adhesion, and increase the adhesive wear. If the selection of friction pad material meets the normal operation of the elevator, sliding wear and adhesive wear are normal losses.

(3) Uneven wear

Inconsistent wear and tear at the end of the rope: During the use of the lining, the working state of each rope must be the same, and the wear and tear of the rope must be consistent. If a rope is mixed together and different from others, it can be determined that the working state of a certain wire rope has changed. At this time, it is necessary to adjust the wire rope and adjust the rope groove. The rope is trimmed: the entire rope is oval shaped, which is because a certain steel wire rope has an abnormality and needs to be removed, while adjusting the rope groove.

II

The equipment is operating normally, and the pressure on the gasket is less than 3MPa. The manufacturer of the friction imported gasket believes that this pressure is much lower than the compressive strength and will not cause damage. The steel wire rope and the cushion are mixed with coal ash in the same medium and medium, so that these hard points grow onto the cushion under appropriate conditions, forming pits on the cushion surface. The pits then expand under multiple actions of the particles. Afterwards, the oil enters the pit. When the pressure is greater than the material's load-bearing capacity, the weak points of the material, i.e. the concave edges, uniformly crack and act multiple times to crack, eventually becoming larger and deeper. The fragments are connected together, and the next cycle begins. Moreover, the ring speed increases, time shrinks, the elasticity and toughness of the material increase, the rate of pitting and peeling increases, and the material with good elastic potential is fixed. After the particle presses against the outer space, the pits quickly recover. That is to say, when forming pits, the particles act more frequently. Good material, slow crack protection and combat speed.

Therefore, similar materials, high hardness, poor endothelial performance, and almost corrosive usage are the main reasons for the wear of imported gaskets.

The material performance drops sharply at a certain depth. Once this phenomenon occurs, it is necessary to remove unnecessary oil and impurities between the wire rope and the surface as soon as possible.

3、 Pad wear usually occurs at the edge of the rope barrel, and the manufacturer of imported pads believes that there are two main reasons for friction. One is material aging. Another reason is that the material is subjected to greater alternating stress.

In the first case, due to fundamental changes in material properties, there is a high risk of continuous use of the pad. The manufacturer of the imported friction pad suggests that it must be replaced immediately.

In the second case, alternating stress is generated due to the inconsistency between the diameter of certain rope grooves and the diameter of steel wire ropes. The diameter of the steel wire rope is greater than the diameter of the rope groove. When the steel wire rope enters the rope groove, the side of the rope groove, especially the sharp corner of the rope groove, is subjected to the maximum compression pressure, tightly wrapping the steel wire rope. When the steel wire rope leaves the rope groove, the sharp corner is pulled outward, and the compression pressure disappears. When used multiple times, the material organization will experience fatigue. When the organizational structural force is less than the external applied compression pressure, sharp corners will be generated.

Poor equipment balance adjustment can cause shaking or vibration of the steel wire rope during the operation of the elevator. The kinetic energy generated by shaking and vibration can act on the liner for a long time, and may also cause the edges of the liner groove to fall in weaker areas. However, the manufacturer of friction imported pads believes that in this case, the size of the blocks falling from each groove may vary depending on the degree of swing of the steel wire rope, or a circle of rope may fall off.