HOW IMPORTANT IS THE WEAR OF SLIDING GUIDE SHOES TO ELEVATOR OPERATION?丨Potensi Elevator

author: Potensi-Ella
11/04/2022
HOW IMPORTANT IS THE WEAR OF SLIDING GUIDE SHOES TO ELEVATOR OPERATION?

As an integral part of a building, elevator energy consumption is also an important performance indicator in building energy consumption. At present, reducing the huge elevator energy consumption has become an important indicator pursued by the elevator industry. The guide shoe is the guide device of the elevator in direct contact with the working plane of the guide rail, so there will be a large friction loss in the process of the elevator transporting passengers and goods. Therefore, it is of great engineering value to analyze the factors affecting the friction between the guide shoe and the guide rail to reduce friction and consumption.

Elevator Guide Shoe

1. The role of guide shoes

Guide shoe is a device to prevent the car and counterweight from skewing when running up and down to ensure the smooth running of the elevator. The guide shoes are installed on the car and the counterweight device, and the car guide shoes are installed on the upper beam of the car and under the safety clamp seat at the bottom of the car. A total of four sets of counterweight guide shoes are installed on the upper and bottom of the counterweight frame. set. When working, the concave grooves (or rollers) of the guide shoe cooperate with the convex working surface of the guide rail, so that the car and the counterweight device only move up and down along the working surface of the guide rail, preventing the car and the counterweight device from skewing during operation or swing.

The guide shoe can be divided into sliding guide shoe and roller guide shoe according to the different movement modes between the guide shoe and the working surface of the guide rail. Sliding guide shoes are divided into fixed sliding guide shoes and elastic sliding guide shoes

Elevator Slider Guide Shoe

according to whether the axial position of the shoe head is adjustable. The fixed sliding guide shoe is mainly composed of a shoe lining and a shoe seat. It is also called a rigid sliding guide shoe. Because of its shoe head position, there is a large gap between the shoe lining of the fixed guide shoe and the top surface and both sides of the guide rail. Generally, it is about 05~10mm. Large vibration and shock will be generated during movement, so it is usually used for elevators below 1m/s that do not require high running quality. Because of its simple structure and high rigidity and strong bearing capacity, it is widely used in low-speed and large-tonnage freight elevators.sliding guide shoe

The elastic sliding guide shoe is composed of a shoe seat, a shoe head, a shoe lining, a shoe shaft, a compression spring or a rubber spring adjusting sleeve or an adjusting nut. The elastic sliding guide shoe is further divided into one-way floating spring type and rubber spring type sliding guide shoe. For the one-way floating spring-type sliding guide shoe, it can play a buffering role in the direction perpendicular to the top surface of the guide rail, but there is still a large gap between it and the working surface on the side of the guide rail, which makes it difficult for the working surface on both sides of the guide rail. There is no buffering effect on the vibration and impact of the upper guide shoe, so the rated speed of the elevator with this structure guide shoe is generally limited to 1.75m/s. The rubber spring elastic sliding guide shoe has a certain directionality, so the working surface on both sides of the guide rail has a certain directionality. The cushioning performance on the upper has also been improved, and the applicable elevator speed range has also been increased accordingly.

Elevator ShoeElevator Slider Guide Shoe

2.Spring sliding guide shoe

The rolling guide shoe is also called the roller guide shoe. It consists of a roller, a spring, and a rocker arm of the shoe seat. Because the roller guide shoe adopts rolling contact, it can reduce the frictional resistance between the guide shoe and the guide rail, reduce vibration and noise, and is often used in high-speed elevators.

3. The main factors affecting the friction of the guide shoe

The friction between the elevator guide shoe and the guide rail is a dynamic and complex process with many factors coupled, which will be affected by many factors such as shoe lining material, lubrication state, relative speed of contact load and surface roughness.
 
  1. Boot lining material. The lining material of the sliding guide shoe is generally wear-resistant nylon hard plastic, glass fiber cast iron or other polymer materials. By comparing the data under different materials, it can be known that the materials of different shoe linings have different friction characteristics.
  2. Lubrication state. Under lubricated conditions, an oil film will be formed between the guide rail and the shoe lining to separate the shoe lining and the guide rail and convert dry friction into wet friction, which greatly reduces the friction factor and reduces friction. In general, the friction force under lubricated conditions is much smaller than that under dry friction. Therefore, the sliding guide shoes are generally lubricated to reduce friction.
  3. Contact pressure. The contact pressure of the guide shoe to the guide rail surface mainly comes from the balance reaction force generated by the offset of the car load. This normal pressure on the guide shoe can sometimes reach more than 1000. Different materials have different friction sensitivity to contact load. Generally speaking, the friction coefficient will decrease with the increase of normal pressure. Although the friction factor is reduced, the overall frictional force is increased due to the increase in pressure.
  4. Running speed. Under the condition of certain pressure, the wear will increase with the increase of speed and after reaching a certain maximum value, it will decrease with the increase of sliding speed.
  5. Surface roughness. Under the same load conditions, the rougher the surface, the greater the friction and the more serious the wear. There is a most reasonable surface roughness under each load, when the wear is the smallest, and the wear will increase after this roughness. This is because the surface roughness is too small to increase the contact area, and the intermolecular attraction enhances the lubricant can not be stored in the friction surface, which is easy to cause adhesion and friction seizure.

4.Daily maintenance of guide shoes

The maintenance and inspection of the sliding guide shoes after the elevator is put into operation should be carried out from the following aspects.
 
  1. The clearance between the side of the car guide shoe and the guide rail is 05~1mm, and the adjustment range of the guide shoe spring without gap between the elastic sliding guide shoe lining and the top surface of the guide rail does not exceed the standard. The clearance between the fixed sliding guide shoe lining and the top surface of the guide rail is 1-2mm. The clearance between the shoe lining of the counterweight guide shoe and the top surface of the guide rail is not more than 2.5mm.
  2. Check the upper guide shoe and counterweight guide shoe of the car. People stand on the top of the car, run the car and counterweight in a horizontal position suitable for inspection, and swing the car or the counterweight frame back and forth to check the side clearance and head clearance and the wear of the shoe lining. Check the spring force. Check the lower guide shoes of the car: the maintenance personnel should stand in the pit and run the car to the bottom suitable for inspection position, and check the guide shoes by shaking the car back and forth, left and right. If the top clearance is too large, remove the boot lining and add a shim on its top surface for adjustment. If the side clearance is too large, the side clearance can be adjusted by adjusting the bolts for the insert shoe lining. The integral boot lining can be adjusted by adding a shim on the back of the boot lining side to make the gap slightly larger. If the effect is not ideal after adjustment, the best way is to replace the new boot lining.
  3. Keep the guide rail clean and lubricated and remove the dirt on the guide rail surface and the shoe lining in time. The up and down movement of the car will drive the flow of air in the hoistway and the flying of sand and dust. These sand and dust are easily adsorbed on the working surface of the guide rail and cause serious wear of the shoe and guide rail. Therefore, the working surface of the sliding guide shoe should be cleaned according to the regulations to ensure the normal operation of the guide shoe, reduce the friction noise during operation, and improve the use of the shoe lining. life.
  4. Severe wear of the shoe lining, foreign objects stuck in, excessive clearance or skewed installation will cause the rail gnawing phenomenon when the car is running. During routine maintenance, it is found that there are small and bright scratches on the side of the guide rail. In serious cases, there are burrs on the traces. The side of the shoe lining is not uniformly worn and there are burrs. Judging that gnawing has occurred. There are many reasons for the gnawing of the rails, mainly because the guide rail installation is twisted and skewed or the upper and lower guide shoes are loose and the installation is not aligned, and the gap between the guide rails is inconsistent with the guide rail gap. At this time, it should be adjusted to eliminate rail gnawing and replace the shoe lining according to the specific reasons.

Whether the shoe lining of the sliding guide shoe is made of iron, nylon or hard plastic, there is always friction between the shoe lining and the guide rail during the operation of the elevator. This frictional force not only increases the load of the traction machine, but also is one of the reasons for the vibration and noise of the car during operation. In order to reduce the friction between the guide shoe and the guide rail, save energy, improve the riding comfort, and strengthen the daily inspection and maintenance of the guide shoe, cleaning, lubrication, adjustment and timely replacement of the shoe lining, the roller guide shoe can be replaced if necessary.

Related products:Mitsubishi elevator guide shoe  Elevator guide shoe L10 
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