The use and maintenance of elevator guide shoes

At present, how to reduce noise, improve comfort, and reduce the leveling error of elevators produced in China is a problem worthy of study. There are many reasons for this problem, one of the main reasons is how to choose, maintain and repair the guide shoes. Inappropriate specifications of the guide shoe and guide rail or improper assembly clearance and wear of the guide shoe shoe lining will cause the car to shake or produce friction noise, and even the guide shoe may be in danger of falling off the guide rail.

1 Types of sliding guide shoes

1.1 Car guide shoe

Roller guide shoes can be divided into sliding guide shoes and rolling guide shoes according to their movement mode on the working surface of the guide rail.

Sliding guide shoe The sliding guide shoe can be divided into fixed sliding guide shoe and elastic sliding guide shoe according to whether the axial position of the shoe head is fixed or floating. The fixed sliding guide shoe (also known as the rigid sliding guide shoe) is shown in Figure 1 (please click), there is a large gap between the guide shoe and the guide rail, which will generate large vibration and impact during movement, so it is usually used for 1m Elevators below /s. However, it has a simple structure, good rigidity and strong bearing capacity, and is widely used in low-speed and large-tonnage freight elevators with a load of more than 3 000kg and a speed of less than 0.5m/s. The elastic sliding guide shoe is shown in Figure 2 (please click), and it is 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 end face of the guide rail, but there is still a large gap between it and the working surface of the guide rail side, which makes it difficult for the working surface of the guide rail side. Vibration and shock in the direction have no mitigation effect. The upper limit of the rated speed of the elevator using this guide shoe is 1.75m/s. The rubber spring type elastic sliding guide shoe has a certain directionality, so it also has a certain buffering performance in the direction of the working surface of the guide rail side, its working performance is better, and the applicable elevator speed range is also correspondingly increased.

The initial pressing force of the shoe lining of the elastic sliding guide shoe on the end face of the guide rail is adjustable. The selection of the initial pressure mainly considers the partial gravity, which is related to the rated load of the elevator, the size of the car and the position of the center of gravity. The dimension b in Fig. 2 realizes the adjustment of the initial pressure by adjusting the spring. That is, it reflects the compressed amount of the spring. For the elastic movable guide shoe of domestic elevator, its value should be selected according to Table 1 (please click).

When the elastic sliding guide shoe lining is worn, the contact pressure will drop. If the wear amount is not large, the screw can be rotated to adjust, and the shoe head can be pushed forward to increase the contact pressure and ensure the smooth operation of the car, but the contact pressure It should not be too large, otherwise it will increase the running resistance and accelerate the wear of the boot lining. The shoe head can automatically rotate in the shoe seat. When the guide rail is not installed straight or the upper and lower ends of the shoe lining side are worn unevenly, the slight swing of the shoe head can be compensated to prevent the car from vibrating or jamming. Some elevator manufacturers supply two kinds of shoe linings at the same time, one is cast iron, which is installed in the shoe head for running in the guide rail at the beginning of use. One is nylon, and the guide rail will be replaced by the user (unit of use) after running in. The advantage is that the wear of the guide shoe can be slowed down, and the use of the running-in guide rail can improve the surface roughness of the guide rail and overcome the processing defects.

Rolling guide shoe The rolling guide shoe, also known as the roller guide shoe, is shown in Figure 3 (please click), due to the use of rolling contact, it can reduce the frictional resistance between the guide shoe and the guide rail, save power, reduce vibration and noise, and are used in high-speed elevators and On the mine elevator (above 2m/s). The initial pressure of the roller to the guide rail is adjusted by adjusting the compressed amount of the spring. The rollers should not be skewed to the guide rail, and should contact the working surface of the guide rail evenly over the entire width of the rim. When the car is running, the three rollers should roll at the same time to keep the car running smoothly.

The use of roller guide shoes is not allowed to add lubricating oil on the working surface of the guide rail to avoid slippage. The sliding guide shoe needs to be lubricated to reduce frictional resistance. Usually, the oil box is placed on the top of the two upper guide shoes as shown in Figure 4 (please click), and the lubricating oil in the oil box is evenly applied to the working surface of the guide rail through the felt to achieve the purpose of automatic lubrication.

1.2 Pair heavy guide boots

The structure of the counterweight guide shoe is simpler than that of the car guide shoe as shown in Figure 5 (please click). The two sides of the boot lining are clamped by angle steel, and the angle steel is installed on the counterweight frame. Depending on the material of manufacture, there are two structural forms for boot linings.

2 Repair and inspection of guide shoes

2.1 Troubleshooting and troubleshooting of guide shoes

There are many reasons why the elevator vibrates or has friction noise during operation. Here, the possible causes and elimination methods are only proposed from the fault phenomenon of the guide shoe.

1) There is a foreign object stuck in the oil tank of the shoe lining, and the foreign object should be removed and the shoe lining should be cleaned.

2) The shoe lining is severely worn, causing friction between the metal cover plates at both ends and the guide rail, and the shoe lining should be replaced.

3) If the clearance between the working surfaces of the guide rails on both sides of the hoistway is too large, the guide shoes should be adjusted to maintain the normal top clearance.

4) The wear of the shoe lining is uneven or very serious. The shoe lining should be replaced or the side lining of the insert shoe lining should be adjusted, and the guide shoe spring should be adjusted to make the pressure of the four guide shoes uniform.

5) The rollers of the rolling guide shoes are unevenly worn, and the rollers of the rolling guide shoes or the repair rollers should be replaced.

2.2 Maintenance and inspection of guide shoes

1) The clearance between the side of the shoe lining of the car guide shoe and the guide rail is 0.5 to 1 mm. There is no gap between the elastic sliding guide shoe lining and the top surface of the guide rail, and the adjustment range of the guide shoe spring does not exceed 5mm. The gap between the fixed sliding guide shoe lining and the top surface of the guide rail is 1 to 2 mm. 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. The clearance between the roller of the rolling guide shoe and the guide surface is 1 to 2 mm.

2) Run the car and the counterweight at the same level, and check the guide shoes on the upper part of the car and the counterweight. Swing the car or counterweight frame back and forth to both sides, you can check the size of the backlash and the wear of the shoe lining, and also check the hardness of the spring. If the top clearance is too large, you can remove the boot lining and add shims on its top surface for adjustment. If the side clearance is too large, if it is a insert type shoe lining, the side shoe lining bolts can be screwed in to adjust the side clearance. The integral boot lining can be adjusted by adding a shim on the back of the boot lining side, so that the gap is slightly larger on one side, but due to structural reasons, the effect is not as good as the insert type, so the best way is to replace the new boot lining.

Check the fastening of the guide shoe, the car frame and the counterweight frame. It is best to use a spring washer to prevent the nut from loosening.

3) The shoe lining is seriously worn, the clearance is too large or the installation is skewed, which will cause the car to "gnaw the road". The phenomenon of "biting the road" can be judged by the following signs: there is a small and bright trace on the side of the guide rail, and the trace has burrs in severe cases; the side of the boot lining is flared and has burrs; the car is running, especially when starting Deviated and twisted when leveling. The reasons for "gnawing" are: the guide rail is twisted, skewed or loose; the installation of the upper and lower guide shoes is not aligned and inconsistent with the guide rail clearance; the car frame is deformed or the shoe seat bolt is loose; the outer dimension of the shoe lining is too small in the shoe head shaking.

4) Always pay attention to the lubrication of the guide rail, and remove the dirt in the boot lining in time. The working surface of the guide rail of the sliding guide shoe shall be cleaned according to the regulations, refueled once a week, and cleaned once a year. If there is an automatic oiling device, use HJ-40 lubricating oil, and if there is no automatic oiling device, use calcium-based grease. Do not add lubricating oil to the working surface of the rolling guide shoe guide rail, but the working surface should be clean, and the roller should not have obvious slippage during operation. The rolling guide shoe bearing is injected with calcium-based grease once a month and cleaned once every six months.